GB2146647A - Thermoplastic synthetic moulding compositions containing UV absorbents - Google Patents

Abstract

Thermoplastic synthetic moulding compositions suitable for the production of optically high grade mouldings are prepared from a copolymer which includes units of radically polymerisable monomers which contain in their molecule components giving protection against UV light. The specified monomers include those in which the UV stabilising group is a 2-hydroxyphenyl-benzotriazole, 2-hydroxy-benzophenone, 2-hydroxyacetophenone, alpha -cyano- beta , beta -diphenyl, hydroxy-containing benzoic acid ester, oxalanilide, p-aminobenzoic acid ester or 6,8-dialkyl-4-oxo-5-chromanyl group.

Description

SPECIFICATION Thermoplastic synthetic moulding compositions containing UV absorbents and a process for their preparation The present invention relates to thermoplastic synthetic moulding compositions containing UV absorbents, to a process for their preparation and to mouldings produced from them.

It has been found that certain high-energy components of light have a considerable detrimental effect on biological and other everyday materials. Technological efforts have therefore been made to protect particularly sensitive materials from such light components, particularly UV light. Frequently, this protection consists of a UV light-absorbing covering layer. The use of stabilised plastics such as polyolefins, PVC, polystyrene, polycarbonate and polyvinylacetate is of major practical importance. The principle of light stabilisation is based on the prevention of the primary photochemical reaction of the uptake of energy by absorption or the reversal of this reaction. (Cf. Ullmanns Encyclopaedia der Techn. Chemie, 4th Edition, Volume 15, pages 253-273, Verlag Chemie, 1978).

Under certain conditions, plastics may be stabilised in bulk by the addition of standard commercial UV stabilisers. Since light absorption increases with layer thickness according to Lambert-Beerschen's Law, an adequate protective effect is generally only achieved with a layer thickness of more than 100 um. Usually the amounts of UV absorbants added to the composition are in the range of from 0.1 to 5% by weight. In consequence, the protection of relatively thin bodies such as fibres, ribbons and very thin films cannot be satisfactorily achieved.

Another known method of protection is the use of the UV absorbing effect of polymerisable monomers which are absorbent in the UV range (cf. for example S. Yoshida, O. Vogl, Makromol. Chem. 183,259-279 (1982). Tried and tested UV absorbents have mostly been derived from 2-hydroxybenzophenone, 2-hydroxyphenylbenzotriazole, a-cyano-ss-phenylcinnamic acid, 4-aminobenzoic acid, salicylic acid and oxalanilides and they contain polymerisable units such as a vinyl, allyl, acryloyl or methacryloyl group. They may have a stabilising effect in certain polymers or copolymers. It is known that polyethylene may be stabilised by graft copolymerisation with UV-absorbent monomers.In Chem.Abstr. 93, 72 000d, the stabilisation of LD-polyethylene by surface grafting with 2-hydroxy-4(3-methacryloxy-2-hydroxypropoxy)benzophenone is recommended (according to Chem.Abstr. 94, 140 375C N-methacryloylbenzoxazolinone is also suitable for this purpose); a similar procedure is described in Chem.Abstr. 94, 48206q. Surface grafting of PVC with 2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)-benzophenone is the subject of a study in Chem.Abstr. 86, 121979k. Co polymers of chloroprene and styrene with 2-benzothiazolthiolmethacrylate may be prepared according to Chem.Abstr. 95, 63499b. They are used as vulcanisation accelerators for neoprene and SKS-30 rubber.The stabilisation of PVC with benzothiazolinethione methacrylate is described in Chem.Abstr. 92, 59614f.

