CS261870B2 - Manufacture of foil from transparent plastic material - Google Patents

Description

A method for producing a transparent plastic film of high optical quality by producing a layer having energy-damping properties by reactively casting a reaction mixture of an isocyanate component having a viscosity of less than 5 Pa. . at a temperature of +40 ° C with a polyol silage on a horizontal support, the isocyanate component comprising at least one aliphatic or cycloaliphatic diisocyanate or isocyanate prepolymer and the polyol component comprising at least one long difunctional polyol having a molecular weight of 500 to 4000 and at least one short diol such as the chain extender, and the ratio of the number of equivalent isocyanate groups to the number of equivalent hydroxyl groups is in the range of 0.9 to 1.1, and the relative amounts of the individual polyols are selected such that the number of equivalent hydroxyil groups introduced by the short diol is 20 to 70% hydroxyl groups, whereupon the layer is polymerized on a horizontal flat support.

281870

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the manufacture of a film of transparent plastic of high optical quality, comprising a polylyurethane-based layer having energy absorber properties, which film can be used alone or in conjunction with other materials, particularly for the manufacture of laminated glass panes consisting of glass and at least one plastic layer, for example in the manufacture of vehicle windscreens.

Plastic films have already been proposed which can be used in laminated glass panes of the type described. Thus, French Patent No. 2,398,606 discloses a two-layer film, one of which is a thermoplastic mass layer which, when used in laminated glass panes comprising a single sheet of glass, is an intermediate layer having energy absorber properties, and the other layer is a layer of thermosetting, self-sealing, tear-resistant plastic.

The intermediate layer having energy absorber properties is a layer of thermoplastic polyurethane made of at least one aliphatic diisocyanate and at least one polyester diol or polyether diol, the ratio of the number of equivalent NCO groups to the number of equivalent OH groups preferably being in the range of 0.8 to 0.9. A laminated glass sheet in which such a two-layer film is used retains its good optical properties and the cohesion of its components remains good under very variable temperature and humidity conditions, but biomechanical properties, in particular impact resistance (impact strength) of the laminated glass sheet are not entirely satisfactory.

European Patent Specification 0 054 491 discloses a two-layer film which can be used for the production of a laminated glass sheet having the structure described above, the intermediate layer having energy absorber properties and is formed of a polyurethane-urea having a linear structure and having a urea group content by weight of from 1 to 20%. This polyurethane-urea is the reaction product of a prepolymer made of a polyol component and an excess of an isocyanate component with at least one diamine. This intermediate layer having the energy absorber properties is obtained by extruding a polyurethane polyurea resin or by casting a solution of the resin and evaporating the solvents, which in both cases requires several successive manufacturing operations.

In the case of extrusion, the resin must be preformed to extrude.

In addition, in order to achieve the optical quality required for the intended use, the produced film must be "remanufactured", since the plastic retains the way it is produced and the quality of the "remanufactured" deteriorates over time.

In addition, joining an extruded layer having energy absorber properties to a self-sealing layer presents a number of problems.

If the solution is cast, it is also necessary to first synthesize the resin, then dissolve it in a solvent, pour the resulting solution onto a carrier and evaporate the solvent, which must be repeated until a layer of suitable thickness for the intended use as an energy absorber is formed. Also, solvent evaporation is another source of trouble.

The invention therefore provides a novel process for the production of a high optical quality transparent plastic film comprising a polyurethane-based layer having energy absorber properties, which process is characterized in that the layer having energy absorber properties is produced by reactively casting a reaction mixture of an isocyanate component having a viscosity lower than 5 Pa. s at +40 ° C with a polyol component on a flat horizontal support, wherein the isocyanate silage comprises at least one aliphatic or cycloaliphatic diisocyanate or prepollymer diisocyanate and the polyol component comprises at least one long difunctional polyol having a molecular weight of 500 to 4000 and at least one short diol, as a chain extender, and the ratio of the number of equivalent isocyanate groups to the number of equivalent hydroxyl groups is in the range of 0.9 to 1.1 and the relative amounts of the individual polyols are chosen such that the number of equivalent hydroxyl groups introduced by the short diol is 20 to 70% the number of hydroxyl groups, whereupon the layer is polymerized on a horizontal support.

