The process of covering the inside of a car glass with a thick film that provides protection and strength is called glass armor. This coating can withstand hammer, bat and other heavy objects. The booking system itself came from business. The earliest films were invented for industrial buildings and commercial premises where protection from burglars and vandals is needed. From this article you will learn how to apply such a film yourself, what advantages and disadvantages this system has and how effective it is.

Varieties of film

There are different types of armor films designed for:

• Auto glass. Thickness from 250 to 310 microns. Free sale. It is glued according to the tinting principle. It will take 1 month to dry completely. After that, the film withstands impacts with a stone, hammer, bat. He saves a car and its passengers both from stones that can fly off on the highway, and he also saves robberies.
• Office buildings. Same thickness as auto glass film. Suitable for offices, shop windows, workshops, large shopping centers. The rolls of material are much wider than for auto glass.
• Especially important objects. The thickness is about 550 microns. This is necessary for especially important facilities in any state in order to protect against possible terrorists. Such glass is absolutely impossible to break and penetrate into the room.
• Bulletproof for auto glass. Withstands shooting from not all firearms. Standard film is bulletproof and can withstand 38 caliber bullets from a pistol. The thickness of the glass must be at least 12 mm, as well as multi-layered, exactly like the windshield of a car. The machines, this booking will not be able to stand.

Whatever the booking film, it is difficult to give a 100% guarantee of durability. The name "bulletproof" is arbitrary. Studies have shown that this glass will not break if they shoot from a pistol of the specified caliber and in different parts of the glass. In the event that bullets of the required caliber hit the same place, the glass will be pierced through and no film can save it.

Pros and cons of booking a windshield with a film

Often, car enthusiasts believe that car tinting and booking are related to each other. In addition, it is believed that such a coating on the windshield will impair visibility and interfere with driving. All this is completely wrong. The main features and advantages of such a film:

• High-quality visibility;
• Does not mix with tinting;
• Perfectly tolerates autochemistry;
• Thick film covers the windshield, thin film covers the rest;
• Polarized film coating - glare reduction;
• Uniform distribution of impact;
• Protection against minor vandalism.

It is also worth remembering about the headlights, which also need protection from foreign objects.

Before you go to the service station, it is important to know the disadvantages of booking with film:

• When driving or parking, dust settles on the surface of the windshield. When the car owner turns on the wipers, significant scratch damage is applied to the film. To minimize damage, avoid excessive dust and wipe the windshield more frequently.
• Bubbles can occur anywhere. If they appear in front of the driver's eyes, he, as a rule, will be very annoying and reduce the quality of visibility. In addition, the appearance of the car suffers.

The price of booking car windows with a film with darkening starts at around 3,500 rubles.

DIY booking

Glass armor is usually used by motorists who have become victims of broken glass for any reason: someone because of stones that often fly off the wheels, and someone because of a robbery.

The appearance of the film is similar to the tinted one with the highest level of transparency. You can buy it in auto stores or online stores. The procedure for applying the film is as follows.

1. It is necessary to remove the side windows. You must follow the instructions based on the make and model of your machine. You should carefully get to the clips and remove the glass, before that, do not forget to unfold the door cards.

2. Removal of dirt and grease. An important point is to completely degrease each glass. To do this, lay the glass on a pre-cleaned flat surface. Watch out for abrasive particles that can scratch the glass. Next, you should clean the inside of the side glass, where the booking film will be applied. To clean, you can use a special glass detergent and a lint-free napkin. It is important to understand that any dust or lint, if it suddenly remains on the surface of the glass, will not completely remain under the film, and the look of the glass from the inside of the cabin will be far from aesthetic.

3. Preparation. The film itself consists of an adhesive layer and a colorless protective backing. First, measure the glasses and cut off the required amount of film with a margin.

4. Now apply to the clean inside of the glass. The film must be positioned so that the backing is at the bottom. Using masking tape, you can perfectly fix the film on the glass. Make sure that the film peeks out at least 1 cm from all sides.

5. Preparation of a special agent for removing the adhesive part from the film. For preparation, you need to take plain water and liquid soap. Proportion of 20% soap and 80% water. Use shampoo with minimal fragrances and additives. Otherwise, these additives are more likely to enter into a chemical reaction with the adhesive layer than this will turn out to be unknown. The resulting solution must be filled with a garden sprayer.

