JPH1025311A - Polymerization initiator for vinyl chloride-based monomer and production of vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject initiator consisting of a specific compound, capable of shortening the polymerization time of a vinyl chloride-based monomer while maintaining high polymer yield, and capable of improving the thermal stability of, and reducing the discoloration, odor and fish-eye of the resultant vinyl chloride-based polymer. SOLUTION: This polymerization initiator consists of (A) a neooctanoic acid peroxyester predominant in a peroxyester of formula I (R is a 1-5C alkyl, cyclohexyl or phenyl)(e.g. t-butylperoxy-2-methyl-2-isopropyl butyrate). It is preferably that this initiator is used in combination with another polymerization initiator at 25-65 deg.C at which its half-life determined in the form of a benzene solution at a concentration of 0.1mol cones to 10h (e.g. cumyl peroxyneodecanoate).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymerization initiator effective for polymerizing a vinyl chloride monomer and a method for producing a vinyl chloride polymer using the polymerization initiator. Specifically, it is possible to shorten the polymerization time and to obtain a vinyl chloride polymer having excellent physical properties such as odor, coloring properties and fish eyes. Production of a vinyl chloride monomer polymerization initiator and a vinyl chloride polymer It is about the method.

[0002]

2. Description of the Related Art In polymerizing a vinyl chloride monomer,
As a polymerization initiator, t-butyl peroxy neodecanoate (hereinafter abbreviated as BND), bis (2-
Ethylhexyl) peroxydicarbonate (hereinafter referred to as O
PP), 3,5,5-trimethylhexanoyl peroxide (hereinafter abbreviated as INPO), t-octylperoxy neodecanoate and the like are used. The temperature at which the half-life of a 0.1 molar solution of these polymerization initiators in benzene is 10 hours (hereinafter, referred to as the temperature).
Abbreviated as 10 hour half-life temperature) is 45 to 6
It falls within the range of 0 ° C.

[0003] Therefore, when these are used for the polymerization of vinyl chloride-based monomers, it is economically disadvantageous that a relatively high polymerization temperature is required, and unless a considerably large amount is used, the polymerization is not completed. There was a big problem. In order to improve this point and shorten the polymerization cycle to increase the productivity, diisobutyryl peroxide (hereinafter referred to as I)
Lower temperature active polymerization initiators such as BPO) have been developed and have been used alone or in combination with conventional polymerization initiators.

[0004] Such low temperature active polymerization initiators include:
Specifically, IBPO, acetylcyclohexylsulfonyl peroxide (hereinafter abbreviated as ACSP) (JP-A-40-16795) and cumylperoxy neodecanoate (hereinafter abbreviated as CND) (JP-A-58-1983) 1
No. 20611) have a 10-hour half-life temperature of 40 ° C. or less.

Further, Japanese Patent Publication No. 59-14481 discloses a method for polymerizing a vinyl monomer with a tertiary alkyl peroxyester. This polymerization initiator is
The acyl group has an alkyl group having up to 11 carbon atoms, at most one of which is a tertiary carboxyl group which is a methyl group, and the alkylperoxy group side is a tertiary alkyl peroxide having up to 7 carbon atoms.

[0006] Also, JP-A-3-20309 discloses that
A method for polymerizing a vinyl monomer with a peroxyester of a tertiary fatty acid having two isopropyl groups at the α-position is disclosed.

[0007]

However, these conventional low-temperature active polymerization initiators cannot be said to have sufficient activity at low temperatures, and the effect of shortening the polymerization time is small. For this reason, a polymerization initiator having high polymerization efficiency is desired.

At the same time as the improvement of productivity, the quality of the polymer has recently been particularly emphasized. A polymerization initiator which not only has high activity but also improves the quality of the polymer has been desired. ing.

As described above, the conventional low-temperature active polymerization initiators have problems in improving the productivity and the quality of the polymer. That is, IBPO has no sustained polymerization activity, and ACSP has problems of hygiene of decomposition products and heat stability such as coloring of the obtained polymer. Furthermore, CND is an excellent polymerization initiator in terms of polymerizability, but has a drawback that when it is used in a large amount, it has an odor peculiar to the polymer, especially due to decomposition products.

