 Method of making a water filter |
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| Clarification tank |
| We claim: 1. An apparatus for clarifying a liquid mixture, comprising: a. a tank having means for ... |
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| Phenolic polymer prepared from o-cresol |
| What is claimed is: 1. An alkylol group containing phenolic polymer of Formula I: ##STR11## wherein:... |
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| Apparatus for increasing the pH of waste water |
| I claim: 1. Apparatus for increasing the pH of waste water, comprising a lime water having an ... |
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| Method for preparing improved expanded polystyrene sheet |
| I claim: 1. In a process for producing microcellular expanded styrene polymer sheet by extruding a ... |
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| Chemical-resistant wholly aromatic polyamide fiber material |
| OF THE INVENTION In the chemical-resistant wholly aromatic polyamide fiber material of the present ... |
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| Epoxy resin powder including ethylene vinyl acetate |
| I claim: 1. A homogeneous free-flowing powder which is shelf-stable and when heated to 185.degree.-2... |
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| Oxygen barrier laminate films including a polyalkylene carbonate adhesive |
| What is claimed is: 1. In a laminate structure comprising a base layer and a polycarbonate layer ... |
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| Device for fluidizing and distributing powder |
| What is claimed is: 1. A device for fluidizing and distributing a powder in suspension in a carrier ... |
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| Ceramic forming process |
| OF THE INVENTION INCLUSIVE OF THE PREFERRED EMBODIMENTS The invention sought to be patented ... |
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Preparation of aqueous emulsion
| Details |
Inventors: Kobayashi, Koichi; Kimura, Akihito;
Assignee: Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha (Osaka, JA)
Primary Examiner: Michl; Paul R.
Assistant Examiner:
Attorney, Agent or Firm: Armstrong, Nikaido & Wegner
Stable aqueous emulsions of acrylate polymers, methacrylate polymers or butadiene polymers, which are prepared by emulsion polymerization in the presence of hydrolyzed vinyl acetate-alkali metal olefinsulfonate copolymer as an emulsifier. The aqueous emulsions thus prepared have excellent properties in storage stability, viscosity stability, dilution stability, freeze-thaw stability and miscibility with pigment or urea resin. The emulsion can also give a film excellent in water-resistance. |
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DETAILED DESCRIPTION It has now been found that the above-mentioned objects can be attained by employing a modified PVA as an emulsifier in an emulsion polymerization, namely a hydrolyzed vinyl acetate-alkali metal olefinsulfonate copolymer having a molecular weight of 4,000 to 150,000 and of which alkali metal olefinsulfonate content is within the range of 0.
5 to 7% by mole and a degree of hydrolysis in vinyl acetate unit is at least 65% by mole.
The emulsion obtained in accordance with the present invention is superior in storage stability, miscibility with pigment or urea resin, freeze-thaw stability, viscosity stability, dilution stability and water-resistance of a film formed therefrom, to a conventional one.
Such remarkable effects are obtained only when the specific modified PVA, namely a partially or completely hydrolyzed vinyl acetate-alkali metal olefinsulfonate copolymer containing 0.
5 to 7 % by mole of alkali metal olefinsulfonate unit, is employed as an emulsifier in an emulsion polymerization instead of surface active agents.
According to the present invention, the modified PVA containing less than 0.
5 % by mole of alkali metal olefinsulfonate is substantially similar to a non-modified PVA, namely PVA per se.
On the other hand, when the alkali metal olefinsulfonate content is more than 7 % by mole, it is difficult to obtain a stable emulsion since a distribution of polymer particle size becomes broad, or water-resistance of a film formed from the emulsion drops.
In the present invention, it is essential to employ the modified PVA containing the alkali metal olefinsulfonate unit within the range of 0.
5 to 7 % by mole, preferably within the range of 1 to 3 % by mole.
Furthermore, when the modified PVA having the lower molecular weight than the before-mentioned is employed, a large quantity of macro-grains are produced or the storage stability at high temperature and freeze-thaw stability become poor and, therefore, it is difficult to obtain a practical emulsion.
On the other hand, when the modified PVA having the higher molecular weight is employed, the viscosity of the emulsion increases and then the emulsion may coagulate
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Liquid Purification 
