Types of superglues, their properties and applications

Second glue, well known in the window industry, was invented during World War II in 1942 by the American chemist Harry Coover. Like all ingenious things, glue was discovered completely by accident. During those war years, Coover worked for and searched for transparent plastics for optical sights.

The invented substance is cyanoacrylic acid ester, cyanoacrylate, - CH2 = C(CN)COOR. Cyanoacrylate was unsuitable for the task, because at the slightest presence of moisture the substance became sticky and sticky.

In 1951, cyanoacrylate was again remembered during the creation of heat-resistant coatings for jet aircraft. Coover and his colleague Fred Joyner had a large list of different materials whose properties they studied using various instruments. After finishing work with one of the cyanoacrylates, with serial number 910 in the list, Joyner discovered that the lenses of one of the devices were tightly stuck together.

Harry Coover remembered his search in 1942 and decided that a “superglue” could be created using cyanoacrylate. The scientist convinced his company of this. Coover and Joyner spent about seven years developing the optimal formulation. In 1958, the first “superglue” was introduced to the market. Superglue was assigned its serial number from the list of the previous discovery - Eastman 910.

Initially, the glue did not become popular. The situation began to change after Harry Coover visited a television show that was popular in America at that time and demonstrated the capabilities of glue. Superglue has long been present on various American talk shows, where all its new and amazing properties were demonstrated. Cyanoacrylate glue could bond any surface, even if it was not properly protected first.

Although Gorrie Coover never managed to get rich from his invention, superglue gained popularity after the patent expired. was unable to gain much financial benefit from superglue and sold the business in 1980.

History of the invention of glue

Superglue began its history in 1942. It was at this time that the American chemist G. Coover, while conducting experiments with cyanoacrylate, obtained a new substance with unique adhesive abilities. Initially, the scientist did not have a goal to create glue; he worked on improving transparent plastic for optics, working at. Therefore, superglue, as a by-product, was ignored for some time.

We remembered the cyanoacrylate composition 9 years later when searching for a universal adhesive with waterproof and heat-resistant properties for the aircraft industry. At that time, it was too sticky and spoiled if it came into even the slightest contact with moisture. After extensive work, Harry Coover and his colleagues improved the composition and obtained a high-quality base for the glue.

Another 7 years later, in 1958, superglue appeared on the market under the brand name Eastman 910. But it did not become popular immediately, but only after the release of a television program about its properties. The inventor smeared a cable and a metal rod with superglue, connected them, and after drying, hung on the structure in the air - the strength of the composition was enough to support the weight of a person. Afterwards, the patent for the production of superglue was given to the National Starch company, and later many brands began to produce it.

Features of the composition of superglue

The molecular formula is the same for all cyanoacrylate adhesives: CH2 = C(CN)COOR. This is a liquid cyanoacrylate monomer, or cyanoacrylic acid ester. R is a radical, it can be ethyl, methyl, butyl and other monovalent radicals, depending on which the technical characteristics of the glue change. Any superglue contains up to 97-99% cyanoacrylate, as well as the following substances:

• plasticizers – give superglue elasticity;
• stabilizers - keep the glue quite liquid before application and provide the necessary properties after hardening;
• thickeners – provide the necessary thickness and consistency of the gel;
• modifiers - necessary to enhance the water resistance of superglue to the level of D3-D4, heat resistance (divinylbenzene, cyclopentadiene and others);
• adhesion enhancers – increase the adhesion strength of glue (PVA, polyacrylic);
• curing activators (needed when there is insufficient humidity) or curing inhibitors (to prevent spontaneous polymerization);
• fine metal powders - to improve the conduction of electricity.

Unlike other adhesives, superglues do not contain organic solvents. This makes them safer for humans and also suitable for gluing metal. On sale you can find different types of superglues, which are supplied in the form of blisters, tubes, jars, and adhesive tapes. They have a common feature: a small volume of packaging, because after opening it, even with a slight decrease in the tightness, the gel glue quickly becomes viscous and then completely deteriorates.

Properties and technical characteristics of superglue

Superglue is often called “second glue”; its feature is that it hardens very quickly in air, on the fingers. How long does it take for superglue to dry? Typically, the composition hardens in 5-60 seconds, but 6-24 hours are required before complete curing and use. At low humidity, curing of superglue can take up to a couple of minutes, but upon contact with water and high humidity it occurs almost instantly.

Other properties and characteristics of the product:

• the glue holds the parts firmly even when applying a thin layer, the main thing is to press the base tightly;
• The superglue seam can withstand high loads - up to 150-250 kg/sq.m. cm;
• dried superglue is a translucent, medium-elastic mass;
• most superglues can withstand temperatures in the range of -60...+80 degrees, are very frost-resistant, do not react to the action of gasoline, oils, alcohol;
• some compositions not only work well in the cold, but are also heat-resistant and do not deteriorate at temperatures up to +250 degrees;
• superglues, without the introduction of special additives, conduct current poorly and can serve as electrical insulating compounds;
• the product can be applied if there are gaps up to 0.1 mm, although some superglues have increased viscosity, so they can seal gaps up to 0.25 mm (larger gaps are best filled with epoxy or polyurethane);
• superglue consumption is very low - a drop can cover a circle with a diameter of 2.5 cm;
• Most formulations are one-component, but two-component superglues are also commercially available.

Adhesives are characterized by high adhesion strength to many materials, including when connecting dissimilar surfaces. They are suitable for plastic, glass, wood, metal, rubber, ceramics. Superglues can be used on vertical, horizontal, and inclined products. Not suitable only for Teflon, silicone, polyethylene; it is also prohibited to glue dishes that come into contact with food with them.

It is better to avoid contact of the adhesive joint with acetone, dimethyl sulfoxide, and isopropanol, since superglues are unstable to these substances. The fracture strength of the joint will not be too high, since the elasticity of the composition is average.

Super glue

Superglue, along with many great inventions, was born by accident, but, as befits a substance with such a name, it has firmly established itself in a variety of economic sectors. In this article we will tell you what superglue is and what it comes in, what it can and cannot do, and we will also share useful tips and tricks for using such glue.

“Superglue” is the Russian translation of the trademark “Super Glue”. In the USSR, superglue was produced under the name “Tsiakrin”, and today you can find on sale the brands “Super-moment”, “Secunda”, “Monolith”, “Elephant”, “Pattex”, “Sila”, “Cyanopan”, “Glue” - which are essentially the same product.

What is superglue

The composition of the substance that we used to call “superglue” necessarily includes 97–99% cyanoacrylates, that is, cyanoacrylic acid esters, plasticizers, stabilizers, and in case of insufficient moisture in the joint - activators, as well as retarders.

To obtain an adhesive gel, ultrafine silicon oxide is also added to the composition for thickening. Solvents are not included in superglue.

The mechanism of action of superglue is actually simple - under the influence of slightly alkaline agents (ordinary water is one of these substances, and atmospheric humidity is quite sufficient), the substance polymerizes, i.e. hardens, becomes hard, while reliably fastening both surfaces together.

Conventional adhesives based on cyanoacrylates can easily withstand a load of 150 kg/cm2, and more advanced ones, for example, BlackMax from Loctite - 250 kg/cm2. The heat resistance of regular superglue is up to 70–80 degrees, modified - up to 125 degrees.

Classification of superglue

In our country, it is customary to call any glue that contains cyanoacrylates and hardens almost instantly “superglue.” However, in fact, there are several varieties of this substance:

One-component superglue based on ethyl cyanoacrylate. As the name implies, it does not contain additional active substances. It perfectly glues a variety of surfaces and hardens quickly - for this useful property it is called second glue. The full hardening period does not exceed 24 hours at air humidity of at least 55%, but in general, after just a minute the surfaces are held securely, and after two hours the glued object can be used without fear.

Two-component. An adhesive that contains not only a cyanoacrylate binder, but also fillers that give it thermal and electrical conductive properties. The remaining characteristics of the two-component adhesive are similar to the one-component composition.

Depending on their consistency, superglues are divided into:

1. Liquid, they are thin or penetrating. They are used only where the gap is very small - they penetrate perfectly between two tightly fitting parts, into holes less than 0.05 millimeters thick. 2. Average. Universal adhesives that have the widest range of applications. 3. Viscous or gel-like. Capable of filling small voids.

