DE2163107A1 - Process for treating transparent panes or foils made of plastic - Google Patents

Description

Vcx-Fahrcn for handling transparent panes or Plastic films.

The invention relates to a method for treating panes or sheets of transparent plastic, in particular at elevated temperature and pressure, the so licrgcs'fcellen foils or panes can be used as windows in Aircraft or as components of laminated glass for burglar-proof shop windows and the like.

Attempts have already been made in the case of extruded transparent plastic panes, such as polycarbonate panes, those caused by unevenness and unevenness of the surfaces also reduce the optical distortion caused. This is done by polishing under pressure and conditionally high temperatures, and high pressures. So far one has been content with improving the visually poor surface without doing the Change the shape of the disc. If you had tried so far, nine plastic discs polished under pressure in changing its shape, the pane broke.

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The previous processes remained panes made of polycarbonates, which improve their optical properties the surfaces were polished under pressure, flat when originally flat and curved when originally were bent. It was not previously possible that

Shape of curved discs treated at high temperatures to change, since the thermal warping could not be regulated to such an extent that mass production was possible.

The invention allows the shape of a disc to be changed simultaneously with the polishing of the surfaces under pressure. This creates transparent panes that can be used as window panes or as components of window panes made of laminated glass. The panes according to the invention have improved optical properties and at the same time the desired shape. The method of the invention can be regulated to such an extent that ρ is always the same, even with mass production. The method according to the invention can be used particularly well with panes made of polycarbonates and with stretched panes made of polyacrylic composites. One can

the inventive method but also with foils' or Use discs made of other materials if they can be brought into the desired shape at the working temperatures and pressures, and if the optical properties of the surfaces are improved at the same time.

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According to the invention, the panes or foils are between rigid press plates initially heated to the working temperature at a relatively low pressure. Then the The pressure is increased and preferably kept at the working temperature for so long that the desired results are achieved. This new succession of heating and application of Pressure results in a simultaneous shaping and polishing under pressure of the disks or foils made of plastics, without break them here.

Another embodiment of the invention makes it possible relatively thin disks or sheets of polycarbonates during the simultaneous molding and polishing under Pressure to weld together, using relatively thick even clear slices of plastic with the desired optical properties. This The latter method is particularly suitable for treating panes or films made of polycarbonates, in particular of the type of bisphenol compounds.

Used in accordance with a further embodiment of the invention a suitable release agent, which is neither on the pane or film nor on the pressing surface of the press plates adheres. It is also possible to carry out the procedure in an evacuated, tightly closed bag »That leaves the use of higher temperatures than was previously permitted

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in the treatment of polycarbonates without this to impair the optical properties of the panes or films made of the polycarbonates. You can therefore use discs

Poly
or treat foils made of / carbonates at temperatures

which the panes or foils are welded together relatively thick, uniform slices of the desired shape with smoother surfaces "than was previously possible.

The British patent Wr. 1 I63 5 ^ 6 describes a procedure for stretching and polishing objects made of polyacrylic compounds. Here, a cast molded body made of polyacrylic compounds is heated to its softening temperature, and pressed together between two curved or flat polishing plates covered with a thin film of lubricant are coated. Printing continues until the desired thickness is achieved.

Canadian Patent No. 857,759 describes a method for polishing under pressure of windows or foils axis polycarbonates. An overpressure of ecwa 7 to about 20 kg / cm and the temperature is kept at about 120 to 150 C so long that the polycarbonate is cold flows. The optical distortion caused by surface irregularities is thereby eliminated or

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decreased olmo to change the shape of the disk. The working temperature is SG to LOG C below the melting range from 25 to 225 C, that for bisphunol-A-Polyccirbonate according to the book "Polycarbonate" by WF, Christpher and DW Fox, published by the publishers Roinhold & Co., New York, I.962, page 24, applies.

The invention relates to a method of treating a Disc or film made of a transparent plastic with an optically poor surface and a shape that is different from of the desired shape is different. The process consists in that the disc or film is placed under pressure between brings two opposing smooth complementary surfaces of two rigid Preßplfitten whose surfaces correspond to the desired final shape. Then it is heated to a temperature at which using a relatively low pressure the desired shape is achieved. It is then kept within this temperature range and increases the pressing pressure so far that the disc or film is deformed in the desired 'way, at the same time the optical distortion caused by surface irregularities is eliminated or reduced. Then cool down and reduce the pressure.

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The disc or film and the rigid press plates can be enclosed by a thin elastic bag made of a substance impermeable to liquids. The bag is evacuated and tightly closed before the heat and pressure treatment described is carried out. Preferably, the sheet or film made of the transparent plastic is brought into a shape that is approximately the desired before the treatment according to the invention. End shape corresponds. You can use a release agent that does not adhere to the pane or film and not to the press plates under the working conditions. This enables the use of higher temperatures.

With the invention it is possible to produce panes from polycarbonates, the thickness of which is greater than the thickness which is achieved by extrusion according to the known processes. For this purpose, two or more panes or foils made of the transparent plastic, for example made of polycarbonate, are used, with their surfaces lying on top of one another between the surfaces of the press plates. Here, too , a separating material can be used between the plastic and the press plates. The whole is then treated according to the invention at higher temperature and pressure , if appropriate within a plastic bag. Here, too, the use of a separating substance enables higher temperatures to be used.

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Transparent panes or foils made of polycarbonates, e.g. made of Disphenoi-A polycarbonate polyesters are in the US patents No. 3 028 365 and JMi-. 3 II7 019 describes «. The US patent Wr. 3,215,668 described mixed Carbonate-carbate polyesters have properties thanks to which these substances can be used as a substitute for conventional transparent panes, e.g. made of silicate glass0 For example, these panes have a lower specific weight than glass, are tougher than this and have a higher impact resistance than glass panes of similar thickness, the substances mentioned are also tougher and have a higher Impact resistance than other clear plastics «The The toughness and impact resistance of the polycarbonates are based on their high ductility and on the plastic deformability, whereby, under high tension, the polycarbonates deform rather than break and crack. These The latter property can be determined with brittle substances, like silica glass and rigid plastics.

