JP2013155270A - Rubber composition for hose and hose using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a hose, which can reduce an insertion load of a hose fitting without using an insertion aid, and further can solve the problem of slipping off of a hose or the like after assembly, and to provide a hose using the same.SOLUTION: A rubber composition for a hose includes following (A), as a rubber component, and following (B) to (D) components wherein the content of the (B) component is 0.5-10 pts.wt to 100 pts.wt of the (A) component. An innermost layer of the hose is formed by using the composition: (A) an ethylene-propylene-diene ternary copolymer rubber (EPDM); (B) a plasticizer having an SP value of ≥9.2; (C) a carbon black having a DBP oil absorption amount of ≥100 ml/100g; and (D) a crosslinking agent.

Description

  The present invention relates to a rubber composition for a hose and a hose using the same, and more specifically, a rubber composition for a hose used for a hose excellent in assembling with an apparatus such as an engine, and the same. It relates to hoses.

  2. Description of the Related Art Conventionally, hoses used in automobiles and the like are often formed with rubber at the innermost layer in order to ensure sealing properties when assembled to a hose base. Such a hose usually has a laminated structure. For example, in order to improve the pressure resistance, durability, etc. of the hose, a nylon fiber, an aromatic polyamide fiber, a polyester is provided between the outer peripheral surface and the interlayer of the hose. A reinforcing yarn layer formed by braiding reinforcing yarns made of fibers or the like is laminated.

  The hose is usually attached to each device in the engine room by inserting a substantially cylindrical hose base provided in each device into an end opening of the hose.

  When the hose is attached as described above, an insertion aid (lubricating oil) is applied to the outer peripheral surface of the hose base or the inner peripheral surface of the hose end opening in order to reduce the insertion load of the hose. (For example, refer to Patent Document 1).

JP 58-187688 A

  However, when the insertion aid is used as described above, the problem is that after insertion, the insertion aid remaining between the hose base outer peripheral surface and the hose inner peripheral surface makes it easy for the hose to come off or slip out of the base. May occur. In particular, since strong vibration is generated in the engine room, the vibration tends to apply a strong tensile force to the hose, and the above-described hose disconnection is likely to occur. Furthermore, the use of an insertion aid may be troublesome because it takes extra man-hours, including managing the amount of application. For this reason, in situations where these are problems, the hose is attached without using an insertion aid.

  However, radiator hoses, heater hoses, turbo air hoses, fuel hoses that require pressure resistance, etc., as described above, usually have a reinforcing yarn layer in order to increase pressure resistance. In many cases, it is difficult to insert the base. Even if the insertion is tight (the insertion load is large), it is necessary to force the insertion work without using an insertion aid at the location where the hose is likely to come off as described above. There are concerns about deterioration in assembly work efficiency and health hazards to workers. Therefore, it is also considered to design the hose side so that the knitting angle of the reinforcing yarn constituting the reinforcing yarn layer is reduced and the diameter of the hose is easily expanded when the base is inserted. When the knitting angle of the reinforcing yarn is reduced, the contraction force of the expanded hose opening is reduced and the hose connectivity is deteriorated, so that the hose is likely to come off. In addition, when the knitting angle of the reinforcing yarn is reduced, the hose reinforcing effect by the reinforcing yarn layer is also reduced, so that the hose expands and deforms in the radial direction as the internal pressure in the hose increases, which causes a problem in hose performance. Therefore, there is a demand for a technique for improving the insertion property of the hose base without changing the knitting angle of the reinforcing yarn to be small.

  The present invention has been made in view of such circumstances, and can reduce the insertion load of the hose base without using an insertion aid, and also eliminate problems such as hose disconnection after assembly. It is an object of the present invention to provide a rubber composition for a hose that can be used, and a hose using the same.

In order to achieve the above object, the present invention is a rubber composition for a hose containing the following (A) as a rubber component and the following (B) to (D) components: A rubber composition for a hose in which the content of the component (B) is 0.5 to 10 parts by weight with respect to 100 parts by weight of the component is a first gist.
(A) Ethylene-propylene-diene terpolymer rubber (EPDM).
(B) A plasticizer having an SP value of 9.2 or more.
(C) Carbon black having a DBP oil absorption of 100 ml / 100 g or more.
(D) Crosslinking agent.

  Moreover, this invention makes the 2nd summary the hose which the innermost layer of a hose consists of the rubber composition for hoses of the said 1st summary.

  That is, the present inventor has intensively studied to solve the above problems. In the course of the research, the present inventor used ethylene-propylene-diene terpolymer rubber (EPDM) excellent in water resistance, heat resistance, etc. for the rubber composition for forming the innermost layer of the hose. Therefore, it was studied to reduce the insertion load without applying an insertion aid by previously containing a substance that reduces the frictional force. As a specific method, the inventor has conceived that a plasticizer is added to the rubber composition, this is intentionally bleed, and the inner peripheral surface of the hose is self-lubricated. However, in order to intentionally bleed, it is necessary to add a large amount of plasticizer or the like, or to select a plasticizer that easily bleeds, which reduces rubber properties (such as compression set) and hose. There is a risk of impairing the sealing performance. Moreover, when there are too many said bleeds, there also exists a problem of an external appearance defect. On the contrary, if the bleed is too small, the effect of reducing the frictional force cannot be obtained, so that adjustment is difficult. As a result of further experiments by the present inventor in consideration of these things, a specific amount of plasticizer having an SP value of 9.2 or more (0.5 to 10 parts by weight with respect to 100 parts by weight of EPDM) is added to EPDM. Furthermore, when carbon black having a DBP oil absorption of 100 ml / 100 g or more was blended, it was found that the intended purpose could be achieved, and the present invention was achieved.

