JPH038383B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin composition that is excellent in heat resistance, light resistance, and cold resistance, and has good resistance to permanent set by compression and tension, processability, and mechanical strength. Soft vinyl chloride resins containing plasticity have been widely used as materials for hoses, gaskets, leather, films, wire coatings, and the like. However, this soft vinyl chloride resin has the disadvantage that its shape retention at high temperatures and permanent deformation resistance are significantly lower than that of vulcanized rubber. As an improvement method, for example, if a high polymerization degree vinyl chloride resin with an average polymerization degree of 2500 to 4000 is used, the compression set (JISK-6301, 70℃ x 22Hr) will be 60% higher than that of conventional soft vinyl chloride resin. ~70% versus 50%
However, it is unsuitable as a material for hoses, gaskets, packings, etc., which require even lower permanent set characteristics. For this reason, even if a vinyl chloride resin with a higher degree of polymerization with an average degree of polymerization of 4,000 to 10,000 or more than 10,000 is used, not only will it not be possible to obtain a composition with the expected low permanent set,
Productivity during the production of vinyl chloride resin is low, and
This is not preferable since it also has the disadvantage of deteriorating molding processability. It is also introduced in "Basic properties of PVC formulations containing nitrile rubber powder (1), (2), (3)" (Polymer Digest, March, May, June 1980 issue). Partially crosslinked nitrile rubber, e.g. Chemi Gum
When N8B-1A2 (manufactured by Gutdeyer Co., Ltd.) is blended with vinyl chloride resin and plasticity, compression set properties are improved, but heat resistance, light resistance, etc. due to the butadiene monomer unit in nitrile rubber are improved. The disadvantage is that the performance is lower than that of systems that do not contain these nitrile rubbers. Reducing the butadiene moiety in nitrile rubber, which is the cause of this, will inevitably increase the acrylonitrile moiety, raising the glass transition temperature of the crosslinked rubbery polymer and increasing the This is not preferable because it reduces the cold resistance of the product. In order to improve these various points, as a result of intensive studies, we have developed a monomer that reduces the butadiene moiety and instead increases the acrylonitrile content, giving a homopolymer with a glass transition temperature lower than that of polyacrylonitrile. That is, 30 to 200 parts by weight of a crosslinked rubbery polymer obtained by copolymerizing an alkyl (meth)acrylate and/or alkoxyalkyl (meth)acrylate with a specific crosslinking monomer. A composition containing 100 parts by weight of a vinyl chloride resin with an average degree of polymerization of 2000 or more and 20 to 200 parts by weight of plasticity improves heat resistance, light resistance, and cold resistance, has small permanent deformation due to compression and tension, and has good processability. It was discovered that a composition with well-balanced mechanical strengths can be provided, and the present invention was achieved. That is, the present invention includes (A) 100 parts by weight of a vinyl chloride resin having an average degree of polymerization of 2,000 or more, (B) 5 to 65 parts by weight of butadiene and/or isoprene, and 10 parts by weight of acrylonitrile as monomer units constituting the copolymer. ~
50% by weight, alkyl (meth)acrylate and/or alkoxyalkyl (meth)acrylate 5 to 80% by weight, and 0.1 to 5.0% by weight of a crosslinking monomer of the following general formula (), with a methyl ethyl ketone insoluble content of 20 to 95% by weight. 30 to 200 parts by weight of a certain crosslinked rubbery polymer; [In the formula, R ₁ represents H or a methyl group, R is -C ₆ H ₄ -, or

[Formula] (n is an integer from 1 to 4, R ₂ is -CH ₂ CH ₂ -, -
CH ₂ CH ₂ CH ₂ −, CH ₂ CH ₂ CH ₂ CH ₂ −, or

Represents [formula] ] (C) Plasticity The main component is 20 to 200 parts by weight, has excellent heat resistance, light resistance, and cold resistance, has extremely low permanent deformation due to compression and tension, and has excellent workability and mechanical properties. The present invention is characterized by providing a new vinyl chloride-based resin composition that is well-balanced in terms of strength and strength. Hereinafter, the constituent elements of the present invention will be explained separately. First, the crosslinked rubbery polymer used in the present invention can be obtained by a conventional emulsion polymerization recipe. As the polymerization initiator, conventional radical initiators such as peroxides, redox compounds, persulfates and azo compounds can be used. Anionic, cationic, nonionic or amphoteric surfactants are used as the emulsifier. Typical examples of molecular weight modifiers include mercaptans such as secondary dodecyl mercaptan and normal dodecyl mercaptan. Examples of alkyl (meth)acrylates include:
Methyl, ethyl, propyl, butyl, hexyl,
Examples include octyl acrylate or methacrylate. Particularly preferred is butyl acrylate. Examples of alkoxyalkyl (meth)acrylates include methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl acrylate or methacrylate. One or more of these may be used. As a crosslinking monomer, 1 general formula [In the formula, R ₁ represents H or a methyl group, R is -C ₆ H ₄ -, or

[Formula] (n is an integer from 1 to 4, R ₂ is -CH ₂ CH ₂ -, -
CH ₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ CH ₂ −, or

