JPH07258317A - Method for polymerizing vinyl chloride - Google Patents

Abstract

PURPOSE:To manufacture polyvinyl chloride, with a high productivity, free from odor and having good properties in respect of initial coloring, heat stability, fish eye, plasticizer absorption, etc. CONSTITUTION:In the polymerization of a vinyl chloride monomer, 1- methylcyclohexyl peroxyneoalkanoate of the formula, wherein R1, R2, and R3 each represent a straight-chain or branched alkyl group having 1 to 9 carbon atoms, provided that the total number of carbon atoms in R1, R2, and R3 is 3 to 11, is used as a polymerization initiator either alone or in combination with another polymerization initiator having a 10-hr half-life temp. of 33 to 65 deg.C as measured in a concentration of 0.1mol/liter in benzene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has less odor than vinyl chloride monomer or vinyl chloride monomer and monomer copolymerizable therewith (hereinafter abbreviated as vinyl chloride monomer). The present invention also relates to a method for polymerizing vinyl chloride, which enables to obtain polyvinyl chloride having good physical properties such as initial colorability, heat stability, fish eye and plasticizer absorbability with high productivity.

[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 For example, a method using a more active polymerization initiator has been adopted. However, when a large amount of the polymerization initiator is used, the initial coloring property and heat stability of the obtained polyvinyl chloride are deteriorated and the commercial value is lowered, so that there is a limitation in shortening 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, acetylcyclohexylsulfonyl peroxide (hereinafter abbreviated as ACSP) and diisobutyryl peroxide (hereinafter abbreviated as IBPO) (Japanese Patent Laid-Open No. 54-11190). ) Etc. are known. Further, cumyl peroxy neodecanoate (hereinafter abbreviated as CND) is used as a peroxy ester derived from a tertiary carboxylic acid represented by neodecanoic acid (JP-A-58-1).
20611), t-octyl peroxy neodecanoate (hereinafter abbreviated as OND) (JP-A-58-1).
20613) and 1,1,2-trimethylpropyl peroxy neodecanoate (JP-A-5-10570).
No. 8) (hereinafter abbreviated as TMPND) and the like are also known.

However, these conventional high activity polymerization initiators also have the following problems in terms of their activity and the physical properties of the obtained polyvinyl chloride. That is,
ACSP has poor physical properties such as heat stability, fish eye and plasticizer absorption of the obtained polyvinyl chloride.
O 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. Furthermore, since it has an aromatic ring in the structure, a UV absorption peak appears in the extraction test of the obtained polyvinyl chloride,
There is a problem that applications to the medical and food fields are limited. Unlike CND, OND and TMPND are non-aromatic peroxyesters, and therefore, they are C
The odor problem of ND can be solved, and polyvinyl chloride having relatively good physical properties can be obtained. However, its activity is still inferior to that of ACSP, IBPO, and CND, so that it was still unsatisfactory in that high-speed polymerization was achieved.

[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 having no aromatic ring in the molecule, there is no odor, and initial colorability, heat stability, and fish are obtained. It is an object of the present invention to provide an improved method for polymerizing vinyl chloride, which makes it possible to obtain polyvinyl chloride having good physical properties such as eye and plasticizer absorbability with high productivity.

[0007]

DISCLOSURE OF THE INVENTION As a result of long-term research on the problems of the above-mentioned conventional method, the present inventors have solved all the problems of conventional initiators by using the following polymerization initiators. The present invention has been completed after confirming that it is possible.

That is, according to the present invention, the general formula (A) is used as a polymerization initiator when polymerizing a vinyl chloride monomer.

