Bleaching and dyeing; fluid treatment and chemical modification – Treatment of hides – skins – feathers and animal tissues – Tanning
Reexamination Certificate
1997-09-15
2002-01-08
Metzmaier, Daniel S. (Department: 1712)
Bleaching and dyeing; fluid treatment and chemical modification
Treatment of hides, skins, feathers and animal tissues
Tanning
C008S094330, C427S389000
Reexamination Certificate
active
06336942
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aqueous solutions or emulsions of copolymers of monoethylenically unsaturated dicarboxylic acids or the anhydrides thereof and branched oligomers or polymers and the use of these solutions or emulsions as leather assistants and dispersants for pigments. Since some of the copolymers described are novel substances, the present invention furthermore relates to these copolymers.
2. Description of the Background
German Patent 2,629,748 (1) discloses the use of copolymers of linear C
10
-C
30
-olefins and maleic anhydride, which copolymers have been hydrolyzed with alkali metal bases or amines, for plumping and fatliquoring leather and skins. The hydrolyzed copolymers can also be reacted with alkali metal bisulfite. Since the copolymers are prepared in organic solvents and the solvents are not removed, the aqueous copolymer emulsions prepared therefrom contain considerable amounts of organic solvents, for example xylene or dodecylbenzene. Although such emulsions are recommended for fatliquoring leather and skins, their content of organic solvents makes them virtually useless for leather production.
EP-A 412 389 (2) discloses the use of aqueous solutions or emulsions of partially neutralized copolymers of maleic anhydride with C
8
-C
40
-olefins for rendering leathers and skins water repellent. Examples of olefin components are oct-1-ene, diisobutene, dec-1-ene, dodec-1-ene, tetradec-1-ene, hexadec-1-ene and cyclooctene.
EP-A 486 608 (3) discloses the use of copolymers based on long-chain alkyl vinyl ethers and ethylenically unsaturated dicarboxylic anhydrides for rendering leather and skins water repellent.
EP-A 579 267 (4) discloses emulsions of water-insoluble amphiphilic copolymers, for example based on primary alkenes and maleic anhydride, which can be used for the treatment of tanned leather.
When used in practice, the prior art polymeric assistants for the water repellent treatment and also for the fatliquoring and retanning of leather often have the serious disadvantage that they penetrate only into those layers of the leather which are close to the surface. The insufficient penetration of these polymeric assistants through the leather cross-section results in the leathers produced therewith frequently having deficiencies with regard to the achievable body, softness, color depth and water repellency. Thus, water can penetrate substantially unhindered at cut edges, seams and tears and in areas of mechanically caused surface damage.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide suitable polymer-based compositions which permit good penetration through the leather cross-section.
We have found that this object is achieved by aqueous solutions or aqueous emulsions of copolymers, which are obtainable by copolymerization of
(a) from 20 to 95 mol % of at least one monoethylenically unsaturated C
4
-C
12
-dicarboxylic acid or the anhydride thereof with
(b) from 5 to 80 mol % of at least one branched oligomer or polymer which has a vinyl, vinylidene or alkylvinylene terminal group and is of at least 9 carbon atoms and
(c) from 0 to 50 mol % of at least one further monoethylenically unsaturated compound which is copolymerizable with the monomers (a) and (b).
DETAILED DESCRIPTION OF THE INVENTION
The stated copolymers are used as aqueous solutions or aqueous emulsions containing usually from 0.5 to 70, in particular from 1 to 60, preferably from 3 to 35, % by weight, based on the total amount of the solutions or emulsions, of these copolymers in untreated or in solvolyzed and/or neutralized form (solids content).
Some of the copolymers on which the novel aqueous solutions or aqueous emulsions are based are known in principle, for example from WO-A 90/03359 (5) and German Patent Application P 43 30 971.2 (6); there, however, the copolymers are recommended in oil-soluble form as fuel and lubricant additives.
