JP3403526B2 - Method for producing vinyl chloride polymer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vinyl chloride polymer, and more particularly to a method for producing a high quality vinyl chloride polymer with high productivity.

[0002]

2. Description of the Related Art A vinyl chloride polymer is usually produced by suspension polymerization of a vinyl chloride monomer or a mixture of vinyl monomers mainly containing the vinyl chloride monomer with a polymerization initiator. At this time, the polymerization initiator used has a great influence on the quality characteristics such as polymerization time, productivity, scale adherence at the time of polymerization, initial colorability of the polymer, thermal stability, and odor depending on the type. give.

On the other hand, in recent years, in order to increase the productivity of vinyl chloride-based polymers, the amount of polymerization initiator added is increased,
The polymerization time has been shortened. However, an increase in the amount of the polymerization initiator added causes an influence on the polymer quality, particularly initial colorability, a decrease in thermal stability, the generation of an offensive odor, and the problem that the amount of scale attached in the polymerization vessel increases. There was also.

[0004]

Therefore, the object of the present invention is to suppress the generation of offensive odors without deteriorating the initial colorability and thermal stability of the vinyl chloride polymer, and further to prevent the scale from adhering to the scale in the polymerization vessel. An object of the present invention is to provide a method for producing a high-quality vinyl chloride polymer with high productivity with a reduced amount.

[0005]

That is, the method for producing a vinyl chloride-based polymer according to the present invention is such that (A) 3 is used as a polymerization initiator when suspension-polymerizing a vinyl-based monomer mainly containing vinyl chloride. Tertiary alkyl having a 10-hour half-life temperature of 40 to 60 ° C. in 0.1-0.2 mol / l of 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate and (B) trichloroethylene. It is characterized by being used in combination with one kind or two or more kinds of peroxyesters.

The present invention will be described in more detail below. The polymerization initiator as the component (A) used in the method of the present invention is 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate.

On the other hand, the polymerization initiator as the component (B) is
A tertiary alkylperoxy ester having a 10-hour half-life temperature of 40 to 60 ° C. in 0.1 to 0.2 mol / liter in trichloroethylene, and more specifically,

[Chemical 2] (Wherein R ¹ and R ² are each a tertiary alkyl group having 4 to 15 carbon atoms) This compound includes t-butyl peroxypivalate (0.1 mol / mol in trichloroethylene).
Temperature of 10-hour half-life in liter [the same applies below]:
58 ° C.), t-amyl peroxypivalate (54
C), t-butylperoxyneohexanoate (54
° C), t-butyl peroxy neodecanoate (49
C.), t-amyl peroxy neodecanoate (46
C), t-hexyl peroxy neodecanoate (47
C), t-octyl peroxy neohexanoate (4
9 ° C.), t-octyl peroxy neodecanoate (4
4 ° C.) and the like are used, but the invention is not limited thereto.

The mixing ratio of these components (A) and (B),
The amount used varies depending on the reaction conditions, but in general, a weight ratio of A / B is preferably 5/1 to 1/5, and if A or B exceeds this ratio, a synergistic effect cannot be expected and the initiator efficiency decreases. To do. Further, the amount of scale adhesion tends to increase.

Also, the total amount of the vinyl monomer is preferably 0.03 to 0.3% by weight, and the polymerization temperature is 35%.
A temperature of ~ 65 ° C is suitable.

Both the A and B polymerization initiators are preferably diluted with a solvent or dispersed in water to be used as an emulsion.

The vinyl chloride-based monomer used in the present invention is a mixture of vinyl chloride alone and a vinyl-based monomer copolymerizable mainly with vinyl chloride. Examples of the comonomer to be copolymerized include ethylene, methyl acrylate, vinyl acetate, acrylonitrile, and styrene, and these are used alone or in combination of two or more.

In the suspension polymerization of the present invention using these monomers, a water-soluble dispersant which is usually used in the polymerization of vinyl chloride-based monomers, such as methyl cellulose and hydroxyethyl cellulose. One kind or a combination of two or more kinds of water-soluble polymers such as celluloses and partially saponified polyvinyl alcohol may be used.

In this polymerization system, if necessary, a polymerization regulator, a chain transfer agent, a pH regulator, a gelation improving agent, an antistatic agent, a filler, which are appropriately used for vinyl chloride-based polymerization, The addition of antioxidants, scale inhibitors, etc. is also optional.

