JP5098208B2 - Rubber composition for lift roller and lift roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for rubber rolls, which can give a vulcanized rubber having both abrasion resistance and low heat generation in their compatible state at high levels without deteriorating these characteristics. <P>SOLUTION: This rubber composition for rubber rolls comprises 100 pts.mass of a rubber component comprising styrene-butadiene copolymer rubber and butadiene rubber, 65 to 85 pts.mass of carbon black having a nitrogen adsorption specific surface area of &le;80 m<SP>2</SP>/g, an iodine adsorption of &le;75 mg/g and a DBP absorption of &ge;90 cm<SP>3</SP>/100 g, and a vulcanizing agent in a styrene-butadiene copolymer rubber/butadiene rubber mass ratio of 70/30 to 30/70. The rubber composition for rubber rolls, wherein the physical properties of the composition after vulcanized are in the following (A), (B) and (C) ranges. Therein, (A) JIS-A hardness: 70 to 85, (B) loss tangent: 0.10 to 0.25; (C) abrasion volume per 1,000 rotations of an abrasion wheel measured according to Akron abrasion test of JIS K6264-2-2005: &le;0.02 cm<SP>3</SP>. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a rubber composition for rubber rolls and a rubber roll used for lift rollers, iron-making rollers, and the like.

  Rubber rolls such as lift rollers and iron-making rollers are usually prepared by mixing unvulcanized rubber with fillers such as carbon black, softeners, sulfur-based vulcanizing agents, vulcanizing aids, etc. And after winding the said unvulcanized sheet around an iron core, it vulcanizes | cures in a vulcanization tank, and it manufactures by grind | polishing the surface.

On the other hand, rubber rolls such as lift rollers and iron-making rollers are used with high load and high rotation, and durability is required in addition to appropriate hardness and wear resistance.
For example, Patent Document 1 aims to provide a method for producing a rubber roll having excellent wear resistance and durability, and “a diene-based unvulcanized rubber composition containing a sulfur-based vulcanizing agent”. In a method for producing a rubber roll by vulcanization, a method for producing a rubber roll characterized in that the diene rubber composition contains hexamethylene-1,6-thiosulfate disodium salt is described. . Patent Document 1 describes that the diene-based unvulcanized rubber composition preferably contains carbon black.

JP-A-5-239224

  In recent years, the speed of ski lifts and gondola has been increasing. Especially in the lifts used in the summer tourist season, the lift rollers are affected by friction with wires, internal heat generation due to rubber distortion, direct sunlight, etc. The problem of generating heat began. Therefore, development of a rubber composition having not only wear resistance and the like but also a property (low heat generation property) capable of suppressing heat generation is desired.

However, with the method described in Patent Document 1, it has been difficult to produce a lift roller that can satisfy these characteristics at a high level without impairing both wear resistance and low heat build-up.

Accordingly, an object of the present invention is to provide a rubber composition for a lift roller that can obtain a vulcanized rubber that can satisfy both of these characteristics at a high level without impairing both wear resistance and low heat build-up. .
Another object of the present invention is to provide a lift roller that can achieve both of these characteristics at a high level without impairing both wear resistance and low heat generation.

The inventor has a rubber component containing a specific proportion of styrene-butadiene copolymer rubber and butadiene rubber, a nitrogen adsorption specific surface area of 80 m ² / g or less, an iodine adsorption amount of 60 to 75 mg / g, When absorption amount containing a carbon black is 90cm ^3/100 g or more at a specific ratio, to obtain a vulcanized rubber which can both these properties at a high level without compromising any of the abrasion resistance and low heat build-up It was found that the rubber composition for a lift roller can be obtained .
The present inventor has completed the present invention based on this finding.

