JPS63130482A - Rubber crawler - Google Patents

Abstract

PURPOSE:To improve the abrasion resistance of a rubber crawler by blending a vulcanizable rubber with the fine short fiber of polyamide and a special reinforced rubber composition. CONSTITUTION:A reinforced rubber composition used in a crawler is formed with a 5-100 part by weight of fiber formable polyamide per 100 part by weight of vulcanizable rubber and a 0.1-5.5 part by weight of silane coupling agent per 100 part by weight of the polyamide and, as necessary, a 0.5-20 part by weight of adhesion giving agent par 100 part by weight of the vulcanizable rubber, being mixed and kneaded together at a temp. above the melting point of the polyamide. The obtained mixed and kneaded object is extruded and drawn at a temp. above the melting point of the polyamide, thereby, producing a reinforced rubber composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber crawler that has improved cut resistance and moldability, and is a lightweight product6 [If, Field of Industrial Application] Construction vehicles, agricultural use Particularly required performance for rubber crawlers such as tractors, JTs, and snowmobiles that mainly run on uneven surfaces is resistance to chips and scratches of the elastic crawler rubber material caused by contact with protrusions on the ground, and wear resistance. It is gender.

In the rubber crawler of the present invention, the rubber material for elastic footwear has good cut resistance, high tear strength and abrasion resistance,
Furthermore, the moldability is superior to that of conventional products.

[Prior Art] Various attempts have been made to improve the cut resistance and abrasion resistance of rubber materials for rubber crawlers, but improvements in cut resistance and abrasion resistance (evaluated by pico abrasion) have not been sufficient. In some cases, the Mooney viscosity of the rubber composition increases, the molding method becomes complicated, and the moldability of the rubber material deteriorates, resulting in an unsatisfactory result.

In other words, even if a rubber composition containing a large amount of carbon black is used to improve the cut resistance and abrasion resistance of a rubber material, the cut resistance and abrasion resistance are improved, but not sufficiently. On the contrary, there is a drawback that the Mooney viscosity of the composition increases and the weight of the product increases.On the other hand, when a rubber composition with a reduced amount of carbon black is used, #cutting performance and abrasion resistance deteriorate. be.

In addition, nylon cut fiber is 5 to 3
0 The method of adding PHR improves the durability to some extent compared to the one without adding fiber, but perhaps because cut fiber is used that does not bond with rubber at all, the cut fiber mixture is perpendicular to the ground plane. It needs to be molded, and its moldability is extremely poor.

[Problems to be Solved by the Invention] The present invention solves the drawbacks of the prior art, such as poor moldability, low cut resistance and low abrasion resistance, by blending a special reinforced rubber composition, To provide a rubber crawler with excellent moldability and good durability.

[Means for Solving the Problems] The present invention is characterized in that fine short fibers of polyamide capable of forming fibers are embedded in a vulcanizable rubber, and that the polyamide and the rubber are bonded together using a silane coupling agent. A reinforced rubber composition (A), a diene rubber (B), and a carbon black (C) are combined together via the following (
The problems of rubber crawlers are solved by using a rubber composition that satisfies conditions I) to (IV).

(I) The amount of the polyamide is 1 to 20 parts by weight per 100 parts of the total rubber component, and (II) the natural rubber and/or in the components (A) and (B).
Or the ratio of the total polyisoprene to the total rubber components is 6
(m) The amount of carbon black is 30 to 60 parts by weight based on the total 100 parts by weight of the rubber components, and (IV) The hardness of the vulcanizate was measured by JIS K6301A type spring type hardness test. Hardness is 55-75°.

In this invention, the vulcanizable rubber is a continuous phase, in which fine short fibers of polyamide capable of forming m-fibers are dispersed, and the polyamide and the vulcanizable rubber are bonded at the interface of the short fibers. It is necessary to formulate a reinforced rubber composition in which the
Despite incorporating polyamide fibers,
A rubber composition with excellent moldability can be produced, and by using this composition as a rubber material for elastic footwear, a rubber crawler with excellent cut resistance can be produced.

Hereinafter, the rubber crawler of the present invention will be explained in detail.

