WO1992008747A1

WO1992008747A1 - Novel antioxidant and light stabilizer bound oligomer systems for radiation cured materials

Info

Publication number: WO1992008747A1
Application number: PCT/NL1991/000219
Authority: WO
Inventors: Kevin P. Murray; Chander P. Chawla; Erwin S. Poklacki
Original assignee: Dsm N.V.
Priority date: 1990-11-07
Filing date: 1991-11-07
Publication date: 1992-05-29
Also published as: AU8925591A

Abstract

The performance of ultraviolet light cured coatings may be enhanced through the addition of covalently bound light stabilizer and antioxidant so that the cured films are not subject to degradation or yellowing.

Description

"NOVEL ANTIOXIDANT AND LIGHT

STABILIZER BOUND OLIGOMER

SYSTEMS FOR RADIATION CURED MATERIALS" Background of the Invention

The need to stabilize radiation cured coatings (actinic light or ionizing radiation) to the effects of long term exposure to light and oxygen is well known. The need, for example, for non-yellowing light cured varnishes on medicinal or cosmetic labels is imperative. Any tendency toward yellowing is interpreted by the consumer that the contents are in some way old and not as efficacious. This creates a serious problem with store displays. Similarly, ultraviolet coatings on floor tile must not yellow on exposure to sunlight over long periods of time. Such failure is normally seen as a yellowing of the tile near windows or doors with a gradation to colorless as the distance from the window increases. U.S. Patent No. 4,344,830 discloses the incorporation of hydroxy benzotriazoles in ultraviolet light curable coatings to impart weathering resistance to plastic substrates. These materials were simply admixed with the coating composition and did not react to become part of the polymer.

U.S. Patent No. 4,355,071 discloses the preparation of clear ultraviolet light curable coatings over a pigmented coating which contains about 1 + 20%, based on the weight of the binder, of ultraviolet light stabilizers. The stabilizer is not incorporated in the ultraviolet light curable clear top coat and does not interfere with the cure speed. However, upon curing the stabilizer is free to migrate into the clear top coat to provide protection from discoloration. The idea of incorporating the light stabilizer into the polymer is disclosed in U.S. Patent No. 4,504,628. A stabilizer with a functional group is reacted with a compound having both isocyanate and polymerizable vinyl groups to produce a new monomer. Upon polymerization of compositions containing this new monomer, the stabilizer becomes an integral part of the polymer and is no longer fugitive or extractable. An example of this type of structure might be the reaction product of a hydroxy functional hindered amine stabilizer with isocyanatoethyl methacrylate. Other examples of this type of product are the reaction product of isophorone diisocyanate or toluene diisocyanate with one mole of the stabilizer and one mole of hydroxyethyl acrylate. These monomers may have a high order of volatility, toxicity, and possibly a less desirable rate of polymerization. In addition, complying with all of the regulations of the

Environmental Protection Agency for the introduction of new monomers into commerce can involve prohibitive associated costs.

t.x -m_i- nf the Invention

The present invention relates to a compound containing at least one polymerizable ethylenically unsaturated functional group and at least one stabilizer moiety covalently bonded within. More particularly, the present invention relates to a polyurethane having at least one ethylenically unsaturated functional group and at least one stabilizer moiety, said urethane having a number average molecular weight of 1,000 to 10,000 daltons and being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to 4,000 daltons, an eguimolar mixture of a hydroxy terminated ethylenically unsaturated monomer and stabilizer compounds having a functional group capable of reacting with the isocyanate moiety. Preferably the stabilizer is N-(2,2,6,6- tetramethyl-4-piperidinyl)-N-hydroxybenzenepropionic hydrazide or 3,5-ditertiary butyl-4- hydroxybenzenepropionic hydrazide, alone or in combination and the hydroxy functional ethylenically unsaturated monomer is taken from the classes of acrylates, methacrylates, acrylamides, methacrylamides, maleates and vinyl ethers.

