Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1996-08-21
1998-06-30
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526229, 5263184, C08F 200
Patent
active
057735417
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the preparation of copolymers of vinyl esters and monoethylenically unsaturated carboxylic acids by free-radical copolymerization in aqueous medium in the presence of initiators and in the presence or absence of regulators and to the use of the copolymers as additive to detergents and cleaners.
U.S. Pat. No. 3,268,491 discloses a process for preparing copolymers of vinyl acetate and monoethylenically unsaturated dicarboxylic acids by copolymerization of the monomers in aqueous medium at pH 3-6 in the presence of redox catalysts. Persulfates are preferably used as oxidizing component of the redox system, while sulfites or thiosulfates are used as reducing component. The oxidizing component is in this case always used in a molar excess over the reducing component. Alternating copolymers are obtained.
EP-A-0 441 022 discloses copolymers of monoethylenically unsaturated dicarboxylic acids and monoethylenically unsaturated monocarboxylic acids prepared by copolymerization of 3-25% by weight of at least one monoethylenically unsaturated dicarboxylic acid and 75-97% by weight of at least one monoethylenically unsaturated monocarboxylic acid, with or without ethylenically unsaturated monomers without carboxyl groups, in the presence of water-soluble polymerization initiators, copper salts as polymerization moderators and a base. Vinyl acetate is also mentioned as ethylenically unsaturated monomer without carboxyl groups but is not proven by examples. Under the polymerization conditions described, however, there is observed to be great decomposition of the vinyl acetate and the formation of vinyl acetate homopolymers.
U.S. Pat. No. 3,887,480 describes the preparation of terpolymers from 35-70 mol % of maleic acid, 20-45 mol % of vinyl acetate and 2-40 mol % of acrylic acid in aqueous medium in the presence of 18-40% by weight of persulfate and of bisulfite, with persulfate being used in a molar excess over bisulfite.
GB-A-923 850 discloses the preparation of latices having a polymer content of 30-55% by weight by polymerizing vinyl acetate with 0.5-3.0% by weight, based on the monomer mixture, in the presence of redox catalysts and wetting agents in aqueous emulsion at below 50.degree. C.
In the processes described above, the ethylenically unsaturated carboxylic acids are at least partially neutralized because otherwise excessive decomposition of the vinyl acetate would occur during the polymerization.
It is an object of the present invention to provide a process for preparing copolymers of vinyl esters of saturated carboxylic acids having at least 2 carbon atoms, in which the decomposition of the vinyl esters during the polymerization is not as serious as in known processes.
We have found that this object is achieved by a process for preparing copolymers of vinyl esters and monoethylenically unsaturated carboxylic acids by free-radical copolymerization in aqueous medium in the presence of initiators and in the presence or absence of regulators, which comprises copolymerizing at least 2 carbon atoms and without monomers and/or ethylenic double bonds in the molecule, with a reducing action and of 0.05-30% by weight, based on the monomers, of at least one surface-active agent.
Compared with known processes for preparing copolymers of vinyl esters, the advantages of the process according to the invention are that the decomposition of the vinyl esters during the copolymerization is very greatly diminished, that the resulting copolymers are kept in dispersion or in solution, and that the vinyl esters are incorporated in the resulting copolymer in the same proportion as in the monomer mixture.
Suitable vinyl esters are derived from saturated carboxylic acids having at least two carbon atoms, e.g. vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl palmitate, vinyl stearate and vinyl laurate. Thus the vinyl esters can be based, for example, on saturated carboxylic acids having 2-18 carbon atoms. It is possible to use in the copolymerization one or a mixture of at leas
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patent: 3530080 (1970-09-01), Kirkwood
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Baur Richard
Boeckh Dieter
Denzinger Walter
Funhoff Angelika
Kistenmacher Axel
BASF - Aktiengesellschaft
Sarofim N.
Schofer Joseph L.
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