Patent GB-795262-A (GB)
Title: Di-acid di-esters derived from maleic anhydride and copolymers thereof with olefinic compounds
IPC: C08G63/676
Filed: 1955-11-28
Abstract: The invention comprises an alkylene polyoxyalkylene dihydrogen dimaleate which is the product of the additive reaction of one mol. proportion of a polyalkylene glycol having a plurality of ether linkages with two mol. proportions of maleic anhydride, the reaction being characterized by opening of the anhydride ring and joining of the glycol with only one carboxy portion of each maleic residue.  The products are of the type HOOC-CH = CH-COO-alkylene (oxyalkylene)nO-CO-CH = CH-COOH, wherein n is an integer greater than 1 and may be obtained by heating one mol. proportion of a polyalkylene glycol with two mol. proportions of maleic anhydride, the reaction temperature being preferably within the range of 130 DEG to 160 DEG  C.  The product is then blown at 130 DEG  to 160 DEG  C. with carbon dioxide or nitrogen for 1 to 2 hours to remove volatile materials and unreacted maleic anhydride, a clear syrupy liquid being obtained.  The polyalkylene glycols are preferably those having number-average molecular weights in the range of about 300 to about 1200 but polyglycols having molecular weights as high as 4000 may be used.  Examples are given for the production of the dimaleates of polyethylene glycol 600 and polypropylene glycol 750 the reaction being carried out in each case by heating a mixture of the polyglycol under reflux with maleic anhydride in the presence of benzene and of zinc chloride as catalyst.  It is stated that the diacid dimaleates of polyethylene glycol 400 and polyethylene glycol 300 respectively may be obtained in a similar manner.  The products may be copolymerized with an olefinically unsaturated comonomer or they may be blended with an unsaturated maleic alkyd polyester and the blend copolymerized with an olefinic comonomer (see Group IV (a)).ALSO:The invention comprises an alkylene polyoxyalkylene dihydrogen dimaleate which is the product of the additive reaction of one mol. proportion of a polyalkylene glycol having a plurality of ether linkages with two mol. proportions of maleic anhydride, the reaction being characterized by opening of the anhydride ring and joining of the glycol with only one carboxy portion of each maleic residue.  The invention also comprises a copolymer of the dimaleate product with an olefinically unsaturated comonomer, and a resinous interpolymer of the dimaleate product, an unsaturated maleic alkyd polyester, and an olefinically unsaturated comonomer.  The polyalkylene glycol is preferably one having a number-average molecular weight in the range of about 300 to about 1200 but one having a molecular weight as high as 4000 may be used.  The dimaleate product has the structure HOOC.CH = CH.COO-alkylene (oxyalkylene)nO-CO.CH = CH.COOH wherein n is an integer greater than 1.  The dimaleate may be copolymerized with olefinic comonomer such as styrene, vinyl toluene and other alkyl styrenes; vinyl esters, e.g. vinyl acetate and vinyl butyrate; acrylic and methacrylic esters such as ethyl acrylate, butyl acrylate and methyl methacrylate; vinyl pyridine and alkyl vinyl pyridines, e.g. 2-vinyl pyridine, 5-ethyl-2-vinyl pyridine, 2-methyl-5-vinyl pyridine; N-vinylimides, e.g. N-vinylphthalimide, N-vinyl-pyrrolidone and allyl esters such as diallyl phthalate, diallyl benzenephosphonate and triallyl cyanurate.  In examples: (1) polyethylene glycol 600 dimaleate is obtained by refluxing polyethylene glycol 600 and maleic anhydride in the presence of benzene and zinc chloride and then adding a small amount of p-tert.-butylcatechol and blowing the reaction mixture with carbon dioxide gas or nitrogen for 1 to 2 hours at 140-160 DEG  C. The syrupy liquid product is then blended with styrene in various proportions and a free radical polymerization catalyst comprising a 1 : 1 blend of benzoyl peroxide and tricresyl phosphate and cured in three stages-2 hours at 70 DEG  C., 1 hour at 90 DEG  C. and 1 hour at 110 DEG  C. in succession; (2) as in (1) except that polypropylene glycol 750 is used as the polyglycol; (3) the diacid maleates of polyethylene glycols 600, 400 and 300 are prepared by a process as in (1) and mixed with various proportions of styrene and diallyl phthalate respectively and cured as in (1); (4) the dimaleate of polyethylene glycol 600 is copolymerized in the presence of benzoyl peroxide with styrene, diallyl phthalate, vinyl toluene, methyl methacrylate, vinyl acetate, diallyl benzene phosphonate, triallyl cyanurate, 2-methyl-5-vinyl - pyridine, N - vinyl - phthalimide, and N-vinyl pyrrolidone respectively. Curing is effected in each case for 15 hours at 55 DEG  C. plus 1 hour at 110 DEG  C.; (5) an unsaturated alkyd is prepared by heating a mixture of one mol. maleic anhydride, one mol. phthalic anhydride and 2.14 mols. propylene glycol and the product is then mixed with styrene and the mixture polymerized in the presence of benzoyl peroxide with the polyglycol dimaleate products of (1) and (2) respectively using various proportions of the alkyd polyester, styrene and dimaleate.  The polymerization is effected in three stages-2 hours at 70 DEG  C., 1 hour at 90 DEG  C. and d1 hour at 110 DEG  C. Tables are given to show the physical properties, including tensile strength, Young's modulus, and impact strength, of the polymeric products of each example.