JP3484741B2 - Polymerization method of vinyl chloride - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith (hereinafter abbreviated as vinyl chloride monomer). By using a specific polymerization initiator, it is possible to obtain polyvinyl chloride which has no physical odor and has good physical properties such as initial colorability, heat stability, fish eye, and plasticizer absorbability with good productivity. It relates to a polymerization method.

[0002]

2. Description of the Related Art Polyvinyl chloride is a thermoplastic resin having excellent physical properties and is used as a hard and soft material in many fields. In recent years, polyvinyl chloride manufacturers have been trying to shorten the polymerization time for the purpose of improving productivity. To shorten the polymerization time, it is necessary to increase the polymerization rate to the limit of the heat removal capacity of the polymerization vessel throughout the polymerization, so-called high-speed polymerization, and therefore, use a large amount of polymerization initiator, or A method of using a polymerization initiator having higher activity has been adopted. However, when a large amount of a polymerization initiator is used, the initial coloring property and heat stability of the obtained polyvinyl chloride are deteriorated and the commercial value is reduced, so that there is a limit to the reduction of the polymerization time by this method. On the other hand, it is known that the method using a high activity polymerization initiator can shorten the polymerization time relatively easily, and there has been a strong demand for a high activity polymerization initiator from the past, and several polymerization initiators have been developed so far. Has been done.

As such conventional high activity polymerization initiators, for example, acetylcyclohexyl sulfonyl peroxide (hereinafter abbreviated as ACSP), diisobutyryl peroxide (hereinafter abbreviated as IBPO) (Japanese Patent Laid-Open Publication No. 5 (1999) -52945).
4-11190), cumyl peroxyneodecanoate (hereinafter abbreviated as CND) (JP-A-58-12).
No. 0611), t-octyl peroxy neodecanoate (hereinafter abbreviated as OND) (JP-A-58-12).
No. 0613) is known.

However, each of these conventional high activity polymerization initiators also has the following problems. That is, ACSP has poor physical properties such as heat stability, fish eye and plasticizer absorption of the obtained polyvinyl chloride, and ISP
BPO has a problem that since the polymerization activity is not sustained, the productivity is lowered as a result, and the resulting polymer has an initial coloring property. CND has the disadvantage that it has the characteristic odor of polymers due to degradation products. Further, since it has a benzene ring in the structure, a UV absorption peak appears in the extraction test of the obtained polyvinyl chloride, so that there is a problem that its application in the medical and food fields is limited. OND gives polyvinyl chloride with relatively good physical properties, but ACSP and IBP
Since it is inferior in activity to O and CND, it is still unsatisfactory in practical use.

[0005]

With the progress of equipment technology, recently, the heat removal capacity of the polymerization reactor has been remarkably improved.
It has become possible to improve the polymerization rate more than ever, and there is an increasing demand for a polymerization initiator having a higher activity than conventional products and capable of obtaining polyvinyl chloride having good physical properties.

The object of the present invention is to meet the above-mentioned needs, and by using a novel polymerization initiator, there is no odor, and initial coloring property, heat stability, fish eye, plasticizer absorbability, etc. An object of the present invention is to provide an improved method for polymerizing vinyl chloride, which enables to obtain polyvinyl chloride having good physical properties with high productivity.

[0007]

DISCLOSURE OF THE INVENTION As a result of long-term research, the present inventors have confirmed that all the problems of conventional initiators can be solved by using the following polymerization initiators. Was completed.

That is, the present invention uses the (A) general formula as a polymerization initiator when polymerizing a vinyl chloride-based monomer.

[Chemical formula 3] Di-t-alkylperoxydiglycolate represented by
Of these, di-t-butylperoxydiglycolate, di-
t-hexyl peroxydiglycolate, bis (1,
1,2-Trimethylpropylperoxy) diglycole
G, bis (1,1,3,3-tetramethylbutylpero
Xy) diglycolate, bis (1-cyclohexyl-1)
-Methylethylperoxy) diglycolate, bis (ii)
Sopropylcumylperoxy) diglycolate is used alone, or (A) and (B) the 10-hour half-life temperature in benzene at 0.1 mol / L is 33-6.
A method for polymerizing vinyl chloride, characterized in that a polymerization initiator having a temperature of 0 ° C. is used in combination.

