Polybutadiene (meth) acrylates are well known articles of commerce. Examples include CN301, CN302 and CN303 from Sartomer Company. These products are used in radiation or peroxide cured inks, coatings, adhesives, printing plates and other applications. Beneficial properties imparted by these materials include high flexibility, low Tg, hydrophobicity, chemical resistance and adhesion to substrates. One drawback of these products is that they have limited oxidative stability with respect to weathering and heat ageing which has limited their use. In addition, the hydroxyl-terminated poly (ethylene-butylene) resins are not widely available and their (meth) acrylate derivatives and properties have not been studied.

We have discovered that hydrogenated hydroxyl-terminated polybutadiene resins in which the terminal hydroxyl functionality is derived from an alkylene oxide have good in process stability and make products that are resistant to premature crosslinking or gellation.

We have successfully hydrogenated the above mentioned hydroxy terminated polybutadienes and the resulted materials are poly (ethylene-butylene) copolymers with hydroxyl-terminal groups at the two ends. These new materials can be converted into (meth) acrylates, which are novel. Urethane (meth) acrylates based on hydroxyl-terminated polybutadiene with alkylene oxide derived terminal hydroxyl groups have been described (U. S. Pat. 4,587, 201; U. S. Pat.

4,031, 066; Japanese Unexamined Patent 2002-371101 and references cited therein).

A first subject of the invention relates to a (meth) acrylated polymer bearing terminal (meth) acrylic ester groups and resulting from alkoxylated derivatives of hydrogenated hydroxyl-terminated polybutadienes (resins), with a degree of alkoxylation n (average number of alkoxy units per hydroxyl group) ranging from 1 to 100 and preferably from 1 to 30 and a number of terminal (meth) acrylic ester groups per molecule, ranging from about 1 to 15 more particularly from about 1 to 6, preferably from about 1 to 3 and more preferably from 1.5 to 2.5.

The said hydrogenated polybutadienes have the structure of poly (ethylene-butylene) copolymers. The invention does also relate to a composition comprising at least one of the said (meth) acrylated polymers.

More particularly, the polymer according to the invention may have the following formula, according to Structure 1:

Structure 1 wherein R is H, Me, Et or C6H5, R'is H or Me, n is a number from 1 to 100, Z is a number from 1 to 3, f is a number from 1 to 5, preferably from 1 to 3, with f = 1, if B is nothing A is the residue of a hydrogenated polybutadiene backbone, and B is nothing (just a simple bond) or B is a difunctional organic linking group, residue of a difunctional organic group linked by the following two linking end-groups: ester-ester, or urethane-ester.

The global functionality or the global number of (meth) acrylic terminal groups per molecule may be represented by the product of numbers f by Z (f. Z). Number f represents the number of (meth) acrylic groups per hydroxyl reactive group and the number Z represents the number of hydroxyl reactive groups per molecule (of alkoxylated hydrogenated polybutadiene). The global functionality f. Z ranges from 1 to 15, more particularly from 1 to 6, preferably from 1 to 3 and more preferably from 1.5 to 2.5.

The materials of the current invention will find use in coatings, inks or adhesives cured by UV or EB radiation, peroxides or Michael addition. Specific end uses include, but are not limited to: photopolymer printing plates, sealants, caulks, encapsulents, road marking paints, photoresists, binders, impact modifiers, polymer modifiers, oxygen or water vapor barrier coatings, conformal coatings, solder masks, pigment dispersions, stereo lithography, laminating resins, grafted co-polymers, composites, optical fiber coatings, paper coatings,

metal coatings, glass coatings, plastic coatings, wood coatings, waterproofing materials, electrical insulating materials, automotive belts or hoses, tires, engine mounts, gaskets, golf ball cores and rubber rolls.

The polymer (backbone) may be prepared by reaction of a hydrogenated hydroxyl- terminated polybutadiene and of an alkylene oxide.

