Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1990-07-30
1992-04-28
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526281, C08F 2400
Patent
active
051090880
DESCRIPTION:
BRIEF SUMMARY
FIELD OF ART
This invention relates to a resin composition for cement and use thereof
TECHNICAL BACKGROUND
In the fields of civil engineering and construction, an emulsion of a synthetic polymer called an adhesion promoter is thinly coated on a concrete surface as a primer, or blended with cement mortar, etc., in order to improve workability, adhesion, physical strength, contraction, water absorptivity, etc., of cement paste, cement mortar, etc. As a proposal for improvement of adhesion of cement mortar, there is a process which comprises pre-applying a synthetic polymer emulsion to a surface in order to promote the adhesion of mortar, as is disclosed in Japanese Patent Publication No. B-Sho-44-18757.
Even if an emulsion of a synthetic polymer was used on a concrete surface or in cement mortar according to the above prior technique, the general performances of workability, adhesion, alkali resistance, weatherability, etc., are not sufficiently well-balanced. An ethylene-vinyl acetate-based emulsion has good hydrophilic nature and hence has good compatibility with cement and excellent workability. However, it has a defect that the polymer is susceptible to hydrolysis due to alkalinity of cement.
A styrene-butadiene-rubber-based latex has good alkali resistance. However, it has poor hydrophilic nature and hence has poor compatibility with cement. For this reason, its workability is inferior. Further, since it has a double bond derived from butadiene, its weatherability is poor.
On the other hand, an acrylic emulsion has high hydrophilicity, and therefore has good compatibility with cement. Further, it is excellent in alkali resistance and weatherability. However, its difficulty is that since none of its adhesion to a concrete surface, dry contraction and freeze and thaw stabilities are insufficient, the range of its application is naturally limited.
DISCLOSURE OF THE INVENTION
The present inventors have focused on the excellent workability, alkali resistance and weatherability of an acrylic emulsion, and made a diligent study to improve the defects of this emulsion, dry contraction and adhesion. As a result, they have found that the above defects can be overcome by using a polymer obtained by graft-copolymerization of a dicyclopentadiene derivative, an unsaturated epoxy ester, an .alpha.,.beta.-unsaturated monocarboxylic acid and an ethylenically unsaturated monomer according to an emulsion polymerization method, which finding has led to this invention.
BEST MODE FOR CARRYING OUT THIS INVENTION
That is, this invention relates to a resin composition for cement, which comprises a polymer obtained by the emulsion polymerization of
5 to 50% by weight of a dicyclopentadiene derivative (A) represented by the following general formula ##STR2## (wherein R represents hydrogen or a methyl group, R' represents a divalent organic group, and n represents 0 or a positive integer),
1 to 50% by weight of an unsaturated epoxy ester (B),
0.5 to 5% by weight of an .alpha.,.beta.-unsaturated monocarboxylic acid (C), and
30 to 90% by weight of an ethylenically unsaturated monomer (D) copolymerizable with the components (A), (B) and (C) the above components being selected so that their total weight is 100% by weight.
Examples of the dicyclopentadiene derivative represented by the above general formula include dicyclopentadienyloxyalkyl acrylates or their corresponding methacrylates such as dicyclopentadienyl (meth)acrylate, dicyclopentadienyloxyethyl (meth)acrylate, dicyclopentadienyloxybutyl (meth)acrylate, dicyclopentadienyloxypropyl (meth)acrylate, etc., dicyclopentadienyloxyethoxyethyl (meth)acrylate, and the like. Among these, preferably usable are dicyclopentadiene derivatives of the above general formula wherein n is 1 to 2.
The dicyclopentadiene derivative represented by the above general formula is an already known compound, and can be produced by a process described in Japanese Patent Publication No. B-Sho-61-43337.
For example, the compound can be produced by reacting alkylene glycol or oxyalkylene glycol wit
Ohwada Takeo
Tanaka Kazuyuki
Hitachi Chemical Company Ltd.
Schofer Joseph L.
Walker Alex H.
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