JPS60208353A - Rubber composition for low-resilience elastomer - Google Patents

Abstract

PURPOSE:To provide the titled composition capable of giving elastomer of high rigidity, low specific gravity and low resilience along with such characteristics so as to be excellent in touch and suitable for golf grip etc., comprising polynorbornene, oil, specific unsaturated carboxylic acid, and magnesium ion. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100pts.wt. of polynorbornene with (B) 60-220pts.wt. of an oil compatible therewith (e.g. aromatic, or naphthene-based one) and (C) 10-40pts.wt. of 3-8C alpha,beta- monoethylenic unsaturated carboxylic acid (e.g. acrylic acid, methacrylic acid) followed by graft polymerization on heating in the presence of such an amount of magnesium ion as to be equivalent or lower based on the existing carboxylic acid group.

Description

[Detailed description of the invention] The present invention relates to a rubber silk composition capable of providing the following properties.

Conventionally, the low-repulsion elasticity rubbers used in golf clazogrinos, tennis rackets, etc. have been made by blending various fillers with isobutylene isoprene rubber (hereinafter referred to as F.IIR) and vulcanizing it with sulfur. Proposals include polynorbornene (trade name: Norsolenox, sold by Zeon Co., Ltd.) mixed with various fillers along with I+B and vulcanized with sulfur. However, the hardness of these compounds is generally low, and a large amount of filler must be added to achieve a JISA hardness of 45-1.

However, when a large amount of filler is added, Ll in IIH, as is clear from the comparison between curve C and curve A shown in Figure 1, the rebound is low, and at the same time, the specific gravity is lower than that shown in Table 1 below. as shown in the figure. In addition, in the case of polynorbornene, although the hardness is high as shown in Table 2, the specific gravity is also high, and as shown in Table 3, the tear strength is weak and The bullet 1+1 ratio was also high and there were practical 11 problems.

The present inventors have conducted various studies in view of the above circumstances, and have found that by adding oils that are compatible with polynorbornene to polynorbornene, 3 to 8 carbon atoms are graft-polymerized to the polynorbornene. 10 to 40 parts (parts by weight, the same shall apply hereinafter) of linorbonene, an α,β-monoethylenically non-saturated saturated carboxylic acid having It has been found that when present, a rubber composition can be obtained which can be graft-polymerized by heating under pressure to provide a low-curing elastic body having high hardness, low specific gravity, and good texture and feel. This led to the completion of the present invention.

Zunawara, as described in Section 2, when oil is added to polynorbornene, α, β-monoethylenic saturated carboxylic acid is combined, and magnesium ions are present as desired, and heated. In addition, an unsaturated carboxylic acid or its magnesium salt is graft-polymerized onto the main chain of polynorbornene, increasing its hardness. This allows the amount of reinforcing filler to be reduced, and it is possible to increase the specific gravity with the same hardness and strength. Smaller formulations can be obtained.

In addition, since the carboxylic acid is sufficiently neutralized with magneum ions and then polymerized according to graph 1, a compound with good release from the mold can be obtained. Moreover, due to the effect of the added oils, the degree of energy absorption is high, particularly at -10°C (: ~ → 30°C), and low repulsion is exhibited well. Also, the effect of the added oils allows the product to be puffed. This makes it possible to obtain a low-repulsion elastic body that gives a good texture to the product and feels moist on the hand when directly touched.

In the present invention, the oils added to polynorbornene include aromatic oils, naphthenic oils, paraffinic ivl+,
A mixed oil thereof or a mixed oil of those ib and OJ plasticizer is used. If these oils Yn+J are too small, the low repulsion elasticity will not be 10, and if too large, the strength will be low.
It is preferable to add about 220 parts.

These oils may be added at the time of blending, or may be added to the dry polynorbornene, or may be added during the production of polynorbornene.

Examples of α,β monoethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and the like. As mentioned above, these unsaturated carboxylic acids are used in an amount of 1 part per 100 parts of polynorbornene.
0 to 40 parts are blended. This is because if the amount of the α,β-unsaturated carboxylic acid blended is less than the above range, it will be difficult to obtain a product with high hardness, and if it is more than the above range, the hardness will be high but the specific gravity will also be high.

Magnesium ions are present in an amount equivalent or more to the carboxylic acid groups present, but if there are too many magnesium ions, the specific gravity will become high, so the amount should be 4 times or less relative to the carboxylic acid groups. is preferable. This magnesium ion is usually blended in the form of magnesium oxide when preparing a rubber composition. Generally, zinc ions (usually blended in the form of zinc oxide) are often used for graft polymerization of unsaturated carboxylic acids onto the polymer main chain, but zinc ions do not easily release from the mold and require a large amount of money for separate molding agents. It takes. Calcium also has a similar purpose.
Calcium oxide is sometimes used as a binder, but it is not preferred because calcium oxide tends to absorb moisture from the air and turn into calcium hydroxide, which significantly reduces the hardness of the formulation.

The rubber composition IJ of the present invention, as described above, contains polynorbornene, oil, α,β-monoethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms, and magnesium ions as essential components, - A reinforcing agent, a Ja filler, a peroxide for initiating the progress of graft polymerization, and the like are suitably blended into I in accordance with a conventional rubber compounding recipe. In addition, if desired, ethylene propylene diene rubber (hereinafter referred to as EP)
DM), styrene-butadiene rubber, high water lilylene rubber, and other polymers and anti-aging agents may be blended.

However, when blending polymers, make sure that all polymers are 11140ffllf so as not to impair the properties of polynorbornene.
It is necessary to keep it below t%.

