JP3286860B2 - Method for producing copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copolymer having low yellowness and excellent transparency.

[0002]

2. Description of the Related Art Recently, plastic parts such as optical parts such as optical lenses and optical fibers or automobile parts such as headlight lenses and sunroofs have been actively studied from the viewpoint of productivity and weight reduction. Demands on plastics are becoming more stringent. In particular, there is a very strong demand for improvement in heat resistance.

A copolymer having a succinimide unit is
Various studies have been made since ancient times for having high heat resistance. For example, a method of copolymerizing methyl methacrylate with an N-aromatic substituted maleimide is disclosed in JP-B-43-9753, JP-A-61-141715, and JP-A-61-141715.
JP-A-171708 and JP-A-62-19811 disclose a method of copolymerizing a styrene-based resin with an N-aromatic substituted maleimide, as disclosed in JP-A-47-6891 and JP-A-61-76512. Kaisho 61-2768
No. 07 publication. However, the resin obtained here has better heat resistance as the N-aromatic substituted maleimide content increases, but has problems such as brittleness, poor workability, and coloring.

[0004] A copolymer comprising a succinimide unit and an olefin unit is a plastic having excellent heat resistance and mechanical properties.

[0005] British Patent No. 815,821 describes a method for producing a succinimide copolymer by reacting a copolymer of maleic anhydride and olefins with methylamine. Is amidated with methylamine in benzene, the solvent is removed, and the mixture is heated and imidized in an oven to obtain a pale yellow resin. It is also shown that the color tone is improved by removing the residual maleic anhydride and reacting in an inert atmosphere.

[0006] Furthermore, Journal of Poly
mer Science PartC No16 p3
87 (1967) discusses an imidation reaction between a maleic anhydride copolymer and an alkylamine in acetic acid or benzene.

However, the copolymers obtained by these methods still have high yellowness, and have not been able to sufficiently satisfy the requirements as transparent plastics.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a copolymer having low yellowness and excellent transparency, heat resistance and mechanical strength.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that imide copolymers are formed by the reaction of a copolymer obtained by copolymerizing maleic anhydride and olefins with an alkylamine compound. The present inventors have found that the above object can be achieved by using a specific solvent in a reaction for producing a polymer, and have completed the present invention.

That is, the present invention has a relative solution viscosity of 0.1
A copolymer obtained by copolymerizing 40 to 60 mol% of maleic anhydride, 60 to 40 mol% of olefins, and 0 to 20 mol% of another copolymerizable monomer; In a reaction step of producing a copolymer containing a succinimide unit by reaction with one or more alkylamine compounds of 1 to 6, an alcohol-based solvent is used as a solvent during the amidation reaction and / or the imidation reaction. Is a method for producing a copolymer having low yellowness and excellent transparency. Hereinafter, the present invention will be described in detail.

The copolymer of maleic anhydride and olefin used in the present invention (hereinafter referred to as maleic anhydride copolymer) comprises maleic anhydride, olefins and other copolymerizable maleic anhydrides. It can be easily obtained by radical copolymerization with a monomer. The polymerization method performed here is not particularly limited, but it is preferable to perform polymerization by a so-called precipitation polymerization method from the viewpoint of reducing residual maleic anhydride that affects coloring.

The olefins used in the maleic anhydride copolymer include ethylene, isobutene,
2-methyl-1-butene, 2-methyl-1-pentene,
2-methyl-1-hexene, 1-methyl-1-heptene, 1-isooctene, 2-methyl-1-octene, 2
-Ethyl-1-pentene, 2-methyl-2-butene, 2
Olefins such as -methyl-2-pentene and 2-methyl-2-hexene, and it is preferable to use isobutene from the viewpoint of heat resistance and mechanical properties. These are 1
They can be used alone or in combination of two or more.

Further, other copolymerizable monomers can be copolymerized with the above-mentioned copolymer within a range not to impair the object of the present invention. Examples of the copolymerizable component include styrene derivatives such as styrene, α-methylstyrene, and methylstyrene; dienes such as 1,3-butadiene and isoprene; methacrylates such as methyl methacrylate and ethyl methacrylate; acrylic acid Acrylic esters such as methyl and ethyl acrylate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; and the like can be used alone or in combination of two or more.

Examples of the polymerization solvent for the polymerization of the maleic anhydride copolymer include known precipitation polymerization solvents, for example, acetates such as ethyl acetate, propyl acetate, and butyl acetate, or a mixed solvent of acetate and alcohol.

As the polymerization initiator, benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di (t-butyl)
Organic peroxides such as peroxide, t-butylcumyl peroxide, dicumyl peroxide, t-butylperoxyacetate, t-butylperoxybenzoate, perbutylneodecanate, and 2,2′-azobis (2, 4-dimethylvaleronitrile), 2,2'-azobis (2-butyronitrile), 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 1,1'-azobis (Cyclohexane-1
-Carbonitrile) and the like.

Further, the polymerization temperature can be appropriately set according to the decomposition temperature of the initiator, but is generally 40 to 1
It is preferable to carry out in the range of 50 ° C.

