JPH0247148A - Heat-resistant and impact-resistant polyvinyl chloride mixture, method for molding and molded item - Google Patents

Abstract

PURPOSE:To obtain a heat-resistant and impact-resistant PVC mixture by graft- copolymerizing a specified N-substd. maleimide and vinyl chloride in the presence of a rubber and simultaneously compounding an additive contg. a stabilizer therewith. CONSTITUTION:The title mixture is prepd. by adding 1-70 pts.wt. additive contg. at least a stabilizer to 100 pts.wt. copolymer powder (A) obtd. by graft- copolymerizing N-substd. maleimide of formula [wherein R is 1-30C (substd.) aliph. or alicyclic group] (e.g., N-cyclohexylmaleimide) and vinyl chloride in the presence of a rubber (e.g., a crosslinked acryl rubber, an ethylene-vinyl acetate copolymer etc.) and consisting of 1-15wt.% constituting units derived from the rubber, 0.2-5.0wt.% constituting units derived from N-substd. maleimide and the remaining constituting units derived from vinyl chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-resistant, impact-resistant polyvinyl chloride mixture, a molding method, and a molded article.

[Prior art]

Vinyl chloride resin is widely used because hard, semi-hard, or soft products can be obtained by co-firing with heat and light stabilizers, lubricants, fillers, colorants, etc.

In the hard field, polyvinyl chloride powder is directly extruded using an extruder (hereinafter referred to as powder extrusion), corrugated sheets,
It is used in a wide range of applications such as pipes, decking materials, building materials, cable ducts, and joint boards.

In recent years, there has been a demand for a balance between heat resistance and impact resistance for these molded products.
17, JP-A-58-33918, etc., blends of vinyl chloride homopolymers, heat-resistant polymers, and impact modifiers have been praised.

[Problem to be solved by the invention]

However, the above method uses vinyl chloride homopolymer,
Since this was an attempt to obtain a molded product by blending different types of polymers, such as a heat-resistant polymer and an impact modifier, which inherently lack compatibility, there was a problem in that it was difficult to obtain a uniform molded product.

In some cases, the problem can be avoided by further extruding the pellet compound using a kneading machine such as a pelletizer instead of powder extrusion in order to obtain a uniform molded product, but this results in low productivity and high price, making it difficult to achieve industrially and economically. It will be disadvantageous.

When only a vinyl chloride homopolymer is used, the above-mentioned problems can be avoided because different types of polymers that inherently lack compatibility are not used, but an improvement in the balance between heat resistance and impact resistance cannot be expected.

[Means to solve the problem]

The present inventor conducted extensive research in order to solve the above problems,
This has led to the completion of the present invention.

That is, the heat-resistant, impact-resistant polyvinyl chloride mixture, molding method, and molded article of the present invention are characterized by (a) -formation (1) in the presence of rubber (wherein R is a substituted or unsubstituted polyvinyl chloride mixture having 1 to 30 carbon atoms). A copolymer obtained by graft copolymerizing an N-ff substituted maleimide vinyl chloride monomer (representing a substituted aliphatic or alicyclic group), comprising structural units 1 to 15 derived from rubber. (b) At least a stabilizer is added to 100 parts by weight of a copolymer powder consisting of 0.2 to 5.0% by weight of structural units derived from N-substituted maleimide and the remainder derived from vinyl chloride. The present invention also provides a heat-resistant and impact-resistant polyvinyl chloride mixture characterized by comprising 70 to 1 part by weight of an additive. This is a method for molding a heat-resistant and impact-resistant polyvinyl chloride mixture, which is characterized by extrusion processing. Furthermore, the present invention is a heat-resistant and impact-resistant polyvinyl chloride molded product obtained by molding the polyvinyl chloride mixture by the molding method described above.

The vinyl chloride copolymer powder used in the present invention is a powder obtained by graft copolymerizing an N-substituted maleimide represented by -formation (1) and a vinyl chloride monomer (hereinafter referred to as graft copolymer) in the presence of rubber. The polymerization method may be any known vinyl chloride polymerization method, such as suspension polymerization method, bulk polymerization method, emulsion polymerization method, solution polymerization method, etc. The suspension polymerization method is industrially and economically advantageous, and the ratio of vinyl chloride to water in the production of this graft copolymer is generally 80 to 3 parts by weight of water to 100 parts by weight of vinyl chloride.
00 parts by weight, and the polymerization temperature is 30-80°C. The polymerization initiator that can be used here is not particularly limited as long as it is used in the polymerization of vinyl chloride in -II, such as percarbonates, peresters, diacyl peroxides, azo compounds, water-soluble Examples include peroxides and water-soluble azo compounds, and these may be used alone or in combination of two or more. Examples of dispersants used include polyvinyl alcohols, cellulose derivatives, maleic anhydride-styrene copolymers, maleic anhydride-methyl vinyl ether copolymers, polyvinylpyrrolidone, and gelatin. Alternatively, a mixture of two or more types is used. Furthermore, an emulsifier may be added if necessary.

