JPH0788402B2 - Polymerization method of vinyl chloride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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). The present invention relates to a method for polymerizing vinyl chloride.

(Prior Art) In the polymerization of vinyl chloride-based monomers, there is an automatic acceleration phenomenon in which the reaction rate rapidly increases when the polymerization reaction progresses to reach a high polymerization rate. At this time, since the heat generation is remarkable, the cooling capacity of the polymerization machine must be set according to the maximum heat generation amount at that time. As a result, prior to that point, the polymerizer was operating well below the maximum cooling capacity. For this reason, in order to maximize the cooling capacity of the polymerization machine, it has been conventionally desired to carry out polymerization with stable heat generation from the initial stage to the latter stage of the polymerization, so-called constant velocity polymerization.

Therefore, by using a fast-acting polymerization initiator showing a large reaction rate in the initial stage of the reaction and a slow-acting polymerization initiator showing a large reaction rate in the latter stage of the reaction in combination, a means for achieving uniform reaction rate is taken. Has been.

In this case, the slow-acting polymerization initiator is 0.
Temperature at which the half-life at 1 molar concentration is 10 hours (hereinafter, 1
0 hour half-life temperature (Hereinafter abbreviated) is in the range of 40 ~ 65 ℃ conventional polymerization initiators are used. Specifically, tertiary-butyl peroxy neodecanoate (hereinafter abbreviated as BND), 3,5,5
-Trimethylhexanoyl peroxide (hereinafter abbreviated as INPO), bis (2-ethylhexyl) peroxydicarbonate (hereinafter abbreviated as OPP) and the like.

And as a fast-acting polymerization initiator, the 10-hour half-life temperature is
A polymerization initiator having a temperature of 40 ° C or lower has been developed and used.
Specifically, acetylcyclohexyl sulfonyl peroxide (hereinafter abbreviated as ACSP), cumyl peroxy neodecanoate (hereinafter abbreviated as CND) and 1,1,3,3-
It is tetramethylbutyl peroxy neodecanoate (hereinafter abbreviated as OND).

(Problems to be Solved by the Invention) Constant-velocity polymerization becomes possible by adjusting the combination of the above-mentioned fast-acting polymerization initiator and slow-acting polymerization initiator, the mixing ratio of both, and the amount used. However, the physical properties of the obtained polymer were not always satisfactory. For example, ACSP suffers from hygiene issues with degradation products and poor thermal stability of the resulting polymer. In addition, CND has an odor characteristic of polymers due to its decomposition products. Furthermore, although OND has almost no problems with the physical properties of the polymer obtained, it is
Since it is inferior to ACSP and CND, it has a drawback that its effect as a fast-acting polymerization initiator is small.

(Means for Solving the Problems) The present inventors have studied the problems of the above-mentioned conventional methods for a long time, and as a result, by using a certain specific polymerization initiator, constant-velocity polymerization can be performed. The present invention has been completed by finding that the obtained polymer is also excellent in thermal stability, especially in colorability and has no odor.

That is, according to the present invention, when a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith are polymerized by using a polymerization initiator, (A) as a fast-acting polymerization initiator, 2,5- Bis (neodecanoylperoxy) -2,5-dimethylhexane and (B) Peroxy having a half-life of 10 hours in a 0.1 molar solution in benzene as a slow-acting polymerization initiator in the range of 40 to 65 ° C. A method for polymerizing vinyl chloride, characterized in that a polymerization initiator comprising at least one of ester, diacyl peroxide and peroxydicarbonate is used.

Other vinyl 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.

The fast-acting polymerization initiator, which is one component of the polymerization initiator used in the present invention, is 2,5-bis (neodecanoylperoxy) -2,5-dimethylhexane, and its addition amount is generally chloride. It is 0.001 to 0.5 parts by weight in terms of a pure product with respect to 100 parts by weight of the vinyl-based monomer charged, and preferably 0.01 to
0.2 parts by weight. If the amount is less than 0.001 part by weight, the polymerization rate will be slow.

On the other hand, if it exceeds 0.5 parts by weight, it becomes difficult to limit the polymerization reaction and the physical properties of the obtained polymer are deteriorated, which is not preferable.

2,5-bis (neodecanoylperoxy) -2,5-dimethylhexane reacts with 2,5-dimethylhexane-2,5-dihydroperoxide and neodecanoic acid chloride in the presence of an aqueous solution of potassium hydroxide, for example. Can be obtained by

The other component of the polymerization initiator used in the present invention is a slow-acting polymerization initiator, which is at least one kind of peroxy ester, diacyl peroxide and peroxydicarbonate having a 10-hour half-life temperature of 40 to 65 ° C. Is.

BND as a concrete peroxy ester (Hereinafter the same) = 46.5 ° C), tertiary-butylperoxy neohexanoate (52.1 ° C), tertiary-butylperoxypivalate (55 ° C), etc., as diacyl peroxide
INPO (59.5 ° C.), lauroyl peroxide (62 ° C.), octanoyl peroxide (62 ° C.), etc., and as peroxydicarbonate, OPP (43.5 ° C.), di (2-ethoxyethyl) peroxydicarbonate (43.4 ° C.), Di-n-propyl peroxydicarbonate (40.5 ° C.) and the like. The addition amount of these components is 1/4 to 4 times the addition amount of 2,5-bis (neodecanoylperoxy) -2,5-dimethylhexane.

