JP2005200545A - Rubber composition between hose-reinforcing layers and hose using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition between hose-reinforcing layers, obtained by using a butyl rubber, and having excellent strip processability; and to provide the hose obtained by using the rubber composition and having excellent durability and pressure resistance. <P>SOLUTION: The rubber composition between the hose-reinforcing layers is used between the reinforcing layers of the hose, and contains 0.1-2 pts. by mass of aramid short fibers based on 100 pts. by mass of a rubber component containing ≥50 mass% butyl rubber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hose reinforcing interlayer rubber composition used between reinforcing layers of a hose and a hose using the same.

In a hose having a plurality of reinforcing layers, it is known to use a hose reinforcing interlayer rubber between the reinforcing layers in order to bond and fix the reinforcing layers and to prevent rubbing / displacement between the reinforcing layers. As the reinforcing layer, a braided (blade) structure in which reinforcing yarns or wires are braided and a spiral structure in which reinforcing yarns or wires are wound in a spiral shape are generally used.
It is known that the durability and pressure resistance of the hose are improved by using the hose reinforcing interlayer rubber as an intermediate rubber layer (insulation) between the reinforcing layer and the reinforcing layer (for example, Patent Document 1). reference.).

  Further, as such a hose-reinforced interlayer rubber, a characteristic that it is easy to produce a thin sheet used as an intermediate rubber layer during processing (particularly during rolling in a factory) (hereinafter also referred to as “rolling workability”). It is required to have

  However, “the rubber composition used between the reinforcing layers of the hose and characterized by containing a partially crosslinked polymer” described in Patent Document 1 proposed by the present applicant is not yet available. Although the manufacturing processability of the hose during vulcanization is improved, the rolling processability has not been studied.

Japanese Patent Laid-Open No. 10-36564

The present inventor has examined the use of butyl rubber as a hose-reinforced interlayer rubber to satisfy the various requirements described above, but the thin sheet adheres to the roll during rolling using the roll. It has been found that the rolling processability is poor.
Therefore, the present invention provides a hose reinforced interlayer rubber composition having excellent rolling processability using butyl rubber, and further providing a hose having excellent durability and pressure resistance using the rubber composition. And

  As a result of intensive studies to solve the above problems, the present inventors have found that a rubber composition in which aramid short fibers are blended with a rubber component containing a predetermined amount of a butyl rubber is excellent in rolling processability, a hose-reinforced interlayer rubber composition As a result, the present invention has been achieved. That is, the present invention provides a hose reinforced interlayer rubber composition shown in the following (1) and (2) and a hose shown in the following (3).

  (1) A rubber composition used between reinforcing layers of a hose, the hose reinforcing layer containing 0.1 to 2 parts by mass of aramid short fibers with respect to 100 parts by mass of a rubber component containing 50% by mass or more of butyl rubber Rubber composition (first aspect).

(2) The hose-reinforced interlayer rubber composition according to (1), wherein the average length of the aramid short fibers is 0.03 to 5 mm, and the average specific surface area is 7 m ² / g or more.

(3) A hose using an intermediate rubber layer made of the hose reinforced interlayer rubber composition according to (1) or (2) above,
A hose comprising at least an inner rubber layer, an inner reinforcing layer, the intermediate rubber layer, an outer reinforcing layer, and an outer rubber layer in this order from the inner peripheral side (second aspect).

  As described below, according to the present invention, it is possible to provide a hose-reinforced interlayer rubber composition having excellent rolling processability using a butyl rubber, and further, durability and pressure resistance using the rubber composition. This is useful because it is possible to provide a hose having excellent properties.

The present invention will be specifically described below.
The hose-reinforced interlayer rubber composition according to the first aspect of the present invention (hereinafter sometimes referred to simply as “the rubber composition of the present invention”) is a rubber composition used between the reinforcing layers of a hose and is a butyl-based rubber composition. A hose-reinforced interlayer rubber composition containing 0.1 to 2 parts by mass of aramid short fibers with respect to 100 parts by mass of a rubber component containing 50% by mass or more of rubber.
Next, the rubber component and the aramid short fiber forming the rubber composition of the present invention will be described in detail.

