JPH05125130A - Production of graft copolymer - Google Patents

Abstract

PURPOSE:To obtain a graft copolymer excellent in heat resistance, rigidity and impact resistance by graft polymerization of a monomer mixture comprising an unsaturated dicarboxylic anhydride and an olefin followed by reaction of an alkylamine to carry out imidation. CONSTITUTION:A monomer mixture comprising (A) an unsaturated dicarboxylic anhydride such as maleic anhydride and (B) an olefin such as isobutene is put to graft polymerization in the presence of a rubbery compound such as polybutadiene using a free radical initiator like benzoyl peroxide, and a primary alkylamine such as N-methylamine is then made to react with the resulting copolymer to carry out imidation, thus obtaining the objective copolymer useful in wide applications such as those in the automotive, electrical/electronic, precision machinery, housing, food, or medical industries.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a graft polymer having excellent heat resistance, rigidity and impact resistance.

[0002]

2. Description of the Related Art Various studies have been made on maleimide copolymers because they have high heat resistance. For example, a method of copolymerizing methyl methacrylate with an N-aromatic substituted maleimide is disclosed in JP-B-43-9753 and JP-A-61-14.
1715, JP-A-61-171708 and JP-A-62-109811, a method of copolymerizing an N-aromatic substituted maleimide with a styrene resin is disclosed in JP-A-47-6891. It is disclosed in JP-A-61-76512 and JP-A-61-276807.

However, the resin obtained by this method is N-
As the aromatic substituted maleimide content increases, the heat resistance becomes better, but there are problems such as very brittle, poor processability, and coloration. A small amount as a heat resistance improver for acrylonitrile / butadiene / styrene (ABS) resin. It is only used as added.

On the other hand, N-alkyl-substituted maleimide-olefin copolymers are interesting polymers having properties such as excellent heat resistance, high rigidity and practical mechanical strength, but further improvement in impact strength is desired. It is rare.

Japanese Patent Publication No. 49-12576 discloses a resin composition of a maleimide copolymer and a rubber, which is a simple blend and has a small effect of improving bending strength and impact strength. Is.

[0006]

An object of the present invention is to provide a method for producing a graft copolymer having excellent heat resistance, rigidity and impact resistance.

[0007]

Means for Solving the Problems As a result of intensive studies in view of this problem, the present inventors have found that a monomer mixture containing an unsaturated dicarboxylic acid anhydride and olefins is radical-initiated in the presence of a rubber-like compound. It was found that a graft copolymer satisfying the above purpose can be produced by reacting a copolymer obtained by graft polymerization with an agent with a primary alkylamine to imidize, and completed the present invention.

Examples of the unsaturated dicarboxylic acid anhydride used in the present invention include maleic anhydride, citraconic anhydride, itaconic anhydride and the like, with maleic anhydride being preferred.

The above olefins in the present invention 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-methyl-2-pentene, 2-methyl-2-hexene and the like can be mentioned, of which heat resistance and mechanical properties From the viewpoint of characteristics, 1,1-disubstituted olefins, particularly isobutene, are preferable. These are 1 or 2
A combination of two or more species can be used.

Further, if necessary, other vinyl type monomers may be mixed with the monomer mixture containing the above unsaturated dicarboxylic acid anhydride and olefins within a range not impairing the object of the present invention. Absent.

Other vinyl monomers include styrene, α-methylstyrene, vinyltoluene, 1,3-
Butadiene, isoprene and their halogen-substituted derivatives, methacrylic acid, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, and other methacrylate esters, methyl acrylate, acrylic acid Acrylic esters such as ethyl, butyl acrylate, cyclohexyl acrylate, phenyl acrylate and benzyl acrylate, vinyl esters such as vinyl acetate and vinyl benzoate, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether,
One or more compounds selected from vinyl ethers such as butyl vinyl ether and monomers such as vinyl chloride, vinylidene chloride, acrylonitrile and the like can be mentioned.

The rubber-like compound used in the production method of the present invention means an elastic body or a viscous body having a glass transition temperature of 10 ° C or lower, preferably 0 ° C or lower, and more preferably -20 ° C or lower.

