JPH0562127B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a thermoplastic resin having an imide group, and more particularly, to a rubber-like polymer containing a monomer consisting of an aromatic vinyl monomer, an unsaturated dicarboxylic acid anhydride, and a vinyl monomer copolymerizable with these. A method for producing a thermoplastic resin having excellent thermal stability, impact resistance, and moldability by reacting a copolymer obtained by graft polymerizing a mixture of 200% and 300% with ammonia or a primary amine using a specific radical-generating initiator. . Conventionally, aromatic vinyl monomers, rubber-like polymers,
A method for producing a copolymer by graft polymerizing maleic anhydride and a vinyl monomer copolymerizable with maleic anhydride has been proposed. (Unexamined Japanese Patent Publication No. 48-42091,
No. 49-28693, JP-A-53-78252, JP-A-53-
(No. 80490) However, although these polymers copolymerized with maleic anhydride have high heat distortion temperatures, in both cases, acid anhydride groups caused by maleic anhydride exist in the copolymer chain. Therefore, it is easy to cause chemical changes and decompose not only when exposed to water at high temperatures, but also when exposed to heat, which poses significant restrictions when forming and processing, and when the processed product is not exposed to water or steam. It has the disadvantage that mechanical properties, particularly impact strength, deteriorate when exposed to high temperatures. Also known is a method for producing a copolymer in which the acid anhydride group of these maleic anhydride copolymers is imidized with ammonia or a primary amine. (Unexamined Japanese Patent Publication 1987)
-100104) Although this improved heat stability, hot water resistance, etc., it was still insufficient to simultaneously satisfy impact resistance and fluidity during molding. As a result of intensive studies, the present inventors simultaneously improved impact resistance and fluidity during molding by using a peroxide-based radical-generating initiator and an azo-based radical-generating initiator in a specific ratio. This is the first time I have succeeded in doing so. That is, 5 to 40 parts by weight of a rubbery polymer, 50 to 90 weight % of an aromatic vinyl monomer, 5 to 50 weight % of an unsaturated dicarboxylic acid anhydride, and 0 to 30 weight % of a vinyl monomer copolymerizable with these. Monomer mixture consisting of 60% to
A copolymer graft-polymerized using 95 parts by weight as a radical generation initiator and a peroxide radical generation initiator and an azo radical generation initiator in a weight ratio of 9/1 to 1/9, ammonia or 1st
We would like to provide a method for producing a thermoplastic resin having an imide group, which is obtained by reacting with a class amine at a temperature of 80 to 350°C, and which has excellent heat resistance stability, hot water resistance, impact resistance, and fluidity during molding. That is. In the present invention, the rubbery polymer content can be selected in the range of 5 to 40% by weight based on the copolymer before imidization, depending on the impact strength required of the thermoplastic resin. As the content of the rubbery polymer increases, the impact strength improves, but when the content of the rubbery polymer exceeds 40% by weight, the heat resistance and molding processability of the final thermoplastic resin are poor, and 5 If it is less than % by weight, the impact improving effect is insufficient. Rubbery polymers include butadiene homopolymers, copolymers of butadiene and vinyl monomers copolymerizable,
Ethylene-propylene copolymers, ethylene-propylene-diene copolymers, block copolymers of butadiene and aromatic vinyl, acrylic ester polymers, and acrylic ester polymers and vinyl monomers copolymerizable therewith. Copolymers and the like are used. In the present invention, the monomers to be grafted onto the rubbery polymer include 50 to 90% by weight of aromatic vinyl monomers, 5 to 50% by weight of unsaturated dicarboxylic acid anhydrides, and 0 to 90% by weight of vinyl monomers copolymerizable with these monomers. A mixture consisting of 30% by weight and 50% by weight of aromatic vinyl monomers.