Because of these properties are transparent panes Made of polycarbonates viewed as particularly suitable to stand alone or together with other very impact-resistant materials Bulletproof components and panes in schools, banks, sports arenas and the like to be used. Despite the high impact resistance of the polycarbonates, transparent panels were

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bon from these substances usually not usable · because. they distorted optically exceptionally strong.

Transparent polycarbonate panes of the desired thickness in order to obtain high impact resistance for panes, ie with a Dickon between about 1 and 10 ram, are produced by hot extrusion. The distortion bands on ψ the extruded disks are likely due to the contact between the surfaces of the extrudate and the extrusion nozzle when the disks are formed. Although the extruded disks are transparent and have sufficient optical clarity, they are nevertheless not usable because they distort. The distortion bands are similar to those that appear as a pattern on very poor sheet glass. Usually they are based on the fact that the surface is not smooth enough.

The following procedure is used to test the distortion bands on panes of glass. A box with an opening of k 5 cm, which contains a bulb of 1000 watts, is used as the light source. The light source is held 8 inches away from a screen. Preferably, a screen 8θ 100 cm, made of pressed cardboard with a smooth surface, which is sprayed with a white latex paint. The screen is in ύοτ Hegel on a vertical wall with the help of an adhesive odor on the channel

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clay attached to nail odor screw heads in don areas to avoid where the venicrntiigf-mustcr be observed target.

During the test, the pane of glass to be tested is placed between the light source and the screen at such a distance brought from the screen that on this the complete distortion pattern you can see. Then the glass pane is inclined at such an angle that the distortion bands at can best be seen as clear hello or dark areas on the screen. The disc will then return to one position brought parallel to the surface of the screen and slowly brought against the screen while gently moving up and down » When approaching the screen are the stronger ones first Seeing distortion bands until they disappear. At the beginning of the disappearance of the strongest distortion bands

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ends / the movement of the disc and measures the distance between it and the screen. This distance is a measure of the optical distortion. Discs with a measured greater distance from the screen are preferable to those at which a short distance to disappearance the distortion bands can be measured.

Panes of glass with a thickness of 2.4 to 6.1 mm, at do «. If the measured distance to the screen is less than 16 to 20 cm, panes of the

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of the same kind with a measured distance between disc and screen of 35 to 38 a are considered good or excellent. In the intermediate area, too, glasses with a greater measured distance between the screen and the pane are to be preferred to those with a smaller ».

Extruded transparent panes of bisphenol A polycarbonates with a thickness of 3 »2 mm have such an optical distortion that the distortion bands only disappear at a distance of 7.5 to 12.5 cm between the screen and the pane. Such disks can be considered bad. The unwanted optical distortion of the extruded material is likely due to surface irregularities that arise during extrusion. It is clear that these undesirable properties are improved extruded transparent slices of polycarbonates Ψ need to make for transparent slices useful au.

Similar undesirable optical distortions can also be observed for transparent panes made of methyl methacrylates, Cellulose acetates and vinyl compounds. By hot polishing under pressure, the optical distortion in the case of transparent panes made of these materials can be reduced somewhat. This is done by reaming under pressure between press plates at a temperature equal to or higher than

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the melting range or softening range of the substances. at At these elevated temperatures the fabrics flow easily and surface irregularities appear when touched reduced with the smooth press plates.

Polycarbonates resemble thermoplastics in certain respects Fabrics that are polished under pressure in a known manner are. But they have other properties through which the known method of polishing under pressure at temperatures near or above the melting point does not is more feasible.

In the aforementioned book by Christopher and Fox, Bisphe-r nol-A polycarbonates have a melting range between 21.5 and 225 ° C specified. As a rule, the melting range of polycarbonates is between about 200 and about 230 C.

A 3i2 mm thick disk made of bisphenol-A polycarbonate, which was kept in a room at 23 ° C. and a relative humidity of 18 % , was pressed between pressing plates at a temperature of 195 ° C. for 5 minutes. The surface of the polycarbonate pane had become dark so that it could not be used for transparent glazing.

Other polycarbonate panes, which had initially been ^{dried for 1.5 to 1} hour at 1.50 ° C., were pressed between

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panels pressed at 200 to 230 ° C. The surfaces were not darkened. Against it was bycli. Polishing while pressing in the Viärine reduces the impact resistance. Other disks polished in the heat under pressure were so stressed that they broke. * They broke in the same way as other brittle materials, and no plastic requirement was found, as was the case with tough, ductile and not Polished extruded panes made of polycarbonates, so it can be seen that the polishing under pressure at elevated temperatures, which come close to the melting range of the Polycax * bonate, reduces the optical distortion just as with other thermoplastic materials, but that the transparency and the impact resistance are adversely affected When the polycarbonates are pre-dried under pressure before hot polishing, the optical clarity can be retained, but the high impact resistance disappears.

It is not yet entirely clear why the material was used changes from a ductile to a brittle state. Bisphenol A polycarbonates are said to have a glass transition temperature of about 150 C. They are very resistant to degradation by oxidation at temperatures up to about 150 C. Any

can
or both of these properties / can be restored when the molded disc is reheated to a temperature above 150 ° C. It is said that polycarbonates come into contact

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are not easily degraded with air when heated above the transition temperature. The simultaneous application of increased pressure only increases the possibility of a reduction. The presence \ ^r on moisture xuid perhaps of other impurities affects this substance even when heated to temperatures above about I50 C.

The polycarbonate disks are preferably made by reacting di (monohydroxyaryl) alkanes with Derivatives of carbonic acid such as phosgene and bischloro carbonic acid esters of di (monohydroxyaryl) alkanes.