[0014]

EXAMPLES The specific contents of the present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1, Comparative Examples 1 and 2 1500 g of deionized water and 0.3 g of partially saponified polyvinyl alcohol were added as an aqueous solution to a stainless steel autoclave polymerization vessel having an internal volume of 2.2 liters. Further, after adding 200 g of a pH 7 buffer solution, the polymerization initiators of the types and amounts shown in Table 1 were added, and then the inside of the autoclave was replaced with nitrogen gas. Then, the inside of the autoclave was evacuated with a vacuum pump, and then vinyl chloride monomer 280
At the same time as the charging of g, the temperature was started to start the polymerization.

The polymerization reaction was carried out while maintaining the polymerization temperature at 57 ° C. At this time, the pressure in the polymerization kettle is 8.6 kg / cm ^2.
Met. When the pressure in the polymerization kettle dropped to 8.1 kg / cm ² , the pressure was dropped, and the polymerization was continued for 7.5 hours. After 7.5 hours, the polymerization was stopped and the unreacted monomer was recovered. The polymerization vessel was opened, the scale in the vessel was taken out, the polymer was dehydrated and dried, and subjected to the test by the following method. The results are also shown in Table 1.

The scale adherence inside the polymerization vessel was evaluated according to the following criteria. ◯: The amount of scale attached is 0.6 g or less. Δ: The amount of scale attached is 0.6 to 1.0 g. X: The adhered amount of scale is 1.0 g or more.

Initial colorability: 100 parts by weight of the obtained polymer was mixed with 2.5 parts by weight of dibutyl tin malate and 80 parts by weight of dioctyl phthalate, kneaded with a roll at 160 ° C. for 10 minutes, and taken out as a 1 mm sheet. The color condition was visually observed.

Odor: During the above-mentioned initial colorability test, the presence or absence of an offensive odor was investigated. Existence: A foul odor is generated. None: No offensive odor is generated.

The abbreviations for the polymerization initiators in the table are as follows:
Each means the following. # 610: 3-hydroxy-1,1-dimethylbutyl peroxy neodecanoate (36 ° C.) # 10: t-butyl peroxy neodecanoate (49
In addition, the amount of the initiator added means a conversion to a monomer based on a pure product.

[0020]

[Table 1] ──────────────────────────────────── Example 1 Comparative Example 1 Comparative Example 2 ─────────────────────────────────── Polymerization initiator # 610 / 0.0215% # 10 / 0.0364% # 610 / 0.043% Type and amount # 10 / 0.0182% ──────────────────────────────────── Pressure Fall time 370 450 420 (min) ───────────────────────────────────── 6. At the end of polymerization 2 7.9 7.5 Pressure in kettle (kg / cm ² ) ─────────────────────────────────── ── Scale adhesion ○ △ ○ Status ──────────────────────────────────── Odor ────────────────────────────────── Good initial colorability Good almost good ───────── ────────────────────────────

Example 2 and Comparative Examples 3 to 5 1500 g of deionized water and 0.3 g of partially saponified polyvinyl alcohol were added as an aqueous solution to a stainless steel autoclave polymerization vessel having an internal volume of 2.2 liters. Further, after adding 200 g of a pH 7 buffer solution, the polymerization initiators of the types and amounts shown in Table 2 were added, and then the inside of the autoclave was replaced with nitrogen gas. Then, the inside of the autoclave was evacuated with a vacuum pump, and then vinyl chloride monomer 280
At the same time as the charging of g, the temperature was started to start the polymerization.

The polymerization reaction was carried out while maintaining the polymerization temperature at 53 ° C. At this time, the pressure in the polymerization kettle is 7.7 kg / cm ^2.
Met. When the pressure in the polymerization kettle dropped to 7.2 kg / cm ² , the pressure was dropped, and the polymerization was continued for 7.5 hours. After 7.5 hours, the polymerization was stopped and the unreacted monomer was recovered. The polymerization vessel was opened, the scale in the vessel was taken out, the polymer was dehydrated and dried, and the subsequent tests were conducted. The results are also shown in Table 2.

The abbreviations for the polymerization initiators in the table are as follows:
Each means the following. # 610: 3-hydroxy-1,1-dimethylbutyl peroxy neodecanoate (36 ° C.) # 10: t-butyl peroxy neodecanoate (49
C.) # 188: α-cumylperoxy neodecanoate (3
8 ° C.) Further, the amount of the initiator added means a pure product conversion with respect to the monomer.