By reactive casting is meant pouring a liquid mixture of the monomer or prepolymers components into a layer or film sheet, followed by polymerization of the mixture by heat treatment. This reactive casting, which confers good mechanical and optical properties to the layer, is explained in more detail below.

The relative amounts of the individual polyurethane components are selected so as to obtain a stoichiometric balanced system, i.e., the number of equivalent NCO groups introduced by the diisocyanate component, to the number of equivalent OH groups introduced by the polyol component, i.e. long or long poilyols and short or short diols. was equal to 1. When the NCO / OH ratio is less than 1, the mechanical properties required for the intended use quickly become less satisfactory, the lower the ratio. When all the components of the polyurethane are difunctional, the lower limit of the NCO / OH ratio is about 0.9 to obtain satisfactory mechanical properties. When the ratio value. NCO / OH is higher than 1, some mechanical properties of the layer produced by reactive casting the better the value of this ratio is, for example the layer becomes stiffer; and

However, since the cost of the isocyanate silica is higher than the cost of the polyol component, the choice of an NCO / OH ratio of about 1, i.e., in the range of 0.9 to 1.1, is a good compromise between the properties achieved and the cost.

The proportions of long podol and short diol are chosen such that when the ratio of the number of equivalent NCO groups to the number of OH groups is approximately equal to 1, the number of equivalent OH groups introduced by the short diol is generally 20 to 60% folder. When the relative amount of short diol is increased, the layer becomes harder and generally increases its modulus.

Diisocyanates suitable for use in the present invention are preferably selected from the following difunctional aliphatic isocyanates:

hexamethylene diisocyanate (HMDI),

2,2,4-trimethyl-1,6-hexanediisocyanate (TMDI), bis- (4-isocyanatocyclohexylmethane (Hyléine)

W) bis- (3-methyl-4-isocyanatocyclohexylmethane)

2,2-bis - <(4-isocyanatocyclohexyl) -propane, 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (IPDI), m-xylylene diisocyanate (XDI), m- and p-tetramethylxylylene diisocyanate (m- and p-TMXDI) ), tirane-cyclohexane-1,4-diisocyanate (CHDI) a

1,3- (diisocyanatomethyl) -cyclohexane (hydrogenated XDI).

Preferably, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI) is used, especially for its cost.

According to one variation of the invention, an isocyanate component comprising urea groups is used. These urea groups improve some of the mechanical properties of the layer. The relative amount of urea may be up to about 10% of the total weight of the isocyanate component with urea groups. Preferably, the relative amount of urea is 5 to 7% of the total weight of this component. For the above-mentioned reason, urea-scalp-containing 3-isocyanatomethyl-3,5,5-trimethylcyclohexyldiisocyanate (IPDI and its derivatives) is preferably used.

Suitable long polyols are selected from polyether diols or polyester diols having a molecular weight of 500 to 4000; polyesterdioils are esterification products of a dicarboxylic acid, for example adipic, succinic, palmitic, azeilaic, sebacic or o-phthalic acid, a diol, for example ethylene glycol,

1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, polyether diols of general formula

HE 0- (CH _a) 3 _m 0H in which n is 2 to 6 am has a value such that the molecular weight is in the range of 500 to 4000, or a polyether of the formula

Γ i ³ ΊH OCH - CH, OH in which m has a value such that the molecular weight is also in the range of 500 to 4,000.

Polycaprolactondiols may also be used.

Preferably, polytetramethylene glycol (n = 4) having a molecular weight of 1000 is used.

Preferred chain extenders are short diodes having a molecular weight of less than about 300, preferably less than 150, such as ethylene glycol,

1,2-propanediol, 1,3-propanediol, 1,2-, 1,3-a

1,4-butanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol , cyclohexanedimethanol, bisphenol A, 2-methyl-2,4-pentanediol, 3-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanedioil, 2,2,4-trimethyl-1,3-pentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, 2-butyne-1,4-diol, 1,4-butenediol and decindiol, substituted and / or etherified, hydroquinone-bis-hydroxyethyl ether, bisphenol A, etherified with two or four propylene oxide groups, dimethylolpropionic acid. Generally, the shorter the diol, the harder the layer.

Preferably, 1,4-butanediol is used, which represents a good compromise to obtain a layer that is neither too hard nor too resilient, such as is suitable for this type of use as an energy absorber.