  More specifically, in the present invention, the plasticizer compounded in the rubber composition is generally close to the SP value of the polymer. In the present invention, the plasticizer is far away from the SP value of the polymer EPDM (SP A plasticizer (with a value of 9.2 or more) is used to facilitate intentionally bleeding and reduce the insertion load of the hose base. At the same time, the rubber composition for a hose of the present invention contains carbon black having a DBP oil absorption of 100 ml / 100 g or more. The plasticizer remaining between the inner peripheral surface and the inner peripheral surface is absorbed and removed, so that a sufficient fastening force can be obtained. As a result, the problem that the hose tends to come off and shift from the base due to vibration or the like is solved. Will come to be.

  As described above, the rubber composition for a hose of the present invention contains EPDM, a plasticizer having an SP value of 9.2 or more, carbon black having a DBP oil absorption of 100 ml / 100 g or more, and a crosslinking agent. The content ratio of the plasticizer is set within a specific range. Therefore, when the rubber composition for a hose of the present invention is used for, for example, the innermost layer forming application of a hose, it is excellent in water resistance, heat resistance, sealability, etc., and an insertion aid is applied by bleeding of the plasticizer. Even if it is not, the insertion load of the hose base can be reduced. As a result, the assembly work (insertion work) of the hose is facilitated, and furthermore, the operation cost can be suppressed because the application amount management of the insertion aid and the like becomes unnecessary. Further, when the rubber composition is used for forming the innermost layer of the hose, the plasticizer that has bleed on the inner peripheral surface of the hose is absorbed and removed over time after the hose is assembled. Such problems can be solved. Therefore, the above-mentioned hose improves the workability of assembling at locations where strong vibrations occur (locations where insertion aids could not be used due to concerns about hose removal after assembly), such as in the engine room. Can contribute greatly.

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

  The rubber composition for hose of the present invention (hereinafter sometimes referred to as “rubber composition”) includes an ethylene-propylene-diene terpolymer rubber (EPDM) (component A) and a specific plasticizer (component B). ), Specific carbon black (C component), and a crosslinking agent (D component), and the content ratio of the plasticizer of the B component is set in a specific range. Below, each said component is demonstrated.

<< EPDM (A component) >>
As the EPDM (component A) used in the rubber composition for a hose of the present invention, the diene monomer (third component) is preferably a diene monomer having 5 to 20 carbon atoms, specifically, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and the like. Among these diene monomers (third component), dicyclopentadiene (DCP) and 5-ethylidene-2-norbornene (ENB) are preferable.

  If necessary, ethylene-propylene copolymer rubber (EPM) can be blended and used together with EPDM.

<< Specific plasticizer (component B) >>
As the specific plasticizer (component B) used together with the EPDM, a plasticizer having an SP value of 9.2 or more is used. That is, if the SP value of the plasticizer is too low, it will approach the SP value of EPDM (component A), so that intentional bleeding of the plasticizer hardly occurs, and the frictional effect is reduced (reducing the insertion load of the hose base). This is because (effect) cannot be obtained.

  The SP value of the plasticizer is preferably in the range of 9.2 to 10.2, and more preferably in the range of 9.2 to 9.9. That is, if the SP value is too lower than the above range, the effect of reducing the insertion load of the hose base cannot be effectively obtained. Conversely, if the SP value exceeds the above range, the plasticizer is excessively bleed, This is because there is a possibility that problems such as deterioration of physical properties of rubber and hose disconnection after assembly may occur.

  Here, the SP value is also called a solubility parameter, and is an index indicating the polarity of a substance, and can be obtained by the following formula (1).

  Specific examples of the specific plasticizer (component B) include dibutyl phthalate, octylbenzyl phthalate, nonylbenzyl phthalate, dipropylene glycol dibenzoate, tricresyl phosphate, butylbenzyl phthalate, and the like. These may be used alone or in combination of two or more.

  Content of the said specific plasticizer (B component) exists in the range of 0.5-10 weight part with respect to 100 weight part of EPDM (A component), Preferably it is 2-7 weight part. That is, if the content of the plasticizer of the B component is too small, intentional bleeding of the plasticizer is difficult to occur, and the effect of reducing the frictional force (the effect of reducing the insertion load of the hose base) cannot be obtained. On the other hand, if the content of the plasticizer of component B is too large, problems such as poor appearance due to excessive bleeding, and deterioration of the sealing properties of the hose due to a decrease in rubber physical properties (such as compression set) are observed. Because it becomes like this.

