JPS58219243A - Rubber compound - Google Patents

Abstract

PURPOSE:A rubber compound that is made by adding a nonreinforcing inorganic filler and asphaltene to an elastomer mainly composed of halogenated butyl rubber, thus showing remarkably improved vulcanizing adhesion as well as tackiness, air-trapping, roll-releasability and other processing properties. CONSTITUTION:The compound comprises 100pts.wt. of an elastomer, which contains 50-100pts.wt. of halogenated butyl rubber in 100pts.wt. of the elastomer, 5-30pts.wt., preferably 10-20pts.wt. of nonreinforcing filler such as silicic acid, aluminum silicate, calcium sulfate and 5-30pts.wt., preferably 10-20pts.wt. of asphaltene such as straight asphaltene or blown asphaltene. During mixing above 130 deg.C, asphaltene bearing functional groups adheres to the surface of the filler through secondary bondings to form a high-dimensional structure between them. Thus, the surface of resultant compound is activated due to its higher molecular weight, wider molecular weight distribution, higher surface activity and higher dimensional structure of functional groups than only asphaltene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a remarkable improvement in vulcanization adhesion that provides a large adhesive strength after vulcanization between a halogenated butyl rubber compound and other diene-based rubber compound, as well as a one-step calendering process. It has achieved remarkable improvements in processability such as tackiness, reduced air entrainment, and roll release properties as an unvulcanized rubber compound, which are strongly required in the molding and molding process, and is particularly suitable for automobile tires. It is intended for formulations with

Conventionally, in a method for improving the vulcanization adhesion between a rubber compound containing halogenated butyl rubber as a main component and another diene-based rubber compound, the prior art is disclosed in Japanese Patent Application Laid-Open No. 57-1262.
Publication No. 7 discloses a technique for blending 8 to 15 parts by weight of blown asphalt and 1 to 6 parts by weight of dibenzothiazyl disulfite in a halogenated butyl rubber compound as a method for improving adhesive properties. In addition, JP-A-57-14686 discloses a method for improving adhesive properties in which 20 parts by weight of a rubber compound containing chlorinated butyl rubber and brominated butyl rubber is blended in a blend ratio of about 95:5 to about 50:50. Techniques for blending mineral rubbers have been disclosed.

The improvement in adhesion obtained by the above-mentioned conventional techniques was still insufficient. Furthermore, there were problems with workability.

In addition, for inner liners of pneumatic tires, in addition to adhesive strength, we also evaluate the adhesion of processed rubber materials, the degree of air entrainment into the rubber sheet to determine the difficulty of bubbles, and the calendering and molding process, such as roll release properties. It is necessary that the compound has excellent processability in
In this respect, it was insufficient.

Therefore, the inventors investigated the factors that can be obtained in both adhesion and processability properties in a naro rubber compound made from an elastomer containing halogenated butyl rubber as the main component, and determined the suitability of asphalt and inorganic filler. We found a synergistic effect.

8 First, the types of inorganic fillers include clay, mica, aluminum silicate such as bentonite, magnesium silicate such as talc and asbestos, heavy charcoal, light charcoal, etc. , calcium carbonate type like chalk, calcium sulfate type like gypsum, barium sulfate type like pallite, other aluminum oxide type, aluminum hydroxide type, calcium oxide type, magnesium oxide type, silicic acid type like silica, etc. Alternatively, the surface of the above-mentioned inorganic filler is treated with a 9-run coupling agent, etc. In other words, the bonding force with the rubber is weak, and even if a large amount is blended, the modulus of the vulcanized rubber will not be very high. A non-reinforcing filler has a synergistic effect in combination with asphalt, which has the effect of significantly improving both adhesion and processability.

Among these, aluminum silicate-based materials such as clay, mica, and bentonite are particularly effective. In addition, as for the blending amount to 100 parts by weight of elastomer, an effect tends to be observed from about 5 parts by weight, but the effect is remarkable in terms of both adhesion and processability properties as well as overall properties at about 10 to 20 parts by weight. . Less than 5 parts by weight has no effect; on the other hand, 30 parts by weight
If the amount exceeds 1 part by weight, the physical properties such as tensile strength of the vulcanized rubber will be greatly reduced, which is inappropriate.