The tertiary alkyl peroxyesters disclosed in JP-B-59-14481 and JP-A-3-20309 have a remarkable decrease in polymerization activity after the start of pressure drop in the latter half of polymerization. Therefore, the polymerization conversion could not be sufficiently increased. Therefore, a peroxide having a low activity and a high activity in the latter half of the polymerization is desired.

The present invention has been made by paying attention to such a problem existing in the prior art. The aim is to shorten the polymerization time while maintaining high yield, and to improve the physical properties such as colorability, odor, fisheye, and thermal stability of the resulting vinyl chloride polymer. An object of the present invention is to provide a polymerization initiator of a vinyl chloride-based monomer and a method for producing a vinyl chloride-based polymer.

Another object is to use a vinyl chloride-based monomer capable of promoting polymerization at a uniform rate and shortening the polymerization cycle by using other polymerization initiators in combination. And a method for producing a vinyl chloride polymer.

[0013]

Means for Solving the Problems In order to achieve the above object, a polymerization initiator of a vinyl chloride monomer according to the first invention comprises:
It is composed of neooctanoic acid peroxyester containing a peroxyester represented by the following general formula (1).

[0014]

Embedded image (In the formula, R represents a linear or branched alkyl group having 1 to 5 carbon atoms, a cyclohexyl group or a phenyl group.) The polymerization initiator of the vinyl chloride monomer of the second invention is the following.
The invention further comprises a polymerization initiator having a temperature at which the half-life measured at a 0.1 molar concentration in benzene of 10 hours is 25 to 65 ° C.

The method for producing a vinyl chloride polymer according to the third invention uses the polymerization initiator according to the first or second invention as a polymerization initiator to polymerize a vinyl chloride monomer.

[0016]

Embodiments of the present invention will be described below in detail. First, a polymerization initiator used when polymerizing a vinyl chloride monomer will be described.

The polymerization initiator is a peroxyester-containing neooctanoic acid peroxyester represented by the general formula (1). In the formula, R is carbon number 1
5 represents a linear or branched alkyl group, a cyclohexyl group or a phenyl group. Neooctanoic acid peroxyester desirably contains a peroxyester represented by the general formula (1) as a main component in order to sufficiently exhibit the ability to initiate polymerization of a vinyl chloride monomer.

Although this peroxyester has an unclear effect, it exhibits activity at a low temperature upon polymerization of a vinyl chloride monomer based on the unique structure represented by the general formula (1).

As the peroxyester, specifically, for example, t-butylperoxy-2-methyl-2-
Isopropyl butyrate, t-amyl peroxy-2-
Methyl-2-isopropylbutyrate, t-hexylperoxy-2-methyl-2-isopropylbutyrate,
t-octylperoxy-2-methyl-2-isopropylbutyrate, 1-methyl-1-cyclohexylethylperoxy-2-methyl-2-isopropylbutyrate, cumylperoxy-2-methyl-2-isopropylbutyrate, etc. No. Of these, t-butylperoxy-2-methyl-2-isopropylbutyrate is preferred because it is easily available and inexpensive.

The peroxyester can be produced by reacting a tertiary hydroperoxide with 2-methyl-2-isopropylbutyryl chloride in the presence of an alkali catalyst. The tertiary hydroperoxide used includes t-butyl hydroperoxide, t-amyl hydroperoxide, t-hexyl hydroperoxide, t-octyl hydroperoxide,
-Methyl-1-cyclohexylethyl hydroperoxide, cumyl hydroperoxide and the like. Also,
As the alkali catalyst, sodium hydroxide, potassium hydroxide or the like is used. Further, the reaction temperature is usually 10 to 3
0 ° C.

2-Methyl-2-isopropylbutyryl chloride is, for example, neooctanoic acid [2-methyl-2-
Mixtures of neooctanoic acid based on isopropyl butyric acid, such as Exxon Chemical (Exxon
Chemical Co., Ltd.] is chlorinated with thionyl chloride or the like.

