JP3531190B2 - Method for producing copolymer - Google Patents

Description

Description: 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, and is obtained by the method of the present invention. The copolymer can be used for various applications such as various optical parts, automobile parts and electric / electronic parts. 2. Description of the Related Art Recently, plastic parts of optical parts such as optical lenses and optical fibers or automobile parts such as headlight lenses and sunroofs have been actively studied in terms of productivity and weight reduction. Demands for transparent 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 for a long time due to its high heat resistance. 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.
JP-A-71708 and JP-A-62-109811 disclose a method of copolymerizing a styrene resin with an N-aromatic substituted maleimide in JP-A-47-6891, JP-A-61-76512 and JP-A-61-76512. Sho 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] Copolymers comprising 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 consisting of maleic anhydride and olefins with methylamine. Then, the solvent is removed, and the mixture is heated and imidized in an oven to obtain a pale yellow resin. It is shown that the color tone is improved by removing the residual maleic anhydride and reacting in an inert atmosphere. Also, Journal of Pol
ymer Science PartCNo. 16
p. 387 (1967) describes an imidation reaction between a maleic anhydride copolymer and an alkylamine in acetic acid or benzene. However, the copolymer obtained by the above-mentioned method has not been able to sufficiently satisfy the requirements as a transparent plastic, although the yellow coloring is somewhat improved. An object of the present invention is to provide a method for producing a copolymer having a low yellowness and excellent in transparency, heat resistance and mechanical strength. Means for Solving the Problems As a result of intensive studies in view of this problem, the present inventor has obtained a copolymer containing a succinimide unit by reacting a maleic anhydride / isobutene copolymer with an amine compound. The present invention has been found to satisfy the above-mentioned object by a production method characterized in that an amidated maleic anhydride / isobutene copolymer is subjected to ring-closing imidization in the presence of a certain stabilizer. Was completed. That is, the present invention has a relative solution viscosity of 0.1
A maleic anhydride copolymer consisting of 40 to 60 mol% of maleic anhydride units, 60 to 40 mol% of isobutene units and 0 to 20 mol% of other copolymerizable monomer units, In producing a copolymer containing a succinimide unit represented by the general formula (I) by reacting with a plurality of kinds of amine compounds, an amidated maleic anhydride copolymer is converted to a phosphorus-based stabilizer, a phenol-based stabilizer, and a thiol. A method for producing a copolymer having low yellowness and excellent transparency, characterized in that it is subjected to ring-closing imidization by heating in the presence of one or more stabilizers selected from a system stabilizer and an amine stabilizer. is there. [0008] (Where R ¹ is a hydrogen atom, having 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, isobutene and, if necessary, other copolymerizable monomers. In the present invention, isobutene is preferably used from the viewpoint of heat resistance and mechanical properties. In addition, other copolymerizable monomers can be copolymerized within a range not detracting from 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;
Examples include acrylates 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 the coloring, the monomers are soluble, but the copolymerized product is produced. It is preferable to employ a radical precipitation polymerization method in which the resulting copolymer is removed in the form of particles using a solvent in which the coalescence is insoluble. Examples of the polymerization solvent in the precipitation polymerization method 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. The polymerization initiator used to obtain the above-mentioned maleic anhydride copolymer includes 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, and 2,2′-azobis (2,4-dimethyl Valeronitrile), 2,2′-azobis (2-butyronitrile),
2,2'-azobisisobutyronitrile, dimethyl-
Azo initiators such as 2,2′-azobisisobutyrate and 1,1′-azobis (cyclohexane-1-carbonitrile) are exemplified. [0015] The polymerization temperature can be appropriately set according to the decomposition temperature of the initiator.
It is preferable to carry out in a 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 isobutene content in the copolymer is
The content of the other copolymerizable units in the copolymer is from 0 to 20 mol%, and the content of other copolymerizable units in the copolymer is from 0 to 20 mol%.