Vinyl 4-vinyl-o-cyano-ss-phenyl-cinnamate is described as a monomer for homopolymers and copolymers with styrene and methylmethacrylate (MMA) (Chem.Abstr. 95, 187714n); similarly, 6,8-dimethyl-4-oxo-5- chromanylmethylacrylate has been copolymerised with MMA or with vinyl chloride. (Chem.Abstr. 95, 95740y). DE-OS 1520458 describes a copolymer of a-olefins and an o-hydroxybenzophenone(meth)acrylate. These copolymers should be suitable, inter a/ia, for the production of self-supporting films or films on carriers. Similarly, 2-hydroxybenzophenone derivatives with (meth)acryloyloxy groups in 4 positions are recommended as comonomers with styrene, acrylonitrile and/or MMA (Chem.Abstr. 96, 53957f).The copolymerisation of 6,8-dimethyl-4-oxo-5-chromanyl-methacrylate, with M MA inter alia, is described in Chem.Abstr. 90, 169084z. According to Europ.Polym.J. 1977(13)915-19 (Chem.Abstr. 88, 191967v) 4-benzoyl-3-hydroxyphenylacrylate may be copolymerised with ABS.

US-PS 4 260 768 proposes 2-(2H-benzotriazol-2-yl)-4-alkylphenolacyl esters as copolymerisable UV absorbers, for use with styrene or vinyl pyrrolidone for example. Copolymerisable 4-acryloyloxybenzol-1 alkyl-1-phenylhydrazones are described as UV stabilisers in US-PS 4247714 and 4-alkoxy-2' acryloxybenzazines are described as UV stabilisers in US-PS 4260 809. Other comonomers include 2-cyano-3,3-diphenylacryloxy)alkylene-ethylene ethers (US-PS 4202 834) and -acrylic acid esters (US-PS 4 178 303). Sterically hindered piperidine derivatives have also been proposed as copolymerisable UV absorbents (DE-OS 26 51 511, DE-OS 22 58 752, DE-OS 20 40 983, DE-OS 23 52 606).

Objects with predetermined optical properties may be produced from plastics, particularly acrylic glass, using casting, pressing, swaging, injection moulding, extrusion and extraction processes. Problems arise both in the protection of the plastics objects themselves from the undesirable effects of UV light and also in the prevention of the passage of undesirable light components, particularly the UV light. Such objects include high grade optical equipment, for example lenses, contact lenses, optical filters, prisms, lattices, mirrors, light conductors, reflectors, optical voltage models and artificial eyes.

It was found that in the production of mouldings which were to be the subject of stringent optical requirements, it was not sufficient to add migration-prone UV absorbents to the moulding compositions, since unpreventable and uncontrollable gradients and inhomogeneities in the UV absorbent content of the mouldings, which might only occur or be noticed some time after moulding, were unacceptable. Moreover, even if the materials were perfectly homogeneous and completely isotropic, problems arose as a result of the fluctuations and thermal secondary manifestations in high-grade optical systems triggered by the presence of the UV absorbents in the polymer.

One possible solution to this problem was the application onto the mouldings of a barrier layer against short-wave radiation, as was commonly found in the field of radiation protection since by this method there would have been a significantly better chance of producing satisfactory mass-produced products reproducibly within given specifications. Such additional layers could, however be detrimental to the optical properties.

There is therefore a need for moulding compositions which are protected from or offer protection from the harmful effects of UV light, and which would provide mouldings which will not only meet stringent requirements in terms of their optical properties and mechanical qualities, but also in which any other qualities essential in practical use are if possible not affected.

We have now found that it is possible to prepare thermoplastic synthetic moulding compositions containing UV absorbants with very good properties whilst substantially avoiding the disadvantages described above.

According to the invention there is provided thermoplastic synthetic moulding compositions for the production of optically high-grade mouldings, wherein the moulding compositions include a copolymer P which is prepared from, inter alia, radically polymerisable monomers which contain in their molecule components effective for protection against UV light.

It is greatly preferred that the moulding compositions satisfy the optically favourable prerequisites of acrylic resins, i.e. if the other known monomers are wholly or predominantly (i.e. up to 50% by weight, based on all the monomer components which do not give UV protection) derivatives of acrylic and/or methacrylic acid, particularly esters thereof.