One feature of the layer having energy absorber properties is that according to the invention it is produced by reactive casting on a flat horizontal support. Surprisingly, according to the invention, in the case of difunctional starting materials, this reactive casting, one form of which has already been described, for example, in French Patent No. 2,442,128 for producing a polyurethane heat-curable layer from a mixture of trifunctional components, provides a layer which is not entirely thermoplastic. the NCO / OH number ratio is practically equal to 1.

Reactive casting involves rapid reaction or polymerization to form the layer in a time acceptable for industrial scale production. This requires the use of a higher temperature, in the range of about 100 to 140 ° C, at which side reactions occur to form branched products, for example, allophanate and / or biuret groups are formed between the urethane chains as illustrated by the following schemes:

, - R — NH — CO — O — R‘ — O—

OCN — R — NCO

--R — NH — CO — O — R‘ — O-I 's-r / n-co-o-r-o · - t' I / s,.

/ I 'and tt o fa n a t.

NH / CO, - R - N - CO - R - O - or

- R '—ΝΗι — CO — NH — R “—OCN — R — NCO

--R “—NH — CO — NH — R“ -R F N - CO-NHyR / co / k

NH cp

R-N-CO-NH-R ^? '

Under these reaction conditions, even using difunctional components, when the NCO / OH ratio is practically equal to 1, as mentioned above, the resulting product is not entirely thermoplastic; indeed, it is non-fusible and insoluble in most polyurethane solvents such as tetrahydrofuran or dimethylformamide. This is not a problem, however, since the layer is already formed; on the contrary, this results advantageously in improved mechanical properties compared to an equivalent low temperature polymerized system at which only linear polycondensation occurs.

When the NCO / ON group number ratio is less than 1 and in the range of 0.8 to 0.9, crosslinking of the above type occurs only to a minor extent.

In one variation of the polyurethane layer having energy absorber properties, the polyol component may comprise a small proportion of at least one polyol having a functionality greater than 2, particularly monomeric aliphatic trioles such as glycerol, trimethyilolpropane, polyether chain triols, polycaprolactone triols, it is usually in the range of 90-1000, mixed polyether / polyester polyols having a functionality of greater than 2, for example a functionality in the range of 2 to 3. Addition of a polyol of functionality of more than 2 induces additional bridging between the polyurethane chains. consistency of the layer.

The relative amounts of long polyol, short diode, and optionally polyol of functionality greater than 2 may vary according to the desired properties. Typically, these amounts are chosen such that from one hydroxyl equivalent, the long polyol is about 0.30 to 0.45 equivalents, the short diol is about 0.2 to 0.7 equivalents, and the polyol has a functionality greater than 2 about 0 to 0 , 35 equivalents. Under these conditions, the layer is characterized by the following mechanical properties, measured according to AFNOR / NFT standards 46 002, 51 034, 54 10'8:

- a stress and strain point r _y at –20 ° C of not more than 3 daN. mm ^-2 , - tear at t _r at +40 degrees Celsius at least 2 daN. mm ^"2 - with _R ductility at 20 ° C in the range from 250 to 500%, - tear resistance R _and + 20 ° C of at least 9 daN. mm ^-1 thickness.

The layer may also be formed by replacing part of the polyol component with a compound with active hydrogen, such as an amine.

In another variation of the embodiment of the plastic layer according to the invention, the isocyanate component may comprise, to a limited extent, for example less than about 15% of HNCO equivalent, at least one triisocyanate such as isocyanate biuret or triisocyanurate.

In one embodiment of the invention, the film is formed from the layer described above. This layer has, in addition to the energy absorber properties as mentioned above, a good scratch and abrasion resistance which makes it suitable for use as the outer layer. Its scratch resistance, as determined by the test described below, is greater than 20 g, and its abrasion resistance, as determined by the following test and expressed as a matt difference, is less than 4%.

In order to meet all the requirements imposed on it, the layer according to the invention should have a thickness generally higher than 0.5 mm, preferably higher than 0.6 mm.

In another embodiment, the film produced by the method of the invention comprises, in addition to the layer described above, a layer of self-absorbable plastic, i.e., scratch and abrasion resistant.