The present invention is also directed to a coating composition that comprises: (i) about 10 to about 90% weight percent based on total weight of the coating composition, of an unsaturated polyurethane having a number average molecular weight of about 1,000 to about 10,000 daltons, being the reaction product of a prepolymer having a number average molecular weight of about 400 to about 2,000 daltons, a diisocyanate and a hydroxy functional unsaturated monomer, (ii) about 0.01 to about 25 weight percent, based on total weight of the coating composition, of a polyurethane having on at least one end an unsaturated moiety and on another end, the bound antioxidant, having a number average molecular weight of about 1,000 to about 10,000 daltons being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to about 4,000 daltons, on eguimolar mixture of hydroxy functional unsaturated monomer and an antioxidant containing a functional group capable of reacting with an isocyanate, (iii) about 0.01 to about 25 weight percent, based on the total weight of the coating composition of a polyurethane having on at least one end an ethylenically unsaturated group and on another, a bound light stabilizer moiety having a number average molecular weight of about 1,000 to about 10,000 daltons being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to about 4,000 daltons, an eguimolar mixture of hydroxy functional ethylenically unsaturated monomer and a light stabilizing compound having a functional group capable of reacting with an isocyanate group; and (IV) about 5 to about 80 weight percent, based on the total weight of the coating composition, of at least one saturated compound that optionally further comprises a photoinitiator.

It has been found that the compositions of the present invention that contain bound light stabilizers and bound antioxidants produce cured coatings which have superior stability without being subject to a loss of these properties by extraction with water or solvents. The antioxidant and light stabilization benefits were permanent properties of the cured films. The stabilizer containing oligomers, since they have polymerizable functional groups only on one end, are bulky monomeric materials which also function as internal plasticizers; that is, they are capable of inhibiting crystallization of polymer chains.

The acrylated polyurethane and the oligomer bound stabilizers are produced sequentially in situ with the acrylated polyurethane being the first to be produced. Conventional photoinitiators can also be present in the compositions of the present invention to initiate polymerization by ultraviolet light and visible light near the ultraviolet wavelength range. The compositions of the present invention will also polymerize in the absence of photoinitiators by the influence of ionizing radiation such as produced by an electron beam machine. Similarly, these compositions may also be polymerized thermally with appropriate thermal free radical initiators, e.g. azobis isobutyronitrile, benzoyl peroxide, or various hydroperoxides.

Detailed Description of the Preferred Embodiments Although this invention is susceptible to embodiment in many different forms, preferred embodiments of this invention are shown. It should be understood, however, that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to embodiments illustrated.

Oligomeric structures useful in radiation curable coatings, either actinic or ionizing, which provide the benefits of antioxidants and light stabilizers but without their undesirable ^* extractabilities are disclosed. These oligomeric structures comprise a polyurethane which contains (meth)aerylate groups and at least one bound stabilizer group, which is attached through a urethane or urea linkage. In practice, two oligomeric structures, one containing an antioxidant moiety and the other a light stabilizing moiety are prepared and used in admixture. These oligomers are used at a 0.01 to 25 weight percent level with oligomers which are totally (meth)acrylated. Further, these oligomers have a number average molecular weight of about 1,000 to 10,000 daltons.

The term "dalton", in its various grammatical forms, defines a unit of mass that is 1/12th the mass of carbon-12. The term ^M(meth)acrylate", and various grammatical forms thereof, identifies esters that are the reaction product of acrylic or methacrylic acid with a hydroxy group-containing compound.

The (meth)aerylate-terminated polyurethane is the reaction product of a prepolymer, an organic diisocyanate and a hydroxy (meth)acrylate. The stabilizing oligomers are reaction products of a prepolymer, organic diisocyanates, a hydroxy (meth)acrylate, and a stabilizing compound. The prepolymer has a carbon chain that can comprise oxygen and/or nitrogen atoms to which the terminal (meth)acrylate functionality is added by use of the diisocyanate. Selection of the prepolymer can a fect the physical properties of the coatings produced from the oligomer-containing composition.

The prepolymer has on average at least about two prepolymer functional groups that are reactive with the isocyanate group, e.g., a hydroxy, mercapto, amine or similar group which has a reactive protonic group. Presently, the preferred prepolymer functional group is a hydroxy group.

