JPH07138318A - Production of copolymer - Google Patents

Abstract

PURPOSE:To obtain a copolymer having low yellowness and excellent in transparency, heat resistance and mechanical strength by heating an amide formed from a maleic anhydride copolymer in the presence of a specified stabilizing agent to effect ring closure to thereby form an imide. CONSTITUTION:In producing a copolymer containing succinimide units of the formula by the reaction of a maleic anhydride copolymer having a relative solution viscosity of 0.1-10.0 and consisting of 40-60mol% maleic anhydride units, 60-40mol% olefin units and 0-20mol% copolymerizable other monomer units with at least one amine compound, an amide formed from the maleic anhydride copolymer is heated in the presence of at least one stabilizer selected from a phosphorus-containing stabilizer, a phenol-base stabilizer, a sulfur- containing stabilizer and an amine-base stabilizer to effect ring closure to thereby form an imide. The obtained copolymer can be used for many applications, e.g. various optical parts outomotive parts and electrical and electronic parts.

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. The copolymer obtained by the method of the present invention can be used for various optical parts and automobiles. It can be used for many applications such as parts and electric / electronic parts.

[0002]

2. Description of the Related Art Recently, plasticization of optical parts such as optical lenses and optical fibers, or automobile parts such as headlight lenses and sunroofs has been actively studied from the viewpoints of productivity and weight reduction. Requirements are becoming more and more stringent.
In particular, there are very strong demands for improving heat resistance.

Copolymers containing succinimide units are
Since it has high heat resistance, various studies have been made since ancient times. For example, a method of copolymerizing N-aromatic substituted maleimide with methyl methacrylate is disclosed in JP-B-43-9753, JP-A-61-141715, and JP-A-61-1.
According to JP-A-71708 and JP-A-62-109811, a method of copolymerizing an N-aromatic substituted maleimide with a styrene-based resin is JP-A-47-6891, JP-A-61-76512 and JP-A-61-76512. 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 processability, and coloration.

Copolymers composed of succinimide units and olefin units are plastics having excellent heat resistance and mechanical properties. British Patent No. 815821 describes a method for producing a succinimide copolymer by reacting a copolymer of maleic anhydride and an olefin with methylamine, wherein the maleic anhydride copolymer is treated with methylamine in benzene. After being amidated with, the solvent was removed, and a light yellow resin was obtained by heating and imidizing in an oven. It has been shown that the color tone is improved by removing the residual maleic anhydride and reacting in an inert atmosphere. In addition, Journal of Pol
ymer Science Part CNo. 16
p. 387 (1967), the imidization reaction of a maleic anhydride copolymer and an alkylamine is described in acetic acid or benzene. However, although the yellow coloration of the copolymer obtained by the above-mentioned method is slightly improved, the requirement as a transparent plastic was not sufficiently satisfied.

[0005]

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.

[0006]

Means for Solving the Problems As a result of intensive studies made by the present inventors in view of this problem, a method for producing a copolymer containing a succinimide unit by reacting a maleic anhydride / olefin copolymer with an amine compound. In the above, it was found that a production method characterized by ring-closing imidization of an amidation product of a maleic anhydride / olefin copolymer in the presence of a certain stabilizer satisfies the above-mentioned object, and completes the present invention. Came to.

That is, the present invention has a relative solution viscosity of 0.1.
Maleic anhydride copolymer consisting of 40 to 60 mol% of maleic anhydride unit, 60 to 40 mol% of olefin unit, and 0 to 20 mol% of other copolymerizable monomer unit of 1 to 10.0. In producing a copolymer containing a succinimide unit represented by the general formula (I) by reacting with more than one kind of amine compound, an amidation product of a maleic anhydride copolymer is used as a phosphorus-based stabilizer, a phenol-based stabilizer, and a thiol. A method for producing a copolymer having low yellowness and excellent transparency, which comprises performing ring-closure imidization by heating in the presence of one or more kinds of stabilizers selected from a system stabilizer and an amine stabilizer. is there.