The monomers giving UV protection preferably absorb not less than 10% of the irradiated light in the wavelength range from 250 to 350 nm at a concentration of 0.002% in chloroform (for spectroscopy) and in a layer thickness d of 5 mm. The protecting monomers are different from the aromatic components of conventional thermoplastics. The incorporation ofthe monomers giving UV protection (preferably 0.1 to 20% by weight, preferably 3 - 12% by weight, and especially 5 - 10% by weight, based on all the monomers) into the copolymer P may be carried out according to known methods of polymerisation, depending to some extent on the chemical nature of the monomers. The polymerisable unit is preferably an acrylic, methacrylic, vinyl or allyl group, all of which can be subjected to radical polymerisation in a manner known perse.It is particularly preferred to incorporate monomers of formula I

wherein R represents a hydrogen atom or a methyl group, Y represents an oxygen atom or a group -NR2 wherein R2 is a hydrogen atom or an alkyl group with 1 to 6 carbon atoms, and n represents 0 or 1 and Z represent either (a) a 2-hydroxyphenyl-benzotriazole group

wherein R3 represents a hydrogen atom or an alkyl group with 1 to 12 carbon atoms and q represents 0 or a number from 1 to 4, the bonding of Z being effected via the oxygen atom or the -(CH2)q~ radical or directly to the phenyl group, the remaining free position being occupied by a hydrogen atom; if desired, halogen substituents may also be present, and the benzotriazole group may be substituted by an alkyl group with 1 to 4 carbon atoms or a halogen atom; or (b) a 2-hydroxy-benzophenone or -acetophenone group

wherein m represents 0 or 1 and X represents an alkylene group with 1 to 4 carbon atoms optionally substituted by hydroxy groups and R4 represents an optionally substituted phenyl or methyl group; or (c) an α-cyano-ss,ss-diphenyl group

wherein p represents an integer from 1 to 4 and P5 and R5' represent a phenyl group optionally substituted by a C14 alkyl group; or (d) a hydroxyl group containing benzoic acid ester

wherein one of the two groups P6 or R6 represents a hydroxy group and the other represents a hydrogen atom and R7 represents hydrogen or an alkyl group with 1 to 10 carbon atoms, the linkage being effected via any free unsubstituted position on the phenyl group; or (e) an oxalanilide

wherein P8 and Rg, which may be the same or different, represent a hydrogen atom or an alkyl group or alkoxy group with 1 to 8 carbon atoms and r represents 0 or 1, the bonding of Z being effected via the oxygen or directly to one of the phenyl groups, the other, free position being occupied by hydrogen; or (f) p-aminobenzoic acid ester derivatives

wherein Rlo and R, which may be the same or different, represent a hydrogen atom or an alkyl group with 1 to 6 carbon atoms; or (g) 6,8-dialkyl-4-oxo-5-chromanyl compounds

wherein P12 and P13, which may be the same or different, represent alkyl groups with 1 to 4 carbon atoms; with the proviso that the group Z should not be bonded into the polymers P via an oxygen belonging to the group if n represents 1.

If the monomers of formula I carry halogen substituents, these are preferably bromine or chlorine substituents. Particularly preferred examples of compounds offormula l(a), are 2hydroxyphenylbenzotriazole compounds, which may be prepared, for example, in accordance with US Patent 3 159 646 and 3 399 173.

Preferred monomers include: 2-(2'-hydroxy-3'-methacryloylamidomethyl-5'-alkyl)-benzotriazole (wherein alkyl represents methyl or octyl), 2-(2'-hydroxyphenyl)-5-methacryloylamido-benzotriazole 2-(2'hydroxyphenyl)-5-methacryloylamido-methylbenzotriazole, and also 2-(2'-hydroxy-5-vinylphenyl)-2H- benzotriazole.

The monomers of formula l(b) are particularly preferred, especially derivatives of 2 hydroxybenzophenones, for example those which can be obtained according to US Patent 3 107 199, particularly 2-hydroxy-4-methacryloxybenzophenone, 2-hydroxy-4-acryloxybenzophenone, 2-hydroxy-4- methacryloxy-5-tert.butyl-benzophenone,2-hydroxy-4-methacryloxy-2',4'-dichlorobenzophenone,2- hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone, 4-(aI lyloxy)-2-hydroxybenzophenone, 2,4- dihydroxy-4'-vinylbenzophenone, and also derivatives of hydroxyacetophenone obtainable according to BE-PS 629480.

