FR2654672A1 - Application of composite polyester release films as support for the formation of at least one layer of polyurethane which can be employed in safety glazing - Google Patents

Abstract

Application of a polyester release film as support for the formation of sheets of plastic material comprising at least one layer of polyurethane of good optical quality by applying at least one liquid mass over the said mobile, stretched, horizontal, planar support. In the application according to the invention the polyester release film consists of a base film made of semicrystalline oriented polyester (A) comprising on at least one of its faces a coating consisting of a) a fluorinated polymer and b) an effective quantity of a water-dispersible polyester derived from at least one aromatic dicarboxylic acid and from at least one diol and comprising a plurality of sulphonyloxy groups of general formula: (I) (SO3)nM in which: - n is equal to 1 or 2, - M denotes a hydrogen atom, an alkali or alkaline-earth metal, an ammonium cation or a quaternary ammonium cation. l

Description

 The present invention relates to the application of new antiadhesive composite polyester films as temporary supports for the manufacture of polymer films and in particular for the manufacture of at least one polyurethane layer of high optical quality, suitable for use in a glazing unit of security.

 It is known that sheets or films of plastic material meeting particular requirements as to their physical properties (scratch resistance, transparency, surface condition, self-healing ability of scratches, tear resistance in particular) are used for the manufacture so-called asymmetric laminated glazing comprising a monolithic or laminated support glass and / or plastic, and said plastic sheet. These glazings can be used as building glazing, as glazing for motor vehicles, as glasses of safety glasses, etc ... Thus, in the French patents 2 187 719, 2 251 608 and European 0 132 For example, it has been proposed to place on the glass sheet intended to be oriented towards the inside of the passenger compartment of the vehicle, a layer of a crosslinked elastic polyurethane (thermosetting) having excellent properties of antilacération and self-healing, that is, possessing the ability to remove accidental scratches. The polyurethane layer may be used alone or in combination with another layer having adhesive and / or energy absorber properties, in particular a thermoplastic polyurethane layer or a polyurethane layer obtained by reactive casting or reactive sputtering a mixture of reaction components as described in European Patent Publication 0 132 198 already cited.

 These polyurethane layers must have good optical quality and in particular must be free from surface defects. By good optical quality is meant according to the invention the optical quality necessary for the use of these layers in a transport vehicle glazing. It has already been proposed to manufacture these layers by casting the liquid mass comprising the precursors of the polyurethane, on a stretched flexible support, made of plastic, delivered continuously from coils as and when casting. When the thermosetting polyurethane layer is formed it can be immediately separated from the temporary plastic carrier or, preferably, it can be wound with said carrier which then plays a protective film groove until its final use.

 When the polyurethane sheet comprises a thermosetting layer and a layer having adhesion and / or energy absorber properties (hereinafter referred to as the AE layer description), the precursors of these layers are successively cast in an order indifferent, so that the temporary support may be in contact with either the AE layer or with the thermosetting layer.

 The plastic forming the temporary support must meet various requirements relating to its surface state, its chemical inertness vis-à-vis the polyurethane precursors, its elasticity, its windability and its ability to separate easily from the polyurethane sheet under the effect of traction, while maintaining good adhesion in the absence of traction. Polyester films which fulfill a number of these requirements have been proposed as temporary supports for polyurethane sheets, composite or otherwise, for example in French patent publications 2 480 669 and 2 546 810. However, the polyester films do not realize a excellent compromise between sufficient adhesion to the polyurethane sheet and easy separability under the effect of traction exerted on the support film.La plaintiff has therefore proposed as a goal the use of a new polyester film composite as a temporary support for polyurethane sheets that can be separated easily under the effect of traction, without damage to the surface of the polyurethane film, that is to say without tearing of this surface and / or without deposit on this surface of material torn from the temporary support film.

More specifically, the subject of the present invention is the use, as a formation medium, of a polyurethane layer of high optical quality suitable for use in the manufacture of safety glazings, a non-adherent composite polyester film, this film being consisting of a semi-crystalline oriented polyester backing film (A) having on at least one side thereof a coating consisting of a) a fluoropolymer and b) an effective amount of a dispersible polyester in the water derived from minus one aromatic dicarboxylic acid and at least one diol and having a plurality of sulfonyloxy groups of the general formula
(I) (SO3) = M in which
n is 1 or 2
M represents a hydrogen atom, an alkaline or alkaline-earth metal, an ammonium cation or a quaternary ammonium cation.

 For the purposes of the present invention, the term "water-dispersible polyester" means water-soluble polyesters or polyesters which form stable dispersions in water.

 The polyesters used to obtain the support (A) of the composite films used according to the invention are those which are usually used to obtain bi-oriented semi-crystalline films. These are linear film-forming polyesters, crystallizable by orientation and obtained in the usual manner from one or more aromatic dicarboxylic acids or their derivatives (esters of lower aliphatic alcohols, halides, for example) and from one or more aliphatic glycols. . Examples of aromatic diacids are phthalic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic-2,5; These acids may be associated with a minor amount of one or more aliphatic dicarboxylic acids such as adipic, azelaic, hexahydro terephthalic acids. Non-limiting examples of aliphatic diols include ethylene glycol; 1,3-propanediol; butanediol-1,4. These diols may be associated with a minor amount of one or more aliphatic diols more condensed in carbon (neopentyl glycol for example) or cycloaliphatic (cyclohexanedimethanol).

Preferably, the crystallizable film-forming polyesters are polytere phthalates or polynaphthalenedicarboxylates of alkylenediols and, in particular, polyethylene terephthalate (PET) or 1,4-butanediol or copolyesters comprising at least 80 mol% of terephthalate units or naphthalenedicarboxylates of alkylene glycols. Advantageously, the polyester is an ethylene glycol polyterephthalate whose intrinsic viscosity measured at 250C in o-chlorophenol is between 0.6 and 0.75 dl / g.