The polymerization means used in the method of the present invention may be a usual suspension polymerization method or an emulsion polymerization method, and the polymerization temperature is generally 20 to
The temperature is 75 ° C, preferably 30 to 60 ° C. Polymerization temperature is 20
If it is less than ° C, the polymerization time tends to be long, and the life of the polymerization initiator exceeding 75 ° C is shortened, which is not preferable.

(Example) Hereinafter, the present invention will be described in more detail with reference to examples.

Reference Example (Synthesis of 2,5-bis (neodecanoylperoxy-2,5-dimethylhexane)) A 500 mL four-necked flask equipped with a stirrer was charged with 168.3 g of 20% aqueous potassium hydroxide solution, and the solution was stirred under stirring. While maintaining the temperature at 20 ° C., 35,6 g of 2,5-dimethylhexane-2,5-dihydroperoxide was added, and the liquid temperature was adjusted to 20 while stirring.
While keeping the temperature at 0 ° C, a mixed solution of 95.4 g of neodecanoic acid chloride and 30 g of an aliphatic hydrocarbon solvent (trade name "Cielsol 71" manufactured by Ciel Chemical Co., Ltd.) was added dropwise over 10 minutes. After continuing stirring for 1 hour as it was, the aqueous phase was separated. The oil phase was washed with 150 ml of a 5% aqueous sodium hydroxide solution and then with water three times. The solution was dried over anhydrous magnesium sulfate. As a result, 96.4 g of a 70.1% pure 2,5-bis (neodecanoylperoxy) -2,5-dimethylhexane sol-sol solution was obtained.

The yield was 69.3 mol%.

Example 1 A stainless steel autoclave having a capacity of 400 ml was charged with 200 ml of ion-exchanged water and 0.1 part by weight of polyvinyl alcohol,
Dissolved. Next, 2,5-bis (neodecanoylperoxy) -2,5-dimethylhexane obtained in Reference Example (hereinafter, 25N
(Abbreviated as D) is added 0.04 parts by weight in terms of pure product, BND is further added in an amount of 0.05 parts by weight in terms of pure product, cooled to −80 ° C. or lower, and 100 parts by weight of vinyl chloride monomer is added. . After sufficiently replacing the space of the autoclave with nitrogen gas,
It was sealed. This was immersed in a constant temperature water bath kept at 50 ° C. for 8 hours for polymerization. Stir the autoclave in a water bath for 32
It was carried out by rotating at rpm. These polymerization conditions are shown in Table 1. After the polymerization, it was cooled and the unreacted vinyl chloride monomer was removed.
It was washed twice with water and dried in vacuum. Calculated from the weight thus obtained, the yield of the vinyl chloride polymer was 90%.

As the heat stability test of the obtained vinyl chloride polymer, the following colorability test was performed, and at the same time, the odor was also tested. The results of each test are shown in Table 2.

(Coloring test) 100 parts by weight of vinyl chloride polymer, dibutyltin maleate 2.5
Parts by weight and 80 parts by weight of dioctyl phthalate as a plasticizer were mixed and kneaded on a roll at 160 ° C. for 10 minutes, a 1 mm thick sheet was taken out, and the degree of coloring of the sheet was visually observed.

Examples 2 and 3 As shown in Table 1, INP was used as a polymerization initiator instead of BND.
The vinyl chloride monomer was polymerized in the same manner as in Example 1 except that O and OPP were used respectively. The polymerization conditions and the polymer yield are shown in Table 1. In addition, the coloring test was conducted in the same manner as in Example 1, and the odor was also tested. The results are shown in Table 2.

Example 4 Copolymerization was carried out in the same manner as in 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. Table 1 shows the weight conditions and the yield of the copolymer at this time. In addition, the coloring test was conducted in the same manner as in Example 1, and the odor was also tested. The results are shown in Table 2.

Comparative Examples 1 to 3 Conventionally used in place of 25ND as a polymerization initiator
Polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that ACSP, CND and OND were used respectively. The polymerization conditions and the polymer yield are shown in Table 1. In addition, a coloring test was conducted in the same manner as in Example 1, and odor was also tested. The results are shown in Table 2.

As described above, as is clear from Tables 1 and 2, when the conventional polymerization initiator is used as the fast-acting heavy-duty initiator, the obtained polymer is obtained even when the same slow-acting polymerization initiator is used. Of the present invention has a problem that the coloring property (heat stability) is bad, has an odor, or both, or has a low yield even if the coloring property and the odor are good. Does not have these drawbacks at all.

The absence of coloration is advantageous during polymer processing.
Further, the absence of odor is preferable from the viewpoint of working environment during molding and processing.

(Effects of the Invention) The present invention using a specific polymerization initiator has the advantages described below.

That is, in the system using a polymerization initiator, compared to the method using a conventional initiator as a fast-acting polymerization initiator (for example, ACSP, CND), the obtained polymer has no odor, thermal stability, and is not particularly colored. Is excellent at.

In addition, conventional initiators (for example, ON
Compared to the method using D), the polymerization rate can be made uniform. Therefore, it is excellent in terms of polymer yield.

Therefore, the present invention is extremely useful industrially.

Claims (1)

[Claims] 1. When polymerizing a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith with a polymerization initiator, (A) 2,5-as a fast-acting polymerization initiator Bis (neodecanoylperoxy) -2,5-dimethylhexane and (B) Peroxy having a half-life of 10 hours in a 0.1 molar solution in benzene as a slow-acting polymerization initiator in the range of 40 to 65 ° C. A method for polymerizing vinyl chloride, which comprises using a polymerization initiator comprising at least one of ester, diacyl peroxide and peroxydicarbonate.