DE1292811B - Use of copolymers as adhesive films for laminated safety panes - Google Patents

Description

The invention relates to the use of certain copolymers as adhesive films for laminated safety panes made of glass plates and plates made of high molecular weight organic materials.

Laminated safety panes made from glass plates and plates made from high molecular weight Polycarbonates of dihydric phenols, such as those used, for. B. from the French patent 1,390,046 and British patent specification 1,053,220 are known through particularly advantageous properties. For automobile windshields such composite safety panes of the type mentioned are particularly suitable, where the thickness of the glass plate and the polycarbonate plate in a certain Are related to each other (see Belgian patent 686 124).

To the adhesive layer of such composite safety panes, the z. B. Glass plates and plates made of high molecular weight organic materials such as polycarbonates, connect with each other and whose thickness is between about 0.05 and about 1 mm, are to make a variety of demands. The adhesive layer should be one over one have the widest possible temperature range as constant a cohesion value as possible, in order to be able to absorb the stresses that arise during temperature changes due to the strong different temperature expansion coefficients of glass and organic material occur, which is by the way not too small to provide sufficient cohesion of the laminate, especially at higher temperatures, but also is not too high to prevent stress fractures from occurring, especially in the case of low Temperatures, to prevent; also a sufficient adhesive force with respect to the two layers to be connected. In addition, the adhesive layer must not be significant Solvent and monomer residues and plasticizers because contain such ingredients would attack the organic material. In the interest of easy processability the adhesive should also be in the form of an easy-to-handle, self-supporting film are present with plane-parallel surfaces, which despite good adhesion to the to be connected Layer should not be sticky at room temperature if possible, so when laying on the film on one layer and when covering it with the other layer there are no wrinkles and no cavities or

Air bubbles arise at elevated temperature and possibly below But stick the pressure well and then the layers even at normal and low temperatures keep them firmly connected. Also required are: Complete optical Clarity and colorlessness, which is also under the influence of heat and of light and In particular, ultraviolet rays are retained, and complete chemical neutrality with respect to the organic material, to avoid dissolving or swelling and thus possibly to exclude the formation of stress corrosion cracks or the occurrence of cloudiness, finally extensive resistance to water or humidity and chemical resistance Agents.

For the production of composite safety panes that are only made from one another connected glass plates are already a very large number of adhesives or adhesive films have been proposed. The modified ones containing plasticizers are best known Polyvinyl acetal films, which are generally made from for the production of safety panes Glass / glass be used. In U.S. Patent 3249490, e.g. B. the use of triethylene glycol di-2-ethylbutyrate as a plasticizer for such acetal foils Achieving sufficient flexibility is described. According to the USA patent 3 249 487, column 7, line 14, is the use of triethylene glycol di-2-butyrate, -dibutyl sebazate and -di-B-butoxyethyl adipate known as plasticizers for such films. The use of esters of phthalic acid with higher aliphatic, straight-chain or branched alcohols, such as dioctyl phthalate, as plasticizers for Polyvinyl butyral films with which glass-glass composite panes are produced.

For the production of a composite of glass and high molecular organic Such plasticizer-containing films are not suitable, however, since the Plasticizers swell the high molecular weight organic material, which after a short time Time leads to stress corrosion cracking.

The use of copolymers - the esters - is also known acrylic and methacrylic acid as an intermediate layer for security panes. So concerns z. B. the German patent 660 634 a method for the production of clear transparent safety glass made of glass panes, which is characterized by that the layers connecting the glass panes are made of rubber-like elastic Films made from polymerization products of the ethyl or methyl ester of acrylic acid exist and that the films are produced by polymerization between the glass plates will.

The copolymerization of, for example, butyl acrylate is also known, Vinyl acetate and acrylic acid methyl ester between two glass plates for production of laminated glass (see German patent specification 674 712).

For the production of laminated safety panes from glass is still a very large number of adhesives made from polymerizable esters, has been proposed (see e.g. Kunsrstoffe, 23 [1933], pp. 121 to 163, and Kolloid-Zeitschrift, 98 [1942], pp. 117 to 127 and 376 to 384).