Next, a method for producing a vinyl chloride polymer using the above polymerization initiator will be described. The vinyl chloride monomer refers to vinyl chloride alone or a mixture of vinyl chloride and vinyl chloride copolymerizable with vinyl chloride. Examples of the vinyl monomer copolymerizable with vinyl chloride include ethylene, vinyl acetate, vinylidene chloride, styrene, acrylates, and the like.

The amount of the polymerization initiator to be used is usually preferably 0.001 to 2 parts by weight, and more preferably 0.01 to 1 part by weight in terms of a pure product, based on 100 parts by weight of the vinyl chloride monomer used. preferable. If the amount is less than 0.001 part by weight, the polymerization rate will decrease, and if it exceeds 2 parts by weight, the polymerization rate will increase and it will be difficult to control the rate.

As the polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method and the like are employed, and the suspension polymerization method is preferred because a vinyl chloride polymer powder can be easily obtained. The suspension polymerization method is a method in which polymerization is performed in a state where a vinyl chloride monomer is dispersed in water with a suspending agent. The polymerization temperature in this polymerization method is preferably from 40 to 65 ° C. If the temperature is lower than 40 ° C., the polymerization rate is decreased, and if the temperature is higher than 65 ° C., the polymerization rate is increased and it becomes difficult to control the polymerization rate.

The peroxyester-containing neooctanoic acid peroxyester represented by the general formula (1) as the above-mentioned polymerization initiator can be used alone or in addition to the polymerization initiator in a concentration of 0.1 mol / liter in benzene. Is used in combination with a polymerization initiator having a 10-hour half-life temperature (hereinafter referred to as T10) of 25 to 65 ° C., the half-life of which is measured in 10 hours. In this case, the polymerization can proceed at a relatively uniform rate from the initial stage to the latter half of the polymerization, and the polymerization cycle can be shortened. Therefore, the vinyl chloride monomer can be efficiently polymerized using a cooling device having a limited capacity.

Examples of the polymerization initiator that can be used in combination include cumyl peroxy neodecanoate (T10 = 36 ° C.),
Di (t-butylperoxy) diglycolate (T10 =
34 ° C.), di (t-hexylperoxy) diglycolate (T10 = 32 ° C.), t-octylperoxydiglycolate (T10 = 28 ° C.), t-hexylperoxypivalate (T10 = 52 ° C.), t-butylperoxy Neoheptanoate (T10 = 52 ° C.), lauroyl peroxide (T10 = 62 ° C.), 3,5,5-trimethylhexanoyl peroxide (T10 = 59 ° C.) and the like.

Of these, cumyl peroxy neodecanoate and di (t-hexyl peroxy) diglycolate are more preferable because of their high polymerization rate and good physical properties such as initial coloring. These peroxides are used in the form of a pure product, a solvent-diluted product, a water emulsion or a suspension.

The amounts of the peroxyester-containing neooctanoic acid peroxyester represented by the general formula (1) and the polymerization initiator used in combination therewith with a T10 of 25 to 65 ° C. are usually between 100% and 100%. 0.001 to 0.5 parts by weight in terms of a pure product with respect to parts by weight is preferable,
0.01 to 0.3 parts by weight is more preferred. 0.001
If the amount is less than part by weight, the effect of initiating polymerization is insufficient, and if it exceeds 0.5 part by weight, the function of neooctanoic acid peroxyester as a polymerization initiator is undesirably reduced.

