JPH072954A - Production of graft copolymer - Google Patents

Abstract

PURPOSE:To obtain a graft copolymer being nontoxic and odorless and having a high graft efficiency by polymerizing a vinyl monomer in the presence of a specified addition cleavage type chain transfer agent and further grafting a vinyl monomer of a different composition onto the obtained polymer. CONSTITUTION:A process for producing a graft copolymer by polymerizing a vinyl monomer or its mixture in the presence of an addition cleavage type chain transfer agent and a radical polymerization initiator and grafting a vinyl monomer or its mixture of a composition different from that of the above vinyl monomer onto the obtained polymer, which process comprises using 2,4- diphenyl-4-methyl-1-pentene as the addition cleavage type chain transfer agent, is provided. By using the above addition cleavage type chain transfer agent, a graft copolymer being nontoxic and odorless, having a high graft efficiency and good mechanical properties can be produced efficiently. According to this process, the molecular weight of the branch polymer and the molecular weight of the trunk polymer can be freely controlled, and therefore the properties, such as mechanical strengths, of the obtained copolymer can be adapted for its use.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a graft copolymer. Graft copolymers are used in a wide range of applications such as molding polymers, polymer blend compatibilizers, surface modifiers, paints, adhesives, and non-aqueous dispersants.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a graft copolymer, a method of copolymerizing a polymer having a double bond at a terminal and a vinyl monomer has been used. For example, Japanese Patent Laid-Open No. 1-24
No. 5001 discloses that a vinyl monomer is polymerized with a functional azo initiator in the presence of a collapsible chain transfer agent such as diethyl allyl malonate to synthesize a polymer having a functional group at the terminal, and then the functional group is used. A method is disclosed in which a terminal vinyl polymer is synthesized by reacting a compound that can react with and has a double bond in the molecule, and then copolymerized with another vinyl monomer.
In addition, Progress in Pacific Polymer Science (Progress in Pacific Po)
lymer Science), 1991, 77-8
On page 8, styrene is polymerized in the presence of α- (t-butylthiomethyl) styrene and a radical polymerization initiator,
Then a method of copolymerizing with ethyl acrylate is described. Further, it is generally known that a polymer having a double bond at the terminal can be obtained by polymerizing a vinyl monomer in the presence of an addition cleavage type chain transfer agent. Examples of such addition cleavage type chain transfer agents include α-
Bromomethylstyrene, α-phenoxymethylstyrene, α-alkylthiomethylstyrene, α-t-butylperoxymethylstyrene, α-benzyloxystyrene, methyl-α-phenoxymethyl acrylate, methyl-α-alkylthiomethyl acrylate, methyl-α
-T-butylperoxymethyl acrylate, methyl-
α-Benzyloxyacrylate, α-bromomethylacrylonitrile and the like are known.

[0003]

However, each of the above-mentioned methods for producing a graft copolymer has the following problems. That is, JP-A-1-245001
In the method of the publication, the production of a polymer having a double bond at the end is complicated in two steps, and the polymer having a functional group at the end is reacted with a compound having a double bond at a relatively low level. There is a problem that only a polymer having a molecular weight can be handled. Further, among the conventional methods of using an addition-cleavage type chain transfer agent, the method of using a compound containing bromine or sulfur has the problems of environmental pollution such as odor, coloring and toxicity, and t-butylperoxy group, The method using a compound containing a phenoxy group, a benzyl group and the like has problems such as low graft efficiency of the obtained graft copolymer and low mechanical strength. Further, the above-mentioned addition-cleavage type chain transfer agent is manufactured by a multi-step synthetic process. Further, there is a problem in that a practical manufacturing method has not been established and the cost is high. Therefore, there is a demand for a method for producing a graft copolymer which is inexpensive, has no problems of odor, toxicity, coloring, etc., and has a high graft efficiency and a high mechanical strength of the obtained graft copolymer.