Some or all of the anhydride groups present in the copolymer can be solvolyzed with compounds containing hydroxyl functional groups or with amines. The untreated polymers or polymers solvolyzed, ie. esterified, amidated or imidated, with alcohols or amines are, as a rule, then subjected in the aqueous medium to at least partial neutralization at the carboxyl groups which are present or which are formed in the solvolysis. The solution or emulsion obtained can be used mainly as a retanning agent, a fat-liquor or a water repellent for leather.
The aqueous solutions or emulsions can also be prepared using up to 40%, based on the amount of copolymer, of emulsifiers or protective colloids or said emulsifiers or protective colloids may be added to them after their preparation. This results in excellent fatliquoring and retanning properties for leather in combination with good penetration.
Suitable monomers (a) are monoethylenically unsaturated carboxylic acids and their anhydrides of 4 to 12, in particular 4 to 6, carbon atoms, especially maleic acid, itaconic acid, citraconic acid, mesaconic acid, fumaric acid, maleic anhydride, itaconic anhydride, citraconic anhydride, methylenemalonic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride and 2-methyl-1,3,6-tetrahydrophthalic anhydride and mixtures of these with one another. Maleic anhydride is preferred.
Suitable monomers (b) are branched oligomers or polymers of 9 to, usually, 350, preferably 10 to 140, in particular 11 to 70, especially 12 to 30, carbon atoms, which are prepared by oligomerization or polymerization of linear or branched olefins or olefin mixtures and contain a copolymerizable terminal group in the form of a vinyl, vinylidene or alkylvinylene group. These terminal groups can be characterized by the following general formulae:
Branched means that the oligomer or polymer chain carries alkyl side chains, in particular C
1
-C
40
-alkyl side chains, especially C
1
-C
24
-alkyl side chains, very particularly preferably methyl and C
5
-C
16
-alkyl side chains at more or less regular intervals. As a rule, there are from 0.3 to 8, in particular from 0.7 to 6, especially from 1 to 5, alkyl side chains per 10 carbon atoms in the main chain, and 1 carbon atom in the main chain may carry one or two alkyl side chains.
Examples of suitable linear or branched olefins or olefin mixtures for the preparation of the monomers (b) are propene, but-1-ene, isobutene, hex-1-ene, 2,4,4-trimethylpent-1-ene, 2,4,4-trimethylpent-2-ene, C
8
-C
10
-&agr;-olefin, dodec-1-ene, C
12
-C
14
-&agr;-olefin, 1-tetradecene, 1-hexadecene, 1-octadecene, C
20
-&agr;-olefin, C
22
-&agr;-olefin, C
24
-&agr;-olefin and a mixture of C
20
-C
24
-&agr;-olefin, C
24
-C
28
-&agr;-olefin, C
30
-&agr;-olefin or C
40
-&agr;-olefin. Mixtures of ethene as a component with the mixture may also be used, for example an ethene/butene mixture or an ethene/hexene mixture. Functionalized olefins which carry, for example, amino, hydroxyl, carboxyl or ester groups, aryl radicals, further C—C double bonds or cyclic saturated or unsaturated alkyl radicals may also be used, alone or as a mixture, for the preparation of tbe branched oligomers or polymers (b).
Examples of branched oligomers or polymers (b) are oligopropene, oligohexene, oligo(hexene/ethene), oligooctadecene and polyisobutene, for example polyisobutene having a number average molecular weight of 1000, 1300 or 2300.
The branched oligomers or polymers (b) can as a rule be prepared from the stated starting olefins by conventional polymerization methods using metal complexes, for example metallocene complexes, as catalysts or by means of known cationic polymerization methods.
Suitable monomers (c) are all those monomers which are copolymerizable with monomers (a) and (b).
These are, for example, linear 1-olefins (&agr;-olefins) of 2 to 40, preferably 8 to 30, carbon atoms, such as decene, dodecene, octadecene and industrial m
Danisch Peter
Denzinger Walter
Dix Johannes Peter
Kistenmacher Axel
Kneip Michael
BASF - Aktiengesellschaft
Metzmaier Daniel S.
LandOfFree
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