<Rubber component>
The rubber component used in the rubber composition of the present invention is a rubber component containing 50% by mass or more, preferably 70% by mass or more of butyl rubber, and may be composed of only butyl rubber.
The butyl rubber constituting the rubber component is not particularly limited as long as it is a butyl rubber. Specific examples thereof include butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), and brominated butyl rubber (Br-IIR). Or brominated isobutylene-p-methylstyrene copolymer (BIMS).
Of these, brominated butyl rubber (Br-IIR) and brominated isobutylene-p-methylstyrene copolymer (BIMS) improve the modulus after crosslinking (vulcanization) of the resulting rubber composition of the present invention. Preferred for reasons.

  In the present invention, such butyl rubber may be used alone or in combination of two or more. When using 2 or more types together, the mixing ratio of the butyl rubbers can be set to any ratio depending on the rolling processability required for the rubber composition of the present invention.

In addition to the butyl rubber, the rubber component may contain other rubber less than 50% by mass, preferably less than 30% by mass.
Specific examples of the other rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), 1,2-butadiene rubber, styrene-butadiene rubber (SBR), and acrylonitrile-butadiene rubber. (NBR), chloroprene rubber (CR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), chlorinated polyethylene rubber (CM), chlorosulfonated polyethylene rubber (CSM), etc. These may be used alone or in combination of two or more. When two or more kinds are used in combination, the mixing ratio of each other rubber can be any ratio depending on the rolling processability required for the rubber composition of the present invention.

<Aramid staple fiber>
The aramid short fiber used in the rubber composition of the present invention is not particularly limited as long as it has an average length of 0.01 to 10 mm. However, the dispersibility in the rubber component and the resulting rubber composition of the present invention are obtained. From the viewpoint of rolling workability, etc., an aramid short fiber having an average length of 0.03 to 5 mm and an average specific surface area of 7 m ² / g or more (hereinafter sometimes simply referred to as “aramid pulp”). Preferably there is. In particular, an aramid pulp having an average length of 0.05 to 3 mm and an average specific surface area of 10 m ² / g or more is more preferable, and the average length is 0.1 to 1.5 mm. More preferably, the aramid pulp has a surface area of 12 m ² / g or more.
Here, the aramid pulp refers to a fiber in which the surface of the fiber is fibrillated (fluffed) by rubbing para-aramid fiber by a predetermined method.

  Specific examples of such aramid short fibers include para-aramid fibers such as polyparaphenylene terephthalamide (PPTA) fiber, copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fiber, and polyparaphenylene. Examples thereof include meta-aramid fibers such as phenylene isophthalamide fibers, and commercially available products include Kevlar 29, Kevlar 49, Kevlar pulp and the like manufactured by DuPont.

Moreover, as said aramid short fiber, you may use a masterbatch with rubber | gum. Here, the master batch is an aramid short fiber / rubber mixture in which aramid short fibers are premixed in rubber by a wet method.
The rubber constituting the masterbatch is not particularly limited, but butadiene rubber (BR), butyl rubber (IIR), ethylene-propylene-diene rubber (EPDM) and the like are preferably used from the viewpoint of compatibility with the rubber component.
If such a master batch is used as the aramid short fiber in order to obtain the rubber composition of the present invention, it is preferable because the dispersibility in the rubber component is good.

  In the present invention, such aramid short fibers may be used alone or in combination of two or more. When using 2 or more types together, the mixing ratio of each aramid short fiber can be an arbitrary ratio depending on the rolling processability required for the rubber composition of the present invention.

The content of the aramid short fibers is 0.1 to 2 parts by mass and preferably 0.3 to 1.8 parts by mass with respect to 100 parts by mass of the rubber component. In addition, when the masterbatch is used as the aramid short fiber, the content of the aramid short fiber in the masterbatch with respect to 100 parts by mass of the whole rubber component including the rubber component and the rubber constituting the masterbatch is used. It is a mass part.
If the content of the aramid short fibers is within this range, it is preferable because the dispersibility in the rubber component is excellent and the rolling processability of the rubber composition of the present invention obtained is excellent.
This is presumably because the viscosity, modulus, and breaking strength of the rubber component are appropriately increased by containing a high hardness aramid short fiber in the rubber component.