Mol%, preferably 0 to 5 mol%, particularly preferably 0 to 1 mol%. Further, since the residual maleic anhydride monomer in the maleic anhydride copolymer affects the coloration during imidization as described above, the above polymerization is preferably carried out under an excess of isobutene. In the above, the molar ratio of maleic anhydride / isobutene is preferably 1 or less. The residual maleic anhydride monomer can also 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 maleic anhydride monomer in the maleic anhydride copolymer is preferably 1% by weight or less, particularly preferably 0.1% by weight or less. In these polymerizations, a dispersion stabilizer such as a cellulose-based or vinyl alcohol-based dispersion can be used. The relative solution viscosity of the maleic anhydride copolymer used in the present invention is determined by a Ubbelohde viscometer using a flow time (t1) of a 0.5 g / dl N, N-dimethylformamide solution of the maleic anhydride copolymer. ) And the flow time (t0) of N, N-dimethylformamide measured at 23 ° C. at t1 / t0. The relative solution viscosity of the maleic anhydride copolymer used in the present invention is 0.1 to 10.0, and particularly preferably 0.5 to 5.0. If the intrinsic viscosity is higher than 10.0, the moldability of the obtained copolymer is deteriorated, and if it is lower than 0.1, the obtained copolymer tends 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
Alkylamines having 1 to 6 carbon atoms, such as -butylamine, t-butylamine, and cyclohexylamine; and compounds that readily generate amines upon treatment such as heating of ammonia or dimethylurea, diethylurea, or the like. Used. Of these, methylamine, ethylamine, isopropylamine and cyclohexylamine are particularly preferred, since the heat resistance of the obtained copolymer can be remarkably improved. The present invention includes a step of reacting the above-mentioned maleic anhydride copolymer with the above-mentioned amine compound in the presence or absence of a solvent to obtain an amidated maleic anhydride copolymer. At this time, the reaction temperature is not particularly limited, but is usually in the range of 0 to 150 ° C. There are no particular restrictions on the solvent used here, 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; , Ethyl acetate, propyl acetate,
Examples thereof include acetic esters such as butyl acetate, N, N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, water, and a mixed solvent thereof. When a solvent is used, a maleic anhydride copolymer may be used. An amidated compound can be synthesized by dissolving or dispersing in a solvent and adding an amine compound. According to the present invention, a copolymer containing a succinimide unit represented by the general formula (I) is obtained by heating the above amidated maleic anhydride copolymer in the presence of a stabilizer and subjecting it to ring-closing imidization. Things. Here, in this step, the amidated maleic anhydride copolymer can be used as polymer particles, a polymer solution or a dispersion solution, but from the viewpoint of economical efficiency such as simplification of the process and productivity, the solvent is used. It is preferred to use no solvent or in the presence of a small amount of a solvent such as 10 parts by weight or less based on 100 parts by weight of the amidated maleic anhydride copolymer. The imidization temperature is 100 to 400 ° C.
Preferably from 120 to 350 ° C., particularly preferably from 140 to 350 ° C.
When the reaction temperature is lower than 100 ° C., the imidization reaction is difficult to proceed. When the reaction temperature is higher than 400 ° C., the obtained copolymer may be colored due to thermal deterioration. The reaction temperature can be raised or lowered continuously or stepwise. Further, various basic or acidic catalysts such as triethylamine and toluenesulfonic acid can be added as a reaction catalyst. Also,
The imidization rate in the above imidization is affected by the reaction temperature, the reaction time, etc., but in order to obtain a copolymer having sufficient heat resistance, maleic anhydride units contained in the copolymer are removed. On a basis, it is preferable that 80 mol% or more, preferably 95 mol% or more, particularly 99 mol% or more thereof is converted to succinimide units. If the conversion is less than 80 mol%, the thermal stability of the resulting copolymer may be impaired. The stabilizer used in the production method of the present invention includes:
One or more compounds selected from a phosphorus-based stabilizer, a phenol-based stabilizer, a sulfur-based stabilizer, and an amine-based stabilizer. Examples of the phosphorus-based stabilizer include triphenylphosphite, 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; Further, as a phenol-based 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-
Hydroxynamamide), 3,5-di (t-butyl)-
4-hydroxy-benzylphosphonate-diethyl ester and the like. Further, examples of the sulfur-based stabilizer include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and examples of the amine-based stabilizer include 2-
Bis (1,2,2,2,3,5-di (t-butyl) -4-hydroxybenzyl) -2- (n-butyl) malonate
6,6-pentamethyl-4-piperidyl), bis (2,
2,6,6-tetramethyl-4-piperidinyl) sebacate and the like. In addition, two or more of these stabilizers may be used in combination. Among them, a phosphorus-based stabilizer or a combined system of a phosphorus-based stabilizer and a phenol-based stabilizer is particularly preferable. When a combined system of a phosphorus-based stabilizer and a phenol-based stabilizer is used, a phosphorus-based stabilizer / phenol-based stabilizer is used. The weight ratio of the agents is 100/0 to 5/95, especially 90/10 to 50
/ 50 is preferable. The amount of these stabilizers is 0.00 0.00 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. When the amount added is 0.
