AU624196B2 - Liquid, radiation-cured coating composition for glass surfaces - Google Patents

Description

OP I DATE 26/06/90 APPLN. ID 45121 89 AOJP DATE 26/07/90 PCT NUMBER PCI/EP89/01382 INTERNATIONALE -XN M EL& N^ Kli P JLIC NAg l)EM VERTKRAG UI3ER DIE INTERNATIONALE ZUSAMM E* UF E BI ES PATENTWE"NS (PCT) (51) Intemiationale Patentklassifikation 5 (11) Inerna oale orrentlichungsnummer: WO 90/06289 C03C 25/02 Al (43) Intemationales (21) Internationales Aktenzeichen: PCT/EP89/0 1382 Bestimmungsstaaten: AT (europiiisches Patent), AU, BE (europitisches Patent), BR, CH (europdisches Patent), (22) Internationales Anmeldedatum: DE (europilisches Patent), DK, ES (europ~isches Pa- 17. November 1989 (17.11.89) tent), Fl, FR (europtiisches Patent), GB (europiiisches Patent), IT (europaisches Patent), JP, KR, LU (europisches Patent), NL (europ~isches Patent), NO, SE (euro- Priorititsdaten: p~isches Patent), SU, US.

P 3840 644.6 2. Dezember 1988 (02.12.88) DE Yeroffentlicht (71) Anmelder (ftir alle Bestimrungsstaaten ausser US): BASF AM internationalem Recherchenberich.

LACKE FARBEN AKTIENGESELLSCHAFT [DE/ DEJ; Max-Winkelmann-Strage 80, D-4400 Monster

(DE).

(72) Erfinder; und Erfinder/Anmelder (nur ffir US) :SCHUNCK, Sieohan [Dkl*/DE]; Gleueler Strak~ 123, D-5000 K61n 41 (DE).

(74) Anwalt: LEIFERT, Elmar;, BASF Lacke Farben AG, Patenltabteilung, Postfach 61 23, D-4400 MOP.5ter, (DE).

(54)Title: LIQUID, RADIATION-CURED COATING COMPOSITION FOR GLASS SURFACES (54) Bezeichnung: FLOSSIGE, STRAHLENHARTBARE OBERZUGSMASSE FOR DIE BESCHICHTUNG. VON GLAS- OBEXFLXCH EN (57) Abstract The invention concerns a liquid, radiation-cured coating composition for glass surfacis, containing 56-89 14 by wt. of at least one diethylene-unsaturated polyurethane which-may contain carbamide groups; 10,30 Va by wt. of at least one ethyleneunsaturated monomer; 0.5-8 by wt. of at least one photoinitiator;1 0.05-6 by wt. N-p-aminoethyl-y-aminopropyltrimethoxysilane, y-aminopropyltrimethoxysilane, N-methyl-y-aminopropyltrimethoxysilane or triamino-modified propyltrimethoxysilane, whereby the sum of components A-D is 100 by wt, and all the percentages by weight are expressed relative to the coating composition. This coating material is used to coat glass surfaces, in, particular glass optical fibres, and is characterized by its good adherence characteristics, even in damp conditions.

(57) Zusamm~nassung Gegenstand der vorliegende-a irindung ist eine notssiype, strahlenhiabare Oberzugsmasse, die 56 bis 89 Gew.-0% mindestens eines gegebenenfalls 1-arstoffgruppen enthaltende i diethylenisch ung ,esitttigten Polyurethans, 10 bis 30 Gew.-% mindens eiries ethylenisch ungesttigten Monomers; k),5 bis 81 Gew.-% nvindestens eines Photoinitikitors;, 0,05 bis 6 Gew.-% N-P-Aninoethyl-y-aminopropyltrimethoxysilan, Y-Andncprj !ytdimethoxysilan, N -Methyl-y-aminopropyitrimethoxysi- Ian oder triaminomodifiziertes Propyltrimethoxysilar, enthlllt, wobei- die Simnme der Komponenten bis jeweils 100 Gew, betr'1gt Lind sich alle Gew.-%-Angaben auf die 0berzugsmasse b(ezithen. Diese COberzugsmittel werden for die Beschichtung von Glasoberf1ichen, insbesondere optischen Glasfasern, eingesett Lind zeichner 5ich durch eine gute Haftung auch bei Feuchtigkeitsbelastung ams, PAT 88 181 4 Nov. 1988 '3830z) BASF Lacke und Farben AG Liquid, radiation-curable coating composition for coating glass surfaces The present invention relates to a liquid, radiation-curable coating composition for coating glass surfaces and containing A) 56 to 89% by weight, based on the coating composition, of at least one diethylenically unsaturated polyurethane optionally containing urea groups, B) 10 to 30% by weight, based on the coating composition, of at least one ethylenically unsaturated monomer, C) 0.5 to 8% by weight, based on the coating composition, of at least one photoinitiator, and D) 0.05 to 6% by weight, based on the coating composition, of an alkoxysilane, the sum of components to in each case being 100% by weight.

The present invention also relates to a process for coating glass surfaces,, in particular optical glass fibers, using these radiation-curable coating compositionsa, Optical glass fibers have achieved constantly increasing importance in the sector of communications as optical waveguide fibers. For this application, it is absolutely necessary to protect the glass surface against moisture and abrasion. The glass fibers are therefore provided, immediately after production, with a protecting paint coat.

V 2 Thus, it is known, for example, from EP-B-114,982 to provide glass fibers firstly with a buffer coating (primer) which is elastic, but not very hard and not very tough, and then to apply a radiation-curable top coat which has high hardness and toughness. The two-layered construction is intended to ensure good protection of the optical fibers under mechanical load, even at low temperatures. As the top coat, radiation- ,arable coating compositions based on a polyurethane containing diethylenic end groups, a diethylenically unsaturated ester of a diglycidyl ether of a bisphenol, and a monoethylenically unsaturated monomer, the glass transition temperature of the homopolymer prepared from this monomer being above 0 C, are employed in EP-B-114,982.