6. Glue the film and smooth it. Carefully remove the protective backing, holding the foam only where the edges will not come into contact with the glass. Pour the prepared solution over the glass surface and the adhesive layer of the film. Now you should apply the armored film with the sticky side to the inside of the side glass. On the first, the film will travel over the surface, this is necessary to smooth out irregularities using a special mini-spatula (you can change it to a bank card). With simple movements from the center to the edges, it is necessary to expel all air bubbles. If this is not done, then bubbles will form, which will no longer be possible to remove.

7. Drying with a building hair dryer. After the entire film has been straightened, it must be thoroughly dried with a hairdryer. It has a high air t and a thinner jet. The hot film will stretch over the surface. Then take a break for an hour so that the film has time to cool.

8. Removing excess. Initially, at least 1 cm of excess was left in order for the film to be enough. Now that it has settled well and cooled down, you can cut off excess parts with a clerical knife. It is best to hold the knife at a 45 degree angle. It is also advisable to hold the film with a spatula.

Final drying takes more than one day. The highest degree of protection will appear in a month. Based on experiments, it is possible to break through glass only with 4-5 blows in one place with a heavy object.

Reservation of car windows with film (video)

Outcome

Thus, the armoring of car windows with a film very well protects not only from foreign objects flying from under the wheels, but also from possible robbers and vandals. But, as a rule, car owners begin to think about it only when something like this happens and the glass is damaged.

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Armored windows or how to secure your home in the 21st century

Armored windows for the house are already beginning to cease to be something unique and inaccessible. Today's realities show that only with their installation can you gain confidence in the absolute protection of your own home. It's 2016 on the street, and if you do not want to become a victim of modern-day offenders, then you need to keep up with the times and be aware of the latest security methods. I will try to provide you with enough information for this.

Armoring against bars

The owners of window grilles can answer that, they say, they have already taken enough care of the safety of their homes, and they do not need expensive window armor at all. Then I recommend that you pay attention to the significant disadvantages of using steel barriers, which are deprived of armored glass:

1. The presence of vulnerabilities when trying to hack... As I mentioned above, today it is the 21st century in the yard and attackers have in their arsenal not only a crowbar and a set of master keys. For example, liquid nitrogen can be used to remove steel rods, with the help of which the task will be solved quickly and silently;

1. Lack of protection against bullets... The metal mesh construction will not stop bullets or small debris. And you never know what can happen on the street? Recent tragic events in Europe have demonstrated that even the most affluent areas can be at the epicenter of a situation with the use of firearms and explosives;

1. Violation of the panoramic view... Even beautiful forged products cannot completely eliminate the oppressive feeling of the sky enclosed by steel;

1. Reducing the level of fire safety... Deaf gratings not only do not let anyone in, but also do not let anyone out, which can play a fatal role in the event of a fire or other emergency. And even if a swing-type construction with a lock is used, then, again, precious seconds, or even minutes, will also be spent on the search for the key.

The price of armored windows, although much higher than forged or lattice, but they are:

• Not susceptible to hacking methods available to most robbers;
• Protect not only from penetration, but also from bullets, and from shrapnel;

• Will not affect the panoramic view in any way, since they have absolute transparency;

• Will not become an obstacle if necessary, an urgent exit through the window opening.

As you can see, the differences are very significant in order to think about the possibility of allocating a sufficient amount of funds for the purchase and installation of armored double-glazed windows.

Booking options

There are two ways:

1. Purchase and installation armored glass unit;
2. Window glass reservation special film.

The first is undoubtedly more reliable and allows you to achieve maximum security, while the second, on the other hand, will cost less and can even be done by hand, although the process itself is quite complicated. I will analyze both:

Armored glass unit

To ensure the absolute inaccessibility of your window opening, of course, it is necessary to install a fully armored window, that is, not to be limited to strengthening the strength of the glass alone, but to guarantee the resistance to mechanical stress of the frame itself.

Thus, we can talk about two components of the entire structure:

1. Laminated glass reinforced with polyvinyl butyral film or polymer filling;

1. Frame made of multi-chamber profile with hardened steel inserts... In this case, the appearance of the window is the same as that of a regular one.

When buying such a miracle of modern technologies, ask how protected the joints of the frame with the glass, since in this design they are the most vulnerable spots and should be covered by the "filling" of the profiles. Otherwise, the level of protection of the entire glass unit can be considered incomplete.

