NO151548B - POLYESTERABLE LIGHT HARDWARE FOR FORMING OR COATING FORMS, AND USING THEM - Google Patents

Description

For the photopolymerization of unsaturated polyester

resins (UP resins), numerous for-

bonds as sensitizers. With acyloins, acyloin-

esters or acyloin ethers as UV sensitisers, a relatively rapid UV curing of UP resins is possible, but the molding materials obtained after curing by high-energy radiation (mercury vapor high-pressure rays) have a yellow tint.

This unfortunate yellowing, which occurs when the molding materials are stored in

darkness recedes, but which again increases when stored in daylight or artificial light, becomes noticeable when covering light wood or firewood. production of light and wave plates in a disruptive manner.

According to BRD-off.skrift 2 104 972 (US patent 3 669 022), yellowing of molding materials made from benzoin ether-containing UP resins can indeed be reduced by compounds of trivalent phosphorus, but not suppressed strongly enough to use UV curing for the above applications.

Also the use of benzyl ketals, which admittedly lead to storable, highly reactive UV-curable UP resins, does not bring any improvement with regard to a more favorable color of the molding materials.

The task of the present invention is to develop light-curable molding, impregnation and coating compounds which, in relation to the state of the art in UV curing, exhibit a significantly greater reaction rate with comparable or better color in the molded bodies obtained.

The task is solved using light-curing molding, impregnation and coating compounds that contain a mixture of

a) at least one ethylenically unsaturated copolymerizable polyester,

b) at least one ethylenically unsaturated copolymerizable monomeric compound,

c) an inhibitor,

d) 0.005-5% by weight, based on the combined weight of a) and b), of a

UV sensitizer, as well as possibly

e) paraffins, thermally decomposable initiators, fillers, reinforcing agents, lubricants, inert solvents, shrinkage-reducing additives and/or further auxiliaries that are applicable to unsaturated polyester masses, and which are characterized in that the UV sensitizer consists of at least one acylphosphine oxide