The aryl radicals of the di (monohydroxyaryl) alkanes can be the same or be different. The aryl radicals can also contain substituents which are formed in the conversion to polycarbonates do not react, such as halogen atony or Alley 1 residues, e.g. Methyl, ethyl, propyl, tertiary butyl radicals. The alkyl residue the di (monohydroxyaryl) alkanes, which form the two benzene rings connects, can be an open chain or a cycloaliphatic ring and, if desired, can be replaced by a Be substituted aryl rust.

Suitable di (monohydroxyaryl) alkanes are, for example, ¹ I , h '-dihydroxy-diphenyl-methane, 2, 2- (' l, 't' -dihydroxy-diphenyl) -propane, 1 , 1- ( ¹ I ₁ ¹ I ¹ -DihyiJi-oxy-diplicnyl) ~ cyclohexane, 1, 1 ~ ((t, 4 · - Di.J) ydroxy-3, 3 '-Dime thy! »Diphenyl) -cyclohoxane, 1, l- ( 2.2 ^e -

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Dihydroxy-4,4 '-Dimethyl-Diphcuiyl) -Ikit> m, with a boiling point of 185 to 188 ° C under a pressure of 0.5 minlg), 2.2 (2,2'- · Dihydroxy-4 Jk ' -Di-tert-butyl.-diphenyl) propane or 1, 1 '- (4, 4' dihydroxy-diphenyl) -1-phenyl. -Ath on; also methane derivatives which contain two hydroxyaryl radicals (i \ n & n alkyl radical with at least two carbon atoms and a second alkyl radical with one or more carbon atoms, such as 2,2- (4,4'-dihydroxy-diphenyl) -butane, 2,2- ( 4,4'-dihydroxy-diphenyl) pentanes (with a melting point of 1A9 to 150 ° C.), 3,3- (4,4'-dihydroxy-diphenyl) pentanes, 2, 2- ( k , ^ i 'dihydroxy -Dipiienyl) llexane, 3, 3 '(4, k ' dihydroxy-diphenyl) llexane, 2,2- (4,4'-dihydroxy-diphenyl) -4-methyl-pentane (with a melting point of 15-152 ° C ), 2, 2- (4,4'-Dihydroxy-Diphenyl) -Heptane (with a boiling point of 198 to 200 ° C at 0.33 niniHg), 4, 4- (4, 4 '-Dihydroxy-Diphenyl) - Heptane (with a melting point of 148 to 149 C) or 2,2- (4,4 * -dihydroxy-diphenyl) -tridecane. Suitable Dl- (monohydroxyaryl) alkanes are those whose two aryl radicals are different, for example 2, 2 - (4,4 ^1- Dihydroxy-3'-methyl-diphenyl) propane and 2, 2- (4, 4'-dihydroxy-3-methyl-3'-isopropyl-diphenyl) butane. Suitable di- (monohydrox yaryl) alkanes whose aryl radicals contain halogen atoms are, for example, 2, 2- (3, 5, 3 ', 5'-tetrachloro-4,4'-dihydroxy-diphenyl) propane, 2,2- (3, 5 \ 3 '>5'-Totrabrom-4,4'-dihydroxy-diphenyl) -propane, (3,3 '-Dj chloro-4,4'-dihydroxy-diphenyl) -methane and 2,2' -dihydroxy -5, 5'-difluoro-dijjlienyl-methane. Suitable di (monohydroxyaryl) alkanes in which the

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1 ^

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The alkyl radical connecting both IJeiizolring-e is substituted by an arylcyte are, for example, ( h , k '-dihydroxy-diphenyl) -pheny-1-methane and 1, 1- ( h- , 4-dihydroxy-oxy-dijibenyl) 1 -Phony1-Xthan.

In order to achieve special properties, the mixtures has been used by various Ui- (monohydroxyaryl) alkanes » wherein mixed polycarbonates disfigure.

The conversion of the di- (monohydroxyaryl) alkanes mentioned to high molecular weight polycarbonates by reaction with the mentioned derivatives of carbonic acid can be carried out in a known manner. For example, the di (monohydroxyaryl) alkanes can be reesterified with diesters of carbonic acid, such as dimethyl, diethyl, dipropyl, dibutyl, diamyl, dioctyl, dicyclohexyl, diphenyl, di-o, p-tolyl, for example -Carbonates at elevated temperatures between about ^ O and about 320 C, in particular between about 120 and about 280 C.

The polycarbonates can also be prepared in such a way that phosgene in solutions of di- (monohydroxyaryl) -alkanes in organic bases such as dimethylaniline, diethylaniline, trimethyl-, amine and pyridine, or in solutions of di- (Monoliydr oxy aryl) -alkanone in inert organic solvents such as gasoline, ligroin, cyclohexane, methylcyclohexane, benzene, toluene, Xy3.ol,

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Chloroform, Methy leiiclil oriel, Kohlcnstofflol raclilorid, Tri -

vtiiä chlorethylene, diclilorethane, Metiiylacctnt / Athylacetrt, introduces, with the addition of an acidic substance mentioned above.

A particularly suitable process for the production of carbonates is that phosgene is mixed with a white solution or suspension of Alkalimeta.1! salts, ide beispiclsvreiso the lithium, sodium, potassium or calcium salts of di (monohydroxyaryl) alkalis introduces, preferably in the presence of an excess of a base such as the Ilydroxyde or carbonates of lithium, sodium, potassium or calcium. Axxs the watery The polycarbonates are the solution.

The reaction in the aqueous solution is accelerated by the addition of inert solvents of the above-mentioned Ai't in which the phosgene and possibly those produced Polycarbonates are soluble.

The phosgene can be used in equivalent amounts, but preferably in an excess.

Finally, one can also use the di- (monohydroxyaryl) -AClkane approximately equimolar amounts of the dischlorocarbonic acid esters of React di (monohyclroxyaryl) alkali under appropriate conditions.

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In the · production of polycarbonates according to the various If it is advantageous to use coagulated sets of Reduk i; i. oiibmltteln to be used with spJ o.lsv / eisc sodium or • potassium sulfide or sulfite and dithionite or free phenol and

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ρ -Ter t - Bat y lphen ol.