The maleic anhydride unit in the maleic anhydride copolymer used in the present invention is composed of 4 units of the whole polymer.
0 to 60 mol%, the olefin unit is 60 to 40 mol%, and the other copolymerizable units are 0 to 60 mol% of the whole polymer.
20 mol%. Of these, the other copolymerizable unit is preferably from 0 to 5 mol%, more preferably from 0 to 1 mol%.

As described above, since the residual maleic anhydride monomer in the maleic anhydride copolymer affects the coloration at the time of imidization, the polymerization is preferably carried out under an olefin excess condition. The molar ratio of maleic anhydride / olefin used in the copolymerization of the acid copolymer is preferably 1 or less.

Further, the residual maleic anhydride monomer may be removed by washing the polymer particles produced after polymerization with a solvent in which maleic anhydride is dissolved but the copolymer is not dissolved. The amount of the residual monomer in the maleic anhydride copolymer is preferably 1% by weight or less, particularly preferably 0.1% by weight or less.

The maleic anhydride copolymer used in the present invention has a relative solution viscosity of 0.1 to 10.0, especially 0.5 to 10.0.
5.0 is preferred. When the relative solution viscosity exceeds 10.0, the moldability of the obtained imide copolymer deteriorates, and when the relative solution viscosity is less than 0.1, the obtained imide copolymer tends to become brittle, which is not preferable. The relative solution viscosity was determined by measuring the flow time (t1) of a 0.5 g / dl N, N-dimethylformamide solution of maleic anhydride copolymer and the flow time (t0) of N, N-dimethylformamide using an Ubbelohde viscometer. ) Measured at 23 ° C.
Indicates a value.

The carbon number of 1 to 6 used in the production method of the present invention
Examples of the alkylamine compound include methylamine, ethylamine, n-propylamine, isopropylamine,
Primary amines having 1 to 6 carbon atoms, such as n-butylamine, s-butylamine, t-butylamine, cyclohexylamine, and compounds which easily generate amines by treatment such as heating with dimethyl urea, diethyl urea, etc. Amines, ethylamine, isopropylamine and cyclohexylamine are preferred. Also, when the alkylamine has more than 6 carbon atoms, the heat resistance of the obtained copolymer decreases, which is not preferable.

In the reaction for producing an imide copolymer by reacting a maleic anhydride copolymer with an alkylamine compound, an alcoholic solvent is used. Specifically, an alcohol-based solvent such as methanol, ethanol, propanol, butanol or the like is used. To 6 lower aliphatic alcohols,
Particularly, methanol is preferable among them. Further, the alcohol-based solvent used in the present invention also includes a mixed solvent of the above-mentioned alcohols and other solvents. Other solvents include aromatic solvents such as benzene and toluene, and ethers such as dioxane and tetrahydrofuran. The ratio of the alcohol to the other solvent in the mixed solvent is 100: 0 to 5:95 (volume ratio), preferably 1
00: 0 to 10:90, more preferably 100: 0 to
When the ratio is 50:50 and the ratio of the other solvent exceeds 95, the coloring of the imide copolymer obtained may be increased.

The imidation reaction between the maleic anhydride copolymer and the alkylamine compound is a two-stage reaction.
The first reaction is a polymaleamic acid generation reaction by amidation reaction of a maleic anhydride copolymer, and the second reaction is a ring-closing imidation reaction of a polyamic acid. These reactions can be carried out continuously in the same reactor, or, if necessary, a plurality of reactors can be used.

The production method of the present invention is characterized in that an alcoholic solvent is used as a solvent in the above-mentioned first-stage amidation reaction and / or second-stage imidization reaction, and is characterized by a low yellow coloring. The present invention relates to a method for producing a polymer. It is not clear why an imide copolymer having a low yellow coloration can be produced by using an alcohol-based solvent in this way, but the polyamic acid as an intermediate is soluble in the alcohol-based solvent, and is amidated and / or It is considered that the reaction proceeds uniformly and rapidly because the imidation reaction is not hindered, or that by-products are removed together with the solvent.

The amount of the solvent used in the production method of the present invention is 5 parts per 100 parts by weight of the maleic anhydride copolymer.
-2000 parts by weight, particularly preferably 50-200 parts by weight.

When the amount of the solvent is less than 5 parts by weight, the reaction becomes high in viscosity, so that sufficient imidization may be difficult. When the amount of the solvent exceeds 2,000 parts by weight, it is disadvantageous from the viewpoint of productivity. Could be

The reactor used in the production method of the present invention is not particularly limited, and a tank reactor, a tubular reactor, a screw extrusion reactor with a deaerator and the like can be used.

The reaction temperature of the amidation reaction is not particularly limited, but is usually in the range of 0 to 300 ° C.

On the other hand, the imidization reaction temperature is 100 to 400
° C, preferably 120-350 ° C, especially 150-300
C is preferred. When the reaction temperature is lower than 100 ° C., the imidization reaction tends to be difficult to proceed. When the reaction temperature is higher than 400 ° C., problems such as coloring due to thermal degradation may occur.

