JP3379185B2 - Oil resistant material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl chloride resin (hereinafter referred to as "PVC"), a core-shell type latex rubber and a polyvinyl chloride resin containing a high molecular weight plasticizer. Made of resin composition, excellent in compression set and material strength, good oil resistance and heat resistance, suitable for various packing materials for sealing around fuel oil, lubricating oil, hose and tube, and boot materials The present invention relates to a rubber molded article material. 2. Description of the Related Art When an appropriate amount of a plasticizer represented by DOP (di-2-ethylhexyl phthalate) is mixed with PVC, a rubber-like molded article having excellent flexibility and elasticity can be obtained. Widely used for hoses, tubes, sealing materials, pads, boots, etc. However, this composition does not have sufficient rubber elastic properties such as compression set, and when used as a rubber molding material for automobiles, it has a small change in elastic modulus at a use temperature and has improved heat resistance. When a product is required and used for a fuel hose, a lubricating oil hose or an oil sealing packing, a material having further improved oil resistance is desired. It is generally known that blending PVC with a crosslinked or partially crosslinked NBR (acrylonitrile-butadiene rubber) having good compatibility with PVC can improve the compression set. At present, distortion is still not sufficient, and further improvement in oil resistance is desired at present. SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber molded material having excellent compression set and material strength, and excellent oil resistance and heat resistance. [0005] In view of the above-mentioned situation, the present inventors have formulated a resin composition comprising a mixture of PVC and a high-molecular-weight plasticizer mixed with a core-shell type latex rubber. As a result of intensive studies, the present invention has been completed. That is, in the present invention, the specific core-shell type latex rubber is 20 to 200 parts by weight based on 100 parts by weight of PVC, and the specific plasticizer is 20 to 200 parts by weight of the total weight of PVC and the core-shell type latex rubber. It is an oil resistant material obtained by molding a PVC composition containing up to 200 parts by weight. The details of the present invention are described below. [0006] The PVC used in the present invention is a random copolymer or a block copolymer of at least one of vinyl chloride homopolymer resin, chlorinated vinyl chloride resin, and all monomers copolymerizable with vinyl chloride monomer. In the vinyl chloride copolymer resin obtained by copolymerization, monomers that can be copolymerized include ethylene, vinyl acetate, vinylidene chloride, methyl methacrylate, methacrylates such as ethyl methacrylate,
Acrylic esters such as methyl acrylate and ethyl acrylate; alkylmaleimides such as methylmaleimide and ethylmaleimide; maleimide monomers such as phenylmaleimide; styrene monomers such as styrene and α-methylstyrene; and acrylonitrile. No. It is also possible to use a single resin or a mixture of two or more of the above resins. The structure of the core-shell type latex rubber used in the present invention is mainly composed of butyl acrylate as a main component.
A core material cross-linked with a monomer having two or more reactive double bonds, for example, an aromatic divinyl monomer such as divinylbenzene, or a compound such as butylene glycol diacrylate, and the surface of the core material; Partially styrene-acrylonitrile with excellent compatibility with polyvinyl chloride resin
It is a core-shell type latex rubber composed of a shell material composed of a ril copolymer . This core material achieves the object of the present invention if crosslinked regardless of the degree of crosslinking, and the acrylic rubber constituting the core material has oil resistance,
Because of its excellent heat resistance, it is preferable for the intended use of the present invention. The core-shell type latex rubber used in the present invention can be prepared in a multistage manner by emulsification and seed polymerization, whereby the average particle diameter of the core material portion and the average thickness of the shell material can be uniformly adjusted. In the present invention, a core material having an average particle diameter of 0.05 to 5 μm is used, and more preferably 0.15 to 1 μm. If the average particle diameter is less than 0.05 μm, it is difficult to develop sufficient rubber elasticity, that is, compression set, and if it is more than 5 μm, the material strength may be impaired. Further, those having a large average particle diameter are effective in improving the compression set when the same amount is added. The amount of the core-shell type latex rubber added to the PVC composition used in the present invention is PVC 1
The amount is 20 to 200 parts by weight, more preferably 40 to 150 parts by weight, per 100 parts by weight. When the amount is less than 20 parts by weight, not only the rubber elasticity, that is, the compression set cannot be improved, but also sufficient oil resistance and heat resistance cannot be obtained. When the amount exceeds 200 parts by weight, the compression set is improved. However, the balance of other physical properties, such as material strength, is impaired. Further, the chemical composition of the shell material resin of the core-shell type latex rubber used in the present invention is based on a styrene-acrylonitrile copolymer having excellent compatibility with PVC.