The number average molecular weight of the prepolymer is about 500 to about 4,000, preferably about 800 to about 2,500, daltons. Prepolymers are selected from the group consisting of hydroxy or amine terminated polycarbonates, polyesters, polyethers, unsaturated and hydrogenated polybutadienes, polysiloxanes, Bisphenol A- Alkoxylates, fluorinated derivatives of these and mixtures thereof. The reaction of the polyols with the diisocyanate may be conducted so as to simply end cap the hydroxyl groups with isocyanate groups, or to also produce chain extended structures which are isocyanate terminated. The polycarbonate diols are conventionally produced by the alcoholysis of diethylene carbonate with a diol. The diol is an alkylene diol having about 2 to about 12 carbon atoms, e.g., 1,4-butane diol, 1,6-hexane diol, 1,12-dodecane diol and the like. Mixtures of these diols can also be utilized. The polycarbonate diol can contain ether linkages in the backbone in addition to carbonate groups. Thus polycarbonate copolymers of alkylene oxide monomers and the previously described alkylene ether diols are suitable. Suitable alkylene oxide monomers include triethylene glycol and tripropylene glycol, tetrahydrofuran and the like. Admixtures of the polycarbonate diols and polycarbonate copolymer diols can also be utilized.

Suitable polycarbonate diols include Duracarb 122, commercially available from PPG Industries and Permanol KM10-1733, commercially available from Permuthane, Inc. , Ma. Durocarb 122 is produced by the alcoholysis of diethylcarbonate with hexane diol.

Illustrative polyesters include the reaction products of saturated polycarboxylie acids, or their anhydrides, and diols. Suitable saturated polycarboxylic acids and anhydrides include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrachlorophthalic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, malonic acid, pimelic acid, suberic acid, 2,2-dimethylsuccinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylsuccinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylglutaric acid, the like, anhydrides thereof and mixtures thereof. Suitable diols include 1,4-butanediol, 1,8-octane diol, diethylene glycol, 1,6-hexane diol, dimethylol cyclohexane, and the like. Included in this classification are the polycaprolactones, commercially available from Union Carbide under the trade designation Tone Polylol series of products, e.g., Tone 0200, 0221, 0301, 0310, 2201, and 2221. Tone Polyol 0301 and 0310 are trifunctional.

Representatives of the polyether diols are those formed from the polymerization of alkylene oxides such as poly (propylene oxide) , commercially available from Union Carbide under the trade designation Niax PPG 1025 and poly (tetramethylene glycol) , commercially available from DuPont under the trade designation Terathane 1000.

The alkyl substituted poly(tetrahydrofurans) have ring structures that open during polymerization to produce hydroxy terminated polyethers which may be used to make the polymer bound stabilizers of this invention. The alkyl group of the alkyl substituted poly(tetrahydrofurans) has about 1 to about 4 carbon atoms. Representative of the alkyl substituted poly(tetrahydrofurans) is poly(3-methyltetrahydrofuran) . Representative of the cyclic ethers with which the alkyl substituted tetrahydrofurans can be copolymerized are ethylene oxide, propylene oxide, tetrahydrofuran and the like.

Representative of the Bisphenol-A alkoxylates are those wherein the alkoxy group contains about 2 to about 4 carbon atoms, e.g., ethoxy. A commercial

Bisphenol-A alkoxylate is the Bisphenol-A diethyoxylate available under the trade designation Dianol 22 from Akzo Research, The Netherlands.

Representative of siloxanes is poly(dimethylsiloxane) commercially available from Dow Corning under the trade designation DC 193.

Representative of the hydrogenated polybutadiene prepolymers are materials made from butadiene monomers that have a high percentage of 1,2 vinyl structure, are terminated with hydroxyl groups, and are hydrogenated until essentially no unsaturation remains. Such a material is commercially available from Nippon Soda Ltd. through Nissho Iwai, New York, NY as Nisso PB. GI-1000. The fluorinated prepolymers are represented by polyethers based on perfluorinated poly(ethylene oxide) in which the fluorine atoms are in the main chain. Examples of such fluorinated prepolymers include Fomblin Z-DOL-TX from Ausimont, Morristown, N.J. and MDP 5992 from DuPont, Wilmington, Del., a polyether with perfluoroalkyl groups pendant to the main chain.

