COPOLYMERS FROM POLYALKYLENE OXIDES CONTAINING A MALEATE REACTIVE DOUBLE BOND AND VINYL ACETATE

Deceinber 22, 1989 COPOLYMERS FROM POLYALKYLENE OXIDES CONTAINING A MALEATE REACTIVE DOUBLE BOND AND VINYL ACETATE 1. Field of the Invention This invention relates to copolymers based on vinyl acetate and a polyalkylene oxide containing a maleate reactive double bond.

BACKGROUND OF THE INVENTION Vinyl acetate is a relatively inexpensive material from which polymers may be produced. Heretofor, polymerization of vinyl acetate produced molecules of relatively high viscosity, and having low hydroxyl functionality. Such characteristics of polyvinyl acetate make it undesirable as a polyol, and more particularly undesirable for use in the production of urethanes.

Further, vinyl acetate is a monomer with relatively low reactivity and thus the polymerization of such a monomer requires a great deal of heat or excess quantities of initiator.

Thus, polymers of vinyl acetate which have relatively low viscosity, have acceptable functionality, and require relatively low heat or acceptable amounts of initiator to produce would be advantageous as polyols, and more particularly for use in the production of urethanes.

Summary of the Invention The present invention provides vinyl acetate based copolymers prepared from the free radical copolymerization of vinyl acetate and polyalkylene oxiâe(s) having a maleate unit. Preferably, the vinyl acetate based copolymers have the general formula I:

O " 3 C-OR* R1- ( CH2-ÇH ) x ( ÇH-CH ) y -R2 I * (I) O C-OR I H c=o o I CH3 wherein R is a polyalkylene oxide, R1 and R2 are each end groups, preferably hydroxyl or isopropoxyl groups, and x is equal to or greater than y.

The polyalkylene oxide having a maleate unit has the general formula II, O R-0-C-CH=CH-C-0-R4 (II) ll wherein R is a polyalkylene oxide and R3 is an oxide cap.

The vinyl acetate based copolymers of the present invention have relatively low viscosity, have sufficient functionality for use as a polyol and for use in the production of urethanes, and are soluble in polyethers.

Detailed Description of the Invention In one embodiment, the invention provides, a modified polyvinyl acetate from the free radical copolymerization of vinyl acetate and polyalkylene oxiâe(s) having a maleate unit of the general formula II o R-0-Ç-CH=CH-C-0-RJ (II) If O wherein R is a polyalkylene oxide; preferably polyethylene oxide, polypropylene oxide, polybutylene oxide or polytetrahydrofuran, and R3 is an oxide cap, preferably polyethylene oxide or polypropylene oxide and having from about 0 to about 5 oxide units. The molecular weight of the polyalkylene oxide may vary but is preferably in the range of about 200 to about 2000 grams per mole. The copolymer has a number average molecular weight (GPC MWn) ranging from about 500 to about 5000, and more preferably, from about 500 to about 2000. The copolymers have a viscosity ranging from about 5000 to about 100,000 cP, and preferably from about 40,000 to about 100,000 cP § 250C. The polyalkylene oxide may be synthesized with a variety of initiators which are discussed in greater detail hereafter.

The polyalkylene oxide having a maleate unit is polymerized with vinyl acetate to produce a copolymer of the general formula 1 :

O C-OR3 (I) R1- ( CH ? -CH ) „ ( CH-CH—» ) v R2 I I y O C-OR I H c=o o I CH3 wherein R is a polyalkylene oxide as described above, R1 and r2 are em3 groups, preferably each being selected from the group consisting of hydroxyl and/or isopropoxyl, and wherein x is 50 - 99.999 mole percent and y is 0.001 - 50 mole percent; preferably x is 75 - 99.995 mole percent and y is 0.005 - 25 mole percent, and most preferably x is 85 - 99.995 mole percent and y is 0.005 - 15 mole percent, and R3 is an oxide cap, preferably polyethylene oxide or polypropylene oxide having from about 0 to 5 oxide units.

In another embodiment, the vinyl acetate based copolymer, prepared from the free radical copolymerization of vinyl acetate and polyalkylene oxide(s) having a maleate, includes a vinyl alcohol group. The vinyl alcohol group may be present in an amount ranging from trace quantities to about five mole percent. Such copolymers preferably have the formula:

o it 3 c-oir 1 I 2 RMCI-ÇH)- (CH2-ÇH)x - (ÇH-CH)y-ir OH O C-OR I c=o o I CH3 wherein R is a polyalkylene oxide as described above, R1 and R2 are end groups, preferably each being selected from the group consisting of hydroxyl and isopropoxyl, and wherein x is 50-99.999 mole percent and y is 0.001-50 mole percent and x* ranges from trace quantities to about 5 mole percent, preferably x is 75-99.999 mole percent and y is 0.005-25 mole percent, and most preferably x is 85-99.995 mole percent and y is 0.005-15 mole percent, and R3 is an oxide cap, preferably polyethylene oxide or polypropylene oxide having from about 0 to 5 oxide units.