Previously, glasses were reinforced exclusively by pouring polymers between them, now the use of PVB films is becoming more widespread. Why? To answer this question, it is enough to make a comparative description of some parameters of finished products:

1. Chromaticity:

• • With PVB, complete transparency is guaranteed without the appearance of any shades for ten years;
  • When pouring polymers, yellowness may appear already in the first operational year as a result of exposure to ultraviolet radiation;

1. Optical distortion:

• When PVB is completely absent;
• When pouring polymers, it is possible if the substance is unevenly distributed;

1. Layering:

• With PVB, it is completely absent;
• When pouring, over time, it occurs due to a weak level of adhesion between polymers and glass;

1. Loss of protective functions:

• With PVB, at least ten years from the start of operation does not occur;
• When pouring, it is gradually carried out;

1. Increase in thickness:

• With PVB, the minimum;
• Perceptible when pouring.

As a result, I concluded for myself that if I order bulletproof glasses, then only those that are reinforced with polyvinyl butyral film. The cost of such double-glazed windows depends primarily on the protection class:

• 2nd class:

• 3rd class:

• 5th grade:

• Class 5a:

• 6th grade:

• Class 6a:

Glass armoring with foil

Reserving windows with foil, as I noted above, is much cheaper. So, for example, if you order such a service from the appropriate company, then everything with work will cost you from 1000 rubles per square meter, which is many times cheaper than installing armored double-glazed windows. Such a barrier, of course, will not save you from snipers, but from burglary and even fragments completely.

Here is a classification that demonstrates the level of this method of protection, taking into account the thickness of the glass, as well as the thickness and number of film layers:

The armored film on the window panes can be installed by yourself. The task at first glance does not seem very difficult, but in fact it has many "pitfalls", for successful overcoming of which you need to have at least some experience.

If you have doubts about whether you can cope with booking glass on your own or not, then it is better to seek help from qualified specialists, or at least to begin with, practice on a small window somewhere in the closet or garage.
Otherwise, you run the risk of simply spoiling the applied material itself, the cost of which starts from three hundred rubles per 1 m 2, and the processed glass unit, which will cause your family budget much more damage than paying for hired services.

The very same instruction for booking glass, which I used, looks like this:

1. Measured the glass using a tape measure. I added 10 mm to the data obtained on each side for cutting, but if you have them without a frame, then 5 mm will be enough;

1. Made calculations in relation to a roll, the standard width of which is 1524 mm;
2. On the big table made precise cutting canvases;
3. Prepared the solution by adding a few drops of shampoo to half a liter of distilled water;
4. Attached the cut film fragments to the glass by checking the compliance. In case of a positive result, proceeded to further operations;
5. I applied the mixed solution to the glass and thoroughly cleaned it out of dirt with a scraper, after which he removed the remnants of foreign particles from the smooth surface with a special wash;

1. I repeated the procedure several times, achieving absolute cleanliness. The fact is that getting the smallest grain into the gap between the film and the glass can ruin the whole work;
2. Moistened the first fragment of the coating on both sides to prevent dust from getting on the adhesive layer and removed the lavsan from it;
3. Then again applied the solution to the side with glue and applied it to the glass;
4. The outer side was also treated with the prepared liquid, after which with a yellow squeegee, I drove all the water out from under the film;

1. Trim excess edges with a sharp knife;
2. Removed leftovers;
3. He left the coating to dry. During this period, the film and glass are so strongly bonded at the molecular level that they become one whole.

Depending on the thickness of the applied material, the time of its complete drying also changes:

Conclusion

Metal, wooden and even plastic armored windows will become a reliable guarantee of its safety for your home. If their cost is too high for your family budget, then you can stop at booking glass by applying a special protective film. It will come out much cheaper and will also provide a decent level of protection.

The video in this article contains additional information related to the topic discussed. If you have any additional questions, then ask them in the comments.

In preparing the article, material was used from the site roststeklo.ru

Bulletproof glass- a multilayer structure consisting of several M1 glasses and several layers of a polymer photocurable composition. Depending on the required protection class, the design can be either with or without a film. This structure provides protection against bullets fired from different types of weapons, depending on the required protection class.

The design of the bulletproof glass is transparent and provides protection in classes B1, B2, B3, B4, B5 (1, 2, 3, 4 and 5 bullet resistance class) in accordance with GOST R 51136-2008, while simultaneously transmitting light. Suitable for both internal and external glazing.

It is possible to complete a double-glazed window to maintain the temperature regime.

Bulletproof glass- a guarantee of security, it was created in order to protect people and their property. That is why it is especially important that the glass is of excellent quality. You need to be sure that you and your property are fully protected. The first, second, third, fourth, fifth or sixth protection class of bulletproof glass is chosen based on the conditions and wishes of the customer.