[0008]

[Chemical 2]

(Here, R ¹ is a hydrogen atom and has 1 to 6 carbon atoms.
The present invention will be described in detail below.

The maleic anhydride copolymer used in the present invention can be easily obtained by radical copolymerization with maleic anhydride, olefins and optionally other copolymerizable monomers.

The olefins used here are 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-methyl-2-pentene, 2-methyl-2-hexene, etc. Of these, olefins, of which isobutene is preferably used in terms of heat resistance and mechanical properties. Further, these olefins can be used alone or in combination of two or more.

In addition, other monomers that can be copolymerized may be copolymerized within the range not impairing the object of the present invention.
As the copolymerizable component, styrene derivatives such as styrene, α-methylstyrene and methylstyrene, dienes such as 1,3-butadiene and isoprene, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate,
Examples thereof include acrylic acid esters such as methyl acrylate and ethyl acrylate, and vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. These can be used alone or in combination of two or more.

The method for obtaining the maleic anhydride copolymer used in the present invention is not particularly limited, but from the viewpoint of reducing the residual maleic anhydride which affects coloring, the monomers are soluble but the product copolymer It is preferable to employ a radical precipitation polymerization method in which the produced copolymer is taken out in the form of particles using a solvent that is insoluble in the combination. Examples of the polymerization solvent in this precipitation polymerization method include known precipitation polymerization solvents, for example, acetic acid esters such as ethyl acetate, propyl acetate and butyl acetate, or mixed solvents of acetic acid ester and alcohol.

The polymerization initiator used for obtaining the above-mentioned maleic anhydride copolymer is benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di (t-butyl) peroxide, Organic peroxides such as t-butylcumyl peroxide, dicumyl peroxide, t-butylperoxyacetate, t-butylperoxybenzoate, perbutylneodecanate or 2,2'-azobis (2,4-dimethyl) Valeronitrile), 2,2′-azobis (2-butyronitrile),
2,2'-azobisisobutyronitrile, dimethyl-
Examples of the azo initiator include 2,2'-azobisisobutyrate and 1,1'-azobis (cyclohexane-1-carbonitrile).

The polymerization temperature can be appropriately set according to the decomposition temperature of the initiator, but generally 40 to 15
It is preferably carried out in the range of 0 ° C.

The content of the maleic anhydride unit in the maleic anhydride copolymer used in the present invention is 40 to 60 mol% of the whole polymer, and the olefin unit in the copolymer is 60 to 40 mol%. And the content of other copolymerizable units in the copolymer is 0 to 20 of the total polymer.
Mol%, preferably 0 to 5 mol%, particularly preferably 0 to 1 mol%.

Since the residual maleic anhydride monomer in the maleic anhydride copolymer affects the coloration during imidization as described above, it is preferable to carry out the above polymerization under the condition of excess olefins. The maleic anhydride / olefin molar ratio in the polymerization is preferably 1 or less. It is also possible to remove the residual maleic anhydride monomer by washing the produced polymer particles after polymerization with a solvent that dissolves maleic anhydride but does not dissolve the copolymer. The residual maleic anhydride monomer content in the maleic anhydride copolymer is 1% by weight or less, particularly 0.1% by weight or less.
It is preferable to set the content to be not more than weight%. Further, it is possible to use a dispersion stabilizer such as a cellulose type or a vinyl alcohol type in these polymerizations.

The relative solution viscosity of the maleic anhydride copolymer used in the present invention is measured by an Ubbelohde viscometer to measure the flow time (t1) of a 0.5 g / dl solution of the maleic anhydride copolymer in N, N-dimethylformamide. ) And the flow time (t0) of N, N-dimethylformamide measured at 23 ° C. are t1 / t0 values. The maleic anhydride copolymer used in the present invention has a relative solution viscosity of 0.1 to 10.0, preferably 0.5 to 5.0. If the intrinsic viscosity is higher than 10.0, the copolymer obtained will have poor moldability, and if it is lower than 0.1, the copolymer obtained will tend to be brittle, which is not preferable.