connection with formula

where R"*" means a straight-chain or branched alkyl residue with 1-6 carbon atoms, a cyclohexyl-, cyclopentyl-, aryl- which may optionally be halogen-, alkyl- or alkyl-substituted, an S- or N-containing 5- or 6- linked heterocyclic residue; ;2 112 ;R has the same meaning as R , whereby R and R can be the same or different, or be an olefin residue with 1-6 carbon atoms, further an aryloxy or an aryl olefin residue, or R <1> and R 2 together with the phosphorus atom may be connected to a ring: R 3 is a straight-chain or branched alkyl radical with 2-18 carbon atoms, a cycloaliphatic radical with 3-10 carbon atoms, a phenyl or naphthyl radical, an S-, O- or N-containing 5- or 6 -membered heterocyclic residue, whereby the residues R 3 may optionally have additional substituents, or is the grouping ;1 2 ;where R and R have the above meaning and X is a phenylene residue or an aliphatic or cycloaliphatic divalent ;residue with 2-6 carbon atoms, and optionally one or more of the residues R<1> to R^ are olefinically unsaturated. ;Form, the impregnation and coating compounds according to the invention are distinguished by high reactivity when irradiated with long-wave UV light (wavelengths from 300 to 500 nm). Advantageous in relation to molding compounds with a content of acyloin derivatives or benzyl ketals as sensitizers is the significantly lower yellowing tendency of the cured molding materials and in particular a faster through-hardening of thick-walled glass fiber-containing molding compounds. This applies particularly favorably to UV curing of laminates which are produced in the hand, winding, centrifugation or fiber spraying process. Correspondingly favorable results are also obtained by UV curing of glass fiber-free, crunchable molding compounds. Preferred UV sensitizers are such acylphosphine oxide compounds having formula I where: R 3 is a cycloalkyl radical, phenyl radical, naphthyl radical, an S-, N- or O-membered 5- or 6-membered heterocyclic radical which at least in both ortho-positions to the carbonyl group contains the substituents A and B bound, whereby A and B are the same or different and mean alkyl, cycloalkyl, aryl, alkoxy, thioalkyl, caralkyloxy, cyano groups or halogen atoms. The feature "in both ortho-positions to the carbonyl group contain the substituents A and B bound" is to be understood so that the substituents A and B are bound to both the carbon atoms that are neighbors to the point of attachment to the carbonyl group, as these carbon atoms can be "substituted." This means, for example, that the α-naphthyl residue at least in the 2,8-positions and the /?-naphthyl residue contain the substituents A and B at least bound in the 1,3-positions. Such UV sensitizers, especially the particularly preferred 2,4,6-trimethylbenzoyldiphenylphosphine oxide, surpass in their reactivity all previously known photoinitiators for unsaturated polyester resins. This high reactivity results in strong heat development during curing of laminates. This made it possible to carry out the curing with radiators with less energy release than previously. One can, for example, forego the use of expensive mercury vapor high-pressure jets and instead use simpler low-pressure lamps, for example ordinary fluorescent tubes. ;Furthermore, with the preferred highly active UV sensitizers, the storage capacity of the sensitized molding, dipping and coating compounds is greatly improved, so that it is possible to produce one-component systems which throughout the storage period possess constant curing activity. For the production of the light-curable molding, impregnation and coating compounds, starting components a) to e) are used, about which the following can be said: a) As unsaturated polyesters for use in connection with the invention, not only the usual unsaturated polycondensation products of preferably dicarboxylic acids and glycols are understood, but also urethane group-containing unsaturated polyesters and unsaturated vinyl ester resins. As unsaturated polyesters, the usual polycondensation products are suitable which consist of polyhydric, especially dihydric carboxylic acids and their esterifiable derivatives, especially their anhydrides, which are ester-like linked to polyhydric, especially dihydric alcohols in an ester-like manner, and possibly additionally contain residues of monohydric carboxylic acids and/or residues of monohydric alcohols and/or residues of hydroxycarboxylic acids, whereby at least part of the residues must have ethylenically unsaturated copolymerisable groups. Suitable as polyhydric, especially dihydric, possibly unsaturated alcohols are the alkanediols and oxalkanediols which exhibit common, especially acyclic, groups, cyclic groups and both types of groups, for example ethylene glycol, propylene glycol-1,2, propanediol-1,3, butylene glycol -1,3, butanediol-1,4-, hexanediol-1,6 , 2 ,2-dimethylpropanediol-1, 3 , diethylene glycol, triethylene glycol, polyethylene glycol, cyclohexanediol-1,2, 2,2-bis-(p-hydroxycyclohexyl )-propane, trimethylolpropane monoallyl ether or butenediol-1,4. Furthermore, mono-, tri- or higher alcohols can be used at the same time, for example ethylhexanol, fatty alcohol, benzyl alcohol, 1,2-di-(allyloxy)-propanol-(3), glycerin, pentaerythritol or trimethylolpropane in minor amounts. The polyhydric, especially dihydric, alcohols are generally reacted in a stoichiometric or nearly stoichiometric amount with polybasic, especially dibasic, carboxylic acids or their condensable derivatives. Suitable carboxylic acids respectively their derivatives are dibasic olefinically unsaturated, preferably α, /3-olefinically unsaturated carboxylic acids, for example maleic acid, fumaric acid, chloromaleic acid, itaconic acid, citraconic acid, methylene glutaric acid and mesaconic acid respectively their esters or preferably their anhydrides. In the polyesters, further other modifying acting dibasic, unsaturated and/or saturated, as well as aromatic carboxylic acids may be condensed, for example succinic acid, glutaric acid, α-methylglutaric acid, adipic acid, sebacic acid, pimelic acid, phthalic anhydride, o-phthalic acid, isophthalic acid , terephthalic acid, dihydrophthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, 3,6-endomethylene-1,2,3,6-tetrahydrophthalic acid, endomethylenetetrachlorophthalic acid or hexachloroendomethylenetetrahydrophthalic acid, further mono-, tri- and higher basic carboxylic acids, for example ethylhexanoic acid, fatty acid, methacrylic acid, propionic acid , benzoic acid, 1,2,4-benzenetricarboxylic acid or 1,2,4,5-benzenetetracarboxylic acid. Maleic acid or its anhydride and fumaric acid are preferably used. As the maximum cross-linking ability available in this type of polyester plays a major role in the performance of the low-shrink polyester, for this area of application the largest part, i.e. 50-100%, of the dicarboxylic acids incorporated in the polyester must be unsaturated. Mixtures of unsaturated polyesters, including those which are only partially soluble in the vinyl monomers (b) and easily crystallize, can also be used with advantage. Such easily crystallising unsaturated polyesters can, for example, be made up of fumaric acid, adipic acid, terephthalic acid, ethylene glycol, butanediol-1,4, hexanediol-1,6 and neopentyl glycol. Unsaturated polyesters with preferably terminal double bonds are also suitable. The unsaturated polyesters have acid numbers of 10-200, preferably 20-85, and average molecular weights of approx. 800-6,000, preferably approx. 1,000-4,000. The amorphous and possibly crystallizable unsaturated polyesters are usually produced by melt condensation or condensation under azeotropic conditions from their starting components according to continuous or discontinuous processes. With regard to the composition of unsaturated polyesters, for example, reference should also be made to the book, to H.V. Boenig: Unsaturated Polyesters: Structure and Properties, Amsterdam, 1964. Instead of unsaturated polyesters - as already mentioned - unsaturated polyesters containing urethane groups can also be used. For this purpose, the above-mentioned unsaturated polyesters are reacted with organic polyisocyanates, preferably aliphatic, cycloaliphatic and especially aromatic diisocyanates, thereby lengthening the unsaturated polyester chain and increasing the molecular weight. For chain extension, it is suitable, for example; with aliphatic diisocyanates, such as 1,4-butane diisocyanate; and 1,6-hexane diisocyanate, cycloaliphatic diisocyanates, e.g. 1,3- and 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and 2,6-cyclohexane diisocyanate as well as the corresponding isomeric mixtures, isophorone diisocyanate and 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate as well as the corresponding isomeric mixtures and preferably aromatic diisocyanates, e.g. 2,4- and 2,6-toluene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate as well as the corresponding isomer mixtures and 1,5-naphthylene diisocyanate . For the production of the urethane group-containing unsaturated polyesters, the starting components are suitably brought into reaction at temperatures of 0-120°C, preferably 15-60°C, in such quantities that the ratio of Zerewitinoff-active hydrogen atoms, preferably bound to OH and COOH groups, because unsaturated polyesters to NCO groups in the polyisocyanates amounts to 1:0.1 to 0.9, preferably 1:0.2 to 0.7. The obtained urethane group-containing unsaturated polyesters have acid numbers of 2-30, preferably 5-20 and average molecular weights of approx. 