Vulcanizable rubbers used in the reinforced rubber composition constituting the rubber crawler of the present invention include natural rubber, polyisoprene, imprene-isobutylene copolymer, and 11! Mention may be made of hydrogenated butyl rubber, brominated butyl rubber, and mixtures thereof. Among these rubbers, natural rubber is preferred. When using synthetic rubber as the rubber, it is preferable to use a rubber containing a tackifier.The tackifier has excellent compatibility with rubber and has a tackifying effect on synthetic rubber. Any tackifier that has a non-reactive to very low reactivity (i.e. does not substantially react with the synthetic rubber upon heating) can be used, such as coumaron resins such as coumaron indene resins, non-reactive Non-reactive phenol formaldehyde resins such as reactive phenol resins, alkylphenol acetylene resins, terpene/phenol resins, polyterpene resins, petroleum hydrocarbon resins such as hydrocarbon tackifying resins and polybutene, rosin derivatives such as zinc resinate, Mention may be made of mixtures of these. The tackifier is Rubber 1
0.5 to 20 parts by weight, especially 0.5 to 20 parts by weight
It is preferable to mix 1.1 parts by weight of 10 parts by weight.

Furthermore, the polyamide used in the reinforced rubber composition is
Nylon 6, nylon 6, which can be formed into fibers and has a melting point of 150 to 260°C, preferably 190 to 235°C.
10, nylon 12, nylon 611, nylon 612
, nylon 66, and copolymers thereof. The polyamide is not particularly limited as long as it has fiber-forming ability, but it has a number average molecular weight of 5.000 or more, preferably 8.000 or more. If the molecular weight is too low, the fiber forming ability will be poor and the strength will also be low.

The short fibers used in the reinforced rubber composition of the present invention are:
The above-mentioned polyamide fine short fibers have molecules arranged in the fiber axis direction, and have an average diameter of preferably 0.05 to 0.8 mm, especially the shortest fibers with a circular cross section. Preferably, the length is 1 or more.

Further, the silane coupling agent used in the reinforced rubber composition has the structural formula Y-R1SiX3 or Y
A compound represented by -RISiR2X2 is used.

Here, Y, R1, R2, and X each represent the following groups.

HS-C6H5- R1: ApCn H2n BQ Cm
H2m BqC7H24A: C6H4p
= 0~2 n=0~5 B: O, NHQ=O~2 m=o~5 1=0~5 R2: CnH2n+1 n=1N4X
: Dr Cn H2n Es Cm H2m+1D
: O, CfLr=o~2 n=o~5 E: Os=1~2 m=1~5 Specifically, γ-aminopropyltrimethoxysilane, γ
-aminopropyltriethoxysilane, N-β (aminoethyl)γ-aminopropyltrimethoxysilane, N
-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-(diethylenetriamino)propyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(βmethoxyethoxy) Silane, γ-glycidoxypropylmethyljethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-
(3,4 epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-phenyl-γ
-7minopropyltriethoxysilane, N-β(N-vinylbenzylaminoethyl)-γ-amino/propyltrimethoxysilane hydrochloride group, and the like can be suitably used.

Also, the f of polyamide embedded in vulcanizable rubber
ii. The ratio of the weight of vulcanizable rubber to the weight of 411 short fibers (vulcanizable rubber/polyamide fine short fibers) is 10 to 30% by weight, especially 15 to 30% by weight. It is preferable that the polyamide forming the IB fiber and the vulcanizable rubber are bonded via a silane coupling agent.

In this invention, in the reinforced rubber composition used, the strength of the Wt fine short fibers of fiber-formable polyamide embedded in the vulcanizable rubber is high, and furthermore, at the interface of the short fibers, the polyamide and the vulcanizable Because the sulfurable rubber is bonded via a silane coupling agent, a rubber composition with low Mooney viscosity and excellent moldability can be created.Using this composition as a rubber material improves cart/cart resistance. .

Rubber crawlers with good wear resistance can be manufactured.

The above-mentioned reinforced rubber composition used in the present invention is produced, for example, as follows. A vulcanizable rubber, 5 to 100 parts by weight of polyamide per 100 parts by weight of the vulcanizable rubber, and 0.1 to 5.5 mB parts of a silane coupling agent per 100 parts by weight of the polyamide, and optionally the above-mentioned vulcanizable rubber. 0.5 to 20 parts of a tackifier per 100 parts of sulfurable rubber are kneaded at a temperature higher than the melting point of the polyamide, and the resulting kneaded product is extruded at a temperature higher than the melting point of the polyamide. or additionally, optionally by stretching said extrudate at a temperature above or below the melting point of said polyamide.