Examples of these rubber compounds include dibutadiene rubbers such as polybutadiene, styrene / butadiene copolymers, acrylonitrile / butadiene copolymers, methyl methacrylate / butadiene copolymers, polyisoprene and polychloroprene, or hydrogenated products thereof. , Polyethylene, ethylene / propylene / ethylidene norbornene copolymer,
Olefin elastomer such as butyl rubber, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, acrylic acid such as ethyl acrylate / butyl acrylate copolymer, ethyl acrylate / allyl acrylate copolymer Acrylic rubber based on ethyl, silicones, fluorine rubber, urethane rubber, ester rubber,
Examples thereof include amide rubber.

The molecular weight of these rubber compounds is not particularly limited, but the molecular weight is 1000 or more, particularly 1000.
Those having a molecular weight of 0 or more are preferable, and these rubber-like compounds may be crosslinked, or the properties of the copolymer obtained by forming a structure such as a core shell can be improved.

Further, it is preferable that these rubber compounds have a double bond, a halogen group, a thiol group and the like in order to produce a graft copolymer.

Properties such as low temperature impact resistance, oil resistance, moldability, and weather resistance can be imparted to the resulting graft copolymer by selecting a rubber-like compound. Among them, if a diene elastomer is used, low temperature impact resistance is obtained. A copolymer with excellent properties
By using an olefin elastomer and an acrylic elastomer, a copolymer having particularly excellent weather resistance and impact resistance can be obtained.

For the polymerization of these copolymers, any of known polymerization methods such as bulk polymerization method, bulk-suspension polymerization method, solution polymerization method, suspension polymerization method and emulsion polymerization method can be adopted.

Examples of the polymerization initiator in these polymerizations include benzoylperoxide, laurylperoxide, octanoylperoxide, acetylperoxide, di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, t-butylperoxide. -Oxyacetate, organic peroxide such as t-butylperoxybenzoate, or 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-butyronitrile), 2 , 2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 1,1'-azobis (cyclohexane-1-
Examples thereof include azo initiators such as carbonitrile).

The polymerization temperature can be appropriately set according to the decomposition temperature of the initiator, but it is generally preferably carried out in the range of 40 to 300 ° C.

Solvents usable in the solution polymerization method include benzene, toluene, xylene, ethylbenzene,
Cyclohexane, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide,
Examples include isopropyl alcohol and butyl alcohol.

Among these polymerization methods, emulsion polymerization can be carried out, for example, by introducing an unsaturated dicarboxylic acid anhydride, an olefin and an initiator in the presence of a rubber latex.

The content of the rubber-like compound in the graft copolymer obtained by the above-mentioned polymerization is 3 to 60% by weight,
Preferably 5 to 50% by weight, particularly preferably 10 to 4
It is 0% by weight. If the content of the rubber-like compound exceeds 60% by weight, the mechanical properties and moldability of the resulting copolymer may deteriorate, and if it is less than 3% by weight, the impact resistance of the obtained copolymer is improved. May be less effective.

The unsaturated dicarboxylic acid anhydride / olefin copolymerization composition ratio in the above graft copolymer is 30 to 70/70 to 30 mol%, and in ordinary polymerization, it is 45 to irrespective of the charged composition. 55/55 to 45 mol%.

In the present invention, these graft copolymers are reacted with a primary alkylamine for imidization. The imidization reaction can be carried out in a solution state, a suspension state or a molten state. In addition, a catalyst may be present at the time of imidization. Examples of the catalyst include tertiary amines. It is preferable to carry out these imidization reactions in nitrogen.

The primary alkylamine used in the imidization reaction includes N-methylamine, N-ethylamine and N-
n-propylamine, N-i-propylamine, N-n
-Butylamine, N-i-butylamine, Ns-butylamine, Nt-butylamine, Nn-pentylamine, Nn-hexylamine, Nn-heptylamine, Nn-octylamine, N -Laurylamine, N
-Stearylamine, N-cyclopropylamine, N-
N such as cyclobutylamine and N-cyclohexylamine
-Alkylamines are mentioned, and those having an alkyl group having 1 to 4 carbon atoms and a cycloalkyl group having 3 to 6 carbon atoms are preferable from the viewpoint of heat resistance, and particularly N-methylamine, N-ethylamine, N-isopropylamine and N-cyclohexylamine are preferred. These can be used alone or in combination of two or more.
Furthermore, N-aromatic amine, ammonia, etc. can be partially used.