The alkylene oxide used to generate the terminal hydroxyl groups can be selected from any of those known in the prior art. Preferred examples include ethylene oxide, propylene oxide, butylene oxides, and styrene oxide. Most preferred are ethylene oxide, propylene oxide, and mixtures thereof. The number of alkylene oxide units can range from 1 to about 100 per reactive hydroxyl group. A preferred range is from 1 to about 30.

The poly (ethylene-butylene) copolymer resin can be of any molecular weight and its microstructure is not critical to the invention, it is derived from the hydrogenation of hydroxyl-terminated polybutadiene. Molecular weights in the range of 500 to 10,000 Daltons are preferred. For polybutadiene resins, microstructure refers to the amounts 1,2-vs. 1,4- addition and the ratio of cis to trans double bonds in the 1, 4-addition portion. The amount of 1,2-addition is often referred to as vinyl content. The vinyl content of the polybutadiene can range from about 5% to about 90%. The ratio of cis to trans double bonds can range from about 1: 10 to about 10: 1. The average number of reactive terminal hydroxyl groups per molecule which is represented by Z can range from about 1 to 3. A preferred range of Z is from about 1.5 to 2.5.

The alkylene oxide can be incorporated into the polybutadiene resin by either an"in situ"procedure or in a secondary reaction step between an isolated polybutadiene resin and an alkylene oxide. The in-situ procedure would be used in the case where the polybutadiene resin is made by anionic polymerization and the alkylene oxide is added to the active polymerization mixture. In the case where the alkylene oxide is added in a secondary reaction step, the polybutadiene resin could be made by anionic or free radical polymerization. The alkylene oxide could be incorporated by any of the methods known in the art for effecting alkoxylation of alcohols, diols or polyhydroxylic materials.

The (meth) acrylate ester can be introduced or formed by transesterification, direct esterification, reaction with (meth) acrylic halides or anhydrides; by urethane reaction for example by reacting the hydroxyl terminated alkoxylated hydrogenated polybutadiene with a diisocyanate and a hydroxy functional (meth) acrylate; and by reacting with cyclic acid

anhydride followed with epoxide-or hydroxyl-containing (meth) acrylates or diepoxides and (meth) acrylic acid. Transesterification, direct esterification, and urethane reaction are the preferred industrial methods.

For example, the polymer according to the invention may be prepared by a transesterification reaction between the alkoxylated hydrogenated hydroxyl-terminated polybutadiene resin and a low molecular weight (meth) acrylate ester, such as: methyl (meth) acrylate, ethyl (meth) acrylate, n-or iso-propyl (meth) acrylate, or n-, iso-, or tert-butyl (meth) acrylate.

The said transesterification reaction is preferably catalyzed by a metal alkoxide, metal oxide, Lewis acid, or other catalysts or combinations known in the art to catalyze transesterifications.

Another possibility is the direct esterification of alkoxylated hydrogenated hydroxyl- terminated polybutadiene resin with acrylic and/or (meth) acrylic acid, in which case the reaction may be catalyzed by sulfuric acid, para-toluenesulfonic acid, methanesulfonic acid, or other strong mineral or organic acids known to catalyze esterification reactions.

In both cases of transesterification or of direct esterification processes, f is 1 and the number of (meth) acrylic ester groups per molecule f. Z corresponds to the number Z of reactive hydroxyl groups, which ranges from about 1 to 3 and preferably from 1.5 to 2.5.

When the urethane reaction is used for introducing the (meth) acrylate terminal groups the said reaction occurs between the alkoxylated hydrogenated hydroxyl-terminated polybutadiene resin with a diisocyanate and a hydroxyl functional (meth) acrylate.

The said diisocyanate may be selected from: isophorone diisocyanate, toluene diisocyanate, diphenylmethylene diisocyanate, hydrogenated diphenylmethylene diisocyanate, hexamethylene diisocyanate and their derivatives, while the said hydroxyl functional (meth) acrylate may be selected from : hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, pentaerythritol triacrylate, trimethylolpropane diacrylate.

Another object of the invention relates to a process of preparation of the polymer as defined according to the invention.

