JPS6021689B2 - Polymer manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polymer having excellent heat resistance, impact resistance and processability while significantly suppressing the amount of reactive monomers.

Although Amo resin, which is an acrylonitrile-lucyrene-butadiene copolymer, is widely used as an excellent thermoplastic resin, it cannot be said to have sufficient heat resistance in the field of use.

It has been known for a long time that heat resistance can be improved by introducing Q-methylstyrene. A heat-resistant ABS resin made by mixing nitrile and styrene with a graft polymer obtained by grafting a rubbery polymer, and furthermore, Q-
Graft polymers in which methylstyrene and acrylonitrile are grafted have been proposed, but these are still insufficient, and there is a strong desire to develop polymers with better heat resistance. However, Q-alkylstyrene has poor reactivity in radical polymerization and remains as a large amount of unreacted monomer upon completion of polymerization.

Therefore, it is necessary to coexist a copolymerizable vinyl fist such as pinyl cyanide.

In order to obtain high heat resistance, it is necessary to use a large amount of Q-methylstyrene, but since the molar ratio of Q-methylstyrene and acrylonitrile abiotrobe is 1:1 (polymerization ratio 69:31), Q in the resulting copolymer
- The methylstyrene content will be much lower than the feed ratio. For example, when Q-methylstyrene:acrylonitrile is charged at a ratio of 90:10 and the polymerization is completed (no new copolymerization reaction occurs and the generation of polymerization heat stops), the rate of change to a copolymer is 55% by weight. It stops at about %.

The Q-methylstyrene content in the copolymer produced at this time was approximately 82% by weight, which was 9% by weight in the charging ratio.
- The methylstyrene content is considerably lower.

Further, at this time, Q-methylstyrene occupies almost all of the unreacted monomers in the polymerization tank, and acrylonitrile is almost completely absent. The amount of unreacted Q-methylstyrene remains at 45% by weight, which is about half of the 9% by weight used in the preparation. Since Q-methylstyrene does not polymerize alone, polymerization stops in this state where there is almost no acrylonitrile. As described above, as the ratio of Q-methylstyrene charged increases compared to the azeotrope composition, more Q-methylstyrene remains as an unreacted monomer.

Of course, if the polymer dispersion is stripped after completion of polymerization, a polymer with a high Q-alkylstyrene content can be obtained, but the reaction yield is significantly inferior.

Further, the stripping process requires equipment and a long time, which is not preferable. In view of these problems, the present inventors conducted intensive research on polymerization methods for rubbery polymers, Q-alkylstyrene, vinyl cyanide, and styrene, and found that by adjusting the method of adding each compound, heat-resistant The inventors discovered a method for producing a polymer with excellent properties, impact resistance, and processability while significantly suppressing the amount of unreacted monomer, and developed the present invention.

That is, the present invention includes 5 to 4 parts by weight of the rubbery polymer;
Emulsion polymerization of 95-6 parts by weight of a monomer consisting of 65-8% by weight of Q-alkylstyrene, 20-35% by weight of vinyl cyanide, and 0-1% by weight of styrene using a radical initiator. In this method, the entire amount of Q-alkylstyrene and a portion of vinyl cyanide are polymerized, and after the generation of new polymerization heat has stopped, the polymerization is performed using the Q-methylstyrene-vinyl cyanide copolymer and Q-methylstyrene as the main components. The present invention provides a method for producing a polymer, which comprises adding a rubber polymer and the remaining vinyl cyanide and styrene to carry out polymerization in the presence of unreacted monomers.

According to the present invention, a polymer having excellent not only heat resistance but also impact resistance and processability can be polymerized while significantly suppressing the amount of unreacted monomer. In particular, the amount of unreacted monomer can be suppressed to 1% by weight or less. The present invention will be explained in more detail.

Examples of the rubbery polymer used in the present invention include butadiene polymers, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, ethylene-propylene-diene polymers, and butadiene polymers are preferred. The polymer or styrene-butadiene copolymer has a styrene content of 4% by weight or less.