[0004]

DISCLOSURE OF THE INVENTION As a result of a long-term study of the problems of the above conventional method, the present inventors have found that 2,4-diphenyl-4-methyl-
It was confirmed that the above problems were solved by using 1-pentene, and the present invention was completed. That is, the present invention is to polymerize a vinyl monomer alone or a vinyl monomer mixture in the presence of an addition cleavage type chain transfer agent and a radical polymerization initiator, and then to the obtained polymer, the vinyl monomer In the method for producing a graft copolymer by polymerizing a vinyl monomer or a mixture of vinyl monomers having a composition different from that of the polymer, 2,4-diphenyl-4-methyl-1-pentene is used as an addition cleavage type chain transfer agent. It relates to a method for producing a graft copolymer, which is characterized by being used.

Specific examples of the vinyl monomer used for the polymerization of the branch polymer of the graft copolymer in the present invention include styrene; α-methylstyrene; acrylonitrile; vinyl acetate; methacrylic acid and methylmethacrylate, butyl. Methacrylates such as methacrylate and 2-hydroxyethyl methacrylate; acrylates such as acrylic acid and methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate; fumaric acid and fumaric acid esters; maleic acid and maleic acid esters; itaconic acid and Itaconic acid esters; N-alkylmaleimides and the like can be mentioned. It is also possible to use a mixture of these vinyl monomers. The vinyl monomer used for the polymerization of the trunk polymer of the graft copolymer is selected from the same vinyl monomers as described above, but the type of vinyl monomer used for the branch polymer and the trunk polymer or their blending The ratio is usually different.
The ratio of the branch polymer to the trunk polymer can be arbitrarily changed, but it is usually used in a polymerization ratio of 1:20 to 20: 1, preferably 1: 5 to 5: 1. Outside of these ranges, the performance as a graft polymer is similar to a homopolymer or a random polymer, and the characteristics as a graft polymer are not clearly shown.

In the present invention, 2,4-diphenyl-4-methyl-1- used as an addition cleavage type chain transfer agent
Penten (hereinafter abbreviated as MSD) is known as a general polymerization control agent for vinyl monomers, and is industrially produced by acid-catalyzed dimerization of α-methylstyrene. In the present invention, MSD is used in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of all vinyl monomers used for polymerization. If it is less than 0.05 parts by weight, the grafting efficiency will be low, and if it is used in excess of 5 parts by weight, the molecular weight of the polymer produced will be low and the mechanical strength will be low, which is not preferable.

In the present invention, the polymerization is carried out by thermal polymerization or in the presence of a polymerization initiator. As the polymerization initiator, a commonly used polymerization initiator is used. For example,
-Butyl peroxide; dialkyl peroxides such as dicumyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane; 2,2
-Peroxyketals such as di-t-butylperoxybutane, t-butylperoxybenzoate; t-hexylperoxyisopropyl carbonate; t-butylperoxy-2-ethylhexanoate; peroxyesters such as t-butylperoxyacetate, Methyl ethyl ketone peroxide; ketone peroxides such as cyclohexanone peroxide; cumene hydroperoxide; t-butyl hydroperoxide; hydroperoxides such as paramenthane hydroperoxide; benzoyl peroxide; dialkyl peroxides such as lauroyl peroxide; peroxydicarbonates such as isopropyl peroxydicarbonate. , Ammonium persulfate;
Potassium persulfate; persulfate such as sodium persulfate, 2,2-
Azo compounds such as azobisisobutyronitrile and 2,2-azobisisovaleronitrile can be used. The polymerization initiator is used in an amount of 0 to 2 parts by weight based on 100 parts by weight of the vinyl monomer used. When the amount of the polymerization initiator used exceeds 2 parts by weight, it becomes difficult to control the polymerization rate.