Rubbers used in the present invention include, for example, ethylene/acrylic acid ester copolymers such as ethylene/ethyl acrylate copolymer, ethylene/methyl methacrylate copolymers such as ethylene/methyl methacrylate copolymer, ethylene/methyl methacrylate copolymer, etc.
Vinyl acetate copolymer (IIVA), chlorinated polyethylene, butyl rubber, crosslinked acrylic rubber, polyurethane, polybutadiene/styrene/methyl methacrylate (MBS)
), polybutadiene/acrylonitrile/(α-methyl)styrene (ABS), styrene/butadiene copolymer, and the like. These may be used alone or in combination of two or more, and their form may be, for example, latex, salted-out latex, salted-out latex, washed with water, and dried, etc., which require weather resistance. For extrusion molded products, it is preferable to use rubber that does not contain double bonds in its main chain.

The number of structural units derived from rubber in the graft copolymer is 1 to 1.
It is 5% by weight, preferably 2 to 10% by weight. If the amount of structural units derived from rubber is less than 1% by weight, no improvement in impact resistance can be expected, and if it exceeds 15% by weight, no improvement in heat resistance can be expected.

Specific examples of the N-substituted maleimide of general formula (1) used in the present invention include N.methylmaleimide, N.
Ethylmaleimide, N-n-propylmaleimide, N.
Isopropylmaleimide, N-n-butylmaleimide,
N.t-butylmaleimide, N.laurylmaleimide,
Examples include N-bicyclo (2,2,1)-heptyl-2-methylmaleimide, N-cyclohexylmaleimide, and among others, N-t-butylmaleimide, N-bicyclo(
2,2,1).heptyl 2-methylmaleimide, N.cyclohexylmaleimide, etc. are preferably used.

For example, N-phenylmaleimide has poor reactivity with vinyl chloride monomers, while O-chlorophenylmaleimide has good reactivity with vinyl chloride monomers.
This is not preferable because there are adverse effects, such as strong coloring of the obtained graft copolymer, which are thought to be due to the resonance of the electronic states of the benzene ring and the maleimide group.

The content of the structural unit derived from N-substituted maleimide in the graft copolymer is 0.2 to 5.0% by weight, preferably C1. O
~3.0% by weight. If the content of the structural unit derived from N-substituted maleimide is less than 0.2% by weight, no improvement in heat resistance can be expected, and if it exceeds 5.0% by weight, the resulting graft copolymer will have poor thermal stability, which is preferable. do not have.

The degree of polymerization of the graft copolymer used in the present invention was determined as follows since rubber is often not soluble in nitrobenzene. 5 g of the graft copolymer was dissolved in 250 cc of tetrahydrofuran and centrifuged to remove the precipitate. Methanol 41 is gradually added dropwise to the solution to reprecipitate the copolymer. The reprecipitate was filtered, dried in a vacuum dryer, and used as a sample for measuring the degree of polymerization according to JIS-6721 method.

The degree of polymerization of the graft copolymer in the present invention determined by the above method is 700 to 3000, preferably 800 to 18
It is 00. If the degree of polymerization is less than 700, heat resistance,
No improvement in impact resistance can be expected, and if it exceeds 3000, molding becomes difficult and is not suitable for practical use.

The polyvinyl chloride mixture of the present invention refers to 100 parts by weight of the above-mentioned graft copolymer, and at least 70 to 1 part of an additive containing at least a stabilizer and all or a part of a lubricant, filler, colorant, etc. shown below. Parts by weight are mixed, preferably 100:40 to 1 part by weight, more preferably 100:25 to 1 part by weight, respectively. The additive is 70
If the amount exceeds 1 part by weight, the surface condition of the molded product will be poor and it will not be suitable for practical use, and if it is less than 1 part by weight, the thermal stability will decrease and moldability will deteriorate.