When adding; Non-functional compounds which react with phosgene or with the end groups of the polycarbonates, which are the radicals of the chlorolylenic acid esters and terminate the chains, it is possible to regulate the molecular weight of the polycarbonates within wide limits. Such additives include phenols, such as phenol , Tert-butyl-phenol, cyclophenylhexol, 2,2 (4-II-hydroxyphenol- (t'-methoxyphnnyl) -propane, aniline and methylaniline

The reaction of the di (monohydroxyaryl) alkanes with phosgene or the carbonic acid esters of the di (monohydroxyaryl) alkanes can be carried out at room temperature or at lower and higher temperatures, ie between the freezing point and the boiling point of the mixture. Reference is made to the US-Peitentßchrift no. 3,028,365, column 1, line 21 to column 3, line 1, _o referred The consider hon of the polycarbonates preferably have a thickness between about 1.5 and about 10 mm, in particular between about 2.5 and 6.5 mriE »in some cases it is appropriate to use copolymers of different dihydroxy-aryl-propanes in order to achieve special qualities.

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Other transparent materials are in the US ^I} atfmtschrift no. 3 "069.301, column 1, lines 62-68 describes the rigid sense, scratch-resistant and are virtually non-hygroscopic.

Acrylic resins, especially polymethacrylates, are popular because of their very good optical properties, such as clarity and transparency, Processed to a large extent into cladding and windows in Flugzeixgen. Two polymethacrylates suitable for this are sold by Rohm & Heins under the names "Plexiglas II" and "Plexiglas 55" »Both resins consist essentially of polymethylniethacrylate. you will be both traded and differentiated in the form of cast disks mainly by their heat resistance, whereby "Plexiglas .55" is the more heat resistant.

The cast acrylic resin panes can be used for aircraft windows. However, their impact strength and their resistance to ψ Rißbi.ldung, as well as the shock resistance can be greatly improved dxirch stretching the cast wheels. It can be assumed that this stretching changes the molecular structure of the polymers. The linear molecules are likely to be disentangled and at least partially oriented parallel to the direction of stretching. This increases the impact resistance, the resistance to cracking and the resistance to shock

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improved without sacrificing the excellent optical properties To suffer.

An optimal improvement in the physical properties of disks on the polyacrylate is achieved if such disks are stretched by about 75 to 100% either in the direction of two or more axes. By stretching, the resistance to cracking is increased many times over. This property is a measure of the toughness or shock resistance of the material and is particularly important when glazing aircraft that are under pressure in flight.

A common measure of the resistance to pitting of stretched acrylic resins is the value dW / dA. It expresses the force per unit of the area in which the cracks extend,

when off

rapid growth of cracks /. A cast disk axis of a polyacrylic compound has a value for dW / dA of about 4. After stretching by 75 to 100 % , this value rises to 20 to 30. As this resistance to cracking, the stretched acrylic compounds have excellent resistance to blowing out "if they are damaged during a flight under pressure. The stretched panes made of acrylic compounds have therefore to a large extent replaced the cast and untreated panes in aircraft.

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For certain purposes it is desirable to use the elongated disks made of polyacrylic compounds in layers with another stretched one Disc made of a polyacrylic compound, with a cast Disc made of a polyacrylic compound, with a disc made of a different plastic or with a pane of silica glass to connect in order to produce discs for aircraft.

For example, the stretched disk can be made from a poly-

· Electrically conductive
Acrylic compound layer by layer with a / film or a wire mesh for de-icing or: * defog connect that part
Form the pane or the window of the aircraft. If a transparent, electrically conductive film is used, the coating serves to protect this very sensitive film against damage from scratches and against attack by moisture
or by corrosive gases in the Attno: sphere. The coating also forms an insulation for the film and prevents it
a random basic connection. If one tin deicing or unloading ψ vorwendet fog a conductive wire mesh, this can .His embedded in conventional manner in an intermediate layer between the stretched sheet of the polyacrylic and another sheet of plastic or glass.

A typical ancestor and apparatus for stretching
Polyacrylic compound disks are written in U.S. Patent Reissue No. 2-1978.

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Any material can be used as a separating material at the working temperature and pressure, not on the Sehej be from the plastic adheres. With success you can boispio.lswei.se a thin sheet of cellophane with a thickness of about 0.025 now use. Other suitable substances are, for example, wax-like Emulsions sold under the name “Aircraft Surface Protector” by Lloskins, Geneva, Illinois will.

Other suitable substances are mineral oils, castor oil, fats, thin films of polyethylene terephthaleite, which go under the Ilandel name Mylar are sold, films made of polyethylene and polypropylene, silicone waxes and Te trafluoräthylen-Üborzüge, the be sold under the name Teflon.

The bag according to the invention, within which the method can be performed is preferably as described in in U.S. Patent No. 3,311,517. The bag preferably consists essentially of an outer, oil and moisture-resistant plastic layer, preferably from condensation products of ethylene glycol and terephthalic acid, and from nylon which is impermeable to oil. The inner one Layer ordered from a plastic that can be welded in the warmth, such as polyethylene with a specific gravity between

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about 0.916 and 0.93. The inner layer is outstanding after vaccination Before jumps or increases of about 0.05 min »advance

of soft preferably it consists of plates / ingestreckteni polyethylene glycol torephthalate. The total thickness of the layers should not be greater than 0.125 µm.

The pressing plates for the simultaneous shaping, polishing and welding of the panes or foils made of polycarbonates or polyacrylates preferably consist of chemically tempered glass panes with a minimum thickness of 3 mm. These plates are brought into the desired shape by heating the glass panes to the deformation temperature and then bending them under pressure between two press plates of a mold. Such is, for example, in US Pat ^{. No. 3,367,76;} l described. Then the molded glass sheets are cooled. They are then chemically tempered. For this purpose, an alkali silicate glass or a borosilicate glass, which can easily be chemically tempered, is preferably used.