The vinyl chloride monomer used in the present invention is
A vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith.

Other monomers copolymerizable with the vinyl chloride monomer used in the present invention are, for example, ethylene, vinyl acetate, vinylidene chloride, styrene, acrylic acid ester and the like.

Used as a polymerization initiator in the present invention
Di-t-alkylperoxy represented by the general formula (Formula 1)
Diglycolate is specifically di-t-butylperoxide.
Xydiglycolate, di-t-hexyl peroxydig
Lycolate, bis (1,1,2-trimethylpropyl ether
Luoxy) diglycolate, bis (1,1,3,3-thero)
Tramethylbutylperoxy) diglycolate, bis
(1-cyclohexyl-1-methylethylperoxy)
Diglycolate, bis (isopropyl cumyl peroxy
D) Any of diglycolate.

The di-t-alkylperoxydiglycolate is synthesized according to a conventional method for producing a peroxyester. That is, it can be obtained by reacting a diglycolic acid halide with a corresponding hydroperoxide in the presence of an alkaline compound or a tertiary amine.
The reaction temperature at that time is usually -10 to 30 ° C.

The 10-hour half-life temperature at 0.1 mol / L in benzene used together with the above-mentioned di-t-alkylperoxydiglycolate in the present invention is 33-6.
Specific examples of the polymerization initiator having a temperature of 0 ° C. include, for example, peroxyesters, t-butylperoxy neodecanoate (47 ° C.), t-hexylperoxy neodecanoate (45 ° C.), 1,1,2. -Trimethylpropylperoxy neodecanoate (41 ° C), 1-cyclohexyl-1-methylethylperoxyneodecanoate (41 ° C), t-octylperoxyneodecanoate (41 ° C), cumylperoxyneodecanoate Ate (37
C), α, α′-bis (neodecanoylperoxy) diisopropylbenzene (36 ° C.), t-butylperoxypivalate (55 ° C.), t-hexylperoxypivalate (53 ° C.) and the like. Further, examples of the dialkyl peroxydicarbonate include bis (2-ethylhexyl) peroxydicarbonate (43 ° C.) and diisopropyl peroxydicarbonate (41 ° C.), and examples of the diacyl peroxide include IBPO.
(33 ° C.), 3,5,5-trimethylhexanoyl peroxide (60 ° C.) and the like.

One or more of these polymerization initiators are appropriately selected depending on the polymerization conditions such as the polymerization temperature and the polymerization time, and the intended use of the obtained polyvinyl chloride. -Used in combination with alkylperoxydiglycolate.

When the combination of the polymerization initiators (A) and (B) is used in combination, the mixing ratio and the amount of the polymerization initiators may be appropriately determined according to the reaction conditions. Usually, the mixing ratio is the polymerization initiator ( A): Polymerization initiator (B) = 100: 0 to 5: 9
5 parts by weight.

The amount of the polymerization initiator used in the present invention can be appropriately selected, but usually the amount of the vinyl chloride monomer charged is 1
The amount is about 0.001 to 2 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight as a pure product. If the amount is less than 0.001 part by weight, the polymerization rate will be slow. On the other hand, if the amount exceeds 2 parts by weight, it becomes difficult to control the polymerization reaction and the physical properties of the obtained polymer are deteriorated, which is not preferable.

The polymerization method used in the present invention may be ordinary suspension polymerization or emulsion polymerization, and the polymerization temperature is generally 20 to 70 ° C, preferably 30 to 60 ° C. If the polymerization temperature is lower than 20 ° C, the polymerization time tends to be long, and if it exceeds 70 ° C, the life of the polymerization initiator is shortened, which is disadvantageous.