If the amount is less than 005 parts by weight, the effect of improving yellowness may be reduced, and if it exceeds 5 parts by weight, it is not economical. The reactor used in the production method of the present invention is not particularly limited, and a tank reactor, a tube reactor, a screw extrusion reactor, or the like can be used. In particular, from the viewpoint of color tone improvement and economy,
It is preferable to use an extruder with a deaerator, and heat and melt a mixture of the amidated maleic anhydride copolymer particles and a stabilizer using an extruder with a deaerator, and water and excess amine generated by the reaction. It is preferred to carry out ring-closing imidation while removing the like. If necessary, a heat stabilizer, an ultraviolet stabilizer, various lubricants, dyes, antistatic agents, various plastics, elastomers, etc. may be added to the copolymer obtained in the production method of the present invention. May be. The resin obtained by the production method of the present invention is
It has excellent color tone and transparency, and is useful in a wide range of applications such as various optical parts, automobile parts, electric and electronic parts, and medical food parts.
In addition, a product excellent in color tone can be obtained even in a composite with various plastics or elastomers. 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 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 a Ubbelohde viscometer using dimethylformamide (DMF) as a solvent. Further, the yellowness of the obtained polymer is J
Based on IS K5401, 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: 82.22, z: 94.51). Reference Example 1 Synthesis of Maleic Anhydride / Isobutene Copolymer In a 30-liter 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 were placed. After 6.3 g of t-butyl peroxypivalate and 19 l of isopropyl acetate were charged and purged several times with nitrogen, 5.2 l of liquefied isobutene was charged and reacted at 60 ° C. for 6 hours. The obtained particles are dried after centrifugation, and 4.4.
kg of maleic anhydride / isobutene copolymer was obtained. From the elemental analysis, the obtained copolymer contained 50 mol% of maleic anhydride units. The relative solution viscosity is 2.0
Met. Several batch reactions were performed in the same manner to prepare a maleic anhydride copolymer sample. Example 1 30 stirrer equipped with a stirrer, nitrogen inlet tube, thermometer and degassing tube
1 kg of the copolymer particles obtained in Reference Example 1 and 20 l of toluene were charged into an 1 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 maleic anhydride / isobutene copolymer. The obtained copolymer was analyzed by IR for 18
The disappearance of the absorption based on the acid anhydride at 50 cm ^-1 and the new absorption based on the amide and carboxylic acid units were confirmed, thereby confirming 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 is shaken and mixed with the amidated maleic anhydride / isobutene copolymer particles, and the mixture is placed under the hopper in the direction of the tip nozzle toward the tip nozzle.
C., 260 ° C., 280 ° C., 270 ° C., using a twin-screw extruder, continuously extruding under a nitrogen atmosphere, extruding while removing water, excess amine, etc. generated by the reaction with a vent, to obtain a transparent strand. Got. The obtained strand was cut to obtain a transparent pellet. From the results of elemental analysis, IR measurement and ¹³ C-NMR measurement, it was confirmed that the obtained copolymer was a copolymer comprising 50 mol% of N-methylsuccinimide units and 50 mol% of isobutene units. The yellowness of the obtained polymer was 4.5. The obtained pellets were subjected to injection molding using a minimat (manufactured by Sumitomo Heavy Industries, Ltd.) at an injection temperature of 300 ° C. and a mold temperature of 120 ° C. to produce test pieces. Bending strength of the obtained specimen is 1300 kg / cm ^2, the flexural modulus 46000kg / cm ^2, heat distortion temperature 145
° C. Example 2 By the same operation as in Example 1, 0.15 parts by weight of pentaerythrityl-tetrakis [3- (3,5
-Di (t-butyl) -4-hydroxyphenyl) propionate]. The yellowness of the obtained polymer was 6.7. Example 3 In the same manner 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 yellowness 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 and 0.05 part by weight of pentaerythrityl were used as stabilizers. -Tetrakis [3- (3,5-di (t-butyl) -4-
[Hydroxyphenyl) propionate] was added to extrude the copolymer. The yellowness of the obtained polymer was 4.2. Comparative Example 1 In the same manner as in Example 1, a copolymer was extruded without adding a stabilizer. The yellowness of the obtained polymer was 10.8. As described above, a copolymer containing a succinimide unit having low yellowness and excellent transparency can be obtained by the production method of the present invention.
It is useful in many fields including automobile parts and electric and electronic parts.

Claims (1)

(57) [Claim 1] 40-60 mol% of maleic anhydride units and isobutene units 6 having a relative solution viscosity of 0.1-10.0.
0 to 40 mol% and other copolymerizable monomer units 0 to 0
In producing a copolymer containing a succinimide unit represented by the general formula (I) by reacting a maleic anhydride copolymer consisting of 20 mol% with one or more amine compounds, The amidation is performed in the presence of at least one stabilizer selected from a phosphorus-based stabilizer, a phenol-based stabilizer, a sulfur-based stabilizer and an amine-based stabilizer.
A method for producing a copolymer, which comprises subjecting a ring-closed imidization by heating. Embedded image (Where R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group)