Any of a wide variety of organic polyisocyanates, alone or in admixture, can be utilized. Representative diisocyanates include isophorone diisocyanate (IPDI) , toluene diisocyanate (TDI) , diphenylmethylene diisocyanate (MDI) , hexamethylene diisocyanate (HMDI) , cyclohexylene diisocyanate, methylene dicyclohexane diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, m-phenylene diisocyanate, 4- chloro-1,3-phenylene diisocyanate, 4,4*-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4- tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4- cyclohexylene diisocyanate, and polyalkyloxide and polyester glycol diisocyanates such as polytetramethylene ether glycol terminated with TDI and polyethylene adipate terminated with TDI, respectively. The hydroxy(meth)acrylate can be a mono(meth)acrylate or a poly(meth)acrylate. Monohydric monoacrylates are presently preferred. The reaction of the isocyanate group with a hydroxy group of the hydroxy (meth)acrylate produces a urethane linkage which results in the formation of a (meth)acrylate terminated urethane.

Suitable monohydric acrylates are the C_j-^ alkyl acrylates and polyacrylates. Illustrative of these acrylates are 2-hydroxyethyl acrylate, 2- hydroxypropyl acrylate, glyceryl diacrylate, and the like. Mixtures of these acrylates are also suitable. The methacrylate counterparts of the above acrylates can also be utilized.

The reactive stabilizers which are preferred are: Luchem HA-R100, N-(2,2,6,6-tetramethyl-4- piperidinyl)-N-aminooxamide and Luchem AOR-300, 3,5-di- tertiary butyl-4-hydroxybenzenepropionic hydrazide. These materials are available from ATOCHEM North America Inc. The N-amino group of both of these compounds is very reactive towards isocyanates and therefore is used to bind the stabilizers to the oligomer covalently. Other reactive UV light stabilizers and antioxidants which have hydroxyl, mercapto, or amino groups may also be used to produce a polymer-bound stabilizer system.

In practice, the oligomers are produced first by the reaction of a diisocyanate with the hydroxy alkyl meth(acrylate) . To facilitate the mixing of the viscous mixture, a monoacrylate ester of low viscosity is used as a solvent for the reaction, e.g. vinyl pyrolidone or octadecyl acrylate. To facilitate the reaction of the isocyanate to produce urethanes, a catalyst is included, e.g., about 0.01 to about 0.3, preferably about 0.04 percent of dibutyltin dilaurate is used. The above reaction product is next reacted with the hydroxy terminated prepolymer. The stoichiometry is so adjusted that there are unreacted isocyanate groups remaining on some of the oligomer molecules. The stabilizing oligomers are then produced, in situ, by reacting the remaining free isocyanate groups with a stoichiometric amount of the stabilizers. Formulation of the coating is usually accomplished in the same vessel as was used for the reaction of the preceding paragraph. Diluent monomers, photoinitiators, stabilizers, adhesion promoters, and the like are added to the oligomer mixture. Preferred photoinitiators are (1) hydroxy- or alkoxy-functional acetophenone derivatives, more preferably hydroxyalkyl phenones, and (2) benzoyl diary1 phosphine oxides. One commercially available compound is the Ciba-Geigy product CGI-369 which is 2- benzyl-dimethylamino-l-4-morphiline phenyl)-butanone-1. Irgacure 184, also from Ciba-Giegy, is another useful acetophenone derivative and has the structure: a- hydroxycyclohexyl phenyl ketone. Still another commercially useful acetophenone derivative is diethoxy acetophenone which is available from Upjohn Chemicals. An example of the phosphine oxide type photoinitiator is 2,4,6-trimethyl benzoyl diphenyl phosphine oxide which is commercially available from BASF under the trade designation Lucirin TPO. This list of photoinitiators is incomplete However, additional commercially available materials are well known to those skilled in the art.

The present invention will be illustrated by the following representative examples.

EXAMPLE 1. An additive bound oligomer of the present invention was prepared in a 2000 milliliter (ml) , 4 neck flask that was equipped with a variable speed paddle stirrer, dry air inlet, thermometer and condenser. Provision was made to heat or cool the flask. A dry air sparge of the flask was initiated. The flask was charged with 186.9 gms. (0.8374 moles) of isophorone diisocyanate (IPDI¹) , 150 gms. of octyl/decyl acrylate (ODA²) as a diluent, 0.30 gms. of phenothiazine³ (radical inhibitor) and 0.70 gms. of dibutyltindilaurate (DBTDL⁴) (urethane catalyst) .