 The polyester support films (A) may themselves be simple or composite. Thus, it is possible to use a coextruded polyester film, one layer of which is loaded to communicate to said layer a roughness sufficient to ensure the machinability of the assembly and of which the other layer is unloaded or comprises fillers whose particle size is chosen for do not cause surface defects in the release coating. It is also possible to use composite polyester films consisting of a semicrystalline oriented polyester film comprising on at least one of its faces a primary coating of adhesion deposited by coating or by co-extrusion such as those described in the European Patent Applications Nos. 267,856,275,801; 260,203; 272,993.

 The fillers present in the support polyester films (A) may have been introduced during the polycondensation or in the polymer by the usual processes or they may result from the precipitation of catalytic residues under the influence of additives introduced during the polycondensation. . The nature of these charges is not critical; they may be inorganic compounds (oxides or salts of elements of groups II, III and IV of the Periodic Table).

 By way of illustration, mention may be made of silicas, silico aluminates, calcium carbonate, titanium oxide, magnesium oxide, alumina, barium sulphate, polystyrene preferably crosslinked by divinylbenzene, polymers thermotropes (polyester in particular).

 The amount of filler and the mean diameter of the particles are chosen so as to give the polyester support film surface properties (roughness and coefficients of friction) sufficient to ensure good machinability, without causing the appearance of surface defects. on the adhesive coating (B) by transfer effect.

 In general, the average particle diameter is less than 3 m; it is preferably between 0.02 and 2 Wm. The amount of filler is less than or equal to 1% by weight of the polyester and is preferably in a range of 0.01 to 0.1%.

The antiblocking layer (B) is obtained by depositing on at least one of the faces of the support film (A) an aqueous composition, emulsion or suspension, essentially comprising
a) a fluoropolymer
b) a dispersible polyester in water with sulfonyloxy groups.

 The fluorinated polymers which are suitable for the implementation of the invention may be in particular the polymers and copolymers of vinylidene fluoride, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene with each other or with nonfluorinated monomers (ethylene for example). polyvinylidene fluoride (PVDF) is particularly suitable. These fluorinated polymers may be used in the form of powders or in the form of aqueous emulsions or dispersions, for example such as those obtained by emulsion or suspension polymerization of the monomer or monomers. The solids content of the emulsions or dispersions of fluoropolymer is not critical.

 The water-dispersible sulfonyloxy polyesters associated with the fluoropolymer are known products. A first group of dispersible polyesters in the bed are those described in particular in French Patent Nos. 1,401,581 and 1,602,002 and European Patent Application No. 129,674; For the purpose of the present invention, it is possible to use the sulfonyloxy-containing polyesters described in these patents. More specifically, the water-soluble or water-dispersible polyesters are obtained by polycondensation of one or more aliphatic dicarboxylic diols with at least one or a plurality of aliphatic diols and at least one difunctional compound having at least one sulfonyloxy group; later, for the sake of convenience, the term "sulfonyloxy group" will refer to both the hydroxysulfonyl groups and the alkali, alkaline earth or ammonium salts derived therefrom.

 Among the aromatic dicarboxylic acids which can be used for preparing the water-dissipatable polyesters, mention may be made, by way of non-limiting examples: terephthalic, isophthalic, phthalic, 1,4-naphthalenedicarboxylic acid, 4,4'-oxibenzoic acid, bis ( 4-hydroxycarbonylphenyl) sulfone, 4,4-dihydroxycarbonylbenzophenone. These acids can be used alone or in mixtures. Among the above acids, terephthalic and isophthalic acids are preferably used alone or in combination with the other acids mentioned. Mixtures of terephthalic acid with one or more other aromatic dicarboxylic acids and in particular with isophthalic acid are particularly suitable for obtaining sulfonated polyesters which can be dispersed in water. In this case, the amount of terephthalic acid expressed in moles can vary between 20 and 99% of the total number of moles of unsulfonated diacids and preferably between 30 and 95%.

 For the preparation of the dissipable copolyesters of aliphatic dicarboxylic acids having from 3 to 15 carbon atoms may be associated with aromatic diacids. More particularly all or part of the aromatic acid used in conjunction with terephthalic acid (for example isophthalic acid) can be replaced by aliphatic acids such as adipic, suberic, sebacic, succinic, dodecanedioic acid.

 For the preparation of the sulfonated polyesters dispersible in water, the dicarboxylic acids can be replaced, during the polycondensation, by their derivatives usually used in this type of anhydrides, esters or acid chlorides reaction. Esters, and in particular methyl esters, are preferably used.

 As examples of diols that can be used for the preparation of sulphonated polyesters that can be dispersed in water, mention may be made of ethylene glycol; butanediol-1,4-butanediol-1,3. 1,3-propanediol; 1,2-propanediol, 2,2-dimethyl-1,3-propanediol; pentanediol-1,5-hexanediol-1,6; diethylene glycol; triethylene glycol; neopentyl glycol; cyclohexanedimethanol; tetraethylene glycol; penta-, hexa- or decamethyleneglycol. Ethylene glycol and its oligomers are particularly suitable for the preparation of sulfonated polyesters. They can be used alone or mixed with each other and / or with other diols. Mixtures of ethylene glycol and its oligomers of formula HO- (CH> -CH2-O) = H wherein n is an integer of 2 to 10 are preferred.

 The sulphonyloxy groups of formula -SO 3 M are introduced into the polyester via a difunctional compound having a sulphonyloxy group capable of reacting with the diacids and / or the diols during the polycondensation. Examples of such monomers are cited in French Patent No. 1,602,002. Alkali metal salts of sulfonyloxy aromatic dicarboxylic acids such as those of sulfoterephthalic, sulphoisophthalic, sulphophthalic and hydroxysulphonyl-4 acids are preferably used. 2,7-naphthalenedicarboxylic acid or derivatives thereof and in particular their esters.

