JPS5968302A - Dispersion stabilizer for suspension polymerization of vinyl compound - Google Patents

Abstract

PURPOSE:To dispersion stabilizer which, when used in the suspension polymerization of a vinyl compound, can provide a product having a particle diameter of a range favorable for processing, comprising partially saponified PVA containing specified amounts of both hydrophobic and carbonyl groups on its side chains. CONSTITUTION:A dispersion stabilizer for the suspension polymerization of a vinyl compond, comprising modified PVA containing both hydrophobic and carbonyl groups and containing 0.01-5mol% hydrophobic groups on its side chains and an absorbance at a wavelength of 280mmu of at least 0.15 when determined in a 0.1% aqueous solution, and a degree of saponification degree of 60-90mol%. When this stabilizer is used in the suspension polymerization of a vinyl compound, the dispersion of the monomer and its stabilization can be effected by using the stabilizer in an amount which is smaller than usual, and the produced polymer has a sharp particle size distribution, a large porosity, good plasticizer absorption, and a low residual monomer content and can provide a molding of very few fish eyes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dispersion stabilizer for suspension polymerization of vinyl compounds, particularly to a dispersion stabilizer for suspension polymerization preferably used in suspension polymerization of vinyl chloride.

Conventionally, for example, when producing vinyl chloride polymer (hereinafter abbreviated as PVC) by suspending and polymerizing vinyl chloride monomer in water, it is necessary to disperse the monomer oil droplets well in water and prevent the generated PVC particles from being located. Dispersion stabilizers for suspension polymerization are used in Such dispersion stabilizers include polyvinyl alcohol/I/ (hereinafter abbreviated as PVA), cellulone derivatives, and surfactants, among which P.
VA, especially partially saponified Pl/A, is often used because it has excellent dispersing power.

Recently, PvC has been used to improve productivity in resin processing, allowing stable operation with high efficiency and saving labor.

High-quality P that contributes to cost reduction through automation
vC is strongly requested. That is, the PVC particle size is within a specific range that is convenient for processing.

Its particle size distribution is sharp, with a suitable +q porosity (
There is a demand for the production of PvC powder that has the following properties: porosity), good plasticizer absorption, low residual monomer content, and no fish eyes when molded into molded products such as plastic sheets. There is.

However, conventional partially saponified P'VA is no longer able to fully satisfy these requirements. , - as a modified PvA to satisfy these requirements, e.g.

(1) Carbonyl group-containing partially saponified PTA
7-29482) Partially saponified PVA having a hydrophobic group at the (n) terminal (JP-A-18779) Proposed.

However, Pvc obtained using these PTAs does not satisfy all of the above-mentioned required characteristics.

The present inventors have conducted intensive research with the aim of providing a dispersion stabilizer for suspension polymerization that can produce 1U of vinyl polymer that satisfies the required performance as described above. The present invention was achieved based on the discovery that a partially saponified PVA having a hydrophobic group and a carbonyl group of a specific color achieves this object.

That is, in the present invention, the side chain contains 0.01 to 5 mol% of hydrophobic groups.
It has an absorbance of 0.1% water rII solution at a wavelength of 280 mμ of 0o15 or more, and a degree of saponification of 60 to 9.
This is a dispersion stabilizer for suspending vinyl compounds consisting of 0 mol% of modified PTA.

The present invention will be explained in more detail below.

The modified PVA constituting the dispersion stabilizer of the present invention is characterized by having both a hydrophobic group and a carbonyl group.

Each has effects that cannot be obtained by modification alone.

In the dispersion stabilizer of the present invention, the content of hydrophobic groups in the modified PTA is 0.01 to 5 mol%, preferably 1 to 2 mol%.
The content π of the carbonyl group has an absorbance of 0.151R1 at a wavelength of 280 mμ of a 0.1% aqueous solution.

Preferably it is 0°20 to 1°O. Outside these ranges, the purpose of the invention cannot be achieved. The degree of saponification of the modified PVA is preferably 60 to 90 mol%/L7L, preferably 70 to 80 mol%. If the degree of saponification is within the entire range specified in 11 above, the obtained PvC powder has good results in terms of particle size, FSt degree fractional distribution rosity, and fish eyes in molded products made from such PvC. Not obtained.As modified PVA, the degree of polymerization is 200 to 2600.
500 to 1500 can be preferably used, especially 500 to 1500
Preferably.