Next charged to the flask over a period of 1/2 hour while the temperature was maintained below 40*C, was 45.8 gms. (0.3944 moles) of hydroxy ethyl acrylate (HEA)⁵. The contents were stirred at 40*c for one hour to allow sufficient time for all of the HEA to react with the IPDI. The progress of the reaction was determined by a standard procedure of treating an aliquot of the reaction mixture with an excess of dibutylamine and then backtitrating the excess dibutylamine with dilute standard HC1 solution.

The flask was next charged with 531 gms. (0.5783 moles) of an aliphatic polycarbonate diol (Permanol KM-10-1733⁶) blended with 8.71 g (0.0298 moles) of 3,5-ditertiary buty1-4-hydroxy benzene propionic hydrazide (Luchem AOR 300)⁷ over a period of ifteen minutes and the temperature was increased to 70*C. To the reaction mixture was added an additional 43.0 gms. of ODA for a total of 20% diluent. The reaction contents were stirred at 70*C for eight hours to ensure the complete reaction of the polycarbonate diol. The % unreacted isocyanate groups were determined to ensure that all of the IPDI and the IPDI-HEA had been incorporated into the oligomer.

Next charged into the reactor was 8.71 gms. (0.0298 moles) of finely powdered 3,5-ditertiary butyl- 4-hydroxybenzene propionic hydrazide (Luchem AOR 300) and 8.48 gms (0.0350 moles) of finely powdered N- (2,2,6,6-tetramethyl-4-piperdinyl)-N-amino oxamide (Luchem HA-R100)⁸. The addition of these last two reagents took 20 minutes. The reaction mixture was stirred at 70"C for two and a half hours and then the temperature was increased to 90*C. The contents were stirred at 90*C for one hour and forty minutes. An aliquot indicated essentially no isocyanate functionality left and the heating was stopped.

The additive bound oligomer was admixed with the diluent monomers Aronix M-113⁹ and V-Pyrole¹⁰, adhesion promoter (MEMO)¹¹ and the photoinitiator CGI- 369¹² in a weight ratio of oligomer:Aronix M-113:V- Pyrole:MEMO:CGI-369 of about 59.8: 34: 4.1: 1: 1 to produce a liquid composition of the invention. The liquid composition was drawn down as a film on a glass plate and cured using a "D" Lamp from Fusion Curing Systems, Rockville, MD. The "D" Lamp emits actinic energy having a wave length of about 200 to about 470nm, with the peak actinic energy being about 380 nm and a power output of about 300 watts per linear inch. The cured film showed non-extractability of the additives.

1.) IPDI, isophorone diisocyanate, commercially available from Huls America, Nuodex Inc. Piscataway,

N.J..

2.) ODA, octyl/decyl acrylate, commercially available from Radcure Specialties, Louisville, KY.

3.) Phenothiazine, commercially available from ICI, Wilmington Delaware.

4.) DBTDL, dibutyltin dilaurate, commercially available from Mooney Chemical Co.

5.) HEA, hydroxyethyl acrylate, commercially available form Dow Chemical Co., Midland Michigan. 6.) Permanol M-1—1733, commercially available from

Permuthane Coatings, Peabody, MA.

7.) Luchem AOR 300, commercially available from the

Lucidol division of the Pennwalt Corporation, Buffalo

N.Y. 8.) Luchem HA-R100, commercially available from the

Lucidol division of the Pennwalt Corporation, Buffalo

N. Y.

9.) Aronix M-113, ethoxylated nonylphenol acrylate, commercially available from Tao Gosei Chemical Industry Co. Ltd. Japan 10.) V-Pyrole, commercially available from GAF Corporation, New York, N.Y..

11.) MEMO, gamma-methacryloxypropyltrimethoxysilane, commercially available from Huls, Bristol Pa. 12.) CGI-369, 2-benzyl-2-dimethylamino-l-(4-morpholino phenyl)-butanone-1, commercially available from Ciba Geigy, Ardsley, NY.