 The amount of sulfonyloxy bifunctional compound present in the sulfonated polyester, expressed in moles for a total of 100 moles of difunctional compounds of the same kind, is preferably in the range of 2 moles to 30 mole%. In general, amounts of sulfonated difunctional compounds of between 5 moles and 15 moles for a total of 100 moles of difunctional compounds of the same type are suitable. Thus, when an alkali metal salt of 5-hydroxysulfonylisophthalic acid is used, this compound may represent from 2 moles to 30 moles for a total of 100 moles of dicarboxylic acid units present in the polyester.

 The water-dispersible polyesters described above are obtained by the usual methods, for example by reaction of the diol (s) with a mixture of the necessary methyl esters of various acids, in the presence of the usual transesterification catalysts, and then polycondensation of the diol esters as well as obtained. The amounts of each of the reactants are calculated so that the ratio of the total number of alcoholic hydroxyl groups to the total number of carboxylic groups is preferably between 2 and 2.5.

 A second group of water-dispersible polyesters containing sulphonyloxy groups is constituted by polyesters such as those described previously modified by grafting at least one monomer of acrylic nature and optionally at least one other monomer containing ethylenic unsaturation. Such modified polyesters and their method of production have been described in European Patent Application 0 260 203.

dans laquelle
- R représente un atome d'hydrogène ou un groupe alkyle inférieur, éventuellement substitué par un groupe hydroxyle
- Y représente un groupe fonctionnel hydroxycarbonyle alkoxycarbonyle de formule -COORl dans lequel R1 est un radical alkyle comportant de 1 à 20 atomes de carbone, linéaire ou ramifié (éventuellement substitué par un reste hydroxyle); nitrile ; amide de formule -CON(R2,R3) dans laquelle R2 et R3, identiques ou différents représentent un atome d'hydrogène ou un reste alkyle linéaire ou ramifié, comportant de 1 à 20 atomes de carbone.The acrylic monomers used for the preparation of the modified polymers can be represented by the general formula

in which
R represents a hydrogen atom or a lower alkyl group, optionally substituted with a hydroxyl group;
Y represents a hydroxycarbonyl alkoxycarbonyl functional group of formula -COOR1 in which R1 is an alkyl radical containing from 1 to 20 carbon atoms, linear or branched (optionally substituted with a hydroxyl radical); nitrile; amide of formula -CON (R2, R3) in which R2 and R3, which may be identical or different, represent a hydrogen atom or a linear or branched alkyl radical containing from 1 to 20 carbon atoms.

 By lower alkyl radical is meant alkyl radicals having from 1 to 4 carbon atoms.

 As specific examples of radicals R 1, R 2 and R 3, mention may be made of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, decyl and dodecyl radicals. , octadecyls.

Examples of hydroxyalkyl radicals R1 include hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl radicals.

 In the formula (II), R preferably represents a hydrogen atom or methyl or hydroxymethyl radicals.

Among the acrylic derivatives of formula (I) which can be used for the preparation of the modified polymers, non-limiting mention may be made of: acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide,
N-methylacrylamide, acrylates and methacrylates of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, stearyl. These monomers can be used alone or in mixtures of two or more acrylic derivatives. As an example of a combination of acrylic derivatives, mention may be made of the following mixtures: methyl methacrylate / acrylic acid and / or methacrylic acid, methyl methacrylate / acrylic acid or methacrylic / ethyl acrylate; methyl methacrylate / ethyl acrylate / acrylamide or methacrylamide; acrylamide / methacrylamide; butyl acrylate / acrylic acid butyl methacrylate / ethyl acrylate.

 The acrylic compounds may also be associated with a minor amount of one or more ethylenic monomers such as vinyl acetate, vinylidene chloride, styrene, methylstyrene, crotonic, itaconic, fumaric or maleic acids, alkaline salts or alkaline earths of ethylenic sulfonic acids such as vinylsulfonic, allylsulfonic, methallylsulfonic, styrene-sulfonic acids. The amount of non-acrylic ethylenic monomer is calculated so that in the copolymer obtained the number of repeating units of this non-acrylic monomer expressed in moles per 100 moles of acrylic monomer is preferably less than or equal to 20% and even more preferably at 10%. Quantities of ethylenic units representing from 0.1 to 5 mol% are suitable.

 It is possible, within the scope of the present invention, to associate with these monomers one or more monomers capable of causing a crosslinking of the acrylic part. For this purpose, it is possible to use polyethylenic monomers capable of crosslinking under the action of the free radical generators during the polymerization or else to monomers causing a crosslinking of the acrylic part by heating, for example during the process. of obtaining the coated film or during a subsequent thermal treatment of the coated film.

As an example of polyethylenic monomers, mention may be made of diallyl phthalate, divinylbenzene, diacrylates or dimethacrylates of diols such as ethylene glycol dimethacrylate. Hydroxyalkyl (meth) acrylamides, such as N-methylolacrylamide and N-methylol methacrylamide, are suitable as crosslinkers under the effect of heat.

 The amount of crosslinking monomer expressed as above is preferably less than 5 moles per 100 moles of non-crosslinking acrylic monomer. In general, it is between 0.1 and 3 mol%.

 For the preparation of the modified polymers, the usual techniques for the radical polymerization of ethylenically unsaturated monomers in the aqueous phase are carried out. In general, the polymerization is carried out by dispersing the acrylic monomer (s) in a suitable volume of water into which the necessary quantity of a dispersible sulfonated polyester and, if appropriate, one or more conventional emulsifying agents are introduced. that the sulfonated polyester can itself act as an emulsifier allowing the dispersion of the monomer (s) in the water, this does not exclude the use of the usual surfactants such as, for example, the alkaline salts of sulphates long chain alcohols (sodium lauryl sulphate; ethanolamine lauryl sulphate) alkali metal salts of long chain sulphonic acids nonionic emulsifiers such as polyoxyethylene glycols and their derivatives; alkoxylated alkylphenols, optionally sulphated. The polymerization is initiated with the aid of the usual free radical generators such as peroxide compounds: persulfates, hydrogen peroxide, organic peroxides (lauroyl peroxides, benzoyl, t-butyl hydroperoxide); azo compounds (azodiisobutyronitrile); redox systems combining a peroxidic compound, preferably water-soluble and a reducing agent: ferrous salts (sulphate), sulphites or alkaline bisulfites.

