content_image/946128.jpg
# CROSSLINKABLE WATERBORNE DISPERSIONS OF HYDROXY FUNCTIONAL POLYDIENE POLYMERS AND AMINO RESINS 

This is a division of application Ser. No. 08/679,164, filed Jul. 12, 1996, now U.S. Pat. No. 5,721,317 which is a continuation of Ser. No. 08/479,583 filed Jun. 7, 1995, abandoned, which is a continuation of Ser. No. 08/277,375, filed Jul. 18, 1994 abandoned. 

## BACKGROUND OF THE INVENTION 

This invention relates to waterborne dispersions of hydroxy functional polydiene polymers. More specifically, the invention relates to waterborne dispersions of such polymers and amino resins which can be crosslinked to make cured films, coatings, adhesives, sealants, caulks, binders and modifiers for asphalt. 

Hydroxy functional polydiene polymers are well known. It has been shown that formulations containing these polymers, a melamine resin, and an acid catalyst can be cured by baking under normal bake conditions. If such formulations could be dispersed in water, the utility of these polymers would be greatly broadened. This would allow preparation of low viscosity, waterborne formulations hav› ing very low volatile organic compound (VOC) contents. By adding waterborne hydroxy functional polydiene polymer dispersions to other water-based products having compatible surfactant systems, these polymers could be used to modify other types of resins and this could be done without concern about phase separation due to incompatibility of the hydroxy functional polydiene polymers and solvent-based resins. 

It is one object of the present invention to provide a crosslinkable waterborne dispersion of hydroxy functional polydiene polymers and amino resins. Another object of this invention is to provide a method for making such crosslink› able waterborne dispersions. 

## SUMMARY OF THE INVENTION 

The present invention provides a water dispersion of a crosslinkable hydroxy functional polydiene polymer com› position which comprises: 

(a) 10 to 65% by weight(% w) of a hydroxy functional polydiene polymer, 

(b) 0.2 to 25% w of a compatible amino resin, 

(c) 0.1 to 10% w of a nonionic surfactant or an anionic surfactant having a volatile cation, and 

( d) the balance water. 

In a preferred embodiment of the present invention, the compatible amino resin is a butylated amino resin and the surfactant is an anionic surfactant composed of an amine salt of an acid which can be used to catalyze the crosslinking of the polymer and the amino resin such as paratoluene sul› fonic acid or dodecylbenzene sulfonic acid. 

This invention also describes processes for making such crosslinkable waterborne dispersions. One method involves making a hot aqueous solution of the surfactant, adding a mixture of a hydroxy functional polydiene polymer and a 60 compatible amino resin to the hot aqueous solution, and then mixing the components under high shear conditions. The preferred method involves mixing together at a temperature of 25° to 90° C. with vigorous agitation a hydroxy functional polydiene polymer, an amino resin, and the desired 65 surfactant, and then adding water to the mixture slowly over a period of at least 15 minutes. 

The hydroxy functional polydiene polymers of the present invention are monools, dials, and polyols of hydrogenated and unhydrogenated low molecular weight diene homopoly› mers and copolymers with more than one diene and/or a vinyl aromatic hydrocarbon. Such copolymers will usually be random copolymers or tapered block copolymers since it is difficult to make low molecular weight copolymers with a sharp division between blocks because the crossover reaction from one monomer to the other is usually slow compared to the progagation reaction. Suitable polymers include monools, dials, and pol yo ls of low molecular weight polybutadiene and polyisoprene and their copolymers with styrene, either hydrogenated or unhydrogenated. 

Hydrogenated polybutadiene dials are preferred for use herein because they are easily prepared, they have low glass transition temperature, and they have excellent weatherabil› ity. The dials, dihydroxylated polybutadienes, are synthe› sized by anionic polymerization of conjugated diene hydro- carbons with lithium initiators. Monools and polyols can also be synthesized in the same manner. This process is well known as described in U.S. Pat. Nos. 4,039,593 and Re. 27,145 which descriptions are incorporated herein by refer› ence. Polymerization commences with a monolithium, dilithium, or polylithium initiator which builds a living polymer backbone at each lithium site. Typical monolithium living polymer structures containing conjugated diene hydrocarbons are: 

<img src='content_image/946128.jpg'>

wherein B represents polymerized units of one or more conjugated diene hydrocarbons such as butadiene or isoprene, A represents polymerized units of one or more vinyl aromatic compounds such as styrene, and X is the residue of a monolithium initiator such as sec-butyllithium. B can also be a copolymer of a conjugated diene and a vinyl aromatic compound. B$_{1 }$ and B$_{2 }$ are formed of different dienes. 

The anionic polymerization of the conjugated diene hydrocarbons is typically carried out in a hydrocarbon solvent containing a structure modifier such as diethylether or glyme (1,2-diethoxyethane) to obtain the desired amount of 1,4-addition. As described in Re. 27,145 which is incor› porated by reference herein, the level of 1,2-addition of a butadiene polymer or copolymer can greatly affect elasto- meric properties after hydrogenation. The 1,2-addition of 1,3-butadiene polymers having terminal functional groups significantly and surprisingly influences the viscosity of the polymers. A 1,2-addition of about 40% is achieved during polymerization at 50° C. with about 6% by volume of diethylether or about 1000 ppm of glyme in the polymer› ization solvent. 

The present invention also contemplates linear unsatur› ated or hydrogenated isoprene polymers having one to two terminal hydroxy groups per molecule and also such poly› mers having additional hydroxy groups. Preferably, the isoprene polymers have greater than 80% 1,4-addition of the isoprene and hydrogenation of at least 90% of the polymer› ized isoprene. The polymers are preferably prepared by anionic polymerization in the absence of microstructure modifiers that increase 3,4-addition of the isoprene. 

The hydroxy functional polydiene polymers may have molecular weights of from about 1,000 to about 3,000,000. 

## DETAILED DESCRIPTION OF THE INVENTION 