However, glass fiber coatings of this type have the considerable disadvantage of only poor adhesion to the glass surface. In particular on exposure to moisture, this adhesion is further impaired, under certain circumstances even so greatly that full loss of adhesion on the glass surface occurs. The problem of poor adhesion of the coating compositions to the glass surface is known. In order to improve the adhesion, organosilanes, as adhesion promoters, are therefore frequently added to the coating compositions. Thus, it is known, for example, from EP-B-33,043 to add organosilanes, as adhesion promoters, to radiation-curable coating agents based on vinyl monomers and reactive polymers (not polyurethanes), it being essential to the invention that either the vinyl monomers or the polymers have a thiirane ring. Examples 7 16 In v 3 mentioned of suitable compounds are y-aminopropyltriethoxysilane, N,p-aminoethyl-7-aminopropyltrimehoxysilane and 7-glycidyloxypropyltrimethoxysilane. There is no mention in this application of the loss in adhesion of the glass fiber coatings on exposure to moisture.

It is also known, from Japanese Patent 45,138/85 of 8 October 1985 (corresponds to Japanese Preliminary Published Specification 42,244/80 of 25 March 1980), to employ organosilanes as adhesion promoters in radiationcurable glass fiber coating agents. The film-forming components employed are polymers having azide groups.

7 -methacryloxypropyltrimethoxysilanes, 7-aminopropyltrimethoxysilane and y-glycidyloxypropyltrimethoxysilane are mentioned as suitable silanes. However, it is essential to Japanese Patent 45,138 that the azide groups are incorporated into the polymers in order to increase the curing rate. This publication too does not therefore mention the problem of the effect of moisture on the adhesion of the glass fiber coating.

Finally, EP-A-149,741 discloses liquid, radiation-curable glass fiber coating agents which contain, besides a radiation-curable, polyethylenically unsaturated polymeric compound, 0.5 to based on the coating composition, of a polyalkoxysilane. Polyalkoxysilanes which carry an organic substituent which carries a single active amino or mercaptyl hydrogen atom which is able to react with the ethylenically unsaturated bonds in a Michael addition are suitable. An example mentioned of r suitable silanes is y-mercaptopropyltrimethoxysilane.

Sii: -4- According to the teaching of EP-A-149,741, it if only possible to improve the adhesion even on exposure to moisture by using silanes of this type. By contrast, compounds usually employed as adhesion promoters, such as, for example, aminopropyltriethoxysilane and N-3-(Nvinylbenzylaminopropyl)trimethoxysilane prove, according to EP-A-149,741, to be unsuitable for improving the adhesion on exposure to moisture.

The present invention therefore had the object of providing radiation-curable coating compositions for coating glass surfaces, in particular optical glass fibers, in which the resultant coating, after exposure to moisture, had only slight loss in adhesion, or none at all, compared with the corresponding freshly prepared coating examined immediately after curing.

The object underlying the invention is achieved by a liquid, radiation-curable coating composition for coating glass surfaces which contains A) 56 to 89% by weight, based on the coating composition, of at least one diethylenically unsaturated polyurethane optionally containing urea groups, B) 10 to 30% by weight, based on the coating composition, of at least one ethylenically unsaturated monomer, C) 0.5 to 8% by weight, based on the coating composition, of at least one photoinihator (sic), D) 0.05 to 6% by weight, based on the coating composition, of an alkoxysilane, 1%/Ipx the sum of components to in each case being 100% by weight.

In the coating composition, component is N-p-aminoethyl-y-aminopropyltrimethoxysilane or -y-aminopropyltrimethoxysilane or N-methyl-y-aminopropyltrimethoxysilane or triamino-modified propyltrimethoxysilane.

In view of the large number of organosilicon compounds known as adhesion promoters, it was surprising and not forseeable that the use of N-p-aminoethyl-yaminopropyltrimethoxysilane, 7-aminopropyltrimethoxysilane, N-methyl- 7 -aminopropyltrimethoxysilane and triamino-modified propyltrimethoxysilane (for example DYNASYLAO adhesion promoters, type "TRIAMO", commercial product from Dynamit-Nobel Chemie) impairs the adhesion of radiation-curable coating agents based on unsaturated polyurethanes on glass surfaces on exposure to moisture only insignificantly or not at all, while considerable impairment in adhesion occurs on exposure to moisture when other known adhesion promoters, such as, for example, y-glycidyloxytrimethoxysileie and the monohydrepchloride of N-p- (N-vinylbenzylamino)ethyl-y-aminopropyltrimethoxysilane, are used.

The coating composition according to the invantion is described below in greater detail: The diethylenically unsaturated polyurethanes (A) employed as the film-f'Orming component can be obtained by reacting a diisocyanate or polyisocyante with a chain extender from the group comprising diols/polyols and/or

IA

-6 diamines/polyamines and/or dithiols/polythiols and/or alkanolamines and subsequently reacting the free isocyanate groups which remain with at least one hydroxyalkyl acrylate or hydroxyalkyl ester of other ethylenically unsaturated carboxylic acids.

The amounts of chain extenders, diisocyante or polyisocyanate and hydroxyalkyl esters of an ethylenically unsaturated carboxylic acid are selected here so that the equivalent ratio between the NCO groups and the reactive groups of the chain extender (hydroxyl, amino or mercaptyl groups) is between 3:1 and 1:2, and is preferably 2:1, and the OH groups of the hydroxyalkyl esters of ethylenically unsaturated carboxylic acids are present in a stoichiometric amount relative to the stillfree isocyanate groups of the prepolymer made from isocyanate and chain extender.