1,000-10,000, preferably approx. 1,500-6,000. Suitable unsaturated vinyl ester resins for use in connection with the invention possess the characteristic grouping -CO-OCt^CHOH-CI^O- and contain terminally polymerizable unsaturated groups. The vinyl ester resins are prepared by reacting roughly equivalent amounts of a polyepoxy resin and an unsaturated monocarboxylic acid, e.g. 2 equivalents of methacrylic acid with 2 equivalents of a polyepoxy resin. Vinyl ester resins of the aforementioned type are e.g. described in US Patent 3,367,992, according to which dicarboxylic acid half-esters of hydroxy acrylates or methacrylates are reacted with polyepoxy resins. According to US patents 3,066,112 and 3,179,623, vinyl ester resins are obtained from monocarboxylic acid, e.g. acrylic and methacrylic acid. An alternative production method is also mentioned here, according to which a glycidyl methacrylate or acrylate is reacted with the sodium salt of a divalent phenol, e.g. bisphenol A. Vinyl ester resins based on epoxy novolac resins are described in US patent 3 301 743. US patent 3 256 226 discloses vinyl ester resins in which the molecular weight of the polyepoxide is increased by reaction of a dicarboxylic acid with the polyepoxy resin and with acrylic acid. Also considered are modified vinyl ester resins, e.g. such as are specified in BRD-off.skrift 25 34 039 (equivalent to US patent 3 947 422) which contain half-ester groups and are obtained by reacting the second hydroxyl group in the grouping -C0-0CH2-CH0H- CH20- with a dicarboxylic acid anhydride, e.g. the anhydride of maleic acid, citraconic acid, phthalic acid, tetrabromophthalic acid, etc. The light-curable molding, impregnating and coating compounds according to the invention usually contain 10-80% by weight, preferably 15-70% by weight, calculated on the total weight of components (a) and (b) of an unsaturated polyester, a urethane group-containing unsaturated polyester or an unsaturated vinyl ester resin; or mixtures of the aforementioned components (a). (b) As copolymerizable, ethylenically unsaturated monomeric compounds, the allyl and preferably vinyl compounds usually used for the production of unsaturated polyester molding, impregnation and coating compounds are mentioned, such as styrene, substituted styrenes, e.g. p-chlorostyrene or vinyltoluene, esters of acrylic acid and methacrylic acid with alcohols containing 1-18 carbon atoms, i.e. methacrylic acid methyl esters, acrylic acid butyl esters, ethylhexyl acrylate, hydroxypropyl acrylate, dihydrodicyclopentadienyl acrylate, butanediol acrylate and (meth)-acrylic acid amides, allyl esters, e.g. e.g. diallyl phthalate, and vinyl esters, e.g. ethylhexanoic acid vinyl esters, vinyl pivalate, etc. Equally suitable are mixtures of the aforementioned olefinically unsaturated monomers. Particularly suitable as component (b) are styrene, α-methylstyrene, chlorostyrene, vinyltoluene, divinylbenzene and diallyl phthalate. Component (b) is present in the polyester molding, impregnation and coating compounds in general in an amount of 20-90, preferably 30-85, weight%, calculated on the combined weight of components (a) and (b) . (c) The light-curable molding, impregnation and coating compounds according to the invention are stabilized with the usual inhibitors (c). For example, phenolic inhibitors can be mentioned, e.g. hydroquinone, substituted hydroquinones, fuel catechol, tert-butyl fuel catechol, core substituted fuel catechol derivatives; quinones, e.g. benzoquinone, naphthaquinone, chloranil, nitrobenzenes, e.g. m-dinitrobenzene, thiodiphenylamine, N-nitroso compounds, e.g. N-nitrosodiphenylamine and salts of N-nitroso-N-cyclohexylhydroxylamine as well as mixtures thereof. Also suitable as further stabilizers are salts of divalent copper, e.g. copper naphthenates or -octoate, 5 6 7 8~1 (& and quaternary ammonium salts of the structure [NR R ,R RJ X , ;c f. n q ;where R , R , R and R mean an alkyl residue with 1-20 carbon atoms . however, can also be included in the purchase. Suitable are those from the ranks of the oxybenzophenone, the salicylic acid ester and the oxyphenylbenztriazole. ,2, % by weight, calculated on components a) and b). ;d) As UV sensitizers (d), acylphosphine oxide compounds of formula ;come into consideration according to the invention. As acylphosphine oxide compounds, e.g. are mentioned: acylphosphine oxides and acylphosphinic acid esters. With regard to formula --(I) the following details can be mentioned: R1 can be a straight-chain or branched alkyl radical with 1-6 C atoms, e.g. methyl, ethyl, i-propyl, n-propyl, n-butyl, amyl, n-hexyl, cyclopentyl, cyclohexyl, aryl, e.g. phenyl-, naphthyl-, halogen-substituted aryl, e.g. mono- or dichlorophenyl-, alkyl-substituted phenyl-, e.g. methylphenyl-, ethylphenyl-, isopropylphenyl-, tert-butylphenyl-, dimethylphenyl-, alkoxy-substituted aryl-, e.g. methoxyphenyl-, ethoxy-phenyl-, dimethoxyphenyl-, S- or N-containing 5- or 6-membered rings, e.g. thiophenyl-, pyridyl-, ; R 2 can have the same meaning as R 1 and furthermore be an 1-alkyl radical with 1-6 C atoms, e.g. methoxyl, ethoxyl, i-propoxyl, butoxyl, ethoxyethoxyl, aryloxy, e.g. phenoxy-, methylphenoxy-, benzyloxy-, 1 2 ; R can be connected with R to a ring, e.g. in acyl-phosphonic acid-o-phenylene esters. R^ can be an ethyl-, i-propyl-, n-propyl-, n-butyl-, i-butyl-, tert-butyl-, i-amyl-, n-hexyl-, heptyl-, n- octyl-, 2-ethylhexyl-, i-nonyl-, dimethylheptyl-, lauryl-, stearyl-, cyclopropyl-, cyclobutyl-, cyclopentyl-, i-methylcyclopentyl-, cyclohexyl-, 1-methylcyclohexyl-, norbornadienyl-, adamantyl-, phenyl-, methyl-phenyl-, tert.-butylphenyl-, isopropyl-phenyl-, methoxy-phenyl-, i-propoxy-phenyl-, thiomethoxy-phenyl-, α- and /?-naphthyl-, thiophenyl-, pyridyl, Ø-acetoxyethyl - or /3-carboxyethyl residue. ;12 3 ;R , R and R can also contain C-C double bonds which make it possible to polymerize the UV sensitizer into the binder. ; As examples of the UV sensitizers according to the invention can be mentioned: isobutyryl-methylphosphinic acid methyl ester; isobutyryl-phenylphosphinic acid methyl ester; pivaloy-1-phenylphosphinic acid methyl ester; 2-ethylhexanoyl-phenylphosphinic acid methyl ester; 4-Dimethylbenzoyl-phenylphosphinic acid methyl ester p-tert.-Buty1-phenylphosphinic acid isopropyl ester Acryloyl1-phenylphosphinic acid methyl ester ;isobutyry1-diphenylphosphinoxide ;2-ethylhexanoyl-1-diphenylphosphinoxide ;0- toluy1-diphenylphosphinoxide ;p-tert.-butylbenzoyldiphenylphosphinoxide ;3- pyridylcarbonyl-1-diphenylphosphinoxide ;acryloylIdiphenylphosphinoxide ;benzoy1- diphenylphosphine oxide; pivaloyl-1-phenylphosphinic acid vinyl ester; adipoyl-bis-diphenylphosphine oxide. ;Preferably, they find the following application: pivaloyl-1-diphenylphosphinoxide p-toluyl-diphenylphosphinoxide 4-(tert.-buty1)-benzoyl-diphenylphosphinoxide terephthaloyl1-bis-diphenylphosphinoxide 2-methylbenzoyl-diphenylphosphinoxide versatoy1-diphenylphosphinoxide 2-raethyl1-2-ethylhexanoy1-diphenylphosphinoxide 1 - methyl1-cyclohexanoyl-d in phenylphosphinoxide pivaloyl-phenylphosphinic acid methyl ester and pivaloyl-phenylphosphinic acid isopropyl ester. Production of this kind of compounds is successful by reacting acid halides of the formula with phosphines of the formula ;4 ;R = straight-chain or branched C1~ to C8-alkyl, or cycloalkyl1 with 5 or 6 C-atoms; The reaction can be carried out in a solvent, e.g. e.g. a hydrocarbon or a hydrocarbon mixture, e.g. petroleum ether, toluene, cyclohexane, an ether, other common inert organic solvents, or also without solvent at temperatures between -30°C and +110°C, preferably at 10-70°C. The product can be directly crystallized from the solvent, remains after evaporation or distilled in a vacuum. Extraction of the acid halides R CX and the substituted phosphine R 1k 2 POR 4 takes place according to methods known to the person skilled in the art from the literature (e.g. K. Sasse in Houben-Weyl, volume 12/1, p 208-209, G. Thieme-Verlag, Stuttgart). "The method for producing the compounds used according to" the invention can be described, for example, as follows: Suitable phosphines are, for example, methyl dimethoxyphosphine, butyl dimethoxyphosphine, phenyldimethoxyphosphine, toluyldimethoxyphosphine, phenyldiethoxyphosphine, toluyldiethoxyphosphine, phenyl- diisopropoxyphosphine, tolyldiisopropoxyphosphine, phenyldibutoxyphosphine, tolyldibutoxyphosphine or dimethylmethoxyphosphine, dibutylmethoxyphosphine, dimethylbutoxyphosphine, diphenylmethoxyphosphine, diphenylethoxyphosphine, diphenylpropoxyphosphine, diphenylisopropoxyphosphine, diphenylbutoxyphosphine or similar starting materials, which lead to the compounds according to the invention. chlorides and bromides, but acid chlorides are particularly preferred. ;Examples of compounds used according to the invention are particularly the following: ;Especially suitable as UV sensitizers for unsaturated polyester resins are acylphenylphosphinic acid esters or acyldiphenylphosphine oxides whose acyl residue derives from a sec.- or tert.-substituted aliphatic carboxylic acid, e.g. pivalic acid, 1-methylcyclohexanecarboxylic acid, norbornene carboxylic acid, α,Q!