Furthermore, it can also be obtained by using these stretching methods in combination.

The bead filler rubber composition of the present invention is obtained by blending the above-mentioned reinforced rubber composition (A) with a diene rubber (B) and carbon black (C).

Examples of the diene rubber (B) include natural rubber, polyisoprene, cis-1,4 polybutadiene, styrene-butadiene copolymer rubber, isoprene-isobutylene copolymer, and the like.

The carbon black has a particle size of 10 to 35 m.
#L, dibutyl phthalate (DBP) oil absorption 90-13
0 ml/l OOg is preferably used. Especially N-110 to N-330 as carbon black
is preferably used.

The amount of each of the above components, (I) the polyamide is 1 to 20 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of the total rubber components.
15 parts by weight, (n) (A) component and (B)
) The total proportion of natural rubber and/or polyisoprene in the component is 60 to 100% by weight, preferably 90ffi% or more based on the total rubber component, and (III) the amount of carbon black is 100% by weight of the total rubber component. 30~ for the department
60 parts by weight, preferably 40 to 55 parts by weight, (J
l) The hardness of the vulcanizate measured by JIS K630tA spring type hardness test is 55 to 75°, preferably 65°.
to 75°. If the amount of polyamide (fine short mm) is less than the lower limit, the cut resistance and abrasion resistance of the rubber crawler will decrease, and if it is more than the upper limit, the Mooney viscosity of the compound will increase and the moldability of the rubber crawler will tend to deteriorate. be. If the amount of carbon black is less than the above-mentioned lower limit, the hardness and abrasion resistance of the vulcanizate will decrease, and if it is more than the above-mentioned upper limit, the Mooney viscosity of the composition will become too thick and the moldability of the rubber crawler will tend to deteriorate. If the proportion of rubber is outside the above range, the cut resistance of the vulcanizate will decrease. Furthermore, if the hardness of the vulcanizate is outside the above range, the running properties of the rubber crawler will be reduced.

The rubber composition used in this invention is prepared by mixing the above-mentioned components using a kneading machine such as a Banbury mixer or a roll extruder.
It can be obtained by kneading at 80°C for about 1 to 16 minutes. Additives such as a vulcanizing agent are blended into this rubber composition.

As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxidants, sulfur-containing compounds, etc. can be used. A method of blending a vulcanizing agent into a rubber composition.

There is no particular restriction on the amount, and any known compounding method can be used. Along with vulcanizing agent.

White carbon, activated calcium carbonate, ultrafine magnesium silicate, high styrene resin, coumaron indene resin, phenolic resin, lignin, modified melamine resin,
Reinforcing agents such as petroleum resin, various grades of calcium carbonate,
Fillers such as basic magnesium carbonate, clay, zinc white, diatomaceous earth, recycled rubber, powdered rubber, and ebonite powder;
Vulcanization accelerators such as aldehydes, ammonias, aldehydes/amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, xanthates, vulcanization accelerators such as metal oxides, fatty acids, amines, etc. Aldehydes, amine-ketones, amines, phenols, imidazoles, sulfur-containing or phosphorus-containing anti-aging agents, naphthenic or aromatic process oils, etc. may be blended within the range that does not impair the effects of this invention. A composition can be prepared by The process oil has a low proportion of aromatic type oil which has good mechanical performance of vulcanizate (
0" l 5 phr) may be used, the anti-aging agent is preferably an anti-ozone anti-aging agent in combination with paraffin wax, the total amount may be 1 to 5 phr, the vulcanization system is The rubber crawler of this invention preferably uses a sulfur accelerator (preferably sulfenamide type or thiazole type) and sulfur (slightly large amount is preferable for chip cut resistance). It can be manufactured by combining gold and cord etc. by a method known per se.

[Effects of the present invention] The composition of the present invention has a lower Mooney viscosity than conventional products, so it has excellent moldability.In addition, it has good cut resistance, high tear strength and abrasion resistance, and is superior to conventional products. Instead of a rubber material for rubber crawlers, it can be used for rubber crawlers that mainly run on uneven ground, such as construction vehicles, 73 plowing tractors, tanks, and snowmobiles.

