JPS61143455A - Rubber material for gas-filling use - Google Patents

Abstract

PURPOSE:To obtain the titled material capable of effectively preventing gas permeation without having any adverse effect on various rubber characteristics, suitable for tennis balls, etc., by incorporating feedstock rubber with flaky or plate-like filler. CONSTITUTION:The objective material can be obtained by incorporating (A) 100pts by wt of feedstock rubber (e.g., natural rubber, synthetic rubber such as butadiene rubber or isoprene rubber) with (B) 1-150 (pref. 3-80) pts by wt of flaky or plate-like filler (e.g., sericite, kaolin chlorite, aluminum silicate) and (C) as optional ingredients, sulfur, curing accelerator, deterioration inhibitor, dye, etc. Curing of this material under high pressure during molding process will orient the filler (B), the material thus acting as a shielding material preventing gas permeation.

Description

[Detailed Description of the Invention] [. INDUSTRIAL APPLICATION FIELD The present invention relates to a rubber material for gas filling, and more particularly to a rubber material for gas filling that is optimal as a rubber material for a hollow pole, in which permeation of the filled gas is significantly reduced.

[Prior Art] Hollow poles for sports such as tennis balls are generally made of a rubber material such as natural rubber or synthetic rubber and filled with air or various gases at a pressure higher than that of the atmosphere.

An example of a method of manufacturing a tennis ball that has been commonly used will be described below.

First, various additives are added to raw rubber and kneaded to produce pellets of compounded rubber.Next, the pellets are placed in a hemispherical mold and heated to form a bowl-like hemispherical shape, with excess rubber protruding from the hemisphere. , remove the molded layer, etc., polish the surfaces to be joined, and apply rubber glue. A certain amount of gas generating agent is placed inside one of the two hemispheres treated in this manner, and the two hemispheres are bonded together to form a spherical pole. This material is placed in the spherical mold again and heated to press the joint surfaces together. At this time, the gas generating agent reacts and foams due to heating, and a hollow sphere having a constant internal pressure is obtained. After polishing the outer surface of the obtained hollow sphere and applying rubber glue, Melton cloth is pasted on it, and it is heated again in the mold to fully adhere the Melton cloth. The poles coated with melton in this manner are subjected to raising of the melton to improve their appearance and feel, and after standard inspection, they are made into products. Note that the above bonding may be performed in an atmosphere at a pressure higher than atmospheric pressure without using a gas generating agent, thereby causing high pressure gas to remain within the bonded spheres.

[Problems to be Solved by the Invention] However, since the conventional pole manufactured in this way is filled with gas at a pressure higher than the atmosphere, the inside of the pole may deteriorate as the pole is used or over time. The gas leaks out through the rubber membrane, and the pressure inside the pole gradually decreases. For this reason, the elasticity and repulsion performance of the pole deteriorates, and the product standard (for example, in the case of tennis balls, 254
Bounce when falling from 135-147 cm
It is said that ), and changes in the feel of the ball result in changes in play. Furthermore, the rubber membrane is more severely worn out due to gas permeation.

Conventionally, in order to prevent such gas leakage, a method has been proposed in which a powdery filler is added to the raw rubber and molded, but a sufficient gas leakage prevention effect has not yet been achieved.

C. Means for Solving Problems] The present invention has been made to solve the above problems, and provides that the scale-like or tabular filler is added to 100 parts by weight of rubber,
The gist of the present invention is a rubber material for gas filling, characterized in that the rubber material is contained in a range of 1 to 150 parts by weight.

That is, the present inventors have made intensive studies to provide an excellent rubber material for gas filling without gas leakage, and as a result, the present inventors have found a material that can be obtained by kneading a scale-like or flat-like filler into raw rubber and molding it. The present invention was achieved based on the discovery that the rubber membrane obstructs the passage of gas and effectively prevents gas leakage.

The present invention will be explained in detail below.

The rubber material for gas filling of the present invention contains 1 to 150 parts by weight of a flaky or flat filler per 100 parts by weight of raw rubber.