EXAMPLE 2. In a second formulated composition, the bound oligomer of Example 1. was admixed with the diluent monomer Aronix M-113, adhesion promoter (MEMO) and the photoinitiator Lucirin TPO in a weight ratio of oligomer:Aronix M-113:MEMO:Lucirin TPO¹³ about 53.2:43.6:1.1:2.1. The liquid composition was drawn down on a glass plate as a film and cured using the "D" lamp. The cured film was immersed in acetone for 24 hours and dried. The dried film was placed in a Dupont 912 Differential Scanning Calorimeter and heated at a rate of lθ^'c/ minute. The temperature at which exothermic decomposition occurs (oxidation induction temperature or OIT) was recorded. The value obtained was about the same (257^*C for control and 264^*C after 24 hours immersion in acetone) , the unextracted cured film demonstrating the non-extractability of the stabilizer system. Thermogravimetric analysis (TGA)¹⁴ showed very little weight loss (-1.1%) on heating at 200^*C for forty minutes. An analysis of the oligomer showed that both the additives were bound to the oligomer backbone.

13.) Lucirin TPO, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, commercially available from BASF Corporation Germany. 14.) TGA conducted on a DuPont 951 Thermogravimetric Analysis Instrument. EXAMPLE 3. The following composition was prepared as a control. A similar oligomer based on HEA/IPDI/PERMANOL/IPDI/HEA was prepared without any bound additives. The composition contained 57% oligomer, 33% Aronix M-113, 4% V-Pyrole, 4% Irgacure 184¹⁵, 1% MEMO, 0.5% Tinuvin 770¹⁶, and 0.5% Irganox 1035¹⁷.

The sample was cured as in Example 1 and extracted with acetone. Differential scanning calorimetry gave a reduction in OIT of 40 ^*C as compared with the OIT of the unextracted film. The Thermogravimetric Analysis gave a weight loss of 4.4% for the acetone extracted film.

15.) Irgacure 184, 1-hydroxycyclohexyl phenyl ketone, commercially available from Ciba Geigy, Ardsley NY. 16.) Tinuvin 770, Bis (2,2,6,6-tetramethyl-4-piperdinyl) sebacate, commercially available from Ciba Geigy. 17.) Irganox 1035, thiodiethylene bis-(3,5-di- tertiarybutyl-4-hydroxy) hydrocinnamate, commercially available from Ciba Geigy.

EXAMPLE 4. An antioxidant bound oligomer of the present invention was prepared utilizing a flask as described in Example 1 that was charged with 186.89 gms (0.8375 moles) of isophoronediisocyanate (IPDI), 150.15 gms of octyl/decyl acrylate (ODA) , 0.30 gms phenothiazine and 0.60 gms of dibutyltindilaurate (DBTDL). The dry air sparge was started from the beginning of the addition to the flask. To the mixture in the flask was added over a period of one half hour 49.44 gms. (0.4258) moles of hydroxyethyl acrylate (HEA) , during which time the temperature was maintained below 40*C. The contents were stirred at 40*C for one hour to allow sufficient time for the HEA to react completely with the IPDI. At this time, the free isocyanate % was determined as described in Example 1. The temperature was increased to 70'C while

541.97 gms (1.181 moles) of Per anol KM10-1733 blended with 8.7 gms (0.0298 moles) of Luchem AOR 300⁷ was added over a period of fifteen minutes. An additional 47.15 gms of ODA was added to the reaction mixture. The contents of the reaction mixture were stirred for ten hours at 7θ"c. An aliquot sample showed essentially all of the IPDI had reacted.

The antioxidant bound oligomer was admixed with the diluent monomers Aronix M-113 and V-Pyrole, adhesion promoter (MEMO), Tinuvin 770, and the photoinitiator CGI-369 in a ratio of about 59.3:34:4:1.0:0.5:1.0 to produce a liquid composition of the invention. A film of the composition was cured using the ^MDⁿ Lamp. The cured film showed non- extractability of the additive. An analysis of the oligomer showed that the additive was bound to the oligomer.