The history of superglue

Like a lot of other ingenious inventions, superglue was discovered completely by accident, not once, but twice. The American chemist Harry Coover was not at all busy searching for the ideal adhesive; in 1942, the development of plastic for optical sights was much more urgent.

Coover used cyanoacrylates in his work, but quickly abandoned his idea, since these substances tightly adhered to any surface and laboratory equipment quickly failed.

Unfortunately, at that time, Harry Coover did not appreciate all the prospects of the accidentally discovered properties of cyanoacrylates and continued to work on improving optical sights with other materials.

It was only in 1951, 9 years after the first discovery, that the chemist, working with his colleague Fred Joyner to create an acrylic polymer for jet canopies, again encountered the amazing properties of cyanoacrylates and this time decided to take the creation of superglue seriously.

It took the scientist another seven years to develop the optimal composition of the substance, adding stabilizers and plasticizers, and finally, in 1958, EastmanCompound 910 was ready for use.

By the way, the Russian name “superglue”, which we usually call all adhesives based on cyanoacrylates, is tracing paper with SuperGlue - under this name Dr. Harry Coover patented his composition. It's a pity, but superglue began to make a profit only after the SuperGlue patent expired. However, Harry Coover deservedly received his share of fame, he himself starred in advertising for his invention and was awarded the US National Medal of Technology and Innovation.

Scope of application of superglue

Superglue is widely used in a variety of fields of activity - in everyday life, industry, production, instrument and mechanical engineering, repair and construction. For the most part, “superglue” is used for gluing non-porous or water-containing materials. First of all, cyanoacrylate adhesives are used where quick gluing is required: for rubber seals in window production, for attaching mounted radio elements, parts of components in instrument making, optical parts, microcircuits, racks, washers, mounting harnesses and individual conductors to the bases of boards, as well as for securing other elements of radio equipment. In everyday life, the amateur method of using superglue and baking soda as an epoxy composition for filling seams, cracks, and chips is often used. The mixture hardens instantly and resembles acrylic-like plastic. The seam is successively filled with baking soda, moistened with superglue and in this case playing the role of not only a filler, but also an alkaline polymerizing agent. In some cases, the mixture can successfully replace epoxy compositions, including those reinforced with fiberglass mesh, however, safety precautions should be taken due to the toxicity of the resulting mixture. You can also use finely ground plaster or concrete as a filler, for example, dust obtained when drilling holes in such materials.

Currently, the number of modifications of superglue is constantly growing, and accordingly, the scope of its use is expanding.

Thus, in medicine, superglue is already used as a sealant to stop bleeding and treat wounds. And not so long ago, Swedish scientists developed a superglue composition that will help treat fractures, including the spine and skull bones, without the use of metal plates.

Modern superglues can withstand enormous loads, so they can be used not only for gluing small parts, but also perform much larger tasks.

Thus, the new Loctite superglue is considered the strongest in the world and was included in the Guinness Book of Records. As evidence, two cars weighing over five tons together were glued with Loctite to a metal frame and raised to a considerable height. The cars lasted for some time, and the representatives of the Book of Records used only nine drops of superglue to glue them together!

According to scientists, over time, superglue will be able to replace welding and other, more labor-intensive types of connections.

As we can see, today superglue is truly universal and is used literally everywhere where dissimilar or small materials need to be glued together efficiently and as quickly as possible.

Pros and cons of cyanoacrylate superglue

Superglue is a very strong and reliable adhesive substance that has a number of advantages:

• high curing speed – at room temperature and within a few seconds; • high reliability of the connection – often the adhesive seam is stronger than the material being joined; • the ability to connect materials of different structures; • single-component, ensuring ease of use; • no need for special treatment of the surfaces to be joined; • resistance to temperature and humidity; • the ability to connect inclined, vertical, porous and absorbent surfaces; • vibration resistance and peel strength; • aesthetic, invisible adhesive seams.

Some of the disadvantages of superglue include:

• limitation of the possibilities of use with large gaps; • temperature restrictions – no more than 80-100 degrees Celsius; • rigidity of the connecting seam, i.e. inapplicability for connections experiencing fracture loads; • inapplicability for joining polypropylene, polyethylene, Teflon and silicones.

Super glue:

- does not dissolve in water, ethanol, dichloroethane and many other substances, but on the contrary, instantly hardens in places of contact with them. - softens from dimethyl sulfoxide, and also dissolves under the influence of heptane, acetone and isopropanol.

Shelf life. Cyanoacrylate adhesives are stored in sealed packaging in closed, ventilated areas, in places protected from moisture and direct sunlight. The guaranteed shelf life under these conditions at room temperature is 6 months, at a temperature not exceeding +5 °C - 12 months.

Constant contact with water or a damp environment leads to a gradual decrease in the strength of adhesive joints.

Instructions for use

First of all, superglue is suitable for hard materials with a smooth surface. It is less suitable for soft, absorbent and elastic materials (for example, for repairing leather clothing).

Moderately porous materials (eg wood) can be reliably bonded with longer setting times (30 seconds to 2 minutes). Glue is not suitable for highly absorbent materials. It is conditionally suitable for glass, since the adhesive joint dries out over time.

Since superglue sets within a few seconds, it is preferable to use for gluing small surfaces.

The thinner the adhesive layer, the more reliable the connection and the faster the glue sets, so it is not suitable for filling cracks and voids.

The glue is absolutely transparent and gives an almost invisible connection. Withstands SHORT-TERM exposure to water. Glued products can also be exposed to temperatures over a wide range: withstands any temperature up to +80 ° C (low temperatures - almost without restrictions).

The prerequisite for successful gluing is a perfectly clean and dry surface. If the material allows this, it is recommended to repeatedly wipe the gluing area with solvents (acetone, etc.). When gluing metals, simply clean the surface with sandpaper or a brush.

It is necessary to apply instant glue to one of the surfaces to be glued and immediately connect it to the second. Excess glue can be removed with a paper towel immediately after use.

Bonding of parts (depending on the material) occurs in a few seconds or a few minutes. Maximum bond strength is achieved after 12 hours.

The gluing area can be quickly dried with a hot hairdryer or sprinkled with baking soda. High humidity speeds up the gluing process, so you can blow on the applied adhesive to speed up the gluing process.

To remove Chinese superglue from fingers and various surfaces we use: - alcohol, - baking soda and warm water, which we wash with a sponge, - acetone or nail polish remover with acetone, - dimexide is sold in a pharmacy, it also removes foam from any surface . We wet the dried glue, wait 20 minutes, then wash it with a sponge, cloth or cotton pad soaked in dimexyl. After removing the glue, we wipe the surface with soapy water - a special liquid for washing off superglue - remove superglue from clothes and fabrics with a hot iron, several times ironing the fabric on the back side or through gauze on the outside, the glue cracks and crumbles under this influence. You can moisten the glue on the fabric with acetone and iron it with a hot iron.

The adhesive joint can be separated by heating up to 180°C and prolonged exposure to certain solvents.

Safety precautions when working with superglue

Since superglue hardens and glues surfaces instantly, and also has a number of other features, the following safety rules should be observed when working with this substance:

1. Even if you are as careful as possible, a drop of glue may still end up on your clothing, so be sure to protect your clothing. 2. Cyanoacrylate vapors are toxic - be sure to work with glue in a ventilated area. 3. Use the required amount of glue. You should not apply a lot of superglue for the following reasons: firstly, it will increase its hardening time and worsen the quality of work; and secondly, there is a high probability that the excess will protrude from the seam and fingers or other objects that were used to press the glued parts will stick very firmly to the part. 4. Since the glue sets instantly upon contact with atmospheric humidity, the tube spout often becomes clogged. Therefore, before reuse, it should be carefully cleaned with a needle or the tip of scissors. Under no circumstances should you press on the tube in the hope of punching it with force - the glue can shoot out a considerable distance, and in the best case, you will stain your clothes or table, in the worst case, the glue can get into your eyes. 5. The tube of glue should be directed away from you, preferably downwards, trying to cover it as much as possible with your hand, thereby eliminating the possibility of superglue getting into your face, especially your eyes - if the glue gets on the eye shell, it causes a serious burn, which requires long-term treatment and medical intervention! If glue splashes get into your mouth or eyes, they must be kept open and rinsed under running water for 15 minutes, after which be sure to consult a doctor. 6. You should not bend or fold a started tube of superglue. It breaks very easily at the bends - you will stain your hands, clothes, or ruin the part being glued.