Q-alkylstyrene includes Q-methylstyrene,
Examples include Q-ethylstyrene and methyl-Q-methylstyrene, with Q-methylstyrene being preferred.

Examples of vinyl cyanide include acrylonitrile, methacrylnitrile, and ethacrylonitrile, with acrylonitrile being preferred. Examples of radical initiators include potassium persulfate, sodium persulfate, ammonium persulfate, cumene hydroperoxide, and diisopropylbenzenide.

Examples include peroxide redox, but preferably potassium persulfate or sodium persulfate, which are water-soluble initiators. Emulsifiers used in emulsion polymerization include:
Any conventional emulsifier can be used, but anionic emulsifiers are preferred, and sodium lauryl sulfate is particularly preferred. In the present invention, parts by weight of rubbery polymer 5-4 and 95-6 parts by weight of monomers are used.

If the amount of the rubbery polymer is less than 5 parts by weight, the impact resistance of the resulting polymer will be poor, which is not preferable. On the other hand, if the amount exceeds 4 parts by weight, the processability and heat resistance of the obtained polymer will be poor, which is not preferable. The monomers are composed of 65-80% by weight of Q-alkylstyrene, 20-35% by weight of vinyl cyanide and 0-11% by weight of styrene.

If the Q-alkylstyrene content is less than 65% by weight, the resulting polymer will have poor heat resistance.

On the other hand, if it exceeds 8% by weight, unreacted monomers will increase at the end of polymerization, which is not preferable. Vinyl cyanide 2% by weight
If it is less than 20%, there will be a large amount of unreacted monomer at the end of polymerization.

Moreover, if it exceeds 35% by weight, the heat resistance of the obtained polymer will be poor, which is not preferable. If the amount of styrene exceeds 1% by weight, the resulting polymer will have poor heat resistance, which is not preferred.

In view of the heat resistance of unreacted monomers and polymers, Q-alkylstyrene 70-7% by weight, vinyl cyanide 21-2
Particularly preferred are % insects and 1-8% styrene by weight.

In the present invention, first, the entire amount of Q-alkylstyrene and the vinyl cyanide moiety are subjected to polymerization, and the polymerization is continued until the generation of new polymerization heat stops.

In the polymerization tank, a polymer having a very high content of Q-alkylstyrene is produced, and unreacted single stars mainly composed of Q-alkylstyrene remain. The amount of vinyl cyanide used is particularly preferably 10-95% by weight of the total amount of vinyl cyanide.

There is no particular restriction on the method of adding these monomers in the polymerization of the total amount of Q-alkylstyrene and the vinyl cyanide moiety, and a batch addition method, a continuous addition method, etc. can be used. Q
- Do not polymerize the entire amount of alkyl styrene and the vinyl cyanide portion, and add a portion of the Q-alkyl styrene together with a rubbery polymer etc. that will be added later, or use the entire amount of vinyl cyanide instead of the vinyl cyanide portion. This makes it difficult to suppress unreacted monomers at the end of polymerization.

After polymerizing the entire amount of Q-alkyl styrene and the cyanide pinylene portion until the generation of new polymerization heat stops, the rubbery polymer, the remaining vinyl cyanide, and styrene are added, and polymerization is performed.

There are no particular restrictions on the method of adding the rubbery polymer and these monomers, and a batch addition method, continuous addition method, etc. can be used.

If the rubbery polymer and styrene are added during the polymerization of the entire amount of Q-alkyl styrene and the vinyl cyanide moiety, it will be difficult to suppress unreacted monomers at the end of the polymerization.

Incidentally, during the polymerization, a polymerization degree regulator such as a chain transfer agent may be used if necessary.

A known method can be used to obtain a resin from the polymer latex thus obtained.

That is, a powder is obtained by performing salting using a salting-out agent such as magnesium sulfate. This powder is kneaded with a Banbury mixer or rolls and used for molding. At this time, if necessary, commonly used processing aids such as stabilizers and plasticizers and pigments may be added. EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these in any way.