That is, the present invention provides the following (1) to ( 5 ).
(1) 100 parts by mass of a rubber component containing styrene-butadiene copolymer rubber and butadiene rubber;
Nitrogen adsorption specific surface area of not more than 80 m ² / g, a iodine adsorption amount 60 to 75 mg / g, carbon black 65-85 parts by weight is DBP absorption 90cm ^3/100 g or more,
Containing vulcanizing agents,
A rubber composition for a lift roller , wherein a mass ratio of the styrene-butadiene copolymer rubber and the butadiene rubber is 70/30 to 30/70 .
(2 ) The rubber composition for a lift roller according to (1 ), further containing a lubricant.
(3) The rubber composition for a lift roller according to (2), wherein the content of the lubricant is 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component.
( 4 ) The rubber composition for lift rollers according to (2) or (3) above, wherein the lubricant is an unsaturated fatty acid salt.
( 5 ) A lift roller having a ring core and a rubber layer made of a vulcanized product of the rubber composition for a lift roller according to any one of the above (1) to ( 4 ) covering the outer peripheral surface of the ring core.

The rubber composition for lift rollers of the present invention (hereinafter also referred to as “rubber composition for rubber roll”) is a vulcanized rubber capable of satisfying these characteristics at a high level without impairing both wear resistance and low heat build-up. Can be obtained.
Further, the lift roller of the present invention (hereinafter also referred to as “rubber roll”) can achieve both of these characteristics at a high level without impairing both wear resistance and low heat generation.

Hereinafter, the present invention will be described in more detail.
The first aspect of the rubber composition for rubber rolls of the present invention (hereinafter referred to as “the composition of the first aspect”) includes 100 parts by mass of a rubber component containing styrene-butadiene copolymer rubber and butadiene rubber, and a nitrogen adsorption ratio. surface area is not more than 80 m ² / g, and the iodine adsorption amount 75 mg / g or less, and carbon black 65-85 parts by DBP absorption amount is 90cm ^3/100 g or more, and containing a vulcanizing agent, the A rubber composition for a rubber roll having a mass ratio of styrene-butadiene copolymer rubber and the butadiene rubber of 70/30 to 30/70.

<Rubber component>
The rubber component includes styrene-butadiene copolymer rubber (SBR) and butadiene rubber (BR), and the mass ratio of SBR to BR (SBR / BR) is 70/30 to 30/70. Since the rubber component contains SBR and BR, the vulcanized product of the composition of the first aspect is excellent in wear resistance.
Moreover, since the mass ratio (SBR / BR) between SBR and BR is 70/30 to 30/70, the balance of wear resistance, cold resistance, strength characteristics, and workability is excellent. In view of these characteristics, the mass ratio between SBR and BR (SBR / BR) is preferably 70/30 to 50/50.

  In addition to SBR and BR, the rubber component can contain other rubbers as long as the effects of the present invention are not impaired. Examples of other rubbers include acrylonitrile butadiene copolymer rubber (NBR), isoprene rubber (IR), natural rubber (NR), and isobutylene isoprene copolymer rubber (IIR). These may be used alone or in combination of two or more.

<Carbon black>
The carbon black used for the composition of the first aspect has the following properties (i) to (iii).

(I) nitrogen adsorption specific surface area is not more than 80 m ² / g, preferably not more than ^{75m 2 / g, 70m 2 /} g or less is more preferable. Within this range, the vulcanized composition will be excellent in low exothermic properties. Further, from the viewpoint of excellent wear resistance, the nitrogen adsorption specific surface area is preferably 55 m ² / g or more, and more preferably 60 m ² / g or more.
The nitrogen adsorption specific surface area refers to the specific surface area obtained by the nitrogen adsorption method. Usually, the smaller this value, the larger the particle size of the carbon black.
In this specification, the nitrogen adsorption specific surface area is measured according to JIS K6217-2-2001.

(Ii) The iodine adsorption amount is 75 mg / g or less, and preferably 72 mg / g or less. Within this range, the vulcanized composition will be excellent in low exothermic properties. From the viewpoint of excellent abrasion resistance, iodine adsorption amount, 60 mg / g or more der is, it is favorable preferable is 65 mg / g or more.
In this specification, the iodine adsorption amount is measured according to JIS K6217-1-2001.