From the large number of glass-glass laminated safety panes for one use However, known polymers are used as adhesive layers for composite safety panes made of glass plates and high molecular weight organic materials only a few in Question, whereby it can usually not be predicted which polymers will come from the multitude are now suitable.

Adhesive films containing no plasticizers, which are used for the production of Safety glass that can be used can be made from partially hydrolyzed Manufacture ethylene-vinyl ester copolymers.

Such films show in the production of laminated safety glasses However, high molecular weight organic materials and glass have the disadvantage of increasing poor adhesive strength and tendency to become brittle at temperatures below 0 ° C or prolonged stay in the open air.

Surprisingly, it has now been found that for the production of Laminated safety panes made of glass and high molecular weight organic materials just such copolymers are excellently suitable as adhesive films, the from vinyl esters with 2 to 4 carbon atoms in the acid residue, acrylic acid esters with 1 to 4 C atoms in the alcohol group as well as methyl methacrylate and by means of suspension polymerization manufactured have been, the acrylic acid esters in an amount of 25 to 70 percent by weight, the vinyl esters in an amount of 5 to 70 percent by weight and the methyl methacrylate have been used in an amount of 5 to 30 percent by weight. The percentage The composition of the copolymers to be used according to the invention is also off can be seen in the attached triangle diagram. The copolymers according to the invention have a relative viscosity of about 1.25 to about 2.56, but preferably of about 1.62 to about 2.15 (measured as a 0.5% solution in chloroform at 200 C), and a refractometrically determined freezing temperature of -5 to -26 "C, preferably from -12 to -20 "C, on.

The present invention thus relates to the use of Copolymers of 5 to 70 percent by weight vinyl esters with 2 to 4 carbon atoms in the acid residue, 25 to 70 percent by weight of acrylic acid esters with 1 to 4 carbon atoms in of the alcohol group and 5 to 30 percent by weight of methyl methacrylate with a relative Viscosity from about 1.25 to about 2.56, preferably from about 1.62 to about 1.90 (measured as a 0.5% solution in chloroform at 20 ° C), and one refractometric certain freezing temperature from -5 to 260 C, preferably from -12 to -20 "C, as adhesive films for laminated safety panes made of glass plates and plates made of organic high molecular weight material, their impact strength, measured according to DIN 53453 at room temperature and -20 "C, results in no breakage of the sample, preferably polycarbonates on the base of 4,4'-dihydroxydiphenylalkanes, aromatic polysulfones or polyphenylene oxides.

The copolymers to be used according to the invention are produced by suspension polymerization in a manner known per se. As protective colloids are suitable e.g. B. both water-soluble macromolecular compounds, such as methyl cellulose, completely or partially saponified polyvinyl acetates, polyacrylates or polyglycols and finely divided water-insoluble minerals alone or in combination with one another. The volume of the aqueous phase in relation to the mixture of monomers can be change, as is known with respect to polymerization systems in aqueous suspension is. The most suitable is the use of 2 to 5 parts by volume of the aqueous phase to 1 part by volume of the monomer mixture. All common, Free radical formers soluble in the monomers, such as azo compounds, peroxides or peroxydicarbonates, in question. Mercapto or xanthogen compounds are preferably used as regulators. Around to suppress emulsion polymerization, which leads to a decrease in yield leads, water-soluble polymerization poisons, such as copper salts or for example Ammonium rhodanide, can be added. The polymerization is expediently under Nitrogen at temperatures of 40 to 90 "C carried out.

The resulting from the polymerization beads are in the usual Way separated, washed and then dried.

That which is preferably dried to a residual water content of 0.2% Bead polymer can be produced in a manner known per se either by casting from solutions or by extruding the polymer melt with the aid of a slot die be formed into foils of any width and thickness per se the. The set The gap width of the nozzle, the take-off speed and, if applicable, a subsequent one Calendering determines the thickness, type and quality of the surface of the film.

The new adhesive films are self-supporting and at room temperature hardly sticky, have practically plane-parallel surfaces that may be light structured, for example grooved, and a thickness of about 0.1 to 2, preferably 0.4 to 1 mm.

To improve the handling of the film during manufacture, transport and further processing, a thin, non-adhesive layer can be applied.