If it is less than this, the characteristics of the aromatic vinyl compound, especially in the case of styrene, the moldability and dimensional stability will be lost. Also, 5% by weight of unsaturated dicarboxylic anhydride
If it is less than 50% by weight, the heat resistance will not be sufficient, and if it exceeds 50% by weight, the copolymer will become brittle and its moldability will deteriorate significantly. Examples of the aromatic vinyl monomer in the present invention include styrene, α-methylstyrene, vinyltoluene,
These include styrene monomers such as t-butylstyrene and chlorostyrene, and substituted monomers thereof, and among these, styrene and α-methylstyrene are particularly preferred. Examples of the unsaturated dicarboxylic anhydride include anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid, with maleic anhydride being particularly preferred. Vinyl monomers that can be copolymerized with these include vinyl cyanide monomers such as acrylonitrile, methacrylnitrile, and α-chloroacrylonitrile, and acrylic esters such as methyl acrylate, ethyl acrylate, and butyl acrylate. Monomers, methacrylic acid ester monomers such as methyl methacrylic acid ester and ethyl methacrylic acid ester, vinyl carboxylic acid monomers such as acrylic acid and methacrylic acid, acryl amide, methacrylic acid amide, acenaphthylene and N-vinyl carbazole Among these, monomers such as acrylonitrile, methacrylic acid ester, acrylic acid, and methacrylic acid are preferred. In the graft polymerization of the present invention, the radical generation initiator is a peroxide radical generation initiator and an azo radical generation initiator in a weight ratio of 9/1 to 1/2.
9, preferably at a ratio of 4/1 to 1/4. Here, the peroxide-based radical generation initiator is a compound having an -O-O- group in its molecule, specifically benzoyl peroxide,
Acetyl peroxide, lauryl peroxide, bis-3.5.5-trimethylhexanol peroxide, O-methylbenzoyl peroxide, dicumyl peroxide, 1.1-di-t-butylperoxy-3.3.5-trimethylcyclohexane, 1.1- Examples include di-t-butylperoxycyclohexane, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxybenzoate, and t-butylperoxyisopropyl carbonate. Azo radical generation initiator has - in the molecule.
It is a compound having an N=N- group, and specific examples thereof include azobisisobutyronitrile, azobiscyclohexanenitrile, azobismethylpropionitrile, and azobismethylbutyronitrile.
The total amount of these radical generating initiators used may be the amount used in normal polymerization, and is preferably 0.005 to 0.5 parts by weight based on 100 parts by weight of the monomer mixture to be grafted. If the weight ratio of peroxide radical generation initiator/azo radical generation initiator exceeds 9/1, the resulting resin will not have sufficient fluidity during molding, and if it is less than 1/9, it will have poor impact resistance. There is a problem with sexuality. Ammonia and primary amines used in the imidization reaction of the present invention may be in either an anhydrous or aqueous solution state, and examples of primary amines include methylamine, ethylamine, n-propylamine, isopropylamine, Alkylamines such as butylamine, pentylamine, cyclohexylamine,
and aromatic amines such as chloro- or bromo-substituted alkylamines, aniline, tolylamine, naphthylamine, and halogen-substituted aromatic amines such as chloro- or bromo-substituted aniline, among which aniline is particularly preferred. In the present invention, the rubbery polymer - aromatic vinyl -
A catalyst may be present when the unsaturated dicarboxylic anhydride copolymer is imidized with ammonia and/or a primary amine, and a tertiary amine is usually used. When the imidization reaction is carried out in a liquid or suspended state, it is preferable to use a conventional reaction vessel, such as an autoclave, and when carried out in a bulk molten state, an extruder equipped with a devolatilization device may be used. The temperature of the imidization reaction is about 80-350°C, preferably 100-300°C. If the temperature is lower than 80°C, the reaction rate is slow and the reaction takes a long time, making it impractical. On the other hand, if the temperature exceeds 350°C, the physical properties will deteriorate due to thermal decomposition of the polymer. The imidized copolymer of maleic anhydride copolymer produced by the method described above maintains a high heat distortion temperature and has a high degree of stability against water and heat. It also has excellent impact resistance and moldability. This imidized copolymer is styrene-acrylonitrile copolymer (SAN resin), acrylonitrile-butadiene-styrene copolymer (ABS resin),