Compounds of formula l(c) are also preferred particularly vinyl compounds such as vinyl 4-ethyl-a-cyano (3-phenylcinnamate and unsaturated ethers such as 2-cyano-3,3-diphenylacryloxy)alkylene-ethylene ethers and (meth)-acrylic acid derivatives such as 2-cyano-3,3-diphenylacryloxy)alkylene-acrylic acid esters and 2-(acryloyl)oxyethyl-2-cyano-3,3-diphenylacrylate.

The preparation of the above-mentioned monomers of formula I is either known from the literature or else may be prepared by known methods or analogously to methods which are knownperse. The proportion of monomers which contain components giving protection from UV light in the molecular structure, particularly the compounds of formula i, is preferably from 0.1 to 20% by weight, more preferablyfrom 5 to 10% by weight, based on the weight of the copolymer P.

Compositions wherein the copolymer P is an acrylic resin are particularly preferred. These acrylic resins are generally copolymers produced from the monomers giving protection from UV light, particularly the monomers of formula I, on the one hand one or more esters of acrylic and/or methacrylic acid of formula II

wherein R; represents a hydrogen atom or methyl group, R14 represents an alkyl group with 1 to 8 carbon atoms or a phenyl group or aralkyl group with 7 - 12 carbon atoms.

Monomers of general formula III

wherein R' represents a hydrogen atom or methyl group, B represents a group - 0 - or No15, A represents a hydrocarbon bridge with 2 to 6 carbon atoms and Q represents a hydroxy, methoxy to hexyloxy group or a group -NR16R17, whilst R15 represents a hydrogen atom or an alkyl group with 1 to 6 carbon atoms and R16 and R17 represent alkyl groups with 1 to 6 carbon atoms, may also be incorporated. if such monomers of formula Ill are also used, the sum of the proportions of monomers of general formulae II and ill represents 70 - 99.9% by weight, based on the total weight of acrylic resin (copolymer P), (the monomers of formula II and Ill may replace one another).Monomers may also be used selected from those of formula IV

wherein R19 represents a nitrile group, a phenyl group optionally substituted by a ClA alkyl group, a heterocyclic group or a -CH2 = CH2 group. R20 represents a hydrogen atom or a methyl group; and R8 represents a hydrogen atom or, together with R19, forms an anhydride group

R20 in such a case representing a hydrogen atom; or R19 represents a group

wherein P21 represents an alkyl group with 1 to 6 carbon atoms, with the proviso that in this case R18 and P20 represent hydrogen atoms.When monomers of formula IV are used, they are preferably employed in an amount of from 0 to 25% by weight, based on the weight of acrylic resin (copolymer P), with the proviso that the Vicat softening temperature (according to DIN 53 460) of the polymer P prepared from monomers I, II and optionally III, and/or IV does not fall below 65"C.

Copolymers of methylmethacrylate (MMA) with compounds of formula land particularly with other comonomers of formula II, for example the methyl ester of acrylic acid and the ethyl, butyl, ethylhexyl and phenylethyl esters of acrylic and/or methacrylic acid, wherein the monomers of general formula II make up 70 - 99.9% by weight of the copolymer P and those of general formula III make up 0 - 25% by weight, are particularly preferred.

Generally, the proportion of methylmethacrylate is at least 60% by weight, preferably 65 - 90% by weight, more preferably 75 + 10% by weight, and the proportion of other comonomers of formula II is0 to 30% by weight, preferably 5 - 25% by weight, more preferably 18 + 5% by weight, based on the weight of copolymer P.

However, monomers of formula III e.g. hydroxyethyl or hydroxypropylacrylate or methacrylate or the corresponding alkylethers, particularly the methyl and ethylethers may also either wholly or partially, replace the monomers of formula II, i.e. they may be present in amounts of from 0 to 99.9% by weight, preferably in amounts from 5 to 20% by weight, in the copolymer P. For example, copolymers consisting of 0.1 - 20% by weight of monomers of formula I together with 80 - 99.9% by weight of a hydroxyalkyl(meth)acrylate satisfy the requirements imposed on so-called "soft lenses" to a particularly high degree.Finally, one or more comonomers of formula IV particularly acrylonitrile, styrene and/or the alkyl derivatives thereof such as o'-methylstyrene, p-methylstyrene, maleic acid anhydride and heterocyclic vinyl compounds, particularly N-vinylpyrrolidone, may also be present in the copolymer, in amounts of from 0 to 25% by weight, whilst the proportion of the individual monomers of formula IV is generally from 2 - 15% by weight.