With this self-supporting adhesive film, the to be connected Materials can be connected to one another without bubbles in a simple manner by insert the cut-to-size film between the laminates to be joined and then the laminate to about 80 to 150 "C, usually under pressure, e.g. B. gas or liquid pressure or between press plates or rollers, if necessary, but also under vacuum, heated. At this temperature the adhesive force becomes effective, and there is a permanent, intimate, bubble-free connection between the materials. In this way, glass can be made with transparent high molecular weight organic materials be cemented. Laminates made up of more than three layers can also be produced in this way will.

As high molecular organic materials to be bonded with glass In general, organic materials come into question whose impact strengths, measured according to DIN 53453 at room temperature and -20 "C, the sample does not break, but preferably high molecular weight aromatic polycarbonates, polysulfones and polyphenylene oxides.

Suitable polycarbonates are, for. B. those based on 4,4'-dihydroxydiphenylalkanes, such as 4,4'-dihydroxydiphenyldimethylmethane, e.g. B. according to the Belgian patent 532 543 can be produced. The diphenyl sulfones are aromatic diphenyl sulfones, the z. B. by reacting 4,4'-dichlorodiphenyl sulfone with 4,4'-dihydroxydiphenyldimethylmethane are produced, in question, the z. B. according to Dutch patent 6 408 130 can be produced.

For the manufacture of windshields for motor vehicles is the cementing of glass with polycarbonates is particularly advantageous, the inventive self-supporting adhesive film enables visually perfect bonding.

In the table below are the test results of some Composite panes summarized.

The impact tests were carried out with a 2.268 kg steel ball 30 30 cm large test panes, consisting of a pane of glass, which by means of various Adhesive foils either with a second sheet of glass of the same thickness or with one Disc made of organic material are cemented.

The direction of impact was chosen so that it turned away from the falling weight Side was always a pane of glass. The experiments were carried out at room temperature and at -15 "C made.

The impact energies were 2.0, 5.0 and 10.0 mkp.

The composite panes made of glass and polycarbonates were even rated at 15 mkp charged.

The results in the table also show that an off Laminated safety glass made from a polyvinyl butyral film for glass and polycarbonates already is damaged or broken in the event of a low impact load, which is due to the harmful The effect of the commercially available polyvinyl butyral films can be traced back to the polycarbonate pane is, while that produced by means of the adhesive films to be used according to the invention Laminated safety glass even with very high impact loads, even at -15 "C, not gets destroyed. (Trials No. 3 to 9).

Impact tests on laminated safety glass. Size of the test discs: 30 # 30 cm, restraint: wooden frame, falling weight: steel ball weighing 2.268 kg. Temperature temperature Construction of the composite pane 220C -15 "C such burden burden No. - Bottom Thick Top Thick Adhesive Foil Thickness mkpl mkp mm [mmj [mml 2 5 10 15 2 5 10 15 1 mirror glass 3.0 mirror glass 3.0 polyvinyl butyral 0.38 + - - 2 mirror glass 3.0 mirror glass 3.0 polyvinyl butyral 0.76 + + - + + - 3 Mirror glass 3.0 poly 1.0 polyvinyl butyral 0.38 + + - + - carbonate *) 4 Mirror glass 3.0 poly 1.0 mixed polyacrylate 0.38 + + + + + + + + carbonate *) polymer 5 Mirror glass 3.0 poly 1.0 polyacrylate mix 0.5 + + + + + + + + carbonate *) polymer 6 Mirror glass 3.0 polysulfone **) 1.0 mixed polyacrylate 0.5 + + + + + + + + polymer 7 Mirror glass 3.0 polyphenylene 1.0 polyacrylate mixture 0.5 + + + + + + + A oxide polymer 8 mirror glass 3.0 polymethyl- 1.0 polyacrylate mixture- 0.5 methacrylate polymer 9 thermal 4.0 poly 1.0 polyacrylate mix 0.5 + + + + + + + + pre-stressed carbonate *) polymer Mirror glass 10 thermal 6.0 poly 1.0 polyacrylate mix 0.5 + + + + + + + + pre-stressed carbonate *) polymer Mirror glass -Discharge. *) Manufactured on the basis of 4,4'-dihydroxydiphenyldimethylmethane.

