JPS6358172B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is made from an α,β-unsaturated nitrile-conjugated diene-fluoroalkyl (meth)acrylate terpolymer (hereinafter abbreviated as NBF) and a vinyl chloride resin (hereinafter abbreviated as PVC). Become,
The present invention relates to a rubber composition that has excellent sour gasoline resistance and alcohol-containing gasoline resistance, and has an excellent balance of physical properties in normal state physical properties, cold resistance, compression set, etc. In recent years, automobile exhaust gas regulations have become stricter, and each automobile manufacturer has taken their own measures, but in addition, sour gasoline (gasoline that is oxidized at high temperatures and contains peroxide) while driving. .Ners―asian:
Described in Rubber and Plastics News June 26 (1978). ) has occurred and is becoming a new problem. Furthermore, due to the tight global supply and demand for crude oil, attempts have been made to mix alcohol with gasoline. Conventionally, butadiene-acrylonitrile rubber (NBR) has been generally used as a rubber material for fuel, but it is difficult for such a material to withstand the above-mentioned sour gasoline and alcohol-containing gasoline. As a method to improve this, it is known to improve sour gasoline resistance by using a blend of butadiene-acrylonitrile rubber (NBR) and vinyl chloride (Japanese Patent Application Laid-Open No. 89338/1989). In order to improve resistance to sour gasoline and alcohol-containing gasoline, normal physical properties, cold resistance, compression set, etc. are significantly sacrificed, and improvement of these drawbacks is desired. In addition, because fluorocarbon rubber has excellent resistance to sour gasoline and alcohol-containing gasoline (Japan Rubber Association Tokai Branch Introduction Lecture Material, "Recent Requests from the Automotive Industry for Fluorocarbon Rubber 'Viton'") Showa Neoprene
Tsuyoshi Sugiki Co., Ltd.) has been in the spotlight as a rubber material for fuel, but fluorocarbon rubber cannot be vulcanized with sulfur, and its physical properties are poor, making it difficult to handle.
It is also very expensive and has no versatility as a fuel rubber material. The present inventors have found that they have excellent sour gasoline resistance and alcohol-containing gasoline resistance, are sulfur vulcanizable, and can be easily processed using conventional molding equipment and techniques.
Furthermore, the terpolymer NBF has already been discovered as a new rubber material with an excellent balance of physical properties such as normal physical properties, cold resistance, and compression set (Japanese Patent Application Laid-Open No. 109814/1983). As a result of further various studies using the rubber material, the present inventors found that NBF
A composition obtained by mixing NBR with PVC has excellent sour gasoline resistance and alcohol-containing gasoline resistance as a fuel rubber material, which is better than that improved by mixing NBR with PVC, and It has a good balance in normal physical properties and compression set, and what is even more surprising is the discovery that tensile strength and cold resistance can be greatly improved by mixing NBF and PVC. This invention has been achieved. That is, the present invention provides α,β-unsaturated nitriles 15 to
97 to 40 parts by weight of a ternary copolymer (NBF) consisting of 60 mol%, 10 to 75 mol% of conjugated diene, 2 to 55 mol% of fluoroalkyl (meth)acrylate, and 3 to 40 parts by weight of vinyl chloride resin (PVC). The present invention relates to a rubber composition containing 60 parts by weight, which has excellent sour gasoline resistance and alcohol-containing gasoline resistance, and has good normal physical properties, cold resistance, and compression set in a well-balanced manner. α of the terpolymer (NBF) used in the present invention,
Specific examples of β-unsaturated nitriles include acrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile,
Among them, acrylonitrile is particularly preferred. As the conjugated diene, butadiene-1, 3, 2
-Chlorobutadiene-1,3,2-fluorobutadiene-1,3,2-methylbutadiene-1,
3, among others, butadiene-
1 and 3 are preferred. The fluoroalkyl (meth)acrylate is preferably a fluorine-containing alkyl group whose alkyl group has 1 to 20 carbon atoms, particularly preferably 1 to 15 carbon atoms, and specific examples include 1,1-dihydroperfluoroethyl ( meth)acrylate, 1,1-dihydroperfluoropropyl (meth)acrylate,
1,1,5-trihydroperfluorohexyl (meth)acrylate, 1,1,2,2-tetrahydroperfluoropropyl (meth)acrylate, 1,1,7-trihydroperfluoroheptyl (meth)acrylate, 1,1- Dihydroperfluorooctyl (meth)acrylate, 1,1
-dihydroperfluorodecyl (meth)acrylate, among others, 1,1-dihydroperfluoroethyl (meth)acrylate and 1,1-dihydroperfluoropropyl (meth)acrylate are particularly preferred. The composition ratio of each component of the terpolymer of the present invention is:
Based on the total number of moles of the three components, α,β-unsaturated nitrile 15 to 60 mol% (preferably 20 to 55 mol%, more preferably 25 to 50 mol%), conjugated diene 10 to
75 mol% (preferably 20 to 65 mol%, more preferably 35 to 65 mol%), 2 to 55 mol% of fluoroalkyl (meth)acrylate (preferably 4 to 45 mol%, more preferably 5 to 30 mol%) %). If the proportion of α,β-unsaturated nitrile in the terpolymer is less than 15 mol%, gasoline resistance will be poor, and if it exceeds 60 mol%, it will become resinous and have poor processability. If the ratio of the conjugated diene is less than 10 mol %, the rubber elasticity will be poor and the normal physical properties of the polymer will be poor. In addition, when the ratio of conjugated diene exceeds 75 mol%, gasoline resistance