[Chemical 3] 1-methylcyclohexyl peroxyneoalkanoate represented by the formula (A) or (B) in combination with a polymerization initiator having a 10-hour half-life temperature in benzene of 0.1 mol / L of 33 to 65 ° C. A method for polymerizing vinyl chloride, characterized in that

Specific examples of 1-methylcyclohexylperoxyneoalkanoate represented by the chemical formula 1 used in the present invention include 1-methylcyclohexylperoxyneodecanoate, 1-methylcyclohexylperoxypivalate, 1- Methyl cyclohexyl peroxy neohexanoate, 1-methyl cyclohexyl peroxy neo heptanoate, 1-methyl cyclohexyl peroxy neo octanoate, 1-methyl cyclohexyl peroxy neononanoate, 1-methyl cyclohexyl peroxy neo tridecanoate, etc. You can

The 1-methylcyclohexylperoxyneoalkanoate represented by the above (formula 1) can be obtained, for example, by a conventional means as shown below. That is,
Carboxylic acid chloride and 1-methylcyclohexyl hydroperoxide can be obtained under the same reaction conditions as conventional peroxyesters using sodium hydroxide, potassium hydroxide or amines such as pyridine as a catalyst. That is, as a solvent, an aliphatic hydrocarbon (for example, pentane, hexane, octane, petroleum naphtha, mineral spirits) or an aliphatic hydrocarbon containing isoparaffin as a main component (for example, trade name "Shellsol"; manufactured by Shell Chemical Co.) or aromatic It can be synthesized using a hydrocarbon (for example, toluene, ethylbenzene) or diluted after the synthesis. The reaction temperature is about -10 ° C to 30 ° C.

The above-mentioned carboxylic acid chloride is, for example, a chlorinating agent such as neodecanoic acid, pivalic acid, neohexanoic acid, neoheptanoic acid, neooctanoic acid, neononanoic acid, neotridecanoic acid, etc., such as phosgene or PCl.
It can be obtained by reacting ₃ , POCl ₃ , SOCl _2, etc.

The above-mentioned 1-methylcyclohexyl hydroperoxide is prepared by air oxidation of methylcyclohexane, or of a strong acid catalyst such as sulfuric acid, phosphoric acid, perchloric acid, an acid form of an ion exchange resin or p-toluenesulfonic acid. In the presence, 1-methylcyclohexanol can be prepared by treating with excess hydrogen peroxide.

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

When 1-methylcyclohexyl peroxyneoalkanoate represented by the formula (1) is used as a polymerization initiator for vinyl chloride-based monomers, the addition amount thereof is generally 100. The amount is 0.001 to 1 part by weight, preferably 0.005 to 0.5 part by weight, based on the weight of pure product. The amount is 0.001
If it is less than part by weight, the polymerization rate tends to be slow. On the other hand, if it exceeds 1 part by weight, it becomes difficult to control the polymerization reaction and the physical properties of the obtained polymer tend to be deteriorated, which is not preferable.

A polymerization initiator (B) having a 10-hour half-life temperature of 33 to 65 ° C. in 0.1 mol / L in benzene used together with the above-mentioned 1-methylcyclohexylperoxyneoalkanoate (A) in the present invention. Specifically, for example, t-butylperoxy neodecanoate (10-hour half-life temperature (hereinafter the same) 47 ° C.), t-hexyl peroxy neodecanoate (45 ° C.), TMP
ND (42 ° C), 1-cyclohexyl-1-methylethylperoxyneodecanoate (41 ° C), OND (4
1 ° C.), CND (37 ° C.), α, α′-bis (neodecanoylperoxy) diisopropylbenzene (36
C), t-butyl peroxypivalate (55 C), t
Peroxyesters such as hexyl peroxypivalate (53 ° C.), further dialkyl peroxydicarbonates such as bis (2-ethylhexyl) peroxydicarbonate (43 ° C.), diisopropyl peroxydicarbonate (41 ° C.), and further IBPO (33 ℃),
3,5,5-Trimethylhexanoyl peroxide (6
0 ° C.), lauroyl peroxide (62 ° C.), octanoyl peroxide (62 ° C.) diacyl peroxide, and the like.

One or more of these 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, and as described above, 1-methylcyclohexylperoxyneo. Used as a polymerization initiator in combination with alkanoate (A).

(A) when used in combination,
The mixing ratio and the amount of both components (B) are appropriately determined according to the reaction conditions, but the mixing ratio is usually (A) :( B) = 1.
It is 0: 0 to 1: 9 parts by weight.

