Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-06-10
2001-06-19
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S326900, C525S328200
Reexamination Certificate
active
06248836
ABSTRACT:
The invention relates to amphiphilic graft polymers based on graft bases containing N-vinylcarboxamide units, to processes for their preparation and to their use as strength enhancers for paper, as fixing agents for water-soluble and water-insoluble contaminants in papermaking, as an additive to detergents and cleaning products, as dispersants for organic and inorganic pigments, dyes, concrete and crop protection agents, as coating material for fertilizers and crop protection agents, as floor care agents, as a protective colloid for aqueous polymer dispersions, as thickeners for cosmetics formulations, as conditions for skincare compositions and as a constituent of cosmetic hair preparations and of cosmetic preparations for oral care.
DE-A-27 11 458 discloses a method of improving the keeping properties of a protective antidecay film, over which film a protective coating is applied by applying a composition comprising a polymer that has been prepared by polymerizing at least one vinyl monomer from the group consisting of methacrylates, acrylates, acrylonitrile, styrene, &agr;-methylstyrene and vinyl acetate in the presence of a hydrophilic polymer from the group consisting of polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone and polyvinylamine. The graft polymers are prepared by free-radically initiated poly-merization of the monomers in the presence of said polymers in an organic solvent such as toluene.
U.S. Pat. No. 4,238,579 discloses copolymers comprising units of both vinylamine and styrene. They are prepared by free-radically initiated copolymerization of vinylacetamide and styrene in bulk or in solution with subsequent partial or complete hydrolysis of the amide groups of the copolymerized N-vinylacetamide to form amino groups. The polymers are used, for example, as coating materials or as hardeners for epoxy resins.
WO-A-95/25759 discloses graft polymers of which the graft base is a polymer containing in each case at least 5% by weight of units of the formulae
and/or
where R
1
and R
2
are H or C
1
- to C
6
-alkyl. Monoethylenically unsaturated monomers are grafted onto the graft base in a weight ratio of from 100:1 to 1:100.
The monomers grafted onto the graft base are preferably from the group consisting of N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, acrylic acid, methacrylic acid, acrylamide, acrylonitrile and vinyl acetate. The graft copolymers are used, for example, as dispersants for pigments, as an additive to detergents and cleaning products, as strength enhancers for paper and as materials for soil conditioning and fertilizer compaction.
Where the above-described graft copolymers are employed in papermaking, their effectiveness, and especially their fixing effect for soluble or insoluble papermaking contaminants, still leave something to be desired.
It is an object of the present invention to provide new graft polymers which especially in papermaking fix soluble and insoluble contaminants, such as pitch, effectively on the paper sheet that is formed.
We have found that this object is achieved, in accordance with the invention, with amphiphilic graft polymers based on graft bases containing N-vinylcarboxamide units, the amphiphilic graft polymers being obtainable by free radical polymerization of monomer mixtures of
(a) styrene, a C
1
- to C
2
-alkylstyrene and/or vinyltoluene with or without
(b) other monoethylenically unsaturated monomers copolymerizable therewith
onto a polymer comprising at least 5% by weight of units of the formula
with or without units of the formula
as graft base, in a weight ratio of from 1:99 to 99:1, and subsequent 5-100% cleavage of the formyl groups from the graft polymers, with the formation of amino groups.
The present invention also provides a process for preparing the abovementioned amphiphilic graft polymers, which involves subjecting monomer mixtures of
(a) styrene, a C
1
- to C
2
-alkylstyrene and/or vinyltoluene with or without
(b) other monoethylenically unsaturated monomers copolymerizable therewith
to free-radical polymerization in the presence of polymers containing at least 5% by weight of N-vinylformamide units as graft base, in a weight ratio of from 1:99 to 99:1, and, after the graft polymerization, cleaving off from 5 to 100% of the formyl groups from the N-vinylformamide units, with the formation of amino groups.
The amphiphilic graft polymers described above are used with particular advantage as fixing agents for soluble and colloidal contaminants in papermaking. Examples of such contaminants are present in the pulp in the form of humic acids, ligninsulfonate, silicic acids or wood extract. The amphiphilic graft copolymers are used for fixing insoluble, lipophilic/hydrophobic contaminants, known as stickies or white pitch. They are also suitable as dispersants in the paper coating plant. Among the applications described above, their use as a protective colloid for acrylate, styrene and butadiene dispersions and as an additive to detergents and cleaning products is also of interest.
The graft base comprises polymers at least 5% by weight of whose copolymerized units are of the formula I above. Other suitable graft bases are hydrolyzed poly-N-vinylformamides which are obtainable by treating poly-N-vinylformamides with acids or bases and which in addition to the units of the formula I include units of the formula
The graft base can if desired contain up to 95% by weight of units of the formula II.
The units of the formula I are based on N-vinylformamide as the monomer. For polymer preparation these monomers can be used alone, in a mixture with one another, for example mixtures of N-vinylformamide and N-vinylacetamide, or together with other copolymerizable monomers. Processes for preparing such homo- and copolymers with other monomers are known, cf. EP-B-0 071 050, EP-B-0 215 387, EP-B-0 251 182, EP-A-0 528 409 and EP-A-0 337 310.
Examples of suitable other monomers which can be copolymerized with N-vinylformamide are monoethylenically unsaturated carboxylic acids with 3 to 8 carbons, such as acrylic, methacrylic, dimethacrylic, ethacrylic, maleic, citraconic, methylenemalonic, allylacetic, vinylacetic, crotonic, fumaric, mesaconic and itaconic acid. From this group of monomers it is preferred to use acrylic, methacrylic or maleic acid or mixtures thereof. The monoethylenically unsaturated carboxylic acids can be used in the form of free acid and—if in existence—the anhydrides, or in partially or completely neutralized form, in the copolymerization. To neutralize these monomers it is preferred to use alkali metal bases or alkaline earth metal bases, ammonia or amines, for example sodium hydroxide solution, potassium hydroxide solution, sodium carbonate, potash, sodium hydrogen carbonate, magnesium oxide, calcium hydroxide, calcium oxide, gaseous or aqueous ammonia, triethylamine, ethanolamine, diethanolamine, triethanolamine, morpholine, diethylenetriamine or tetraethylenepentamine.
Examples of other suitable comonomers for preparing the graft base are the esters, amides and nitriles of the abovementioned carboxylic acids, for example methyl and ethyl acrylates, methyl and ethyl methacrylates, hydroxyethyl, hydroxypropyl and hydroxybutyl acrylates, hydroxyethyl, hydroxypropyl and hydroxyisobutyl methacrylates, hydroxyisobutyl acrylate, monomethyl maleate, dimethyl maleate, monoethyl maleate, diethyl maleate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylamide, methacrylamide, N,N-dimethylacrylamide, N-tert-butylacrylamide, acrylonitrile, methacrylonitrile, dimethylaminoethyl acrylate, diethylamino acrylate, diethylaminoethyl methacrylate, and also the salts of the latter monomers with carboxylic acids or mineral acids, and the quaternized products.
Other suitable copolymerizable monomers are acrylamidoglycolic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate and acrylamidomethylpropanesulfonic acid and also monomers containing phosphonic acid groups, such as vin
Meixner Hubert
Negele Anton
Rubenacker Martin
Utecht Jens
BASF - Aktiengesellschaft
Mullis Jeffrey
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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