JPH0525899B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a synthetic resin aqueous dispersion. Conventionally, vinyl acetate/vinyl chloride, diene,
Synthetic resin emulsions such as acrylic esters are used as adhesives for paper, wood, textiles, concrete, etc., and have been widely used due to their ease of handling, safety, and low cost. Alternatively, they lacked adhesive strength to metals, and particularly when adhering to such substrates, they had poor water resistance and oil resistance, and the tear strength of the adhesive surface was low. For this reason, when the purpose is to adhere to plastics or metals, thermosetting resins such as epoxy resins, phenolic resins, or urethane resins have been used as solutions in organic solvents. These are complicated and expensive to handle, and are also prone to ignition and combustion, making them extremely unsatisfactory for use. Furthermore, especially when vinyl acetate/vinyl chloride emulsion is used, its water resistance, solvent resistance, or heat resistance is insufficient. ,
When attempts were made to improve the composition by mixing water-soluble amino acid resins, there was almost no effect, and excessive thickening or coagulation was observed, making it impractical. The present invention aims to provide a synthetic resin aqueous dispersion with excellent adhesive properties, which eliminates the above-mentioned drawbacks of the conventional methods. That is, the present invention uses 2 to 50 parts by weight of a vinyl chloride-soluble urethane polymer per 100 parts by weight of the monomer mixture described below.
from an alkali metal or ammonium salt of vinyl chloride, vinyl acetate and allylsulfonic acid or methallylsulfonic acid (hereinafter collectively referred to as (meth)allylsulfonic acid) and optionally other copolymerizable monomers in the presence of parts by weight. This is a synthetic resin aqueous dispersion obtained by polymerizing a monomer mixture in an aqueous medium. The synthetic resin aqueous dispersion of the present invention exhibits extremely excellent adhesion to plastics, metals, wood, etc., does not require the addition of a curing catalyst, and can be stored for a long time as a one-component type, and can be stored at low temperatures. It exhibits strong adhesive strength through heat treatment, and also provides a coating with excellent water resistance, solvent resistance, and tear strength, and is therefore suitable for flocking or semi-adhesive painting for the purpose of preventing contamination. However, these effects are thought to be attributable to the complex synergistic effects of the monomer components and copolymer components constituting this synthetic resin dispersion. The proportion of vinyl chloride, which is the first component in the monomer mixture in the present invention, is preferably in the range of 15 to 90% by weight, and 30 to 85% by weight.
is even more preferable. If it exceeds 90% by weight, the resulting copolymer not only becomes too hard, but also tends to have low adhesive strength, while if it exceeds 15% by weight, it tends to have poor adhesion to plastics or metals. Further, the proportion of the second component, vinyl acetate monomer, in the monomer mixture is preferably in the range of 5 to 80% by weight, more preferably 15 to 65% by weight. If it exceeds 80% by weight, the solvent resistance of the resulting copolymer will decrease,
Water resistance or adhesion to metals tends to decrease, and on the other hand, if it is less than 5% by weight, the adhesiveness decreases significantly and the adhesion to various materials tends to be poor. Furthermore, the proportion of the alkali metal or ammonium salt of (meth)allylsulfonic acid, which is the third component, in the monomer mixture is preferably in the range of 0.1 to 5.0% by weight, more preferably 0.2 to 4.0% by weight. If it exceeds 5.0% by weight, the water resistance of the resulting synthetic resin aqueous dispersion tends to be poor, while if it is less than 0.1% by weight, the adhesion to various substrates tends to decrease.
Furthermore, the storage stability of the synthetic resin aqueous dispersion becomes poor and sediments are likely to be formed. Furthermore, as a desired component, a monomer copolymerizable with each of the above-mentioned monomers can be used in an amount of preferably 40% by weight or less, more preferably 20% by weight or less. As such copolymerizable monomers, for example, when imparting flexibility, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid and ethyl alcohol, butyl alcohol,
- Esters with ethylhexyl alcohol, vinyl ethers such as butyl vinyl ether, octyl vinyl ether, lauryl vinyl ether, vinyl esters of isomers of vinyl valerate, pelargonic acid, vinyl laurate, vinyl stearate, vinyl oleate, etc. Vinyl ester etc. can be used. In addition, in order to impart crosslinking properties, self-crosslinking monomers such as glycidyl methacrylate, N-methylol acrylamide, diallyl phthalate, and divinylbenzene, or crosslinking aid monomers,