In addition, it is possible to prepare the polyurethanes by firstly reacting some of the isocyanate groups of a diisocyanate or polyisocyanate with at least one hydroxyalkyl ester of an ethylenically unsaturated carboxylic acid, and subsequently reacting the remaining isocyanate groups with a chain extender. In this case too, the amounts of chain extender, isocyanate and hydroxyalkyl esters of unsaturated carboxylic acids are selected so that the equivalent ratio between the NCO groups and the reactive groups of the c in extender is between 3:1 and 1:2, and is preferably 2:1, and the V. 77" L equivalent ratio between the remaining NCO groups and the

"I"

-7- OH groups of the hydroxyalkyl ester is 1:1.

It is of course possible to use all intermediate forms of these two processes. For example, some of the isocyanate groups of a diisocyanate can firstly be reacted with a diol, more of the isocyanate groups can subsequently be reacted with the hydroxyalkyl ester of an ethylenically unsaturated carboxylic acid, and the remaining isocyanate groups can then be reacted with a diamine.

These various preparation processes for polyurethanes are known for example, EP-A-204,161) and do not therefore require more detailed description.

Isocyanates which are suitable for preparation of the polyurethanes are aromatic, aliphatic and cycloaliphatic diisocyanates and polyisocyanates, such as, for example, 2,4- and 2,6-toluylene diisocyanates and mixtures thereof, 4,4'-diFhenylmethane diisocyanate, mphenylene diisocyanate, p-phenylene diisocyanate, 4,4'diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 1,4naphthalene diisocyanate, 4,4'-toluidine diisocyanate, xylylene diisocyanate and substituted aromatic systems, such as, for example dianisidine diisocyanates, 4,4'diphenyl ether diisocyanates or clorodiphenylene (sic) diisocyanates, and higher-functional aromatic isocyanates, such as, for example, 1,3,5-tr.iisocvanatobenzene, 4, 41,41 triisocyanattriphenylmethane (sic), 2,4,6-triisocyanatotoluene and 4,4' -diphenyldimethytmethan 2,2' 5 isocyanate; cycloaliphatic isocyainates, ruch as, for example, 1,3-cyclopentane diisocyanate- 1,4-cyclohexane -8diisocyanate, 1, 2-cyc lohexane diisocyanate, 44 -methylene bis(cyclohexyl isocyanate) and isophorone diisocyanate; aliphatic isocyanates, such as, for example, tri-&3':thylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyihexamethylene 1, 6-diisocyanate and tris-hexamethylene triisocyanate, and the diisocyanates derived from dimeric fatty acids described in EP-A-204,161, column 4, lines 42 to 49.

2, 4- and 2, 6 -toluylene diisocyanate, 4, 4' -diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone di.isocyanate and 4,4'-methylene bis-(cyclohexyl isocyanate) are preferably employed.

Examples of suitable diols and polyols are, for example, ethylene glycol, propylene 1,2-glycol and 1,3glycol, butanediols, pentanodiols, neopentyl glycol, hexanediols, 2-methylpentane-.1, 5-diol, 2-ethyltsutane-1, 4diol, dimethylolcyclohexane, glyce.rol, tr,-Met hylol1ethane, trimethylolipropane and trinoiethylolbutane, arythritol, mesuarythritol, arabitol, adolaitol, xylitol, mannitol, sorbitol, dulcitol, hexanetriol, (poly)-pentaerythritol; further monoethers, such as diethylene glycol and dipropylene glycol, and polyethers, the adducts of the polyols mentioned and alkylene oxides. Examples of alkylene oxides they (sic) are suitable for polyaddition to these polyols to form polyethers are ethylene oxide, propylene oxide, butylene oxide and styrene oxide. These polyaddition products are generally called polyethers having terminal hydroxyl groups. They may be linear or branched.

9 9 Examples of polyethers of this type are polyoxyethylene glycols having a molecular weight of from 200 to 4,000, polyoxypropylene glycols having a molecular weight of from 200 to 4,000, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, polyoxynonamethylene glycol, polyoxydecamethylene glycol, polyoxydodecamethylene glycol and mixtures thereof. Other types of polyoxyalkylene glycol ethers may also be used. Suitable polyether polyols are also those which are obtained by reacting polyols of this type, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol and mixtures thereof; glycerol trimethylolethane, trimethylolpropane 1,2,6-hexanetriol, dipentaerythritol, tripentaerythritol, polypentaerythritol, methyl glycosides and sucrose, with alkylene oxides, such as ethylene oxide, propylene oxide or mixtures thereof.

Examples of suitable polyether diols are also the polymerization products of tetrahydrofuran or o2 butylene oxide. It is also possible to use polyester polyols, preferably polyester diols, which cati be prepared, for example, by reacting the abovementioned glycols with dicarboxylic acids, such as, for example, phthalic acid, isophthalic acid, hexahydrophthalic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, glutaric acid, tetrachlorophthalic acid and hexachloroheptanedicarboxylic acid. Instead of these acids, it is also possible to use their anhydrides if they exist.

It is also possible to use polycapolactone diols rr I~ 10 and triols. These products are obtained, for example, by reacting an e-caprolactone with a diol. Such products are described in US Patent 3,169,945.

The polylactone polyols obtained by this reaction are distinguished by the presence of a terminal hydroxyl gz p and by recurring polyester units derived from the lactone. These recurring molecular units may conform to the formula 0 C (CHR) n

CH

2 0 in which n is preferably 4 to 6, and the substituent is hydrogen, an alkyl radical, a cycloalkyl radical or an alkoxy radical, no substituent containing more than 12 carbon atoms and the total number of carbon atoms in the substituent in the lactone ring not exceeding 12.

