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
2001-07-30
2003-01-14
Seidleck, James J. (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...
C525S273000, C525S391000, C526S204000, C526S292500
Reexamination Certificate
active
06506836
ABSTRACT:
The present invention relates to a process for preparing a reaction product (A) by reacting under free-radical conditions at least one free-radically reactable monomer (a) in the presence of at least one free-radical initiator and of a compound (I) as defined below in aqueous phase, to said reaction production per se, to a process for preparing a polymer using said reaction product, and to the use thereof in polymer dispersions.
The present invention is situated within the technical field of free-radical addition polymerization, having features typical of a living polymerization system, the process of the invention being able in principle to provide reaction products, or polymers, which can have a narrow molecular weight distribution (M
w
/M
n
). Furthermore, through an appropriate selection of monomers and, if desired, successive addition of various monomers, it is possible to produce both branched and unbranched homopolymers and copolymers, and also block copolymers. In this context the present invention relates not only to the polymer per se but also to a reaction product obtained in a first stage.
For a number of years there has been great interest in processes and process concepts that are suitable for preparing a large number of polymers and make it possible to prepare polymers of this kind having a predetermined structure, molecular weight and molecular weight distribution.
For instance, WO 98/01478 describes a process for preparing polymers in which the monomer to be reacted, which is selected in particular from vinyl monomers and acid derivatives having unsaturated groups, such as anhydrides, esters and imides of (meth)acrylic acid, for example, is reacted in the presence of a free-radical initiator and a thiocarbonylthio compound as chain transfer agent.
WO 92/13903 describes a process for preparing polymers having a low molecular weight by free-radical chain polymerization of one or more monomers in the presence of a group transfer agent, as defined therein, which has a C—S double bond. On the evidence of that document the compounds described therein having a C—S double bond act not only as chain transfer agents but also as growth regulators, so that in accordance with that document it is only possible to prepare polymers of low molecular weight in the presence of this compound.
A process for free-radical chain polymerization of unsaturated monomers in aqueous medium and in the presence of a macromonomer having a —CH
2
—C(X)═CH
2
end group is defined in WO 93/22351, which also defines X. On the evidence of the examples of that application, various (meth)acrylates or (meth)acrylic acid and, if desired, monomers such as styrene are reacted in each case under emulsion or suspension polymerization conditions.
WO 93/22355 relates to a process for preparing crosslinkable polymers using a macromonomer as described in WO 93/22351.
WO 96/15157 likewise describes a process for preparing polymers having a comparatively narrow molecular weight distribution, in which a vinyl monomer, as defined therein, is reacted with a likewise vinyl-terminated macromonomer in the presence of a free-radical initiator.
Furthermore, WO 98/37104 relates to the preparation of polymers of controlled molecular weight, including acrylate-based polymers, by free-radical polymerization of corresponding monomers using a chain transfer agent which is defined more closely therein and has a C—C double bond and radicals which activate that double bond in terms of the free-radical addition reaction of monomers.
A free-radical chain polymerization or copolymerization with an &ohgr;-unsaturated oligo(methyl methacrylate) with ethyl acrylate, styrene, methyl methacrylate, acrylonitrile and vinyl acetate as comonomers is described in a scientific article in J. Macromol. Sci.-Chem., A 23(7), 839-852 (1986).
It is an object of the present invention to provide a novel process for preparing a reaction product which can likewise be used, inter alia, as a macroinitiator and which can first itself be used as an emulsifier or disperser and with the aid of which it is also possible to react further free-radically homopolymerizable or copolymerizable monomers in order to obtain further polymers possibly differing in composition. It is a further object of the present invention to provide for specific adjustment of polymer properties and so to allow the diverse use of polymers thus adjusted which are obtainable by simple free-radical polymerization, in particular by preparing block structures by means of free-radical polymerization.
We have found that these objects can be achieved by the process of the invention for preparing a reaction product (A), comprising the following stage (i):
(i) reacting under free-radical conditions a reaction mixture comprising at least one free-radically reactable monomer (a) in the presence of at least one free-radical initiator and of a compound (I) of the formula:
in which R
1
to R
4
each independently of one another are hydrogen, a substituted or unsubstituted alkyl radical, cycloalkyl radical or aralkyl radical, or an unsubstituted or a substituted aromatic hydrocarbon radical, with the proviso that at least two of R
1
to R
4
are an unsubstituted or a substituted aromatic hydrocarbon radical in aqueous phase.
The invention further provides a reaction product (A) preparable by means of a process comprising the following stage (i):
(i) reacting under free-radical conditions a reaction mixture comprising at least one free-radically reactable monomer (a) in the presence of at least one free-radical initiator and of a compound (I) of the formula:
in which R
1
to R
4
each independently of one another are hydrogen, a substituted or unsubstituted alkyl radical, cycloalkyl radical or aralkyl radical, or an unsubstituted or a substituted aromatic hydrocarbon radical, with the proviso that at least two of R
1
to R
4
are an unsubstituted or a substituted aromatic hydrocarbon radical in aqueous phase.
Within the scope of the above process of the invention it is possible to use all free-radically reactable monomers as monomer (a). As monomer (a) it is preferred to use those free-radicaly homopolymerizable or copolymerizable compounds which include a hydrophilic group, such as, for example, a carboxyl group. With further preference, the monomers (a) comprise hydrophilic, free-radically homopoly-merizable or copolymerizable monomers, i.e. monomers whose solubility in water is greater than that of styrene. It is of course also possible for mixtures of different hydrophilic monomers, and mixtures of at least one hydrophilic monomer and at least one hydrophobic monomer, to be present in the reaction mixture of stage (i). Specific representatives of monomers (a) are:
methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, methacrylonitrile, alpha-methylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate (all isomers), butyl acrylate (all isomers), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl acrylate, acrylonitrile, styrene, functionalized methacrylates; acrylic acids and styrenes, selected from glycidyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate (all isomers), hydroxybutyl methacrylate (all isomers), diethylaminoethyl methacrylate, triethylene glycol methacrylate, itaconic anhydride, itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate (all isomers), diethylaminoethyl acrylate, triethylene glycol acrylate, methacrylamide, N-tert-butylmethacrylamide, N-n-butylmethacrylamide, N-methylolmethacrylamide, N-ethylolmethacrylamide, N-tert-butylacrylamide, N-butylacrylamide, N-methylol-acrylamide, N-ethylolacrylamide, vinylbenzoic acid (all isomers), diethylaminostyrene (all isomers), alpha-methylvinylbenzoic acid (all isomers), diethylamino-alpha-methylstyrene (all isomers), paramethylstyrene,
Bendix Maximilian
Bremser Wolfgang
Christie David
Paulus Wolfgang
Raether Roman Benedikt
Asinovsky Olga
BASF - Aktiengesellschaft
Keil & Weinkauf
Seidleck James J.
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