And another serious danger is that when gluing materials that contain cellulose, such as cotton fabric and paper, there is a possibility of an exothermic reaction, that is, sudden heating and even ignition. That is why safety regulations prohibit the use of woolen and cotton clothes, especially cotton gloves, when working with glue that contains cyanoacrylates. Otherwise, you may get a burn, minor if there is not enough superglue, but serious if the amount is large enough.

Today, special types of superglue have already appeared, which, thanks to special additives, can be used for gluing cardboard and do not cause an exothermic reaction.

Poisonous properties of cyanoacrylates

Let us immediately note that in the hardened state, superglue is safe, so it can be used for gluing a cup or plate. BUT! You still shouldn’t drink hot tea from such a cup, because superglue softens when exposed to liquids at temperatures above 70 degrees. So we recommend using cyanoacrylate glue only for gluing decorative tableware, such as a painted plate or flower vase, and not for serving items from which you plan to eat.

In liquid form, directly during gluing, superglue releases toxic fumes, which in high concentrations can cause nausea and dizziness.

Therefore, we repeat, you should work with superglue in rooms with good ventilation.

However, there are special types of cyanoacrylates, for example, octyl-2-cyanoacrylate, which is the least toxic of all cyanoacrylates. Such adhesives are considered medical and were successfully used during the Vietnam War to stop bleeding, provide first aid to victims and glue wounds.

Today, the LifePath patch, developed with superglue, is applied to wounds when the surgeon cannot pinpoint the source of bleeding and firmly seals the damaged area, saving the patient's life.

So, not long ago, medical superglue saved the life of a three-month-old girl with a brain aneurysm. Specialists at the University of Kansas Clinic sealed the site of a rupture in the child’s artery with medical superglue, which literally “soldered” the site of hemorrhage into the brain in a few seconds.

Storage methods

It is likely that only a small amount of super glue will be used. This is because when it is opened, it quickly becomes unusable and the glue quickly hardens on the spout of the tube, which prevents the glue from coming out. To reduce this problem, always wipe the tube spout clean and store it upright to prevent glue from clogging the inside of the spout.

During storage, superglue dries quickly. In order for it to serve for a long time, it is not enough to close it with the “original” plug. After use, the bottle of glue should be placed in any suitable sized jar with a screw-on lid. Then it is stored for a long time. In this sealed form, it can be placed in the refrigerator for long-term storage. Additionally, you can add a handful of rice or silica gel to the jar to absorb water vapor. Rice absorbs water well from the air.

Another way to economically use and carefully store a tube of superglue: Unscrew the tip, pierce the foil on the tube, carefully tilting and perhaps barely squeezing the tube with your fingers, apply a drop to the needle, immediately turn the tube vertically so that the glue does not leak out anymore (and it flows new almost like water, even if you don’t put pressure on the tube), apply glue with a needle to the surfaces to be glued, glue it together, wipe the tube (with paper, preferably thin) from the glue near the puncture, and screw on the closed plastic spout, putting a couple of layers of cellophane on the neck of the tube (isolates the glue from air and is easy to tear off). As a result, the glue will not dry out in the tube and, with due care, can be reused as many times as necessary until it is completely used up.

A significant amount of superglue from the bottle can be poured into a syringe and closed with a needle bent with pliers for a tight seal. It also keeps for a long time.

How to carefully remove superglue from a plastic surface

Method 1

If the glue has not dried yet. You need to take a rag soaked in warm soapy water and quickly remove any spilled glue. Wipe the area with a degreaser (you can use nail polish remover).

Method 2

A gentle way. Suitable for delicate plastic surfaces. If you find an old, dried superglue stain that is ruining your desk, it will take much longer to clean it up.

You will need:

• A soft cloth;
• soap solution.

Soak a rag in the soapy water and, without squeezing, cover the superglue stain with it. With prolonged interaction with water, the glue softens and can be removed from the surface. It takes two to three hours for Moment glue to become soft, sometimes more. The amount of time depends on the amount of glue and how much it has dried. If during this time the rag dries out, it must be periodically moistened or covered with film.

This method can remove stains from plastic tables, glossy and painted surfaces.

Method 3

This method is universal and will help remove stains from any glue, including “moment” glue.

You will need:

• cotton pad or sponge;
• kerosene or gasoline.

Moisten a cotton pad or sponge with solvent and wipe the stain. This action should be repeated until the surface of the plastic is clean. It is important to note whether the plastic surface changes color during such cleaning. It will be unsightly if your table has a light spot that has to be hidden. If the plastic becomes lighter, you should stop the procedure and use method 2.

Method 4

You will need:

• rag;
• universal glass cleaner.

This method will help remove a stain of not completely dried superglue. The area of ​​contamination should be moistened generously and wiped with a dry cloth. If you were unable to clean it the first time, you should repeat the procedure until the plastic is completely clean.

Method 5

Another gentle method that will help remove a stain of dried glue.

You will need:

• rag;
• Dimexide – concentrate (99%).

Dimexide can be bought at any pharmacy. It is not as aggressive a solvent as, for example, acetone. In order to remove glue from plastic using this method, you should moisten a rag with the concentrate and wipe the stain. Do not leave a rag soaked in dimexide on a plastic surface. With prolonged exposure, the plastic may become deformed and succumb to dissolution. When working with Dimexide, care must be taken. It may cause skin irritation, so it is best to use rubber gloves.

Method 6

You will need:

• rag or cotton pad;
• ethanol

Ethanol can be purchased at a pharmacy. It won't dissolve super glue, but it will help soften it. A rag or cotton pad is moistened with alcohol and left on the stain. After this procedure, the glue is easier to remove mechanically. If the stain is not on the front surface of the product, but still catches your eye (for example, on the leg of a garden plastic table), then you should try to remove the softened glue with a knife or razor.

Method 7

Many superglue manufacturers have heard about the problem of removing their product from surfaces. They produce Anti-Glue product specifically for this purpose. You need to know exactly the brand and type of glue whose stain is bothering you.

When working with Anti-glue, you must follow the instructions. Usually it is simple: apply a layer of Anti-Glue to the dried glue for a couple of hours. After this, the glue can be easily removed from the surface by rolling.

Method 8

Thermal. If you are confident in the quality of the plastic, it is heat-resistant (for example, it is a heat-resistant plastic surface of a table or window sill), then you should try this method.

You will need:

• container (teapot, ladle, mug) with a flat bottom;
• hot water.

Hot water is poured into a container or heated directly in it. It must be placed on the spot of glue “moment” and wait. Only heat-resistant glue can withstand high temperatures. After heating, removing the glue from the plastic is not difficult.

When working with superglue, you should be very careful. Removing it from any surface is a very labor-intensive process. If you drop or spill it on a plastic table, you need to be prepared for a number of difficulties.

The difficulty in removing superglue from plastic surfaces is that there is a chance of staining or damage. To clean plastic, you should use strong solvents such as acetone or white spirit; they can chemically damage the plastic or leave discolored spots on it. If this is the only option, try first on an invisible part of the product.

Useful tips

In this section we will answer the most popular questions that arise when using superglue.

Gluing small parts:

Does superglue conduct current? Regular one-component superglue is not, it is an insulator. There are special adhesives that, with the help of special fillers, obtain the ability to conduct current or heat.

Yes Easy!

WD-40 is great for removing superglue. Spray, wait a minute and separate from skin and hair.

Other different ways:

1. Wet the area stained with superglue with warm water and soap thoroughly. The soap solution needs to be foamed properly. And, preferably, rub with a pumice stone or a stiff brush. This step should already improve the situation by 50 percent. 2. Then put some salt on the super glue. 3. Add a little more water to the salt. 4. Now rub the salt into the problem area for one minute. 5. A white paste should form. 6. Wash your hands and there will be no trace of glue left.

Superglue often sticks fingers together, since working in rubber or latex gloves is not very convenient when it comes to small parts, and cotton gloves, as we remember, cannot be used. A special anti-glue solvent will help you cope with the problem; you can also simply wash your hands with hot water and soap and rub with a washcloth, use acetone or Dimexide pharmaceutical solution.