The lactone used as starting material can be any lactone or any combination of lactones, but this lactone should contain at least 6 carbon atoms in the ring, for example 6 to 8 carbon atoms, and at least 2 hydrogen substituents should be present on the carbon atom bonded to the oxygen group of the ring. The lactone used as 0 starting material may be represented by the general formula below.

o in which n and R are as already defined above. The lactones which are preferred in the invention for the preparation of the polyester diols are caprolactones in which n has the value 4. The most-prv lactone is substitued c-caprolactone in which n has the value 4 and all R substituents are hydrogen. This lactone is particularly preferred since it is available in large amounts and gives coatings having excellent properties. In addition, vrarious other lactones can be used individually or in combination.

Examples of aliphatic diols which are suitable for the reaction with the lactone are the diols already mentioned above for the reaction with the carboxylic acids.

Examples of suitable amines are ethylenediamine, tri- 1 tetra-, penta- hexa-y hepta-, nona-, deca- and dodecamethylenediamine, 2,2,4- and 2,4, 4-trimethylhexamethylenediamine, propylenediami~o and the corresponding polyalkylenediamines, such as, for example, polypropylenediamine, polyether diamines having a molcecular weight of from 200 to 4,000, for example po lyoxyl ethyl ent-diamin (sic), polyoxypropylenediamine, polyoxytetramethylectj,.amine, 1,3- and 1,4-butylenediamine, isophoronediami Ine., 1,2- and 1, 4-diaminocyqohexane, 4,4' -diaminodicyclohexylmethaaie, bis- (3-methyl-4-aminocyclohexyl )methane, 2,2bis (4-aminocyclohexyl)propape, 4, 7-dioxadecane-i, diamin-, 4,9-dioxadodecane-1, 12-diamine, 7-methyl-4,-10dioxatridecane-1, 13-diamine (sic), nitrilotris(ethaneamine) (sic), ethanolamine, propanolamine, N-(2-aminoet) eyl)no, polyether polyamiines, bis- 3-aminopropyl) methylamine, 3 -amino- I- (methylamino) propane, 3-amino-i- 12 12 (cyclohexylamino) propane, N-(2-hydroxyethyl)ethylenediamine, tris-(2-aminoethyl)amine, and polyamines of the formula H 2

N-(R

2

-NH),R,-NH

2 n is an integer between 1 and 6, preferably 1-3. R, and R 2 are identical or different alkylene groups or cycloalkylene groups or alkylene groups containing ether groups, in each case having 2-6, preferably 2-4, C atoms. Examples of polyalkylenepolyamines of this type are diethylenetriamine, triethylenetetra-ine, tetraethylenepentamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine and dibutylenetriamine.

Chain extenders which can be employed are also dithiols and polythiols, such as, for example, dithioethylene glycol, 1,2- and 1,3-propanedithiol, butanecd.thiols, pentanedithiols, hiexanedithiols and the other S-H analogous compounds of the diols and polyols mentioned.

Suitable for introducing the ethylenically uni iturated groups into the polyurethane are hydroxyalkyl esters of ethylenically unsaturated carboxylic acids, such as, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyamyl acrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate and the corresponding hydroxyalkyl esters of methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, and isocrotonic acid.

The unsaturated polyurethane is employed in the coating compositions in an amount of from 56 to 89% by weight, based on the coating composition.

6- MEO lii L 13 Besides the polyurethane just described, the coating agent according to the invention also contains to 30% by weight, based or the coating composition, of at least one ethylenically unsaturated monomer Examples of suitable monomers are ethoxyethoxyethyl acrylate, Nvinylpyrrolidone, phenoxyethyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl acrylate, butoxyethyl acrylate, isobornyl acrylate, dimethylacrylamide and dicyclopentil acrylate. Also suitable are diacrylates and polyacrylates, such as, for example, butanediol diacrylate, trimethylolpropane diacrylate and triacrylate, pentaerythritol diacrylate and the long-chain linear diacrylates having a molecular weight of from 400 to 4,000, preferably 600 to 2,500, which are described in EP-A-250,631. For example, the two acrylate groups may be separated by a polyoxybutylene structure. It is also possible to employ 1,12-dodecyl diacrylate and the product of the reaction of 2 moles of acrylic acid with one mole of a dimeric fatty alcohol, which generally has 36 C atoms.

Mixtures of the monomers just described are also suitable.

Preferably employed ace N-vinylpyrrolidone, phenoxyethyl acrylate, isobornyl acrylate and mixtures of these monomers.

The photoinitiator employed in the coating compositions according to the invention in an amount of from 0.5 to 8% by weight, preferably 2 to 5% by weight, based on the coating composition, varies with the Ln oe^admrcftyachl hc eeal a 2034kaos Mitrso ooes utdsrbdaeas suitale.U -T K 1 1 -14 radiation employed to cure the coating agents (UV radiation, electron radiation, visible light). The coating compositions according to the invention are preferably cured by means of UV radiation. In this case, ketonebased photoinitators are usually employed, for example acetophenone, benzophenone, diethoxyacetophenone, mchloroacetophenone, propiophenone, benzoin, benzil, benzil dimethyl ketal, anthraquinone, thixanthone (sic) and thioxanthone derivatives, and mixtures of different photoinitiators.