Scope of use of bulletproof glass

• currency exchange offices;
• places for issuing money at the cash desks of large organizations, enterprises;
• internal security posts in banks, jewelry stores, shooting galleries;
• workplaces of operators of gas stations;
• workplaces of bank tellers working in operating rooms;
• workplaces of employees of the duty units of the internal affairs bodies;
• equipment for banks and cash collection machines;
• other buildings, structures and objects that need to be protected from burglary, strikes and shelling.

Double-glazed windows made of laminated armored glass, made using mirrored, tinted glasses of various colors, have unique properties that provide not only protection of the room from impacts and shelling, but also reduce heat loss in the cold season, protect from the harmful effects of sunlight and noise.

A mirror made of laminated glass, along with high strength characteristics and aesthetic properties, ensures its long-term and safe use in rooms with high humidity (in bathrooms and swimming pools).

Armored laminated protective glass (bulletproof glass) is intended for use in vehicles, in administrative and residential buildings, where there is a need to protect human life and material values.

Bulletproof glass characteristics

Specifications bulletproof glass comply with GOST R 51136-2008 "Multilayer protective glasses". The total light transmission of glass is at least 70%. The glass must be heat and moisture resistant, withstand a temperature of 60 ° C and a humidity of 95%. Its frost resistance is minus 40 ° С.

Defensive ability bulletproof glass depends on its thickness. The glass is 37 mm thick and stops the 7.62 mm PS-43 bullets from the AKM. According to the certificate issued by the State Standard of Russia, such glass corresponds to the third class of protection and, in addition, is able to detain bullets from pistols PM, TT, AK-74 assault rifle and fragments from hand grenades RGD-5, F-1 and RG-42.

Bulletproof glass has protective properties

• withstands multiple impacts of a freely falling body;
• resistant to penetration;
• withstands the impact of firearms (pistols PM, TT, AKM machine gun, SVD rifle) and prevents through penetration of the damaging element.

Armored glass production technologies

For the manufacture of bulletproof glass, flat or bent polished workpieces with a thickness of 5 to 10 mm are used. In order to increase their strength, they are glued together in a certain combination. Polyvinyl butyral film is used as bonding material. Then a layer is glued to the inner surface of the glass, which protects against damage by secondary glass fragments. Thus, you get not only extremely durable, but also shatterproof glass.

Protective film in armored glass

The protective film has a very high transverse tensile strength. When applied to glass, it gives it the same properties: it greatly weakens deformations transverse to the glass surface, including microvibrations. When even a small lateral deflection occurs, the viscous polymer film quickly returns the glass (providing elastic deformations) to its normal position. Of course, a sufficiently strong impact can deflect the glass with the film from its undeformed position to the distance necessary for the fragile glass to break. But at the same time, it remains in place, glued to the protective film.

Properties of a protective film of bulletproof glass

• strengthening the glass - if the impact is not too strong, the glass does not break (when struck by a soft body, foot, stone or bottle);
• shatterproof - the film prevents fragments from entering the room even when the glass does break (therefore, the protective film is applied to the armored windows from the back side);
• protection against penetration - maintaining the integrity of the window (even after breaking) prevents an intruder from entering the room, providing protection similar to gratings;
• the possibility of listening by removing sound vibrations from the glass with special equipment is almost completely excluded;
• sound insulating properties (sound enters the room through the window due to mechanical vibrations of the glass, which repeats street noise);
• absorbs ultraviolet light well, keeping the interior from fading and providing protection against one of the types of heat transfer. As a result, the thermal isolation of the room from the external environment increases and, as a result, the costs of heating the room in winter and cooling in summer are reduced;
• with similar protective qualities, glass with a protective film can be knocked out from the inside of the room.

Requirements for the installation of bulletproof glazing

Protective panels must have a resistance class not lower than the resistance class of the applied protective glazing. For class B1 (P1) panels must be made of sheet steel with a thickness of at least 6 mm. For class B3 (P3) - from armor alloy sheets with a thickness of at least 4.5 ... 7 mm.

Trays for transferring money or documents, openings for negotiations must be of a design that excludes the penetration of a bullet into the protected area when fired from the outside.

The vertical supports must be securely attached to the ceiling and floor. Horizontal structural members should be securely anchored at each joint and, if possible, anchored to walls.