The copolymer P may also be synthesised predominantly from monomers of formula II other than MMA, for example from other esters such as ethylmethacrylate and isobutylmethacrylate.

The acrylic resin forming the moulding composition may also be a mixture of the copolymer P with other poly(meth)acrylates, for example with the polymers produced by polymerisation or copolymerisation of the monomers of formulae II - IV (in proportions corresponding to copolymer P without monomers offormula 1), whilst preferably the content of monomers of formula I in the entire moulding composition is not less than 0.1% by weight, more preferably 3% by weight.

The molecular weights of the acrylic resins, particularly the copolymers P, are desirably in the range from 10,000 to 500,000, preferably 120,000 to 220,000. The specific density is preferably from 1.3 to 2.3.

The term "thermoplastic synthetic moulding compositions for the production of optically high-grade mouldings" as used herein refers to those compositions which yield mouldings (possibly after suitable surface treatment) which do not show any cloudiness or turbidity of the material (in accordance with DIN 5036) exceeding a value of 0.5%, preferably 0.3%.

Production of the thermoplastic moulding compositions according to the invention may be by any of the polymerisation procedures used in the production of conventional moulding compositions. Particularly preferred are discontinuous and continuous bulk polymerisation (Winnacker-Kijchler: Chemische Technologie, Volume 6, Organische Technologie II, page 414, Carl Hanser, 1982) and suspension polymerisation (Schildknecht/Skeist "Polymerization Processes" (Volume 29 of High Polymers, Wiley-lnterscience 1977,) page 133).

The initiators used are azo compounds (prototype: azoisobutyric acid nitrile AIBN) or organic peroxides such as diarylperoxides or peresters (prototype: dibenzolyperoxide, dilauroylperoxide). Peroxydicarbonates, should not be used owing to their reactivity with the mercaptans orthioethers used as regulators. The nature and quantity of initiator used depend essentially on the nature of the method of polymerisation chosen. The quantities used are preferably between 0.01 and 1% by weight, based on the total weight of all the monomers. The adjustment of molecular weight is carried out, particularly in the case of PMMA moulding compositions, using mercaptans, e.g. alkylmercaptans or esters of thioglycolic or mercaptopropionic acid with mono- or polyhydric alcohols in quantities of between 0.1 and 1%, preferably between 0.2 and 0.5%. As is usual in such production methods, longer-chained alcohols, esters or carboxylic acids such as stearyl alcohol or stearic acid, may be used as the lubricants or mould release agents. As regards other additives, there are no particular restrictions in the case ofthe PMMA moulding compositions provided that these additives do not impair the optical qualities.

In the case of discontinuous bulk polymerisation, the additives are appropriately dissolved in the monomer mixture, the solution packed into foil bags (analogously to BE-PS 695 342) and polymerisation carried out in a water bath at about 50"C over about 22 hours. In order to increase the final conversion, polymerisation is appropriately continued at an even higher temperature (about 1 100C) perhaps in a drying cupboard for a further 10 hours or so. The polymer can then be ground up in the usual way and then degassed using, for example, an extruder.

The optically high-grade mouldings are preferably produced by means of bulk polymerisation which may be started either by means of suitable peroxides or azo compounds known per se, or, if there is sufficiently intensive radiation, by means of UV irradiation. The mouldings may be mechanically produced in a known manner from the polymer in sheet or strip form, if necessary, with the usual precautions or polymerisation may be carried out on suitable moulding material by the spin casting process.

Objects made from compositions according to the invention have advantages over objects made according to the prior art. For example, soft contact lenses prepared from compositions of the invention give considerable protection to the eye, for example, against the irradiation of light and the UV absorbers have a long-lasting activity without any noticeable migration. The freedom of migration of the UV absorber is particularly important in the case of lenses implanted in the eye, such as those used, for example, after cataract operations to replace the diseased natural lenses of the eye.