It becomes . The term “compatibility” used herein refers to an appropriate mixing method of two kinds of polymers (melt blending, solution blending).
And refers to a mixed state where the glass transition temperature (Tg) in differential scanning calorimetry (DSC) or dynamic viscoelasticity measurement is unity. This compatibility is reflected in the material strength through the interfacial adhesion between the two phases (layers), and the interfacial adhesion between PVC and the core-shell type latex rubber can be determined based on the peel strength of the laminate. . That is, PVC 2
A peel test is performed on a laminate of a 2 mm-thick sheet of a mm-thick sheet (containing 100 parts by weight of a polyester polymer plasticizer as a plasticizer with respect to 100 parts by weight of PVC) and a 2 mm-thick sheet of core-shell type latex rubber, PVC
Peel strength when the shell material and the shell material are compatible with each other is 500 g / cm
Or more, more preferably 800 g
/ Cm or more. Incidentally shell material is a styrene - When the acrylonitrile copolymer is 1100 g / cm. The thickness of the shell material of the core-shell type latex rubber used in the present invention is 5 to 50 nm, more preferably 10 to 30 nm. That is, if the shell thickness is less than 5 nm, the composition has excellent flexibility as rubber, but the PVC and the resin constituting the shell material or the entanglement between the shell materials is not sufficient, and the material strength is impaired. On the other hand, the material strength and the compression set can be improved by increasing the thickness of the shell material, but when the thickness is increased more than necessary, the hardness of the PVC composition becomes extremely high although the material strength is excellent, and the molded product is hardly formed. It becomes resin-like and impairs flexibility as a thermoplastic elastomer. Note that the shell thickness and the entanglement here have a close relationship, and when the shell thickness is the same, the smaller the molecular weight between entanglement points, the easier it is to entangle. In the present invention, the molecular weight between entanglement points is preferably 20,000 or less. , More preferably 15,000 or less. As the plasticizer used in the present invention, a high molecular weight plasticizer having a number average molecular weight of 1,000 or more and capable of efficiently plasticizing PVC is used. Examples of such high molecular weight plasticizers include adipic acid-based, sebacic acid-based, and phthalic acid-based polyester high-molecular-weight plasticizers and epoxy-based high-molecular-weight plasticizers. This number average molecular weight is 100
If it is less than 0, sufficient oil resistance cannot be realized. If the molecular weight is 1000 or more, different kinds of high molecular weight plasticizers can be used in combination. If necessary, di-2-ethylhexyl phthalate (D
OP) and other low-molecular-weight plasticizers such as phthalic acid plasticizers, trimellitic acid plasticizers, and phosphate ester plasticizers. However, in that case, the mixing ratio of the high molecular weight plasticizer and the low molecular weight plasticizer is 10% by weight.
/ 0/5/5, and when the mixing ratio of the low molecular weight plasticizer exceeds 50%, sufficient oil resistance may not be obtained. The amount of the plasticizer used is 20 parts by weight based on 100 parts by weight of the total weight of PVC and the core-shell type latex rubber.
To 200 parts by weight, preferably 30 to 100 parts by weight, more preferably 40 to 70 parts by weight. That is, when the amount is less than 20 parts by weight, the obtained material has excellent oil resistance, but lacks flexibility as a thermoplastic elastomer. On the other hand, when the amount exceeds 200 parts by weight, the obtained material has excellent flexibility, low viscosity, and excellent compression set. The material strength is remarkably impaired, causing a problem of bleeding of the plasticizer such as stickiness of the surface. The PVC composition used in the present invention includes a thermoplastic resin having excellent compatibility with PVC to such an extent that its performance is not extremely deteriorated, calcium carbonate, talc, clay, carbon black and the like which are usually added to PVC. Various additives such as inorganic fillers such as metal oxides, flame retardants such as antimony trioxide and zinc borate, heat stabilizers such as barium stearate and zinc stearate, antioxidants, and ultraviolet absorbers Agents can be added as needed. The oil-resistant material of the present invention is obtained by molding the above-mentioned PVC composition. And the kneading and molding method for this molding is not particularly limited,
General kneading and forming methods can be used.