Doors to the protected area must provide the same level of protection as the bulletproof glazing used. In addition, they must open outward and be fitted with a self-locking lock.

Any window in the protected area must be protected by bulletproof glazing of the same class as that installed inside the building.

Test methods for bullet-resistant glass

The essence of this method is to determine the resistance of laminated glass to the effects of certain types of firearms. The tests are carried out on three samples of laminated glass with dimensions of 500 × 500 mm. Draw an equilateral triangle at the center of the test piece with a side length of 120 mm. Three shots are fired at the vertices of this triangle. The glass is considered to have passed the test in the absence of penetration.

Requirements for testing bulletproof glass

• the test piece is installed in a rigid frame with fixtures;
• the rigid frame should not move under the impact of bullets;
• the test piece must be installed perpendicular to the direction of movement of the bullet;
• all four edges of the glass should be evenly clamped, the clamping width should be (30 ± 5) mm, while the target area should be at least 440 x 440 mm;
• the clamping forces should prevent the specimen from dislodging during the test, without stressing the result.

A shard storage box is installed behind the test specimen, which is a chamber that serves to collect glass fragments separated from the rear surface of the test specimen and a bullet that has passed through the test specimen.

The device for measuring the speed of a bullet is an electronic system that measures the time of flight of a bullet between two sensors - targets located at a fixed distance of 300 ... 500 mm along the trajectory of the bullet. When the bullet passes through the first target sensor, a pulse is formed, which turns on the frequency counter, which counts the number of pulses generated by the high-frequency generator of the device. When the bullet of the second target sensor passes, the pulse is stopped. The bullet speed is determined by calculation. The bullet velocity is measured at a distance of not more than 2.5 m in front of the test specimen. The measurement error should not exceed 1.0 m / s.

When a bullet hits an obstacle, the bullet and the protection material itself are damaged: the huge kinetic energy of the bullet's movement is extinguished due to the deformation of the material that is compressed and bursting by it (inelastic deformations). Most bullets (for machine guns or rifles) contain a very strong heavy steel core, after flattening the shell, it penetrates deep into the material.

To ensure the cleanliness of the tests, a sheet of thin metal foil is placed behind the test specimen, the damage of which can be used to determine the test results. The protection class depends not only on the means of destruction, but also on the chosen cartridge and bullet.

Testing bulletproof glass

• weapons and ammunition are selected in accordance with the protection class for which the laminated glass is to be tested;
• before the tests, several preliminary shots are fired to determine whether the actual impact speed corresponds to the permissible one;
• the sample is installed in the frame with the attacked side to the weapon;
• fire three shots at the test piece in accordance with the test conditions. Determine the impact speed and the distance between the centers of the three impacts with an accuracy of 1 mm;
• inspect the test specimen for the presence of through holes;
• check for the presence of glass fragments and fragments separated from the back surface of the test specimen in the shards storage box;
• the nature of the defeat is controlled after each shot according to the state of the control screen and the back of the sample;
• a lumbago is considered to be through penetration of the sample by a bullet or its fragment;
• the glass is considered to have passed the test if there is no penetration of the control screen by a bullet or glass fragments.

Classification of bulletproof glass for resistance to bullets

Glass protection class	Weapon Type	Name and index of the cartridge	Bullet core type	Bullet weight, g	Bullet speed, m / s	Firing distance
В1 - First class of protection	Makarov pistol (PM)	9 mm pistol cartridge 57-N-181 7.62 mm	Steel	5,9	315 ± 10	5
B2 - Second class of protection	Tokarev pistol (TT)	pistol cartridge 57-Н-132С or 57-Н-134С	Steel	5,5	420 ± 10	5
B3 - The third class of protection	AK-74 assault rifle	5.45 mm cartridge with 7N10 bullet	Steel heat-strengthened	3,5	880 ± 10	5-10
В4 - The fourth class of protection	AKM assault rifle	7.62 mm cartridge with a bullet 57-N-231	Steel heat-strengthened	7,9	715 ± 10	5-10
B5 - Fifth class of protection	Sniper rifle (SVD)	7.62 mm cartridge ST-2M	Steel heat-strengthened	9,6	825 ± 10	5-10
B6 - Sixth class of protection	Sniper rifle (SVD)	7.62 mm cartridge BZ-32	Steel	10,4	820 ± 10	5-10

Video about armored glass

The video on bulletproof glass was filmed for the "How It Works" program.