The polyalkylene oxide in the above formulas are generally prepared by well-known methods, for example by the base catalyzed addition of alkylene oxide, preferably ethylene oxide, propylene oxide or butylène oxide to initiator molecule containing on an average two or more active hydrogens. Also acid catalyzed polymerization of tetrahydrofuran is suitable. Preferably such initiators include methanol and solketal. Examples of other suitable initiator molecules include dihydric initiators such as ethylene glycol, propylene glycol, butylène glycol, neopentyl glycol, 1,6-hexanediol, hydroquinone, resorcinol, the bisphenols, aniline and other aromatic monoamines, aliphatic monoamines, and monoesters of glycerine; trihydric initiators such as glycerine, trimethylolpropane, trimethylolethane, N-alkylphenylenediamines, mono-, di, and trialkanolantines; tetrahydric initiators such as ethylene diamine, propylenediamine, 2,4'-, 2,2'-, and 4,4'- methylenedianiline, toluenediamine, and pentaerythritol; pentahydric initiators such as diethylenetriamine; and hexahydric and octahydric initiators such as sorbitol and sucrose.

Addition of alkylene oxide to the initiator molecules may take place simultaneously or sequentially when more than one alkylene oxide is used, resulting in block.

heteric, and block-heteric polyoxyalkylene polyethers. The number of hydroxyl groups will generally equal the number of active hydrogens in the initiator molecule. Processes for preparing such polyethers are described both in the Polyurethane Handbook and Polyurethanes; Chemistry and Technology as well as in many patents, for example U.S.

Patents 1,922, 451; 2,674,619; 1,922,459; 3,190,927; and 3,346,557.

By way of example, suitable initiators for the random copolymerization include isopropyl alcohol, hydrogen peroxide and solketal.

The copolymers may be blended with hydroxyl-group- containing compounds for use in preparing urethane foams.

Suitable hydroxyl-group-containing compounds include aliphatic glycols, dihydroxy aromatics, bisphenols, hydroxyl terminated polyethers, polyesters and polyacetals. The copolymer may comprise from about 2 to about 99, preferably about 2 to about 20, and most preferably 5 to about weight percent of the blend.

Preferably, the vinyl acetate based copolymer is prepared by the free radical process using a continuous process tubular reactor system. U.S. Patent No. 3,673,168 discloses a tubular reactor and continuous process for producing polymeric materials which are suitable for use in £032979 producing the vinyl acetate based copolymer of the present invention. U.S. Patent No. 3,673,168 is hereby incorporated by reference. Vinyl acetate monomer and the polyalkylene oxide containing either an allyl glycidyl ether or maleate unit are continuously fed into a tubular reactor in the presence of a solvent and an initiator. The vinyl acetate monomer is randomly polymerized with the polyalkylene oxide containing a maleate unit to yield the polyol in the tubular reactor. The polyol crude products so produced are continuously withdrawn from the tubular reactor mixture.

The following examples illustrate the nature of the invention.

In the following examples the materials used, were vinyl acetate (99% pure), butanol, ethyl alcohol, ethyl acetate from Aldrich Chemical Company; hydrogen peroxide from Dupont Chemical Company under the name Albone 50; and 2-propanol (purity of 99%) from American Scientific Products under the above name.

Example 1 The reactants shown in Table I were charged to a feeder vessel in the polymerization system described above.

Table I VAc 500 g Solketal initiated polypropylene oxide (PPO) (1500g/in)/maleate-PPO cap 100 g 50% B2O2 30 g IPA 340 g The reactants were added in no special order to a 2000 mL flask then poured into a stirred, water cooled feeder vessel. Nitrogen was bubbled through the reaction mixture. The contents were gravity fed into a diaphragm high pressure pump. The diaphragm pumps fed the reaction mixture at 450 psig and at a rate of 300 roL/hour into a heated (1550C) stainless steel coil. The slightly viscous liquid reaction product was collected at the end of the tubular reactor in a collector vessel. The volatiles were stripped off using a rotary evaporator. The resulting viscous oil was dissolved in ethyl acetate and neutralized to pH 8 with aqueous sodium bicarbonate. The organic layer was extracted, then washed with brine. The organic layer was collected and dried over sodium sulfate to give a 31 percent yield of product, OH# 41.5, % H20 = 0.15%.

The vinyl acetate based copolymer prepared in Example I was soluble in polyethers and was suitable for use in preparing polyurethanes.