+ No breakthrough. **) Manufactured on the basis of 4,4 ~ dichlorodiphenyl sulfone.

Example 1 Saponified for the most part using 3.5 g of one Polyvinyl acetate per liter of water, 0.5 percent by weight benzoyl peroxide and tert-dodecyl mercaptan A bead polymer is used as a regulator at a phase ratio of 1: 4 (monomer to water) of 66.5 percent by weight ethyl acrylate, 27 percent by weight vinyl acetate and 6.5 percent by weight Methyl methacrylate with a relative viscosity of 2.434 and a glass transition temperature from -16 ° C. The dried bead polymer becomes about 20% strength Solution made in methylene chloride and cast a film on a glass plate, which, after evaporation of the solvent and drying in vacuum, has a thickness of 0.4 mm. A plate of the same size, 1.0 mm thick, is now placed on the adhesive layer of 4,4'-dihydroxydiphenyldimethylmethane polycarbonate with a relative viscosity of 1.32, measured in a 0.5% methylene chloride solution at 25 "C, and under pressure at elevated temperature to a firmly adhering, clear transparent Compressed composite pane, the z. B. suitable as a windshield for motor vehicles is.

Example 2 Using 0.5 g of a heavily saponified polyvinyl acetate and 6 g of magnesium hydroxide per Liter of water as protective colloid becomes a pearl polymer of 66.4 percent by weight ethyl acrylate, 20 percent by weight vinyl acetate and 13.6 percent by weight Methyl methacrylate with a relative viscosity of 1.7123 and a glass transition temperature produced from -20 ° C.

The dried, clear, transparent bead polymer is on a with a slot die provided screw press at 160 "C to a 0.5 mm thick film extruded. To allow better handling of the film during transport ensure and to prevent contamination, the film is put together wound up with an adhesive film.

On a 30 cm large, 3.0 mm thick mirror glass plate is a 30 # 30 cm section of the adhesive film is applied. A 30 - 30 cm large, 1.0 mm thick plate made of 4,4'-dihydroxydiphenyldimethylmethane polycarbonate with a relative viscosity of 1.30, measured in a 0.5% methylene chloride solution at 250 C. This three-layer system is then in the autoclave at reduced Pressure kept for some time at elevated temperature and then at room temperature and normal pressure let come. It becomes a clear, transparent composite pane obtained that even when cooling to # 25 ° C, despite the difference by a factor of 10 thermal expansion coefficient of polycarbonate and glass, is not destroyed.

Performing the ball failure attempt at -15 "C takes place automatically with a shock load of 15 mkp no breakdown. The disc can e.g. B. as a windshield used for automobiles.

Example 3 The procedure is as in Example 2, but one is used 5 mm thick plate made of toughened mirror glass. Also the composite pane obtained in this way withstands cooling to -25 "C. It is also used as a windshield for Suitable for motor vehicles.

Example 4 A 3 mm thick mirror glass plate, an adhesive film, a 0.8 mm thick polycarbonate sheet, made on the basis of 4,4'-dihydroxydiphenyldimethylmethane, Another adhesive film and another 3 mm thick mirror glass plate are stacked on top of one another and, as described under 1, combined to form a composite pane. This disc too can Can be cooled to -25 "C without damage and is suitable as a safety disc.

Claims (1)

Claim: Use of copolymers from 5 to 70 percent by weight Vinyl esters with 2 to 4 carbon atoms in the acid residue, 25 to 70 percent by weight of acrylic acid esters with 1 to 4 carbon atoms in the alcohol group and 5 to 30 percent by weight methyl methacrylate having a relative viscosity of about 1.25 to about 2.56, preferably about 1.62 to about 2.15 (measured as a 0.50 / 0 solution in chloroform at 20 ° C), and one refractometrically determined freezing temperature of -5 to -26 "C, preferably from -12 to -20 "C, as adhesive films for laminated safety panes made of glass plates and Sheets made of high molecular weight organic material with impact strengths that are measured according to DIN 53453 at room temperature and -20 "C, the sample does not break, preferably Polycarbonates based on 4,4'-dihydroxydiphenylalkanes, aromatic polysulfones or polyphenylene oxides.