For a long time, armored glass has become an integral part of protecting homes, shop windows, and cars from intruders or armed attack. This structural element is often referred to as transparent armor. Armored glasses are widely used in the life of an ordinary person, and in law enforcement and security structures. Their importance in the modern world cannot be underestimated.

Armored window construction

Armored glass is a translucent product that protects people and material property, valuables from theft, defeat, damage, and also protects from penetration into the room from the outside through the window opening. These products include two elements:

1. Armored glass. It consists of several layers of transparent glass, which are glued together with a polymer material that hardens in the sun. The thicker the product, the higher the level of protection.
2. Frame. It is made of aluminum or steel profiles, very rarely from wood. To give the system protective properties, it is reinforced with heat-strengthened steel plates. Such overlays must reliably overlap the joint between the frame and glass.

The mass of finished armored structures can be more than 350 kg per square meter. This is ten times more than the weight of a conventional glass unit. To compensate for the mass, they are equipped with electric drives.

Types of armored glass

Armored glass is classified according to its ability to withstand a certain type of destructive impact.

According to this criterion, all structures can be classified into several groups:

1. Anti-vandal windows.
2. Break-resistant products.
3. Anti-firearms constructions.

Automotive protective structures are placed in a separate group, since special requirements are imposed on them. armored glasses and requirements for their manufacture are determined by GOST 51136-97 and GOST 51136-2008. Each type of transparent protection is set for protection in a specific environment.

Vandal-proof glass

Vandal-proof windows protect people from shrapnel when intruders try to break it. They represent a multilayer glass unit with an air chamber, where a special one is glued to the glass. Films, in turn, are made of thick plastic. The fragments "stick" to it, so that they do not fly in different directions.

Such structures are used most often in commercial facilities and in the private sector to protect both windows and doors, as well as showcases. According to GOST, they are divided into three classes - from A1 to A3, each of which is distinguished by its resistance to the impact of a certain force.

Burglar-resistant glass

Burglar-resistant armored glass differs from the anti-vandal version only in its resistance to destructive effects. Such a product provides protection against repeated blows with a sledgehammer or hammer, and is able to withstand a car ramming. Most often, such designs are used to protect banking institutions, shops, establishments with a large turnover of funds, as well as shelves for storing narcotic drugs.

According to domestic standards, depending on how many shocks the burglar-resistant glass can withstand, it is assigned a protection class from B1 to B3. The more blows with a blunt or sharp object the structure can withstand, the higher the class.

Bulletproof glass

Bulletproof glass provides protection against through penetration by bullets or their fragments. They are reinforced multilayer structures fastened with a special polymer material. Similar structures are installed at facilities where the risk of an armed attack is high: in the departments of the Ministry of Internal Affairs, at security posts, checkpoints and in other similar places.

Bulletproof glasses are divided into protection classes from B1 to B6a. Structural tests are carried out with various types of firearms - from a Makarov pistol and a Kalashnikov assault rifle to a Dragunov sniper rifle. During the tests, bullets of various weights and with a steel, heat-strengthened or special core are used.

Armored glass for car

The car is equipped with reinforced side rear and windshields. Their main distinguishing feature is their service life. If a standard armored window can last for several decades, then products for a car serve no more than 5-6 years. This is due to the nature of the loads that glass is subjected to on a daily basis.

Such translucent armored elements are a multilayer glass unit, which is additionally reinforced with a shockproof film. Some of them, in addition to protecting against flying debris, protect against ultraviolet radiation. Often the windshields are covered with a thicker film than the side and rear windows.

One day in 1903, the French chemist Edouard Benedict was preparing for another experiment in the laboratory - without looking, he reached out for a clean flask that was on a shelf in a closet and dropped it. Taking a broom and a scoop to remove the fragments, Eduard went to the cabinet and was surprised to find that, although the flask had broken, all its fragments remained in place, they were connected to each other by some kind of film. The chemist called a laboratory assistant - he was obliged to wash glassware after the experiments - and tried to find out what was in the flask. It turned out that this container was used a few days ago during experiments with cellulose nitrate (nitrocellulose) - an alcoholic solution of liquid plastic, a small amount of which, after the evaporation of alcohol, remained on the walls of the flask and solidified into a film. And since the plastic layer was thin and transparent enough, the technician decided that the container was empty.