A scratch-resistant, self-sealing plastic layer, which may also be referred to as the inner protective layer (layer P 1) due to its use according to the invention, is described, for example, in French Patent Nos. 2,187,719 and 2,251,608. high elastic deformation under normal temperature conditions, low modulus, less than 2000 daN. . tin ^-2 and preferably less than 200 daN. cm ² , and an elongation greater than 60%, preferably greater than 100%, with plastic deformation less than 2%, preferably less than 1%. Preferred layers of this type are thermoset polyurethanes having an elastic modulus of about 25 to 200 daN / cm ² and an elongation of about 100 to 200% with a plastic deformation of less than 1%.

Examples of monomers suitable for the preparation of these thermoset polyurethanes are aliphatic difunctional isocyanates such as:

1.6- hexane diisocyanate,

2.2.4-trimethyl-1,6-hexanediisocyanate,

2,4,4-trimethyl-1,6-hexanediisocyanate, -1,3-bis- (isocyanatomethyl) benzene, bis- (4-isocyanatocyclohexyl) methane, bis- (3-methyl-4-isocyanatocyclohexyl) methane, 2,2 -bis- (4-isocyanatocyclohexyl) propane and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, as well as the biurets, isocyanurates and prepolymers of these compounds having a functionality of at least 3, on the other hand polyfunctional polyols such as branched polyols, e.g. reactions of polyfunctional alcohols, in particular:

1.2.3- propanetriol (glycerol),

2,2-bis- (hydroxymethyl) -1-propanol (trimethylolethane),

2,2-bis- (hydroxymethyl) -1-butanol (trimethylolpropane),

1.2.4- butanetriol,

1.2.6- hexanetriol,

2,2-bis- (hydroxymethyl) -1,3-propanediol (pentaerythritol); and

1.2.3.4.5.6- hexanhexol (sorbitol) with aliphatic dicarboxylic acids such as malic acid, succinic acid, glutaric acid, adipic acid, corkic acid and sebacic acid, or with cyclic ethers such as ethylene oxide,

1,2-propylene oxide or tetrahydrofuran.

The molecular weight of the branched polyols is preferably in the range of about 250 to 4000, in particular in the range of 450 to 2000. Mixtures of various polyisocyanates and monomeric polyols can be used. A particularly preferred heat-curable polyurethane is disclosed in French Patent No. 2,231,608.

Important parameters are the thickness of the energy absorbing layer (AE layer) and the thickness of the self-healing layer of the PI layer and the ratio of the two thicknesses. According to the invention, the total thickness of the two superposed layers should be greater than 0.5 mm, the thickness of the layer having the energy absorber properties being at least 0.4 mm.

The adhesion of this layer to the glass sheet should be higher than about 2 daN. 5 cm ^-1 as measured by the adhesion test as described below. However, this adhesion force should not be too high, especially when a layer of AE of relatively small thickness close to the lower limit of suitably about 0.4 mm is used.

The layer having the properties of the energy absorber may comprise various additives which generally serve to facilitate its production by reactive casting or which may improve the lower values of its properties.

For example, the layer may comprise a catalyst, for example a tin-based catalyst such as tin dibutyldilaurate, tributyiltin oxide, stannous octoate, an organomercury catalyst, for example phenyl mercuric ester, an amine catalyst, for example diazabicyclo [2,2,2] octane, 1,8- diazabicyclo [5.4.0] -1-decene-7.

As the stabilizer, the layer may comprise bis- (2,2,6,6-tetramethyl-4-piperidyl) sebacate, a phenolic antioxidant.

The layer may also contain a casting aid, such as a silicone resin, a fluoroalkyl ester, an acrylic resin.

For the production of a two-layer film, the following procedure can be performed:

First, a first layer is produced, which may be either a holding layer having energy absorber properties (layer AE) or an inner protective layer of a self-healing plastic (PI layer), consisting mainly of a heat-curable polyurethane. A second layer is then produced on this first layer.

Alternatively, a thermoset polyurethane layer may be produced by reactively casting a mixture of the individual components onto a casting carrier. After the polymerization of the monomers and the formation of a thermosetting layer having a thickness, which may be in the range of 0.1 to 0.8 mm, a reaction mixture of the layer constituents having energy absorber properties is poured onto it.

In another variation, it is possible to proceed in the opposite way, i.e. to first create a layer having energy absorber properties (layer AE).

To produce a laminated glass sheet comprising a film of one or two layers according to the invention, the individual components thereof are joined together by applying pressure, for example by pressing between two rollers of a calender.