When the imidization reaction is carried out in a solution state or a suspension state, it is preferable to use a reactor such as an autoclave, and when it is carried out in a molten state, an extruder equipped with a degassing device is used. Is also good. Also, these reactors can be used in combination.

The temperature of the imidization reaction is usually about 30-35.
It is carried out at 0 ° C, particularly preferably at 80 to 320 ° C. If the reaction temperature exceeds 350 ° C., the physical properties of the copolymer may deteriorate due to thermal decomposition. These reaction temperatures can be raised continuously or stepwise.

The imidization ratio can be determined by measurement such as ¹³ C-NMR, IR, elemental analysis and the like. The imidation ratio in the production method of the present invention is preferably 50% or more, more preferably 80% or more, and particularly preferably 95% or more.

The graft ratio of the copolymer can be determined by solvent extraction or the like. According to the production method of the present invention, (amount of charged rubber-amount of unreacted rubber) / amount of charged rubber × 10
The graft ratio represented by 0 is 5% or more, preferably 50
% Or more, particularly preferably 80% or more, and the unreacted rubber component may be present in the graft copolymer.

The graft copolymer obtained according to the present invention has a melt viscosity of 10 to 10 at a shear rate of 10 ³ sec ^-1 at a temperature of heat distortion temperature + (100 to 200 ° C.).
Approximately 00000 poise, especially 100 to 10,000
0 poise is preferable.

The copolymer obtained by the present invention is
In addition to this, N-alkylmaleimide / olefin copolymer,
Alternatively, a polymer obtained by imidizing an unsaturated dicarboxylic acid anhydride / olefin copolymer with a primary amine can also be used.

If necessary, polyethylene, polypropylene, polyvinyl chloride, polystyrene, styrene /
Acrylonitrile copolymer, styrene maleic anhydride copolymer, acrylic resin, imidized acrylic resin, polyamide, polyester, polycarbonate, polyacetate
Homopolymer of polyphenol, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, polyamideimide, polyimide, silicone resin, fluorine resin, phenol resin, epoxy resin, diene rubber, olefin rubber, acrylic rubber, etc. Random, block, graft copolymers and mixtures or modified products thereof may be mixed and used.

Further, various dyes, glass fibers, carbon fibers,
Potassium titanate, asbestos, silicon carbide, ceramic fiber, metal fiber, silicon nitride, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, zeolite, mica, mica, talc, ferrite, calcium silicate, calcium carbonate, magnesium carbonate Inorganic and organic fillers such as antimony trioxide, zinc oxide, titanium oxide, iron oxide, glass balun and aramid fiber, heat stabilizers such as hindered phenol and organic phosphate, benzotriazole type or A UV stabilizer such as a hindered amine-based stabilizer, a flame retardant, a flame retardant aid, a foaming agent, an antistatic agent, and various lubricants may be added and used. These additives may be used in combination.

The resin obtained in the present invention can be molded into various molded products, sheets, films, fibers and the like by known injection molding, extrusion molding, blow molding, foam molding, vacuum molding and the like. it can. Further, it is possible to subject the obtained molded body to treatments such as plating, painting and printing.

[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 IR measurement, ¹³ C
-NMR measurement and elemental analysis were performed. The molecular weight of the obtained polymer was determined by gel permeation chromatography.
(HLC-802A manufactured by Tosoh Corporation) was used to calculate the polystyrene conversion.

The obtained sample was 240-320 using a twin-screw extruder (Laboplast Mill (manufactured by Toyo Seiki Co., Ltd.))
Pellets were obtained at ℃, and the obtained pellets were injection-molded using an injection molding machine (Panajection (Matsushita Electric Industrial Co., Ltd.)) at a cylinder temperature of 240 to 350 ℃ and a mold temperature of 60 to 120 ℃ to measure physical properties. It was used as a sample.

The heat distortion temperature of the obtained sample is ASTM
D648 (18.5 kg / cm ² load), flexural strength and flexural modulus were measured according to ASTM D790, and notched impact strength was measured according to ASTM D256, respectively.