If your fingers are stuck together, thoroughly moisten the glued fingers with acetone and wait. Acetone softens cyanoacrylate, but not instantly, do not try to immediately separate your fingers, especially by force, be patient! Do not let the acetone evaporate completely; it is advisable to apply a cloth well soaked in acetone to the gluing area; you do not have to wet your fingers every minute. In particularly difficult cases, sometimes you have to wait about 40-50 minutes - it depends on the glue and the area of ​​​​the glued fingers.

When using Dimexide, you should carefully read the instructions, since the drug is toxic and is intended for external use only. And don’t worry, even without using solvents, superglue will come off your fingers by itself in a couple of days.

How to remove superglue from clothes? If a drop of superglue gets on your favorite jeans or sweater, you should use an Anti-Glue solvent again. However, not all fabrics can boast the necessary resistance to this chemical, so try applying a little solvent to an inconspicuous area, and then clean the stain. Another option is to heat the glue stain with an iron through a thin fabric, alternately on one side and the other. Under the influence of high temperatures, the glue is destroyed and your clothes will become clean after intense heating with the iron. As long as the glue stains are not too dry, they can be removed from clothing with purified gasoline. Another option is to soak the fabric for a couple of hours in a soapy solution (2-3 tablespoons of washing powder + 1 tablespoon of ammonia), after which the problem areas should be scrubbed with an old toothbrush. And if the glue has frozen in drops on the surface of the fabric, it is better to fold the clothes into a plastic bag and put them in the freezer. After a few hours, try gently scraping off the frozen drops with a sharp knife, but remember: this method is not suitable for fabrics that require special care.

How to clean superglue from a table? If the surface of the table is covered with polish, then only the spot of the stain should be left open, and the rest should be covered with cellophane so as not to damage the polish. You can use pharmaceutical dimexide or solvent 647. Attempts to remove superglue from the surface of the table by heating with a soldering iron or iron are fraught with fire, and it is also unknown how the polish, varnish or paint itself will react to heating - together with the glue stain, the table may lose part of the surface itself . The simplest and most effective way is to use a kettle or ladle with boiling water - such a vessel should be placed on the glue stain for a while. Not a single ordinary superglue can withstand temperatures of 100 degrees, only modernized ones.

Baking soda + superglue

For working with superglue in thick layers, an amateur method is known with sequential filling of the seam with superglue and baking soda, which in this case plays the role of not only a filler, but also an alkaline polymerizing agent. The mixture hardens almost instantly, turning into an acrylic-like filled plastic, and in some cases can successfully replace epoxy compositions, including those reinforced with fiberglass mesh. The correct gluing sequence is: first moisten the surface with superglue, then cover it with soda, then moisten the soda with superglue again. In this case, the gluing will be as strong as possible.

The reaction of superglue with soda occurs with the release of temperature, as a result of which, when applied to plastics and porous materials, a very strong connection is obtained with the formation of molecular bonds. Moreover, the connection is so strong that most likely, the second time, the thing will break in a different place, but the superglue will hold up. Instead of soda, in some cases you can use cotton wool from cotton pads, graphite, salt and other available materials.

Baking soda + superglue release toxic gases, so work with caution in a well-ventilated area or outdoors. You can install a fan to prevent glue vapors from getting into the lungs, throat and eyes. In some cases, it is useful to use safety glasses to protect your eyes from exposure to adhesive fumes.

Finally, I would like to talk about several curious cases of using superglue, which, although they look, to put it mildly, ridiculous, still prove the reliability and amazing adhesive properties of this substance.

Thus, one resident of Germany, having ended up in a Spanish prison, decided not to part with his fiancee, who came to see him on a date, and asked her in advance to bring superglue for gluing car parts. The couple poured superglue onto their palms and exchanged a firm handshake. As a result, it took doctors several days to separate the lovers.

And the Mexican schoolboy did not want to go to school so much that he simply glued his hand to the headboard and still missed one day of school, during which his parents and doctors tried to unhook him.

The worst thing happened to an Englishman who became a victim of pranksters who smeared superglue on a toilet seat in one of the public toilets in London. The poor guy had to go to the hospital straight from the steel seat.

Cyanoacrylate vapor is used to detect fingerprints on objects. You can play Sherlock without leaving home: just take the cap of a plastic bottle or jar and drop a few drops of superglue on the inside surface. Now hold this “device” against glass, a mirror, or, for example, a door handle for a few seconds. The cyanoacrylate vapor reacts with the greasy print to form a solid white substance that makes the evidence visible to the naked eye. Now you can take a digital macro photo and load it into an image processing program. Having thoroughly studied the fingerprints of all household members, you can easily find out who steals yogurt from the refrigerator at night!

Superglue is a truly amazing substance, which today is the most popular and easiest to use during repairs, in industry, construction and, of course, in everyday life. The few disadvantages of superglue include the rigidity of the seam, so it cannot be used for joints that experience fracture loads, low heat resistance and inapplicability for joining polyethylene, polypropylene, silicones and Teflon. However, superglue has much more advantages and disadvantages, and companies continue to develop more and more new compositions that expand the scope of application of this legendary super-helper.

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Areas of application of superglues

Typically, cyanoacrylate-based adhesives are used where products need to be quickly glued and quickly dried, for example, when installing windows to fix seals, when attaching radio components, instrument assemblies, optics, and microcircuits. In everyday life, many radio amateurs use homemade glue based on superglue and soda: when mixing the components, the mixture instantly turns into solid “plastic” and firmly connects wiring and parts. You can use the same mixture to repair cracks, chips, and holes with your own hands.

The areas of use of superglue are varied:

• repair of shoes, leather goods;
• production of structures in dentistry, orthopedics;
• creation of jewelry;
• advertising production;
• construction;
• sewer plumbing;
• gluing rubber products;
• instrument making;
• sealing various components;
• cold welding of polymers, elastomers.

There is even medical superglue - an analogue of BF-6. It is used to seal wounds, quickly stop bleeding, and impregnate dressings. Some superglues, when applied to paper, cardboard, or other compositions containing cellulose, enter into an exothermic reaction. Therefore, on these surfaces you should first try superglue on an inconspicuous area and only then use it for work.

Areas of use

For the most part, “superglue” is used for gluing non-porous materials. First of all, cyanoacrylate adhesives are used where quick gluing is required: for rubber seals in window production, for attaching mounted radio elements, parts of components in instrument making, optical parts, microcircuits, racks, washers, mounting harnesses and individual conductors to the bases of boards, as well as for securing other elements of radio equipment. With a setting speed ranging from a few seconds to 1-3 minutes, cyanoacrylate adhesives have a second common name: “second”.

The speed and minimal toxicity of one of the cyanoacrylates (Octyl-2-cyanoacrylate) is used in surgery to seal wounds and stop bleeding. During the Vietnam War, it was used by American soldiers to provide first aid when injured, and was used as a spray can. More recently, Swedish scientists from the Royal Institute of Technology made a breakthrough in medicine; they invented “superglue” for the treatment of fractures. According to the technology of use, bone glue is applied to the fracture area and dried using a halogen lamp. When the glue dries, the bones fuse and the glue itself is absorbed into the body.

In everyday life, the amateur method of using second glue and baking soda as an epoxy composition for filling seams, cracks, and chips is often used. The mixture hardens instantly and resembles acrylic-like plastic.

If we list the areas of application of “superglue”: window production; processing of plastics, rubber, elastomers; production of toys; making jewelry; sewer plumbing; construction using metal structures; automotive industry; aircraft manufacturing; shipbuilding; leather, footwear industry; advertising industry; electrical industry; medicine, etc. - then cyanoacrylate adhesives can rightfully be called super-universal. Specifications.

Cyanoacrylate adhesives cure at room temperatures. The time for curing the glue at 20 ° C is several minutes. The curing process of the adhesive will be accelerated if there is moisture on the bonded surfaces. The “setting” time of cyanoacrylate adhesives ranges from a couple of seconds to several minutes, depending on the composition of the adhesive, the type of material being glued and the humidity of the surrounding air. Complete hardening time is 24 hours at 20 °C and air humidity of at least 55%.