The reaction temperature can be raised or lowered continuously or stepwise.

Further, triethylamine as a reaction catalyst,
Various basic or acidic catalysts such as toluenesulfonic acid can be added.

The imidation ratio is affected by the supply amount of the alkylamine compound, the reaction temperature, the reaction time, and the like. In order to have sufficient heat resistance, the N-alkyl-substituted succinimide contained in the obtained copolymer is required. It is preferable to appropriately adjust the reaction so that the unit accounts for 30 to 60 mol%, preferably 40 to 60 mol% of the whole polymer.

The resin obtained by the production method of the present invention may contain a heat stabilizer such as a hindered phenol or an organic phosphate, a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer, A lubricant, a dye, an antistatic agent and the like may be added. There is no limitation on the timing of addition, and they can be added after or before imidization.

The resin obtained by the production method of the present invention is
It is excellent in color tone and transparency, and is useful in a wide range of applications such as various optical parts, automobile parts, medical and food fields.

[0035]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

The produced polymer was confirmed by elemental analysis, IR measurement and NMR measurement. The relative solution viscosity of the obtained polymer was determined by N, N-dimethylformamide (DM
F) was measured at 23 ° C. using a Ubbelohde viscometer as a solvent.

The degree of yellowness of the obtained polymer is determined according to JIS K
In accordance with 5401, a 0.8 mm press test piece was used to evaluate with a color computer (Suga Test Instruments Co., Ltd.) (reflection method; tristimulus value of reflector x: 79.44, y: 8).
2.22, z: 94.51). Reference Example 1 Synthesis of maleic anhydride / isobutene copolymer In a 30 l autoclave equipped with a stirrer, a nitrogen inlet tube, an isobutene inlet tube, a thermometer and a degassing tube, 2.8 kg of maleic anhydride, 10 g of lauryl mercaptan, and t-butyl were added. After charging 6.3 g of peroxypivalate and 19 l of isopropyl acetate and purging with nitrogen several times, 5.2 l of liquefied isobutene was charged and reacted at 60 ° C. for 6 hours.

The obtained particles are dried after centrifugation, and then 4.4.
kg of maleic anhydride / isobutene copolymer was obtained. The copolymer obtained by elemental analysis contained 50 mol% of maleic anhydride units. The relative solution viscosity was 2.0. Several batch reactions were performed in the same manner to prepare a maleic anhydride copolymer sample.

Example 1 90 g of the copolymer obtained in Reference Example 1 and 900 ml of methanol were placed in a 2 liter autoclave equipped with a stirrer, a nitrogen inlet tube, an amine inlet tube, a thermometer and a degassing tube.
After nitrogen replacement, 20 g of methylamine was introduced, and
A time reaction was performed. Elemental analysis, IR measurement and ¹³ CN
From the MR measurement, the obtained copolymer was found to contain 50 mol% of N-methylsuccinimide units and 50 mol% of isobutene units.
Was a copolymer consisting of The yellowness of the obtained polymer was 5.1.

Example 2 In the reactor described in Example 1, 90 g of the copolymer obtained in Reference Example 1, 450 ml of methanol and toluene 4
50 ml was charged, and after replacement with nitrogen, 20 g of methylamine was introduced, followed by a reaction at 180 ° C. for 2 hours. Elemental analysis, IR
From the measurement and ¹³ C-NMR measurement, the obtained copolymer was a copolymer composed of 50 mol% of N-methylsuccinimide units and 50 mol% of isobutene units. Also,
The yellowness of the obtained polymer was 5.8.

Comparative Example 1 Into the reactor described in Example 1, 90 g of the copolymer obtained in Reference Example 1 and 900 ml of toluene were charged, and after purging with nitrogen, methylamine was introduced and reacted at 180 ° C. for 2 hours. Was. The yellowness of the obtained polymer was 43.0.

Comparative Example 2 Into the reactor described in Example 1, 90 g of the copolymer obtained in Reference Example 1 and 900 ml of acetic acid were charged, and after purging with nitrogen, methylamine was introduced and reacted at 180 ° C. for 2 hours. Was.
The yellowness of the obtained polymer was 39.0.

[0043]

As is clear from the examples, according to the production method of the present invention, a copolymer having low yellowness and excellent transparency can be obtained. These are useful as optical parts, automobile parts, and electric / electronic parts.

Claims (1)

(57) [Claims] (1) 40 to 60 mol% of maleic anhydride having a relative solution viscosity of 0.1 to 10.0;
0 mol% and 0-20 mol% of other copolymerizable monomers
In the reaction step of producing a copolymer containing a succinimide unit represented by the following general formula (I) by reacting a copolymer obtained by copolymerizing the above with one or more alkylamine compounds having 1 to 6 carbon atoms. A method for producing a copolymer, wherein an alcoholic solvent is used as a solvent during the amidation reaction and / or the imidation reaction. Embedded image (Where R ¹ represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group)