Together with the photoinitiators mentioned, various amines, for example diethylamine and triethanolamine, can be employed, if appropriate, in amounts of up to 4% by weight, based on the coating composition, and act as synergists, As the component essential to the invention, the coating compositions contain 0.05 to 6% by weight, based on the coating composition, of N, p-aminoethyl-y-aminopropyltrimethoxysilane, y-aminopropyltrimethoxysilane, Nmethyl-y-aminopropyltrimethoxysilane or triamino-modified propyltrimethoxysilane (for example DYNASYLAN* adhesion proaoters, "type TRIAMO", commercial product from Dynamit Nob'al Chemie). These alkoxysilanes are commercially available products and therefore need not be described in greater detail. Preferred coating agenits are obtained by employing either 0.5 to 2% by weight, based on the coating composition, of N,p-aminoethyl-y-aminopropyltrimethoxysilans or 2 to 4% by weight, based on the coating composition, of 7-aminopropyltrimethoxysilane or 3 to S 76 M by weight, based on the coating composition, of N-methyl- ,7-aminopropyltrimethoxysilane or 4 to 6% by weight, based on the coating composition, of triamino-modified propyltrimethoxysilane (for example DYNASYLAN adhesion promoters, "type TRIAMO", commercial product from Dynamit Nobel Chemie) as component The coating compositions according to the invention may, if appropriate, additionally contain customary auxiliaries and additives in customary amounts, preferably 0 05 to 10% by weight, based on the coating composition. Examples of substances of this type are flow agents and plasticizers. The coating compositions may be applied to the glass surface by means of known methods of application, such as, for example, spraying, rolling, flowcoating, dipping, knife coating or brushing.

The paint films are cured by means of radiation, preferably by means of UV radiation. The equipment and conditions for these methods of curing are known from the literature for example, R. Holmes, U.V. and E.B.

Curing Formulations for Printing Inks, Coatings and Paints, SITA Technology, Academic Press, London, United Kingdom 1984) and require no further description.

The present invention also relates to a process for coating a glass surface, in which a radiation-curable coating composition is applied which contains A) 56 to 89% by weight, based on the coating composition, of at least one diethylenically unsaturated S Spolyurethane optionally containing urea groups, 16 B) 10 to 30% by weight, based on the coating composition, of at least one ethylenically unsaturated monomer, C) 0.5 to 8% by weight, based on the coating composition, of at least one photoinitiator, and D) 0.05 to 6% by weight, based on the coating composition, of an alkoxysilane, the sum of components to in each case being 100% by weight, and II.) the coating composition is cured by means of UV or electron radiation.

In the process, the coating composition contains, as component .N--aminoethyl-y-aminopropyltrimethoxysilane or y-aminopropyltrimethoxysilane or N-methyl-yaminopropyltrimethoxysilane or triamino-modified propyltrimethoxysilane.

For a more detailed description of the coating agent employed in the process according to the invention and of the way in which this process is carried out, reference is made to pages 5 to 13 of this description.

The process according to the invention is particularly suitable for coating optical glass fibers. In particular when optical glass fibers are used as optical waveguides, it is important that the coating compositions applied to protect the surface have good adhesion to the glass surface even on exposure to moisture. Losses in adhesion of the coating after exposure to moisture which cannot be avoided when glass fibers are used as optical waveguides (for example glass fibers are 4FM 17 exposed to the air at coupling stations), result in paint damage on the glass fiber surface. This surface, which is then unprotected, can very easily be damaged, for example by grains of dust, which results in a loss in optical properties. The process according to the invention and the coating compositions according to the invention, in particular, make it possible, however, to avoid these disadvantages and to provide coatings having very good adhesion, even after exposure to moisture.

The coating compositions according to the invention can be applied to the glass fibers either in the form of a single coat or as the primer of a two-coat system. Suitable top coats in the case of the two-coat system are described, for example, in EP-B-114,982.

The invention is described in greater detail in the examples below. All parts and percentages are by weight, unless expressly stated otherwise.

Example 1 (comparison) A radiation-curable coating composition comprising 75.8 parts of unsaturated polyurethane, 9,2 parts of trimethylolpropane triacrylate, 12 parts of phenoxyethyl acrylate, 0.5 part of benzil dhiethyl ketal and 2.5 parts of benzophenone is prepared by known methods for example, EP-B-114,982), by firstly reacting 4 moles of 4,4'-methylene bis-(cyclohexyl isocyanate) with 2 moles of polyoxypropylene glycol (molecular weight 1,000) in the presence of trimethylolpropane triacrylate and phenoxyethyl acrylate. This intermediate obtained is reacted with 2 moles of 2-hydroxyethyl acrylate and then L i 18 with 1 mole of polyoxypropylenediamine (molecular weight 230). The photoinitiators are then added to the mixture.

Thoroughly purified (in particular grease-free) glass plates (width x length 98 x 151 mm) are masked at the edge with Tesakrepp* adhesive tape No. 4432 (width 19 mm), and the coating composition is applied by knife coating (dry film thickness 180 im).

The curing is carried out using a UV irradiation apparatus equipped with two Hg medium-pressure lamps each with a lamp power of 80 W/cm, at a belt speed of m/minute, in 2 passes at half power 40 W/cm).

The incident dose here is 0.08 J/cm 2 (measured using the dosimeter, UVICURE, system EIT from Eltosch).

The adhesion is tested immediately thereafter as follows: Carefully detach the beginning of the foil from the glass using a razor blade.

Attach a wire hook to the detached part of the foil using adhesive tape.

Hook in a spring balance and remove at right angles at the most constant rate possible.

Read off the removal force required in g from the measurement scale.

The adhesion test is evaluated by averaging the values obtained from a double determination and checking the reproducibility of good high) adhesion values by several repetitions.

The result of the adhesion test is shown in Table 19 Besides this adhesion test, which woo carried out, a roll peeling test in accordance with DIN 55 289 is also possible, but was not carried out.

In order to test the adhesion after exposure to moisture, the glass plates were additionally stored for 12 hours after curing in suitable climatic chambers having a defined atmospheric humidity of 90% relative atmospheric humidity (corresponding to DIN 50005) at room temperature Immediately after completion of exposure, the removal test using the spring balance was carried out analogously to the adhesion test immediately after irradiation.