The amine compound used in the production method of the present invention includes methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, s.
-Butylamine, t-butylamine, cyclohexylamine, and other alkylamines having 1 to 6 carbon atoms, and compounds that easily generate amines by treatment such as heating with ammonia or dimethylurea, diethylurea, and the like. Used. Of these, use of methylamine, ethylamine, isopropylamine, and cyclohexylamine is particularly preferable because the heat resistance of the resulting copolymer can be significantly improved.

The present invention includes a step of reacting the above-mentioned maleic anhydride copolymer with the above amine compound in the presence or absence of a solvent to obtain an amidated product of the maleic anhydride copolymer. At this time, the reaction temperature is not particularly limited, but is usually in the range of 0 to 150 ° C. The solvent used here is also not particularly limited, but aromatic solvents such as benzene, toluene and xylene, alcohol solvents such as methanol, ethanol, propanol and butanol, ketone solvents such as acetone and methyl ethyl ketone, and methyl acetate. , Ethyl acetate, propyl acetate,
Examples include acetic acid esters such as butyl acetate, N, N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, water and mixed solvents thereof. When a solvent is used, a maleic anhydride copolymer is used. An amidated product can be synthesized by dissolving or dispersing in a solvent and adding an amine compound.

In the present invention, a copolymer containing a succinimide unit represented by the general formula (I) is obtained by heating an amidated product of the above maleic anhydride copolymer in the presence of a stabilizer to effect ring-closure imidization. It is a thing. Here, the amidated product of the maleic anhydride copolymer in this step can be used as a polymer particle, a polymer solution or a dispersion solution, etc., but from the viewpoint of economic efficiency such as simplification of the step and productivity, a solvent is used. It is preferable to use no solvent or in the presence of a small amount of solvent such as 10 parts by weight or less based on 100 parts by weight of the amidated product of the maleic anhydride copolymer.

The imidization temperature is 100 to 400 ° C.
Preferably 120 to 350 ° C, particularly preferably 140 to
When the reaction temperature is 320 ° C. and the reaction temperature is less than 100 ° C., the imidization reaction is difficult to proceed, and when it exceeds 400 ° C., the resulting copolymer may be colored due to thermal deterioration. Further, the reaction temperature can be raised or lowered continuously or stepwise. Further, various basic or acidic catalysts such as triethylamine and toluenesulfonic acid may be added as a reaction catalyst. Also,
The imidization ratio in the imidization is affected by the reaction temperature, the reaction time, etc., but in order to obtain a copolymer having sufficient heat resistance, the maleic anhydride unit contained in the copolymer is used. On the basis, it is preferable that 80 mol% or more, preferably 95 mol% or more, and particularly 99 mol% or more thereof are converted into succinimide units. If the reaction rate is less than 80 mol%, the thermal stability of the resulting copolymer may be deteriorated.