The polymerization method used in the present invention may be ordinary suspension polymerization or emulsion polymerization, and the polymerization temperature is generally 20 to 80 ° C, preferably 30 to 70 ° C. If the polymerization temperature is lower than 20 ° C, the polymerization time tends to be long, and if it exceeds 80 ° C, the life of the polymerization initiator is shortened, and it is difficult to reach a high polymerization conversion rate, which is not preferable.

The present invention has the following features. That is, 1-methylcyclohexyl peroxy neoalkanoate represented by the chemical formula (1) has a characteristic that the decomposition half-life is shorter than that known in the prior art as a non-aromatic peroxy ester. That is, when compared with peroxyesters derived from the same carboxylic acid, other t-alkyl hydroperoxides such as t-butyl hydroperoxide, t-amyl hydroperoxide, t-octyl hydroperoxide and 1,
It has a faster decomposition rate than peroxyesters derived from 1,2-trimethylpropyl hydroperoxide and the like.
Therefore, the method of the present invention has a higher polymerization rate than the conventional method using a polymerization initiator. Furthermore, the polymerization method of the present invention can provide a vinyl chloride polymer having good physical properties such as initial colorability, thermal stability, fish eye, and plasticizer absorbability with high productivity, as compared with a method using a conventional polymerization initiator. To be Moreover, since the obtained polymer does not have an odor due to a decomposed product of peroxide, it is preferable in view of the working environment when a plastic product is added to the polymer and kneaded to produce a soft product. In addition, the 1-methylcyclohexylperoxy neoalkanoate used in the present invention exhibits sufficient activity even in low temperature polymerization (polymerization temperature of 50 ° C. or lower) carried out to obtain a vinyl chloride polymer having a high degree of polymerization. The polymerization method of the present invention can remarkably improve the productivity in producing a high degree of polymerization product.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Production of 1-Methylcyclohexylperoxyneoalkanoate) Reference Example 1 33.7 g of 30% potassium hydroxide aqueous solution was placed in a 200 ml four-necked flask equipped with a stirrer, and the liquid temperature was adjusted to 10 with stirring.
A mixture of 14.5 g of 1-methylcyclohexyl hydroperoxide having a purity of 99% and 30 g of benzene was added while maintaining the temperature at ℃. Further, with stirring, 19.1 g of neodecanoic acid chloride was added dropwise over 7 minutes while maintaining the liquid temperature at 15 ° C. After the liquid temperature was raised to 25 ° C. and stirring was continued for 2 hours, 40 g of cold water was added and the mixture was further stirred for 5 minutes. Aqueous phase separated, 5%
It was washed with 40 g of an aqueous sodium hydroxide solution and then with water three times. After drying this solution over anhydrous magnesium sulfate, benzene was removed under vacuum. As a result, a pale yellow liquid 22.
9 g was obtained. It was confirmed by IR and NMR that this liquid was the desired 1-methylcyclohexyl peroxyneodecanoate. The amount of active oxygen is 5.52
%, The calculated purity is 98%, and the yield is 79 mol%.
Met.

Reference Examples 2 to 5 In the same manner as in Reference Example 1, the corresponding carboxylic acid chlorides were reacted with 1-methylcyclohexyl hydroperoxide, and the reaction products obtained were respectively 1-methylcyclohexyl peroxypivalate. , 1-methylcyclohexyl peroxy neoheptanoate, 1-methyl cyclohexyl peroxy neononanoate, and 1-methyl cyclohexyl peroxy neotridecanoate.

(Measurement of 10-hour half-life temperature (T ₁₀ )) A thermal decomposition test was conducted using benzene as a solvent (concentration: 0.
1 mol / L). The 10-hour half-life temperature (T ₁₀ ) was determined for the 1-methylcyclohexyl peroxyneoalkanoate used in the present invention and known peroxyesters synthesized in Reference Examples 1 to 5. The above results are shown in Table 1.

[0024]

[Table 1]

From this result, the 1-methylcyclohexyl peroxyneoalkanoate used in the present invention was confirmed to be the prior art t-octyl peroxy ester and 1,1,2-
It can be seen that the decomposition rate is faster than that of trimethylpropyl peroxy ester.

(Polymerization of vinyl chloride) Next, a vinyl chloride monomer was polymerized by the method of the present invention. The abbreviations of the polymerization initiators used in Examples and Comparative Examples, their chemical names, and the 10-hour half-life temperature at 0.1 mol / L in benzene are shown.