-dimethylalkanecarboxylic acid ("Versatic" acid with ;9-13 C atoms), 2-ethylhexanecarboxylic acid, or from a substituted aromatic carboxylic acid, e.g. p-methyl-benzoic acid, o-methylbenzoic acid, 2,4-dimethylbenzoic acid, p-tert-butylbenzoic acid, 2,4,5-trimethylbenzoic acid, p-methoxybenzoic acid or p-thiomethylbenzoic acid. The particularly preferred highly active UV sensitizers are those of the general formula I where R 3 can be: a cycloalkyl, aryl, naphthyl residue, an S-, N- or O-containing 5- or 6-membered heterocyclic residue, e.g. a furyl, pyrrolyl, thienyl, pyranyl or pyridyl residue, which at least in both ortho-positions to the carbonyl group contains the substituents A and B bonded, whereby A and B can be the same or different and means an optionally branched alkyl residue with 1- 6, preferably 1-4, C atoms, e.g. a methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl and tert-butyl residue; further an optionally substituted cycloalkyl residue, e.g. cyclohexyl radical, an optionally substituted aryl radical, e.g. the phenyl or toluyl residue, an alkoxy or thioalkyl residue with 1-6, preferably 1-4, C atoms in the alkyl residue, e.g. methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, methylthio, propylthio, isopropylthio, n-butylthio, sec-butylthio and tert-butylthio; a carboxyl group with 1-6, preferably 1-4, C atoms in the alcohol residue, e.g. the carbo-methoxy, carboethoxy, carbopropoxy, carboisopropoxy, carbobutoxy and carbo-sec.-butoxy group, a cyano group or a halogen atom, e.g. a chlorine, bromine or iodine atom. The acylphosphine oxide compounds which contain R3 bound can for example be visualized by the following structural formulae: where X possibly means additional substituents - i.e. cycloalkyl 1-> aryl, naphthyl or heterocyclic residues and has the meaning of A or B... ;. Examples of such highly reactive UV sensitizers include: 2,6-dimethylbenzoyl 1-phenylphosphinic acid methyl ester. 2,6-dimethoxybenzoyl-1-phenylphosphinic acid methyl ester 2,6-dimethylbenzoyl-diphenylphosphine oxide; 2,6-dimethoxybenzoyl-1-diphenylphosphine oxide . 2,4,6-trimethylberizoy1-phenylphosphinic acid methyl ester 2,4,6-trimethylbenzoyl-diphenylphosphinoxide ;2,3,6-trimethylbenzoyl-diphenylphosphinoxide ;2,4,6-trimethylbenzoyl-tolylphosphinic acid methyl ester 2,4,6-trimethoxybenzoy1-diphenylphosphinoxide 2,6 -dichlorobenzoy1-phenylphosphinic acid ethyl ester 2,6-dichlorobenzoy1-diphenylphosphinoxide ;2-chloro-6-methylthio-benzoyl-diphenylphosphinoxide 2,6-dimethylthio-benzoyl-diphenylphosphinoxide ;2,3,4,6-tetramethylbenzoyl-diphenylphosphinoxide 2-pheny1-6- methylbenzoyl-diphenylphosphine oxide 2,6-dibromobenzoyl-diphenylphosphine oxide ;2,4,6-trimethylbenzoyl-naphthylphosphinic acid ethyl ester 2,6-dichlorobenzoyl-naphthylphosphinic acid ethyl ester 1,3-dimethylphthalene-2-carbonyl-1-diphenylphosphine oxide 2,8-dimethylphthalene-1- carbonyl1-diphenylphosphinoxide ;1,3-dimethoxynaphthalene-2-carbonyl-1-diphenylphosphinoxide 1.3- dichloronaphthalene-2-carbonyl-1-diphenylphosphinoxide 2,4,6-trimethylpyridine-3-carbonyl-diphenylphosphinoxide 2.4- dimethylquinoline-3-carbonyldiphenylphosphinoxide 2,4 -dimethylfuran-3-carbonyl-1-diphenylphosphine oxide; 2,4-dimethoxyfuran-3-carbonyl-1-d iphenylphosphine oxide 2,4,5-trimethyl-thiophene-3-carbonyl-1-phenylphosphinic acid methyl ester 2.4.5-trimethyl-thiophene-3-carbonyl-diphenylphosphine oxide The following compounds are preferably used: 2.4.6-trimethylbenzoyl-diphenylphosphine oxide; 2,6-dimethoxybenzoyl-1-diphenylphosphine oxide ;2,6-dichlorobenzoyl-1-diphenylphosphinoxide;2,-3,5,6-tetramethyl-benzoyl-1-diphenylphosphinoxide;2,4,6-trimethylbenzoyl-phenylphosphinic acid methyl ester. Particularly preferred highly reactive UV sensitizers are acyl-phenylphosphinic acid esters and acyldiphenylphosphinic oxides whose acyl residues are derived from a di-ortho-substituted aromatic carboxylic acid, e.g. 2,4,6-trimethylbenzoic acid, 2,6-dimethoxy-benzoic acid, 2,6-dichlorobenzoic acid or 2,3,5,6-tetramethylbenzoic acid. The acylphosphine oxide compounds which can be used according to the invention are preferably used in amounts of 0.01-3% by weight, calculated on the weight of the unsaturated polyester (a) and ethylenically unsaturated monomeric compounds (b). ;e) As polyester or vinyl ester resin additive components that fall under point (e) come e.g. the following in ;consideration: ;Reinforcing agents, lubricants, inert solvents, shrinkage-reducing additives and/or additional auxiliaries that are applicable to unsaturated polyester masses. ;Paraffins that find use in the light-curable molding, impregnation and coating compounds according to the invention have a melting point of 25-90°C, preferably 45-60°C. A paraffin with a melting point of 46-48°C is particularly preferred. ;Instead of the paraffins, other waxy substances can also be used, e.g. the so-called montan wax known paraffin oxidation products resp. these esters, carnauba wax, long-chain fatty acids, e.g. stearic acid, stearyl stearate, Ceresin etc., are used. To reduce the monomer evaporation and to create a non-sticky surface, the unsaturated molding compounds contain 0.01-5% by weight, preferably 0.05-1% by weight, especially 0.1-0.5% by weight of paraffin, calculated on the combined weight of components a) and b). Suitable thickeners are, for example, those based on alkaline earth oxides, e.g. calcium oxide, calcium hydroxide, magnesium hydroxide and preferably magnesium oxide, as well as mixtures of these oxides or hydroxides. These can also be partially replaced by zinc oxide. ;The content of thickeners in polyester or The vinyl ester molding compounds according to the invention generally amount to 0.5-5, preferably 1-3, % by weight, calculated on the mixture of components a) and b). As additional initiators come next to the acyl-phosphinoxide compounds according to the invention, e.g. the following in consideration: peroxides, e.g. priests, e.g. tert-butyl peroctoate, tert-butyl perpivalate, percarbonates, e.g. bis-(4-tert.-butyl-cyclohexyl)-peroxydicarbonate, di-acyl peroxides, e.g. benzoyl peroxide, dialkylper oxides, e.g. di-tert-butyl peroxide and dicumyl peroxide, hydroperoxides, e.g. cyclohexanone peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide and tert.-butyl hydroperoxide optionally in combination with metal accelerators, e.g. cobalt II salts of ethylhexanoic acid or naphthenic acid; as well as azo compounds, e.g. azo-diisosuccinic dinitrile, tetraphenyl-ethanediol and/or a, a, a', a'-tetrasubstituted dibenzyl compounds, as described for example in Kunststoffe 66^, 693 (1976). Thick laminate constructions with glass fibers and quartz irradiation which are hardened, if, in addition to the acylphosphine oxide compound according to the invention, thermally splitting initiators are used in small quantities, e.g. 0.05-1% by weight, preferably 0.1-0.3% by weight, calculated on the total weight of components a) and b). These initiators are split by the heat generated by the photopolymerisation into radicals so that curing can also take place in deeper layers, which the UV light only attacks insufficiently. Particularly advantageous is also the use of photoinitiator combinations of the acylphosphine oxide compounds described here and known photoinitiators, e.g. aromatic ketones, e.g. benzyl ketals, e.g. benzyl dimethyl ketal, benzoin ethers and esters, e.g. benzoin isopropyl ethers, α-hydroxy-isobutyrophenone, ;diethoxyacetophenone or p-tert,-butyltrichloroacetophenone, aromatic disulphides and naphthalene sulphonyl chlorides. With the aforementioned photoinitiator combinations, it is possible in numerous cases, with comparable lighting times, to achieve a lower residual styrene content of UP resin molding materials than with the acylphosphine oxide compounds alone, even if the curing activity (measured by the temperature rise of the resin sample during lighting) falls. The photoinitiator combinations suitably contain 15-85% by weight, preferably 25-75% by weight, of acylphosphine oxide compounds and 15-85% by weight, preferably 25-75% by weight, of an aromatic ketone, the aromatic weight percentages being calculated on the total weight of the mixture. The combinations are used in amounts of 0.005-7% by weight, preferably 0.01-4% by weight, calculated on the weight of components (a) and (b). ;The curable unsaturated molding, impregnation and coating compounds according to the invention are also added with common fillers, reinforcing substances, lubricants, inert solvents and further auxiliaries. Suitable fillers are, for example, ordinary finely powdered or granular inorganic or organic fillers, which are permeable to long-wave UV light, e.g. aluminum oxide hydrate, quartz sand, finely dispersed silicic acid, asbestos, talc, barium sulphate, light spar (calcium sulphate) and mica. ;As reinforcements come inorganic or inorganic fibers on spokes or flats, possibly of these woven materials, such as mats, e.g. of glass, asbestos, cellulose and synthetic organic high polymers, e.g. polyamide, polyacrylonitrile and polyesters, for example terephthalates. The fillers and reinforcements can be used in amounts of 5-200% by weight, preferably 10-70% by weight, calculated on the total weight of components a) and b). In many cases, a combination of powdery and fibrous fillers is advantageous (e.g. for the manufacture of containers). After the lamination process, the laminate can be covered with a foil that lets UV radiation through, and cured with low-energy UV radiation from fluorescent tubes (e.g. TAK 40 W/05, Philips) over a longer period of time or with Hg vapor high-pressure lamps ( HOK 6, 80 w/cm, Philips) in a very short period of time. As lubricants, e.g. zinc, magnesium and calcium stearate in consideration, as well as polyalkylene ether waxes. ;Furthermore, inert solvents such as ketones, esters, hydrocarbons, in quantities of up to 100% by weight, calculated on the components a), may also be used at the same time. As any shrinkage-reducing additives that can also be used at the same time, e.g. considering thermoplastic polymers, e.g. polystyrene, styrene copolymer, polyvinyl acetate or poly(meth)-acrylates, in amounts from 1 and up to approx. 