JPS6324606B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a modified vinyl chloride-based graft copolymer, in particular a modification that provides a soft molded product with good moldability, excellent matte appearance, and improved compression set and creep resistance. The purpose of this invention is to provide a vinyl chloride-based graft copolymer. In recent years, flexible molded products made of vinyl chloride resin have been given a matte appearance to give them a sense of luxury, and there is a high demand for this matte effect especially for automobile parts, electric wires, etc. It's summery. Conventionally, as a method to obtain soft vinyl chloride resin molded products with a matte appearance, attempts have been made to give the molded product a matte effect by molding at a lower molding temperature than usual. If the molding temperature is lowered, kneading during molding will not be carried out sufficiently, resulting in a disadvantage that the molded product will have inferior properties such as mechanical strength. Note that when molding is carried out at the molding temperature normally employed for general vinyl chloride resins without lowering the molding temperature, a molded product with a matte appearance cannot be obtained. On the other hand, vinyl chloride resins have a high apparent degree of polymerization by blending a vinyl chloride resin with a high degree of polymerization into a vinyl chloride polymer, or by adding a crosslinking agent during polymerization of vinyl chloride. Attempts have been made to improve compression set and creep resistance as well as to obtain matte molded products by producing and using this as a molding resin. However, such resins with a high apparent degree of polymerization have extremely poor processability compared to general vinyl chloride resins, and for this reason, molding of such resins requires the use of special processing machines or special processing methods. It has the disadvantage that it is necessary to use a new technique, and that the expected physical property effects are also small. In addition, in order to manufacture vinyl chloride resin with a high degree of polymerization, it is necessary to polymerize it at a lower polymerization temperature than when obtaining ordinary resin, so special conditions such as selection of polymerization initiator and production equipment are required. It has the disadvantage that it is necessary and not easy to manufacture. The present inventors solved the conventional disadvantages,
The present invention was completed as a result of intensive research to obtain a molded product with good molding processability, excellent matting effect, and excellent compression set. Acrylic ester, methacrylic ester, and styrene-based copolymer are added to 100 parts by weight of a copolymer of 0.01 to 2% by weight of this mixture with a polymerizable compound having two or more unsaturated bonds in one molecule. Grafting 1 to 100 parts by weight of a mixture of at least one monomer selected from the monomers and a polymerizable compound having two or more unsaturated bonds in one molecule at 50% by weight or less. The present invention relates to a method for producing a modified vinyl chloride graft copolymer, which is characterized by polymerization. According to the present invention, it is possible to obtain a molded product that does not have the above-mentioned disadvantages, has good workability, and has an excellent matte appearance, and at the same time has high deformation resistance represented by compression set. It has the advantage of being improved. To explain in more detail below, the copolymer to be used as the backbone polymer for graft polymerization used in the method of the present invention is vinyl chloride monomer or a monomer copolymerizable therewith (hereinafter referred to as comonomer). It is said to be a copolymer of a mixture of 2 and a polymerizable compound having two or more unsaturated bonds in one molecule. This is used to improve the desired matting effect and compression set. (total amount of comonomer and comonomer)
It is used in a range of 0.01 to 2% by weight (preferably 0.1 to 2% by weight). If more than 2% by weight is used, the copolymer will have too many crosslinks, making normal molding difficult.
If it is less than 0.01% by weight, the above effects due to the introduction of crosslinking bonds cannot be expected. Specific examples of the polymerizable compounds used for this purpose include diallyl esters of phthalic acid such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl maleate, diallyl fumarate, diallyl itaconate, and divinyl itaco. diallyl and divinyl esters of ethylenically unsaturated dibasic acids such as ester, divinyl fumarate, diallyl and divinyl esters of saturated dibasic acids such as diallyl adipate, divinyl adipate, diallyl azelate, diallyl sebacate, diallyl ether, tri- Allyl cyanurate, triallyl isocyanurate, triallyl trimellitate and divinyl ethers such as ethylene glycol divinyl ether, n-butanediol divinyl ether, octadecane divinyl ether, vinyl acrylate, vinyl methacrylate, allyl acrylate, methacrylic acid Vinyl and allyl esters of acrylic acid and methacrylic acid such as allyl, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol diacrylate,
Diacrylic and dimethacrylic esters of polyhydric alcohols such as triethylene glycol diacrylate and polyethylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate,