(Iii) DBP absorption is at 90cm ^3/100 g or more, 100 cm ^3/100 g or more is more preferable. Within this range, the vulcanized composition will have excellent wear resistance and mechanical properties. Further, from the viewpoint of excellent low heat build-up, DBP absorption amount is preferably 120 cm ^3/100 g or less, and more preferably less 110 cm ^3/100 g.
The DBP absorption is a measure of the ability of carbon black to absorb liquid (DBP), and the larger the value, the larger the carbon black structure.
In this specification, the DBP absorption is measured according to JIS K6217-4-2001.

  Content of the said carbon black is 65-85 mass parts with respect to 100 mass parts of said rubber components. Within this range, the vulcanized composition is excellent in wear resistance and low heat build-up. The content of the carbon black is preferably 65 to 80 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of providing these characteristics with a good balance.

  A commercial item can also be used as said carbon black. Examples of commercially available products include Show Black N330T (manufactured by Cabot Japan), Niteron # 200 (manufactured by Nippon Kayaku Carbon), and the like.

<Vulcanizing agent>
The vulcanizing agent is not particularly limited as long as it is a sulfur vulcanizing agent. Specifically, for example, sulfur generally used as a vulcanizing agent for rubber such as powdered sulfur, highly dispersible sulfur, insoluble sulfur and the like. Is mentioned.
The content of the vulcanizing agent is not particularly limited, but is preferably 1.5 to 4.5 parts by mass with respect to 100 parts by mass of the rubber component, and 2.0 to 3 in terms of easily obtaining desired characteristics. More preferably, 5 parts by mass.

<Vulcanization accelerator>
The composition of the first embodiment preferably further contains a vulcanization accelerator. By using in combination with the above vulcanizing agent, a high-strength rubber roll can be obtained.
As the vulcanization accelerator, a normal sulfur vulcanization accelerator can be used. Specifically, for example, thiazoles such as mercaptobenzothiazole (MBT) and dibenzothiazyl disulfide (MBTS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), Nt-butyl-2-benzo Sulfenamides such as thiazole sulfenamide (BBS), thiurams such as tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTM), aldehydes and ammonia such as hexamethylenetetramine (H), diphenyl group Examples thereof include guanidines such as andin (DPG), metal oxides such as zinc oxide, and fatty acids such as stearic acid. These may be used alone or in combination of two or more.

  The content of the vulcanization accelerator is preferably 0.5 to 2.0 parts by mass and more preferably 0.8 to 1.5 parts by mass with respect to 100 parts by mass of the rubber component.

<Lubricant>
The composition of the first embodiment preferably further contains a lubricant. When a lubricant is contained, a vulcanized rubber having more excellent wear resistance can be obtained.
Examples of the lubricant include unsaturated fatty acid salts, saturated fatty acid salts, unsaturated fatty acid esters, and saturated fatty acid esters. These may be used alone or in combination of two or more.
Among these, unsaturated fatty acid salts are preferable from the viewpoint of excellent wear resistance.

  Specific examples of the unsaturated fatty acid salt include various metals such as aluminum, sodium, strontium, magnesium, calcium, and zinc of unsaturated fatty acids having 4 to 22 carbon atoms such as oleic acid, linolenic acid, and linoleic acid. Examples thereof include salts and mixtures thereof.

  Specific examples of the saturated fatty acid salt include various metal salts such as aluminum, sodium, strontium, magnesium, calcium, and zinc of higher saturated fatty acids having 4 to 22 carbon atoms such as palmitic acid, stearic acid, and myristic acid. And mixtures thereof.

  2-10 mass parts is preferable with respect to 100 mass parts of said rubber components, and, as for content of the said lubricating material, 2-5 mass parts is more preferable. Within this range, the wear resistance of the vulcanized rubber can be improved and the hardness will not be too low.

  The composition of the first aspect is a plasticizer, a softening agent, an anti-aging agent, a tackifier, a filler, and a silane coupling as long as the effects of the present invention are not impaired in addition to the above-described components. An agent etc. can be contained.

  The method for producing the composition of the first aspect is not particularly limited. For example, the rubber component, the carbon black, the vulcanizing agent, and, if necessary, the lubricant and various additives are stirred with a Banbury mixer. Can be obtained by dispersing.