30% by weight, calculated on components a) + b). ;As radiation sources for curing the moulding, impregnation and coating compounds, e.g. fluorescent tubes, high-pressure mercury jets as well as direct sunlight are mentioned. ;The moulding, impregnation and coating compounds according to the invention can be used in many technical areas. They are e.g. suitable as: ;1. Fine-layer resins; The fine layers, which are only approx. 0.5 mm thick, serves to protect the underlying laminate with fine hydrolysis-sensitive glass fibers. These resins must satisfy high requirements for curing activity, and the molding materials must show only slight yellowing. The transparent thin layers are applied to a mold by spraying or coating, then gelled by UV radiation or hardened and then applied to the glass fiber-containing mold compound. ;2. Fibre-reinforced moldings ;a) Light boards ;These boards stand out for the construction sector with a high ;transparency and little yellowing. For the production of flat, longitudinal or transversely corrugated light plates, machines are used that work continuously. With the light-stabilized UP resins, glass silk mats are dipped between cover foils, vented and finally made to harden by cold curing. When using the acylphosphine oxide initiators described here, curing can also be carried out more rationally by UV radiation from Hg vapor high-pressure jets or also so-called blue light lamps (see, for example, regarding light plate production: P.H. Seiden, "Glasfaserverstårkte Kunststoffe", p. 610, Springer-Verlag Berlin-Heidelberg-New York, 1967). ;b) Discontinuous processes for the production of fibre-reinforced, especially glass-fibre-reinforced, moldings; which come into question for UV curing, are: ;Procedure for application by hand, fiber spraying, centrifugation and winding process (description of the processes, see P.H. Seiden, " Fiberglass-reinforced plastics"). ;Usable items that can be produced according to these methods are e.g. boots, container boards (chipboard or joiner boards that are coated on both sides with glass fiber reinforced plastic), pipes, containers. c) UP-resin-finish layer for fiberglass-containing moldings (GRP) and paper laminates. ;The surface quality of GRP and paper laminates can be significantly improved by applying a fine layer. The following advantages can thereby be achieved: ;1. GRP laminates, e.g. corrugated sheets: ;a) Longer gloss retention when stored in the open air, and thereby less dirt build-up. b) Slight lowering of the transparency when stored in the open air, by protecting the glass/resin interface. ;2. Paper laminates based on unsaturated polyester, urea or melamine resins: ;a) increase in surface gloss. ;b) Surfaces that are more grip-insensitive to those made of melamine resins. c) Due to the high transparency of the UP thin layer, an optical impression is created as with a surface coated with a clear lacquer. ;The thin layer itself must be produced on a carrier (e.g. foil) before the laminate production. For this purpose, a 20-200 µm thick UP resin layer is drawn on a separating foil, which is then UV-cured. Complete curing takes place later when the laminate is cured. The fine layer production according to known methods has the following disadvantages: a) When curing with organic peroxides in heat, high styrene losses are recorded, so that there is a danger of under-curing. ;b) When curing with peroxide and an accelerator in heat, it is true that styrene losses can be reduced, but the disadvantage has been that there is a shorter processing time (30-60 minutes) and that the molding material has its own color due to of the accelerator (Co salts). ;c) UV curing with known photoinitiators leads to yellow-like fine layers; the yellowing is further intensified by storage in the open air. With the molding compounds according to the invention, the defects described in the other methods do not occur. On the contrary, rapid curing with UV light gives almost colorless fine layers that neither turn yellow in daylight nor artificial light. ; 3. Embeddings ; For use with casting resins, which can be used for embeddings of e.g. electronic parts, the new sensitizers are ideally suited. When embedding light-impermeable objects, uniform lighting must be ensured from all sides. The parts and percentages mentioned in the examples mean, unless otherwise stated, weight. Volume units relate to units such as liters to kg. The examples and comparative examples were carried out with the following unsaturated polyester resins: Resin A is a 65% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, o-phthalic acid, ethylene glycol and propylene glycol-1.2 in the molar ratio 1:2 :2.4:0.70. The unsaturated polyester has an acid number of 50. Resin B is a 67% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, tetrahydrophthalic acid and diethylene glycol in the molar ratio 1 : 0.5 : 1.5. The unsaturated polyester has an acid number of 43. Resin C is a 66% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, o-phthalic acid and propylene glycol-1.2 in the molar ratio 1 : 0.5 : 1.5. The unsaturated polyester has an acid value of 50. Resin D is a 65% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, isophthalic acid, propylene glycol-1,2 and diethylene glycol in the molar ratio 1 : 0.67 : 0.72 : 1. The unsaturated polyester has an acid number of 26. Resin E is a 65% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of fumaric acid, adipic acid, neopentyl glycol and propylene glycol-1.2 in the molar ratio 1 : 1 : 1.7 : 0.35. The unsaturated polyester has an acid number of 17. Resin F is a mixture of 55% resin A and 45% of a 0.01% hydroquinone stabilized styrenic solution of an unsaturated polyester of maleic acid, adipic acid, propylene glycol-1,2 and diethylene glycol in the molar ratio 1 : 0.5 : 0.55 : 1 which exhibits an acid number of 30. Resin G is a 65% styrenic solution stabilized with 0.012% hydroquinone of an unsaturated polyester of maleic acid, o-phthalic acid, propylene glycol-1, 2 and diethylene glycol in the molar ratio 1 : 0.25 : 1 : 0.25. The unsaturated polyester has an acid number of 43. Resin H is a 65% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, o-phthalic acid and propylene glycol-1.2 in the molar ratio 1:1:2. The unsaturated polyester has an acid number of 52. Resin J is a 65% styrenic solution stabilized with 0.01% hydroquinone of an unsaturated polyester of maleic acid, o-phthalic acid and propylene glycol-1.2 in the molar ratio 1:2:3. The unsaturated polyester has an acid number of 30. ;Resin K Commercial vinyl ester resin ("Derakane" 411-45) ;As UV sensitizers, the following compounds belonging to the state of the art were used for comparison examples: ;I benzyldimethyl ketal ;II benzoin methyl ether ;III benzoin isopropyl ether ;IV methylolbenzoin methyl ether ;The examples according to the invention were carried out with the following acylphosphine oxides and acylphosphinic acid esters: ;X pivaloyl-1-diphenylphosphine oxide ;XI p-toluyl-diphenylphosphine oxide ;XII 4-(tert-butyl)-benzoyl-diphenylphosphine oxide ;XIII terephthaloyl-1-bis-diphenylphosphine oxide ;XIV 2-methylbenzoy1-diphenylphosphine oxide ;XV versatoyl-diphenylphosphine oxide ;XVI 2-methyl-1-2-ethylhexanoy1-diphenylphosphine oxide ;XVII 1-methyl-cyclohexanoy1-diphenylphosphine oxide ;XVIII pivaloy 1-phenylphosphinic acid methyl ester ;XIX pivaloy 1-phenylphosphinic acid isopropyl ester ;As highly active UV sensitizers acyl-phosphinoxides used: XX 2,4,6-trimethylbenzoyl-diphenylphosphinoxide XXI 2,6-dimethoxybenzoyl-diphenylpho sphinoxide ; XXII 2 ,6-dichlorobenzoy 1-diphenyl phosphinoxide ;\ XXIII 2,3,5,6-tetramethylbenzoyl-diphenylphosphinoxide ;XXIV 2,4,6-trimethylbenzoyl-phenylphosphinic acid methyl ester. ;The acylphosphine oxide compounds used according to the invention were prepared in the following way: ;Pivaloyl-diphenylphosphine oxide X ;To a mixture of 1350 parts by volume of petroleum ether (boiling range 40-70°C), 180 parts by volume of N,N-diethylaniline and 67 parts by volume methanol is added while stirring at 0°C 225 parts of diphenylchlorophosphine, dissolved in 220 parts by volume of petroleum ether. The mixture is then stirred for a further 2 hours at room temperature. After cooling to approx. +5°C, the secreted amine hydrochloride is sucked off and the filtrate first distilled at 10-20 Torr, to remove all low-boiling material. The methoxydiphenyl phosphine is then fractionally distilled at 0.1-1'Torr. Kp. Q 5 120-124°C. Yield: 175 parts (80% calculated on diphenylchlorophosphine). To 36.2 parts of pivaloyl chloride, 64.8 parts of methoxy-diphenylphosphine are added dropwise while stirring at 30-60°C. After the addition is complete, the whole is allowed to react for a further 30 minutes, cooled to 0-10°C and the precipitated product is recrystallized from cyclohexane. ;Yield: 69.5 parts of pivaloyldiphenylphosphine oxide (81% of theory). ; 110-112°C, NMR (CDCl 3 , 6), 1.33 (s), 7.4-8.0 (m); Analysis C 17 H 19 O 3 P (286): C 71.33 H 6.64 P 10.84 ; found: C 70.0 H 6.5 P 11.0 ;p-toluyl-diphenylphosphine oxide XI ;To 77 parts of toluyl acid chloride are added 108 parts of methoxydiphenylphosphine (as described above), dissolved in 200 parts by volume of toluene. It is then heated for 60 minutes to 50°C, cooled, the precipitate of toluyldiphenylphosphine oxide is suctioned off and recrystallized from cyclohexane. ;Yield: 117 parts (73% of theory), m.p. 105°C; NMR (CDCl 3 ,&): 2.35 (s); 7.2 bis 8 (m) ;Analysis C20H17<0>2<P> (320) calculated C 75.00 H 5.31 P 9.69 ;found C 75.3 H 5.8 P 9.3 ;4 -(tert.