Acrylonitrile-butadiene-styrene-α-
Methyl styrene copolymer, acrylonitrile-acrylic rubber-styrene copolymer, acrylonitrile-ethylene/propylene rubber-styrene copolymer, styrene-methyl methacrylate copolymer, methyl methacrylate-butadiene-styrene copolymer, aromatic It can also be mixed with polycarbonate, aromatic polyester, polyphenylene oxide, styrene-modified polyphenylene oxide, and the like. A mixture directly with ABS resin is preferred in terms of impact resistance and moldability. Furthermore, stabilizers, flame retardants, plasticizers, lubricants, fillers, colorants, etc. can also be added. All parts and percentages in the following examples are expressed on a weight basis unless otherwise specified. Example 1 In an autoclave equipped with a stirrer, 60 parts of styrene (hereinafter abbreviated as ST), 30 parts of methyl isobutyl ketone (hereinafter abbreviated as MiBK), and polybutadiene cut into small pieces (manufactured by Asahi Kasei Corporation, Diene NF55R) were added. )
After charging 15 parts and purging the system with nitrogen gas, the rubber was dissolved by stirring at room temperature all day. Temperature 80℃
After that, maleic anhydride (hereinafter abbreviated as MAH) 40
A solution prepared by dissolving 0.09 parts of benzoyl peroxide and 0.09 parts of azobisisobutyronitrile in 250 parts of MiBK was continuously added over 8 hours. The temperature was maintained at 80° C. for an additional 4 hours after the addition. A portion of the viscous reaction solution was sampled and the amount of unreacted monomer was determined by gas chromatography, and the polymerization rate was determined to be 96% St and 99% MAH. To this polymerization solution, 37 parts of aniline and 1 part of triethylamine were added and reacted at 140°C for 7 hours. The reaction solution was cooled to 90° C., poured into 1000 parts of vigorously stirred methanol, precipitated, separated, and dried to obtain an imidized copolymer. C-13 NMR analysis showed that the conversion rate of acid anhydride groups to imide groups was 96%. 60 parts of the imidized copolymer thus obtained and acrylonitrile-
Styrene resin (manufactured by Denki Kagaku Kogyo Co., Ltd., HS-300)
40 parts were blended and the blend was extruded using a screw extruder equipped with a devolatilization device to form pellets.
Tristearyl phosphite 1 for blends
part and 0.3 part of octadecyl 3-(3.5-ditertyabutyl-4-hydroxyphenyl)-propionate. The physical properties of the composition thus obtained are shown in Table 1. Example 2 In the same way as Example 1, 55 parts of St,
After charging 10 parts of acrylonitrile, 50 parts of MiBK, and 19 parts of polybutadiene, and purging the system with nitrogen gas, the mixture was stirred at room temperature all day and night to dissolve the rubber. After setting the temperature to 80℃, add 35 parts of MAH, 0.06 parts of benzoyl peroxide, and azobisisobutyronitrile.
A solution of 0.12 parts dissolved in 250 parts of MiBK was continuously added over 8 hours. After addition, increase the temperature to 80°C for an additional 4 hours.
It was kept at ℃. From the quantitative determination of unreacted monomer, the polymerization rate is
It was 99% St, 98% MAH, and 90% acrylonitrile. To this polymerization solution, 32.4 parts of aniline and 1 part of triethylamine were added and reacted at 140°C for 7 hours. The conversion rate of acid anhydride groups to myoid groups was 97%.
Thereafter, the same procedure as in Example 1 was carried out to obtain a powder of an imidized copolymer. Further, in order to obtain an acrylonitrile-butadiene-styrene copolymer, the following operation was performed. That is, 143 parts of polybutadiene latex (solid content 35%, weight average particle size 0.35 μ, gel content 90
%), 1 part potassium stearate, 0.1 part sodium formaldehyde sulfoxylate, 0.03 part tetrasodium ethylenediamine tetraacetic acid, 0.003 part ferrous sulfur and 150 parts water.