Next, as for the type of asphalt, straight asphalt (ST
RAIGHT ASPHALT), blown asphalt (BLOWN ASPHALT) produced by blowing air into the residue at high temperature and oxidative polymerization, or asphalt produced as a derivative of these with some minor changes, but with inorganic filling. The synergistic effect of the combination with the agent is to significantly improve both adhesion and processability.

Further, as for the amount of asphalt added to 100 parts by weight of the elastomer, similar to the inorganic filler, an effect tends to be observed from about 5 parts by weight, but the effect is remarkable in terms of overall properties at about 10 to 20 parts by weight.

Therefore, if the amount is less than 5 parts by weight, no effect will be observed;
If it exceeds 0 parts by weight, physical properties such as tensile strength will deteriorate, which is inappropriate.

Regarding halogenated butyl rubber, conventionally, the weight of halogenated butyl rubber is 50 parts by weight or less in 100 parts by weight of the elastomer used, and diene rubber (natural comb, polybutadiene rubber, styrene-butadiene rubber, etc.) is used. With compounded rubber containing 50 parts by weight or more, there are no problems with vulcanization adhesion with compounded rubber whose main component is diene rubber, even with conventional technology. Processability as an unvulcanized rubber compound, such as releasability, is generally not considered a problem at present.

Therefore, in the present invention, the content of halogenated butyl rubber is 50 parts by weight to 1 part by weight in 100 parts by weight of the elastomer used.
00 parts by weight of compounded rubber containing halogenated butyl rubber as the main component and compounded rubber containing diene rubber as the main component, as well as uncured properties such as tackiness, air entrainment, and roll release properties. A rubber compound that prevents deterioration in processability as a sulfur rubber and has excellent adhesion and processability is obtained. In addition, the elastomer to be blended in an amount of less than 50 parts by weight other than the main component, halogenated butyl rubber, is one in which natural rubber or other various diene rubbers are used. The synergistic effect between the non-reinforcing inorganic filler and asphalt in this preferred rubber compound is that the molecular weight is higher than that of general process oils, the molecular weight distribution is wider than that of general resins, and it has functional groups. The asphalt is
About 130'C! It is thought that during the above mixing, adhesion occurs through secondary bonding on the surface of the inorganic filler, forming a higher-order structure of the inorganic filler and asphalt. Compared to asphalt alone, this higher-order structure has a macroscopically very high molecular weight and wide molecular weight distribution, and is a functional substance, so it can also affect the surface of the elementally stable halogenated butyl rubber compound. It is something that activates.

This effect improves adhesion and activates the surface through high-temperature oxidation in one calendering step, improving adhesion with diene rubber compounds and reducing air-entrained dust in the rubber sheet, i.e., preventing air entrainment. Furthermore, it is presumed that the asphalt adsorbed on the metal oxide surface reduces the metal bond with the roll surface, thereby improving roll release properties. Next, test results for various compounded rubbers will be shown.

The following Tables show various compounded rubber compositions, and Tables B show physical property values for the compounded compositions in Table A.

4*・The abbreviation GPF is GENERAL PURPO5E
FURNACE BLACK5*...Blonoasphal 110-206 manufactured by Showa Sekiyu Co., Ltd.*...Symbol DM is dibenzothiadyldisa, ide Table 1-B (physical property value table) 0 0 ■D 2.2 D ■ 5 7 2 0 The physical properties in Table 1-B above were measured and expressed using the following method.