 Other customary adjuvants for polymerization may be present in the reaction medium. Thus, one can operate in the presence of a conventional chain limiting agent such as mercaptans (dodecylmercaptan, tetradecylmercaptan), so as to adjust the molecular weight of the copolymer obtained according to the properties desired for the coating.

 The temperature at which the polymerization is conducted can vary within wide limits. In general, a temperature between 10 and 1000C and preferably between 20 and 800C is suitable.

 The study of the product resulting from the polymerization of at least one acrylic monomer as defined above, in the presence of a dispersible polyester, has shown that the polyester is chemically bonded to the acrylic polymer. Without the invention being limited in any way to a particular reaction mechanism, it appears that the polyester and the acrylic monomer (s) react during the polymerization to form a graft copolymer.

 The concentration of the dispersible polyester and the polymerizable monomer (s) in the aqueous polymerization phase is not critical and may vary within wide limits. This concentration is chosen according to the solids content desired for the final emulsion and the rate of polymerization of the monomer (s) under the polymerization conditions.

 The aqueous product obtained after polymerization can be used directly to obtain the composite films according to the invention. It can also be subject to various treatments. Thus, it is possible at the end of the polymerization to remove the monomers which have not been converted by the usual means. When one or more of the reaction components comprises free acid functions, the latter can be neutralized by addition of a mineral or organic base; an alkaline base (sodium hydroxide, potassium hydroxide), a quaternary ammonium hydroxide or ammonia is preferably used. It may be the sulfonic acid functions of the dispersible polyester and / or the carboxylic acid functions of the (co) acrylic polymer. It is also possible to add adjuvants such as stabilizers or antistatic agents to the emulsion obtained. According to one variant, it is possible to introduce into the emulsion obtained known external crosslinking agents of the acrylic (co) polymers.

 The nature of the external crosslinking agents depends on the nature of the acrylic monomer (s). Among the preferred crosslinking agents, there may be mentioned formophenolic resins, amine-formaldehyde resins such as melamine / formaldehyde, urea / formaldehyde, triazine / formaldehyde condensation products. The amount of crosslinking agent is then generally between 0.1 and 15% by weight and preferably between 0.5 and 12% by weight relative to the total weight of the dispersible polyester and the acrylic (co) polymer present in the emulsion. .

 The product resulting from the polymerization has various forms, depending on the proportion and nature of the reagents involved and / or the conditions of the polymerization, and / or the final treatment applied to the product obtained. Thus, the products resulting from the polymerization of a non-acidic acrylic monomer with a significant amount of a polymerizable acid ((meth) acrylic acid, crotonic acid), for example at least 5 mol% of the total polymerizable monomers can be present in the form of a true emulsion when the carboxylic acid groups are free or in the form of more or less viscous aqueous solutions when the carboxylic groups are neutralized by means of one of the abovementioned bases and in particular by means of an alkaline base .

The viscosity of the dispersions or solutions of modified polymers is not critical and can be adjusted at will as needed by changing their solids content.

 The aqueous coating composition can be obtained by dispersing a suitable amount of a fluoropolymer in an adequate amount of an aqueous solution or dispersion of dispersible polyester, whether or not modified, or by mixing suitable amounts of an emulsion or dispersion. aqueous fluoropolymer and an emulsion or dispersible aqueous polymer dispersion. The dry weight content of the aqueous coating composition is not critical and may vary within wide limits. For practical reasons it is better that. the solids content of the coating composition is between 5% and 35% by weight.

 The weight content of the dispersible polyester coating composition, whether modified or not, expressed with respect to the fluoropolymer, is calculated to give the composite film physico-chemical surface properties which make it suitable for use as a temporary support for films or sheets. plastics and especially thermoplastic or crosslinked polyurethane films or sheets. Ultimately this content is chosen to ensure both sufficient adhesion to these sheets or films in the absence of any traction and easy separation under moderate traction. This so-called effective content depends to some extent on the surface physicochemical properties of the films or sheets to be supported. It is also calculated to ensure the coating a smooth surface.In fact, it has been found that the presence of an adequate amount of dispersible polyester allows to obtain a film free of trees that develop on the surface of the coating of fluoropolymer in the absence of dispersible polyester.

 In general, the amount of dispersible polyester that may or may not be modified represents from 5% to 50% by weight of the fluoropolymer and preferably from 10% to 45% by weight.

 In addition to the fluoropolymer and the dispersible polyester, the coating composition may contain any additive necessary for its chemical and / or physical stability; thus it may contain antioxidants, anti-W, ionic or nonionic surfactants.

 Deposition of the coating on the polyester support film can be achieved by the various techniques known to those skilled in the art. Thus, the aqueous polymer composition can be deposited by gravity from a slotted cast, or by passing the film through the composition or by means of transfer rollers. The thickness of the layer is controlled by any appropriate means.

The deposition of the coating may take place either before any stretching of the film (in-line coating) or after stretching before or after heat-setting (coating in recovery). However, it is preferred to coat the polyester film before drawing or between two draws.

 Prior to the coating, the polyester film may be subjected to a surface treatment chosen from those usually used and, more particularly, from the physical treatments. Thus, the face intended to receive the coating may be subjected to electric discharges (corona treatment) or to ionizing radiation.

However, such treatments are not essential.

 The amount of aqueous coating composition deposited on the film depends, on the one hand, of its dry extract content and, on the other hand, of the desired thickness for the coating of the finished film, that is to say after stretching and heat setting when coating takes place online. This quantity also depends on the time of the coating; it is obviously necessary to take into account the thickness variation of the coating before and after stretching, when the coating is carried out before stretching. The thickness of the finished coating can vary within wide limits.

