Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-02-14
2003-05-13
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S245000, C510S268000, C510S214000, C510S417000, C510S505000, C526S212000, C526S318600, C526S089000, C526S194000, C526S204000, C526S208000, C526S209000, C526S213000, C526S217000, C526S220000, C526S222000
Reexamination Certificate
active
06562779
ABSTRACT:
The present invention relates to emulsifiable waxes, comprising copolymers of
from 90 to 95% by weight of ethylene,
from 4 to 10% by weight of one or more C
3
-C
12
alkenecarboxylic acids, and
from 0 to 1.2% by weight of one or more tertiary esters of the corresponding C
3
-C
12
alkenecarboxylic acids,
where the wax has a cinematic melt viscosity of from 800 to 3000 mm
2
/s, measured at 120° C.
The invention further relates to a process for preparing the novel emulsifiable ethylene polymers, to emulsions comprising the novel ethylene polymers, to a process for preparing the emulsions from the novel ethylene polymers, and also to floor cleaners, car cleaners, leather cleaners and stone cleaners, and to coatings for surfaces made from wood, metal, paper, glass or from plastics, comprising aqueous emulsions of the novel emulsifiable waxes.
Emulsifiable ethylene polymers are of great interest industrially, since they can be used as low-cost floor cleaners or processing aids, for example. Other applications are hot-melt adhesives, for metals, ceramics, wood, glass, leather or plastics, and also adhesion promoters for coatings made from polyolefins or from rubbers, and additives for paints. The emulsifiable ethylene polymers known industrially are oxygen-containing ethylene polymers in which the oxygen can be introduced in two different ways:
by free-radical or Ziegler-Natta polymerization of ethylene, followed by oxidation of the resultant polyethylene waxes by air or peroxides, or by pure oxygen, or by mixtures of the same, giving what are known as oxidate waxes, or
by free-radical copolymerization of ethylene with acrylic acid or methacrylic acid or with hydrolyzable acrylates or with methacrylates, with malonates, or with vinyl carboxylates, such as vinyl acetate, under high-pressure conditions, again introducing oxygen functionalities into the polyethylene chain.
However, both processes have disadvantages industrially. The oxidation of a polyethylene reduces the molecular weight of the fundamental polyethylene chains, and this is disadvantageous for the hardness of the product. Finally, the production of oxidate waxes is always a two-stage process, requiring additional capital expenditure (cf.
Ullmann's Enyclopädie der technischen Chemie,
4th edition, key words: Wachse, Vol. 24, pp. 36 et seq., Thieme Verlag Stuttgart, 1977, for example).
It is in fact possible to copolymerize ethylene directly with acrylic acid. However, the direct use of acrylic acid as comonomer in industrial plants is undesirable, since acrylic acid is corrosive in those sections of the plant disposed to mechanical stress, for example compressors, feed pipes and valves.
If an ester hydrolysis step has to be inserted after the polymerization in preparing a polyethylene wax, the result is a two-stage process with the associated disadvantages of high capital expenditure requirement.
DE-A 25 24 274 describes a process for preparing polymers made from ethylene and tert-butyl acrylate or tert-butyl methacrylate, polymerizing in a reactor and giving the resultant ethylene-tert-butyl acrylate-acrylic acid terpolymer a thermal post-treatment in a second reaction zone. The thermal post-treatment cleaves a certain percentage of the ester groups. The polymers known from the literature have very good film properties and provide good film material. However, the terpolymers prepared are unsuitable as waxes.
It is also known that tert-alkyl esters of acrylic acid or methacrylic acid can be copolymerized with ethylene by a free-radical route. These esters can be hydrolyzed under acid or alkaline conditions, and can also be cleaved thermally.
U.S. Pat. No. 3,132,120 describes the preparation of ethylene-tert-butyl methacrylate copolymers followed by thermolysis at from 275 to 350° C. in the absence of a substantial amount of oxygen. This is a two-stage process which requires high capital expenditure.