The impact strength, the breaking stress, the resistance to penetration and the like are used in glass articles, in particular in pressed plates made of soda-lime-silica glass according to the invention, increased if the glass objects are treated with a potassium salt at an elevated temperature, preferably at about ^ 70 C, brings into contact for a short time. The treatment

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times at temperatures above 4.70 C rarely exceed 25 to ¹ k0 minutes, at lower temperatures they are longer. Typical methods of hemi seeing Te nip or η are described in US Pat. No. 3,396,075.

If the glass contains essential amounts of lithium, you can use a sodium salt or use a mixture of a sodium and potassium salt for tempering, or use the two salts one after the other, first the molten sodium salt and then the potassium salt. An alkali metal ion of a larger diameter is likely to be counteracted during annealing on the surface of the glass object an ion of a smaller diameter exchanged. This ion exchange causes a compressive stress on the surface of the glass object, which increases its strength.

'Tempering solidified glass can also be strengthened by thermal /. Here is the glass pane is heated above its stress point to a temperature in the vicinity of the softening point, and then suddenly and quickly quenched below the clamping point. This creates a surface zone under compressive stress above the main mass, which is under tension.

It is also possible to strengthen glass by first tempering it thermally and then chemically, which is thermally tempered glass once or several times at elevated temperatures

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for thermal annealing

doors that are below the Tempertemporaturon / is immersed in molten alkali metal salts. But if the form If the press platform is fixed, it is preferable to use the Proßpifatten to solidify by chemical tempering and ion exchange, because here a temperature is used which is below the deformation s temp ei "a door of the glass lies.

The use of press plates made from chemically strengthened track with complementary shapes that match the shape of the object to be pressed made of plastic is another invention. It is only mentioned here in order to fully describe a preferred embodiment of the invention according to the method.

The invention also relates to the manufacture of clear, molded, smooth sheets of polyacrylic compounds or polycarbonates that are curved and flat, or of curved sheets of polycarbonates that are thicker than those previously available. The invention is particularly important when a transparent pane made of a polycarbonate or a polyacrylate is to be connected in layers with one or more transparent panes made of a silicate glass or a substitute therefor, for example made of a polycarbonate or a polyacrylate. Preferably, one uses an alkali-liierzu Jvieselsäuro glass or a _{glass-Dorsilikat%} that easily

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can be chemically tempered, as well as in that described Type the press plates.

In the case of windows made of layered glass, the individual layers made of glass or the substitute gates are connected to one another through typical interim shifts, e.g. from the ones below named polyurethanes or other known mixtures of substances, such as plasticized polyvinyl acetate, e.g. Butyral.

Polyvinyl butyral is made by reacting butyraldehyde with polyvinyl alcohol. The unreacted alcohol residues are calculated as the percent of the vinyl alcohols remaining in the polymer. Nowadays, laminated safety glass is produced using an intermediate layer that contains a resin, the components of which are polyvinyl alcohol partially condensed with butyraldehyde, so that it does not rccigiert.e Ilydroxylgrupxjen, based on the weight of the vinyl alcohol, less % based Estergruppen - than 3 wt.

as viiiylbutyral to the weight of the vinyl acetate and the remainder acetal groups / contains. This substance is usually referred to as "polyvinyl butyral", more precisely as "partial polyvinyl butyral". This in Polyvinyl butyral used for laminated glasses usually contains a plasticizer.

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Usually these plasticizers are water-insoluble esters of a polybasic acid or a polyhydric alcohol. Triethylene glycol di (2-ethylbutyrate) are particularly good plasticizers for the use according to the invention. Dibutyl sebacate, di (deta-butoxy-ethyl) adipate, and dioctyl phthalate. Other suitable plasticizers include triethylene glycol, which is fully esterified with a mixture of 80 to 90 % caprylic acid and 10 to 20 % caproic acid (US Pat. No. 2,372,522), dimethyl phthalate, dibutyl phthalate, di (butoxy acetyl) sebacate, methyl palmitate , Motlioxymethyl palmitate, triethylene glycol diacetate, tricresyl phosphate, triethyl citate, butylbutyi * yl lactate, ethyl p-toluene sulfonamide, dibutyl sulfone,. Lauryl alcohol, oli! Other plasticizers can of course also be used. Preferred intermediate layers consist of a self-healing transparent resin, such as polyurethanes, preferably those polyurethane mixtures which are formed when an organic polyisocyanate is reacted with a compound which contains several active substances, for example with a polyether-polyol and / or polyester-polyol or a polyaniine. Suitable polyether polyols are described in US Pat. No. Wr. 3,509,015. Such polyurethanes have already been used as intermediate layers in laminated glasses.

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Other polyurethanes that can be used according to the invention include Hydroxyl-terminated polyesters, see US Pat U.S. Patent No. 2,871,210. More suitable Polyurctalmliarzc are in the book '! Polyurethanes Chemistry and Technology "by J. 11. Satinders and K.C. Frisch, Interscience Publishers (1964).

The intermediate layer of polyurethanes is preferably on Place between the surface of a pane made of a polycarbonate or a polyacrylate and the surface of a other sheet made of transparent material such as glass, polycarbonate or polyacrylate, cast and then cured. The preferred polyurethanes include a reaction product of a Polytetramethylene oxide glycols having an average molecular weight of about 550 to about 1,800, one diisocyanate and one Curing agent containing at least 3 hydroxyl groups and 1 Contains diol.

Preferred mixture is .so produced that one first Isocyanate-terminated prepolymer by reaction a diisocyanate and a polytetramethylene oxide glycol. This prepolymer forms one component of a two-component system. The hardener forms the second component with the polyol and the diol. Polytetramethylene oxide glycol resins, whose molecular weight does not fall within the above

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richly fills, have a good, optical vision and good adhesion to the polycarbonate, they can be used for Safety washers cannot be used, as in the case of deep or high temperatures their impact resistance is low. When that Polytetramethylene oxide glycol has a molecular weight below 550 If the resin becomes too brittle at low temperatures, the polytetramethylene oxide glycol has a molecular weight above l800, the mixture is not sufficient at high temperatures rigid, and a sufficient impact resistance does not become achieved.