In this case too, the adhesion test was evaluated by taking the average of a double determination. In the case of good (0 (sic) high) adhesion values, at least two repeat measurements were carried out in order to check the reproducibility.

The result of this test is likewise shown in Table 1.

The test carried out for adhesion to window glass gives good, meaningful results as a laboratory method.

This method is also carried out at glass fiber manufacturers since it gives values close to those in practice which agree very well with the adhesion values on optical I glass fibers (typical fiber thickness 125 pm).

Example 2 (comparison) A radiation-curable coating agent based on the l? unsaturated polyurethane is prepared analogously to 4e (f 3 Comparison Example 1. In contrast to Comparison Example 1, the coating agent additionally contains 2% by weight, based on the total composition, of y-glycidyloxypropyltrimethoxysilane.

Analogously to Comparison Example 1, this coating agent is applied to glass plates by means of a knife coater (dry film thickness 180 um) and cured using a mercury medium-pressure vapor lamp (dose likewise 0.08 j (sic)/cm 2 The adhesion of the coating is measured, as described in Comparison Example 1, immediately after curing of the coating agent and after storage for 12 hours at 90% relative atmospheric humidity at room temperature. The results are shown in Table 1.

Examples 3 and 4 (comparison) Glass coatings are prepared analogously to Example 2, but with the difference that the 2% by weight, based on the total composition, of 7-glycidyloxypropyltrimethoxysilane are now replaced by 2% by weight of 3butenyltriethoxysilane (Example 3) or 2% by weight of the monohydrochloride of N-p-(N-vinylbenzylamino )ethylaminopropyltrimnethoxysilane (formula 3 Si (CH 2 3 NH (CH) 2 NH-CH- -CH CH 2 HCl (Example in each case based on the total composition.

The results of the adhesion test are shown in Table 1.

Examples 5-7 Glass coatings are prepared analogously to Example 2, but with the difference that the 2% by weight of r-glycidyloxypropyltrimethoxysilane are now replaced IT (C3)S Cj H( )2NHCz o C C toluene and 4,4 -diphenyldimethylmethane 2,2' isocyanate; cycloaliphatic isocyanates, such as, for L example, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane 0 N I S- 21 by 1 (Example 5) or 2 (Example 6) or 3 (Example 7) by weight of N- -aminoethyl-y-aminopropyltrimethoxysilane, in each case based on the total composition.

The results of the adhesion test are shown in Table 1.

Example (sic) 8-9 Glass coatings are prepared analogously to Example 2, but with the difference that the 2% by weight of 7-glycidyloxypropyltrimethoxysilane are now replaced by 2 (Example 8) or 4 (Example 9) by weight of Nmethyl-y-aminopropyltrimethoxysilane, in each case based on the toal composition.

The results of the adhesion test are shown in Table I.

Examples 10-11 Glass coatings are prepared analogously to Example 2, but with the difference that the 2% by weight of y-glycidyloxypropyltrimethoxysilane are now replaced by 2% byw eight of y-aminopropyltrimethoxysilane (Example 10) or 2% by weight of triamino-modified propyltrimethoxsilane (sic) (DYNASYLANO adhesion promoters, type "TRIAMO", commercial product from Dynamit-Nobel Chemie), in each case based on the total composition.

The results of the adhesion test are shown in Table i.

-V 0

A

22 Table Example Adhesion promoter (D) Amount of Adhesion 11,y after curing weight) (ka) 2 1 -Glycidyl]oxypropyltrimethoxysilane 3 1 -1htenyltri ethoxys ilane 4 Monohydrochloride of N-P-CNvinylbenzylamino) ethyl-l-aminopropyltrimnethoxys ilane N-P-Aminoethyl-7-aminopropyltrimethoxysilone 6 N-fl-Amino ethy- 7- aminopropyltri methoxysilane 7 N-P-Aminoethyl-'l-aninopropyltrimethoxysilane 8 N-Methyl-'y-axinopropyltrimethoxysi lane 9 N-Mthyl-'l-aminopropyltrimethoxya ilane 'y-Azinopropyltrimethoxysi lane 11 Triamino-modified propyltrimethoxysilane C 'TRIA!'U') 1,000-1,100 2 1,000-1,100 2 9(u0-1,000 750-1, 00' 1, 000'-i,100 1,000-1, 100 900-1, 000 850- 950 1, 200-1, 400 1,000-1, 150 1, 000-1, 100 Adhesion after 12 hours at 90% rh.

(kfA) 50- 100 150 900-1,000 900-1,000 800- 900 850- 950 1, 000-1, 100 750- 850 500 Examples 1-11 show that only very low loss adhesion, if any, occurs after exposure to moisture due to the addition of N-,-aminoethyl-y-aininopropyltrimeth,oxysilane, N-methyl-l-aminopropyltrimethoxysilane, Iaminopropyltrimethoxysilane and triamino-modif ied propyltrimethoxysilane (DYNASYLANO adhesion promoters, type "TRIAMO"1, from Dynamit Nobel Chemie), while considerable loss in adhesion is observed on exposure to moisture when other, known silane adhesion promoters, such as, for example, -1-glycidyloxypropyltzimethoxysilane, 3-butenyltriethoxysilane and the monohydrochloride of N-P-(Nvinylbenzylamino ethyl -I-aminopropyltrimethoxys ilafte, are added.