Acrylic acid, methacrylic acid, itaconic acid, maleic acid, hydroxyethyl acrylate, acrylamide, etc. can be used. Furthermore, in order to adjust the compatibility with other types of polymers, for example, ethylene, propylene, methacrylonitrile, or acrylonitrile can be used in combination. The polymerization method in the present invention may be a conventionally known polymerization method in an aqueous medium, but is not particularly limited. Emulsifiers used include alkylaryl sulfonates, polyoxyethylene alkylaryl sulfates, alkali salts of succinic acid half esters, and protective colloids such as polyvinyl alcohol, alkyl cellulose, Examples include hydroxyalkylcellulose. The catalyst used is
Examples include potassium persulfate, ammonium persulfate, and hydrogen peroxide. Next, the urethane polymer soluble in the vinyl chloride monomer used in the present invention does not substantially contain hard segments, has a molecular weight of 300 or more, preferably 500 or more, and is a divalent polymer having OH groups at both ends. Although it can be obtained from alcohols and polyisocyanates having NCO groups at both ends, urethane polymers containing many urethane bonds are preferred. When a urethane polymer is dissolved in the monomer mixture and emulsion copolymerized, the urethane polymer has surfactant-like properties, and the amount of emulsifier used can be reduced, resulting in good stability. It is possible to obtain an aqueous dispersion and to perform so-called non-soap emulsion copolymerization. Moreover, physical properties such as peel strength and tear strength can be improved. The ratio of the monomer mixture to the urethane polymer is 2 to 50 parts by weight per 100 parts by weight of the monomer mixture. If the amount of the urethane polymer used is less than 2 parts by weight, the adhesive strength will be low under the adhesive condition of heating at 80°C or less, and when used as a semi-adhesive paint material, such as a strippable paint, the film will be difficult to form. The tear strength is low and unsuitable. On the other hand, if the amount of urethane polymer used exceeds 50 parts by weight, water resistance and oil resistance will be poor. However, the preferred proportion of the urethane polymer used is 3 to 40 parts by weight. The synthetic resin aqueous dispersion of the present invention has good storage stability, and when used as an adhesive, peel strength and
It has excellent physical properties such as tear strength. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. (Hereinafter, parts mean parts by weight.) In each example, parts mean parts by weight, and physical properties were evaluated by the following method. (1) Peel strength: 100-120gr/synthetic resin emulsion as a solid content in Tetoron/cotton (65/35) blended fabric.
Apply it evenly so that the area is ² m2, add vinyl chloride soft leather (thickness 3m/m) and adhere it at 70℃ x 0.5Kg/ ^cm2 x 20 minutes.
The 180° peel strength at a width of 20 m/m was measured. (2) Solvent resistance 50 to 70% solid content on smooth melamine resin plate
A synthetic resin emulsion was applied to the resin plate to give a coating weight of gr/m ² and dried at 120° C. for 2 minutes to form a film on the surface of the resin plate. Then, a urethane resin lacquer (20% by weight) using toluene as a solvent was applied uniformly to a solid content of 50 to 70g/ ^m2 , and after being left at 23°C for 2 days and nights, it was applied to a urethane resin plate. The degree of contamination was observed and evaluated. (3) Water resistance After immersing the test base material prepared for peel strength measurement in pure water at 20℃ for 2 days, the peel strength was measured, and the same strength was divided by the strength before immersion. The retention rate was determined. (4) Tear strength The same bonded base material as the test piece prepared for measuring the peel strength in (1) was scratched at a 180° angle.
The tear strength was measured. (5) Mechanical stability 1000rpm× by Maron type mechanical stability tester
Observe whether or not aggregates are formed during 5 minutes. Examples 1 to 4 and Comparative Example 1 140 parts of pure water was added to the stainless steel polymerization vessel in Table 1.
As a dispersant for 100 parts of the monomer mixture shown in
0.4 parts of PVA-217 (average degree of polymerization: 1730, degree of saponification: 88 mol%, manufactured by Kuraray Co., Ltd.) and 0.5 parts of Lebenol WZ (anionic emulsifier, manufactured by Kao Atlas Co., Ltd.),
As a catalyst, 0.10 parts of potassium persulfate and 10 parts of a urethane polymer (polymer listed in Table 1) soluble in vinyl chloride monomer were charged, and the mixture was heated at 60°C at 400 rpm for 60 minutes.
After that, polymerization was carried out for 20 hours until the internal pressure of the autoclave reached 0.5 Kg/cm ² (absolute pressure). The evaluation results of the obtained synthetic resin aqueous dispersion are also listed in Table 1. Comparative Example 2 A synthetic resin aqueous dispersion was obtained in the same manner as in Example 1 except that no polymer was used. The physical property measurement results are shown in Table 1.

【table】

[Table] What was obtained by

Claims (1)

[Claims] 1. Vinyl chloride, vinyl acetate, and an alkali metal or allylsulfonic acid or methallylsulfonic acid are added to 100 parts by weight of the monomer mixture described below in the presence of 2 to 50 parts by weight of a urethane polymer soluble in vinyl chloride. A synthetic resin aqueous dispersion obtained by polymerizing a monomer mixture consisting of an ammonium salt and optionally other copolymerizable monomers in an aqueous medium.