Poor resistance to alcohol and gasoline. If the proportion of fluoroalkyl (meth)acrylate is less than 2 mol%, there will be no effect on sour gasoline resistance and alcohol-containing gasoline resistance, and if it exceeds 55 mol%, cold resistance will be poor. The above terpolymer can be produced by conventional emulsion polymerization. The PVC used in the present invention is polyvinyl chloride and a copolymer of vinyl chloride and vinyl acetate, ethylene, propylene, butadiene, styrene, etc. (usually the vinyl chloride content is 60 mol% or more, preferably 80 mol% or more).
mol% or more). Although there are no particular limitations, those having a degree of polymerization of 500 to 2,000 are preferably used. The amount of PVC is terpolymer (NBF)
It is 3 to 60 parts by weight compared to 97 to 40 parts by weight. If it is less than 3 parts by weight, no effect will be seen, and if it exceeds 60 parts by weight, the rubbery properties will deteriorate. The method of mixing these compositions is not particularly limited, but the following method can be used. (a) Roll terpolymer (NBF) and PVC,
A method of mixing using a mixer such as a Banbury mixer or an intermixer; (b) A method of mixing the ternary copolymer (NBF) and PVC in the form of a latex or suspension, and then coagulating and co-precipitating the mixture. , or (c), a method that uses (a) and (b) together. The terpolymer rubber composition obtained in the present invention may be compounded with conventional compounding chemicals such as reinforcing agents, fillers, plasticizers, softeners, vulcanizing agents, stabilizers, etc., as necessary. A vulcanizate can be easily obtained by a normal vulcanization method. The vulcanizing agent is arbitrarily selected from common vulcanizing systems such as sulfur-based, thiuram-based, and organic peroxides. By being vulcanized, the terpolymer rubber composition of the present invention has excellent sour gasoline resistance, alcohol-containing gasoline resistance, gasoline resistance, cold resistance, tensile strength, and elongation, and is useful for practical use. Since it provides a vulcanizate with a permanent compression set, it is preferably used as a material for various fuel rubber parts such as gaskets, gaskets, O-rings, and cab floats. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. [Examples 1 to 6, Comparative Examples 1 to 6] Examples 1 to 6 and Comparative Example 2 shown in the upper row of Table 2
NBF/PVC blend compositions of Comparative Examples 1, 3,
Terpolymer (NBF) of No. 4, NBR of Comparative Example No. 5,
Each polymer of the NBR/PVC blend composition of Comparative Example 6 was blended using a Banbury mixer according to the blending recipe shown in Table 1. The resulting mixture was press-cured at 150°C for 30 minutes to obtain a vulcanized product. Measure the physical properties of the vulcanizate according to the following method,
The results are shown in the lower part of Table 2. 1 Tensile test JIS K 6301-3 2 Hardness test JIS K 6301-5 JIS A type 3 Gasoline resistance test JIS K 6301-12 Test oil C (isooctane/toluene = 50/50
The volume change was measured after immersion in the mixture) at 40°C for 48 hours. 4 Alcohol-resistant gasoline test JIS K
6301-12 Measurement was carried out in the same manner as the gasoline resistance test, except that a mixture of test oil C/methyl alcohol = 80/20 (volume ratio) was used as the immersion liquid. 5 Sour gasoline resistance test After 6 cycles of immersion of the sample at 80°C for 24 hours in a test solution containing t-butyl hydroperoxide dissolved at a concentration of 50 mm/L in test oil C. , and dried under reduced pressure at 100°C for 15 hours. The cracking elongation and breaking elongation of this material were measured according to JIS K 6301-3. 6 Cold resistance (impact embrittlement test) JIS K 6301-14 7 Compression set JIS K 6301-10 Measured at 120°C x 70 hours. Table 1 Parts by weight of formulation ingredients Polymer 100 Zinc white 5 Stearic acid 1 MT carbon black ^*a) Variable ^*b) Plasticizer DOP ^*c) 20 Vulcanization accelerator TT ^*d) 1.8 〃 CZ ^*e) 2.0 Sulfur 0.5 *a) Medium thermal furnace
Black *b) The blending amount was adjusted so that the hardness of the vulcanizate was in the range of 70±5. *c) Dioctyl phthalate *d) Tetramethylthiuram disulfide *e) N-cyclohexyl-2-benzothiazole sulfenamide

【table】

[Table] As is clear from Table 2, the NBF/
PVC blend composition has excellent gasoline resistance,
It has alcohol-containing gasoline resistance and sour gasoline resistance, and has significantly improved tensile strength and cold resistance compared to ordinary NBR blended with PVC (Comparative Examples 5 and 6), making it practical. Combined with a high compression set, it is possible to provide an excellent fuel rubber material.

Claims (1)

[Scope of Claims] 1 Terpolymer 97 consisting of 15 to 60 mol% of α,β-unsaturated nitrile, 10 to 75 mol% of conjugated diene, and 2 to 55 mol% of fluoroalkyl (meth)acrylate
A terpolymer rubber composition comprising ~40 parts by weight and 3 to 60 parts by weight of a vinyl chloride resin. 2. The terpolymer rubber composition according to claim 1, wherein the α,β-unsaturated nitrile is acrylonitrile. 3. The terpolymer rubber composition according to claim 1, wherein the conjugated diene is butadiene-1,3. 4. The terpolymer rubber composition according to claim 1, wherein the fluoroalkyl group of the fluoroalkyl (meth)acrylate has 1 to 15 carbon atoms.