Claims (1)

146. :0. 0. 0 S0 0 00 0 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A liquid, radiation-curable coating composition for coating glass surfaces comprising A) 56 to 89% by weight, based on the total weight of the coating composition, of at least one diethylenically unsaturated polyurethane, B) 10 to 30% by weight, based on the total weight of the coating composition, of at least one ethylenically unsaturated monomer, C) 0.5 to 8% by weight, based on the total weight of the coating composition, of at least one photoinitiator, and D) 0.05 to 6% by weight, based on the total weight of the coating composition, of an alkoxysilane, the sum of components to being 100% by weight, wherein component is N--aminoethyl-Y-aminopropyltri- methoxysilane or Y-aminopropyltrimethoxysilane or N-methyl- Y-aminopropyltrimethoxysilane or triamino-modified propyltrimethoxysilane. 2. A coating composition as claimed in claim 1, which contains 0.5 to 2% by weight, based on the total weight of the coating composition, of N-0-aminoethyl-y-aminopropyltri- methoxysilane as component 3. A coaUtng composition as claimed in claim 1, which contains 2 to 4% by weight, based on the total weight of the coating composition, of y-aminopropyltrimethoxysilane as component 4. A coating composition as claimed in claim 1, which i 1 24 contains 3 to 5% by weight of N-methyl-y-aminopropyltri- methoxysilane as component A coating composition as claimed in claim 1, which contains 4 to 6% by weight of triamino-modified propyltrimethoxysilane as component 6. A coating composition as claimed in one of claims 1 to wherein monomer is N-vinylpyrrolidone and/or phenoxyethyl acrylate and/or isobornyl acrylate, 7. A coating composition as claimed in one of claims 1 to 6, which additionally contains at least one synergist and/or Scustomary auxiliaries and additives. S 8. A coating composition as claimed in any preceding claim in which the diethylenically unsaturated polyurethane contains urea groups. 9. A process for coating a glass surface, in which S. I) a radiation-curable coating composition is applied, and II) the coating composition is cured by means of UV or electron radiation, which comprises applyig a coating composition as claimed in one of claims 1 to 8. The process as claimed in claim 9, wherein the glass surface is the surface of an optical glass fiber. 11. An optical glass fiber which is coated with a coating composition as claimed in one of claims 1 to 8. 25 12. The use of an optical glass fiber as claimed in claim 11 as an optical waveguide. 13. The use of a radiation-cura' le coating composition as claimed in one of claims 1 to 8 for coating optical glass fibers. 14. A liquid, radiation-curable coating composition for coating glass surface substantially as hereinbefore described with reference to any one of the foregoing examples, apart from the comparison examples. A process for coating a glass surface substantially as hereinbefore described with reference to any one of the foregoing exarl 1es, apart Lfrom the comparison examples. 16. An optical glass fiber which is coated with a coating composition :ibstantially as hereinbefore described with reference to any one of the foregoing examples, apart from the comparison examples. DATED THIS 19TH DAY OF MARCH 1992 0* BASF LACKS FARBEN AG By its Patent Attorneys: "Co GRIFFITH HACK CO Fellows Institute of Patent Attorneys of Australia PAT 88 181 04 Nov. 1988 (0830z) l Abstract of the disclosure i Liquid, radiation-curable coating composition for coating glass surfaces The present invention relates to a liquid, radiation-curable coating composition which contains A) 56 to 89% by weight of at least one diethylenically unsaturated polyurethane optionally containing urea groups, B) 10 to 30% by weight of at least one ethylenically unsaturated monomer, C) 0.5 to 8% by weight of at least one photoinitiator, and D) 0.05 to 6% by weight of N-p-aminoethyl-y-aminopro- pyltrimethoxysilane, y-aminopropyltrimethoxysil-.., N-methyl-7-aminopropyltrimethoxysilane or triamino- modified propyltrimethoxysilane, the sum of components to in each case being 100% by weight, and all by weight data being based on the coating composition. These coating agents are employed for coating glass surfaces, in particular optical glass fibers, and are distinguished by good adhesion, even on exposure to moisture. I; r"L.^?i 7 ONTERNATIONAL SEARCH REPORT International Application No PCT/EP LY~0 1382 I. CLASSIFICATION OF SUBJECT MATTER (it several Classification symbol& apply, Indicate all)I According to International Patent Classification (IPC) or to both National Classification and IPC Int.Cl C03C 25/02 II. IFIELDS SEARCHED Minimum Documentation Searched7 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included tn the Fields Searched 9 Ill. DOCUMENTS CONSIDERED TO BE RELIRVANTO Category Citation of Document, 11 with indiwition, where appropriate, of the relevant Passages It Relevant to Claim No. *3 Y EP, A, 0111280 (DE SOTO INC.) 20 June 1984 see claims 1-12 Y Patent Abstracts of Japan, vol. 7,Nr. 6 (C-156), 15 March 1983 JP, A, 57209855 (UNITAKA K.K.) 23 December 1982 see abstract 1-12 Y DE, A, b437531 YOSHIHARA) 25 Aprii see claims 1 .6,8-12 Special categories of cttd documents: t0 later document Published after the International filing date A"document defining the rjoneral state of the ant which as not or priority dale and not In conflict with the application but consderd t beof a'Acul rlevncecite to understand the principle or theory underlying the consdere tobe o paticuar