In the present invention, a chain transfer agent generally used for the polymerization of vinyl monomers may be used together. Particularly in the latter half of the polymerization, the molecular weight of the trunk polymer can be adjusted by adding a chain transfer agent. Examples of chain transfer agents that can be used include mercaptans such as N-dodecyl mercaptan and 2-ethylhexyl-β-mercaptopropionate, and terpenes such as terpinolene.

The polymerization temperature used in the present invention varies depending on the kind of the polymerization initiator, but is in the range of 30 to 200 ° C. If the temperature is lower than 30 ° C, the polymerization rate becomes slow, and if the temperature exceeds 200 ° C, the polymerization rate becomes too fast, which makes it difficult to control. Further, different temperatures can be used in the first half and the second half of the polymerization, and the polymerization can be carried out while gradually changing the temperature. Particularly, the polymerization temperature in the first half of the polymerization is preferably 60 ° C or higher. If it is less than 60 ° C, the grafting efficiency tends to decrease.

The polymerization method used in the present invention includes, for example, suspension polymerization, solution polymerization, bulk polymerization and the like, and it is also possible to use them in combination. The vinyl monomer and MSD can be added either temporarily or continuously. When two or more vinyl monomers are used in the first half or the second half of the polymerization, the polymerization can be carried out while changing the addition amount and composition of the vinyl monomer in order to adjust the copolymerization ratio.

[0011]

INDUSTRIAL APPLICABILITY The method for producing a graft copolymer of the present invention uses MSD as an addition-cleavage type chain transfer agent to obtain a graft copolymer having no toxicity and odor, high graft efficiency and good mechanical properties. It can be manufactured efficiently. Further, according to the method of the present invention, since the molecular weights of the branch polymer and the trunk polymer can be freely adjusted within a wide range, the mechanical strength and other physical properties of the obtained graft copolymer can be adjusted according to its use. . In addition, the MSD used in the present invention is easier to produce than other addition-cleavage chain transfer agents, and is economically advantageous.

[0012]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In these examples, the abbreviations of the organic peroxide as the polymerization initiator and the vinyl monomer used for the polymerization are as follows. MSD: 2,4-diphenyl-4-methyl-1-pentene (trade name: NOFMER MSD, manufactured by NOF CORPORATION, purity 95%) BTMS: α- (t-butylthiomethyl) styrene BuZ: t-butyl Peroxybenzoate (trade name: Perbutyl Z, manufactured by NOF Corporation, purity 99%) LPO: lauroyl peroxide (trade name: Perloyl L, manufactured by NOF Corporation, purity 99%) Bu3M: 1,1-di-t-butylperoxy-3 ，
3,5-Trimethylcyclohexane (Brand name: Perhexa 3M, manufactured by NOF Corporation, purity 90%) BuO: t-butylperoxy-2-ethylhexanoate (Brand name: Perbutyl O, manufactured by NOF Corporation, purity 96)
%) BuC: t-butyl cumyl peroxide (trade name: Perbutyl C, manufactured by NOF CORPORATION, purity 95%) BuPV: t-butyl peroxypivalate (trade name:
Perbutyl PV, manufactured by NOF CORPORATION, purity 70%) MMA: methyl methacrylate BMA: n-butyl methacrylate ST10: tricalcium phosphate (trade name: Super Tight ST10, manufactured by Nippon Kagaku Kogyo Co., Ltd.) Neulex R: sodium dodecylbenzenesulfonate ( (Made by Nippon Oil & Fat)

Example 1 A stainless steel autoclave having a volume of 5000 ml was charged with S
40 g of T10, 2 g of Neulex R and 2000 ml of deionized water were charged, and then styrene 1000
g, BuZ 0.5 g and MSD 10 g were added. The space in the autoclave was sufficiently replaced with nitrogen gas, and the container was sealed. After that, 1000 rpm. Under stirring at 120 ℃
Polymerization was carried out for 5 hours. After that, cool to 75 ° C and
A 1000g and LPO 2g were added, and superposition | polymerization was performed at 75 degreeC for 5 hours. Then, it was cooled, the polymer was taken out, and washed to obtain 1990 g of a copolymer. Polymerization conversion rate of MMA measured by gas chromatography (GLC) is 99%
Met. The obtained copolymer was almost odorless. The resulting graft copolymer was added to cyclohexane at 100 ° C for 8 hours.
It was 61% as a result of measuring the grafting efficiency (polystyrene which became a graft copolymer × 100 / amount of styrene monomer charged) by immersing for time and extracting polystyrene which was not grafted.