[Examples of the present invention] Examples and comparative examples are shown below. In the following description, parts indicate parts by weight.

In each of the following, the Mooney viscosity of the rubber composition is JZ
According to SK6300, the hardness and tear strength of the vulcanizate are JI
According to SK6301, pico wear is ASTM D2・228
7111 was determined according to the following. Cut resistance is 30X30X2
71111 using a DuPont impact tester with a +m test piece.
Established. However, the angle of the cutting edge of the receiver is 45°, and the diameter is 1.
The weight of the 27 cm, 7B weight was 300 g, and the point at which half of the 10 test pieces were scratched was defined as the breaking point.

In addition, the composition (blending ratio) of the reinforced rubber composition in the following Examples 1 to 10 and Comparative Examples 1 to 4, the composition (l!l! combination ratio) of the rubber Kucorra ff + rubber composition of the present invention, and the rubber crawler of the present invention The physical properties of the rubber composition for use are summarized in Tables 1 and 2 below.

Example 1 100 parts of natural rubber (NR) having a viscosity of 1 x 106 voids and N-(
3-methacryloyloxy-2-hydroxypropyl)
-N" -Phenyl-P-phenylenediamine (trade name Noklar, Ri G-1, manufactured by Ouchi Shinko Kagaku Kogyo Forest) 1.0 part was added, and after kneading them for 30 seconds, nylon 6 (trade name 1030B, Made by Ube Kosanrin, melting point 221°C, molecular weight 30,000) 100 parts by weight, 2 parts by weight of N-β (
51 parts of pellets into which γ-aminopropyltrimethoxysilane (trade name KBM603, Shin-Etsu Chemical Co., Ltd. [9, hereinafter referred to as silane A) had been kneaded were added,
During the 13 minutes of kneading, the temperature inside the Brabender was 23.
Above A) up to 0°C, a crosstalk was obtained. The obtained kneaded material was put into a nozzle with an inner diameter of 2 mm, and the ratio of the length of the nozzle to the inner diameter (L/D).
A 20mmφ extruder with a circular die of 2 (Haake
The extrudate is extruded into a string at a set temperature of 235°C using a drying machine (manufactured by Co., Ltd.), and then the extrudate is passed through a guide roll installed 3 m directly below the nozzle and wound onto a bobbin at a draft ratio of 1θ (speed of 38.8 m/min). I took it. Approximately 500 of these rolls are bundled to form a sheet (approximately 2m+a thick, approximately 150mm wide), and this sheet is placed at a temperature of 60°C with a roll gap of 0.2111m.
A reinforced rubber composition (master bunch) (sample 1) was obtained by rolling the rubber composition about 10 times with a pair of rolling rolls.

Next, using a pan harrier set at 90°C and 77 r, p, m, the vulcanization accelerator,
The blended components except sulfur are kneaded to obtain a mixed material. Next, a vulcanization accelerator and sulfur are kneaded into this kneaded material on a 10-inch roll. After rolling this out into a sheet, it is placed in a mold. and vulcanized to obtain a vulcanized product. Vulcanization was performed at 145° C. for 40 minutes.

Example 2 Vinyltris(β-methoxyethoxy)silane (trade name KBC1003, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of Silane A.
A reinforced rubber composition (sample 2) was obtained in the same manner as in Example 1, except that silane B) was used, and a rubber for rubber crawler was obtained in the same manner as in Example 1, except that Sample 2 was used as the reinforced rubber composition. A composition was obtained.

Example 3 γ-Methacryloxypropyltrimethoxysilane (trade name KBM503, Shin-Etsu Chemical v4) was used instead of Silane A.
A reinforced rubber composition (sample 3) was obtained in the same manner as in Example 1, except that silane C) manufactured by M. Co., Ltd. A rubber composition for use was obtained.

Example 4 A reinforced rubber composition (Sample 4) was prepared in the same manner as in Example 1, except that γ-mercaptopropyltrimethoxysilane (trade name KBM803, Shin-Etsu Chemical Co., Ltd., Silane D) was used in place of Silane A. A rubber composition for a rubber crawler was obtained in the same manner as in Example 1 except that this sample 4 was used as a reinforced rubber composition.