 In general, a thickness of the polymer coating of from 0.05 μm to 0.5 μm is suitable. Preferably, it is in a range of 0.1 to 0.3 Wm. The amount of dry extract deposited on the polyester film to obtain such thicknesses is between 0.04 and 0.4 g / m2.

 After coating, the polyester film is heat treated to remove the water contained in the coating and, where appropriate, to cause the crosslinking of the dispersible polyester. In the case of the coating in line, it is not generally necessary to carry out a heat treatment; drying and optionally crosslinking are carried out during drawing and heat setting. However, it would not be outside the scope of the present invention, in this case, prior to stretching and heat-setting, to heat treatment sufficient to cause coalescence of the latex and drying.

 The polymer coating may be applied to only one or both sides of the polyester support film.

 In order to manufacture the polyurethane layer or layers on the polyester support film according to the invention, it must be stretched longitudinally and laterally to form a horizontal plane support.

 For this purpose, it is advantageous to use the means of the device described in the European patent publications 0 038 760 or 0 131 483 already mentioned.

 The device used comprises a distributor of the polyester film, means exerting on this tape tensile forces longitudinally and transversely so as to stretch it and make it as perfectly plane and horizontal as possible, means for driving the ribbon in a movement of continuous feed, means for depositing in at least one place the liquid mass, capable of forming the polyurethane layer on the ribbon, heating means for solidifying the liquid mass by polymerization of the components and / or evaporation of the volatile products, means horizontally supporting the ribbon over its useful width, at least at the location where the liquid mass is brought.

 According to one embodiment of the device, the means exerting traction forces on the polyester support film are essentially a tractor roller located at the end of the line, associated with at least one resistive roller located in the upstream part of the line, and roulettes called casters edges, which on both sides of the polyester film, above and below said polyester film, exert on it lateral component forces to the outside. The casters can have an adjustable action; their angle of inclination with respect to the direction of advance of the polyester film may vary, as well as their pinch forces.

 Alternatively, the polyester support film may be stretched laterally by clamps that move simultaneously and parallel with the ribbon.

 At the end of the casting line, means allow the winding of the formed sheet.

 In one embodiment of the device, the means horizontally supporting the polyester film over its useful width, that is to say the width covered by the liquid mass at least at the locations where the liquid mass is provided, may be rolls arranged at the locations indicated under the polyester film, and if necessary, at other locations of the device forming the casting line.

 In a variant, the means horizontally supporting the polyester film of the casting (s) at locations and vents in other places, are advantageously metal or glass plates themselves supported by suitable members, for example rollers, or directly by a frame itself.

 This variant is advantageous because the plates can at the same time serve to distribute the heating of the support by zones, by conduction, being themselves heated by electric resistors for example.

 The casting line further comprises when the polyester support film is not used as a storage interlayer, means for separating the sheet of said support.

 To avoid optical defects of the sheet due to the presence of foreign bodies, the casting line may further comprise means preventing dust particles and other particles from being deposited on the manufactured sheet and possibly on the support, especially when the latter it is used as storage interlayer, and also cleaning means for removing these dust particles possibly already deposited.

 The means for preventing the deposition of particles may be physical screens. Thus, it is possible to place the entire casting line, or parts of this line, such as casting zones, and solidification in an enclosure containing filtered air and dedusting.

 The means for preventing the deposition of particles may also be electrostatic bars which ionize the atmosphere around the sheet.

 The means for cleaning the sheet may be brushes, blades acting as rakes, wiping elements, associated where appropriate with suction members.

 In a variant, the means supporting the polyester support film, generally excluding the location or locations for casting, are metal son stretched between two horizontal bars arranged laterally on either side of the casting line. These son can be placed at determined distances from each other, these distances are generally smaller near the downstream of the casting, where the cast material is still very fluid.

 One of the advantages of the use of metal son comes from the fact that the friction of the casting support sheet with these son are virtually eliminated and it follows that the static electricity created in particular by these friction is greatly reduced.

 On the other hand, these conductors son are likely to eliminate these electrical charges.

 Another advantage of the use of metal son lies in the fact that it removes dust grains that can be housed between the rigid support sheets and the flexible support stretched, and which are likely to damage the flexible support or still cause surface defects on the cast layers.

 In a variant of the device used to manufacture at least one layer of high-quality optical polyurethane on a polyester support film, two supports extending over the entire effective length of the casting line, placed on the along the lateral edges of the polyester support film, which associated with tensioning means allow to stretch the polyester support film like a drum skin. Such means are described in European Patent Publication 0 131 483 already cited.

 The preparation of examples of polyester support films used in the context of the invention for the manufacture of polyurethane layers is now described.

Support 1
1 - Preparation of an aqueous coating composition
To an aqueous dispersion of PVDF at 35% by weight of dry extract is added with stirring an amount of an aqueous dispersion containing 20% by weight of a sulfonated copolyester, sold under the trademark GEROL PS 20 by the company RHONE- POULENC CHIMIE sufficient to obtain an aqueous dispersion in which the PVDF represents 31% by weight of the composition and the sulphonated copolyester 2.2% by weight (total dry extract 33.2% by weight). This copolyester comprises, for 100 dicarboxylic acid units: 52 isophthalate units, 36 terephthalate units and 12 sulfo-5 isophthalate units; its diethylene glycol content is 13% by weight. It has a number-average molecular weight of 17,000 and a viscosity number of 556 μm at 250 ° C. on a solution of 1 g of polymer in 100 ml of a phenol / phenol mixture. O-chlorophenol in a 50/50 weight ratio.