-butyl)-benzoy1-diphenylphosphine oxide XII ; Analogous to X, 41.3 parts of p-tert.-butylbenzoic acid chloride are reacted with 45.4 parts of methoxydiphenylphosphine, dissolved in 20 parts of toluene, at 50°C for 90 minutes. After evaporating the solvent on a rotary evaporator, mari carries out recrystallization from cyclohexane. ;Yield: 63 parts (83% of theory). Temp. 136°C; NMR (CDCl 3 , &): 1.3 (s); 7.3-8.1 (m); 8.5 (d). ;Analysis C23<H2>3<0>2P (362) calculated C 76.24 H 6.35 P 8.56 ;found C 76.0 H 6.5 P 8.7 ;Terephthalo1-bis-diphenylphosphine oxide XIII ;Analog with XI, from 52 parts of terephthalic acid dichloride, dissolved in 200 parts of toluene, and 108 parts of methoxydiphenylphosphine, 46 parts of terephthaloyl-bis-diphenyl-phosphine oxide are prepared. (Yield: 35% of theory), m.p. 205°C. ;NMR (CDC13, S): 6.8 to 8.2 (m) ;-Analysis C32H2404<P>2 (<5>34) calculated C 71.91 H 4.49 P 11.61 found C 71.8 H 4.8 P 11.0 ;2-methylbenzoyl-diphenylphosphine oxide XIV ;Analogous to XI is prepared from 77 parts of 2-methyl-benzoic acid chloride and 108 parts of methoxydiphenylphosphine 134 parts of 2-methylbenzoyl-diphenylphosphine oxide. (Yield 84% of theory), m.p. 107°C. ;NMR (CDC13>6): 2.5 (s); 7.2 to 8 (m); 8.8 (m) ;Analysis C20H1702P (320) calculated C 75.00 H 5.31 P 9.69 ;found C 74.7 H 5.4 P 9.5 ;Versatoyl diphenylphosphine oxide XV ;Analogously at X one drops at 50°C 43.2 parts methoxy-diphenylphosphine to 35.3 parts 2,2-dimethyl-heptane-carboxylic acid chloride ("Versatic" acid chloride). Stir for 3 hours at 50°C, cool to 15°C and stir the mixture into a slurry of 60 g of silica gel in 350 ml of toluene, and stir for a further 1 hour under ice-cooling. Suction is then carried out, and the solvent is distilled off under reduced pressure. Versatoyl diphenylphosphine oxide remains as a viscous oil. ;Yield: 62 parts (90% of theory) ;NMR (CDC 13 , &): 0.4 to 2.3 (m); 7.2 - 8.1 (m) ;Analysis <C>2]<H>27<0>2<P> (342) calculated C 73.68 H 7.89 P 9.06 ;found C 73.6 H 8.1 P 8.6 ;2-methyl1-2-ethylhexanoyl-1-diphenylphosphine oxide XVI ;Analogous to X is obtained from 88 parts of 2-methyl-2-ethylhexanoic acid chloride and 108 parts of methoxydiphenylphosphine 165 parts of 2-methyl-3- ethyl-hexanoyl-diphenylphosphine oxide in the form of an oily crude product. Column chromatography on silica gel 60 (eluent: toluene/ether 3:1) gives the product as a slightly yellowish oil. Yield: 154 parts (90% of theory). ;NMR (CDCl 3 , 6): 1.2 (s); 0.5 to 2.2 (m); 7.3 to 8.1 (m) ;Analysis <C>21H27°2P ^342^ calculated C 73.68 H 7.89 P 9.06 ;found C 73.9 H 8.1 P 9.4 ;1 -methyl-1-cyclohexanoyl-diphenylphosphine oxide XVII; Analogous to XI is obtained from 80 parts of 1-methyl-1-cyclohexane-carboxylic acid chloride and 108 parts of methoxydiphenylphosphine without solvent 100 parts of 1-methyl-Tcyclohexanoyl-diphenylphosphine oxide in the form of an oily crude product which is purified by chromatography on silica gel (solvent toluene). ;Yield: 42 parts (26% of theory), m.p. 80°C. ;NMR (CDCl 3 , ): 14 (s); 1.1 to 1.6 (m); 2.1 to 2.4 (m); ;7.3 to 8.0 (m) ;Analysis ^ 2<^ L23°2P (<3>26) calculated C 73.62 H 7.06 P 9.51 ;found C 73.3 H7.l P9, 6 ;Pivaloy1-phenylphosphinic acid methyl ester XVIII ;To a mixture of 1000 parts by volume of toluene, 421 parts by volume of N,N-diethylaniline and 100 parts by volume of methanol, 214 parts of phenyldichlorophosphine are added at 0°C. The mixture is then stirred for a further 1 hour at room temperature, the precipitate of amine hydrochloride is suctioned off and fractionated. The dimethoxyphenylphosphine distills at 46-50°C/0.2-0.3 mm. ;Yield: 190 parts (93% of theory) ;To 78.7 parts of pivaloyl chloride is added dropwise at 15°C ;110.5 parts of dimethoxyphenylphosphine. It is then heated for 30 minutes to 50°C and the reaction mixture is then distilled. Pivaloylphenylphosphinic acid methyl ester decomposes at 104-107°c/0.3 mm. Yield: 101.3 parts (65% of theory). NMR (CDCl 3 , ): 1.3 (s); 3.75 (d); 7.4 to 8 (m). ;Pivaloy 1-phenylphosphinic acid isopropyl ester XIX ;To a mixture of 600 parts by volume of petroleum ether, 263 ;parts of N,N-diethylaniline and 120 parts of isopropanol, 143 parts of phenyldichlorophosphine are dripped over the course of 1 hour at 0°C. The mixture is then stirred for a further 1 hour at room temperature and then distilled after working up as described in example 1. The diisopropoxy-phenylphosphine distils at 68-72°C/0.3 mm. Yield: 126 parts (69% of theory). 158 parts of diisopropoxyphenylphosphine are added slowly with good stirring at 50-60°C to 84 parts of pivalic acid chloride. Stirring continues for 2 hours and fractionation in vacuum. Pivaloy 1-phenylphosphinic acid isopropyl ester distills at 119-121°C/0.5 mm. Yield: 112 parts (60% of theory). ;NMR (CDCl 3 , o) 125 (s); 1.33 (h); 4.5 (m); 7.3 to 8 (m) ;Analysis: <C>14<H>2i°3<P> (268): calculated C 62.68 H 7.84 P 11.57 ;found C 63.0 H 8, 0 P 11,4 ;2,4,6-trimethylbenzoyl-diphenylphosphine oxide XX ;In a stirring apparatus with reflux cooler and dropping funnel, add slowly at 50-55°c 648 parts of methoxydiphenyl-1-phosphine to 547.5 parts of 2,4,6- trimethylbenzoyl chloride. The mixture is stirred for a further 4-5 hours at 50°C, the contents of the flask are dissolved at 30°C in ether and petroleum ether is added until paleness begins. On cooling, 910 parts (87% of theory) of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide crystallize. Melting point: 80-81°C, slightly yellow crystals. ;2,6-dimethoxybenzoy1-diphenylphosphine oxide XXI ;In an apparatus as described for the preparation of initiator XX, 20 parts of 2,6-dimethoxybenzoyl chloride are suspended in 20 parts by volume of toluene, and to this mixture is added dropwise at 50-55°C with stirring 21.6 shares methoxydiphenylphosphine. The mixture is stirred for a further 3 hours at 50°C and then recrystallized directly from toluene. 32 parts of yellowish crystals are obtained, mp: 124-126°C. ;Further highly active initiators, which were synthesized in an analogous manner, are listed in table 2. ;UV curing activity ;For measuring the curing activity, the temperature course in the unsaturated polyester resin (UF resin) resp. vinyl ester resin recorded under the UV illumination. For this purpose, a thermosensor coated with a layer of wax, which was connected to a temperature recorder (Tastotherm Script 3 N, standard sensor T 300 from Deutschen Gulton GmbH), was immersed in a white-tin lid which was filled with 10 g of UP resin and had a diameter of 5 cm (layer thickness for the UP resin was 4.8 mm). To avoid heat loss during the UV illumination, the lid was embedded in polyurethane resin foam. A UV field of 5 fluorescent tubes (TLAK 40 W/05, Philips) next to each other served as a radiation source. The distance between the beams/UP resin surface was 8.5 cm. From the recorded temperature/time curves, the curing time RZ^^o^^ and the maximum achieved curing temperature T^ were taken as characteristic values for the curing activity. The curing time refers to the period of time in which the sample's temperature rises from 25 C to T^^g ; Example 1 ; Preparations of resin C with 0.2% of various sensitizers were cured with UV light in the manner described above. A comparison of the curing activity (table 3) shows that with initiator X according to the invention, the fastest curing is possible. Next follows benzyldimethyl ketal (I) as the most favorable of the previously known and partly commercially available products. In further comparison experiments, the work was therefore predominantly done with this initiator X. Example 2 ; Example 3 ; For the production of UV-stabilized molding materials, e.g. for thin layers or light plates, UP resins containing UV absorbers are used. These additives can influence the UV curing speed. The following experiment shows how strong this effect is. ;Preparations of resin A, commercially available UV absorbers (0.1%) and in each case 0.2% sensitizer I resp. X was cured with fluorescent tubes after the reactivity measurement described. The results in table 5 show that, as expected, the preparations containing UV absorbers react more slowly than the non-UV stabilized ones. At the same time, however, it is early that the preparations according to the invention harden much faster than those with sensitizer I. ;Example 4 ;In order to investigate the influence of mineral filler additions on the UV curing speed, resin A, which was sensitized with 0.2% initiator, was X, UV-cured in the presence of different fillers (radiation source: Fluorescent tube; TUV 40 W/05, Philips). The temperature/time curve recorded according to the described measurement method gave the values for the curing time and the maximum curing temperature T^^g*