Triacrylic and trimethacrylic esters of polyhydric alcohols such as trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate, bismethacryloyloxyethylene phthalate, 1,3,5-triacryloylhexahydrotriazine and 1 , 2-butadiene homopolymer and other unsaturated bond-containing low molecular weight polymers. These are not limited to one type, and two or more types may be used simultaneously. As mentioned above, a comonomer may be used if necessary, but this should be kept within a range that does not impair the original characteristics of the vinyl chloride resin, so the vinyl chloride monomer is usually used in an amount of 100 to 55% by weight. It is desirable to use the comonomer in a range of 0 to 45% by weight. Examples of this comonomer include vinyl esters such as vinyl acetate, vinyl caproate, vinyl laurate, and vinyl stearate, olefins such as ethylene, propylene, and isobutylene, isobutyl vinyl ether, octyl vinyl ether,
Alkyl vinyl ethers such as dodecyl vinyl ether and phenyl vinyl ether, halogenated olefins such as vinylidene chloride, vinyl fluoride, propylene chloride, and vinyl bromide, ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2
Examples include acrylic acid and methacrylic esters such as -ethylhexyl methacrylate and stearyl methacrylate, and acrylic derivatives such as acrylic acid, methacrylic acid, crotonic acid, acrylonitrile, maleic anhydride, and itaconic anhydride. These are not limited to one type, and two or more types may be used simultaneously. The copolymer that will become the backbone polymer may be produced by any method such as suspension polymerization, solution polymerization, or bulk polymerization, but suspension polymerization is generally industrially and economically advantageous. It is. The method for adding the polymerizable compound is not particularly limited and various methods can be employed, but it is preferable to add it as an emulsion or a solution. Furthermore, the timing of addition to the polymerization system is not limited to the case where the compound is added and blended from the beginning, but may be added in several portions or continuously after the polymerization reaction has started. The suspension stabilizer, polymerization initiator, etc. used when carrying out the above polymerization by the suspension polymerization method may be those normally used in the polymerization of vinyl chloride monomers. For example, as a suspension stabilizer, Completely saponified or partially saponified polyvinyl alcohol, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, synthetic polymers such as maleic anhydride-vinyl acetate copolymer, starch, gelatin, etc. (These are not limited to one type, but two or more types may be used in combination). Examples of polymerization initiators include decanoyl peroxide, lauroyl peroxide,
Benzoyl peroxide, di(isopropyl)
Diacyl peroxides such as peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, acetylcyclohexylsulfonyl peroxide, peroxyesters such as tert-butyl peroxypivalate, tert-butyl peroxyneodecanate, etc. organic peroxides, and α,α′-azobisisobutyronitrile, α,α′-azobis-2,4-dimethylpaleronitrile, α,α′-azobis-4-methoxy-2,4- Examples include azo compounds such as dimethylvaleronitrile (these are not limited to one type, but two or more types may be used in combination). The method of the present invention includes adding at least one graft monomer selected from acrylic esters, methacrylic esters, and styrene monomers to the above-mentioned copolymer to be the backbone polymer, and the above-mentioned polymerizable compound. (a polymerizable compound having two or more unsaturated bonds in one molecule) is graft-polymerized to obtain the desired modified vinyl chloride-based graft copolymer. Examples of the above monomers include acrylic esters such as ethyl acrylate, isobutyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, ethyl methacrylate, butyl methacrylate,
Methacrylic acid esters such as 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, styrene, methylstyrene, α-
Examples include styrenic monomers such as methylstyrene and dichlorostyrene. By graft polymerizing such a graft monomer together with the polymerizable compound, the resulting graft copolymer has improved gelling properties in soft formulations, further improved dispersibility of gel components, and improved processability and Physical properties such as compression set are improved, and the desired excellent matte molded product can be easily obtained. The amount of the polymerizable compound used in this case is 50% by weight or less, particularly 20% by weight or less of the amount of the graft monomer used; if this amount is too large, the physical properties of the molded article will be impaired.
If this graft polymerization is not carried out, both the gelation property and the dispersibility of the gel content will become unstable due to a slight change in the gel content (the amount of crosslinking introduced), and the surface of the molded product will likely become pear-like. The graft polymerization may be carried out by a conventionally known method. For example, the copolymer (stem polymer) is produced by a suspension polymerization method, and after the polymerization is completed, the components to be grafted are added to the slurry system. A desired graft copolymer can be obtained by charging a predetermined amount and a polymerization initiator and carrying out graft polymerization. The ratio of graft component to backbone polymer is 100 parts by weight of backbone polymer to 1 part by weight of graft component.