Next, the second aspect of the rubber composition for rubber rolls of the present invention (hereinafter referred to as “the composition of the second aspect”) will be described in detail.
The composition of the second aspect has physical properties after vulcanization, (A) JIS-A hardness is 70 to 85, and (B) loss tangent (tan δ) is 0.10 to 0.26. (C) The wear volume per 1000 revolutions of the wear wheel (hereinafter also referred to as “Aklon A”) measured in accordance with the Akron wear test (Method A) of JIS K626264-2-2005 is 0.02 cm ³ or less. A rubber composition for a rubber roll.
The test conditions of Akron A are 15 degrees of inclination between the test piece and the wear wheel, a load 27N applied to the wear wheel, and the rotation speed of the test piece is 75 ± 5 times per minute.

When the JIS-A hardness of the vulcanized rubber obtained by vulcanizing the composition of the second aspect is 70 to 85, it is suitably used for rubber rolls such as lift rollers and iron-making rollers used at high loads and high rotations. Can be used. The JIS-A hardness is preferably 73 to 85, and more preferably 75 to 85.
In the present specification, the JIS-A hardness is measured at a test temperature of 23 ° C. according to JIS K6253-1997.

If tan δ of the vulcanized rubber obtained by vulcanizing the composition of the second aspect is 0.10 to 0.26, the vulcanized rubber obtained by vulcanizing the composition of the second aspect is excellent in low It can exhibit exothermic properties and can be suitably used for rubber rolls such as lift rollers and iron-making rollers that are used at high loads and high rotations. From the standpoint of superior exothermic properties, tan δ after vulcanization is preferably 0.10 to 0.23, and more preferably 0.10 to 0.21.
In this specification, tan δ is 10% stretched at a measurement temperature of 20 ° C. using a viscoelastic spectrometer (Rheograph-Solid, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and vibration with an amplitude of ± 2% is a frequency. Measured by giving at 20 Hz.

(C) If Akron A of the vulcanized rubber obtained by vulcanizing the composition of the second aspect is 0.02 cm ³ or less, it can exhibit excellent wear resistance and is used under high load and high rotation. It can be suitably used for rubber rolls such as lift rollers and iron-making rollers. From the viewpoint of excellent by abrasion resistance, Akron A after vulcanization is preferably 0.015 cm ³ or less, 0.01 cm ³ or less is more preferable.

  In the composition of the second aspect, the 100% modulus after vulcanization is preferably 12 MPa or less, and more preferably 5.0 to 9.0 MPa. Further, the breaking strength after vulcanization is preferably 15 MPa or more, more preferably 17 MPa or more. Further, the elongation at break after vulcanization is preferably 150% or more, and more preferably 200% or more.

  The composition of the second aspect is not particularly limited as long as the physical properties after vulcanization satisfy all the above conditions (A) to (C), but the rubber composition for rubber rolls is not particularly limited. The composition of the first aspect is preferably exemplified.

Next, the rubber roll of the present invention will be described in detail.
The rubber roll of the present invention is a rubber roll having a ring core and a rubber layer made of a vulcanized product of the rubber composition for a rubber roll of the present invention covering the outer peripheral surface of the ring core.
Hereinafter, an example of the rubber roll of the present invention will be described with reference to the drawings. However, the present invention is not limited to this.

FIG. 1 is a conceptual diagram of a rubber roll 1 using the rubber composition for a rubber roll of the present invention, FIG. 2 is a sectional view of the rubber roll 1 cut along AA shown in FIG. 1, and FIG. FIG. 6 is a cross-sectional view of layer 5.
As shown in FIGS. 1 and 2, the rubber roll 1 has a roller pin 3 at the center of the circle of the ring core 2, a flange 4 around the ring core 2, and the outer peripheral surface of the ring core 2 and the flange. 4 has a rubber layer 5 made of a vulcanized product of the rubber composition for a rubber roll according to the present invention.

  The ring core 2 may be similar in size, shape, material, etc. to known rubber rolls, and is not particularly limited. However, as shown in FIG. 2, the center and periphery of the circle are thick, and the center and periphery are It is preferable that the gap is thin because the rubber roll 1 can be reduced in weight and manufactured at low cost. Moreover, it is preferable that the ring core 2 is comprised from metals, such as iron and stainless steel, from the point of being excellent in intensity | strength.