That is, a PVC composition comprising a PVC, a plasticizer, and a core-shell type latex rubber is heated and melt-mixed under a shearing force by a roll kneader, a Banbury kneader, a single-screw or twin-screw extruder, or the like. And can be easily kneaded. Further, the kneaded product of the PVC composition can be easily heated and melt-molded using a usual molding method, that is, a press molding machine, an extrusion molding machine, an injection molding machine or the like. The above-mentioned materials of the present invention include various oil-resistant fuel oils, various packing materials for sealing around lubricating oils,
It can be widely used for hose and tube materials and boot materials. EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples. Example 1 100 parts by weight of ethylene-vinyl chloride copolymer (Ryuron E-2800, manufactured by Tosoh Corporation) as PVC, 2 parts by weight of barium stearate, 1 part by weight of zinc stearate as a stabilizer, high molecular weight 100 parts by weight of a plasticizer (Adekaizer PN280 manufactured by Asahi Denka Co., Ltd.) based on PVC, core-shell latex (Staphyroid 1413 manufactured by Takeda Pharmaceutical Co., Ltd., average particle diameter 0.6 μm, shell composition acrylonitrile ( AN) -styrene copolymer (A
N content = 25 wt%, molecular weight between entanglement points 9200),
70 parts by weight of a shell thickness of 10 to 15 nm) were melt-kneaded at 150 ° C. for 15 minutes using an 8-inch roll.
The obtained mixed sample was press-formed and subjected to each material test.
Table 1 shows the test results. Example 2 A mixture of the plasticizer used in Example 1 and di-2-ethylhexyl phthalate (DOP) (mixing ratio (weight ratio) is 5/5) was used as the plasticizer. A sample was obtained and evaluated in the same manner as in Example 1 except for the presence of the sample. Table 1 shows the results. Comparative Example 1 100 parts by weight of an ethylene-vinyl chloride copolymer (Ryuron E-2800, manufactured by Tosoh Corporation) as PVC, 2 parts by weight of barium stearate, 1 part by weight of zinc stearate as a stabilizer, plasticizer 100 parts by weight, based on PVC, of the high molecular weight plasticizer used in Example 1 and partially cross-linked NBR (PNC-38 manufactured by Nippon Synthetic Rubber Co., Ltd., acrylonitrile content 40%, particle diameter 0.05 to 0.1 μm) 7
0 parts by weight were blended, and molding and material tests were performed as in Example 1. Table 1 shows the results. Hereinafter, the method of the obtained material test is shown. (Evaluation of Compression Set) A compression set test was performed in accordance with JIS K6301 (70 ° C., 22 hours). (Evaluation of Material Strength) The tensile strength was evaluated in accordance with JIS K6723. (Evaluation of Oil Resistance) According to JIS K6301, the weight change rate after immersion in No. 1 oil, No. 3 oil and engine oil kept at 100 ° C. for 70 hours was evaluated. (Evaluation of heat resistance) Evaluation was made based on JIS K6723 by a heat deformation ratio. (Evaluation of Cold Resistance) The embrittlement temperature was evaluated according to JIS K6301. [ Table 1] As described above, the material of the present invention is excellent in compression set and tensile strength, and can be used as a material for a rubber molded product having good oil resistance and heat resistance.

Claims (1)

(57) [Claim 1] 20 to 200 parts by weight of a core-shell type latex rubber described in (Title 1), based on 100 parts by weight of a polyvinyl chloride resin, (Title 2) Oil-resistant material obtained by molding a polyvinyl chloride resin composition containing the plasticizer described in 20 to 20 to 200 parts by weight based on 100 parts by weight of the total weight of the polyvinyl chloride resin and the core-shell type latex rubber . (Title 1) The average particle diameter of the core material portion is 0.05 to 5 μm, the core material is a crosslinked polybutyl acrylate, and the shell material is styrene-
A core-shell type latex rubber composed of an acrylonitrile copolymer and having a thickness of 5 to 50 nm. (Title 2) A polyester high molecular weight plasticizer having a molecular weight of 1000 or more and / or an epoxy high molecular weight plasticizer having a molecular weight of 1000 or more .