[0018]

The present invention using a specific polymerization initiator has the following features. That is, as compared with the conventional method using a polymerization initiator, a polyvinyl chloride polymer having good physical properties such as initial colorability, heat stability, fish eye, and plasticizer absorbability can be obtained with high productivity. Moreover, since the obtained polymer does not have an odor due to a decomposed product of peroxide, it is preferable from the viewpoint of the work cycle when a soft product is produced by adding a plasticizer to the polymer and kneading. In addition, the highly active polymerization initiator used in the present invention exhibits sufficient activity even in low temperature polymerization (polymerization temperature of 50 ° C. or lower) carried out in order to obtain polyvinyl chloride having a high degree of polymerization. Can significantly improve the productivity in the production of high degree of polymerization.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. The abbreviations of the polymerization initiators used in Examples and Comparative Examples, their chemical names, and their 10-hour half-life temperatures at 0.1 mol / L in benzene are shown.

(Di-t-alkylperoxydiglycolate) BDG: Di-t-butylperoxydiglycolate (35 ° C.) HDG: Di-t-hexylperoxydiglycolate (32 ° C.) TPDG: Bis (1, 1,2-Trimethylpropylperoxy) diglycolate (26 ° C) CyDG: Bis (1-cyclohexyl-1-methylethylperoxy) diglycolate (26 ° C) ODG: Bis (1,1,3,3-tetramethylbutylperoxy) diglycolate (25 ° C.) PCDG: Bis (isopropylcumylperoxy) diglycolate (21 ° C.) (Polymerization initiator represented by (B) coexisting with di-t-alkylperoxydiglycolate) BND: t-butylperoxy neodecano Eat (4
7 ° C.) HND: t-hexyl peroxyneodecanoate (45 ° C.) OPP: bis (2-ethylhexyl) peroxydicarbonate (43 ° C.) IBPO: diisobutyryl peroxide (33 ° C.) (polymerization used in Comparative Examples Initiator) ACSP: Acetylcyclohexylsulfonyl peroxide (27 ° C.) IBPO: Diisobutyryl peroxide (33 ° C.) CND: Cumyl peroxyneodecanoate (37
℃) OND: t-octyl peroxyneodecanoate (41 ℃)

Example 1 150 ml of ion-exchanged water and 0.1 g of polyvinyl alcohol were placed and dissolved in a stainless steel autoclave having a volume of 400 ml. Next, 0.04g BD calculated as pure product
G was added, cooled to -80 ° C or lower, and 100 g of vinyl chloride monomer was added. The space in the autoclave was sufficiently replaced with nitrogen gas, and the container was sealed. It was immersed in a constant temperature water bath kept at 50 ° C. for 5 hours for polymerization. For stirring, the autoclave was placed in a water tank at 32 r. p. m. It was carried out by rotating with. After the polymerization, the reaction mixture was cooled, the unreacted vinyl chloride monomer was removed, the obtained white powder was washed twice with 100 ml of water, and then dried under vacuum. Experiments under the same conditions were conducted in parallel using three autoclaves, and the polymerization conversion rate was obtained from the average value of dry weight obtained in each experiment.
As a result, the conversion rate was 82% and the average degree of polymerization was 149.
It was 0.