~100 parts by weight (preferably 10-100 parts by weight,
If the amount of this graft component is less than 1 part by weight, the above-mentioned effects such as improving processability cannot be sufficiently obtained, and if it is more than 100 parts by weight, the graft copolymer obtained will lose the properties inherent to vinyl chloride resin, and it will become slippery during processing. This has the disadvantage that it may not be possible to knead it because of its too high properties. The modified vinyl chloride-based graft copolymer obtained by the method of the present invention has almost the same processability as general vinyl chloride resin, and has excellent compression set, improved creep resistance, and a matte appearance. It has the feature of giving soft molded products, and the plasticizers used to obtain such soft molded products include alkyl aromatic polybasic acids such as dibutyl phthalate, dioctyl phthalate, and butylbenzyl phthalate. Examples include alkyl esters of aliphatic polybasic acids such as esters, dioctyl adipate, dioctyl azelate, and dioctyl sebacate, and phosphoric acid alkyl esters such as tricresyl phosphate. In addition, lead-based stabilizers such as tribasic lead sulfate, tin-based stabilizers such as dibutyltin malate, heat stabilizers exemplified by metal soaps such as zinc stearate and calcium stearate, carbon black, calcium carbonate, and titanium oxide. , talc, asbestos, aluminum hydroxide, magnesium hydroxide, and other fillers;
It is optional to add pigments such as color carbon black, chrome yellow, titanium oxide, phthalocyanine green, etc., as well as antistatic agents, dropless agents, ultraviolet absorbers, and the like. As described above, the modified vinyl chloride graft copolymer according to the present invention can be molded by
It can be blended, kneaded and molded in the same steps as conventional vinyl chloride resins, and may be supplied in either pellet or powder form. Furthermore, the molding conditions are no different from those of conventional vinyl chloride resins, and the above-mentioned excellent molded products can be easily obtained. Next, specific examples will be given. Example 1 The following components were charged into a stainless steel polymerization vessel having an internal volume of 50 mm, and a polymerization reaction was carried out at 50° C. for 10 hours. Pure water 30Kg Vinyl chloride monomer comonomer AKg BKg Total 15Kg Polymerizable compound Cg Partially saponified polyvinyl alcohol 20g Di-2-ethylhexyl peroxycarbonate
7.5g (type of comonomer and polymerizable compound, A,
(The amounts of B and C are listed in the table) Next, the graft monomer, polymerizable compound, and lauryl peroxide were added in the following proportions to a predetermined amount of the copolymer slurry obtained by the above polymerization. , a graft polymerization reaction was carried out at 80°C for 4 hours. Copolymer slurry 12Kg as solid content Graft monomer DKg Polymerizable compound Part E lauryl peroxide 0.1 part (type of graft monomer and polymerizable compound,
The amounts of D and E are listed in the table, however, part E of the polymerizable compound and 0.1 part of lauryl peroxide are parts per 100 parts by weight of the graft monomer.) After graft polymerization as described above. After washing with water and dehydrating and drying, vinyl chloride-based graft copolymers having gel contents (wt%) as shown in the table were obtained. [Measurement method for gel content in copolymer] 1.00 g of sample was added to 100 ml of tetrahydrofuran (THF), dissolved by shaking at the boiling point of THF for 60 minutes, undissolved content was centrifuged, and the amount was calculated from its dry weight. Dioctyl phthalate was added to 100 parts by weight of the vinyl chloride graft copolymer produced as described above.
80 parts by weight, 2 parts by weight of calcium stearate, and 5 parts by weight of epoxidized soybean oil were blended and kneaded for 10 minutes after being rolled at 160°C using a 3-inch roll.
At this time, the roll winding time (seconds) and the state of the sheet surface (rolled sheet) wound around the roll were observed. [Measurement of roll winding time (seconds)] The time (seconds) from when the mixture was put on the roll to when the mixture appeared to be gelled on the roll surface was measured using a stopwatch. Next, add carbon black to the above formulation.
The mixture to which 0.2 parts by weight was added was extruded into a sheet using a 20 mm diameter extractor, and the surface condition of this sheet (extrusion molded product) was observed. On the other hand, preheat the roll sheet to 185℃ for 7 minutes, 30 minutes.
Compression set was measured for a product press-formed under Kg/cm ² pressure for 4 minutes. [Measurement of compression set] Based on JIS K 6301, measurement was performed under the conditions of 25% compression at 70°C for 22 hours. The results were as shown in the table. As is clear from these results, in the case of the present invention, moldability, matte state, and compression set are improved. [Abbreviations used in the table] 1 Comonomer VAc: Vinyl acetate AEH: 2-ethylhexyl acrylate 2 Polymerizable compound DAP: Diallyl phthalate DAM: Diallyl maleate DAI: Diallyl itaconate BHP: 1,2-butadiene homopolymer PEA : Polyethylene glycol diacrylate MAB: Vinyl methacrylate 3 Graft monomer AEH: 2-ethylhexyl acrylate MST: α-methylstyrene ST: Styrene MAB: Butyl methacrylate

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Claims (1)

[Scope of Claims] 1. A vinyl chloride monomer or a mixture of monomers copolymerizable with it, and 0.01 to 2% by weight of this polymerizable monomer having two or more unsaturated bonds in one molecule. 100 parts by weight of copolymer with compound, acrylic ester, methacrylic ester,
At least one type of monomer selected from styrene monomers, and 2 to 50% by weight or less of this monomer in one molecule.
Graft polymerizing 1 to 100 parts by weight of a mixture with a polymerizable compound having 1 or more unsaturated bonds,
A method for producing a characterized modified vinyl chloride graft copolymer.