5 Adhesive strength Adhesive strength is determined by pasting together a rubber sheet with a width of 25.4 mm (1 inch) and a thickness of 8 mm, mainly composed of halogenated butyl rubber, and a rubber sheet mainly composed of diene rubber. A reinforcing cloth topped with rubber was attached to the sheet side using a calender, and then heated at 150°C for 9
After vulcanizing for 0 minutes and leaving at room temperature for 24 hours, the peel strength was determined by JI.
It was measured according to the regulations of SK6801 (1975). Record the peeling condition at that time with @ID and 1. Shown in Abbreviation ID
(INTERMOLECULARDEBONI)IN
In G), the molecules of both rubber sheets were well diffused, and the rubber sheets were peeled off irregularly, that is, intermolecularly peeled within the rubber molecules.

The abbreviation 1p (INTERFACE PEELING) indicates that the adhesion was insufficient and the two rubber sheets were separated at the interface, resulting in interfacial peeling.

8 Adhesion.

Adhesive strength is based on halogenated butyl rubber with a width of 10
Wrap an unvulcanized rubber sheet of mm x 4 mm thickness around a ring, press it with a constant load onto the same unvulcanized rubber sheet,
Measured using a pickup method.

KID was peeled off within each comb sheet as in the case of the adhesive force.

Similarly to the above, the abbreviation (■) also indicates peeling between both rubber sheets.

50 - Roll release property Roll release property required for smooth roll work and calendar work is evaluated in 5 grades. Number 1 indicates good roll release property, and number 5 indicates excessive adhesion. This shows that the roll separation property is the worst.

5 Degree of air entrainment The degree of air entrainment in which air is trapped within the rubber sheet and between sheets during calendering work, that is, the degree of air entrainment in the rubber sheet, is the degree of air entrainment in the rubber sheet during the calendering process. The evaluation is based on the number and size of the rubber, and the number 1 indicates that the rubber is the least likely to contain air, indicating that the number of air bubbles is small and good. This shows that the sheet condition is the worst.

h Hardness - Other @Note Rubber hardness is determined by the constant load of 1ISK6801 (1975) (
Measured by Olsen hardness test method.

Other physical properties were measured according to JIS K6801 (1975).

(Notes) 1*-6* Same as footnotes in Table 1-A.

The same applies to Tables 8 to 6 below.

Table 2-B (Physical property value table) The physical property values in Table 2-B above were measured using the same measurement method as in Table 1-B.

The same applies to Tables 3 to 6 below.

Table 8-B (physical property value table) Table 4-B (physical property value table) Table 6-B (Physical Property Price List) Table 6-A (Rubber composition table) Defined as a non-complementary inorganic filler.

Table 6-B (Physical property value table) As shown in the test results for each compounded rubber composition above, in the compounded rubber compositions in Table 1-A1 and Table 2-, compounding No. 8 containing 50 parts by weight or more of halogenated butyl rubber, had poor adhesion and peeling properties, but Blend No. 4, which contained 15 parts by weight each of clay and asphalt, had significantly improved adhesion and excellent results in adhesive strength, roll releasability, and air-entrained dust. show.

In addition, as is clear from formulations Nos. 6, 7, 8, 9, and 10, those using clay or asphalt alone or without using adhesive strength, roll release properties,
Air-entrained dust is also a problem, but those using clay and asphalt have shown excellent results.

Further, similar results were obtained when using 100 parts by weight of halogenated butyl rubber.

In addition, as shown in Table 3-A1 and Table 4-A, the amount of clay and asphalt used tends to be effective when each is used in amounts of 5 parts by weight or more, and particularly when the amounts of each are 10 parts by weight or more, a remarkable effect is shown. Even with 30 parts by weight of each, the effects on adhesion and processability are remarkable, but the breaking strength tends to decrease, so the usage range is 5 to 30 parts by weight, and the most preferable range is about 10 to 20 parts by weight. Practically preferred.

Aluminum silicate-based materials are preferable in terms of overall properties.

Agent Patent Attorney Yasuichi Oshima

Claims (1)

[Claims] (1) In a compound mainly composed of halogenated butyl rubber containing 50 to 100 parts by weight of halogenated butyl rubber in 100 parts by weight of elastomer, 5 to 30 parts by weight of a non-reinforcing inorganic filler per 100 parts by weight of elastomer. A rubber compound comprising 5 to 30 parts by weight of asphalt.