  Furthermore, the hose-reinforced interlayer rubber composition according to the first aspect of the present invention includes a filler (reinforcing agent), a plasticizer, a softening agent, an anti-aging agent, an organic activator, a vulcanizing agent, if necessary. Additives such as a vulcanization accelerator and a vulcanization retarder can be blended.

  Specific examples of the filler include fumed silica, calcined silica, precipitated silica, pulverized silica, fused silica, diatomaceous earth and the like; carbon black, white carbon, iron oxide, zinc oxide, titanium oxide , Barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, barium sulfate, wax stone clay, kaolin clay, calcined clay, etc., and these may be used alone or in combination of two or more. Good.

  Specific examples of the plasticizer include dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate, isodecyl succinate, diethylene glycol dibenzoate, pentaerythritol ester, butyl oleate, methyl acetylricinoleate, phosphorus Examples include tricresyl acid, trioctyl phosphate, trimellitic acid ester, propylene glycol adipate polyester, and butylene glycol polyester adipate. These may be used alone or in combination of two or more.

  Specific examples of the softening agent include paraffin oil, process oil, petroleum resin, vegetable oil, liquid rubber and the like, and these may be used alone or in combination of two or more.

  Specific examples of the antioxidant include N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (6PPD), N, N′-dinaphthyl-p-phenylenediamine (DNPD). ), N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD), styrenated phenol (SP), and the like. These may be used alone or in combination of two or more.

  Specific examples of the organic activator include stearic acid, oleic acid, lauric acid, zinc stearate and the like, and these may be used alone or in combination of two or more.

  Specific examples of the vulcanizing agent include sulfur, organic sulfur-containing compounds such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), dipentamethylenethiuram disulfide (DPTT); dicumyl peroxide, and the like. Organic peroxides; metal oxides such as zinc white and magnesia; resins such as phenol resins; quinone dioximes and the like may be used, and these may be used alone or in combination of two or more.

  Specific examples of the vulcanization accelerator include thiazoles such as mercaptobenzothiazole (MBT); sulfenamides such as N-cyclohexyl-2-benzothiazole sulfenamide (CBS); hexamethylenetetramine and the like. Aldehydes and ammonia; guanidines such as diphenylguanidine, and the like. These may be used alone or in combination of two or more.

  Specific examples of the vulcanization retarder include organic acids such as phthalic anhydride, benzoic acid, salicylic acid, and acetylsalicylic acid; N-nitrosodiphenylamine, N-nitrosophenyl-β-naphthylamine, N-nitroso- Nitroso compounds such as polymers of trimethyl-dihydroquinoline; Halides such as trichloromelanin; 2-mercaptobenzimidazole, N-cyclohexylthiophthalimide and the like. These may be used alone or in combination of two or more. May be.

  As described above, such a rubber composition of the present invention is useful because it is excellent in rolling processability, and further, a hose using an intermediate rubber layer made of the rubber composition has durability and durability as described later. This is useful because of its excellent pressure resistance.

  Moreover, the manufacturing method of the rubber composition of this invention is not specifically limited, The said aramid short fiber is contained in the said rubber component, It can manufacture by mix | blending the said additive etc. as needed. Specifically, the rubber component, the aramid short fibers, and the additive compounded as necessary are kneaded using a roll, a kneader, an extruder, a universal stirrer, a twin screw extruder, a Banbury mixer, and the like. The method of manufacturing by doing is illustrated suitably.