There is no particular restriction on the type of raw rubber, and it may be either natural rubber or synthetic rubber. Examples of synthetic rubber include butadiene rubber (BR), imprene rubber (IR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber ( NBR), chloroprene rubber (C
Diene rubber such as R); butyl rubber (IIR), halogenated butyl rubber, acrylic rubber (ACM, ANM),
Olefin rubbers such as ethylene propylene rubber (EPDM, EPR), chlorosulfonated polyethylene, ethylene vinyl acetate copolymer (EVA), chlorinated polyethylene, fluororubber; other silicone rubbers, silicone 1-2-propylene rubber, urethane rubber Polymers such as

In the present invention, such a raw rubber is made to contain a scaly or tabular filler, but if the content of the scaly or tabular filler is too small, the gas leakage prevention effect will be insufficient. If the amount is too large, it will have a negative effect on the properties of the rubber material such as elasticity. Therefore, the content of the scale-like or tabular filler is 1 to 150 parts by weight, preferably 3 to 80 parts by weight, and more preferably 5 to 30 parts by weight, based on 100 parts by weight of the raw rubber.

There are no particular restrictions on the scale-like or tabular filler.
Commonly used thin plate-shaped fillers are used, including sericite, kaolin, chloride, aluminum silicate,
clay, talc, mica.

Scale-like or tabular fillers such as molybdenum disulfide and graphite are suitable. Specifically, the following scaly or tabular fillers may be mentioned.

■Sericite type Super light (manufactured by Kobe Clay Co., Ltd.) Sericite-based hexagonal flat grains.

Specific gravity: 2.58 Composition (%): 5i02; 57.31 A sentence 203; 26.46 Fe203; 1.78 20, 4.52 Na20; 0.59 CaO; 0.49 Mg0.1.96 pH near, 60 Ignition loss: 6.62% HY-100 (manufactured by Takara Sangyo) Fine scaly powder of sericite.

Specific gravity: 2.5-2.83 Composition (%): SiO2; 45-52 AfL203; 30-35 Fe203; 3 or less K20; 8-11 CaO; 1 or less pH: 5-7 Ignition loss: 5-7 % (Others, HY-300, HY-400, HY-5, Y
K, HY-200 (all manufactured by Takara Sangyo Co., Ltd.), Sanshin Sericite FS, -5C1 to 8-5, etc.) U) Kaolin Neosuper A (manufactured by Kobe Clay Co., Ltd.) SB clay
B (manufactured by Kobe Clay Co., Ltd.) Kaolin-based hexagonal flat granules.

Composition (%): SiO2; 57.73 A also 203; 2B, 91 Fe 20a; 1.14 CaO; 0.30 Mlio, 0.10 pH: 5, 5 Ignition loss: 1O, 60% ■Chloride type Swany-Z (manufactured by Showa Mining Co., Ltd.) Ultrafine powder and thin plate-shaped crystals of chloride.

Specific gravity: 2.6g Composition C%): S i 02; 37-40AfL
203; 17-18 Fe203; O, 1-0.5 Mg0; 30-32 CaO; 0.1-0.5 Na20; 0. INo, 2 pH near, 4 Ignition loss: lON110% (Others such as Swa 21 30 (manufactured by Showa Mining Co., Ltd.)) ■Aluminum silicate based A S P 100 (Engelhar
d Minerals & Chew, Inc.) Thin plate-shaped hydrated aluminum silicate.

Composition (%): SiO2; 45 AJ1203; 38.8 Fe20:1; 0.3 Ti02; 1, 5 Cab; 0. I Na 20; 0-1 Moisture; 1 or less pH: 3.8-4.6 Loss on ignition: 13.8% (Others: ASP170, ASP200, ASP400
P, ASP600 (L deviation is also Engelhard Mi
nerals & Chew, Inc.) ■Clay-based I c e c a K (Burgess Pi
g+5ent (manufactured by US company) A thin, flat plate-shaped anhydrous clay.

Specific gravity: 2.63 Composition (%): 5i02; 51.0-52.4Al 20
3; 42. 1 to 44.3 Fe20a; Trace TiO2; 1.56 to 2.50 Water; 5 or less pH: 5 to 6 Loss on ignition 20 to 1.0% (Others: Iceberg, Thernoglac
e, H, No, to, B-80.

Ti5yn (both Burgess Pigment
0 talc-based tanoshiri (talc) - talc, soapstone, dalcum, → wrench chalk,
It is called steatite and its ingredient is hydrated magnesium silicate.
Theoretically, Mg031.7%, 5iO263.5%, H
204.8 ice.゛Asada Seifun 2 Domestic Sulfide Industry, Takehara Chemical Industry, Ueya Orient Industry, Nitto Flour Chemicals, Nippon Talc, Maruya Calcium, I
International Ta1e and Nippon Mistron's products are famous.