Polytetramethylene oxide glycols are obtained commercially in the form of a prepolymer which is a reaction product of the above Glycols with diisocyanate. The "Adiprene", the polytetramethylene glycol-toluene diisocyanate prepolymers can be used with good success as self-healing protective covers will. The good properties that make these resins particularly beneficial as a protective layer for a surface can be used from a polycarbonate ensure that the straight-chain polytetramethylene oxide glycols a Have molecular weight within the specified range. The most important factor for good pouring and curing of a surface or a disk is the critical molecular weight of the polytotramethylene oxide glycol,

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Various polyurethanes are made on the basis of polyesters from Mobay Chemical under various names such as "Moiidur" and "I'Jultra than" driven forward. The exact chemical composition these substances are not known, but they probably contain esters of dicarboxylic acids with 2 to 10 Carbon atoms per carboxylic acid group, such as adipic acid, sebacic acid, Acelic acid and succinic acid, which are reacted with a diol with 2 to 10 carbon atoms, such as ethylene glycol, 1, l ~ dutanediol, 1,5-pentanediol, etc., with such an excess of diol that excess alcoholic hydroxyl groups are present via the carbonyl group, and that the resulting polyester has terminal alcoholic hydroxyl groups.

In preparing the prepolymer, the use of toluene diisocyanate is preferred because of its low cost. However, it is also possible to use other organic diisocyanates, such as aromatic, aliphatic and cycloaliphatic diisocyanates and combinations thereof. Such compounds, for example, m-Phenyleii-diisocyanate, 4-chloro-1, 3-l ^J include henylen diisocyanate, k, 4'-diphenylene diisocyanate, 1,5-naphthylene diisocyanate, 1, ^ - tetramethylene diisocyanate, 1,6-IIexainethylene diisocyanate, 1, 10-decarnethylene diisocyanate, 1, 1-cyclohexyl diisocyanate, ¹ I ₁ ¹ I ¹ -ethylene dis- (cyclohexyl isocyanate) and 1, 5-tetrahydronaphthylene diisocyanate. Arylon diisocyanates in which each of the two isocyanate groups is directly linked to an aromatic ring

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connected are preferred. Steriach handicapped types like 3, fj-diethyl-methylene-B.i s (Ί-phenylene-isocyanate) and ο, ο '~ D.i ethyl-p-denzene diisocyanate, in which the two isocyanate groups are different in terms of their reactivity may also be of interest. The diisocyanates can also be substituted by substituents that do not react with the isocyanate groups. In the case of aromatic compounds, the isocyanate groups can be located on the same or on different rings also diners of the monomers diisocyanates and di- (isocyanatoaryl) ureas, such as di- (3-isocycmato- / ± -Methyl-Pbanyl) -IIurea use.

The hardeners for the polyurethane resins contain a polyol that has a crosslinking effect. You can also use a diol if desired that acts as a chain extender.

Various diols can be used as such chain extenders are, for example, glycols, of low molecular weight such as ethylene, propylene, butylene, pentylene, and higher or substituted alkylene diols, as well as various by Hydroxyl-substituted aryl compounds «Particularly good 1, 'i-butanediol, 2, 2-bis- ((i-hydroxy-cyclohexane) propane, 1,5-pentanediol, and 2-methyl-2-n-propyl-1,3-propynediol.

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Road network acting as-er polyols contain vorzugsh ^r else three or more labile hydrogen atoms in the molecule .. They must be further compatible with the reaction system, ie they must be in the reaction mixture is soluble. Theoretically there is a limit to the number of * dec * hydroxyl groups in the molecule. In practice, however, the molecular size affects other properties such as solubility and the like, so that compounds with an excessively high molecular weight cannot be used.

Polyolo with up to 8 or up to 10 hydroxyl groups in the molecule are effective. These common polyols include trimethylol propane, trimethylol heptane, trimethylol ethane, sorbitol, castor oil, the reaction products of allyl alcohol with styrene and the reaction products of various polyols with alkylene oxides «

To achieve the best results, the hardener is used in quantities such that the total of the labile hydrogen

nearly
atoms / stoichiometrically equal is the sum of the free isocyanate groups in the erepolymer. However, useful results can also be achieved if these amounts differ by 5%> preferably only 3 % from the stoichiometric. In order to achieve the best results with different molecular weights within the range mentioned above, certain proportions of diol and polyol must be used. One can for example

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about 3i5 equivalents of a diol to one equivalent of dos Use polyols if the molecular weights are perforated, i.e. a \. * I - see I25O and I800 lying. About 6 equivalents are used of the diol to 1 equivalent of the polyol,. when the molecular weights have an average value of about 650 to 850. Approximately 9 equivalents of the diol become 1 equivalent of the polyol used when the molecular weights are low and χτι one Range between about 550 and 65Ο. · One can be useful Produce resinous intermediate layers with proportions of Diols to the polyol, which are between 1.5s1 and 10: 1.

If you use poly-totramethylene oxide glycols with molecular weights working on the limits of this range, it is possible to change the physical properties to a certain extent by using a diol which acts as a plasticizer in the final product, or a diol which gives the end product a stiffness. In the former case you can, for example, straight-chain poly-butyl-GlycoJe use, in the latter case 2,2-bis (d-hydroxy-cyclohexnn) -Prοχ} on use.

The intermediate layer can simply be produced in such a way that the prepolymer is heated to about 100 ° C. and it is 1 to 2 hours hold under a vacuum for a long time. Then the prepolymer is mixed with the hardener from the polyol and the diol in a suitable one

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Vessel. The mixture is maintained untei · vacuum at a temperature between about 65 and about $ h C to existing or entrapped during the mixing gases zn remove and. to attract viscous liquid. Additional heating, for example, 6 hours heating at I ¹ IO C may be followed by extrusion the CFER.