A couple of weeks after the story with the flask that did not fly to pieces, Eduard Benedict came across a note in the morning newspaper, which described the consequences of head-on collisions of a new form of transport in those years - cars. The windshield shattered into fragments, inflicting multiple cuts on drivers, depriving them of sight and normal appearance. The photographs of the victims made a painful impression on Benedict, and then he remembered the "unbreakable" flask. Throwing himself into a laboratory, the French chemist devoted the next 24 hours of his life to creating safety glass. He applied nitrocellulose to glass, dried the plastic layer, and threw the composite onto the stone floor - over and over and over again. This is how Edward Benedict invented the first triplex glass.

Laminated glass

Glass formed by several layers of silicate or organic glass connected by a special polymer film is called triplex. Polyvinyl butyral (PVB) is commonly used as the polymer bonding glass. There are two main ways of producing laminated triplex glass - jellied and laminated (autoclave or vacuum).

Jellied triplex technology... Sheets are cut to size, if necessary, they are given a curved shape (bending is performed). After thoroughly cleaning the surfaces, the glasses are stacked on top of each other so that a gap (cavity) with a height of no more than 2 mm remains between them - the distance is fixed using a special rubber strip. The combined sheets of glass are set at an angle to the horizontal surface, polyvinyl butyral is poured into the cavity between them, a rubber insert around the perimeter prevents it from flowing out. To achieve uniformity of the polymer layer, the glasses are placed under a press. The final connection of glass sheets due to the curing of polyvinyl butyral takes place under ultraviolet radiation in a special chamber, inside which the temperature is maintained in the range from 25 to 30 o C. After the formation of the laminated glass, the rubber tape is removed from it and the edge is turned.

Autoclave laminated triplex... After cutting, edging and bending glass sheets, they are cleaned of contamination. At the end of the preparation of float glass sheets, a PVB film is placed between them, the formed "sandwich" is placed in a plastic shell - in a vacuum installation, air is completely removed from the package. The final connection of the sandwich layers takes place in an autoclave at a pressure of 12.5 bar and a temperature of 150 ° C.

Triplex vacuum lamination... Compared to autoclave technology, vacuum triplexing is performed at lower pressures and temperatures. The sequence of their working operations is similar: cutting glass, shaping it in a bending furnace, turning edges, thorough cleaning and degreasing of surfaces. When forming a "sandwich", an ethylene vinyl acetate (EVA) or PVB film is placed between the glasses, then they are placed in a vacuum machine, previously placed in a plastic bag. Soldering of glass sheets occurs precisely in this installation: air is evacuated; The "sandwich" is heated to a maximum of 130 ° C, the film is polymerized; the triplex is cooled to 55 o C. Polymerization is carried out in a rarefied atmosphere (- 0.95 bar), when the temperature drops to 55 o C, the pressure in the chamber is equalized to atmospheric, and as soon as the temperature of the laminated glass is 45 o C, the formation of the triplex is completed.

Laminated glass, created by the filler technology, is more durable, but less transparent than laminated triplex.

Car windshields are created from glass sandwiches made according to one of the triplex technologies; they are necessary for glazing high-rise buildings, in the construction of partitions inside offices and residential buildings. Triplex is popular with designers - products made from it are an integral element of the Art Nouveau style.

But, despite the absence of fragments when hitting a multilayer "sandwich" of silicate glass and polymer, it will not stop the bullet. But the triplex glasses considered below will do it quite successfully.

Armored glass - history of creation

In 1928, German chemists create a new material that immediately interested aircraft designers - plexiglass. In 1935, Sergei Ushakov, the head of the Research Institute "Plastics", managed to get a sample of "flexible glass" in Germany, Soviet scientists began researching it and developing a batch production technology. A year later, the production of organic glass from polymethyl methacrylate was started at the K-4 plant in Leningrad. At the same time, experiments were started to create armored glass.

Tempered glass, created in 1929 by the French company SSG, was produced in the USSR in the mid-1930s under the name "Stalinite". The tempering technology consisted in the following - sheets of the most common silicate glass were heated to temperatures in the range from 600 to 720 о С, i.e. above the softening temperature of the glass. Then the sheet of glass was subjected to rapid cooling - flows of cold air in a few minutes lowered its temperature to 350-450 o C. Thanks to tempering, the glass obtained high strength properties: impact resistance increased 5-10 times; bending strength - at least twice; heat resistance - three to four times.