The stabilizer used in the present invention may be any known stabilizer, such as lead white, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, tribasic maleic acid. Lead salt stabilizers with lead, lead silicate and their silica gel co-precipitates, metal soaps such as magnesium soap, calcium soap, barium soap, cadmium soap, zinc soap, lead soap, tin soap, cadmium-barium type soaps, Liquid stabilizers such as cadmium-barium-zinc type and barium-zinc type, organotin type such as tin alkyl sulfur compounds, tin aryl sulfur compounds, tin alkyl oxygen compounds, tin aryl oxygen compounds, organotin carboxylic acids, and organotin mercaptides. stabilizer,
Glycidyl ethers and epoxy resins, epoxidized fats and oils and alkyl esters of epoxidized natural fatty acids and resin acids, epoxy stabilizers such as epoxy derivatives of cyclohexane, organic compounds such as trialkyl phosphites, triphenyl phosphites, triallylphosphites, etc. Stabilizers against heat such as phosphorous acid compounds, polyhydric alcohols, and amine compounds; ultraviolet absorbers such as salicylate esters and benzoate esters, benzophenones, benzotriazoles, and acrylonitrile; and ultraviolet rays such as phosphorus compounds. Examples include stabilizers and stabilizers against light such as titanium oxide.

In addition, as a lubricant, for example, magnesium stearate, calcium stearate, barium stearate,
Metal soaps such as zinc stearate and lead stearate, liquid paraffin, natural paraffin, polyethylene wax, hydrocarbons such as chlorinated hydrocarbons and fluorocarbons,
Fatty acids such as stearic acid, behenic acid, araxic acid, and oxyfatty acids, fatty acid amides such as fatty acid amides, fatty acid amides such as alkylene bis fatty acid amides, fatty acid esters such as fatty acid lower alcohol esters, fatty acid polyglycol esters, fatty acid fatty alcohol esters, and polyvalent fatty acids. Examples include alcohol, polyglycol, polyglycerol, partial esters of fatty acids and polyhydric alcohols, partial esters of fatty acids and polyglycols, and partial esters of fatty acids and polyglycerols.

Examples of fillers include calcium carbonate, clay, hydrated silicic acid, anhydrous silicic acid, calcium silicate, aluminum silicate, asbestos, antimony oxide, talc, aluminum trihydrate, hydrated zinc borate, magnesia, baking soda, and nitric acid. processing,
Examples include calcium hydroxide, mica, and synthetic fluorinated mica.

As the coloring agent, for example, azo pigment, azo lake,
Azo pigments such as insoluble azo and condensed azo, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, vat dye pigments such as anthraquinone, perylene, thioindico, and isoindoline, basic dye lakes, and acid dyes. Examples include dyeing lake pigments such as lake, quinacridone pigments, dioxazine pigments, etc. Inorganic pigments include precipitated pigments such as chromates, molybdates, oxides, cyanides, oxides, sulfides, etc. Examples include precipitated fired pigments, oxide based pigments, fired pigments such as ultramarine blue and cobalt blue, metal powders, and var pigments.

Furthermore, antistatic agents, heat resistance improvers, processing aids, flame retardants, smoke suppressants, antioxidants, etc., which are blended into polyvinyl chloride, are added to -a within a range that does not impair the purpose of the present invention. Good too.

As a method for mixing the graft copolymer and an additive containing at least a stabilizer in the present invention, for example, the mixture of the present invention can be obtained by mixing using a known mixing device such as a ribbon blender or a Henschel mixer. Can be done.

In molding the polyvinyl chloride mixture of the present invention, the polyvinyl chloride mixture is further melt-extruded using a known kneading machine such as an extruder to obtain a molded product with excellent heat resistance and impact resistance. Can be done.

〔Example〕

The present invention will be explained below with reference to Examples, but these are merely illustrative and do not limit the scope of the present invention.

Reference Example 1 (Manufacturing example of acrylic latex) 2000 kg of deionized water was placed in a polymerization machine with an internal volume of 5 nf equipped with a stirring blade.
Anionic emulsifier 6.9 kg, ammonium persulfate 0.
68kg, n-butyl acrylate 700kg, 1.
30 kg of 3-butylene glycol dimethacrylate was added, and after the air inside was replaced with nitrogen, polymerization was carried out at 60°C. Fifteen hours after the start of polymerization, the internal temperature started to rise, so the heat was removed from the jacket, and the reaction was continued for another 10 hours while maintaining the polymerization temperature to stop the polymerization reaction. The concentration of the obtained latex was 25% by weight, and its average particle size was 0.
．． It was 07 μ-.