ICs are made from polymerized films or disks, with all of them

for a glass plastic laminate
for an intermediate layer / required properties, in addition to the ability to adhere to rigid materials such as glass and polycarbonates. The additional listening can be accelerated if it is performed at higher temperatures. It can be finished at lower temperatures if you cure longer. Completely dead panes or foils do not absorb moisture, but have poor adhesion after complete curing.

The invention relates to equilateral molding and polishing under pressure from transparent panes or plastic films, to. made of polycarbonates or expanded polyacrylic compounds. It also relates to the simultaneous molding, polishing under pressure and joining by welding of panes or foils made of transparent plastics, such as polycarbonates, and the simultaneous polishing under pressure and joining by welding together transparent panes or foils made of plastic, such as polycarbonates.

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You can do this by welding together at an elevated temperature and under pressure without the use of adhesives discs, or foils made of the same or different materials connect with each other. You can also apply a thin layer of the

join a material and the action of heat and pressure to another layer without using an adhesive.

The examples illustrate some preferred embodiments of the invention. In all of these examples, the test method for determining optical distortion bands described above was used. For windows in automobiles, a measured distance of 75 ^cm between the window and the screen is acceptable. When curved panes were tested, the curvature was facing the screen.

Example I

A flat, more than lüijcin long and more than 100 cm wide, 6.3 "" η thick slice of bisphenol-A-polycarbonate, which was intended for the production of a window in an aircraft Lockheed 1011, "was made between two smooth discs Brought chemically strengthened glass, which gave the desired cylindrical shape. The pane made of dome polycarbonate and the two glass panes were placed in a flexible bag of li> 5 × 132 cm made of a bag that was resistant to oil and moisture

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Brought material such as that in US Pat. No. * 3 »311 j 517 is described.

The bag was evacuated, sealed and placed in an autoclave with an initial temperature of 30.degree. The temperature in the autoclave was increased in stages to 35 ° C. over 25 minutes, the overpressure in the autoclave being kept at about 1.75 kg / cm. Then, keeping the temperature in the autoclave at I50 C and increased pressure on l4 Irg / ciu 'and the whole held at this Tenrperatur and pressure Curr end k 5 Minu t s.

The mixture was then cooled to about 38 ° C. and the pressure was set to atmospheric pressure and removed the bag and its contents from the autoclave. The shape of the polycarbonate disc corresponded exactly to the surfaces of the press plates made of chemically tempered glass. The disc had a nominal thickness from 3 »2 mm. The surfaces of the pane made of dom polycarbonate were polished under pressure to the extent that extrusion lines visible on the original flat disk matched the invisible to the naked eye.

In the case of the original flat disk, the distortion bands disappear at a distance of the pane from the screen of 15 em. After the treatment described, the distance was between

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the
62 and 69 ent when / convex surfaces of the disc are in the screen

was.

Example II

The procedure of Example I was repeated with the exception that the polycarbonate pane had a size of 143 x 112 cm, since it was to be used as a window for the aircraft F-111. The disk made of the polycarbonate was brought into the desired shape by the treatment box according to the invention at a temperature of 120 to 150 ° C. at atmospheric pressure, in that it could be bent by gravity. The final molding was carried out for 90 minutes at a temperature of 150 ° C. and a pressure of Ik kg / cm ". During the first molding, the surface of the polycarbonate pane was not noticeably changed. After polishing under pressure, however, the shape and the optical properties were improved In this case, the press mold had complementary press plates which were bent conically to a right angle.

In the original flat disc, the distortion bands ^{disappeared at a distance of Ϊ5 cm} from the screen, after the first bending at a distance of 18 to 23 cm from the screen and after the treatment according to the invention at a distance of 150 cm from the screen.

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Bo: im) iol II I

There were two polycarbouat-Schoiben with about 6o χ 6θ cm groove Vetches of 3> ^ or 6.3 mm in front of them. Any of these slices was initially at a temperature of 150 C on a cylindrical Surface made of chemically tempered glass treated in such a way that they took on the cylindrical shape of the glass. then the two disks were placed in layers one on top of the other. These two panes were brought together "wipe two." Rigid Plufcten made of chemically strengthened glass with thicknesses of 4.7 mm, their corresponding smooth surfaces by two Axes were bent so that there was glazing for the aircraft F-11.1 could arise. The Gmiao was made into a pliable Ueu'ü.1 from an impermeable to 01 and liquids]) Brought substance that was evacuated and closed. In one Au toc Laven was initially responsible for the whole thing at JjO C

pressure from 1.0 to 1.8 kg / cm treated. Then the temperature in the autoclave was increased to 150 ° C., the pressure being reduced during was held at 1.8-315 kg / cm for about 30 minutes.

The pressure was then increased to 1 l kg / cm, and at this temperature and this pressure it was 2 ^ 1-0 minutes go »1 Len.

Al i; As a result, a sheet made of ßjneru l'olycarbonate with a thickness of 9-5 mm and a size of about 60 χ G <) cm was obtained by welding. The curve corresponded to that

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the rigid press board. The pane had good transparency and optically smooth surfaces. With the original Flat disks made of the polycarbonate disappeared the venom bandon in. and? Distance of 15 cm from the Schix'in. } 3ei the end product, the distortion bands disappeared in one Distance from 35 to 4 3 cm.

Example IV

Two disks made of Polycarbormt with a thickness of 6.3 mm and a Liclite permeability of 82 % were put together and treated between flat press plates as described in Example III. The laminated body obtained had a thickness of 12.7 mm and a light transmittance of 79%. In the case of the untreated panes, the distortion bands disappeared at a distance of 15 cm from the screen, while this distance was 63 to 76 cm for the end product.