The hose according to the second aspect of the present invention (hereinafter sometimes simply referred to as “the hose of the present invention”) is an intermediate rubber layer comprising the above-described hose-reinforced interlayer rubber composition according to the first aspect of the present invention. A hose comprising at least an inner rubber layer, an inner reinforcing layer, the intermediate rubber layer, an outer reinforcing layer, and an outer rubber layer in this order from the inner peripheral side.
Here, an example of a preferred embodiment of the hose of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing the hose of the present invention with a part cut away for each layer. As shown in FIG. 1, a hose 1 is a reinforcing yarn comprising a plurality of reinforcing yarns made of fiber material or a two-layer reinforcing wire wound in a spiral shape between an inner rubber layer 2 and an outer rubber layer 6. Or it embed | buries so that the winding direction of a wire may differ, and the intermediate | middle rubber layer 4 is interposed between the inner side reinforcement layer 3 located in the inner peripheral side of the hose 1, and the outer side reinforcement layer 5 located in the outer peripheral side.
Next, the inner rubber layer, the reinforcing layer (the inner reinforcing layer, the outer reinforcing layer), the intermediate rubber layer, and the outer rubber layer constituting the hose of the present invention will be described in detail.

<Inner rubber layer>
As the inner rubber layer constituting the hose of the present invention, a conventionally known inner rubber layer used for the hose can be used, and it may be formed of one layer alone or a plurality of layers.
The thickness of the inner rubber layer may be any thickness depending on the use of the hose of the present invention, the physical properties required for the hose of the present invention, etc. Degree.

<Reinforcement layer (inner reinforcement layer, outer reinforcement layer)>
As the reinforcing layer (inner reinforcing layer, outer reinforcing layer) constituting the hose of the present invention, a conventionally known reinforcing layer used for the hose can be used. The reinforcing layer embedded is referred to as an inner reinforcing layer, and the reinforcing layer embedded on the outer peripheral side is referred to as an outer reinforcing layer.

  Such an inner reinforcing layer and an outer reinforcing layer may each be of a blade structure or a spiral structure, and may be formed of a single layer or a plurality of layers. Good. Specifically, for example, a braid of braided reinforcing yarn or wire, or a braided reinforcing yarn or wire wound in a spiral shape, in particular, each of the inner reinforcing layer and the outer reinforcing layer is made of reinforcing yarn or wire. When it is formed by being wound in a spiral shape, as shown in FIG. 1, it is preferably embedded so that the winding direction of the reinforcing yarn or wire is different.

<Intermediate rubber layer>
The intermediate rubber layer constituting the hose of the present invention is not particularly limited as long as it is a rubber layer (thin layer sheet) made of the hose reinforced interlayer rubber composition according to the first aspect of the present invention described above. And a rubber layer interposed between the outer reinforcing layer and the outer reinforcing layer.
By using the rubber layer made of the rubber composition of the present invention as an intermediate rubber layer, rubbing / displacement between the inner reinforcing layer and the outer reinforcing layer is prevented, and the durability and pressure resistance of the hose of the present invention obtained are improved. To do. This can prevent rubbing due to the direct contact between the inner reinforcing layer and the outer reinforcing layer by contacting the intermediate rubber layer with the inner reinforcing layer and the outer reinforcing layer. It is thought that it is because it is integrated as a composite.
When the reinforcing layer is composed of three or more layers, the intermediate rubber layer can be used by being interposed between the reinforcing layers.

Although the manufacturing method of the said intermediate | middle rubber layer is not specifically limited, Specifically, the method of making the rubber composition of this invention into a thin layer sheet by the rolling process using a roll under 20-120 degreeC is illustrated suitably. .
The thickness of the intermediate rubber layer can be set to any thickness depending on the use of the hose of the present invention, the physical properties required for the hose of the present invention, etc., but about 0.05 to 5 mm. is there.

<Outer rubber layer>
As the outer rubber layer constituting the hose of the present invention, a conventionally known outer rubber layer used for a hose can be used, and it may be formed of one layer alone or a plurality of layers.
Further, the thickness of the outer rubber layer can be set to any thickness depending on the application in which the hose of the present invention is used, physical properties required for the hose of the present invention, and the like. Degree.

Such a hose of the present invention is useful because it is excellent in durability and pressure resistance as described above. Therefore, the hose of the present invention can be applied to various uses without limiting the application field, but is preferably applied to an automobile air conditioner hose and a power steering hose.
Moreover, the manufacturing method of the hose of this invention is not specifically limited, A conventionally well-known method can be used as a manufacturing method of a hose, Specifically, the said inner surface rubber layer, the said inner side reinforcement layer, the said method on a mandrel After laminating the intermediate rubber, the outer reinforcing layer and the outer rubber layer in this order, the layers are subjected to press vulcanization, steam vulcanization, oven vulcanization (hot air) at 140 to 190 ° C. for 30 to 180 minutes. (Vulcanization) or hot water vulcanization for vulcanization and production.