However, despite its high strength, the "Stalinite" was not suitable for bending in order to form the canopy of the aircraft cockpit - the hardening did not allow it to bend. In addition, tempered glass contains a significant number of internal stress zones, a light impact on them led to the complete destruction of the entire sheet. Stalinit cannot be cut, processed or drilled. Then Soviet designers decided to combine plastic plexiglass and "Stalinite", turning their disadvantages into dignity. The preformed lantern of the aircraft was covered with small tempered glass tiles, and the glue was polyvinyl butyral.

The entry of the former Soviet republics into capitalism at the beginning of the 90s sharply increased the demand for protection with armored glass for cars of collectors and currency exchange offices. At the same time, there was a need for "transparent armor" for passenger cars of businessmen. Since the production of real armored glass was expensive, as well as the final product, a number of companies started to produce imitation armored glass - it was a triplex of rather mediocre quality, film PVB polymerization was carried out in an accelerated mode, using ultraviolet irradiation. The finished product was able to withstand a pistol bullet from a distance of 5 meters, i.e. corresponded only to the 2nd class of protection (there are six of them). Massive armored glass of this type did not withstand temperature drops of more than +20 and below -22 o C - after six months, the laminated layers partially exfoliated, their already low transparency was seriously reduced.

Transparent armor

Modern bulletproof glass, also called transparent armor, is a multilayer composite formed by sheets of silicate glass, plexiglass, polyurethane and polycarbonate. Also, the armored triplex may include quartz and ceramic glass, synthetic sapphire.

European manufacturers of bulletproof glasses produce mainly triplex, consisting of several "raw" float glasses and polycarbonate. By the way, non-tempered glass among companies producing transparent armor is called "raw" - it is "raw" glass that is used in triplex with polycarbonate.

A polycarbonate sheet in such a laminated glass is installed on the side facing the inside of the protected area. The task of the plastic is to damp the vibrations caused by the shock wave when the bullet collides with the bulletproof glass in order to avoid the formation of new fragments in the sheets of "raw" glass. If there is no polycarbonate in the triplex, then the shock wave moving in front of the bullet will break the glass even before it actually comes into contact with them and the bullet will pass through such a "sandwich" without hindrance. Disadvantages of bulletproof glasses with a polycarbonate insert (as well as with any polymer in the triplex composition): significant weight of the composite, especially in classes 5-6a (up to 210 kg per m2); low resistance of plastic to abrasive wear; peeling of polycarbonate over time due to temperature extremes.

Quartz glass... It is made from silicon oxide (silica) of natural origin (quartz sand, rock crystal, vein quartz) or artificially synthesized silicon dioxide. It has high heat resistance and light transmission, its strength is higher than that of silicate glass (50 N / mm 2 versus 9.81 H / mm 2).

Ceramic glass... It is made of aluminum oxynitride, developed in the USA for the needs of the army, the patented name is ALON. The density of this transparent material is higher than that of quartz glass (3.69 g / cm 3 versus 2.21 g / cm 3), the strength characteristics are also high (Young's modulus is 334 GPa, the average bending stress limit is 380 MPa, which is practically 7-9 times higher than those of silicon oxide glasses).

Artificial sapphire (leucosapphire)... It is a single crystal of aluminum oxide, in the composition of armored glass gives the triplex the maximum strength properties possible. Some of its characteristics: density - 3.97 g / cm 3; average bending stress limit - 742 MPa; Young's modulus is 344 GPa. The disadvantage of leucosapphire lies in its significant cost due to high production energy costs, the need for complex machining and polishing.

Chemically toughened glass... "Raw" silicate glass is immersed in a bath with an aqueous solution of hydrofluoric (hydrofluoric) acid. After chemical hardening, the glass becomes 3-6 times stronger, its impact strength increases sixfold. The disadvantage is that the strength characteristics of toughened glass are lower than that of thermally toughened glass.

Armored glass frame

The use of armored triplex in the glazing does not mean that the opening blocked by it will be bulletproof - a frame of a special design is needed. It is created mainly from metal profiles, most often aluminum. Steel pads are installed in the grooves located along the junction line of the triplex and the frame profile, protecting the weakest point in the armored window structure from impact or contact with a bullet.

Protective armored strips can also be installed outside the frame structure, however, this will reduce the aesthetic characteristics of the window. To achieve the maximum level of protection, frames can be made entirely of steel profile (in this case cover plates are not needed), but they will become very cumbersome and costly.

The weight of an armored window often exceeds 300 kg per m2; not every building and structural material is able to withstand it. Therefore, the installation of an armored window structure is permissible only for reinforced concrete and brick walls. Due to its high weight, it is not easy to open the sash of an armored window; servos are used for this purpose.