elevnceinvention E1" eariptr document bui published on or after the Interntational X oueto atclrr~vne h lie neto filin datecannot be considered novel or cannot be considered to document which may throw doubts on priority claim(s) or involve an Inventive step which Is cited to establish the publication date of another document Of Particular relevance;'the claimed Invention citation or other special reason (as specified) cannot be considered to Involve an Inventive step when the document referring to an oral disclosure, use, eithibition or document Is combined with one or more other such docu- other means mnents, such combination being obvious to a person skilled document published prior to the international filing date but In the art. later than the Priority date claimed document member of the same Patent family IV. CERTIFICATION_____________ Dats of the Actual Comptetion of the International Search Data of Mailing of this International Search Report 9 February 1990 (09.02.90) 14 March 1990 (14.03.90) Internationat Searching Authority Signature of Authorized officer EUROPEAN PATENT OFFICE Form PCTISA21O second sheet) (January ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO. EP 8901382 SA 32236 This annex lists the patent family members relating to the patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 05/03/90 The European Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent document Publication Patent family Publication cited in search report date member(s) date EP-A- 0111280 20-06-84 CA-A- 1198083 17-12-85 DE-A- 3437531 25-04-85 JP-A- 60083907 13-05-85 For more details about this annex see Official Journal of the European Patent Ofice, No. 2/82 M For more details about this annex see Official Journal of the European Patent Office, No. 12/82 L a I INTERNATIONALER RECHERCHENBERICHT Internationales Aktenzeichen PCT EP 8 9 0 138 2 1. KILASSIFIKATION DES ANMELDUNGSGEGENSTANDS (be! mohreren Klessiflkcationsavrmbolan sind all* alzugobon) 6 Nach der internationalen Patentklassifikation ader nach der nationalen Kiassifikatian und der IPC Int.CI 5 C 03 C 25/02 It. RECHERCHIERTE SACHGE131ETE Recherchierter Mindestpruifstoff 7 Klassifikationssystem Klassifikationssymbole Int.I. 5 C 03 C Rechetchiete nic~a X-Am Mindestpriitstotf gehorende Veroffentlichungen, soweit diese tinter die recherchierten Sachgebiete fallen 8 III. EINSCHLAGIGE VEROFFENTLICHUNGEN 9 Art Kennzeichnung der Veroffentlichungll,sowelt erforderlich unter Angabe det maligeblichen Teile 12 Beir. Anspruch Nr, 13 Y EP, A, 0111280 (DE SOTO INC.) 20. Juni 1984, 1-12 siehe Patentanspruiche Y Patent Abstracts of Japan, Band 7, Nr. 61 1-12 (C-156), 15. Mdrz 1983 JP, A, 57209855 (UNITAKA K.K.) 23. Dezemnber 1982, siehe Zusammenfassung Y DE, A, 3437531 (M YOSHIHARA) 25. April 1985 1,6,8-12 siehe Patentanspriche 10 *Besondere Kaxegorien von angegebrnen Veroffentlichungen 1 Veroffentlichung, die den allqemeinen Stand der Technik Spitere Veroffentlichung, die nach dem internationalen An. dletiniert, abet nicht als besonders beciuiorm anzusehen ist meldedlatumn oder dem Priorititsdatum veroffentlicht warden 5lteres Dokument, des jedoch ert am odet nach dem interne- ist und mit der Anmeldlung nlcht kollidliert, sondlern nut zum tbonlenAnmldeatu vetffetllht ardn ~Verstindnis des der Erfindlung zugrundeliegenden Ptinzips tionlenAnmedecatumvorffenlict wodenistodet det ihr zugrundeliegenden Theotie angegeben st: Veroffentlichung, die geuignet ist, sinen Ptiorititsanspruch Vetbffentlichung von besonderer Bedeautung; die beansptuch. zweifelhatt e ainen zu lassen, oder dlutch die dlas Verof. eEfnugkn ih l euoe u rldrshrTtg fentlichungasdatum oiner anderen im Rechetchenbericht go- t Etfnund beannchtt$ werde u ricershrTtg namiten Whr~ffentlichung bWWg warden $iu oder die ea eiwru etbruedbtacttwre anderen besondeten Grund angegben ist IWe ausgefuhrt) Veroffentlichung von besondeter Bedeoutung; die beenipruch. "0"Verffntlchngdi sih sf inem~dliheOffenbarung, te Erfindung kann nlcht als auf etfindetischer Titigiceit be- si0 e Veoentcung, ine Asichalufene odr ndce ru3nhenhend bettachtet warden, wann die Veroffentlichung mit sineBentzun. sne ustelun ode anereMa~nhmoteher oder mehreren andeten Veroffentlichungen dlieset Kate. bezieht gorie in Vetbindung gebtacht wind und diese Verbindlun fut "P1" Verbffentlichung, die vor dem intetnationalen Anmeldeda- sinen Fachmann naheliegend ist turn, abet nech dem beenspruchten PIiorititsdatum verbffent- eofnlcug i iglddrebnPtnfmlei Iicht warden istVVrfetihndeMtle esle aetaii s IV. Datum des Abschlusses der internationalen Recherche Absandedatum des internationalen Recherchenbetichts 9. Februar 1990 0 09 Internationale Recherchenbehorde Uts~rIe aesee Europijiches PatenmamtT.R2 LIIS Formblett PCT/ISA/210 (Blatt 2) ljanuor 1985) 11111 ANHANG ZUM INTERNATIONALEN RECHERCHENBERICHT O}BER DIE INTERNATIONALE PATENTANMELDUNG NR. EP 8901382 SA 32236 In diesemn Anhang sind die Mitglieder der Patentfamilien der im obengenannten internationalen Recherchenbericht angefuhrten Patentdok-umente angegeben. Die Angaben fiber die Familienmitglieder entsprecben demn Stand der Datei des EuropAischen Patentamnts am 05/03/90 Diese Angaben dienen nur zur Unterrichtung und erfolgen ohne GewAhr. Im Recherchenbericht Datum der MitgIaed(er) der Datum der angefiihrtes Patentdokument Verbffendichung TPatentfamilie T ver6ffentlichung EP-A- 0111280 20-06-84 CA-A- 1198083 17-12-85 DE-A- 3437531 25-04-85 JP-A- 60083907 13-05-85 Fiur nabere Einzelheiten zu diesem Anhang :siehe Anusblatt des Eiaropaischen Patentamnts, Nr.12/82