[0024]

[Table 2] ──────────────────────────────────── Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 ──────────────────────────────────── # 610 / 0.020% # 188 / of the polymerization initiator 0.021% # 610 / 0.040% # 10 / 0.034% Type and amount of addition # 10 / 0.017% # 10 / 0.017% ────────────────────────── ──────────── Pressure drop time 420 Not happening Not happening Not happening (min) ────────────────────────── ─────────── 7.0 7.3 7.4 7.4 7.6 Pressure in the kettle (kg / cm ² ) ────────────── ────────────────────── Scale adhesion ○ ○ ○ △ Status ────────────────────── ── ──────────── Odorless No Yes No No ───────────────────────────────── ──── Good initial colorability Good almost good ─────────────────────────────────────

Examples 3 and 4 and Comparative Examples 6 and 7 1500 g of deionized water and 0.3 g of partially saponified polyvinyl alcohol were added as an aqueous solution to a stainless steel autoclave polymerization vessel having an internal volume of 2.2 liters. . Further, after adding 200 g of a pH 7 buffer solution, the polymerization initiators of the types and amounts shown in Table 3 were added, and then the inside of the autoclave was replaced with nitrogen gas. Then, the inside of the autoclave was evacuated with a vacuum pump, and then vinyl chloride monomer 280
At the same time as the charging of g, the temperature was started to start the polymerization.

The polymerization reaction was carried out while maintaining the polymerization temperature at 45 ° C. At this time, the pressure in the polymerization kettle is 6.1 kg / cm ²
Met. When the pressure in the polymerization kettle dropped to 5.6 kg / cm ² , the pressure was dropped, and the polymerization was continued for 7.5 hours. After 7.5 hours, the polymerization was stopped and the unreacted monomer was recovered. The polymerization vessel was opened, the scale in the vessel was taken out, the polymer was dehydrated and dried, and then subjected to the subsequent tests. The results are also shown in Table 3.

The abbreviations for the polymerization initiators in the table are as follows:
Each means the following. # 610: 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate (36 ° C.) # 546: t-amylperoxy neodecanoate (4
6 ° C.) # 844: t-octylpaoxy neodecanoate (4
4 ° C.) # 188: α-cumylperoxy neodecanoate (3
8 ° C.) Further, the amount of the initiator added means a pure product conversion with respect to the monomer.

[0028]

[Table 3] ──────────────────────────────────── Example 3 Example 4 Comparative Example 6 Comparative Example Example 7 ──────────────────────────────────── Polymerization initiator # 610 / 0.036% # 610 / 0.036% # 188 / 0.0378% # 610 / 0.072% Type and amount # 546 / 0.032% # 844 / 0.037% # 844 / 0.037% ──────────────────── ───────────────── Pressure drop time 390 380 400 400 410 (min) ─────────────────────── ───────────── 4.9 At the end of polymerization 4.75 5.1 5.25 Pressure inside the kettle (kg / cm ² ) ──────────── ──────────────────────── Scale adhesion ○ ○ ○ ○ Status ─────────────────── ──────────────── Odorless No No Yes No ───────────────────────────── ──────── Initial colorability Good Good Almost good Good ─────────────────────────────────── ──

[0029]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to suppress the generation of offensive odors and further reduce the amount of scale adhered in the polymerization vessel without deteriorating the initial colorability and heat stability of the vinyl chloride polymer. Therefore, a high-quality vinyl chloride polymer can be produced with high productivity, and the industrial effect is extremely large.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-3-20309 (JP, A) JP-A-4-198306 (JP, A) JP-A-5-105709 (JP, A) JP-A-59- 216870 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 4/00-4/82 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. When (A) 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate and (B) are used as polymerization initiators when suspension-polymerizing a vinyl-based monomer mainly containing vinyl chloride. ) 0.1-0.2 in trichlorethylene
Temperature of 10-hour half-life in mol / liter is 40 to
1 of the tertiary alkyl peroxyesters at 60 ° C
A method for producing a vinyl chloride-based polymer, which is used in combination with one kind or two or more kinds. 2. 0.1 to 0.2 in trichlorethylene
Temperature of 10-hour half-life in mol / liter is 40 to
The tertiary alkyl peroxyesters having a temperature of 60 ° C. are represented by the general formula: The method according to claim 1, wherein the compound is represented by (wherein R ¹ and R ² are each a tertiary alkyl group having 4 to 15 carbon atoms). 3. 0.1 to 0.2 in trichlorethylene
Temperature of 10-hour half-life in mol / liter is 40 to
The tertiary alkyl peroxyesters at 60 ° C are t
-Butyl-peroxypivalate, t-amylperoxypivalate, t-butylperoxyneohexanoate, t-butylperoxyneodecanoate, t-amylperoxyneodecanoate, t-hexylper The method according to claim 1 or 2, which is a compound selected from one or more of oxyneodecanoate, t-octylperoxyneohexanoate and t-octylperoxyneodecanoate.