Hereinafter, the rubber composition and the hose of the present invention will be described in more detail using examples. However, the present invention is not limited to these examples.
(Examples 1-3, Comparative Examples 1 and 2)
Aramid pulp which is aramid short fiber, carbon black (filler), zinc white (vulcanizing agent), stearic acid with composition components (parts by mass) shown in Table 1 below with respect to 100 parts by mass of BIMS which is butyl rubber (Organic activator), paraffin oil (softener) and resin are added and dispersed uniformly with a high viscosity mixing mixer to obtain the hose reinforced interlayer rubber compositions of Examples 1 to 3 and Comparative Examples 1 and 2. It was.

The following components were used as the respective composition components.
・ BIMS: Exxpro 3745 (manufactured by Exxson Chemical)
-Aramid pulp: Rhenogran P91-40EPDM (EPDM / aramid pulp = 60/40 masterbatch, manufactured by Rhein Chemie)
・ Carbon black: Asahi Thermal # 50 (Asahi Carbon Co.)
・ Zinc flower: 3 types of zinc oxide (manufactured by Shodo Chemical Industry Co., Ltd.)
・ Stearic acid: LUNAC YA (manufactured by Kao Corporation)
Paraffin oil: Machine oil 22 (made by Showa Shell Sekiyu KK)
・ Resin: Tack roll 250-I (Taoka Chemical Industries)

  About each obtained rubber composition, the rolling workability and the tensile characteristic were evaluated by the method shown below. The results are shown in Table 1 below.

<Rolling workability>
The evaluation of the rolling processability is performed by putting the unvulcanized product of each obtained rubber composition into a 2 mm thick mold, embossing with a press at 100 ° C. for 5 minutes, and then applying unvulcanized according to JIS K6251-1993. The vulcanized rubber composition was cut into 2 mm-thick dumbbell-shaped test pieces (dumbbell-shaped No. 2) and measured by measuring 50% modulus (M ₅₀ ) [MPa]. (Factory rolling property) was evaluated.
The factory rollability is the one in which each obtained rubber composition is subjected to thin layer sheet production by a roll at the factory, and the one that can produce the thin layer sheet is evaluated as “good” as the rolling processability, and the thin layer sheet cannot be produced. Was evaluated as x as bad rolling workability. Accordingly, it was determined that the 50% modulus of the unvulcanized rubber composition can be evaluated as having excellent rolling workability of the rubber composition when the value is 1.7 MPa or more.

<Tensile properties>
Tensile properties were evaluated for vulcanized rubber compositions obtained by vulcanizing each rubber composition obtained under the conditions of 153 ° C. × 45 minutes immediately after vulcanization (blank) and heat aging (120 ° C. × 7 days standing). ) Went later.
In this evaluation, in accordance with JIS K6251-1993, a vulcanized rubber composition was cut into a dumbbell-shaped test piece (dumbbell-shaped No. 3) having a thickness of 2 mm, 50% modulus (M ₅₀ ) [MPa], and breaking strength. The measurement was performed by measuring (T _B ) [MPa] and elongation at break (E _B ) [%].
The 50% modulus, breaking strength, and breaking elongation are preferably about the same as those of Comparative Example 1, which is a composition of a conventionally known vulcanized rubber composition, because the required characteristics of the hose are satisfied. In particular, the elongation at break in the blank is 100% or more, the elongation at break after heat aging (120 ° C. x 7 days standing) is preferably 80% or more, and if the 50% modulus in the blank is 10 MPa or less, It is preferable because flexibility can be ensured.

  From the results shown in Table 1, the rubber compositions of Examples 1 to 3 have better rolling processability than the rubber composition of Comparative Example 1, and the rubber of Comparative Example 2 containing excess aramid pulp. Since the tensile properties were better than those of the composition, it was revealed that the required properties of the hose were satisfied.