EXAMPLE 5. A light stabilizer bound oligomer of the present invention was prepared utilizing a flask described in Example 1 that was charged with 186.89 g (0.8375 moles) of isophorondiisocyanate (IPDI), 150.15 g of octyl/decyl acrylate (ODA), 0.30 g of phenothiazine and 0.60 g of dibutyltindilaurate (DBTDL). The air sparge was started from the beginning of the addition to the flask. 47.02 g (0.4049 moles) of hydroxy ethyl acrylate (HEA) was added to the reaction mixture over a period of a half hour, during which time the temperature was maintained below 40^*C. The contents were stirred at 40^*C for 1 hour to allow sufficient time for HEA to react with IPDI. At this time, the amount of remaining NCO groups was determined by a standard procedure of backtitrating ejcess dibutylamine with dilute HC1 solution.

The temperature of the reaction mixture was increased to 70^*C and 540.06 g (0.5882 moles) of an aliphatic polycarbonate diol (Per anol KM10-1733) was added to it over a period of 15 minutes. The reaction contents were stirred at 70^*C for 8 hours to allow sufficient time for the reaction of polycarbonate diol hydroxy groups to react with the isocyanate groups. At this time, percent NCO was determined. 5.99 g (0.0247 moles) of N-(2,2,6,6-tetramethyl-4-piperdinyl)-N-amino oxamide (Luchem HA-R100) was added to the reaction mixture over a period of 10 minutes. An additional 44.99 g of ODA was added to the reaction mixture. The reaction temperature was increased to 90^*C and the contents were stirred for seven and a half hours. An aliquot sample indicated essentially no isocyanate functionality remaining and heating was stopped. The material was poured out of the reaction vessel into a container.

The light stabilizer bound oligomer was admixed with the diluent monomers Aronix M-113 and V- Pyrol, adhesion promoter (MEMO), Irganox 1035 and the photoinitiator CGI-369 from Ciba-Geigy in a weight ratio of oligomer: Aronix M-113: V-Pyrol: MEMO: Irganox 1035: CGI-369 about 59.2:34.1:4.1:1.0:0.5:1.0 to produce a liquid composition of the invention. A film of this composition was cured using the ⁿDⁿ lamp. The cured film showed non-extractability of the light stabilizer. An analysis of the oligomer showed that the additive was bound to the oligomer backbone. EXAMPLE 6. Another additive bound oligomer of the present invention was prepared utilizing a flask as described in Example 1 that was charged with 187.79 g (0.8375 moles) of isophorondiisocyanate (IPDI), 150.05 g of octyl/decyl acrylate (ODA), 0.30 g of phenothiazine and 0.61 g of dibutyltindilaurate (DBTDL) . The air sparge was started from the beginning of the addition to the flask. 45.30 g (0.3901 moles) of hydroxy ethyl acrylate (HEA) was added to the reaction mixture over a period of a 1/2 hour during which time the temperature was maintained below 4θ^"c. The reaction contents were stirred at 40^*C for 1 hour to allow sufficient time for HEA to reach with IPDI. At this time, the amount of remaining NCO groups was determined by a standard procedure of backtitrating excess dibutylamine with dilute HC1 solution.

The temperature of the reaction mixture was increased to 70^*C and 521.35 g (0.5678 moles) of an aliphatic polycarbonate diol (Permanol kmlO-1733) was added to it over a period of 10-15 minutes. The reaction contents were stirred at 70^*C for 8 hours to allow sufficient time for the reaction of polycarbonate diol hydroxy groups to react with the isocyanate groups. 8.71 g (0.0298 moles) of 3,5-ditertiary butyl-4- hydroxybenzene propionic hydrazide (Luchem AOR 300) was added to the reaction mixture followed by the addition of 39.80 g of ODA. The reaction contents were stirred for one and a half hours at 70^*C. At this time a sample for percent NCO was taken. 8.71 g (0.0359 moles) of N- (2,2,6,6-tetramethyl-4-piperdinyl)-N-aminooxamide (Luchem HA-R100) was added over a period of 10 minutes followed by the addition of 59.50 g ODA. The reaction mixture was stirred for 2 hours at 70^*C and then the temperature was increased to 80^*C. After 1/2 hour of stirring at 80^*C the temperature was decreased to 70^*C. An aliquot sample indicated no isocyanate functionality remaining. The heating was stopped and the material was poured out of the reaction vessel into a container. The additive bound oligomer was admixed with the diluent monomer Aronix M-113, adhesion promoter (MEMO) , and the photoinitiator Lucirin TPO in a weight ratio of oligomer: Aronix M-113: MEMO: Lucirin TPO about 50.48:46.67:0.94:1.90 to produce a liquid composition of the invention. A film of this composition was cured using the "D" lamp. Differential Scanning Calorimetry of the cured film extracted with acetone showed essentially no change in OIT compared to the unextracted film. Thermogravimetric Analysis of the acetone extracted film showed very little weight loss (1.14%) on heating at 200^*C for 40 minutes.