Example V

A stretched disk made of modified methyl methacrylate (Plexiglas 55) was placed between two rigid press plates made of chemically strengthened glass with the desired shape. In an evacuated and sealed flexible bag as described in Examples I to IV, the whole thing was in an autoclave)! initially at ^ O C and an overpressure

£ 09829/0924 ^ ₀ original

ο
treated of 1.75 kg / cm "While another 20 Mi nut on \ -mrde then the autoclave at 1055 C heated The Di'uck was increased to lh kg /, and the whole was during 6θ minutes at this:.. pressure and The polyncryl sheet treated in this way had improved optical properties, smooth surfaces.

surfaces and the desired shape.

Example Vl

Three 6θ χ 6θ cm thick polysarbonate discs of 6.3 or 3i2 or 6.3 mm were individually pre-deformed Heating between cylindrical surfaces made of chemically annealed Glasses. The temperature was increased to 150 ° C. during this process and the heating was continued until the slices had the desired shape.

The curved disks were then placed overlying each other with the edges aligned. They were taken between two press plates made of chemically tempered glass having a thickness of k, 8 mm and complementary with smooth surfaces the desired shape. A thin, flexible sheet of red cellophane was placed between the press plates and the laminate as a separating material. The whole was then placed in a flexible bag, which was evacuated and closed. In an autoclave it was heated to about 50 ° C. next time. Then, within 55 to 60 minutes, a pressure of 1.7 to 3.5 kg / cm

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BATH

the temperature increased to 195 C. Then at this group

for 4 hours under a gin pressure of Ik kg / ciü ". After cooling and releasing the pressure, the contents were removed from the bag. A welded, transparent laminate was created, the distortion elements in one."

Distance of more than 61 cm from the screen disappeared while in the case of the original discs this distance IfJ. cm fe fraud. The surface of the laminate, however, was somewhat miregeli-like. These irregularities were removed by polishing under pressure according to the method of the Canadian patent specification No. 857i759 »i.e. another pressing between the Press plates without release agent. The renewed pressing wm-de 90 Mi.mi-

performed under a pressure of 14 kg / cm and at a temperature below 150 ° C. for a long time. The optical distortion bands disappeared at a distance of more than 100 cm from the laminate from the screen.

The disks made according to these examples were then ready for the production of laminated glass.

A preferred method for this is that the so The resulting panes are connected with a transparent pane of glass or a glass substitute, with as an intermediate layer a plasticized polyvinyl butyral is used.

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BATH ORIGINAL

The production of the layer is done so that the whole thing is pressed in an evacuated and sealed flexible bag of the type described at elevated temperature under pressure. Good results are obtained at a temperature of 135 ° C. and a pressure of 1Ί kg / cm for ky minutes.

The experiments described in the examples were carried out on various Repeated temperatures and pressures with the same and other polycarbonates with or without a release agent. It was it is established that it is necessary not to adjust the pressing pressure z \ i to keep high as long as the workpiece does not reach the maximum working part temperature has reached, especially when the press plates have a different shape than that to be processed Workpiece. Without this precaution, fractures could occur .

Below are the working temperatures for polycarbonates and elongated panes made of polyacrylic compounds are given at which molding and polishing can be carried out at the same time under high pressure without the good optical properties Attributes are lost.

Stretched discs made of methyl methacrylate 88 - 104 C Polycarbonate without release agent 121 -

Polycarbonate with separator 121 -

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The workpieces should be heated as quickly as possible, but not so quickly that thermal stresses occur in them. Heating rates of 3 to Ik C each are suitable. Minute.

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Claims (1)

- 43 patent claims Method for treating a transparent pane or Plastic film with an optically imperfect surface for the purpose of optically improving the surface and for the purpose of converting it into the desired shape, thereby characterized in that one the film between two smooth rigid press plates of the desired shape under relatively Heated so high under low pressure that the disc or film receives the desired shape, then with this Temperature increased the process pressure, and removed from the press after cooling. 2. The method according to claim! that the press plates and the one to be handled Disc odex "foil during heating and pressing" in an evacuated and tightly sealed bag made of a thin, flexible, impermeable to liquids Material lasts. 3. The method according to claim 1 or 2, characterized in that the disc or film is brought into approximately the desired shape before being introduced between the press plates. 209829/0924 BATH ORIGINAL '}. Ancestors according to one of claims 1 to 3, characterized in that it is done with one at the
Disc or film and non-adhering substance to the press plates between these two passes. 5. Method according to one of claims 1 to k, characterized characterized in that, for the treatment of a pane or film made of a polycarbonate, this under an overpressure of about 3> 5 kg / cm in an hour by 3 to Ik C Rr- heated and then under an overpressure of more than 7 kg / cm presses at about 120 to about 150 ° C. 6. The method according to any one of claims 1 to 4, characterized characterized in that one is used to treat a stretched sheet or film made of a polyacrylic compound · ■ 2 this is heated every minute by 3 to 1Λ C under an overpressure of about 3.5 kg / cm and then under an overpressure of
more cils 7 kg / cm "at about 8> to about 105 ° C. 7 * Method according to one of claims 1 to 6, characterized characterized by treating two or more slices one on top of the other at such a high temperature, that their surfaces are welded together. 209829/0924 I ₁₅ - 8. The method according to claim 5 for producing οinor from jwei or multiple layers of a polycarbonate Laminated body according to claim 7> d a d u r c h g e k e η η-draws, that the compression pressure of inch * - than 7 kg / cm is maintained for at least 30 minutes. 9 · The use of a pane produced according to one of claims 1 to 8 made of a polycarbonate with a thickness of at least 10 minutes as a window pane. 10. Use according to claim 9 as part of a laminated glass together with a disk made of Silikatglan, a polyacrylic compound or a polycarbonate and together with an intermediate layer. 11. Use according to claim 10, d a d u r c h g e k e η η-records, that the civil class consists of a polyvi- | nylacetal or a polyurethane. BAD ORIGINAL 209829/0924