DE-A 43 34 846 describes a process for preparing carboxyl-containing copolymers of ethylene, featuring subsequent thermolytic cleavage of the ester groups of tertiary alcohols at from 150 to 250° C. in the presence of sulfonic acids. The process is characterized by the substantial absence of initiators for free-radical reactions. This, too, is a two-stage process.
DE-A 42 19 129 describes a procedure for the copolymerization of ethylene with n-butyl acrylate or tert-butyl acrylate in a tubular reactor which is operated at different temperatures in the different reaction zones. This procedure can give copolymers with good film properties, but not emulsifiable waxes.
DE-A 29 37 239 describes a process for preparing copolymers of ethylene by copolymerizing ethylene with esters of unsaturated carboxylic acids, and, in a second step reacting these at from 40 to 75° C. with compounds conventionally used for ester hydrolysis, in particular with concentrated H
2
SO
4
. This second step consumes time and needs high capital expenditure. In addition, contaminated solvents are produced, and are expensive to purify or dispose of.
Finally, DE-A 17 70 777 describes a process for preparing waxy copolymers of ethylene, in which ethylene, C
3
-C
12
alkenecarboxylic acids, tert-alkyl esters of the relevant C
3
-C
12
alkenecarboxylic acids, and also isobutene, are copolymerized by a free-radical route at from 110 to 350° C. and at pressures of from 100 to 4000 atm. A preferred embodiment mentioned is polymerization in a tubular reactor, and the temperature profiles are described in detail. However, the waxy copolymers obtainable by way of this teaching no longer meet the requirements of today's markets. For example, depending on the embodiment they comprise excessive proportions, i.e. more than 1% by weight, of uncleaved ester groups, making the waxes tacky. In another embodiment of DE-A 17 70 777, the proportions of acrylic acid copolymerized are too low, giving unsatisfactory emulsifiability. Finally, there are embodiments in which the viscosity, for example that determined by way of the cinematic viscosity, is too low, so that performance characteristics deteriorate. For example, floor cleaners produced using low-viscosity waxes lack adequate hardness. Lastly, performance testing shows that the copolymers obtainable by the process disclosed in DE-A 17 70 777 are chemically inhomogeneous. This inhomogeneity, caused for example by the differences in comonomer contents of the different polymer molecules, becomes noticeable in a relatively high speck count.
The wax obtainable as in DE-A 17 70 777 can be post-treated by prolonged heating, but this risks degradation of the polymer chains, or else crosslinking of the polymer. Crosslinked polymers in turn give a high speck count in performance tests. It would also be possible to ensure chemical homogeneity by, for example, feeding tert-butyl acrylate into the tubular reactor at a very large number of locations. However, the high pressures make this procedure disadvantageous for technical and cost reasons. Either numerous very high-performance pumps are required or severe pressure loss would have to be accepted.
It is an object of the present invention, therefore,
to provide emulsifiable waxes comprising ethylene-tert-butyl acrylate-acrylic acid copolymers which have a very low speck count, have adequate viscosity, are not tacky and can be prepared under cost-effective conditions,
to provide a process for preparing the desired waxes,
to prepare aqueous emulsions from the desired waxes, and
from the emulsions of the emulsifiable waxes to prepare floor cleaners, car cleaners, leather cleaners and stone cleaners, and also coatings for surfaces made from wood, metal, paper, glass or from plastics.
We have found that this object is achieved and that the novel emulsifiable waxes can be obtained by copolymerizing ethylene and one or more tertiary esters of one or more C
3
-C
12
alkenecarboxylic acids, preferably tert-butyl acrylate, in a stirred high-pressure autoclave at an elevated temperature, thermally cleaving the ester group during this same step, and carrying out these operations at a s
Deckers Andreas
Ehle Michael
Gast Siegfried
Weber Wilhelm
Weiss Stefan
BASF - Aktiengesellschaft
Keil & Weinkauf
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