The stabilizer used in the production method of the present invention is
One or more compounds selected from phosphorus-based stabilizers, phenol-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers. Examples of phosphorus-based stabilizers include triphenyl phosphite, tris (2,4-di ( t-butyl) phenyl) phosphite, tris (nonylphenyl) phosphite, cyclic neopentanetetrayl-bis (octadecylphosphite), 4,4'-butylidene-bis (3-methyl-6- (t-butyl) ) Phenyl-di
(Tridecyl)) Phosphite, Tetrakis (2,4)
-Di (t-butyl) phenyl) -4,4'-biphenylene phosphite and the like. Further, as a phenolic stabilizer, triethylene glycol-bis [3
-(3- (t-butyl) -5-methyl-4-hydroxyphenyl) propionate], 1,3-hexanediol-bis [3- (3,5-di (t-butyl) -4-hydroxyphenyl) Propionate], pentaerythrityl-tetrakis [3- (3,5-di (t-butyl) -4]
-Hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di (t-butyl)]
-4-Hydroxyphenyl) propionate], octadecyl-3- (3,5-di (t-butyl) -4-hydroxyphenyl) propionate, 2,2-thiobis (4
Methyl-6- (t-butyl) phenol), N, N'-
Hexamethylenebis (3,5-di (t-butyl) -4-
Hydroxynnamamide), 3,5-di (t-butyl)-
4-hydroxy-benzylphosphonate-diethyl ester and the like can be mentioned. Furthermore, examples of the sulfur-based stabilizer include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and examples of the amine-based stabilizer include 2-
Bis (1,2,2,2,2,5-di (t-butyl) -4-hydroxybenzyl) -2- (n-butyl) malonate
6,6-pentamethyl-4-piperidyl), bis (2,2
2,6,6-tetramethyl-4-piperidinyl) sebacate and the like can be mentioned. Further, two or more kinds of these stabilizers may be used in combination. Of these, a phosphorus stabilizer or a combination system of a phosphorus stabilizer and a phenolic stabilizer is particularly preferable, and when a combination system of a phosphorus stabilizer and a phenolic stabilizer is used, a phosphorus stabilizer / phenolic stabilizer is used. The weight ratio of the agents is 100/0 to 5/95, especially 90/10 to 50
It is preferably in the range of / 50.

The amount of these stabilizers added is 0.00 based on 100 parts by weight of the amidated maleic anhydride copolymer.
5 to 5 parts by weight, preferably 0.01 to 1 part by weight, particularly preferably 0.05 to 0.5 part by weight. This addition amount is 0.
If it is less than 005 parts by weight, the effect of improving the yellowness may be low, and if it exceeds 5 parts by weight, it is not economical.

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

Particularly, from the viewpoint of improving the color tone and economical efficiency,
It is preferable to use an extruder equipped with a deaerator, and a mixture of an amidation product of maleic anhydride copolymer particles and a stabilizer is heated and melted using an extruder equipped with a deaerator, and water and excess amine produced by the reaction are used. It is preferable to perform ring-closing imidization while removing the above.

If necessary, a heat stabilizer, an ultraviolet stabilizer, various lubricants, dyes, antistatic agents, various plastics, elastomers, etc. may be added to the copolymer obtained by the production method of the present invention. You may.

The resin obtained by the production method of the present invention is
It has excellent color and transparency and is useful in a wide range of applications such as various optical parts, automobile parts, electric / electronic parts, medical food parts, etc.
Further, a product having an excellent color tone can be obtained even when compounded with various plastics or elastomers.

[0029]

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

The polymer produced in this example was confirmed by elemental analysis, IR measurement and NMR measurement. The relative solution viscosity of the obtained polymer is N, N
Measured at 23 ° C. using an Ubbelohde viscometer with dimethylformamide (DMF) as the solvent.

Further, the yellowness of the obtained polymer is J
According to IS K5401, a 0.8 mm pressed test piece was used for evaluation with a color computer (Suga Test Instruments Co., Ltd.) (reflection method; tristimulus value x: 79.44 of reflector,
y: 82.22, z: 94.51).

Reference Example 1 Synthesis of Maleic Anhydride / Isobutene Copolymer A maleic anhydride (2.8 kg), lauryl mercaptan (10 g) was added to a 30-liter autoclave equipped with a stirrer, nitrogen inlet pipe, isobutene inlet pipe, thermometer and degassing pipe. After charging 6.3 g of t-butyl peroxypivalate and 19 l of isopropyl acetate and purging with nitrogen several times, 5.2 l of liquefied isobutene was charged and the reaction was carried out at 60 ° C. for 6 hours.

The obtained particles are centrifuged and dried, and then 4.4
kg of maleic anhydride / isobutene copolymer was obtained. From the elemental analysis, the obtained copolymer contained 50 mol% of maleic anhydride unit. The relative solution viscosity is 2.0
Met. Several batch reactions were carried out by the same method to prepare a maleic anhydride copolymer sample.

