Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1997-03-28
1998-04-14
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524458, 526264, C08F 216, C08F 2606
Patent
active
057391955
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for preparing aqueous solutions of poly(N-vinyl-.di-elect cons.-caprolactam) by polymerizing N-vinyl-.di-elect cons.-caprolactam in an aqueous medium in the presence of polymerization initiators.
N-Vinyl-.di-elect cons.-caprolactam can be prepared for example in an organic solvent or else in water in the presence of free-radical polymerization initiators. The bulk polymerization of N-vinylcaprolactam cannot be realistically contemplated in industry, since the polymerization reaction is difficult to control and the viscosity of the reaction mixture increases rapidly as the polymerization proceeds, so that it is no longer possible to ensure complete mixing. True, the polymerization of N-vinylcaprolactam in an organic solvent is technically feasible, but the organic solvent would have to be removed before any further processing of the polymer. Aqueous solutions of poly(N-vinyl-.di-elect cons.-caprolactam) are of particular interest from an application standpoint. However, the polymerization of N-vinyl-.di-elect cons.-caprolactam in water is not straightforward because of the thermoreversible solution behavior of the monomer. Vinylcaprolactam monomer has a melting point of 34.degree. C. and is virtually insoluble in cold water, whereas the polymer is readily soluble in cold water, but insoluble in water above the lower critical dissolution temperature of about 35.degree. C. An obvious compromise for the polymerization would be to conduct the reaction at a temperature above the melting point of N-vinylcaprolactam in the manner of an oil-in-water emulsion polymerization. To prepare aqueous polyvinylcaprolactam solutions in this way, the reaction mixture obtained in the oil-in-water emulsion polymerization would have to be stirred with water for a period from several hours to days--especially if the aqueous solution is to have a polymer content of more than 10% by weight--until the viscous or glassy, water-surrounded polymer material turned into a homogeneous solution free of gel particles.
Makromol. Chem. 191 (1990), 169-184, discloses a microemulsion process for polymerizing N-vinyl-.di-elect cons.-caprolactam in water in the presence of from about 20 to 50% by weight, based on the monomer, of a dialkyl sulfosuccinate as emulsifier. The disadvantage of such microemulsions is the high emulsifier content.
Poly(N-vinyl-.di-elect cons.-caprolactam) is used for example as a polymer additive in lubricant compositions, as a protective colloid and as a binder for nonwovens, cf. Ullmann's Encyclopedia of Industrial Chemistry, Volume A 21, page 754 (1992). DE-B-1 240 812 and DE-A-2 039 079 disclose the use of poly(N-vinylcaprolactam) and mixtures of polyvinylcaprolactam and at least one alkali metal or ammonium salt of a copolymer of at least one acrylic ester, an .alpha.,.beta.-monoethylenically unsaturated carboxylic acid and methyl methacrylate as an adhesive for textile material in screen printing. According to U.S. Pat. No. 5,126,124, polyvinylcaprolactam is used in hairsprays. The fact that polyvinylcaprolactam has a thermoreversible solution behavior in water with a lower critical dissolution temperature of about 35.degree. C. makes this polymer interesting for use as an opacifier in automatic shading systems, cf. DE-A-1 285 124.
EP-A-0 526 800 discloses polymers of ethylenically unsaturated compounds containing at least one covalent nitrogen atom in the molecule. They are prepared by free-radical polymerization of the monomers in the presence of monosaccharides, oligosaccharides, polysaccharides or derivatives thereof in aqueous systems. The polymers are useful as film-forming conditioners in cosmetic formulations and as stabilizers for perfumes and perfume oils.
It is an object of the present invention to provide a relatively rapid process for preparing homogeneous aqueous solutions of polyvinylcaprolactam.
We have found that this object is achieved by a process for preparing an aqueous solution Of poly(N-vinyl-.di-elect cons.-caprolactam) by polymerizing N-vinyl-.di-el
REFERENCES:
patent: 5126124 (1992-06-01), Tazi et al.
patent: 5239053 (1993-08-01), Tseng et al.
Hydrophobic Water-Soluble Polymers, 1,Michael Eisele, Walther Burchard Dilute Solution Properties of Poly(1-vinyl-2-piperidone)and poly(N-vinylcaprolactam) Makromol. Chem. 191, 169-184, 1990.
Ullmann's Encyclopedia of Industrial Chemistry Fift, Completely Revised Edition, vol. A21: Plastics, Properties and Testing to Polyvinyl Compounds Editors: Barbara Elvers, Stephen Hawkins, Gail Schulz pp. 754-756.
KHIM, ATSETILENA, 1968 MOSCOW SU, Seiten 382-5, SIDEL 'KOVSKAYA, IBRAMIGOV, ASKAROV 'synthesis of graft copolymers of cellulose and poly(n-vinyllactams) siehe Seite 382--Seite 5.
Kerber Michael
Kroker Jorg
Schneider Reinhard
Schupp Eberhard
BASF - Aktiengesellschaft
Cheng Wu C.
Schofer Joseph L.
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