■Mica Powder composition (%)
): SiO2; 44-48 AJ1203; 35-40 CaO; 2 or less Fe2O3; 3 or less K20; 8-12 Loss on ignition: 5-7% ■Molybdenum disulfide
fide) trade name Molycoat is generally used, and products from Fuji Kobunshi and Dou learning are used.

■Graphite-based Graphite from Hokkaido, Ceylon, and Madagascar is common.

The rubber material of the present invention may contain normally added sulfur, vulcanization accelerator, anti-aging agent, dye, etc. in addition to the raw rubber and the above-mentioned scale-like or flat filler. Of course.

In order to manufacture products such as tennis balls using the rubber material of the present invention, it is possible to use normally employed manufacturing methods. It comes to act as a shielding material that obstructs the passage of gas.

Such a rubber material of the present invention is extremely useful as a material for rubber products filled with pressurized gas, such as poles for tennis balls, tire tubes, built-in rubber of tubeless tires, and the like.

[Function] Since the rubber material of the present invention contains a scale-like or tabular filler, this filler significantly suppresses the passage of gas and prevents gas leakage. Moreover, the content of the scale-like or tabular filler is 1 to 150 parts by weight per 100 parts by weight of raw rubber.
Since it is a part by weight, it can effectively prevent the passage of gas without affecting the properties of the rubber.

Therefore, when a tennis ball is manufactured using the rubber material of the present invention, leakage of gas filled inside the ball through the rubber membrane due to use of the pole, passage of time, etc. is greatly reduced, and the inside of the pole is It becomes possible to maintain this pressure for a long time. Therefore, the elasticity and repulsion performance of the pole will not deteriorate, and the play will not be affected.In addition, since gas passage through the rubber membrane is prevented, deterioration of the rubber membrane is prevented, and the filling The agent strengthens the rubber membrane, so the pole can be used until the outer covering layer wears out.
The life of the pole is also extended.

[Examples] The present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Examples 1 to 8, Comparative Example 1 Tennis balls were manufactured using rubber materials having the compositions shown in Table 1 according to conventional methods. As the scale-like or tabular filler, Super Lakanto (manufactured by Kobe Clay Co., Ltd.) was used.

First, raw rubber pellets are placed in a hemispherical mold, and 15 (
1 for 13 minutes to produce a half cup. After treating the joint surfaces of the half cups, rubber glue was applied, and the two half cups were brought together and joined in a pressurized atmosphere of 1.8 atmospheres using a one-spherical mold to form a sphere. This was further coated with Melton to form a tennis ball.

When the manufactured tennis ball was dropped from a height of 254 cm, the bounce height (rebound) was measured, and the change over time in the decrease value was investigated.

The results are shown in Table 1.

Examples 9 to 17 The scaly or plate-like fillers shown in Table 2 were
A tennis ball was produced in the same manner as in Example 4, except that 10 parts by weight was used per 100 parts by weight of raw rubber.
We investigated the change in rebound decline over time.

From Tables 1 and 2, it is clearly seen that according to the present invention, the rebound characteristics of tennis balls can be made good over a long period of time.

In addition, from Table 1, it is recognized that the rubber material containing the scale-like or tabular filler of the present invention shows little decrease in rebound even after a long period of time, and gas leakage is significantly reduced. It is observed that as the amount of scale-like or tabular filler added increases, the decrease in rebound properties becomes smaller.

Furthermore, from Table 2, although there are some variations depending on the brand of filler, it is recognized that all of them can maintain rebound physical properties for a long period of time compared to the conventional product (comparative example).

[Effects] As detailed above, the rubber material for gas filling of the present invention contains 1 to 150 parts by weight of a scale-like or flat filler based on 100 parts by weight of raw rubber, and the rubber material Permeation of dregs can be suppressed without adversely affecting properties such as elasticity. Furthermore, deterioration of the rubber is also prevented.

Therefore, according to the rubber material for gas filling of the present invention, it is possible to prevent the leakage of the filled gas in a wide range of fields such as hollow poles such as tennis balls, tire tubes, etc., and to manufacture excellent rubber products with a long life. It is extremely useful industrially.

Claims (1)

[Claims] (1) A rubber material for gas filling, characterized in that a scale-like or tabular filler is contained in a range of 1 to 150 parts by weight based on 100 parts by weight of rubber.