2 - Preparation of a coated film
An ethylene glycol polyteraphthalate having a viscosity number of 580 and containing 0.4% by weight of calcium carbonate is extruded at a rate of 96 kg / h at 2750 ° C. by a slot die 450 mm wide. The tablecloth
PET is brought into contact with a cooling drum whose surface is maintained at 350 ° C., then stretched in the longitudinal direction at 750 ° C. (drawing velocity 20 m / mm, drawing ratio 3.2). 2 g / m 2 of the aqueous dispersion prepared above is then deposited on the mono-stretched film, by means of a coating device successively comprising: a leveling roller, a loading roller, a coating roller rotating at 13 m / min and a smoothing bar running at 7 m / min. The coated film is then subjected to transverse stretching at 95-1100 ° C (3.7) and then heat set at 225-2350 ° C. In this way, a film of 36 μm in thickness is obtained, one side of which has a coating of PVDF (0.2 g of solids per m 2).

On the coated film thus obtained was determined by the DAVENPORT method (ASTM D 1894-78) the coefficients of static friction (us) and dynamic (ud) of the coated face on the coated side. The results are as follows
us: 0.36
ud: 0.33
The uncoated film has the following coefficients of friction
us: 0.56
ud: 0.44
Support 2
An anti-adhesive composite film is prepared by in-line coating, between the longitudinal stretching and the transverse stretching, of a coextruded composite film consisting of a main PET layer A containing 0.03% by weight of silica bearing on each of its 1 layer (B) of an adhesion primer based on a copolyester with 5-isophthalate units. Prior to coating, the mono-stretched film is subjected to a corona treatment. The coating is carried out by means of a helio-report type device whose engraved roll has 120 cells of 40 μm in depth per cm 2.

The coating composition was obtained by addition of a 20% by weight aqueous dispersion of GEROL PS 20 to 1000 g of a 35% by weight PVDF suspension with stirring. The composition obtained contains 28.8% solids (20% PVDF and 8.8% sulphonated copolyester). The amount of aqueous composition deposited is 2 g / m 2
The film coated with a thickness of 50 m, comprises 0.2 g / m 2 of dry extract. It presents the following coefficients of friction
face end./face end. face end./face not end.

us 0.72 0.90 ud 0.61 0.66
Support 3
1 - Preparation of a grafted sulphonated copolyester
A latex containing 45% by weight of dry extract of a sulphonated copolyester is prepared using the polishing method described in Example 1 of the European patent application No. 0 260 203. For this purpose, a mixture of methacrylate of methyl, ethyl acrylate, methacrylic acid, crotonic acid and vinyl acetate, taken in the weight ratios of Example 1 of the aforementioned European application is polymerized in the presence of a quantity of sulfonated copolymer described in Example 1 of the present application, calculated so that said sulfonated copolyester constitutes 40% by weight of the dry extract of the latex obtained.

2 - Preparation of a coating composition
To 1000 g of the aqueous PVDF dispersion described in Example 1 is added with stirring the sufficient amount of graft copolymer latex 45% by weight of solids to obtain an aqueous dispersion in which the PVDF represents 30% by weight and the graft copolymer 3% by weight of the total composition (ie a total solids content of 33%).

3 - Preparation of a coated composite film
An anti-adhesive composite film is prepared by in-line coating of the polyester support film described in Example 2 with the aid of the composition described above, deposited at a rate of 2 g / m2 to obtain a coated film of 50 Wm comprising 0.2 g / m2 of anti-adhesive coating.

The film thus obtained has the following friction coefficients
face end./face end. face end./face not end.

us 0.74 0.79 ud 0.55 0.61
Supports 4 and 5
By operating as in Example 3, coated films F1 and F2 were prepared by coating the support film of Example 2 with aqueous dispersions respectively containing 26% and 20% by weight of PVDF and 5.5 and 9% by weight of the graft copolymer of Example 3 (respectively 31.5 and 29% by weight of dry extract). The films obtained have the following coefficients of friction
face end. / face end. face end. / non end face.

us Bd us ud Fl 0.71 0.59 0.62 0.56
F2 0.70 0.59 0.73 0.53
Support 6
A coated film is prepared by coating a bi-stretched film obtained by coextrusion of an ethylene glycol polyterephthalate containing 0.08% of silica and a sulphonated copolyester containing 5-isophthalic units; the coextruded film with a total thickness of 50 Wm comprises a sulfonated copolyester layer of 0.4 Wm on each side. The face intended to receive the coating has undergone a corona treatment.The aqueous coating composition which comprises 5% by weight of PVDF and 2.2% by weight of sulfonated copolyester described in Example 1 (ie 7.2 g of total solids content) is deposited on the composite film by means of a gravure-type coating system provided with an engraved ceramic roll having 50 lines 66 ssm deep per cm 2. The film speed is 30 m / min. The coated film then passes into 3 drying zones respectively at 90, 85 and 600C and then on a chill roll.

The resulting film which comprises 0.3 g / m 2 of anti-adhesive coating has the following coefficients of friction

<tb><SEP> Face <SEP> Coated / Face <SEP> Coated
<tb><SEP> I <SEP><SEP> I <SEP> I
<tb> Ws <SEP><SEP> 1 <SEP> 0.4 <SEP><SEP> I <SEP>
<tb> I <SEP> Bd <SEP> 1 <SEP> 0.3 <SEP><SEP> I <SEP>
<tb> l <SEP><SEP> ~~~~ <SEP> I <SEP> I <SEP>
<Tb>
The uncoated film has as coefficients of friction: us: 0.5 and ud: 0.4)
Supports 7 to 9
The aqueous latex used was obtained by polymerization according to the process described in Example 1 of European Application No. 0 260 203 of vinyl acetate (5% by weight), of methyl methacrylate (44.5% by weight ), ethyl acrylate (36.5% by weight) methacrylic acid (11% by weight) and N-methylolmethacrylamide (3% by weight) in the presence of the sulfonated copolyester of Example 1 (40%) by weight of total monomers). The latex thus prepared has a solids content of 42% by weight and a viscosity at 15% of 34,000 CPS.