The effects exerted by the above embodiment will be described. (1) Since the peroxyester having the specific structure represented by the general formula (1) is used as the polymerization initiator, the polymerization efficiency can be increased, and the generation of by-products can be suppressed.
A vinyl chloride polymer can be obtained in high yield. (2) The peroxyester represented by the general formula (1) exhibits sufficient polymerization activity, particularly high polymerization initiation efficiency in the latter half of polymerization, and can efficiently polymerize a vinyl chloride monomer,
The polymerization time can be shortened. (3) Since the peroxyester having a specific structure represented by the general formula (1) is used, the coloring property of the obtained vinyl chloride polymer can be suppressed. (4) By using the specific peroxyester represented by the general formula (1), the odor of the obtained vinyl chloride polymer can be suppressed. (5) Since the peroxyester having a specific structure represented by the general formula (1) is used, fish eyes in the obtained vinyl chloride polymer can be reduced. (6) The vinyl chloride monomer can be efficiently polymerized at a low temperature, and the thermal stability of the vinyl chloride polymer can be improved. (7) As the polymerization initiator, a peroxyester-containing neooctanoic acid peroxyester represented by the general formula (1) is used in combination with another polymerization initiator having a 10-hour half-life temperature of 25 to 65 ° C. The polymerization can be allowed to proceed at a uniform rate from the initial stage to the latter stage of the polymerization of the vinyl chloride monomer. (8) Therefore, the polymerization cycle of the vinyl chloride monomer can be shortened, and the vinyl chloride monomer can be efficiently polymerized using a cooling device having a limited capacity.

[0030]

Next, the present invention will be described more specifically with reference to Synthesis Examples, Examples and Comparative Examples. In addition, the abbreviation in each example shows the following compounds.

BMIB: Neooctanoic acid peroxyester containing t-butylperoxy-2-methyl-2-isopropylbutyrate as a main component HMIB: t-hexylperoxy-2-methyl-2-methyl-2-octanoate
Neooctanoic acid peroxyester based on isopropyl butyrate OMIB: t-octylperoxy-2-methyl-2-
Neooctanoic acid peroxyester having isopropylbutyrate as a main component CMIB: Cumylperoxy-2-methyl-2-isopropylbutyrate neooctanoic acid peroxyester BDIB: t-butylperoxy-2,3-dimethyl-
2-isopropylbutyrate CND: cumylperoxy neodecanoate HDG: di (t-hexylperoxy) diglycolate ACSP: acetylcyclohexylsulfonyl peroxide IBPO: isobutyryl peroxide INPO: 3,5,5-trimethylhexanoyl peroxide OPP: Bis (2-ethylhexyl) peroxydicarbonate BNHP: t-butylperoxyneoheptanoate (Synthesis Example 1, Synthesis of BMIB) A polymerization initiator BMIB was synthesized by the following method.

240 g of a 35% aqueous potassium hydroxide solution was placed in a 1000 ml four-necked flask equipped with a stirrer, and 154 g of 70% t-butyl hydroperoxide was added while maintaining the liquid temperature at 15 ° C. with stirring. Thereafter, neooctanoic acid 162. Neooctanoic acid chloride produced by chlorinating neooctanoic acid [a neooctanoic acid mixture containing 81% of 2-methyl-2-isopropylbutyric acid, manufactured by Exxon Chemical Co.] with thionyl chloride at the same temperature. 5 g was added dropwise over 30 minutes. Next, the liquid temperature was raised to 20 ° C., and stirring was continued for 1 hour.