The physical properties of the obtained vinyl chloride polymer were tested on the following items. Table 1 for each result
Shown in. [Initial Coloring Property] 100 parts by weight of a vinyl chloride polymer, 2.5 parts by weight of dibutyl tin malate, and 80 parts by weight of dioctyl phthalate as a plasticizer are mixed and kneaded on a roll at 160 ° C. for 10 minutes to form a sheet having a thickness of 1 mm. I took it out.
From the degree of coloration of the sheet visually, it was shown as follows. ○: Not colored △: Slightly colored yellow ×: Clearly colored yellow [Thermal stability test] 50 parts by weight of vinyl chloride polymer, 20 parts by weight of dioctyl phthalate, 1 part of Ba—Zn stabilizer,
1 part of the epoxy stabilizer was mixed and kneaded on a roll at 160 ° C. for 5 minutes, and a 0.5 mm thick sheet was taken out.
The formed sheet was heated in a gear oven at 190 ° C., and the coloring of the sheet was observed with time. ◯ ... Blackening time 100 minutes or more Δ ... 〃 80 to 100 minutes ×… 〃 80 minutes or less [Odor] In the above initial colorability test and thermal stability test, the odor of the sheet when the sheet was taken out from the roll was examined. According to the strength of the odor, the following is shown. O: No odor or very faint odor Δ: Weak odor X: Strong odor [Fish eye] 25 parts by weight of dioctyl phthalate and 2 parts by weight of stabilizer were added to 50 parts by weight of vinyl chloride polymer, mixed, and then mixed at 140 ° C. The number of fish eyes recognized in 100 cm ^{2 of a} 0.3 mm-thick sheet obtained by kneading each for 5 minutes with a roll was shown. [Plasticizer absorbency] 20 parts by weight of dioctyl phthalate was added as a plasticizer to 10 parts by weight of a vinyl chloride polymer, and after left for 1 hour, the unabsorbed plasticizer was separated and removed by a centrifuge and absorbed by the polymer. It is shown in% by weight of plasticizer.

Examples 2 to 11 Using the polymerization initiators shown in Table 1, vinyl chloride monomers were polymerized according to Example 1 at the polymerization temperatures shown in Table 1. The results are shown in Table 1, respectively.

Example 12 The vinyl chloride monomer was changed to 90 parts by weight of vinyl chloride monomer and 10 parts by weight of vinyl acetate monomer, and the addition amount of BDG was adjusted to 0.
The monomers were polymerized in the same manner as in Example 1 except that the amount was changed to 025 g. The results are shown in Table 1, respectively.

Comparative Examples 1 to 6 As polymerization initiators, ACSP, IBPO, CND, ON
Polymerization of vinyl chloride monomer was carried out according to Example 1 under the conditions shown in Table 1 except that D was used alone. The results are shown in Table 1, respectively.

Comparative Examples 7 and 8 Example 1 under the conditions shown in Table 1 except that IBPO or CND and OPP were used in combination as the polymerization initiator.
Polymerization of vinyl chloride monomer was carried out according to The results are shown in Table 1, respectively.

[0027]

[Table 1]

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-3-20309 (JP, A) JP-A-62-81366 (JP, A) JP-A-63-289007 (JP, A) JP-A-63- 289006 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 4/00-4/82 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. When polymerizing a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith,
General formula [Chemical formula 1] Di-t-alkylperoxydiglycolate represented by
Of these, di-t-butylperoxydiglycolate, di-
t-hexyl peroxydiglycolate, bis (1,
1,2-Trimethylpropylperoxy) diglycole
G, bis (1,1,3,3-tetramethylbutylpero
Xy) diglycolate, bis (1-cyclohexyl-1)
-Methylethylperoxy) diglycolate, bis (ii)
A method for polymerizing vinyl chloride, characterized in that any one of sopropylcumylperoxy) diglycolate is used as a polymerization initiator. 2. When a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith are polymerized, a compound represented by the general formula (A): Di-t-alkylperoxydiglycolate represented by
Of these, di-t-butylperoxydiglycolate, di-
t-hexyl peroxydiglycolate, bis (1,
1,2-Trimethylpropylperoxy) diglycole
G, bis (1,1,3,3-tetramethylbutylpero
Xy) diglycolate, bis (1-cyclohexyl-1)
-Methylethylperoxy) diglycolate, bis (ii)
Any one of sopropylcumylperoxy) diglycolate and (B) a polymerization initiator having a 10-hour half-life temperature of 33 to 60 ° C. at 0.1 mol / L in benzene. Method of polymerizing vinyl.