℃, and 50 parts of a monomer mixture consisting of 70% St and 30% acrylonitrile, 0.2 parts of t-dodecyl mercaptan, and 0.15 parts of kyumene hydroperoxide were added continuously over 6 hours, and then heated to 65℃ after the addition. The temperature was raised and polymerization was carried out for 2 hours. The polymerization rate was 98% for St and 97% for acrylonitrile as determined by gas chromatography analysis. After adding an antioxidant to this latex, it was coagulated with calcium chloride, washed with water, and dried to obtain a graft copolymer as a white powder. Imidized copolymer 60 thus obtained
1 part, 30 parts of acrylonitrile-butadiene-styrene copolymer and AS resin (manufactured by Denki Kagaku Kogyo Co., Ltd.,
10 parts of AS-S) were blended, additives were added in the same manner as in Example 1, and then extruded into pellets.The physical properties of the pellets were measured and are shown in Table 1. Comparative Example 1 0.06 part of benzoyl peroxide and azobisisobutyronitrile as polymerization initiators in Example 2
An imidized copolymer was obtained in exactly the same manner as in Example 2, except that 0.12 part of benzoyl peroxide was replaced with 0.18 part of benzoyl peroxide. Polymerization rate is St95%,
It was 98% MAH and 90% acrylonitrile. The conversion rate of acid anhydride groups to imide groups was 97%. Imidized copolymer 60 thus obtained
1 part was blended with 30 parts of the same acrylonitrile-butadiene-styrene copolymer as in Example 2 and 10 parts of AS resin, and after adding additives in the same manner as in Example 2, it was extruded into pellets, and its physical properties were measured. It is shown in Table 1. Comparative Example 2 0.06 part of benzoyl peroxide and azobisisobutyronitrile as polymerization initiators in Example 2
An imidized copolymer was obtained in the same manner as in Example 2 except that 0.12 parts of azobisisobutyronitrile was replaced with 0.18 parts. Polymerization rate is St99%,
It was 98% MAH and 89% acrylonitrile. Furthermore, the conversion rate of acid anhydride groups to imide groups was 98%. Imidized copolymer 60 thus obtained
were blended with 30 parts of acrylonitrile-butadiene-styrene copolymer, 10 parts of AS resin, and a converting agent in the same manner as in Example 2, and then extruded into pellets.
The physical properties were measured and shown in Table 1.

[Table] From Table 1, it was found that the thermoplastic resin obtained by the production method of the present invention showed significant improvements in impact strength and fluidity during molding without deteriorating the conventional thermal stability, heat resistance, and hot water resistance. It will be done. The physical properties were measured by the following method. (1) Impact strength: Notched Izotsu impact strength.
According to ASTM D-256. (2) MFI (melt flow index)...temperature
270°C, load 5 kg, according to ASTM D-1238. (3) Thermal stability…Nitrogen flow 50c.c./min, temperature increase rate 10℃
The temperature is shown when the weight loss of the polymer in thermobalance analysis is 1% under the following conditions. (4) VSP (Vikatto Softening Point)...Load 5Kg, ASTM
According to D-1525. (5) Hot water resistance...According to ASTM D-256. The retention rate of the measured impact value (1) after immersing the notched Izot test piece in hot water at 100°C for 24 hours is shown.

Claims (1)

[Claims] 1. 5-40 parts by weight of rubbery polymer, 50-90% by weight of aromatic vinyl monomer, 5 parts by weight of unsaturated dicarboxylic acid anhydride.
~50% by weight, and a monomer mixture consisting of 0-30% by weight of a vinyl monomer copolymerizable with these 60-95
Using ammonia or A method for producing a thermoplastic resin having an imide group, which comprises reacting the thermoplastic resin with a class amine at a temperature of 80 to 350°C.