[Representing the formula])], specifically, divinylbenzene, diisopropenylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate Among them, use of divinylbenzene is particularly preferred. Polymerization is carried out at 0-50°C in an oxygen-free reactor. Monomers, emulsifiers, initiators, molecular weight regulators, and other additives may be added in their entirety before the start of the reaction, or may be added in arbitrary portions after the start of the reaction, or may be adjusted during the reaction by adjusting the temperature, stirring, etc. Conditions can be changed arbitrarily. The polymerization method may be either continuous or batchwise. The Mooney viscosity of the crosslinked rubbery polymer thus obtained is not particularly limited, but is ML ₁₊₄ (100
℃) from 20 to 120 is desirable. More preferably 30
It is 80 from Further, it is necessary that the methyl ethyl ketone insoluble content of the crosslinked rubbery polymer is 20% to 95%. When it is less than 20%, workability is poor and compression set is not improved, and when it exceeds 95%, elongation at break decreases. Quantification of methyl ethyl ketone insoluble content is performed using 1 g of sample.
50 c.c. of methyl ethyl ketone was added to the sample, left at room temperature for 24 hours, and then shaken for 1 hour.The sample was centrifuged at 10,000 rpm for 90 minutes, and the insoluble matter was vacuum-dried. was calculated from the value divided by the sample weight. What is particularly important about the crosslinked rubbery polymer in the composition of the present invention is that the crosslinking monomer is a component of the copolymer.
It should be contained in an amount of 0.1 to 5.0% by weight. Even if the methyl ethyl ketone insoluble content falls within the numerical range of the present invention, a product with good processability cannot be obtained if the crosslinking monomer content is less than 0.1% by weight. Moreover, if the crosslinking monomer exceeds 5.0% by weight, the performance as a rubber cannot be obtained. In order to balance various physical properties, it is effective to mix the crosslinked rubber-like polymer with a proportion of 30 to 200 parts by weight per 100 parts by weight of vinyl chloride resin with an average degree of polymerization of 2000 or more, especially 40 to 120 parts by weight. Parts by weight are preferred. The vinyl chloride resin used in the present invention is characterized by an average degree of polymerization of 2000 or more. As for the manufacturing method, any manufacturing method such as bulk polymerization, suspension polymerization, emulsion polymerization, or solution polymerization may be adopted, but a powdered vinyl chloride resin produced by suspension polymerization is particularly suitable. If the average degree of polymerization is less than 2000, for example, if a vinyl chloride resin with a grade of 1100, which is one of the so-called general-purpose soft PVCs, is used, the compression set of the blended composition,
The average degree of polymerization was
Limited to 2000 or more. In addition to the homopolymer of vinyl chloride, the vinyl chloride resin having an average degree of polymerization of 2000 or more is one of the following types of vinyl chloride that can be copolymerized with a small amount of vinyl chloride.
Alternatively, it may be a polymer of a mixture with more monomers. Monomers that can be copolymerized with vinyl chloride include α-olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl stearate, vinyl ethers such as methyl vinyl ether and lauryl vinyl ether, methyl acrylate, and methacrylate. Acrylic acid and methacrylic acid esters such as methyl acid, amides such as methacrylamide and acrylonitrile, nitriles, styrenes such as styrene and α-methylstyrene, and polyfunctional monomers such as diallylphthalate and ethylene glycol dimethacrylate. It includes the body. Plasticity is not particularly limited, and as with conventional soft vinyl chloride resins, examples include phthalic acid esters such as di-2-ethylhexyl phthalate and dibutyl phthalate, and di-2-ethylhexyl phthalate. Adipic acid esters such as ethylhexyl adipate, sebacic acid esters such as dibutyl sebacate, trimellitic acid ester acids such as tri-2-ethylhexyl trimellitate, and epoxy compounds such as epoxidized soybean oil are used. The amount added is not particularly limited, but it is preferably 20 to 200 parts by weight per 100 parts by weight of the vinyl chloride resin, and it is based on the plasticization efficiency of the crosslinked rubbery polymer mentioned above and the hardness required by the product. , use an appropriate amount depending on flexibility, physical properties, and moldability. It is also possible to add other polymeric auxiliaries, such as ethylene-vinyl acetate copolymer, acrylic resin, chlorinated polyethylene, polyurethane, chlorosulfonated polyethylene, acrylonitrile-butadiene copolymer, etc. . It goes without saying that in addition to the above, heat stabilizers, fillers, lubricants, foaming agents, flame retardants, pigments, etc. may be added to the vinyl chloride resin composition of the present invention, as necessary. . The mixing and molding of three components of a vinyl chloride resin, a crosslinked rubber-like polymer, and a plasticizer to produce the vinyl chloride resin composition of the present invention are as follows:
Any method may be used as long as the ingredients are substantially uniformly dispersed, mixed, and kneaded. For example, dry blending is performed using a Henschel mixer, ribbon blender, etc., and this dry blend powder is directly molded. Alternatively, the mixture may be melt-kneaded using an extruder, rolls, etc., then pelletized, and then molded. The molding method may be extrusion molding, injection molding, blow molding, calendar molding, vacuum molding, or the like, depending on the desired shape and properties of production. Fields of application of the present invention include hoses, gaskets, leather, films, electric wire covering materials, etc., and it is particularly preferably used for hoses and gaskets. In order to further facilitate understanding of the present invention, the present invention will be specifically explained below using experimental examples, examples, and comparative examples, but the present invention is not limited by these. Experimental Example A polymerization reaction was carried out at 10°C in an autoclave with an internal volume of 20 using the monomers and polymerization agents shown below. Butadiene 33.6 parts by weight Acrylonitrile 26 parts by weight Butyl acrylate 40 parts by weight Divinylbenzene 0.4 parts by weight Water 220 parts by weight Sodium dodecylbenzenesulfonate 35 parts by weight Tertiary dodecyl mercaptan 0.15 parts by weight Potassium persulfate 0.27 parts by weight Cyanoethylated diethanolamine 0.15 parts by weight Part Potassium Hydroxide 0.10 parts by weight After the polymerization rate reached 90%, 0.2 parts by weight of hydroxylamine sulfate per 100 parts by weight of monomer was added to stop the polymerization. Then, after heating and removing residual monomers by steam distillation, the rubber solids are
2 parts by weight of an anti-aging alkylated phenol were added per 100 parts by weight, and the latex was coagulated with an aqueous calcium chloride solution. After washing the obtained coagulated material with water, it was dried at 50° C. under reduced pressure to prepare a sample for evaluation. (Table 1, Experimental Example 1) Table 1 summarizes copolymers prepared using the same recipe by varying the amount of monomer charged and the amount of tertiary dodecyl mercaptan charged. (Table 1, Experimental Examples 2 to 8)
Examples 1 to 9, Comparative Examples 1 to 10 In a Henschel super mixer with a jacket temperature of 95°C, 100 parts by weight of a vinyl chloride resin having a predetermined average degree of polymerization shown in Table 2 and a barium and zinc fatty acid salt composite stabilizer were added. Add 3 parts by weight until the temperature of the contents reaches
Stir and mix at high speed until the temperature reaches 60°C or higher, and add a predetermined amount of di-2-ethylhexyl phthalate (hereinafter referred to as DEHP) shown in Table 2. The temperature of the contents
When the temperature reached 120°C, a predetermined amount of the crosslinked rubber polymer shown in Table 2 (Experimental Examples 1 to 8) was added, stirred for about 5 minutes, and then taken out. Each of the vinyl chloride resin compositions taken out was kneaded using two rolls with a surface temperature of 160°C for 10 minutes after the composition was wound around the rolls. Each test piece was prepared by press-molding this roll sheet, and subjected to each test of tensile test, heat resistance, light resistance, cold resistance, compression set, and permanent elongation. The results are shown in Table 2. The test methods and evaluation methods in the table were as follows. (1) Roll processability Good roll cohesion and smooth surface condition
…〇 Roll cohesion is somewhat poor, and the surface condition is slightly uneven …△ Roll cohesion is poor, and a good sheet cannot be obtained …× (2) Compression set JIS K 6301, 70℃×22Hr (3) Permanent Elongation JIS K 6301, elongation rate 100% (4) Normal tensile strength, elongation JIS K 6273 (5) Heat resistance Determine the tensile strength after heat aging for 168 hours at 120°C in a gear oven, and change from the normal tensile strength. The ratio is within ±5%...◎ -5 to -10, +5 to +10%...○ -10 to -20, +10 to +20%...△ Greater than ±20%...It was marked as ×. (6) Light resistance A JIS No. 3 dumbbell was set in a fade meter using a mercury lamp (black panel temperature 63℃), exposed to light for 15 hours, and then subjected to a tensile test. The change rate from the normal tensile strength was within ±15%... 〇±15% or more…marked as △. (7) Cold resistance (embrittlement temperature) JIS K 6723 As is clear from Table 2, Examples 1 to 2 of the present invention
It can be seen that composition No. 9 has good roll processability, low compression set and low permanent elongation, and has a good balance of heat resistance, light resistance, cold resistance, and mechanical strength.

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Claims (1)

[Claims] 1 (A) Vinyl chloride resin with an average degree of polymerization of 2000 or more
100 parts by weight, and (B) as copolymer units, 5-65% by weight of butadiene and/or isoprene, 10-50% by weight of acrylonitrile, and 5-80% by weight of alkyl (meth)acrylate and/or alkoxyalkyl (meth)acrylate. %, and 30 to 200 parts by weight of a crosslinked rubbery polymer consisting of 0.1 to 5.0% by weight of a crosslinking monomer of the following general formula () and 20 to 95% by weight of a methyl ethyl ketone insoluble content, and (C) 20 to 200 parts by weight of a plasticizer. A vinyl chloride resin composition having parts as main components. [In the formula, R ₁ represents H or a methyl group, R is -C ₆ H ₄ -, or [Formula] (n is an integer of 1 to 4, R ₂ is -CH ₂ CH ₂ -, -
CH ₂ CH ₂ CH ₂ −, CH ₂ CH ₂ CH ₂ CH ₂ −, or [Formula]]