The rubber elastic body obtained by heating the rubber composition described in item 1 under pressure has high hardness, low specific gravity, and low repulsion, and has a rough texture and feel. And the hardness is JIS
A of 45 or more and specific gravity of 1.10 or less.

This rubber composition is suitably used for manufacturing the aforementioned golf club grips, tennis racket grips, insoles for golf shoes and tennis soyuz, rubber rolls, grips for chainsaws and rock drills, and the like.

Next, the present invention will be explained in more detail by giving Examples, Control Examples, and Comparative Examples.

Example 1 A reinforcing filler was added to 100 parts of +1R in the amounts shown in Table 1, and sulfur and a vulcanization accelerator were added to vulcanize, and the hardness and specific gravity were measured.

The results are shown in Table 1. Furthermore, FIG. 1 shows the change in the rebound modulus of the vulcanized rubber as the temperature changes. In Figure 1, curve A shows the case of combination A in Table 1, and curve B
Curve C shows the case of B combination in Table 1, and curve C shows the case of C combination in Table 1.

Table 1 As shown in Table 1, when the ratio of reinforcing filler to IIR is increased to increase hardness, the specific gravity increases, and as shown in Figure 1, the low 18 elastic properties are impaired. become.

Comparative Example 2 Carbon, calcium carbonate and naphthenic oil were blended in the proportions shown in Table 2 with respect to 100 parts of polynorbornene, and sulfur and a vulcanization accelerator were added and vulcanized.

The hardness and specific gravity of the obtained vulcanized rubber are shown in Table 2.

Table 2 As shown in Table 2, in order to increase the hardness of sulfur-vulcanized polynorbornene, it is necessary to increase the amount of reinforcing fillers such as carbon and calcium carbonate.
As a result, the specific gravity becomes high.

Examples 1 to 4 and Comparative Examples 1 to 2 Rubber compositions having the formulations shown in Table 3 were prepared and vulcanized under predetermined conditions.

The hardness, specific gravity, tensile strength and tear strength of the obtained vulcanized rubber were measured. The results are shown in Table 3. Further, FIG. 2 shows changes in the rebound modulus of the vulcanized rubbers taken from Example 1 and Comparative Example 1 with changes in temperature.

For compounded materials that are indicated by trade names or abbreviations, the manufacturer's name, official name, etc. are shown after Table 3.

Vulcanization conditions were 170°C x 25 minutes for Examples 1 to 4, and Comparative Example 1.
The temperature was 180°C for 20 minutes, and the temperature for Comparative Example 2 was 160°C for 10 minutes. In addition, the impact elasticity modulus of each vulcanized rubber at 20°C was
Shown in the table. The rebound modulus was determined by dropping a vulcanized composition into a shape with a diameter of 16 mm from a height of 180 cm.
This was determined by measuring the repulsion height at that time. The reason why the above-mentioned method was used to measure the rebound modulus is that the method specified by JIS involves changing the temperature to increase the rebound modulus.

Nosolenox; Polynorbornene, Nippon Zeon Nisprene 505: Nisprene 60 manufactured by Sumitomo Chemical Co., Ltd.
0; EP93 manufactured by Sumitomo Chemical Co., Ltd.: r: + Buty1365 manufactured by Honsei Rubber Co., Ltd.: Hysol SAS-111 manufactured by Exxon Co., Ltd.: Nippon Petrochemical Co., Ltd., aromatic DO3: di-(2-ethylhexyl) sezanthene 2
55ZJ: Naphthenic process oil, Sasonisoku R100: Naphthenic process oil, Kyonipsil VN3: Made by Nippon Silikani Co., Ltd., Reinforced Whiten SB: Made by Shiraishi Calcium Co., Ltd., Filled Kyowa Magoo 150: Kyowa Chemical Industry Co., Ltd. Manufactured by: Omukai Shinko Kagaku Kogyo Co., Ltd., Canada TT; Tetramethylthiuram disulfide DM: Dibenzothiazyl disulfide M; 2-Mercaptobenzothiazine TBT-N:
Te1-butylthiuramdisulf'FTT-E:
Tellurium Diethyldithiocar 2 Co., Ltd. Group-based softener Bakate, plasticizer made by Noil Co., Ltd., softener made by Noil Co., Ltd., softener agent, sulfur accelerator Phytodruid Bamate No. 3A! However, the vulcanized rubbers of Examples 1 to 4 of the present invention have a high parabolic degree, a low specific gravity, and a low stage 1a elastic modulus.

Furthermore, as shown in FIG. 2, 3L is the vulcanization obtained from the rubber composition of the present invention: (lh is a low stage 1a bullet ('t is a vulcanization) preferably in the range of 10 to 130°C. The lowest point of the 1a bullet (1) rate is about 8°C, but this point can be changed by changing the polynorbornene and /llt types.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the change in the rebound modulus of IIH as the temperature changes, and FIG. There is a diagram e showing a decrease in the anti-1 elastic modulus. Patent applicant: Sumitomo Rubber Co., Ltd. 3 - Figure 1 Figure 2 Temperature (°C)

Claims (2)

[Claims] (1) polynorbornene, an oil that is compatible with the polynorbornene, and an α having 3 to 1 lflllll carbon atoms that is graft-polymerized to the polynorbornene.
, is characterized by containing 10 to 40 parts by weight of β monoethylenically unsaturated carboxylic acid based on the weight part of polynorbornene, and at least 2 equivalents of magnesium ions to the carboxylic acid groups present. A rubber composition for a low-reflection 18 elastic body. (2) The rubber composition for a low impact resilience body according to claim 1, wherein the oil is contained in an amount of 60 to 220 parts by weight per 10 fHt parts of polynorbornene.