The results from these investigations appear in table 6.

Example 5

The curing activity of resin A preparations according to the invention was also determined with the raw long-wave radiation of a lamp doped with sodium hydride (HRI, 2000 W, "Power-Star"). In relation to the described method, the lamp distance to the substrate surface was 60 cm.

Example 6

Production of fiberglass-reinforced UP-form compounds.

a) Preparations were made a<y> resin A with 0.15% benzyl dimethyl ketal (batch i) resp. with 0.15% pivaloyl-diphenylphosphine oxide (batch 2) glass fiber mat laminates (glass fiber content was 25%) with a thickness of 5 and 10 mm and these were irradiated with UV light (fluorescent tube TUV 40 W/05, Philips) at a distance of 11 cm. After specific illumination times, the Barcol hardness (Barcol-Impressor, Model 934-1) was measured on the laminate side opposite the light source. The results are summarized in table 8.

b) For curing with a mercury vapor high-pressure jet, mat laminates with 9 mm were produced from batches 1 and 2

thickness (glass fiber content 39%) on polyester foil and turned on a turntable at a distance of 35 cm under the UV rays. The effective lighting time was 3 minutes, the laminate thickness 9 mm.

When determining the Barcol hardness after cooling the molding materials, with the radiator on the opposite side, it also turned out here that the initiator

pivaloyl diphenylphosphine oxide X was superior to benzyl dimethyl ketal (I). The Barcol hardness at batch 2 was 50 and at batch 1 zero.

Example 7

UV curing of blocks of UP resin A

a) In forms of glass plates (16 x 11 x 11 cm), whose inner side surfaces were covered with a yellow foil, in each

illuminated 1800 g of resin A - catalyzed firstly with benzyldimethylketal (I; 0.05%) and secondly with pivaloyldiphenylphosphine oxide (X, 0.05%) - with fluorescent tube (TUV 40 W/0.5, Philips) . Hereby, the experimental device was used that the UV light (from a field with 10 lamps next to each other, 87 x 49 cm) could penetrate the resin preparations from below through the glass bottom plates. The lamp/form distance was 17 cm and the layer thickness to be cured, 9 cm.

These experiments clearly showed that the sensitizer system. used in the invention enables a significantly faster cure than benzyl dimethyl ketal. While with benzyldimethylketal after 9 hours of illumination a yellow molding material is obtained whose upper layer is still liquid, the result after 1.5 hours of illumination of the preparation according to the invention is a bright, thoroughly cured molding material.

b) In further experiments, the cured layer thickness of different resin preparations was measured as a function of the irradiation time. For this purpose they were sensitized

mixtures of resin A and photoinitiators in each case illuminated from above in a crystallization dish (diameter 9 cm) whose side walls were glued with UV-impermeable

paper ("Tesakrepp"), and lighting-painted fluorescent tube (TUV 40 W/05, Philips). The distance from the resin surface to the radiation source was 11 cm.

A narrow, vertical viewing slit in the wall adhesion made it possible to observe the course of the hardening in a deeper layer in a measurable way. The boundary between the cured and uncured resin layer was easy to see due to the difference in refractive index. The results are summarized in table 9.

While only 18 of the 62 mm was cured with benzyldimethyl ketal within 80 minutes, the result was med-pivaloyldiphenyl-phosphinoxide (X) 62 mm, i.e. the entire block. By adding tert-butyl peroctoate, the curing time was shortened to 30

minutes.

Example 8

To evaluate the light yellowing of UP resin moldings, 4.8 mm thick rondels (diameter 5 cm) of different resins, which were sensitized with 0.2% UV initiator, were cured under fluorescent lighting (TUV 40 W/05, Philips) and then exposed to radiation from a UV field with 10 fluorescent tubes of the aforementioned type for 40 minutes at room temperature. The distance between the radiation source and the disc surface was 11 cm.

The yellowness was assessed on the basis of the Yellowness Index

according to ASTM D 1925-67. The measurement is made with instrument DMC 25 from Fa. Zeiss in transparency.

From the results in table 10, it is clear that the solids of the preparations according to the invention are in all cases less yellowed than those of known preparations (content of sensitizers I-IV).

Example 9

In order to be sure that by UV curing of peroxide-containing molding compounds less colored products are also obtained with the sensitizers according to the invention, preparations of resin A, tert.-butyl peroctoate and the sensitizers I, II and X were illuminated for 25 minutes in a UV-permeable form (5.3 x 3.4 x 1.45 cm) with a fluorescent tube (TUV 40 W/05, Philips) from a distance of 15 cm. The cooled blocks were then exposed to the light from the same UV rays for 1 hour at room temperature.

The molding material with sensitizer X has the lowest Yellowness Index and is thus the least yellowed (table 11).

Example 10

Manufacturing. of a thin layer that can be pressed onto paper laminates or GRP surfaces.

For example, an approx. 100 ^ura thick film with a preparation of resin A, 0.5% sensitizer X and

1% benzoyl peroxide on a separator and this was carried

under a mercury vapor high-pressure loop at 1 m/min.

The lamp/foil distance was 25 cm. The thus hardened fine layer was hot pressed onto a paper laminate or GRP surface. The fine layer was not yellowed.

In the following examples 11-17, the particularly preferred highly reactive UV sensitizers were used.

Example 11

Preparations of UP resins A, C, G, B and vinyl ester resin K with 0.2% of various sensitizers were cured with UV light in the manner described above.

A comparison of the curing activity (Table 12) shows that the fastest cures are possible with the initiators XX to XXIV. Pivaloyl-diphenylphosphine oxide (X) does achieve the activity of 2,6-dichlorobenzoyl-diphenylphosphine oxide (XXII), but its activity decreases with time at storage in UP resins.

Example 12

Preparations of the UP resins A resp. B and various UV initiators were stored in closed vessels at 60°C, and then the curing activity at room temperature was measured as described in Example 11.

In table 13, the measurement results before and after storage are compiled. They show very clearly that the initiators XX-XXIV have kept their activity constant under the experimental conditions. Storage trials over a longer period of time at room temperature also point in the same direction (table 14).

Example 13

Preparations of the UP resins A resp. B and various UV initiators were stored in the dark in closed vessels at room temperature, and the curing activity was measured from time to time according to the method described in Example 11. The results in table 14 show that with initiator XX storage-resistant UV-curable UP resins are obtained.

Example 14

To evaluate light yellowing of UP resin moldings, 4.8 mm thick rondels (diameter 5 cm) of the UP resins A, H and J, which were sensitized with different UV initiators, were cured by lighting with fluorescent tubes (TL AK 40 W/ 05, Philips) and then exposed to radiation from the same light sources for 60 or 120 min. at room temperature (5 fluorescent tubes next to each other). The radiation source/rondello surface distance was 8.5 cm.