The method for producing modified Pv is not particularly limited, and for example, a suitable combination of (1) a method of introducing a hydrophobic group into a side chain and (2) a method of introducing a carbonyl group' group can be employed.

(]) As a method for introducing a hydrophobic group into the side button, for example, (a vinyl compound having an N hydrophobic group, such as an alkyl vinyl ether, α-melefin.

A method of copolymerizing and saponifying aliphatic vinyl ester, etc. and vinyl acetate fB] A method of acetalizing MA with an aliphatic monoalde (2) A method of introducing a carbonyl group, for example, using aldehydes or ketones Vinyl acetate V in the presence of
Examples include bulk polymerization or solution polymerization.

When vinyl compounds are subjected to suspension polymerization using the dispersion stabilizer of the present invention, 1 dispersion can be stabilized with a smaller amount than usual, and the resulting polymer has a sharp particle size distribution, large porosity, and good plasticizer absorption. In addition, the amount of residual monomer in the polymer is small, and molded products with extremely few fish eyes can be obtained from such a polymer.

As explained above, the dispersion stabilizer of the present invention is a combined dispersion stabilizer made of modified PVA containing a hydrophobic group and a carbonyl group. The following polymerization conditions are preferably employed for suspension polymerization of the vinyl thread yarn.

For example, when manufacturing PVC, add 0.01% to 0.3% of stabilizer to vinyl chloride.
It is particularly preferable to add 0.02 to 0.1% by weight.

Also.

The ratio of vinyl chloride and water is 1:1 to 1:1 by weight.
1:3. In particular, the ratio is preferably 1:1 to 1:2.

The type of polymerization initiator used is not particularly limited, but organic peroxides, peresters, dialkyl carbonates, azo compounds, etc. are preferably used. Also,
These M-initiators can be used alone or in combination. Also.

To adjust the degree of polymerization of PvC, chain transfer agents such as saturated hydrogen such as pentane, carbon tetrachloride, saturated hydrogen hypohydride such as trichloroethylene, thioglycolic acid ester, mercapto alcohol, etc. are used. You can stop. The polymerization temperature is preferably about 50 to 75°C, particularly about 50 to 70°C.<9 The polymerization time is preferably from 5 to 17 hours, particularly preferably from 7 to 15 hours.

The stabilizer can also be used in combination with other stabilizers such as PTA, cellulose derivatives, surfactants, etc.

Hereinafter, the explanation has focused on examples of polymerization of vinyl chloride.

The use of the dispersion stabilizer of the present invention is not limited to the polymerization of vinyl chloride, but can also be used for copolymerization of vinyl chloride and other vinyl compounds, and for the polymerization of various vinyl compounds such as nutylene and methyl methacrylate. .

EXAMPLES The present invention will be described in more detail below with reference to Examples.

Example 1 ((Trans)Production of dispersion stabilizer (1) Vinyl acetate A/11 [10 parts (parts by weight, same hereinafter).

).

(2) 1156 parts of Nukuno, (3) 12 parts of lauryl vinyl ether, and (4) 15 parts of acetaldehyde were charged into a polymerization reactor and polymerized in a conventional manner at t, after which unreacted vinyl acetate and acetaldehyde were expelled.

Next, the obtained Ichi6 body solution was saponified with sodium hydroxide in a conventional manner to obtain modified PVA. The obtained modified PV'A had a furyl ether group content of 0.3 mo/l/%.

The absorbance of 0.1% water fg liquid at wavelength 280+Jz is 0.24, and the degree of double polymerization is 800. The degree of saponification was 72.5 mol%.

(b) Suspension polymerization of vinyl chloride In a 1001 capacity Nubunless autoclave equipped with a stirrer, 10 parts of vinyl chloride monomer, 200 parts of water,
The ratio of 0.2 part of the above dispersion stabilizer and 0.2 part of lauroyl peroxide as a polymerization catalyst was charged at ε and the rotational speed was 40 O.
Suspension JJT was carried out by controlling the temperature in the range of 30 to 70° C. while stirring at r, p, m. Table 1 shows the performance of the obtained PvC powder.

Example 2 (Production of at dispersion stabilizer) (1) 1100 parts of vinyl acetate, (2) 55 parts of methanol.