Thereafter, 200 g of cold water was added, and the mixture was stirred for 5 minutes, separated, and an oil layer was collected. Then, after washing with a 5% aqueous sodium hydroxide solution, washing was performed three times with water. This was dried over anhydrous magnesium sulfate and filtered. as a result,
204 g were obtained as a colorless transparent liquid. This compound
From the results of infrared absorption spectrum analysis (IR) and nuclear magnetic resonance spectrum analysis (NMR), it was confirmed that the substance was BMIB. From the measurement result of active oxygen, BMIB having a purity of 95% was obtained in a yield of 90%. (Synthesis Example 2, Synthesis of HMIB)
Instead of 154 g of% t-butyl hydroperoxide,
The procedure was performed according to Synthesis Example 1 except that 157 g of 90% t-hexyl hydroperoxide was used. As a result, 239 g of a colorless transparent liquid was obtained. This compound was confirmed to be HMIB from the results of IR and NMR analysis. Also, from the measurement result of active oxygen, HM of 94% purity was obtained.
IB was obtained in 92% yield. (Synthesis Example 3, Synthesis of OMIB)
Instead of 154 g of% t-butyl hydroperoxide,
The procedure was performed in the same manner as in Synthesis Example 1 except that 162 g of 90% t-octyl hydroperoxide was used. As a result, 254 g was obtained as a colorless transparent liquid. This compound was confirmed to be OMIB from the results of IR and NMR analysis. Also, from the measurement result of active oxygen, OM having a purity of 91% was obtained.
IB was obtained in a yield of 85%. (Synthesis Example 4, Synthesis of CMIB)
Instead of 154 g of% t-butyl hydroperoxide,
The procedure was performed in the same manner as in Synthesis Example 1 except that 167 g of 91% cumene hydroperoxide was used. As a result, 262 g of a colorless transparent liquid was obtained. This compound has IR and NM
From the result of R analysis, it was confirmed that the substance was CMIB. From the measurement result of active oxygen, CMIB having a purity of 89% was obtained with a yield of 84%. (Example 1) Content 500 with pressure gauge and stirrer
In a 0 ml stainless steel autoclave, 2000 ml of ion-exchanged water and 1 g of polyvinyl alcohol were put and dissolved. Next, after adding 0.5 g of BMIB obtained in Synthesis Example 1 in terms of a pure product, the mixture was cooled to −70 ° C. or lower, and 1000 g of a vinyl chloride monomer was added. The space in the autoclave was replaced with nitrogen gas and sealed.

The autoclave was kept warm with hot water, and while the internal temperature was kept at 55 ° C., polymerization was continued until the pressure inside the autoclave began to decrease and further decreased to 6.0 atm. As a result, it was 3.5 hours when the pressure began to drop, and the final time was 4.0 hours. The mixture after polymerization was filtered, washed with water and dried. Then, 820 g of a polymer was obtained.

As a thermal stability test of the obtained vinyl chloride polymer, a coloring test shown below was carried out, and at the same time, an odor was examined. A fisheye test was also performed. The results are shown in Table 1 below. (Coloring test and odor) 100 g of vinyl chloride polymer, 50 g of dioctyl phthalate and 2.5 g of dibutyltin maleate were mixed, kneaded on a roll at 160 ° C. for 10 minutes, and a 1 mm thick sheet was taken out. Was visually observed. Further, the odor of the obtained sheet was examined. (Fisheye) 20 g of dioctyl phthalate, 50 g of vinyl chloride polymer, and barium (Ba) -zinc (Z
n) After adding and mixing 2 g of the system stabilizer and 3 g of the pigment,
The mixture was kneaded with a roll at 140 ° C. for 5 minutes. Then, the number of fish eyes observed in 100 cm ^{2 of} the obtained 0.3 mm thick sheet is shown. (Examples 2 to 4) Tests were performed in the same manner as in Example 1 except that the peroxides shown in Table 1 were used instead of BMIB. Table 1 shows the results. (Examples 5 to 12) The tests were conducted in the same manner as in Example 1 except that the peroxides shown in Tables 1 and 2 were used in place of BMIB and the polymerization temperature was changed. The results are shown in Tables 1 and 2. (Comparative Examples 1 to 6) The test was performed in the same manner as in Example 1 except that the peroxides shown in Table 3 were used instead of the BMIB. Table 3 shows the results.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3] As shown in Tables 1 to 3, when Examples 1 to 4 and 7 to 12 embodying the present invention are compared with conventional Comparative Examples 1 to 3 and 5, in each Example, the polymerization was completed compared to the Comparative Example. Time was saved. In particular, it can be seen that the time from the pressure drop time to the polymerization end time can be reduced. Therefore, it is possible to extend the time for performing the heat removal in the first half of the polymerization with respect to the total polymerization time. For this reason, the polymerization of vinyl chloride which generates heat can be performed with a relatively small heat removal (cooling) capacity, and the capacity of the cooling device can be reduced.

