JPH0141655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber composition, and more particularly to a rubber composition having good processability and excellent rubber physical properties, which is obtained by blending a specific liquid rubber with a solid rubber. Recently, solid rubber has come to be required to have extremely high mechanical properties. For this,
Large amounts of various additives are blended, and although the mechanical properties are improved, the processability is significantly reduced. Therefore, it is strongly desired to improve workability while maintaining high mechanical properties. In view of this point, the present inventors have conducted detailed studies, particularly regarding the technique of adding liquid rubber to solid rubber. As a result, a special liquid rubber that has a hydroxyl group at the end of the molecule and an epoxy group inside the molecule instead of at the end of the molecule improves the processability of solid rubber, while not degrading the excellent physical properties of solid rubber. Based on this knowledge, we have completed the present invention. That is, the present invention provides a rubber composition in which a solid rubber is blended with a liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule. As the solid rubber used in the present invention, styrene-
Examples include butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), natural rubber (NR), chloroprene rubber (C), and isobutylene-isoprene rubber (IIR). Next, let's talk about liquid rubber that has a hydroxyl group at the end of the molecule and an epoxy group inside the molecule.
Liquid rubber refers to a polymer that is fluid at room temperature, forms a three-dimensional network structure through appropriate chemical treatment, such as curing treatment, and exhibits the same physical properties as ordinary vulcanized rubber. Examples of such liquid rubbers include rubbers with an average molecular weight that have a hydroxyl group at the end of the molecule.
500-8000 polybutadiene, polyisoprene,
Polystyrene, polychloroprene, polyethylene, butadiene/isoprene copolymer, acrylonitrile/butadiene copolymer, styrene/butadiene copolymer, so-called telechelic liquid rubber, liquid urethane rubber, liquid thiokol, pyrolytic rubber, ozone These include decomposed rubber and liquid silicon rubber. In the present invention, the above liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule is used. As such, liquid polybutadiene having an epoxy group inside the molecule is particularly preferable, and representative examples thereof include:
Examples include those represented by the following structural formulas. The blending ratio of each component in the rubber composition of the present invention is not particularly limited and may be determined as appropriate depending on the type of component used, the use of the composition, etc., but in general, per 100 parts by weight of solid rubber, The amount should be 1 to 100 parts by weight, preferably 20 to 80 parts by weight of liquid rubber having hydroxyl groups in the molecule and epoxy groups in the molecule. Incidentally, auxiliary components can be appropriately added to the rubber composition of the present invention as necessary, such as vulcanizing agents such as sulfur, zinc oxide, and magnesium oxide, calcium hydroxide, guanidines, and aldehyde amines. , vulcanization accelerators such as thiurams, carbamates, and thiazoles, dispersants such as stearic acid and naphthenic acid, process oils, softeners such as pine tar, curing catalysts such as hexamethylenetetramine, and reinforcements such as carbon black. Further, coloring agents, anti-aging agents, etc. can be mentioned. Furthermore, the following can also be used as an additive for the above-mentioned liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule. That is, blowing agents such as trichloromonofluoromethane, curing catalysts such as stannous chloride and triethylamine, reinforcing agents such as polyols, polyamines, and polycarboxylic acids, curing agents such as diisocyanate compounds, inorganic materials such as pigments and fillers, Anti-aging agents such as ultraviolet absorbers, antioxidants and ozone deterioration inhibitors, workability improving agents such as extender oil, etc. can be added as appropriate. In addition, in manufacturing the rubber composition of this invention, there is no restriction|limiting in particular in the method, and various methods can be employ|adopted. For example, first, a liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule is added to a solid rubber, a curing catalyst is added if necessary, and then this mixture is used together with optional auxiliary components. Knead for 10 to 60 minutes at a temperature of 55±5°C using two rolls or the like. Subsequently, the obtained kneaded product is heated and pressurized at a temperature of 120 to 180°C, preferably 135 to 160°C, and a pressure of 35 kg/cm ² or more, preferably 60 to 120 kg/cm ² . The desired rubber composition is thus obtained. The rubber composition of the present invention has excellent moldability and retains the elasticity inherent to solid rubber without losing it. Therefore, the rubber composition of the present invention can be effectively used as tires or various cushioning materials. Next, examples of the present invention will be shown. Examples 1 and 2 and Comparative Example 1 100 g of SBR as a solid rubber, a liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule (indicated simply as "liquid rubber" in Table 1) and others A predetermined amount of each of the auxiliary ingredients is mixed and kneaded using two rolls at a temperature of 55±5℃ to obtain a kneaded product, which is then kneaded at 145℃ and 120kg/
A rubber molded product was obtained by pressure molding for 16 minutes using a press molding machine under conditions of cm ² . The properties of this rubber molded product are shown in Table 1 along with the experimental conditions. Example 3 and Comparative Example 2 Except for Example 1, except that NR was used instead of SBR as the solid rubber, the molding temperature was 140°C instead of 145°C, and the molding time was 32 minutes instead of 16 minutes. The same operation as in Example 1 was performed to obtain a rubber molded product. The properties of this rubber molded product are shown in Table 1 along with the experimental conditions. Reference Example Same as Example 1 except that a glycidyl group-containing diene-based low molecular weight copolymer was used instead of the liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule. I went to The results are shown in Table 1. As is clear from the table, the tear strength and elastic modulus of the rubber moldings were significantly reduced. 【table】

Claims (1)

[Scope of Claims] 1. A rubber composition obtained by blending a solid rubber with a liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule. 2. The rubber composition according to claim 1, which contains 1 to 100 parts by weight of a liquid rubber having a hydroxyl group at the end of the molecule and an epoxy group inside the molecule per 100 parts by weight of the solid rubber. 3. Claim 1, wherein the solid rubber is styrene-butadiene rubber, acrylonitrile-butadiene rubber, natural rubber, or chloroprene rubber.
The rubber composition described in . 4. The rubber composition according to claim 1, wherein the liquid rubber is liquid polybutadiene.