Adhesives based on cyanoacrylates can easily withstand loads of 150 kg/cm2, and more advanced ones from the Irish company Loctite - 250 kg/cm2. Not long ago, “superglue” from the Loctite company entered the Guinness Book of Records by supporting the weight of two cars with a total weight of 5 tons, attached to a steel beam with nine drops of glue and lifted to a great height using a crane.

How to work correctly with cyanoacrylate superglue - procedure

Any gluing of objects with superglue can be done at home; you do not need any special skills for this. The instructions for working with it are simple, it is important to carry out all the actions quickly - there will be almost no time left to adjust the position of the parts. Only on soft, hygroscopic materials does bonding with superglue occur more slowly, and it will be possible to correct their position within 30-120 seconds.

Before bonding, large gaps and cracks must be filled with concrete dust, dry plaster or soda, and then superglue should be dropped in there - the defects will immediately be filled with a dense white acrylic-like mass. The surface should be washed and all dirt and grease removed. Acetone or alcohol can be used as a cleaner and grease remover. Next, the procedure for working with superglue is as follows:

• pierce the metal protection on the tube with the upper part of the cap;
• Apply a little superglue to a completely dry base and press the second part firmly;
• start gluing from the center to the edges, otherwise air may get inside the seam;
• press the parts for 10-30 seconds;
• leave the product to dry.

Upon completion of the work, you need to wipe the spout of the tube from the superglue and screw it tightly. Opening the bottle if the cap is stuck will be problematic, so you need to clean it carefully.

All salt is in cyanoacrylate

The main component of instant glue is a substance called cyanoacrylate. Yes, the name is complicated, but that's not the main thing. The thing is that this substance instantly hardens when in contact with liquid molecules. And here the minimum amount of water contained in the atmospheric air that we breathe is enough. If you take two objects intended for gluing and place them in a sealed transparent chamber that maintains an absolutely dry atmosphere, and then try to glue them together using instant glue, then nothing will work. The glue will simply lose its properties in such an environment. And all because the chamber maintains humidity conditions tending to zero.

Superglue solubility and safety precautions

If the superglue has thickened, you won't be able to thin it. In any case, upon contact with air, it instantly hardens. If glue gets on surfaces and materials not intended for this purpose, it is also difficult to dilute it, and there is a risk of damage to the base. Acetone or another organic solvent can be used as a means to remove superglue, but it is not always possible to clean the product. You can purchase a specialized remover; Cosmofen is rightfully considered the best. You can replace the remover with nitromethane.

When working with superglue, do not wear cotton gloves. When they are soaked, there is a risk of an exothermic reaction causing a burn. It is better to use regular rubber gloves. The room should be thoroughly ventilated: despite its low toxicity, many superglues emit an unpleasant odor. If it gets into your eyes, rinse them thoroughly with clean water and consult a doctor immediately!

What is the chemistry of the process

If you do the same procedure outside the chamber, under normal conditions, the parts will immediately stick to each other. And if a little glue leaks out, it will immediately stick to the fingers or tightly glue gloves if a person has them on his palms. This means that without the moisture contained in the air, nothing will be able to be glued together. It was this feature that was used by the engineers who designed the apparatus that produces instant adhesive.

The familiar, unpleasant feeling of glued fingers

The entire production process is carried out in an environment where air humidity is zero. That is why the glue does not glue the parts of the equipment on which it is produced, because here the main component of any instant glue, cyanoacrylate, simply does not have the opportunity to harden. Here it is, the chemistry of matter.

It is logical to assume that it is for this same reason that the glue does not stick to the tube when it is inside, because zero humidity is maintained there.

Adhesive manufacturers

Superglues are produced by almost all well-known manufacturers of such products, both foreign and domestic. Here are the most popular brands:

1. "Contact". Superglue plus primer. The product is sold complete with a primer and is intended for bonding complex and dissimilar materials, including ABS, PP, PE plastics. The primer increases the surface activity of materials, thereby increasing the adhesion of superglue. The main composition is applied to the surface after the primer has completely evaporated.
2. "Super Epoxy Moment." This superglue is two-component and does not include cyanoacrylate; instead, it contains epoxy resin. Both components (resin and hardener) are placed in convenient syringes from which they can be squeezed out in strictly measured doses. Superglue "Moment" is ideal for gluing porcelain, crystal, wood, clay products, plastic, metal, and precious stones.
3. "Super Grip." Another epoxy two-component superglue, suitable for metals and alloys, glass and ceramics, decorative and facing boards. Can be used for industrial purposes. Superglue does not shrink, is low-toxic, and can be used as a putty or sealant.
4. "Monolith". This is one of the cheapest superglues, while still having decent quality. Most often, the composition is used for shoe repair, gluing heels and soles. Superglue will reliably fasten leather, leatherette, vinyl, plastic and metal, wood and all its derivatives.
5. "Superglue 505 Universal super strong." The product hardens in 20 seconds, is absolutely transparent, suitable for all materials except Teflon, styrofoam, polypropylene and polyethylene. The disadvantage of superglue is the rigidity of the adhesive seam, which does not withstand fracture loads well. A variety of the product is “Superglue 502”, which is characterized by higher heat resistance.
6. "Master". This superglue bonds ceramics, porcelain, plastic, metal, leather, rubber, cardboard and wood. Sold in mini-packs of 3 g, as well as whole blisters containing 12 tubes/3 g.
7. "Crocs 301." Universal superglue for any materials, provides reliable bonding for a long time. Seals, fills cracks and chips. It has a very convenient applicator, protected from the composition hardening in the canal.
8. "Super Moment Pro." Reliable, long-lasting superglue, packaged in a reusable bottle with a convenient lid. Resistant to moisture, heat-resistant, suitable for all materials except very soft leather, polyethylene, polypropylene, Teflon, silicone rubber. Also, this brand of superglue is not used on glazed surfaces.
9. Loctite. A rapidly polymerizing composition based on cyanoacrylate, has a low viscosity. Superglue is intended for any materials, especially those that are difficult to glue. Its stability is less dependent on air humidity than other adhesives. The downside is the high price.
10. 5 Second Fix. Other names for glue are plastic welding, liquid plastic fixative. It has an original design in the form of a pen with a thin tip, which is equipped with a battery and an ultraviolet emitter. After applying the product, you need to shine light on it for about 5 seconds, which seriously increases the strength of the adhesive seam.
11. Wurth Klebfix. Structural adhesive for installation and repair, easy to open and close, equipped with a spill prevention system. The bottle has a dispenser, and the glue is applied strictly drop by drop. The quality of gluing with this composition is at the highest level.

Opuses about His Majesty Glue. Part two - Viva, cyanoacrylate! Viva, superglue

As I promised in the pilot “adhesive” article, we will consider adhesives gradually. In order not to procrastinate, I decided to present to your attention some facts related to my favorite, dare I say it, folk glue - cyanoacrylate “ superglue ”. In addition, to the best of my ability, I tried, within the framework of the topic of the article, to cover all the questions that readers asked in the previous part. So, if you are an active superglue user, don't miss it. The most up-to-date information about “soda + superglue”, about why superglue needs to be stored in the refrigerator and whether it is possible to light cotton wool with superglue, how to wash it off?, what glues? - everything is under the cut!

Despite the fact that, according to businesswire.com, the global market for adhesive adhesives belongs to epoxies and polyurethanes, I decided to start the story with cyanoacrylate glue. The reasons were explained at the beginning of the article.

First of all, traditionally, a short historical introduction to see the long journey of glue to our table.

History of origin

The first patent application describing cyanoacrylate was filed back in 1942. This substance was obtained by employees of the BF Goodrich Company as a result of screening materials that could be useful for the production of optical sights.

Although researchers saw that the new substance was capable of gluing together everything with which it came into contact, there was no military use for it. The developments gathered dust on the shelves until 1958, when several people from Eastman Kodak decided to create a new glue, which they called “Eastman 910”. The slowness of the market launch was explained by the fact that in the 60s technologies had not yet been developed that would allow storing and transporting glue without changing its chemical properties. In addition, the first generation of adhesives had increased fragility of the adhesive seam (which led to cracking and peeling), poorly filled gaps and had a pungent odor. In the 1960s, Eastman Kodak sold the rights to cyanoacrylate to Loctite, which in 1971, through reformulations, overcame all technical problems and released its own line of cyanoacrylate, called "Super Bonder". From that time on, the victorious march of superglue across the planet began (represented by products from Henkel, Loctite, Eastman and Permabond). By the way, Permabond still produces cyanoacrylate of the original “910” composition.