The yellowness was assessed on the basis of the Yellowness Index

according to ASTM D 1925-67. The measurement was made with instrument DMC 25 from Fa. Zeiss in transparency.

From the results in table 15, it is clear that the molding materials of the preparations according to the invention are in all cases less yellowed than those of known preparations with a content of benzyldimethyl ketal (I).

Example 15

UV curing of UP resin molding compounds

a) 60 parts of the preparations of UP resin G with 0.1% UV initiator XX or with 0.1% benzyl dimethyl ketal (I)

was mixed with 40 parts of filler, "Martinal" BM 2 (Al-jO^-BE^O, Fa. Martinswerke , Bergheim/Er f t) and with 1.5% magnesium oxide "light" (manufacturer: Fa. Merck, Darmstadt) (calculated on UP resin). With these mixtures, several layers of glass fiber mats ("Vetrotex" textile-glass mat M 123-40-450) with dimensions 10 x 12 cm were soaked, thickened between polyester foils for 3 days at room temperature and finally hardened by lighting with fluorescent tubes (TL AK 40 W/05), whereby the temperature course in form-?. , the mass was monitored using a thermocouple. The distance between beams (5 fluorescent tubes next to each other) and the molding surface was 8 cm. The exposure time corresponded to the time in which the molding compound reached the maximum curing temperature.

After cooling the molding materials, the Barcol hardness (Impressor 935) was measured on the bottom and top side.

The results from table 16 make it possible to clearly recognize the advantages of the preparation according to the invention with UV initiator XX. With 3 layers of fiberglass mats - corresponding to a layer thickness of 3.8-4.5 mm - an illumination time of 5 minutes is sufficient. 15 sec., at a layer thickness of 6.6-7.2 mm (= 7 layers of fiberglass mats) with approx. 13 min. in order to achieve sufficient heating of the molding compound. In the case of molding compound based on benzyl dimethyl ketal (i), despite doubling the lighting time, no through-hardening of the laminate is achieved with 7 layers of glass fiber mats. b) Crunchy, fiberglass-free UP resin molding compounds were produced by 3-day thickening of preparations of UP resin G, filler A1203.3H20 ("Martinal" BM 2, Martinswerke, Bergheim/Erft), 1.5% magnesium oxide "light" (calculated on UP resin) and UV initiator XX resp. benzyl dimethyl ketal (I)

(in each case 0.1% calculated on UP resin). The weight ratio UP resin:filler was 60:40.

In each case, a 2 cm thick layer was exposed in a tin lid to 35 minutes of radiation from a fluorescent tube (TL AK 40 W/05, Philips), whereby the temperature course was followed using a thermocouple inserted 1 cm into the molding compound. The distance between the beams and the surface of the mold was 6 cm. After cooling, the uncured lower molding compound layer was removed mechanically and the Barcol hardness (Impressor 935) of the thus newly acquired surface was measured after cleaning.

With the molding compound according to the invention, a 12.6 mm thick layer was hardened, with the known molding compound with a content of benzyl dimethyl ketal (I) only a 7 mm thick layer was hardened (see table 17).

Example 16

Preparations of UP resin A and the UV sensitizers XX and I as well as mixtures of these were irradiated in a layer thickness of 10 mm with a fluorescent tube (TL-AK 40 W/05, Philips). The UP resin samples were in white tin lids

with a diameter of 5 cm, which to prevent large heat losses stood on a cork board (5 mm thick). The distance between fluorescent tube and resin surface was 8 cm. After lighting and cooling, a rod was sawn out of the molding materials in each case, whereby the total layer thickness was noted, and whose residual styrene content was measured titrimetrically in accordance with DIN 16 945. The results obtained are summarized in table 18. They show that the residual styrene contents in the molding material samples are lower with the sensitizer combination XX and I than with the sensitizers XX and I alone.

Example 17

The light curing of unsaturated polyester resins can also be carried out in two stages with the photoinitiators used in the invention, whereby in the first stage a flexible, storage-resistant semi-finished product is created after a short exposure time, which can be shaped, cut and, for example, punched out for the production of buttons. With renewed illumination in the second step, the final curing finally takes place: A 0.1% solution of 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide (XX) in resin A was irradiated for 1 min. with fluorescent tubes (TL-AK 40 w/05, Philips) in a 2 mm thick layer between two polyester foils. The beam/resin surface distance was 10 cm.

A flexible semi-finished product was obtained which could be easily cut with a sharp knife and easily shaped by hand. Barcol hardness on both sides was 0 (Barcol-Impressor 935).

After 24 hours of storage at room temperature with no light outside, the unchanged flexible semi-finished product was cured by renewed illumination with the fluorescent tubes (illumination time: 15 min.). The Barcol hardness of the molding material after cooling to room temperature was 87-89, and it had become hard.

To avoid a greater loss of heat, the semi-finished product lay

under the illumination on a foam plastic plate.

Claims (7)

1. Light-curable molding, impregnating and coating compositions containing a mixture of: a) at least one ethylenically unsaturated copolymerizable polyester, b) at least one ethylenically unsaturated copolymerizable monomeric compound, c) an inhibitor, d) 0.005-5% by weight, based on the total weight of a) and b), of a UV sensitiser, as well as possibly e) paraffins, thermally decomposable initiators, fillers, reinforcing agents, lubricants, inert solvents, shrinkage-reducing additives and/or additional auxiliaries that are applicable to unsaturated polyester masses, characterized in that the UV sensitizer consists of at least one acyfostin oxide compound of formula whereby R<1> means a straight-chain or branched alkyl residue with 1-6 carbon atoms, a cyclohexyl-, cyclopentyl-, aryl- which may optionally be halogen-, alkyl- or alkoxy-substituted, an S- or N-containing 5- or 6-membered heterocyclic residue; 2 112 R has the same meaning as R , whereby R and R can be the same or different, or be an aldehyde residue with 1-6 carbon atoms, furthermore, an aryloxy or an arylalcolic acid residue, or R 1 and R 2 together with the phosphorus atom can be connected to form a ring; R<3> is a straight-chain or branched alkyl radical with 2-18 carbon atoms, a cycloaliphatic radical with 3-10 carbon atoms, a phenyl or naphthyl radical, an S-, O- or N-containing 5- or 6-membered heterocyclic radical, whereby the residues R<3> can possibly have further substituents, or the grouping is 1 2 where R and R have the meaning given above and X is a phenylene radical or an aliphatic or cycloaliphatic divalent radical with 2-6 carbon atoms, and 1 3 optionally one or more of the residues R to R are olefinically unsaturated. 2. Light-curable molding, impregnation and coating compounds as specified in claim 1, characterized in that the UV sensitizer consists of an acylphosphine oxide compound of formula I, whereby R and R have the above meaning and R is a tert.-aliphatic residue. 3. Light-curable masses as stated in claim 1, characterized in that the UV sensitizer consists of a 1 2 acylphosphine oxide compound of formula I, whereby R and R have the above meaning and R 3 is a cycloalkyl residue, phenyl residue, naphthyl residue, an S-, N - or 0-containing 5- or 6-membered heterocyclic residue, which at least in both ortho-positions to the carbonyl group contains the substituents A and B bonded, whereby A and B are the same or different and mean alkyl-, cycloalkyl-, aryl-, alkoxy -, thioalkyl, carbolicoxy, cyano groups or halogen atoms. 4. Light-curable masses as stated in claim 1, characterized in that the UV sensitizer consists of an acylphosphine oxide compound of formula I, whereby R 1 and R 2 have the above meaning and R 3 is a 2,4,6-trimethylpheyl residue. 5. Light-curable masses as stated in claim 1, characterized in that as UV sensitizers they contain acylphosphine oxide compounds of formula I in combination with aromatic ketones, aromatic disulphides or naphthalene sulfonyl chlorides in the weight ratio 85:15 to 15:85. 6. Light-curable masses as specified in claim 5, characterized in that benzyl ketals, benzoin ethers or benzoin esters are used in the soya aromatic ketones. 7. Use of light-curable moulding, impregnation and coating compounds according to claim 1, for the production of molded bodies and coatings.