(3) Persatic acid vinyl 1V (V engineering*chemistry 1ff,
24 parts of rHeoZ<10J) and 17 parts of (4) propionaldehyde were placed in a polymerization reactor and polymerized by a conventional method. Unreacted vinyl acetate and propionaldehyde were then expelled.Then, the resulting polymer solution was mixed with diluted soda. Saponification was performed to obtain denatured PvA. The obtained modified PVA has 1.1 mol% of persatic acid ester groups, and the absorbance of a 0.1% aqueous solution at a wavelength of 280 mIj is 0.25, which is 1.
The weight was 840° and the degree of saponification was 70.8 mol%.

(Suspension polymerization of vinyl chloride Example 1 except that the above modified PVA was used as a dispersant)
Suspension polymerization was carried out in the same manner as above. Table 1 shows the performance of the obtained PvC powder.

Example 6 fa) Preparation of dispersion stabilizer Beak (1) Vinyl acetate Y1.20c 1 part, (2) Stearyl vinyl ether N8 parts and +3) Propionaldehyde 28
A portion of the polymer was placed in a polymerization vessel and subjected to bulk polymerization using a conventional method. Unreacted vinyl acetate and propionaldehyde were then expelled using a conventional method.9Then, the resulting polymer solution was saponified with hydrocarbon soda to obtain modified PTA. The obtained modified PVA had 0.4 mol% of nutaryl ether groups and 0.1% water rf
g'D (7) The absorbance at wave Vq 280 mIi is 0.30 and $α degree 790. The degree of saponification was 71.5 mol%.

(b) Suspension polymerization of FM vinyl Suspension polymerization was carried out in the same manner as in Example 1 except that the above modified Pv8 was used as a dispersant. Table 1 shows the performance of the obtained PvC powder.

Comparative Example 1 Polymerization and saponification reactions were carried out in the same manner as in Example 1, except that only vinyl acetate A/NOO and 700 parts of methanol were used, and the use of acetaldehyde and lauryl vinyl ether was omitted, resulting in a saponification degree of 72.0 mol. %9 Degree of polymerization 780
, PVA having an absorbance of 0.01 at 28 OFFl/i of a 0.1% aqueous solution was obtained. Suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that 20 PvA was used as a dispersion stabilizer. Table 1 shows the performance of the obtained PvC powder.
Comparative Example 2 Polymerization and saponification reactions were carried out in the same manner as in Example 1 except that only 1100 parts of vinyl acetate, 56 parts of methano-Iv and 15 parts of acetaldehyde were used and the use of lauryl vinyl ether was omitted. A PVA with a polymerization degree of 73, j mol %, a polymerization degree of 840, and an IW luminous intensity of 0.23 in [2130 m7 of a 1.1% aqueous solution] was obtained. This PVA
Suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that 2 was used as a dispersion stabilizer. The amount of PvC powder obtained is also listed in Table 1.

Comparative Example 3 Vinyl acetate 110flP+L vinyl parzadeicate 24
Polymerization and saponification reactions were carried out in the same manner as in Example 2, except that 700 parts of acetate and 700 parts of methanol were used, and the use of acetate 7/I/dehyde was omitted.
Absorbance at 280 mμ of 1.1 mol%, 0.1% aqueous solution is 0.01, degree of saponification is 72.5 mol%, degree of polymerization is 7.
900 PvA was obtained. Suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that this PVA was used as a dispersant. The performance of the obtained PVC powder is also listed in Table 1.

PVC thing 1 <-= measurement method (1) Bulk specific gravity: According to JIS K 6721.

(2) Viscosity distribution: Based on TIS Z8RO1.

(3) Porosity - Pore radius 75-7500 [] by HCARLO FRBA mercury pressure porosimeter
A was measured.

(4) Plasticizer absorption: PVC400f and dioctyl phthalate 200G' were put into a distillation mixer.

The time it takes for diocdyl phthalate to be absorbed by PvC while rotating at an internal temperature of 85°C.

(5) Fisheye: PVC100Q, 40g of dioctyl phthalate, 1g of barium stearate,
Lead stearate19. Fa, acid lead 1q and ultramarine blue 15
f and kneaded with a 150C mixing roll.

6 minutes, 5 minutes, and 7 minutes after the start of kneading, the thickness is 0.25, respectively.
A tll sheet was prepared, and the number of ungelled particles within 100 d was counted.

Patent applicant Unitika Chemical Co., Ltd. Agent Kodama
Yuzo

Claims (1)

[Claims] (1) It has a hydrophobic group on the side f1°1 (1, old ~ 5 mo A dispersion stabilizer for VQ dry polymerization of vinyl compounds consisting of 90% modified polyvinyl alcohol.