Example 5 β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (trade name KBM303,
A reinforced rubber composition (Sample 5) was obtained in the same manner as in Example 1 except that Silane E) manufactured by Shin-Etsu Chemical Co., Ltd. was used.
A rubber composition for a rubber crawler was obtained in the same manner as in Example 1, except that the following was used as the reinforced rubber composition.

Example 6 Nylon 6 (trade name 1013B, manufactured by Ube Industries, melting point 2)
21 "C!, molecular weight 13,000) Beret 5 pre-mixed with 4 parts by weight of Silane A per 100 parts by weight
A reinforced rubber composition (sample 6) was obtained in the same manner as in Example 1, except that 2 parts were used. A rubber composition was obtained.

Example 7 A reinforced rubber composition (sample 7) was prepared in the same manner as in Example 1 except that the amount of 6-nylon added to the natural rubber was changed to 100 parts.
A rubber composition for a rubber crawler was obtained in the same manner as in Example 1, except that this sample 7 was used as a reinforced rubber composition.

Example 8 A reinforced rubber composition (Sample 8) was obtained in the same manner as in Example 1, except that the amount of 6-nylon added to the natural rubber was changed to 20 parts, and this Sample 8 was used as a reinforced rubber composition. Otherwise, a rubber composition for a rubber crawler was obtained in the same manner as in Example 1.

Examples 9 to 1O A rubber composition for a rubber crawler was obtained in the same manner as in Example 1, except that the composition (blending ratio) of each component was changed as shown in Table 2.

Comparative Examples 1 to 3 Rubber compositions for rubber crawlers were prepared in the same manner as in Example 1, except that the reinforced rubber composition was not used and the composition of each component was changed as shown in Table 2. Obtained.

Comparative Example 4 A rubber composition for a rubber crawler was obtained in the same manner as in Example 1, except that natural rubber and 5 parts of nylon cut fiber were used instead of the reinforced rubber composition. The results are summarized in Table 2.

The amount of bonded rubber in each of Samples 1 to 8 (reinforced rubber compositions) shown in Table 1 was measured as follows.

[Measurement of bonded rubber amount]

2 g of each reinforced rubber composition was added to 200 ml of toluene.
Add at 0°C to dissolve the rubber content in the reinforced rubber composition,
The resulting slurry was centrifuged at room temperature to separate it into a solution portion and a precipitate portion. After repeating the above operation seven times on the precipitated portion, the precipitated portion was dried to obtain nylon m-fiber. This nylon fiber was dissolved in a mixed solvent of phenol and orundichlorobenzene, analyzed by IH nuclear magnetic resonance spectrum (NMR) (internal standard tetramethylsilane), and the NMR chart revealed that methyl groups and methylene groups originating from rubber were found. , 6-co2 due to nylon! ! For each peak of the methylene group adjacent to i, the methylene group adjacent to the NH group, and the other three methylene groups, 9J
The amount of bonded rubber was calculated by determining the molar ratio of 6-nylon and natural rubber using the area method. In addition, the shape of the nylon fibers was adjusted to 10,000 for about 200 fibers.
Measurements were made using a scanning W4 microscope at 0x magnification. The fibers were extremely thin short ta fibers with a circular cross section.

In addition, (Note 1) to (Note 3) in Table 52 are as follows.

(Note 1) BR: Bolibutazinine rubber (UBEPOL-BRI OO1, manufactured by Kosan Corporation) (Note 2) Cut fiber: Nylon short H & fiber diameter 20
JLm, average length 2 mm (Note 3) Other ingredients: 3 parts zinc white, 2 parts stearic acid,

Claims (1)

[Claims] A reinforced rubber in which fine short fibers of polyamide capable of forming fibers are embedded in vulcanizable rubber, and the polyamide and the rubber are bonded via a silane coupling agent. A rubber composition that is a mixture of composition (A), diene rubber (B), and carbon black (C) and that satisfies the following conditions (I) to (IV) may be used as a rubber material. Characteristic rubber crawler. (I) The amount of the polyamide is 1 to 20 parts by weight based on 100 parts by weight of the total rubber components, and (II) The total proportion of natural rubber and/or polyisoprene in components (A) and (B) is 60 for total rubber content
~100% by weight, and (III) the amount of carbon black is 100% by weight of the total rubber component.
(IV) The hardness of the vulcanizate measured by JIS K6301A type spring type hardness test is 55 to 75°.