  The roller pin 3 serves as a rotation axis of the rubber roll 1. The size, shape, material, and the like may be the same as those of known rubber rolls, and are not particularly limited.

  The flange 4 is provided around the ring core 2, and the inner surfaces of the two flanges 4 are in close contact with the side surfaces of the rubber layer 5 to protect the rubber layer 5 as shown in FIG. 2. The size, shape, material, and the like may be the same as those of known rubber rolls, and are not particularly limited.

As shown in FIG. 3, the rubber layer 5 includes a vulcanized rubber 6 and, if necessary, a reinforcing layer 7.
The vulcanized rubber 6 is a vulcanized product of the rubber composition for a rubber roll of the present invention. The size, shape, material and the like may be the same as those of a known rubber roll, and are not particularly limited. The vulcanization conditions are not particularly limited and can be set as appropriate.
Moreover, as shown in FIG. 3, it is preferable that the rubber layer 5 has a dent in the surface which contacts a wire from the point which can prevent the shift | offset | difference of the wire which contacted the rubber layer 5.
The reinforcing layer 7 may be the same as that used for a known rubber roll, and is not particularly limited. For example, a polyester cloth or a nylon cloth is preferable. The reinforcing layer 7 may be one layer or two or more layers. The reinforcing layer 7 is provided on the side closer to the surface in contact with the ring core 2 than the center in the thickness direction of the rubber layer 5 because the reinforcing layer 7 is not easily exposed on the surface even when the vulcanized rubber 6 is worn. Is preferred.

  The method for producing the rubber roll of the present invention is not particularly limited. For example, the rubber composition for a rubber roll of the present invention is dispensed with a calender roll or the like to obtain a sheet-like unvulcanized rubber composition. The rubber roll of the present invention can be obtained by winding the vulcanized rubber composition around the ring core until a desired thickness is obtained, followed by vulcanization and then polishing the surface of the vulcanized rubber.

  The above-described rubber roll of the present invention can achieve both wear resistance and low heat buildup, which cannot be achieved by conventional rubber rolls, by using the rubber composition for a rubber roll of the present invention. It can be used for rubber rolls for iron-making rollers, rubber rolls for paper-making, and the like, and can be particularly suitably used for lift rollers.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Examples 1-6 and Comparative Examples 1-3>
Each component shown in the following Table 1 was mixed using a stirrer with the composition (parts by mass) shown in Table 1 to obtain each composition shown in Table 1.
Each composition obtained was vulcanized by heating at 148 ° C. for 30 minutes. The obtained vulcanized rubber was measured for JIS-A hardness, 100% modulus, breaking strength, breaking elongation, tan δ and Akron A by the following methods.
The results are shown in Table 1.

(JIS-A hardness)
According to JIS K6253-1997, the JIS-A hardness of the vulcanized rubber of each composition was measured at 23 ° C.

(100% modulus, breaking strength, breaking elongation)
The vulcanized rubber of each composition was cut into a dumbbell shape having a thickness of 2 mm (dumbbell shape No. 3) to obtain a test piece. According to JIS K6251-1993, 100% modulus (MPa), breaking strength (MPa) and breaking elongation (%) were measured.

(Tan δ)
Vulcanized rubber of each composition was cut into strips having a length of 40 mm, a width of 5 mm, and a thickness of 2 mm to obtain test specimens.
Each specimen was stretched 10% using a viscoelastic spectrometer at a measurement temperature of 20 ° C., and a vibration with an amplitude of ± 2% was applied at a frequency of 20 Hz, and tan δ was measured.
In addition, it can be said that it is excellent in low exothermic property, so that tan-delta is small.

(Akron A)
For the vulcanized rubber of each composition, the inclination angle between the test piece and the wear wheel is 15 degrees, the load applied to the wear wheel is 27 N, and the rotation of the test piece, in accordance with the AKRON wear test (Method A) of JIS K6264-22005. The wear volume (cm ³ ) per 1000 revolutions of the wear wheel was measured under the condition of 75 ± 5 speeds per minute.
In addition, it can be said that it is excellent in abrasion resistance, so that Akron A is small.