Further, when Examples 1 to 4 are compared with Comparative Example 4, it can be seen that in each Example, a polymer having less coloring property and less fish eye can be obtained than the Comparative Example. Further, when Examples 1 to 4 are compared with Comparative Example 6, it can be seen that in each Example, a polymer having less odor and less fish eyes than the Comparative Example can be obtained.

Further, when a polymerization initiator having a low temperature activity was used in combination (Examples 5 and 6), the polymerization could proceed at a uniform rate and the polymerization cycle could be shortened.

In addition, comparing Example 5 with Comparative Example 6, it can be seen that the odor perceived when using CND alone (Comparative Example 6) can be reduced when using BND in combination with CND (Example 5). did it.

Next, the technical ideas grasped from the above embodiment will be described below. (A) The polymerization initiator of a vinyl chloride monomer according to claim 1, wherein the neooctanoic acid peroxyester contains a peroxyester represented by the general formula (1) as a main component.

With such a constitution, the physical properties such as the coloring property, odor, fish eye and thermal stability of the vinyl chloride polymer can be surely improved. (B) The method for producing a vinyl chloride polymer according to claim 3, wherein the polymerization is performed by a suspension polymerization method.

According to this method, a vinyl chloride polymer having desired physical properties can be easily obtained. (C) The peroxyester represented by the general formula (1) is composed of tertiary hydroperoxide and 2-methyl-2-
The polymerization initiator for a vinyl chloride-based monomer according to claim 1, which is obtained by reacting isopropylbutyryl chloride with an alkali catalyst.

In this case, the peroxyester represented by the general formula (1) can be obtained efficiently. (D) The polymerization initiator for a vinyl chloride monomer according to the above (c), wherein the alkali catalyst is sodium hydroxide or potassium hydroxide.

According to this configuration, a peroxyester can be easily obtained. (E) The initiation of polymerization of the vinyl chloride monomer according to claim 1, wherein the vinyl chloride monomer is vinyl chloride alone or a mixture of a vinyl monomer copolymerizable with vinyl chloride and vinyl chloride. Agent.

According to this configuration, the polymerization initiator can be used even when a vinyl chloride monomer is copolymerized with another monomer, the coloring property and the odor are suppressed, and the vinyl chloride monomer having little fish eye is obtained. Coalescence can be obtained.

[0048]

As described above in detail, according to the present invention, the following excellent effects can be obtained. According to the vinyl chloride monomer polymerization initiator of the first invention, the polymerization time can be shortened while maintaining a high yield, and the coloring property and odor of the obtained vinyl chloride polymer can be improved. , Fish eye, heat stability and other physical properties can be improved.
Therefore, the industrial utility value is extremely high.

According to the second invention, in addition to the effects of the first invention, by using another polymerization initiator in combination, the polymerization can proceed at a uniform rate and the polymerization cycle can be shortened. Can be.

According to the method for producing a vinyl chloride polymer of the third invention, when the vinyl chloride monomer is polymerized by, for example, a suspension polymerization method to obtain the vinyl chloride polymer, The effect or the effect of the second invention can be easily achieved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Yo Nakata 1-2-2, Otokawa Gennaibayashi-cho, Handa-shi, Aichi Prefecture 15 (72) Inventor Hiroki Uchida 8 West Gate, Taketoyo-cho, Chita-gun, Aichi Prefecture (72) Inventor Shuji Suyama 4-132 Kusunoki, Taketoyo-cho, Chita-gun, Aichi Prefecture

Claims (3)

[Claims] 1. A polymerization initiator of a vinyl chloride monomer comprising a peroxyester of neooctanoic acid containing a peroxyester represented by the following general formula (1). Embedded image (In the formula, R represents a linear or branched alkyl group having 1 to 5 carbon atoms, a cyclohexyl group or a phenyl group.) 2. The vinyl chloride monomer according to claim 1, further comprising a polymerization initiator having a temperature at which the half-life measured at 0.1 molar concentration in benzene of 10 hours is 25 to 65 ° C. Polymerization initiator. 3. A method for producing a vinyl chloride polymer, comprising polymerizing a vinyl chloride monomer using the polymerization initiator according to claim 1 or 2 as a polymerization initiator.