Subsequently, the bonding between the individual components can be improved by heating the laminated glass sheet in an autoclave, for example, for one hour at a temperature of about 100 to 140 ° C at a pressure of about 1 to 5 bar, or by heating in an oven without pressure.

The production method of the film according to the invention and of the laminated glass panes containing it is described in more detail in the examples below.

Example 1

A homogeneous mixture containing the following proportions of the individual components is continuously poured onto a glass, continuously entrained carrier, provided with a release agent, which may be, for example, the agent described in French Patent Specification No. 2,383,000, namely an ethylene oxide modified adduct.

1000 g of a polyether having a molecular weight of approximately 450 obtained by condensation

1,2-propylene oxide with 2,2-bis (hydroxymethyl) -1-butanol and having a free hydroxyl group content of about 10.5-12%, containing a 1% w / w stabilizer, di-butyl tin dilaurate as a catalyst by weight an amount of 0.05% and a casting aid in an amount of 0.1% w / w; 1020 g of a 1,6-hexanediisocyanate biuret having a free isolyanate group content of about 23.2%.

A casting head, such as that described in French Patent No. 2,347,170, is used for casting. A uniform layer is formed which, after being polymerized by heat treatment, for example for about 15 minutes at 120 ° C, has a thickness of about 0 19 mm and self-healing capacity.

To produce a layer having energy absorber properties, a polyol component is prepared beforehand by mixing polytetramethylene glycol of molecular weight 1000 (for example, the product manufactured under the designation Polymeg 1000 by QUAKER OATS) with 1,4-butanediol, the relative amounts of both being such that 37 equivalents of hydroxyl groups, while 1,4-butanediol delivers 0.63 equivalents.

To the polyol component is added a stabilizer in an amount of 0.5% by weight, a casting aid in an amount of 0.05% by weight, and dibutyltin dilaurate as a catalyst in an amount of 0.02% by weight, based on the total weight of polyol component and isocyanate component. .

The isocyanate component used is 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), introducing urea groups released by partial hydrolysis of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate and having an NCO content of about 31.5% by weight. .

Said components are used in such amounts that the NCO / OH ratio is 1.

After degassing the components under reduced pressure, the mixture, heated to a temperature of about 40 ° C, is poured by means of a casting head, as described, for example, in French Patent Specification 2,347,170, onto a previously formed self-sealing polyurethane layer. This produces a layer of about 0.53 mm thickness, which is polymerized by exposure to 120 ° C for about 25 minutes.

The resulting two-layer film is peeled from a glass carrier; it can be easily handled, stored or used immediately after peeling off the carrier to produce the laminated glass panes of the invention.

To produce a laminated glass sheet, the two-layer film obtained above is bonded to a cooled glass sheet of 2.6 mm thickness. Optionally, the glass may be hardened or tempered. The joining of the glass sheet to the two-layer foil can be carried out in two stages, the first of which consists in the pre-bonding achieved by passing both parts of the laminated glass sheet between two rollers of the cailander; for this purpose, for example, the apparatus described in European Patent Specification <0 015 209 may be used, wherein the AE layer is applied to the inside of the glass sheet.

The second step consists in placing the resulting layered product in an autoclave and heating it at a temperature of about 135 ° C at a pressure of 10 bar for about 1 hour. The heating in the autoclave can optionally be replaced by heating in an oven without pressure.

The resulting laminated glass sheet exhibits excellent optical quality and perfect transparency.

The achieved adhesion of the layer having the energy absorber properties to the glass pane is determined on the finished product by the adhesion test described below:

A 5 cm wide strip is cut in the two-layer cover sheet. The end of the strip is torn off and is applied by pulling perpendicular to the surface of the glass sheet, the peeling speed being 5 cm. min “ ¹ . This is done at 20 ° C. The average tensile force required to peel the belt, in this case 10 daN, shall be determined. 5 cm ^-1 .

The impact resistance test is carried out on a laminated glass sheet produced according to this example.

The first impact resistance test is performed using a 2.260 kg steel ball (large ball test) which is dropped onto the specimen of a 30.5 cm side laminate glass sheet embedded in a rigid frame. The approximate height at which a falling ball at a given temperature does not break through the test sample at 90% of the test samples shall be determined.

In the laminated glass sheet according to this example, this height is 8 meters.