Addition compositions were prepared by adding to 1000 g of PVDF aqueous dispersion at 35% dry extract of an adequate amount of the aqueous latex described above to obtain the coating compositions C1, C2 and C3 which have the following compositions

<tb><SEP> PVDF <SEP><SEP> COPOLYESTER <SEP> SULFONE <SEP> I
<tb><SEP> I <SEP><SEP> EN <SEP> WEIGHT <SEP> I <SEP><SEP> GRAFT <SEP>% <SEP> EN <SEP> WEIGHT <SEP> I
<tb> I <SEP><SEP> Cl <SEP> I <SEP><SEP> 7.5 <SEP> 1 <SEP> 0.75 <SEP><SEP> I <SEP>
<tb><SEP> C2 <SEP> 1 <SEP><SEP> 20 <SEP> 1 <SEP> 8.8 <SEP><SEP> I <SEP>
<tb><SEP> C3 <SEP> C3 <SEP> 5 <SEP> 5 <SEP> I <SEP> 2,2 <SEP> I
<tb> I - <SEP>
<Tb>
Operating as in Example 6, films were prepared
F 1, F 2 and F 3 on the coextruded film of Example 6 by deposit of 0.45 g / m 2, respectively; 1.7 g / m2 and 0.4 g / m2 of dry extract on each film.

The films thus obtained have the following coated friction coefficients on the coated side

<tb><SEP> I <SEP> I <SEP> I
<tb><SEP> I <SEP> us <SEP> I <SEP> ud <SEP> I
<tb> F1 <SEP> 0.4 <SEP> I <SEP> | <SEP> 0.3
<tb> F2 <SEP> 0.4 <SEP> F2 <SEP> | <SEP> 0.3 <SEP> 1
<tb> F3 <SEP> F3 <SEP> | <SEP> 0.4 <SEP> 1 <SEP><SEP> 0.3
<Tb>
The supports described above are used as supports for the manufacture of polyurethane layers as illustrated in the following examples
The polyurethane layers which can be manufactured according to the invention are those described for example in the French patent 2,398,606 and European publications 0 132 198, 0 133 090, 0 190 517.

 When it is desired to manufacture a two-layer sheet for use in safety glazing as described in European Patent Publication 0 132 198, a first layer is first made which may be either the adhesive layer having energy absorber (AE layer), ie the thermosetting polyurethane layer. And on this first layer, the second layer is formed.

 It is thus possible to first manufacture a thermosetting polyurethane layer by pouring the mixture of components onto the casting support. After polymerization of the monomers and formation of a thermosetting layer with a thickness of between 0.1 and 0.8 mm, for example, the reaction mixture is poured into the components of the layer having energy-absorbing properties.

 It is also possible to proceed in an inverse manner, that is to say by first forming the layer having energy absorber properties (layer AE).

EXAMPLES 1 TO 9
On the supports 1 to 9 described above, a homogeneous mixture of
1000 g of a polyether with a molecular weight of approximately 450 obtained by condensation of 1,2-propylene oxide with 2,2-bis (hydroxymethyl) -1-butanol and having a content of free hydroxyl radicals from about 10.5 to 12%, containing 1% by weight of a stabilizer, 0.05% by weight of a catalyst, namely dibutyltin dilaurate and 0.1% by weight of a coating agent,
1020 g of a biuret of 1,6-hexanediisocyanate having a content of free isocyanate radicals of about 23.2%.

 A pouring head such as that described in French Patent Publication 2,347,170 is used. A uniform layer is formed which, after polymerization under the effect of heat, for example approximately 15 minutes at 1200 ° C., has a thickness of approximately 0.19 mm and self-healing properties.

 To manufacture the layer having energy-absorbing properties, the polyol component is prepared beforehand by mixing a polytetramethylene glycol of molecular mass 1000 with 1,4-butanediol and a polycaprolactonetriol, the proportions of the three constituents being such as polytetramethylene glycol. gives 0.35 equivalents in hydroxyl groups, while butanediol-1,4 gives 0.55 and the triol 0.10.

 To the polyol component, a stabilizer is incorporated at a rate of 0.5% by weight of the total weight of the polyol component and of the isocyanate component, a surfactant at a rate of 0.05% by weight calculated in the same way and a catalyst with namely dibutyltin dilaurate at a rate of 0.02% by weight calculated in the same manner as previously.

The isocyanate component used is 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (IPDI) having urea functions obtained by partial hydrolysis of IPDI and having a group content
NCO of about 31.5% by weight.

 The components are taken in such quantities that the NCO / OH ratio is 1.

 After degassing under vacuum components, the mixture heated to about 400C is poured using a casting head as described in French Patent Publication 2,347,170, on the self-healing polyurethane layer previously formed. A layer of about 0.60 mm in thickness is thus formed which is subjected to a polymerization cycle consisting of 25 minutes of heating at approximately 1200 ° C.

 The two-ply sheet is removed from the polyester backing and can easily be handled, stored or used immediately after manufacturing the laminated glazing.

 The sheet has the optical quality necessary for its use in a safety glazing.

EXAMPLES 10 TO 18
The procedure is as in Examples 1 to 9, except that to form the polyurethane layer having self-healing properties, a homogeneous mixture of - 942 g of a trifunctional polycaprolactone having a
free OH radical content of 9.3% by weight, containing
0.015% by weight of dibutyltin dilaurate, 0.1% by weight
weight of a fluoroalkyl ester as a spreading agent and
1% by weight of a UV protection agent

- 1000 g of a triisocyanurate based on 1,6-hexamethylene
diisocyanate, having a free NCO radical content of
21.5% by weight.

 The layer is polymerized under the effect of heat, for example 15 minutes at 1200C.

 The layer having energy absorbing properties is then produced.

 The two-layer sheet is removed from the support. It presents the optical quality needed for use in safety glazing.