Example 1 In a reactor purged with nitrogen, 140 parts by weight of deionized water and 2.0 parts by weight of sodium lauryl sulfate were added. parts by weight, potassium persulfate 0.
After adding 5 parts by weight and 0.0 parts by weight of n-dodecyl mercaptan and heating at 70:00, 7% by weight of the total amount of Q-methylstyrene and the total amount of acrylonitrile was added,
Start polymerization.

Polymerization heat was removed by cooling water flowing through the outer wall of the reactor, and polymerization was carried out while maintaining the inside of the reaction system at 70°C. After the generation of new polymerization heat has stopped, the total amount of polybutadiene latex, the total amount of styrene, and the remainder of acrylonitrile (30% by weight of the total amount) are added while maintaining the inside of the reaction system at 7,000 ℃.
was added, and the polymerization was continued at 70 oo while the heat of polymerization was removed by cooling water flowing through the outer wall of the reactor. The monomer composition ratio is as follows. 1 parts by weight of polybutadiene latex 1 (solid content) 2 parts by weight of monomer 9・Q-methylstyreso 72% by weight・acrylonitrile
26% by weight - Styrene 2% by weight Table 1 shows the unreacted monomers at the end of polymerization and the physical properties of the obtained polymer.

Example 2 Polymerization was carried out in the same machine as in Example 11, except that the monomer composition ratio was changed as follows.

1 parts by weight of polybutadiene latex 2 parts by weight of monomer 9・Q
-Methylstyrene 75% by weight, acrylonitrile 25% by weight, styrene
Table 1 shows the unreacted monomer and the physical properties of the obtained polymer at the end of 0% polymerization.

Example 3 Polymerization was carried out in the same manner as in Example 11, except that the monomer composition ratio was changed as shown below, and the amount of acrylonitrile used relative to the total amount of Q-methylstyrene was changed to 8% cloudiness of the total acrylonitrile. .

1 Polyptadiene latex 15 parts by weight (solid content) 2 Monomers 85 parts by weight ・Q-methylstyrene 75% by weight ・Acrylonitrile 22% by weight ・Styrene 3% by weight Reacted monomers at the end of polymerization and the obtained Table 1 shows the physical properties of the polymer.

Example 4 Polymerization was carried out in the same manner as in Example-1, except that the monomer composition ratio was changed as shown below, and the amount of acrylonitrile used relative to the total amount of Q-methylstyrene was changed to 55% by weight of the total acrylonitrile. Ta.

1 parts by weight of polybutadiene latex 3 (solid content) 2 parts by weight of monomer 7・Q-methylstyrene 65% by weight・acrylonitrile
20% by weight - Styrene 8% by weight Table 1 shows the physical properties of the reacted monomer and the obtained polymer at the end of polymerization.

Comparative Example 1 In the same composition ratio as in Example-3, the entire amount of Q-methylstyrene and the entire amount of acrylonitrile were added and polymerization was performed.

Thereafter, the entire amount of polybutadiene latex and the entire amount of styrene were added to continue polymerization. Table 1 shows the unreacted monomer at the end of polymerization and the physical properties of the obtained polymer. Comparative Example 2 In the same composition ratio as in Example-3, after polymerization was carried out at 5% by weight of the total Q-methylstyrene and 45% by weight of the total acrylonitrile, the total amount of polybutadiene, the balance of Q-methylstyrene, and the acrylonitrile were The remaining amount and the entire amount of styrene were added to continue polymerization.

Table 1 shows the unreacted monomer at the end of polymerization and the physical properties of the obtained polymer.

Table-1 *ASTM D-648 *2ASTM D-256 1/4″, 20℃ *3 High/lower flow tester 230℃, 60K tie

Claims (1)

[Claims] 1 5-40 parts by weight of a rubbery polymer, 95-95% of monomers consisting of 65-80% by weight of α-alkylstyrene, 20-35% by weight of vinyl cyanide and 0-10% by weight of styrene.
In the method of emulsion polymerization of 60 parts by weight using a radical initiator, the entire amount of α-alkylstyrene and part of the vinyl cyanide are polymerized, and then the rubbery polymer and the remaining vinyl cyanide and styrene are added. and polymerization.