Another impact resistance test is performed using a steel ball with a diameter of 38 mm and a weight of 0.227 kg. It is performed twice, once at a temperature of -20 ° C, and a second time at + 40 ° C. The readings are 11 and 13 meters.

According to the current European standard R 43, these values should be at least 4 meters when using a large ball, at least 8/5 meters when using a small ball at -20 ° C and at least 9 meters when using a small ball at +40 ° C.

As regards the other properties, the PI layer exhibits surface properties satisfactory when used in a laminated-glass pane, and in particular scratch and abrasion resistance, determined as follows:

The scratch resistance is determined by a known test, referred to as the "MAR test". This test is carried out using an Erichsen type 413 apparatus. The load to be loaded by the diamond-provided head of the apparatus is determined to produce a permanent groove on the plastic layer deposited on the glass carrier. The load should be at least 20 g so that the plastic layer is self-sealing.

The abrasion resistance shall be determined in accordance with European standard R 43. After 100 revolutions, the matt difference of the unground and abraded parts is determined spectrophotometrically. This difference i (matte A) should be less than 4% to make the layer abrasion resistant.

The laminated glass sheet of this example has all the characteristics that make it suitable for use as a vehicle windshield.

Check example

The same procedure was carried out as in Example 1, using the same starting materials in the same proportional amounts for the production of the AE layer, except that this layer was not made by reactive casting but by several individual pouring of solution in polyurethane prepared in solution to form a layer of 0. , 53 mm.

The adhesion test gives a value of 8 daN. 5 cm ¹ .

Impact resistance tests carried out under the same conditions as in Example 1 show the following values:

- 3.5 meters using a large ball, 4 meters, respectively. 3 meters when using a small ball at a temperature of -20 ° C resp. + 40 ° C.

These values are insufficient, indicating that by successive casting of the finished resin solution, a suitable layer is not obtained, unlike Example 1, where the reactive casting AE layer exhibits satisfactory values of the desired properties.

Example 2

The procedure is as in Example 1, except that layers of different thicknesses are produced, i.e. a self-sealing layer (PI layer) of 0.41 mm thickness and an AE layer of 0.29 mm thickness.

The laminated glass sheet produced has the following characteristics:

The adhesion test reveals a tensile force of 10 daN. 5 cm ⁴ . The values determined by the large-ball test and the small-ball test are 3.5, respectively. 9 and 9 meters, which are insufficient values due to insufficient layer thickness having energy absorber properties.

Example 3

The procedure is as in Example 1, except that a PI layer of 0.315 mm thickness and an AE layer of 0.415 mm thickness are produced.

The adhesion test reveals a tensile force of 10 daN. 5 cm ^-1 . The values determined by the tests using a large ball and a small ball are 4.5, respectively. 10 and 13 meters, which is quite convenient.

Example 4

The procedure is as in Example 1, except that a PI layer of 0.32 mm thickness and an AE layer of 0.42 mm thickness are produced and that the glass surface is subjected to a classical adhesive method, such as silanes, for example, to achieve higher adhesion.

The tensile strength of 20 daN is determined by the adhesion test. 5 cm * ¹ .

The value determined by the large ball test is 3.5 meters.

The cause of this lack of impact resistance is the excessive adhesion of the AE layer to the glass sheet when the layer has a relatively low thickness. Although the thickness of the layer is the same as in Example 3, a laminated glass sheet is obtained in Example 3 with a satisfactory property due to the lower contact force.

Example 5

The procedure is as in Example 1, except that a 0.46 mm thick PI layer and a 0.56 mm thick AE layer are produced and that the glass surface is treated as in Example 4 before assembling the laminated glass sheet.

The tensile strength of 20 daN is determined by the adhesion test. 5 cm * ¹ . The values determined by testing 261870 kami using a large and a small ball are 8, respectively. 11.5 and 13 meters.

Comparing this example to Example 4, it appears that, despite high adhesion, the use of an AE layer of greater thickness provides satisfactory impact resistance values.

Example 6

The procedure is as in Example 1, except that the polyol starting compound for forming the AE layer is prepared from a mixture of polyether tetramethylene glycol having a molecular weight of 1,000, with 1,4-butanediol and polycaprolactontriol (e.g. procdut produced under the designation Niax 301 by UNION CARBIDE). which are used in proportional amounts such that 0.35, 0.55 and 0.10 equivalents of each of the above polyols are used per 1 equivalent of hydroxyl groups.