Reference Example 2 (Production Example of Graft Copolymer) 2700 kg of deionized water was placed in a polymerization machine with an internal volume of 71 TI equipped with a stirring blade.
Ca(OH)z 0.37kg - partially saponified polyvinyl alcohol 1.5kg, methylcellulose 1.4kg,
2.2°-azobisisobutyronitrile 0.16 kg,
2゜2゛-Azobis-2,4-dimethylvaleronitrile 0.29, N-cyclohexylmaleimide 2.05kg
After removing the internal air with a vacuum pump, reference example 1
368 kg of acrylic latex with a concentration of 25% by weight as shown in
(solid content: 92 kg) was charged under stirring to cause agglomeration, and then 1410 kg of vinyl chloride was charged and polymerization was carried out at 57°C. As the reaction progresses, the internal pressure of the polymerization machine increases to 6.5
The polymerization reaction was stopped after confirming that the weight had decreased to kg/d·G. Next, after removing unreacted vinyl chloride monomer, the slurry was dehydrated and dried by a conventional method to obtain 1301 kg of white powder particles.

The graft copolymer obtained in Reference Example 2 was used in Example 1. Although other Examples and Comparative Examples are not particularly specified, the polymerization temperature, polymerization initiator, dispersant, amount of N-cyclohexylmaleimide, The following Examples and Comparative Examples were conducted using polymers obtained by changing the type of rubber.

In each example and comparative example, the graft copolymer 100
The following additives were added to the weight parts.

Examples-1 to 3 and Comparative Examples-1 to 7.9 contain 2 parts by weight of tribasic lead sulfate, 1 part by weight of dibasic lead stearate, 1 part by weight of lead stearate, and 0.5 part by weight of stearic acid. In Example 4 and Comparative Example 8, 15.2 parts by weight and 95.2 parts by weight of calcium carbonate were added in addition to the above additives.

Mix these on each side using a Henschel mixer, and use a 30mrgφ different-direction twin-screw extruder to give a thickness of 3m+m.
, medium 40T+111 joint boards were extruded and evaluated.

- The Vicat softening point was measured using a load of 5 kgf according to the method of JIS K-7206.

- Charpy impact value was measured using a moment of 60 kgf-am according to the method of JIS K-7111.

・For moldability, the condition of the joint plate was evaluated using the following criteria.

0 The surface is smooth and there are no sharp corners.

0 The surface is smooth and there are slight cracks on the corners.

The surface is slightly rough and there are cracks at the corners.

×The surface is not smooth and has large cracks.

・Thermal stability is the blackening time with the gear open.

In addition, Examples 1 to 4 and Comparative Examples 1, 2, 5 to 8 were polymerized by a normal vinyl chloride polymerization method in the presence of ethylene/vinyl acetate copolymer (EVA) or crosslinked acrylic rubber (ACM). Comparative Example 3.4 was polymerized according to a normal vinyl chloride polymerization method, and Comparative Example 9 was obtained by further chlorinating polyvinyl chloride (Cl ratio 64χ) based on 100 parts by weight of chlorinated polyvinyl chloride. A blend of 15 parts by weight of polybutadiene, styrene, and methyl methacrylate (MBS) was used. The results are shown in Table-1.

〔Effect of the invention〕

The heat-resistant and impact-resistant polyvinyl chloride mixtures and molded articles obtained by the method of the present invention have an improved balance between heat resistance, especially Piccad softening temperature, and impact resistance, especially Charpy impact value, and also have heat resistance and impact resistance by powder extrusion. It exhibits good properties and has excellent moldability, making it extremely useful as heat-resistant and impact-resistant polyvinyl chloride mixtures and molded products.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. (a) In the presence of rubber, the general formula (1) ▲ Numerical formula, chemical formula, table, etc. A copolymer obtained by graft copolymerizing an N-substituted maleimide (representing a substituted aliphatic or alicyclic group) with a vinyl chloride monomer, the structural unit 1 derived from rubber.
(b) at least stable; 70 to 1 part by weight of an additive containing a heat-resistant and impact-resistant polyvinyl chloride mixture. 2. A method for molding a heat-resistant and impact-resistant polyvinyl chloride mixture, which comprises directly charging the polyvinyl chloride mixture according to claim 1 into an extruder for extrusion processing. 3. Heat resistance obtained by molding by the method according to claim 2;
Impact-resistant PVC molded product.