(1-Methylcyclohexylperoxyneoalkanoate) MCND: 1-Methylcyclohexylperoxyneodecanoate (38 ° C.) MCPV: 1-Methylcyclohexylperoxypivalate (47 ° C.) MCHP: 1-Methylcyclohexylperoxyneohepta Noate (45 ° C.) MCN: 1-Methylcyclohexylperoxyneononaate (37 ° C.) MCTD: 1-Methylcyclohexylperoxyneotridecanoate (38 ° C.) (In coexistence with 1-methylcyclohexylperoxyalkanoate (B) Polymerization Initiator Shown) BND: t-Butyl Peroxyneodecanoate (4
7 ° C.) HPV: t-hexyl peroxypivalate (53
C) OPP: Bis (2-ethylhexyl) peroxydicarbonate (43C) IBPO: Diisobutyryl peroxide (33C) (Polymerization initiator used in Comparative Examples) ACSP: Acetylcyclohexylsulfonyl peroxide (27C) IBPO: Diisobutyryl peroxide (33 ° C.) CND: cumyl peroxyneodecanoate (37
C) OND: t-octyl peroxy neodecanoate (41 C) TMPND: 1,1,2-trimethylpropyl peroxy neodecanoate (42 C)

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, 0.040 g of M in terms of pure product
CND was added, cooled to -80 ° C or lower, and 100 g of vinyl chloride monomer was added. The space in the autoclave was thoroughly replaced with nitrogen gas, and the container was sealed. It was immersed in a constant temperature water bath kept at 50 ° C. for 6 hours for polymerization. The stirring was carried out by using an autoclave in a water tank at 32 r. p. m. It was carried out by rotating with. After polymerization, the mixture was cooled, unreacted vinyl chloride monomer was removed, and 100 ml of the obtained white powder was obtained.
It was washed twice with water and 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 the dry weight of the vinyl chloride polymer obtained in each experiment. As a result, the conversion rate is 84.9%
And the average degree of polymerization was 1430.

The physical properties of the obtained vinyl chloride polymer were tested on the following items. Table 2 shows the respective results
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, Ba-Zn system 1 part 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. ○: No odor △: Weak odor ×: Strong odor [Fish eye] To 50 parts by weight of vinyl chloride polymer, 25 parts by weight of dioctyl phthalate and 2 parts by weight of stabilizer were added and mixed, and then each was kneaded with a roll at 140 ° C. for 5 minutes. The number of fish eyes found in 100 cm ^{2 of the} thus obtained sheet having a thickness of 0.3 mm was shown. [Plasticizer absorbency] To 10 parts by weight of a vinyl chloride polymer, 20 parts by weight of dioctyl phthalate was added as a plasticizer, 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 the plasticizer.

Examples 2 to 10 Using the polymerization initiators shown in Table 2, the vinyl chloride monomer was polymerized according to Example 1 at the polymerization temperatures shown in Table 2.
The results are shown in Table 2, respectively.

Example 11 Same as Example 1 except that 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 amount of MCND added was 0.045 g. Polymerization was carried out. The results are shown in Table 2, 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 2 except that D and TMPND were used alone. The results are shown in Table 2, respectively.

Comparative Examples 7 and 8 Vinyl chloride monomers were polymerized according to Example 1 under the conditions shown in Table 2 except that IBPO or CND and OPP were used in combination as the polymerization initiator. The results are shown in Table 2, respectively.

[0034]

[Table 2]

Claims (2)

[Claims] 1. When polymerizing a vinyl chloride-based monomer,
General formula as a polymerization initiator A method for polymerizing vinyl chloride, which comprises using 1-methylcyclohexyl peroxyneoalkanoate represented by 2. When polymerizing a vinyl chloride-based monomer,
As the polymerization initiator, (A) the general formula: Polymerization of vinyl chloride characterized by using 1-methylcyclohexyl peroxyneoalkanoate represented by the formula (1) and (B) a polymerization initiator having a 10-hour half-life temperature of 33 to 65 ° C. in 0.1 mol / L in benzene. Method.