Comparative Example 1 The procedure of Example 1 was repeated except that MSD was not used. As a result, the polymerization conversion rate of MMA was 99%.
Met. The graft efficiency was 6%.

Comparative Example 2 Instead of using 10 g of MSD in Example 1,
It carried out according to Example 1 except that 10 g of BTMS was used. As a result, the polymerization conversion rate of MMA was 99%.
The obtained copolymer had a sulfur odor. The graft efficiency was 58%. From the results of Example 1 and Comparative Examples 1 and 2, it can be seen that the graft copolymer produced by the method of the present invention has high grafting efficiency and has no odor as compared with the case of using a conventionally known chain transfer agent.

Example 2 Using the same reactor as in Example 1, 40 g of ST10, 2 g of Neulex R and 2000 ml of deionized water were charged, and then 1000 g of BMA, 2 g of BuO and M.
2 g of SD was added. After nitrogen replacement, 1000 rpm
Polymerization was carried out at 90 ° C. for 5 hours with stirring. Cool to room temperature, styrene 400g, acrylonitrile 600g
And 0.5 g of BuC were charged. Then at 140 ℃ 5
Polymerization was carried out for a time. Then, it is cooled and washed to obtain a copolymer 198.
5 g was obtained. The polymerization conversion rate of styrene by GLC analysis was 98%. A test piece was prepared from the obtained copolymer by injection molding and the mechanical strength was measured.
It was kg / cm ² and elongation at break 220%.

Comparative Example 3 The procedure of Example 2 was repeated except that the MSD was not used. As a result, the copolymer obtained had a breaking strength of 39 kg / cm ² and a breaking elongation of 180%. From Example 2 and Comparative Example 3, it is understood that the graft copolymer produced by the method of the present invention has improved breaking strength and breaking elongation due to grafting.

Example 3 In a 1000 ml four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, 100 g of methacrylic acid and MSD 2
g, methyl isobutyl ketone 100 g and Bu3M
3 g was charged and reacted at 110 ° C. for 5 hours. Further, 200 g of styrene, 5 g of BuPV and 100 g of methyl isobutyl ketone were added and reacted at 70 ° C. for 5 hours. The polymerization conversion rate of styrene was 97%. The resulting solution was diluted with water to prepare a 20% polymer solution. The obtained aqueous solution was transparent without separation even after 24 hours.

Example 4 The procedure of Example 3 was repeated except that the MSD was not used. As a result, the polymerization conversion rate of styrene was 98.
%Met. The resulting aqueous solution became cloudy and the styrene polymer separated and precipitated within 1 hour. From Example 3 and Comparative Example 4, it can be seen that the graft copolymer produced by the method of the present invention has improved polymer compatibility due to grafting.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mika Yamada 3-36 Kasugacho, Handa City, Aichi Prefecture

Claims (1)

[Claims] 1. A vinyl monomer alone or a vinyl monomer mixture is polymerized in the presence of an addition-fragmentation type chain transfer agent and a radical polymerization initiator, and then the above-mentioned vinyl monomer is added to the resulting polymer. In the method for producing a graft copolymer by polymerizing a vinyl monomer having a composition different from that of vinyl monomer or a mixture of vinyl monomers, 2,4-addition type chain transfer agent is used.
A method for producing a graft copolymer, which comprises using diphenyl-4-methyl-1-pentene.