The following non-limiting Examples illustrate the invention: Examples 1. Preparation ofthe copolymers P1 according to the invention: 72 parts by weight of methylmethacrylate, 18 parts by weight of butyl methacrylate and 10 parts by weight of 2-(a-cyano-sslss-diphenylacryloyloxy)-ethyl-1-methacrylate (monomer IA as below) are combined with 0.36 parts of dodecylmercaptan and 0.2 parts of dilauroylperoxide and polymerised at 50"C in a water bath for 22 hours.After tempering (10 hours, 11 0'C) a clear, light yellow material is obtained with a reduced viscosity nsp/c of 65 ml/g (20 , CHCI3). [msp/cwas generally measured at 20"C in CHIC13 [ml/gl]. For the method of measurement see Zeitschrift f. Elektrochemie 1937, page 479].The following copolymers may be prepared analogously (Table 1), whilst the following abbreviations were used for the monomers (compounds of formula 1) which contain in their molecule components giving protection against UV light: Monomer IA : 2-(a-Cyano-ss,ss-diphenylacryloyloxy)ethyl-1-methacrylate Monomer IB : 2-(2'-Hydroxy-3'-methacrylamidomethyl-5'-octyl-phenyl)benzotriazole Monomer IC : 2-Hydroxy-4-(2-hydroxy-3-methacryoyloxy)-propoxy-benzophenone Monomer ID : 2-(a-Cyano-ss,ss-diphenylacryloxy)ethyl-1-methacrylate Monomer IE : 2-Hydroxy-4-methacryloyloxy-benzophenone Monomer IF : 2-Hydroxy-4-acryloyloxyethyloxy-benzophenone Monomer IG :N-(4-Methacryloylphenol)-N-(2-ethylphenyl)-oxalic acid diamide (of the SANDUVOR type made by Messrs. SANDOZ AG) Monomer IH : Vinyl 4-ethyl-a-cyano-p-phenyl cinnamate Monomer IJ : 2-(2-Hydroxy-5-vinylphenyl)-2-benzotriazole TABLE 1 Copolymer P Compound of formula I No.Composition according to compounds of formulae II-IV #spezic = [ml/g] in parts by weight (20 C; CHCl3) P 2 Methylmethacrylate [74], Butylmethacrylate [18], IB [ 8] 62 P 3 Methylmethacrylate [73], Butylmethacrylate [20], IC [ 7] 93 P 4 Methylmethacrylate [67], Butylmethacrylate [18], Methacrylate [3] Styene [ 3] ID [9] 93 P 5 Methylmethacrylate [70], Methylmethacrylate [22], IB [ 8] 138 P 6 Methylmethacrylate [68], Methylmethacrylate [20], IE [12] 111 P 7 Methylmethacrylate [72], Ethacrylate [18], IA [10] 120 P 8 Methylmethacrylate [72], Ethacrylate [18], IF [10] 141 P 9 Methylmethacrylate [72,5], Butylacrylate [17,5], IA [10] 153 P 10 Methylmethacrylate [77], Butylacrylate [13], IA [10] 110 P 11 Methylmethacrylate [72], Butylacrylate [20], IB [ 8] 137 P 12 Methylmethacrylate [77], Butylacrylate [15], IB [ 8] 98 P 13 Methylmethacrylate [85], 2-Ethylhexylmeth- [ 7], IG [ 8] 137 acrylate P 14 Methylmethacrylate [73], Phenylethylmeth- [17], IH [10] 97 acrylate P 15 Methylmethacrylate [82], Hydroxypropylmeth- [ 8], IE [10] 89 acrylate P 16 Methylmethacrylate [76], Ethoxyethylmeth- [15], IF [ 9] 98 acrylate P 17 Methylmethacrylate [76], Acrylonitrile [13], IG [11] 98 P 18 Methylmethacrylate [65], Maleic acid anhydride [ 9], Styrene [13] IJ [13] 74 P 19 Ethylmethacrylate [90], IA [10] 132 P 20 Ethylmethacrylate [92], IB [ 8] 120 P 21 Isobutylmethacrylate [92], IA [ 8] 136 P 22 Hydroxyethylmethacrylate [75], N-Vinylpyrrolidone [17], IA [ 8]

Claims (22)

1. Thermoplastic synthetic moulding compositions for the production of optically high-grade mouldings, wherein the moulding compositions include a copolymer P which is prepared from, interalia, radically polymerisable monomers which contain in their molecule components effective for protection against UV light.