Example 1 A 30-liter autoclave equipped with a stirrer, a nitrogen introducing tube, an isobutene introducing tube, a thermometer and a degassing tube was charged with 208 g of polybutadiene (BR01; manufactured by Nippon Synthetic Rubber Co., Ltd.) and 18 l of dioxane, After the polybutadiene was dissolved, 1180 g of maleic anhydride and 24 g of benzyl peroxide (BPO) were charged, and after purging with nitrogen several times,
Liquefied isobutene (1.8 l) was charged and polymerization was carried out at 70 ° C for 10 hours.

The reaction contents were poured into an excess of methanol to precipitate a polymer, and the polymer was separated by centrifugation.
It was dried under reduced pressure at 60 ° C. for 24 hours. The yield was 2130g.

1000 g of the obtained polymer was dissolved in dimethylformamide (DMF), 1.1 mol equivalent of N-methylamine was added to maleic anhydride group, and the mixture was stirred at 60 ° C. for 2 hours. 6 at 180 ° C
A time reaction was performed.

A part of the obtained polymer was taken out ¹³ C-
As a result of NMR measurement, the conversion rate from maleic anhydride to an imide group was almost 100%. When Soxhlet extraction was performed using toluene as a solvent, the extraction residue was 96%, and IR absorption analysis of the extraction residue confirmed the characteristic absorption derived from polybutadiene and the characteristic absorption derived from the imide group. I confirmed that it was generated.

The obtained sample was pelletized using a twin-screw extruder, and a test piece was prepared by injection molding. The characteristic evaluation results are shown in Table 1.

Reference Example 1 The reactor described in Example 1 was charged with 1180 maleic anhydride.
g, 24 g of BPO and 18 l of dioxane were charged and purged several times with nitrogen, then 1.8 l of liquefied isobutene was charged and polymerization was carried out at 70 ° C. for 10 hours.

The reaction contents were poured into excess methanol to precipitate a polymer, and the polymer was separated by centrifugation.
It was dried under reduced pressure at 60 ° C. for 24 hours. The yield was 1815 g.

As a result of elemental analysis of the obtained sample, the maleic anhydride unit in the copolymer was 50 mol%. The obtained sample was dissolved in DMF, 1.1 mol equivalent of N-methylamine was added to the maleic anhydride group, and the mixture was stirred at 60 ° C. for 2 hours and further reacted at 180 ° C. for 6 hours. went.

The imidation ratio of the produced polymer was 99% by elemental analysis and ¹³ C-NMR measurement. Several batch polymerizations were performed under the same conditions to prepare samples.

Example 2 Using the same reactor as in Example 1, polybutadiene 46 was used.
3 g and 1180 g of maleic anhydride were added to 18 l of toluene.
BPO (24 g) and charged with nitrogen several times, and then liquefied isobutene (1.8 l) was added.
The reaction was carried out for 2 hours.

The reaction contents were poured into an excess of methanol to precipitate a polymer. After centrifugation, 24 at 60 ° C under reduced pressure
Dried for hours. The yield was 2220 g.

The obtained copolymer was dispersed in toluene,
Imidization was performed using N-methylamine. The imidization ratio was almost 100%. The results of the characteristic evaluation are shown in Table 1.

Comparative Example 1 850 g of the sample prepared in Reference Example 1 was uniformly dispersed in a toluene solution in which 150 g of polybutadiene was dissolved, and then the polymer was precipitated with an excess of methanol.
After being separated and dried, pelletization and injection molding were performed in the same manner, and the characteristics were evaluated. The results obtained are shown in Table 1.

Comparative Example 2 Sample 800 obtained in Reference Example 1 as in Comparative Example 1
g and a polybutadiene 200 g sample was prepared and the characteristics were evaluated. The results obtained are shown in Table 1.

[0053]

[Table 1]

[0054]

As is apparent from the examples, the samples obtained by the production method of the present invention have various excellent properties such as excellent heat resistance, impact resistance and rigidity, and therefore, are It is extremely useful in a wide range of applications such as electric and electronic, precision machinery, housing, food and medical fields.

Claims (1)

[Claims] 1. A primary alkylamine is added to a copolymer obtained by graft-polymerizing a monomer mixture containing an unsaturated dicarboxylic acid anhydride and an olefin in the presence of a rubber compound with a radical initiator. A method for producing a graft copolymer, which comprises reacting and imidizing.