What is inside?

Cyanoacrylate adhesives are fast-acting one-component adhesives based on alkyl-2-cyanoacrylate monomers. The curing reaction of these adhesives is so fast that they are called high-speed adhesives, or superglues. The uniqueness of superglue is that it quickly and firmly bonds to various materials without requiring heating or prolonged pressure. Traditionally, the base for superglue is ethyl cyanoacrylate, but methyl (the cheapest adhesives), n-butyl, allyl, methoxyethyl and ethoxyethyl cyanoacrylates are also used.

Methyl cyanoacrylate, having a minimal molecular size, shows better adhesive properties with respect to metals and is sometimes more resistant to solvents. It is methyl cyanoacrylate that is used for gluing plastic/rubber to metal (+ fixing small adjusting screws, rivets, etc.)

Ethyl cyanoacrylate is the most common of all cyanoacrylates and the most widely used. It is best suited for bonding most plastics and elastomers and has excellent adhesion to polycarbonate, ABS, PVC and butyl rubber.

examples of the strength of some types of adhesive joints

Alkoxyethylcyanoacrylates, unlike the two brothers mentioned above, do not have a strong irritating odor and do not allow clouding of the material adjacent to the adhesive joint. However, due to their high molecular weight, these compounds cure slowly and have reduced adhesion to polymers and metals.

The curing reaction of any cyanoacrylate is an anionic polymerization initiated by any weakly alkaline components present on the surface of most materials. Continuous cross-linking in thin layers is caused by moisture adsorbed on the bonded surfaces or contained in the near-surface layers of the material (which, along with the effect of biogenic amines, explains the excellent gluing of fingers).

In the picture, the large spheres are the alkyl cyanoacrylate monomer, the small white circles are the acid stabilizer, and the dark spheres represent traces of water on the surface. When cyanoacrylate comes into contact with OH groups on the surface of the materials being bonded, the acidic stabilizer is neutralized and chains of intertwined adhesive molecules are formed, which bind the surfaces together during polymerization.

Remark about soda

The sensational method of “gluing with soda” (habra-post) is also associated with anionic polymerization. This method is suitable when using ordinary cyanoacrylate (which cures satisfactorily only in gaps of 0.05-0.1 mm, which will be mentioned below) you need to glue or splice some gaps in the material. The seam is successively filled with baking soda, which acts as a filler and an alkaline polymerizing agent, and is moistened with cyanoacrylate. The result is something like filled acrylic. In principle, you can just as successfully scrape/drill plaster from the walls; it will also provide an alkaline environment and can act as a filler. This method is good for porous materials with which individual glue does not work well (approx. without adding special polymerization enhancers, more on them below). The reaction, depending on the glue, can proceed exothermically (with the release of heat) and sometimes release vapors that are best not inhaled (for toxicity, see the end of the article). By the way, about “plaster instead of soda”. There is an industrially produced adhesive under the brand name “SupaFix”, which uses calcium oxide as a polymerization accelerator (the same quicklime that our builders (RB so accurately, “I guarantee it”) are trying to replace cement in plasters). The glue joint is actually made of stone, so strong that they are even recommended to seal cracks in concrete.

The rate of cure of cyanoacrylate, if left exposed at the surface, will be relatively slow (several hours) because there is not enough moisture (although the cyanoacrylate will cure at the interface)

When the adhesive is placed between two close-fitting surfaces, moisture is introduced to both surfaces and the cyanoacrylate quickly cures. Therefore, it is the level of humidity and the gap between the bonded surfaces that are the main factors affecting the curing speed. Optimal curing conditions for cyanoacrylates are 40% to 60% relative humidity. Low humidity, such as 20%, will lead to slow curing, and high relative humidity, such as 80%, on the one hand will polymerize the adhesive faster, but on the other hand, it will turn the adhesive into a piece of inert polymer before it has time to stick to the surface being bonded ( which means that a glue seam will not work).

How to prepare superglue for future use

Cyanoacrylate adhesives have a short shelf life - about one year from the date of manufacture, if unopened, and one month after opening. This, unlike the evaporation of the solvent in other types of glue, is due to the same sluggish anionic polymerization with the participation of water vapor in the air. Therefore, in production, glue is kept in a dry atmosphere. Therefore, to extend the life of your favorite open tube, follow these recommendations:

• Store opened cyanoacrylate adhesive in an airtight container with as many silica gel desiccant packets as possible. These bags are often placed in packaging with new shoes, Chinese electronics, etc.

• Plug the hole in the glue supply tube with a needle from a disposable syringe. After using the glue, the residue will clog the needle and block the access to moisture. To open the glue if necessary, just heat the needle with a lighter. Polymerized cyanoacrylate, a typical thermoplastic like plexiglass, will float and “open the floodgate.” As for the tips to store superglue in the refrigerator/freezer. This certainly makes sense, because since the main cause of polymerization is liquid and gaseous water, it is a good idea to place the glue where the water will be solid - in a freezer with a temperature below 0 °C (32 °F; 273 K) - and stop the polymerization reaction completely. But there is one BUT here. At some point, the glue will have to be removed from the refrigerator, and moving from cold to hot will lead to the formation of condensation and will produce so much water that it will not seem like enough. Conclusion - it makes sense to store only a sealed tube in the cold. If the tube is opened, please ensure smooth step-by-step defrosting (NOFROST, etc.). The question may arise: why store a sealed tube if the sealed packaging itself prevents moisture from getting into the glue. The point here is that during the storage process the so-called aging of cyanoacrylates, as a result of which they become thicker, viscosity increases, up to turning into stone (+ slow hydrolysis with the formation of cyanoacrylic acid). Cold (below -18 °C) stops these processes almost completely and the glue can be stored indefinitely. By the way, thickened, old cyanoacrylate can be diluted with a fresher and liquid glue, similar in composition (= the same brand) and return all the properties.

The gap between the parts to be glued should ideally be less than 0.1mm, and the smaller the gap, the faster the cure. Typically, thin gaps produce the strongest seams. Although some varieties of cyanoacrylate allow you to fill gaps up to 0.5 mm, UV-curable ones even bridge gaps up to 5-6 mm.

The strength of the adhesive seam increases over time. As a rule, cyanoacrylates acquire sufficient strength within the first minute of gluing:

But this process does not stop over the next 24 hours and in some cases can double the strength. So, depending on the importance of the parts being glued, it does not always make sense to immediately use them in everyday life. Cyanoacrylate should not be subjected to physical stress during the critical polymerization time, since a damaged adhesive joint will no longer be able to fully regain its strength.

Cured polyalkyl cyanoacrylate is a pure thermoplastic very similar to plexiglass (PMMA). Individual physical properties depend on the chemical nature of the ether chain. The table summarizes all the pros and cons of cyanoacrylates.

As you can see, there are more disadvantages. To get rid of them, pure cyanoacrylates have to be modified with various additives. Commercial adhesives consist of pure monomer with relatively small amounts of additives, which mainly improve the rheological characteristics of the product (viscosity, etc.). A typical composition for cyanoacrylate adhesive contains 88% cyanoacrylate monomer, 9% thickener (e.g. PMMA, cellulose ethers, rubbers, etc.), 3% rheology modifier (colloidal silica) and 0.02-0.03% acid or radical stabilizer. All functional additives can be divided into two main groups:

1. additives that modify the polymerization process
2. additives that change the properties of the final polymer.

Modifiers of the polymerization process include stabilizers. Their responsibility is to ensure a balance between the stability (lifespan) of the adhesive and the speed of cure. For this purpose, substances that inhibit polymerization are used, most often acidic compounds (in concentrations from 5 to 100 ppm): SO2, sulfonamides, SO3, sulfonic acids, sulfones, cation exchange resins, boric acid chelates. Free radical polymerization inhibitors such as hydroquinone or sterically hindered phenols can also be used.