Claims (30)

 1. Application of a non-stick polyester film as a support for the formation of sheets of plastics material comprising at least one layer of polyurethane of good optical quality by supplying at least one liquid mass on said movable horizontal plane support, characterized in that the non-adhering polyester film is constituted by a semi-crystalline oriented polyester support film (A) comprising on at least one of its faces a coating consisting of  a) a fluorinated polymer and  b) an effective amount of a water-dispersible polyester derived from at least one aromatic dicarboxylic acid and at least one diol and having a plurality of sulfonyloxy groups of the general formula  (I) (SO3) = M in which  n is 1 or 2  M represents a hydrogen atom, an alkaline or alkaline-earth metal, an ammonium cation or a quaternary ammonium cation.  2. Application according to claim 1 characterized in that the support oriented polyester film is constituted by a polymer comprising at least 80 mol% of units derived from at least one aromatic dicarboxylic acid and ethylene glycol.  3. Application according to claim 2 characterized in that the support oriented polyester film is constituted by a polymer comprising at least 80 mol% of ethylene glycol terephthalate units or naphthalene ethylene glycol dicarboxylate.  4. Application according to any one of claims 1 to 3 characterized in that the support oriented polyester film has a thickness of between 20 and 200 microns.  5. Application according to any one of claims 1 to 4 characterized in that the polyester support film has on the side receiving the antiadherent coating a primary coating of adhesion.  6. Application according to claim 5 characterized in that the primary adhesion coating is constituted by a sulfonated copolyester.  7. Application according to any one of claims 1 to 6 characterized in that the face of the support film receiving the release coating has been subjected to a corona treatment.  8. Application according to any one of claims 1 to 7 characterized in that the dispersible polyester is a copolyester comprising a plurality of units derived from at least two dicarboxylic acids, one of which has at least one sulfonyloxy group in its molecule and a plurality of units derived from at least one aliphatic diol.  9. Application according to claim 8 characterized in that the number of units derived from a dicarboxylic acid containing sulfonyloxy group for a total of 100 units derived from dicarboxylic acids is from 2 to 30.  10. Application according to any one of claims 1 to 9 characterized in that the dispersible polyester is a copolyester comprising a plurality of units derived from at least one unsulfonated dicarboxylic acid taken from the group of terephthalic, isophthalic and phthalic acids.  11. Application according to any one of claims 1 to 8 characterized in that the dispersible polyester is a copolyester comprising a plurality of units derived from tere and isophthalic acids.  12. Application according to claim 9 characterized in that the dispersible polyester is a copolyester in which the number of terephthalate units represents from 20 to 99% of the total number of terephthalate and isophthalate units.  13. Application according to any one of claims 1 to 10, characterized in that the water-dispersible polyester comprises a plurality of units derived from 5-isophthalic acid.  14. Application according to any one of claims 1 to 11 characterized in that the dispersible polyester comprises a plurality of units derived from at least one aliphatic diol taken from the group of ethylene glycol and its oligomers of formula HO- ( Where n is an integer from 2 to 10.  15. Application according to any one of claims 1 to 14 characterized in that the dispersible polyester has been modified by grafting at least one acrylic monomer.  16. Application according to claim 15 characterized in that the monomer of acrylic nature meets the general formula

 in which  R represents a hydrogen atom or a lower alkyl group, optionally substituted with a hydroxyl group;  Y represents a hydroxycarbonyl alkoxycarbonyl functional group of formula -CoeR # in which R 1 is an alkyl radical containing from 1 to 20 carbon atoms, linear or branched (optionally substituted with a hydroxyl radical); nitrile; amide of formula -CON (R2, R3) in which R2 and R3, which may be identical or different, represent a hydrogen atom or a linear or branched alkyl radical containing from 1 to 20 carbon atoms.  17. Application according to any one of claims 15 to 16 characterized in that the acrylic monomer is taken from the group formed by acrylate and methyl methacrylate, acrylate and ethyl methacrylate, acrylic and methacrylic acid, acrylamide and methacrylamide.  18. Application according to any one of claims 15 to 17 characterized in that a minor amount of one or more non-acrylic ethylenic monomers are associated with the acrylic monomer.  19. Application according to any one of claims 15 to 18 characterized in that at least one crosslinking monomer is associated with the acrylic monomers of formula (II).  20. Application according to claim 19 characterized in that the amount of crosslinking monomer is up to 5 mol% of the acrylic monomer of formula (II).  21. Application according to claim 19 characterized in that the crosslinking monomer is a polyethylenic monomer.  22. Application according to claim 19 characterized in that the crosslinking monomer is a hydroxyalkyl (meth) acrylamide.  23. Application according to any one of claims 15 to 22 characterized in that the modified dissipable polyester contains from 0.1 to 15% by weight of at least one external crosslinking agent taken from the group formed by the formophenolic resins and the amine-formaldehyde resins.  24. Application according to any one of claims 1 to 23 characterized in that the fluoropolymer is taken from the group formed by polymers and copolymers of vinylidene fluoride, trifluorochloroethylene, tetrafluorochloroethylene, hexafluoropropylene between them and or with non-fluorinated monomers.  25. Application according to any one of claims 1 to 24 characterized in that the amount of polymer dispersible in water, modified or not, present in the coating is from 5% by weight to 50% by weight of the fluoropolymer.  26. Application according to any one of claims 1 to 25 characterized in that the amount of coating expressed in g of dry extract per mz of oriented support film is between 0.1 and 0.4 g / m2.  27. Application according to one of claims 1 to 26, the manufacture of a thermosetting polyurethane layer by supplying the reaction mixture of the polyurethane components on the support film.  28. Application according to one of claims 1 to 26, the manufacture of a polyurethane layer having energy absorber properties by supplying a reaction mixture of the polyurethane components on the support film.  29. Application according to one of claims 1 to 28 for the manufacture of a sheet comprising two layers of polyurethane, a thermosetting polyurethane layer and a polyurethane layer having energy absorbing properties.  30. Plastic sheet comprising at least one polyurethane layer obtained by the implementation of the application according to one of claims 1 to 29.