2. Thermoplastic synthetic moulding compositions as claimed in claim 1, wherein the proportion of the monomers giving protection against UV light is 0.1 to 20% by weight, based on the copolymer P.

3. Thermoplastic synthetic moulding compositions as claimed in either claim 1 or claim 2, wherein the monomers giving protection against UV light absorb not less than 10% of the irradiated light in a wavelength range of between 250 and 350 nm, in a concentration of 0.002% in chloroform and in a layer thickness d of 5 mm.

4. Thermoplastic synthetic moulding compositions wherein the polymerisable unit of the radically polymerisable monomer is an acrylic, methacrylic, vinyl or alkyl group.

5. Thermoplastic moulding compositions as claimed in any one of claims 1 to 4, wherein the monomers containing components which give protection against UV light are radically polymerisable unsaturated compounds of formula I

wherein R1 represents a hydrogen atom or a methyl group, Y represents an oxygen atom or a group -NR2 wherein P2 is a hydrogen atom or an alkyl group with 1 to 6 carbon atoms, and n represents 0 or 1 and Z represents either (a) a 2-hydroxyphenyl-benzotriazole group

wherein P3 represents a hydrogen atom or an alkyl group with 1 to 12 carbon atoms and q represents 0 or a number from 1 to 4, and the bonding of Z may be effected via the oxygen or -(CH2)q - or directly to the phenyl group, the remaining free position being occupied by a hydrogen atom; (b) a 2-hydroxy-benzophenone or -acetophenone group

wherein m represents 0 or 1 and X represents an alkylene group with 1 to 4 carbon atoms optionally substituted by hydroxy groups and R4 represents an optionally substituted phenyl or methyl group, (c) an e-cyano-ss,ss-diphenyl group

wherein p represents an integer from 1 to 4 and P5 and R5 each represent a phenyl group optionally substituted by a C14 alkyl group, (d) a hydroxy-containing benzoic acid ester

wherein one of the two groups P6 or R6 represents a hydroxy group and the other represents hydrogen and R7 represents hydrogen or an alkyl group with 1 to 10 carbon atoms, the linkage being effected via any free unsubstituted position on the phenyl group, (e) an oxalanilide

wherein R8 and Rg, which may be the same or different, represent a hydrogen atom or an alkyl group or alkoxy group with 1 to 8 carbon atoms and r represents 0 or 1, the bonding of being effected via the oxygen or directly to one of the phenyl groups, whilst the other, free position being occupied by hydrogen, (f) p-aminobenzoic acid ester derivatives

wherein R1o and R11 which may be the same or different represent a hydrogen atom or an alkyl group with 1 to 6 carbon atoms; or (g) 6,8-dialkyl-4-oxo-5-chromanyl compounds

wherein R12 and P13 which may be the same or different, represent alkyl groups with 1 to 4 carbon atoms; with the proviso that the group Z should not be bonded via any oxygen belonging to the group if n represents 1.

6. Thermoplastic synthetic mounding compositions as claimed in any one of claims 1 to 5 wherein the monomers containing components which give protection against UV light are radically polymerisable unsaturated compounds selected from: 2-(2'-hydroxy-3'-methacryloylamidomethyl-5'-alkyl)-benzotriazole (wherein alkyl represents methyl or octyl), 2-(2'-hydroxyphenyl )-5-methacryloylamido-benzotriazole, 2-(2'-hyd roxyphenyl )-5-methacryloylamido-methyl benzotriazole, 2-(2'-hydroxy-5-vinylphenyl )-2H-benzotriazole, 2-hydroxy-4-methacryloxybenzophenone, 2-hydroxy-4-acryloxybenzophenone, 2-hydroxy-4-methacryloxy-5-tert.butyl-benzophenone, 2-hydroxy-4-methacryloxy-2',4'-dichlorobenzophenone, 2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone, 4-(allyloxy)-2-hydroxybenzophenone, 2,4-dihydroxy-4'-vinylbenzophenone, vinyl 4-ethyl-a-cyano-ss-phenylcinnamate, 2-cyano-3,3-diphenylacryloxy)alkylene-acrylic acid esters and 2-(acryloyl)oxyethyl-2-cyano-3,3-diphenylacrylate.

7. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein the copolymer P made up of monomers which contain in their molecule components giving protection against UV light (monomers giving protection against UV light) is an acrylic resin.

8. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein the proportion of monomers which contain components giving protection from UV light in the molecular structure is from 0.1 to 20% by weight based on the weight of the copolymer P.

9. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein the copolymer P is prepared form, in addition to monomers which give protection against UV light, esters of acrylic and/or methacrylic acid of formula II

wherein R1 represents a hydrogen atom or methyl group, R14 represents an alkyl group with 1 to 8 carbon atoms or a phenyl group or aralkyl group with 7 - 12 carbon atoms, optionally together with monomers of general formula lil

wherein R;;' represents a hydrogen atom or methyl group, B represents a group - O - or No16, A represents a hydrocarbon bridge with 2 to 6 carbon atoms and 0 represents a hydroxy, methoxy to hexyloxy group or a group - NR16Rl7, whilst P15 represents a hydrogen atom or an alkyl group with 1 to 6 carbon atoms and R76 and R17 represent alkyl groups with 1 to 6 carbon atoms; the sum of the proportions of monomers of general formulae II and III being 70 - 99.9% by weight, based on the total weight of acrylic resin (copolymer P), and the monomers of formula II and ill may replace one another; and in an amount of from 0 to 25% by weight, optionally monomers of general formula IV

wherein R19 represents a nitrile group, a phenyl group optionally substituted by a C14 alkyl group, a heterocyclic group or a -CH2 = CH2 group P20 represents a hydrogen atom or a methyl group; and R18 represents a hydrogen atom or, together with R19, forms an anhydride group

R20 in such a case representing a hydrogen atom; or R19 represents a group

wherein R21 represents an alkyl group with 1 to 6 carbon atoms, with the proviso that in this case P19 and R20 represent hydrogen atoms with the proviso that the Vicat softening temperature (according to DIN 53 460) of the polymer P prepared from monomers I, II and optionally III, and/or IV does not fall below 65"C.

10. Thermoplastic synthetic moulding compositions as claimed in any of the preceding claims wherein the copolymer P comprises for 60 to 99.9% by weight, of methylmethacrylate.

11. Thermoplastic synthetic moulding compositions as claimed in claim 10 wherein the copolymer P comprises from 65 to 90% by weight of methylmethacrylate.

12. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein the proportion ofcomonomers of formula II as defined in claim 9 is from 0 to 30% by weight.

13. Thermoplastic synthetic moulding compositions as claimed in any of claims 1 to 9 wherein the copolymer P comprises 65 - 90% by weight of hydroxyalkylacrylates or methacrylates and 34.9 - 9.9% by weight of heterocyclic vinyl compounds.

14. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein one or more comonomers for formula IV as defined in claim 9 is present in a proportion of from 0 to 25% by weight.

15. Thermoplastic synthetic moulding compositions as claimed in any one of the preceding claims wherein the content of monomers of formula I in the entire moulding composition is not less than 0.1% by weight.

16. Thermoplastic synthetic moulding compositions substantially as hereinbefore described and with reference to the Examples.

17. Optically high-grade mouldings obtained from a thermoplastic synthetic moulding composition as claimed in any of claims 1 to 16.

18. Optically high-grade mouldings as claimed in claim 17 which do not have a turbidity (according to DIN 5036) exceeding 0.5%.

19. Lenses, contact lenses, optical filters, prisms, lattices, mirrors, light conductors, reflectors, optical voltage models and artificial eyes, whenever produced from moulding compositions as claimed in any one of claims 1 to 16.

20. A process for preparing compositions as claimed in any of claims 1 to 16 which comprises copolymerising a mixture of radically polymerisable monomers, at least one of which contains in its molecule a component effective to protect the resulting composition against UV light.

21. A process as claimed in claim 20 substantially as hereinbefore described.

22. A process as claimed in claim 20 substantially as hereinbefore described with reference to any of the Examples.