In contrast to the effect of stabilizers, the purpose of the so-called. accelerators - increasing the rate of polymerization. One of the disadvantages of the first generation of cyanoacrylate adhesives was that these adhesives could not bond porous materials such as paper, wood/cork and leather. The reason for this was that the low viscosity adhesive was absorbed into the porous substrate before polymerization occurred. Moreover, simply thickening the glue did not give any effect. As a result, a solution was found - substances that are capable of binding alkali metal cations. Interestingly, the mechanism by which accelerators function is unclear, but practical effectiveness has been proven in practice. Examples of compounds used as accelerators are crown ethers, polyalkylene oxides and calixarenes.

In addition to porous materials that absorb glue before it dries, there are materials that have an acidic surface (for example, many fabrics). Because of this, curing may take weeks or may never take place. In this case, accelerators based on crown ethers are also used. Reader sappience also mentioned the so-called. foam-safe-cyanoacrylate, which are used in aircraft modeling and do not damage polystyrene foam (foam, styrofoam, EPS, XPS), but also cost much more than classic superglue. Here, the principle of operation of additives is similar to that described above for fabrics and porous materials (the principle “polymerizes, the foam cannot be destroyed” works - by analogy with the well-known, execution cannot be pardoned).

Most of the second group of additives that change the properties of the final polymer make it possible to obtain cyanoacrylate adhesives with special functional properties. A few words about each in order of priority. I have already spoken about “surface-insensitive” adhesives. Standard ethyl cyanoacrylate adhesives based on ethyl 2-cyanoacrylate (can be methyl and blah blah blah), these are adhesives that contain only a thickener (one of those described earlier) as functional additives. The remaining additives for the most part solve some of the disadvantages of cyanoacrylates mentioned above.

Disadvantage: low impact strength. The solution to this problem makes it possible to create high-strength (impact-resistant) cyanoacrylate adhesives that have significantly increased impact strength (and low peelability) due to the inclusion of elastomers (ABS or MBS) in the adhesive composition, which form separable phases during curing.

The elastomer particles minimize crack propagation by allowing the crack to reach the rubber particle, which takes the brunt of the impact and dissipates the stress. These adhesives are particularly suitable for joining rubber to metal. One of the disadvantages of high-strength cyanoacrylates is their reduced curing speed. I would like to separately note that there are works that describe the use of citric acid as an additive to classic ethyl cyanoacrylate, which can significantly increase the impact resistance of the adhesive when connecting metal to metal (for example, aluminum to aluminum).

Disadvantage: fragile adhesive seam. The answer to this shortcoming was the development of flexible adhesives. These cyanoacrylates have been specially developed for attaching speaker cones to speakers. Plasticizers based on aliphatic esters of carboxylic (oxalic, tartaric, citric) acids made it possible to achieve flexibility. The resulting adhesive joint does not degrade over time and remains plastic indefinitely. Such adhesives are used for gluing leather products, fabrics, etc. materials (including those with an acidic surface nature). Disadvantages: low heat resistance (max 75 °C)

Disadvantage: clouding of the seam, formation of whitish streaks. It is known that when cyanoacrylates are used, there is a tendency for monomer vapor to polymerize on the surface adjacent to the adhesive joint. As a result, white clouding streaks form. For cases where the formation of such a defect is unacceptable, adhesives based on methoxyethylcyanoacrylate or ethoxyethylcyanoacrylate (or mixtures thereof) with low vapor pressure are used. Materials with heavier hydrocarbon residues (hexyl-/octyl-) are not used due to the increased softness of the adhesive joint and the high cost of such glue. Another advantage of “non-clouding” adhesives is the absence of a strong odor.

Disadvantage: inability to glue “fat” plastics (PE, PP, PTFE). Although for each case of working with cyanoacrylates, preliminary surface preparation is recommended

which is

for metal - surface degreasing and sandblasting, for polymers - solvent cleaning and optional surface grinding, for glass and ceramics - surface cleaning and drying.

however, there are materials that, due to their low surface energy, are almost impossible to bond with cyanoacrylates. These are all polyolefins and fluoroplastics (and the “acidic” surfaces mentioned above). To eliminate this injustice, primers are used in the form of a diluted solution of alkylamines (stearylamine (SA), distearylamine (DSA), dimethylstearylamine (DMSA) and distearylmethylamine (DSMA)) in a low-boiling solvent. The effect of the chemical nature of the primer on the adhesion of cyanoacrylate to polypropylene is shown below.

When the solvent evaporates, gluing is carried out in the traditional way. In addition to alkylamines, some quaternary ammonium salts and phosphines can be used with approximately equal effectiveness. Along the way, we can also mention adhesion enhancers to metals, which are carboxylic acids and their anhydrides.

Note: this thing will not work with fluoroplastic (~Teflon). Primers have not yet been invented. The only option is etching the surface. This can be done, as jar_ohty mentioned, using “... sodium. Either a solution in ammonia, or a solution in THF with naphthalene, or a melt. Fluoroplastic reacts with sodium and becomes covered with a black layer, to which everything can be glued with any suitable glue. Another option is potassium permanganate with perchloric acid. 500 g of water, 80 g of potassium permanganate, 180 g of perchloric acid, temperature 80-100°C, processing time 15-20 minutes. But the result is worse than with sodium

«.

In order not to bother with nuclear chemical reagents, you can immediately purchase a ready-made Tetra-Etch etching solution. Due to the oxidation of the Teflon surface, its wettability with glue sharply increases (+ the surface becomes much rougher). The adhesion between etched and untreated fluoroplastic differs by almost 10 times. So... A little life hack. During chemical etching, the surface of the fluoroplastic turns black. This effect is removed with a solution of sodium hypochlorite.

Disadvantage: Fast curing only in a thin layer. As already mentioned at the very beginning of the article, gluing with cyanoacrylate gives the best results in a thin layer (<0.2 mm). For wide cracks you need to either use fillers (like soda/"plaster" CaO) or look for another glue. But everything changed with the development of UV-curable adhesives with photoinitiator additives that absorb ultraviolet light in the UVA region (about 365 nm). Light-curing cyanoacrylates cure to a solid state in less than 3 seconds when exposed to high-intensity ultraviolet light. UV-curable cyanoacrylates can cure to depths of up to 5mm or 6mm when exposed to a light source of appropriate intensity. The adhesive, applied to areas not exposed to light, cures using a traditional mechanism.

Disadvantage: low heat resistance. Cured cyanoacrylate, as I already mentioned, is essentially ordinary thermoplastic PMMA. It is therefore not surprising that, for example, the maximum operating temperature of standard ethyl cyanoacrylate is from 85 °C to 100 °C, and the bond strength tends to drop rapidly after reaching a temperature of 100 °C. Most polymer cyanoacrylates begin to thermally decompose at temperatures approaching 140 °C. A guideline can be the glass transition temperature, above which the polymer softens and floats. Naturally, we can no longer talk about any strength. Some approximate figures in the table below:

This also includes the aging of the adhesive joint at elevated temperatures. The saddest thing is that this problem has not yet been solved and there is no heat-resistant cyanoacrylate, no matter what anyone says about using superglue as a hot-melt adhesive. In the case of bonding metals with ethyl cyanoacrylate, a rapid decrease in joint strength is observed at temperatures above 100 °C. Bond strength gradually decreases over two days of aging at 120 °C and eventually stops at zero. Some authors suggest using maleimide and bismaleimide resins, maleic anhydride, phthalic and benzophenonetetracarbonic dianhydrides as additives that increase thermal stability. Others predict the future of alkyl-2-cyanopentadienoates as the main heat stabilizer of superglue. But there are no commercial products; anyone who has the opportunity can test it at home.

Disadvantage: low moisture resistance. The moisture resistance of joints created using cyanoacrylate adhesives on metals and glass leaves much to be desired. It is well known that polycyanoacrylates are susceptible to hydrolysis in the presence of moisture. This decomposition is very noticeable at pH above 7. Additionally, on metal substrates, corrosion products can accelerate this hydrolysis process. Hydrophobic additives, such as fluorinated cyanoacrylates and silane binders, can help. No cyanoacrylate manufacturer has yet produced an adhesive that has improved moisture resistance, but it is well known that heat-resistant products containing anhydrides (see above) also exhibit improved moisture resistance. NB , in general, to obtain a highly water-resistant adhesive joint, propyl cyanoacrylate is used, which is significantly more expensive.

