Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1991-12-04
1994-09-20
Reddick, Judy M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524458, 524459, 524547, 524563, 525 56, 525 61, 5253303, 5253304, 5253306, 525350, 5253305, 526201, 526202, 526204, 526214, 526220, 526223, 526224, 526319, 526344, 5263442, C08L 2904
Patent
active
053490088
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for suspension polymerization of a vinyl compound. More particularly, it pertains to a process for suspension polymerization of a vinyl compound; a suspending agent for suspension polymerization; and further, an aqueous dispersion useful as a secondary suspending agent for suspension polymerization and polyvinyl alcohol polymer.
Background Art
In industrially producing a vinyl chloride resin, there has heretofore been widely practiced a suspension polymerization process in which vinyl chloride monomer is suspended in an aqueous medium in the presence of a suspending agent and polymerized by the use of an oil-soluble catalyst. In general, the factors governing the quality of a vinyl chloride resin include conversion to polymer, water-monomer ratio, polymerization temperature, kind and amount of catalyst, type of polymerization vessel, agitation rate, kind and amount of suspending agent and the like. It is known that among them the kind of suspending agent has the most effect.
The performance required for a suspending agent for suspension polymerization of a vinyl chloride monomer include (i) the agent functions so as to exhibit a high suspending power and to make the granulometric distribution of the vinyl chloride polymer granules obtained as sharp as possible by the use of a small amount of the agent; (ii) the agent functions so as to make polymer granules obtained as uniform and porous as possible to increase the absorption rate of a plasticizer for facilitating the workability, to facilitate the removal of vinyl chloride monomer residue in polymer granules and to prevent the formation of fish eye, etc. in the molding; (iii) the agent functions so as to produce polymer granules having a high bulk density, and the like.
As a suspending agent for suspension polymerization of a vinyl compound, there has heretofore been used a cellulose derivative such as methylcellulose, carboxymethylcellulose, etc., partially hydrolyzed polyvinyl alcohol (hereinafter abbreviated as "PVA"), PVA having an ionic group at a side chain thereof or the like, alone or in combination.
However, vinyl chloride resin granules obtained by suspension polymerization of vinyl chloride by the use of a PVA or polyvinyl ester (hereinafter abbreviated as "PVES") each having an ionic group at a side chain thereof as a primary suspending agent or a secondary primary agent have favorable processing characteristics, but involve such problems as unstable suspension polymerization and the increase of scale adhered to a polymerization vessel. (Refer to Japanese Patent Application Laid-Open Nos. 137105/1980, 112985/1979 and 95103/1989)
In addition, an aqueous dispersion obtained by post-emulsification of PVA having a degree of hydrolysis of 20 to 60 mol % is very poor in stability after being allowed to stand, and is incapable of producing vinyl chloride resin granules having a satisfactory porosity and bulk density. (Refer to Japanese Patent Application Laid-Open No. 167745/1981).
Moreover, the suspension polymerization of vinyl chloride by the use of a vinyl polymer emulsion as a secondary suspending agent necessitates the preliminary agitation period of time prior to suspension polymerization by 3 to 5 times as long as an ordinary agitation period of time for the sake of attaining the effect, thus causing a serious disadvantage in workability. (Refer to Japanese Patent Application Laid-Open No. 64(1989)-51409).
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a process for suspension polymerization of a vinyl compound having favorable polymerization stability and capable of producing vinyl polymer particles with satisfactory processing characteristics.
It is another object of the present invention to provide suspending agents such as a primary suspending agent, secondary suspending agent and the like for suspension polymerization of vinyl compound to be used in the abovementioned process for suspension polymerization of a vinyl compound.
It is still anothe
REFERENCES:
patent: 3929753 (1975-12-01), Itoh et al.
patent: 4208499 (1980-06-01), Maruhashi et al.
patent: 4226966 (1980-10-01), Shiraishi et al.
patent: 4258163 (1981-03-01), Mariasl et al.
patent: 4308189 (1981-12-01), Moritani et al.
patent: 4324878 (1982-04-01), Biaggi et al.
patent: 4345056 (1982-08-01), Thyret et al.
patent: 4388442 (1983-06-01), Taniguchi et al.
patent: 4565854 (1986-01-01), Sato et al.
patent: 4592402 (1986-06-01), Shioji et al.
patent: 4797458 (1989-01-01), Sharaby
patent: 4918151 (1990-04-01), Sharaby
patent: 4931518 (1990-06-01), Sharaby
patent: 5153284 (1992-10-01), Amano
Igarashi Kazunari
Maruyama Hitoshi
Takada Shigeki
Tanaka Taku
Yuki Ken
Kuraray Co. Ltd.
Reddick Judy M.
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