Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Patent
1998-03-03
2000-02-15
Gupta, Yogendra
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
510299, 510361, 510475, 510476, 510500, 521149, 525281, 526258, 526263, C08F12606, B01J 3920
Patent
active
060253177
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to porous polymers which are in powder form and contain N-vinylimidazole units, to a process for the preparation thereof by free-radical precipitation polymerization of N-vinylimidazoles, and to the use of the polymers as additive to phosphate-free and reduced phosphate detergents for inhibiting color transfer during the washing process.
2. Description of the Background
Polymers of 1-vinylimidazole are prepared, for example, by free-radical polymerization of 1-vinylimidazole in aqueous solution or in alcohols, cf. DE-A-2 814 287. To prepare high molecular weight or crosslinked polymers of 1-vinylimidazole it is possible to employ precipitation polymerization in benzene, cf. EP-A-0 162 388. The polymers result as crosslinked gels.
The use of copolymers of vinylimidazole and vinylpyrrolidone in detergent formulations of various composition is disclosed in EP-A-0 635 563 and EP-A-0 635 566. These copolymers are soluble in water. They are normally isolated by spray-drying aqueous solutions and are used in powder form to produce the detergents. In order to obtain the polymers from the aqueous solutions it is necessary to expend a large amount of energy to evaporate the water.
The older, not prior-published German Patent Application P 44 21 179.1 discloses the use of water-insoluble, crosslinked polymers which are in powder form and contain units of 1-vinylpyrrolidone and/or 1-vinylimidazoles as additive to detergents and cleaners to prevent color transfer during the washing process. The copolymers have a particle size of from 0.1 to 500 .mu.m.
The older, not prior-published DE Patent Application 19 519 328.5 discloses the preparation of crosslinked vinylimidazole/vinylpyrrolidone copolymers in surfactants and the use of the copolymer/surfactant mixtures obtainable in this way in detergents. The removal of the copolymers from the mixture with the surfactants, which are usually liquid or waxy, is very industrially complicated.
U.S. Pat. No. 3,689,439 discloses the preparation of crosslinked polyvinylpyrrolidones by polymerizing N-vinylpyrrolidone with suitable crosslinkers in the presence of free-radical polymerization initiators in aqueous solutions of electrolytes.
The electrolyte content is 5-80% by weight, based on water, and the electrolyte concentration must be high enough for phase separation to occur. This process results in relatively large, usually bead-like, hard particles with a smooth surface. Another disadvantage is that polymer deposits, which are difficult to remove, are formed on the inside wall of the vessel and on the stirrer.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved process for preparing fine-particle polymers which are in powder form and contain imidazole units.
We have found that this object is achieved by porous polymers which are in powder form and contain N-vinylimidazole units and which are obtainable by free-radical precipitation polymerization of ##STR2## where R.sup.1, R.sup.2 and R.sup.3 are identical or different and are H, C.sub.1 -C.sub.4 -alkyl, monomers of the formula ##STR3## where R.sup.4 and R.sup.5 are identical or different and are H, C.sub.1 -C.sub.4 -alkyl, or together form a ring of 3 to 5 methylene groups, N-vinyloxazolidone, N-vinyltriazole, 4-vinylpyridine N-oxide or mixtures of said monomers, monomers and ethylenic double bonds in aqueous solution which contains 0.5-30% by weight of at least one electrolyte and, based on the monomers employed, 0.5-80% by weight of at least one surfactant.
The invention also relates to a process for preparing the porous polymers which are in powder form and contain N-vinylimidazole units, wherein ##STR4## where R.sup.1, R.sup.2 and R.sup.3 are identical or different and are H, C.sub.1 -C.sub.4 -alkyl, monomers of the formula ##STR5## where R.sup.4 and R.sup.5 are identical or different and are H, C.sub.1 -C.sub.4 -alkyl, or together form a ring of 3 to 5 methylene groups, N-vinyloxazolidone, N-vinyltriazole,
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Boeckh Dieter
Rossler Gerhard
Schade Christian
Stein Stefan
BASF - Aktiengesellschaft
Garrett Dawn L.
Gupta Yogendra
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