Let's add some fun facts...

Superglue as medical glue

Due to their speed of cure and ability to degrade by hydrolysis, cyanoacrylates can act as an alternative to surgical suturing. Many have heard that superglue was actively used during the Vietnam War to glue wounds together in conditions of lack of time for more serious surgical intervention (with the obligatory subsequent delivery of the poor wounded to the hospital). Well, in general, using glue takes less time to close the wound, there is less chance of infection (suture channels form additional paths of contamination), and, finally, the cosmetic appearance is better. For superficial damage, IMHO, our medical BF is better (note from denisgrim: “medical BF glue is more likely not a glue, but a film former. It cannot be applied to an unwashed, contaminated wound - the infection will seal and there will be suppuration”). But there is one nuance here: ethyl cyanoacrylate, sold in every stall, is not used as a medical glue. For this purpose, more expensive and rare butyl or octyl cyanoacrylate is used (Dermabond, approved by the FDA in 1998, there is also SurgiSeal). Surgical n-butyl cyanoacrylate is sold under the brands Indermil, GluStitch, GluSeal, PeriAcryl, LiquiBand (IDtmtm also mentioned domestic Sulfacrylate with a comparable price tag). And there is no “Globus glue” there. Below is a useful comparison chart.

We read about the incomprehensible activated partial thromboplastin time (APTT) here.

Regarding the metabolism of cyanoacrylates biodegradation, there is no clear consensus regarding tissue toxicity. If only because the decomposition products can become potentially toxic depending on the decomposition environment. Degradation of cyanoacrylate occurs as a result of the destruction of the polymer backbone, often the presence of water can cause hydrolysis of cyanoacrylate to form formaldehyde and alkyl cyanoacetate. That is why, despite FDA approval for topical use in the case of wounds, there is still no consensus on other areas of application (cardio, etc.).

About the toxicity of vapors. Cyanoacrylate vapors, i.e. The gaseous monomer (the same one that polymerizes and forms white stains on plastics) irritates the sensitive mucous membranes of the respiratory tract (eyes, nose, throat, lungs). True, they quickly polymerize with moisture in the membranes and become inert. But in general, it is better to minimize possible unpleasant consequences and work with cyanoacrylate glue in well-ventilated areas. Superglue can cause an allergic reaction in some people if it comes into contact with the skin. And about 5% of people may even get a “cyanoacrylate cold” (= allergic rhinitis), with flu-like symptoms.

"Burning" superglue

The use of cyanoacrylates to bond certain natural materials such as cotton (jeans, cotton swabs, cotton balls, some yarns or fabrics) or wool may result in an exothermic reaction. The heat generated may cause burns or poison the experimenter with irritating white smoke. But it is important that the glue is pure cyanoacrylate, without any additives (Permabond 910″), otherwise a spectacular trick will not work. See explanation below (clickable).

Superglue in forensics - for taking fingerprints
Comment from spiritus_sancti: for completeness, it’s worth adding about cyanoacrylate cameras. to search for fingerprints on dark, porous surfaces - the object is suspended in a chamber where superglue is spilled, and its vapors, reacting with traces of discharge from the fingers, produce whitish traces of fingerprints (however, many have seen this on the packaging of superglue left in closed containers). For forensic science, this became a mini-revolution, making it possible to find prints on complex surfaces, and not just with powder on smooth ones.

Is there hard superglue?

This kind of thing really does happen. And it is a solid substance that, when heated (just above room temperature), liquefies and turns into glue. As far as I know, caprolactone acts as a solid state former.

How to remove superglue?

It is important to know which type of cyanoacrylate needs to be washed off. Methyl cyanoacrylate (the basis of the most common and cheap adhesives) dissolves slowly in water. Ethyl cyanoacrylate does not dissolve in water, ethanol and many other substances, but, on the contrary, instantly hardens in places of contact with them. Cyanoacrylates dissolve well under the influence of concentrated dimethyl sulfoxide (DMSO, the drug "Dimexide" in the nearest pharmacy), using a glue remover "Secunda" based on propylene carbonate; many foreign cyanoacrylate removers contain nitromethane. There are mentions that superglue was washed off with acetonitrile or γ-butyrolactone (but it was most likely washed off by DEA workers).

An alternative take on peeling/rinsing from Snarky reader

How to unstick what is glued?

Gluing is half the battle, the most interesting part is unsticking

In my hobby - radio-controlled cars - rubber is glued to plastic disks with cyanoacrylate adhesives. As in any sport, tire consumption is high - one competition can take up to 3-5 sets of 4 pieces. Accordingly, if rubber is a consumable material, then the wheels can be used repeatedly if you somehow remove the glued tires from them. What has not been tried over the many years of this hobby?

1. Dimexide . It literally doesn’t work at all, I don’t know a single person, either here or abroad, who would use this method more than once (to try). It didn't work out for me either. 2. Thermal method . Baking in the oven, boiling in a saucepan or using pressure cookers. The method works, but is very time-consuming and associated with odor, pollution, etc... In addition, the physical impossibility of achieving a temperature above 100C at normal atmospheric pressure requires a long process. Using pressure cookers speeds up the process. Used by a large number of people. At one time, for this purpose, I purchased a multicooker - a pressure cooker with electronic control, which makes the process simple and fast - no more than 15-20 minutes at 145C 3. Acetone . The most common, simple and convenient way. The items to be unstuck are placed in a large plastic bucket or other hermetically sealed container, acetone is poured into the container (no more than 1/10 of the volume) and... And that’s it. The container is closed and left for 12-24 hours. After this time, everything is glued down, the discs can be removed and reused. Acetone can also be used repeatedly.

Addition 1: at the request of readers - a comparative table of manufacturers/brands of cyanoacrylate adhesives. There are no Russian packers here, as they are in no hurry to talk about their product. Attention! There is a huge picture under the spoiler.

World brands of cyanoacrylate glue. Pivot table

Table Legend:
LSS : Shear Strength TS : Tensile Strength SG : Specific Gravity (density relative to the density of water). Gap Filling : The maximum gap that liquid adhesive can fill, in mm. Refractive Index : an indicator of interest when gluing transparent plastics and glass. Cure Time (sec) : Initial cure time to achieve standard joint strength. Maximum strength occurs after approximately 24 hours (see article).

Addendum 2: Table of radiation resistance of various adhesives (at the request of mphys)

NB the first part of the “glue series” - Opuses about His Majesty Glue. Part one - introductory And further: Opuses about His Majesty Glue. Part three - polyurethane vs cosmic cold Opuses about His Majesty Glue. Part four - silicones

Whether there will be a next article depends on the habra community, because subj.

ps all updates and intermediate notes from which habra articles are then smoothly formed can now be seen in my telegram channel
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Used sources

Dean J (1985), Lange's Handbook of Chemistry, McGraw Hill, New York. Drain KF, Guthrie J, Hung C, Martin F and Otterburn M (1984), 'Effect of moisture on the strength of steel-steel cyanoacrylate adhesive bonds', J. Adhesion, 17(1), 71-81 Grant E (1983 ), Drop by Drop: The Loctite Story, Loctite Corporation, Newington, CT. Klemarczyk P and Okamoto Y (1993), 'Primers for bonding polyolefin substrates with alkyl cyanoacrylate adhesive', J. Adhesion, 40, 81-91 Lee H (1986), Cyanoacrylate Resins - The Instant Adhesives, Pasadena Technology Press, Los Angeles. Rich R (1994), 'Anaerobic adhesives', in Handbook of Adhesive Technology, Pizzi A and Mittal K (eds), Marcel Dekker, New York, 467-79.

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Tips and tricks

In original packaging, products are stored for 6-12 months, depending on the specific brand. Cheap superglues usually harden quickly after the first use, and there is no point in storing a started tube. To extend the shelf life, you can put the tightly closed bottle in the refrigerator.

It happens that superglue gets on the skin, and it can be quite difficult to remove stains. This phenomenon does not pose a danger, so you can calmly wash your hands several times with warm water and soap. If you need to cleanse your skin urgently, you should use Dimexide diluted twice with water, a soda solution, alcohol, and vegetable oil. Superglues are inexpensive and reliable helpers in the home; with their help, you can repair any product in a short time without much time or financial investment!