Claims

WE CLAIM:

1. A compound containing at least one polymerizable ethylenically unsaturated functional group and at least one stabilizer moiety covalently bonded within.

2. A polyurethane having at least one ethylenically unsaturated functional group and at least one stabilizer moiety, said urethane having a number average molecular weight of 1,000 to 10,000 daltons and being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to 4,000 daltons, an eguimolar mixture of a hydroxy terminated ethylenically unsaturated monomer and stabilizer compounds having a functional group capable of reacting with the isocyanate moiety.

3. The polyurethane of claim 2 wherein the stabilizer is N-(2,2,6,6-tetramethyl-4-piperidinyl)-N- hydroxybenzenepropionic hydrazide.

4. The polyurethane of claim 2 wherein the stabilizer is 3,5 ditertiary butyl-4- hydroxybenzenepropionic hydrazide.

5. The polyurethane of claim 2 wherein the stabilizers are both N-(2,2,6,6-tetramethy1-4- piperdinyl)-N-hydroxybenzene propionic hydrazide and 3,5 ditertiary butyl-4-hydroxy benzene propionic hydrazide.

6. The polyurethane of claim 2 wherein the hydroxy functional ethylenically unsaturated monomer is taken from the classes of acrylates, methacrylates, acrylamides, methacrylamides, maleates and vinyl ethers.

7. A coating composition that comprises: (i) about 10 to about 90% weight percent based on total weight of the coating composition, of an unsaturated polyurethane having a number average molecular weight of about 1,000 to about 10,000 daltons, being the reaction product of a prepolymer having a number average molecular weight of about 400 to about 2,000 daltons, a diisocyanate and a hydroxy functional unsaturated monomer, (ii) about 0.01 to about 25 weight percent, based on total weight of the coating composition, of a polyurethane having on at least one end an unsaturated moiety and on another end, the bound antioxidant, having a number average molecular weight of about 1,000 to about 10,000 daltons being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to about 4,000 daltons, an eguimolar mixture of hydroxy functional unsaturated monomer and an antioxidant containing a functional group capable of reacting with an isocyanate, (iii) about 0.01 to about 25 weight percent, based on the total weight of the coating composition of a polyurethane having on at least one end an ethylenically unsaturated group and on another, a bound light stabilizer moiety having a number average molecular weight of about 1,000 to about 10,000 daltons being the reaction product of an isocyanate terminated prepolymer having a number average molecular weight of about 500 to about 4,000 daltons, an eguimolar mixture of hydroxy functional ethylenically unsaturated monomer and a light stabilizing compound having a functional group capable of reacting with an isocyanate group; and (iv) about 5 to about 80 weight percent, based on the total weight of the coating composition, of at least one unsaturated compound.

8. The coating composition of claim 7 wherein the stabilizer is N-(2,2,6,6,-tetramethyl-4- piperidinyl)-N-hydroxybenzenepropionic hydrazide.

9. The coating composition of claim 7 wherein the stabilizer is 3,5 ditertiary but l-4-hydroxybenzene propionic hydrazide.

10. The coating composition of claim 7 wherein the stabilizers are N-(2,2,6,6-tetramethyl-4- piperdinyl)-N-hydroxybenzene propionic hydrazide and 3,5 ditertiary butyl-4-hydroxy benzene propionic hydrazide.

11. The coating composition of claim 7 wherein the hydroxy functional ethylenically unsaturated monomers are taken from the classes of acrylates, methacrylates, acrylamides, methacrylamides, maleates and vinyl ethers.

12. The coating composition of claim 6 that further comprises a photoinitiator.