Each component shown in Table 1 is as follows.
SBR: NIPOL 1502, manufactured by Nippon Zeon Co., Ltd. BR: NIPOL 1220, manufactured by Nippon Zeon Co., Ltd. Carbon black (HAF1): Show Black N339M, manufactured by Cabot Japan, Nitrogen adsorption specific surface area 81 m ² / g, iodine adsorption amount 91 mg / g, DBP absorption 122cm ³ / 100g
Carbon black (HAF2): Show black N330T, Cabot Japan KK, nitrogen adsorption specific surface area of 65m ² / g, iodine adsorption amount of 71mg / g, DBP absorption amount of 104cm ³ / 100g
・ White carbon: Nip seal AQ, manufactured by Tosoh Corporation ・ Zinc oxide: Three types of zinc oxide, manufactured by Shodo Chemical Industry Co., Ltd. ・ Stearic acid: Beads stearic acid YR, manufactured by NOF Corporation ・ Wax: Suntite R, manufactured by Seiko Chemical Co., Ltd. Ingredients: Zinc soap mixture of high molecular weight fatty acids, Stractol A50P, SCHILL & SEILACHER GMBH & CO. • Anti-aging agent: Santoflex 6PPD, manufactured by Flexis • Silane coupling agent: SI69, manufactured by Degussa • Aroma oil: Extract No. 4, manufactured by Showa Shell Sekiyu KK • Sulfur: Oil-treated sulfur, Karuizawa Refinery・ Vulcanization accelerator: N-cyclohexyl-2-benzothiazolylsulfenamide, Noxeller CZ, manufactured by Ouchi Shinsei Chemical Co., Ltd.

As is clear from the results shown in Table 1 above, the vulcanized rubber of the composition (Comparative Example 1) containing 70 parts by mass of carbon black (HAF1) with respect to the rubber component 100 is excellent in low heat buildup. However, the wear resistance was poor. In contrast to Comparative Example 1, the vulcanized rubber of the composition (Comparative Example 2) containing 80 parts by mass of carbon black (HAF1) with respect to 100 parts by mass of the rubber component was excellent in wear resistance. However, the low exothermicity was bad. Further, the vulcanized rubber of the composition (Comparative Example 3) containing 60 parts by mass of carbon black (HAF2) with respect to 100 parts by mass of the rubber component is excellent in low heat build-up because the content of carbon black is small. However, the hardness and wear resistance were low.
On the other hand, the vulcanized rubbers of the compositions of Examples 1 to 6 were compatible with both low heat buildup and wear resistance at a high level.

FIG. 1 is a conceptual diagram of a rubber roll 1 using the rubber composition for a rubber roll of the present invention. FIG. 2 is a cross-sectional view of the rubber roll 1 cut along AA shown in FIG. FIG. 3 is a cross-sectional view of the rubber layer 5.

Explanation of symbols

1 Rubber Roll 2 Wheel Core 3 Roller Pin 4 Flange 5 Rubber Layer 6 Vulcanized Rubber 7 Reinforcement Layer

Claims (5)

100 parts by mass of a rubber component containing styrene-butadiene copolymer rubber and butadiene rubber;
Nitrogen adsorption specific surface area of not more than 80 m ² / g, a iodine adsorption amount 60 to 75 mg / g, carbon black 65-85 parts by weight is DBP absorption 90cm ^3/100 g or more,
Containing vulcanizing agents,
A rubber composition for a lift roller , wherein a mass ratio of the styrene-butadiene copolymer rubber and the butadiene rubber is 70/30 to 30/70. The rubber composition for a lift roller according to claim 1, further comprising a lubricant.   The lift roller rubber composition according to claim 2, wherein the content of the lubricant is 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition for a lift roller according to claim 2 or 3 , wherein the lubricant is an unsaturated fatty acid salt. Lift roller having a wheel core, a rubber layer formed of vulcanizate of the lift roller rubber composition according to any one of claims 1 to 4 which covers the outer peripheral surface of said wheel core.

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