Example 4
A hose using an intermediate rubber layer made of the hose reinforced interlayer rubber composition obtained in Example 1 was prepared as shown below.
An inner rubber layer made of an IIR rubber composition was extruded on a mandrel having an outer diameter of 14 mm to a thickness of 2.0 mm to form an inner tube. Next, a reinforcing yarn made of polyester fiber is spirally wound in one direction on the upper surface to form an inner reinforcing layer, and an unvulcanized material of the hose reinforcing interlayer rubber composition obtained in Example 1 is rolled on the inner reinforcing layer. The processed thin layer sheet was wound to form an intermediate rubber layer. Further, a reinforcing yarn made of the same polyester fiber as above was wound on the intermediate rubber layer in a spiral shape in the opposite direction to the inner reinforcing layer to form an outer reinforcing layer.
Thereafter, an outer rubber layer made of an EPDM rubber composition was extruded on the outer reinforcing layer so as to have a thickness of 1.5 mm, thereby forming an outer tube. Next, ribbon wrapping was performed, and heat vulcanization was performed at about 154 ° C. for 60 minutes using a vulcanizing can, and then unwrapping and mandrel removal were performed to obtain a hose.

(Example 5)
A hose was obtained in the same manner as in Example 4 except that the hose reinforced interlayer rubber composition obtained in Example 2 was used instead of the hose reinforced interlayer rubber composition obtained in Example 1.

(Example 6)
A hose was obtained in the same manner as in Example 4 except that the hose reinforced interlayer rubber composition obtained in Example 3 was used instead of the hose reinforced interlayer rubber composition obtained in Example 1.

(Comparative Example 3)
A hose was obtained in the same manner as in Example 4 except that the hose reinforced interlayer rubber composition obtained in Comparative Example 1 was used instead of the hose reinforced interlayer rubber composition obtained in Example 1.

(Comparative Example 4)
A hose was obtained in the same manner as in Example 4 except that no intermediate rubber layer was formed.

  About each obtained hose, durability and pressure | voltage resistance were evaluated by the method shown below. The results are shown in Table 2 below.

<Durability>
The durability was evaluated by an impact pressure test in accordance with JIS K6330-8: 1998. Using general hydraulic oil (VG46), applying impact repeatedly at 120 ° C and 1.7 MPa, impact until the hose is abnormal (for example, leakage at the fitting, disconnection of the fitting, hose rupture, etc.) The number of times was determined, and the case where no abnormality occurred even after 300,000 impacts was evaluated as ◯, and the others were evaluated as ×.

<Pressure resistance>
The pressure resistance was evaluated by a pressure resistance test in accordance with JIS K6330-2: 1998. Pressurization was performed until ruptured at room temperature (23 ° C.) and a pressure of 7 MPa / min, and the pressure at the time of rupture was measured.

  From the results shown in Table 2, it became clear that the hoses of Examples 4 to 6 using the intermediate rubber layer made of the rubber composition of Examples 1 to 3 are excellent in both durability and pressure resistance.

FIG. 1 is a perspective view showing the hose of the present invention with a part cut away for each layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hose 2 Inner rubber layer 3 Inner reinforcement layer 4 Intermediate rubber layer 5 Outer reinforcement layer 6 Outer rubber layer

Claims (3)

  A rubber composition used between reinforcing layers of a hose, the hose reinforcing interlayer rubber composition containing 0.1 to 2 parts by mass of aramid short fibers with respect to 100 parts by mass of a rubber component containing 50% by mass or more of butyl rubber . ^2. The hose-reinforced interlayer rubber composition according to claim 1, wherein the average length of the aramid short fibers is 0.03 to 5 mm and the average specific surface area is 7 m ² / g or more. A hose using an intermediate rubber layer comprising the hose-reinforced interlayer rubber composition according to claim 1 or 2,
A hose comprising at least an inner rubber layer, an inner reinforcing layer, the intermediate rubber layer, an outer reinforcing layer, and an outer rubber layer in this order from the inner peripheral side.

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