A PI of 0Д60 mm and an AE of 0.660 mm are formed.

The obtained laminated glass sheet is characterized by completely satisfactory optical and mechanical properties. The values measured in the individual tests are as follows: adhesion 3 daN. 5 cm ^-1 , impact resistance using a large ball of 9 meters, using a small ball of 13 and 13 meters.

Example 7

The procedure is as in Example 6, except that the relative amounts of the individual polyols are 0.35 equivalents of OH for the polymer of 1000, 0.45 equivalents of OH for the 1,4-butanediol and 0.20 equivalents of OH for the Niax 301.

A PI layer 0.31 mm thick and an AE: g layer 0.48 mm thick are formed.

The values measured in each test are: adhesion 3 daN. 5 cm ^-1 , impact resistance using a large ball of 4.5, using a small ball of 10 and 12 meters, which are satisfactory values.

Example 8

The procedure is as in Example 7 except that a PI layer of 0.39 mm thickness and an AE layer of 0.39 mm thickness are also formed.

The values measured in the individual tests are as follows: adhesion 4 daN. 5 cm ^-1 , impact resistance using a large ball 3, using a small ball 8, resp. 8 meters. These values are insufficient.

A comparison of these results with those of Example 7 shows that, with the same two-layer film thickness, the ratio of the layer thickness AE to the layer thickness JH is decisive for obtaining a satisfactory laminated glass sheet.

The following examples relate to a variation of the film of the invention consisting of a single layer and laminated glass sheets containing the film.

Example 9

To produce a layer of pilastic mass, a polyol component is prepared in advance by mixing polytetramethylene glycol having a molecular weight of 1,000 (for example, the product manufactured under the designation Polymeg 1000 by QUAKER OATS) with 1,4-butanediol, using proportional amounts of both components to introduce polytetramethylene glycol. 0.37 equivalents of hydroxyl groups, while 1,4-butanediol delivers 0.63 equivalents.

0.5% w / w stabilizer, 0.05% w / w casting aid and 0/12% w / w dibutyltin catalyst were added to the poilyol component, all based on the total weight of the poilyol component and isocyanate components.

The isocyanate component used is 3-isocyanatomethyl-3,5,5-trimethylcyclohexyildiisocyanate (IPDI), yielding urea groups, released by partial hydrolysis of 3-isocyanatomethyl-3,5,5-trimethylcycilohexyl diisocyanate, and having an NCO content of about 31.5 ° C. /O.

Said components are used in such proportional amounts that the NCO / OH ratio is 1. After degassing the components under reduced pressure, the mixture heated to 40 ° C is poured by means of a casting head, as described, for example, in French patent no. 2,347,170, onto a continuously carried glass carrier coated with a release agent. This creates a layer of uniform thickness of approximately 0.755 ^; which is polymerized by exposure to 120 ° C for approximately 2-5 minutes.

After polymerization, the layer is peeled from a glass carrier to form a film which can be stored or used immediately after formation to produce laminated glass panes.

To produce the laminated glass sheet, the plastic sheet is joined to a cooled glass sheet of 2.6 mm thickness. Optionally, the glass may be tempered or tempered. This assembly can be carried out in two stages as described in Example 1.

The obtained laminated glass sheet is characterized by excellent optical quality and perfect transparency.

The adhesion of the polyurethane layer to the glass sheet is 10 daN. 5 cm ⁴ .

Impact resistance (impact strength) tests at various temperatures are performed with the laminated glass sheet produced according to this example.

When using a large ball at +20, a value of 12 meters is measured, when using a small ball at a temperature of -20 ° C 12 meters and a temperature of +40 ° C 11 meters.

The scratch resistance of the laminated glass sheet produced according to this example, determined by the test described in Example 1, is 32 g.

The abrasion resistance of the layer according to this example, expressed as the abrasion matt difference, is 0.94%.

Example 10

The procedure is as in Example 8, except that the polyol layer is made from a mixture of 1000 molecular weight polytetramethylene glycide with 1,4-butanediol and polycaprolactontricil (for example, the product manufactured under the designation Niax 301 by UNION CARBIDE) used in in relative proportions such that, from one total equivalent of hydroxyl groups, each of the aforementioned compounds delivers 0.35, 0.45 and 0.20 equivalents.