Example 1 30 equipped with a stirrer, nitrogen inlet tube, thermometer and degassing tube
2 kg of the copolymer particles obtained in Reference Example 1 and 20 l of toluene were charged into an 1-liter autoclave, 750 ml of liquefied methylamine was introduced, and the mixture was stirred at 60 ° C. for 6 hours. The polymer particles after the reaction were centrifuged and dried to obtain 2.4 kg of an amidated product of a maleic anhydride / isobutene copolymer.

The obtained copolymer was analyzed by IR to find 18
The disappearance of the absorption due to the acid anhydride at 50 cm ⁻¹ and the new absorption due to the amide and carboxylic acid units confirmed that the acid anhydride unit was ring-opened amidated with the amine. 0.1 parts by weight of tris (2,4-di (t-butyl) phenyl) phosphite was shaken into the amidated product of the maleic anhydride / isobutene copolymer particles, and the mixture was shaken from the bottom of the hopper in the direction of the tip nozzle to 150
C., 260.degree. C., 280.degree. C., and 270.degree. C. are continuously extruded under a nitrogen atmosphere using a twin-screw extruder and extruded while removing water, excess amine, etc. produced by the reaction with a vent, and a transparent strand. Got The obtained strand was cut to obtain a transparent pellet.

From the elemental analysis, IR measurement and ¹³ C-NMR measurement, it was confirmed that the obtained copolymer was a copolymer composed of 50 mol% of N-methylsuccinimide unit and 50 mol% of isobutene unit. The yellow degree of the obtained polymer was 4.5. The obtained pellets were injection-molded using a mini mat (manufactured by Sumitomo Heavy Industries, Ltd.) at an injection temperature of 300 ° C and a mold temperature of 120 ° C to prepare test pieces. Bending strength of the obtained specimen is 1300 kg / cm ^2, the flexural modulus 46000kg / cm ^2, heat distortion temperature 145
It was ℃.

Example 2 By the same operation as in Example 1, 0.15 part by weight of pentaerythrityl-tetrakis [3- (3,5) was used as a stabilizer.
-Di (t-butyl) -4-hydroxyphenyl) propionate] was used to extrude the copolymer. The yellowness of the obtained polymer was 6.7.

Example 3 By the same operation as in Example 1, 0.1 part by weight of bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate was added as a stabilizer to prepare a copolymer. Extruded. The yellow degree of the obtained polymer was 6.5.

Example 4 By the same operation as in Example 1, 0.1 part by weight of tris (2,4-di (t-butyl) phenyl) phosphite as a stabilizer and 0.05 part by weight of pentaerythrityl were used. -Tetrakis [3- (3,5-di (t-butyl) -4-]
Hydroxyphenyl) propionate] was added to extrude the copolymer. The yellow degree of the obtained polymer was 4.2.

Comparative Example 1 By the same operation as in Example 1, a copolymer was extruded without adding a stabilizer. The yellowness of the obtained polymer was 10.8.

[0041]

As described above, according to the production method of the present invention, it is possible to obtain a succinimide unit-containing copolymer having low yellowness and excellent transparency.
It is useful in many fields including automobile parts and electric / electronic parts.

Claims (1)

[Claims] 1. A maleic anhydride unit having a relative solution viscosity of 0.1 to 10.0, 40 to 60 mol%, and an olefin unit, 6.
0-40 mol% and other copolymerizable monomer units 0-
In producing a copolymer containing a succinimide unit represented by the general formula (I) by reacting 20 mol% of a maleic anhydride copolymer with one or more amine compounds, a maleic anhydride copolymer of The amidated compound in the presence of one or more stabilizers selected from phosphorus-based stabilizers, phenol-based stabilizers, sulfur-based stabilizers and amine-based stabilizers,
A method for producing a copolymer, which comprises ring-closing imidization by heating. [Chemical 1] (Here, R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group)