A first process of preparation may comprise the following steps : a) alkoxylation reaction of a hydrogenated hydroxyl-functional polybutadiene resin with an alkylene oxide

b) transesterification reaction of the resulting alkoxylated resin of step a), with a low molecular weight (meth) acrylate. The transesterification conditions may be selected as defined above.

In a second alternative process, the first step b) remains unchanged, with the second one b), replaced by a direct esterification reaction of the resulting alkoxylated resin of step a), with acrylic or methacrylic acid. In a third process option, the second step b) is replaced by a urethane reaction of the resulting alkoxylated resin of step a), with a diisocyanate and an hydroxyl functional (meth) acrylate, which may be selected according to conditions as defined above.

Another object of the present invention relates to a composition prepared by curing the composition according to the invention, comprising at least one polymer as defined according to the present invention. The said curable compositions may be heat-curable (including P- curable) or radiation curable (UV-curable or EB-curable or high energy radiation-curable).

A final object of the invention relates to an article comprising a cured composition as defined according to the present invention.

Such articles or cured compositions may be in the form of, or used as: a photopolymer printing plate, sealant, caulk, encapsulent, road marking paint, photoresist, binder, impact modifier, polymer modifier, oxygen or water vapor barrier coating, conformal coating, solder mask, pigment dispersion, stereo lithograph, laminating resin, grafted co-polymer, composite, optical fiber coating, paper coating, metal coating, glass coating, plastic coating, wood coating, waterproofing material, electrical insulating material, automotive belt or hose, tire, engine mount, gasket, golf ball core, and rubber roll. Consequently, such specific uses of the said polymer or of the compositions comprising such a polymer are also part of the present invention.

EXAMPLES Example 1.

A 1 liter multi-neck round bottom flask fitted with a mechanical agitator, thermocouple, and Dean-Stark trap was charged with heptane (240 g), acrylic acid (18 g), methanesulfonic acid (4. 1 g), hydroquinone monomethyl ether (0.6 g) and a ethoxylated hydrogenated hydroxyl-terminated polybutadiene resin with Mn of about 3000 (337 g), with hydroxyl functionality Z of about 2, corresponding to 37 mg KOH/g. The ethoxylation degree

n per hydroxyl group ranges from 1 to 3 with an average n of about 1.2 ethoxy (EO) units per hydroxyl. The mixture was heated to reflux to remove water of reaction and reflux was maintained until water production stopped. After removal of the strong acid catalyst, solvent and excess acrylic acid the final product was obtained as a viscous light brown liquid with the following properties: Brookfield viscosity at 60°C of 1990 mPa. s (1990 cP) and APHA color of 200.

Example 2.

A 3 liter multi-neck round bottom flask fitted with a mechanical agitator, thermocouple was charged with isophorone diisocyanate (244.2 g), dibutyltin dilaurate (2.5 g), hydroxyethyl acrylate (127.6 g), hydroquinone monomethyl ether (6.0 g). To this mixture an ethoxylated hydrogenated hydroxyl-terminated polybutadiene resin with Mn of ca. 3000 (1672 g), with hydroxyl functionality Z of about 2 corresponding to 37 mg KOH/g, was added slowly. The ethoxylation degree n per hydroxyl group ranges from 1 to 3 with an average n of about 1.2 ethoxy (EO) units per hydroxyl. The mixture was heated and mixed at 80°C for 6 hours. The final product was obtained as a viscous clear liquid with the following properties: Brookfield viscosity at 60°C of 70200 mPa. s (70,200 cP) and APHA color of 100.

While the invention has been described and illustrated in details herein, various alternatives, modifications, and improvements should be readily apparent to those skilled in this art without departing from the spirit and scope of the invention. The present invention, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. Although the invention has been depicted and described and is defined by reference to particular preferred embodiments of the invention, such references do not imply a limitation on the invention, and no such limitation is to be inferred. The invention is capable of considerable modification, alteration and equivalents in form and function, as will occur to those of ordinary skill in the pertinent arts. The depicted and described preferred embodiments of the invention are exemplary only and are not exhaustive of the scope of the invention. Consequently, the invention is intended to be limited only by the spirit and scope of the appended claims, giving full cognizance to equivalents in all respects.