A layer of 0.70 mm thickness is produced. The laminated glass sheet produced has very good mechanical and optical properties. The results of the individual tests are as follows:

- adhesion 11 daN. 5 cm ^-1 , impact resistance when using a large ball 8 meters, when using a small ball at a temperature of both —20 ° C, also +40 ° C 11 meters, - scratch resistance 35 g and abrasion 1.2%.

Example 11

The procedure is as in Example 9, except that relative amounts of the individual starting materials are used to produce the polyol component such that from 1 equivalent of the polyol component, 0.35 equivalents per long polyol, 0.55 equivalents per short diol, and 0, 10 equivalents per triol.

A 0.66 mm thick layer is formed. The values obtained by measurement for each test are those obtained by measurement for each test:

- adhesion 11 daN. ¹ 5 cm, impact resistance when using large balls 10 m when using small balls 13.5 meters at both -20 ^Q C and +40 ° C, scratch resistance, abrasion resistance 25 g of 1.2%.

Although the film according to the invention has been described primarily with regard to its use for the production of laminated glass panes, it can advantageously be used in other cases, either alone or associated with other transparent or opaque materials.

Example 12

The procedure was as in Example 1, except that the polymerization of the layer was carried out at a temperature of only 60 ° C for 20 hours. The results of the impact resistance tests carried out under the same conditions as in Example 1 are as follows:

- 6 meters using a large ball, 6 meters and 13, 5 meters using a small ball at a temperature of -20 ° C, respectively. + 40 ° C.

The value obtained when using a small ball at a temperature of - 20 ^q C is insufficient.

This example, compared to Example 1, illustrates the effect of the higher poly-polymerization temperature at which reactive casting is performed. The temperature used in this example is too low.

Claims (11)

CLAIMS 1. A method for producing a transparent plastic film of high optical quality, comprising a polyurethane-based layer having energy absorber properties, characterized in that the layer having energy absorber properties is produced by reactively casting a reaction mixture of an isocyanate component having a viscosity of less than 5 Pa. . at +40 ° C with a polyol component on a horizontal flat support, wherein the isocyanate component comprises at least one aliphatic or cycloaliphatic diisocyanate or isocyanate pre-polymer and the polyol component comprises at least one long difunctional polyol having a molecular weight of 500-4000 and at least one short diol and the ratio of the number of equivalent isocyanate groups to the number of equivalent hydroxyl groups is in the range of 0.9 to 1.1, and the relative amounts of the individual polyols are selected such that the number of equivalent hydroxyl groups introduced by the short diioil is 20 to 70% of % of the total number of hydroxyl groups, after which the layer is polymerized on a horizontal flat support. 2. Process according to claim 1, characterized in that an isocyanate component containing urea groups is used, the proportion of urea being up to 10% by weight of the total amount of the isocyanate component, and preferably in the range of 5 to 7%. 3. A process according to claim 1, wherein the isocyanate component is 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate. 4. A process according to any one of claims 1 to 3, wherein the isocyanate component comprises 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate containing urea groups and the polyol component is composed of polytetramethylene glycol having a molecular weight of about 1,000 and 1. 4-butanediol. 5. A method according to any one of claims 1 to 4, characterized in that a polyol component comprising at least one polyol having a functionality greater than 2 is used. 19 20 6. A process according to claim 5, wherein the polyol having a functionality greater than 2 is triol. 7. A method according to any one of claims 1 to 6, wherein a polyol component is used, wherein from one equivalent of all its hydroxyl groups the long polyol is 0.30 to 0.45 equivalents, the short diol is 0.2 to 0. 7 equivalents and a polyol having a functionality greater than 20 to 0.35 equivalents. 8. A process according to any one of claims 1 to 7, wherein additives such as a catalyst, a casting aid and a stabilizer are added to the reaction mixture to form a polyurethane layer having energy-absorbing properties. Process according to Claims 1 to 8, characterized in that the polymerization following the reactive casting is carried out at a temperature higher than 80 ° C, preferably 80 to 140 ° C. 10. The process of claims 1 to 9, wherein at least one triisocyanate is added to the isocyanate component. 11. A method according to any one of claims 1 to 10, characterized in that the reactive casting is carried out on a horizontal flat support on which a self-stable thermosetting polyurethane layer has previously been formed.