《Specific carbon black (C component)》
As the specific carbon black (component C) used with the EPDM and the plasticizer, carbon black having a DBP oil absorption of 100 ml / 100 g or more is used. That is, since the above-mentioned specific carbon black absorbs the bleed plasticizer (component B), the plasticizer intentionally bleed to reduce the insertion load of the hose base (the hose base outer peripheral surface and the hose) The plasticizer remaining between the inner peripheral surface and the inner peripheral surface can be absorbed and removed. As a result, it is possible to solve the problem that the hose is likely to come off or shift from the base due to vibration or the like. The DBP oil absorption is a value measured according to JIS K 6217 (Method A).

  The DBP oil absorption amount of the carbon black is preferably in the range of 100 to 160 ml / 100 g, more preferably in the range of 100 to 140 ml / 100 g. That is, if the DBP oil absorption amount of carbon black is too lower than the above range, the plasticizer remaining between the hose base outer peripheral surface and the hose inner peripheral surface cannot be sufficiently absorbed and removed, resulting in vibration or the like. This is because the hose may come off or shift from the base, and conversely, if the DBP oil absorption amount of the carbon black exceeds the above range, the bleed may be insufficient.

  The content of the specific carbon black is preferably 50 to 190 parts by weight, particularly preferably 80 to 160 parts by weight, and most preferably 100 to 140 parts by weight with respect to 100 parts by weight of EPDM (component A). That is, if the content of the specific carbon black is too small, the plasticizer intentionally bleed to reduce the insertion load of the hose base (the plastic remaining between the hose base outer peripheral surface and the hose inner peripheral surface). Agent) cannot be sufficiently absorbed and removed, and there is a tendency that the hose tends to come off or shift from the base due to vibration or the like. Conversely, if the content of the specific carbon black is too large, This is because there is a tendency to inhibit the flexibility.

<< Crosslinking agent (component D) >>
Examples of the crosslinking agent (component D) include sulfur vulcanizing agents such as sulfur and sulfur chloride, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3. , 5-trimethylcyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4'-di-t-butylperoxyvalerate, dicumyl peroxide, t-butylperoxybenzoate, Di-t-butylperoxy-diisopropylbenzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, di-t-butylperoxide, 2,5-dimethyl-2 , 5-Di-t-butylperoxyhexyne-3,1,3-bis- (t-butylperoxy-isopropyl ) Peroxide vulcanizing agent such as benzene and the like. These may be used alone or in combination of two or more. Of these, sulfur and dicumyl peroxide are preferably used.

  The content of the crosslinking agent (component D) is preferably 0.5 to 15 parts by weight, particularly preferably 1 to 10 parts by weight, and most preferably 2 to 7 parts by weight with respect to 100 parts by weight of EPDM (component A). It is. That is, if the content of the cross-linking agent (component D) is too small, the tensile strength tends to decrease, and if the content of the cross-linking agent (component D) is too large, the scorch resistance is deteriorated or stretched. This is because there is a tendency to decrease.

  The rubber composition for a hose of the present invention can be added with, for example, EPDM (A component), a specific plasticizer (B component), a specific carbon black (C component) and a cross-linking agent (D component) as necessary. Prepare by blending vulcanization accelerator, vulcanization aid, process oil, co-crosslinking agent, anti-aging agent, filler, etc., and kneading them using a kneader such as a kneader, Banbury mixer, roll, etc. Can do.

  And the hose of this invention can be produced as follows using the rubber composition for hoses prepared as mentioned above, for example. That is, first, the rubber composition for hoses prepared as described above is extruded into a tubular shape (cylindrical shape) to produce an unvulcanized hose. In addition, it is also possible to produce an unvulcanized hose by extruding a rubber composition on a straight mandrel during the extrusion. Thereafter, a desired hose can be obtained by vulcanization under predetermined conditions (140 to 160 ° C. × 30 to 60 minutes).

  If necessary, a reinforcing yarn layer, a rubber layer, a resin layer, or the like may be formed on the outer periphery of the hose having a single layer structure obtained as described above to form a hose having a multilayer structure.

  As described above, when the innermost layer of the hose is made of the rubber composition for a hose of the present invention, it is excellent in water resistance, heat resistance, sealability, etc., and an insertion aid is applied by a plasticizer that bleeds from the innermost layer. Even if it is not, the insertion load of the hose base can be reduced. As a result, the assembly work (insertion work) of the hose is facilitated, and furthermore, the operation cost can be suppressed because the application amount management of the insertion aid and the like becomes unnecessary. Moreover, since the plasticizer that has bleed on the inner peripheral surface of the hose is absorbed and removed after the assembly of the hose, problems such as hose disconnection after the assembly can be solved. Therefore, the above-mentioned hose improves the workability of assembling at locations where strong vibrations occur (locations where insertion aids could not be used due to concerns about hose removal after assembly), such as in the engine room. Can contribute greatly.

  And it is preferable to form a reinforcing yarn layer on the outer periphery of the innermost layer because the hose has excellent pressure resistance, durability and the like. The reinforcing yarn layer may be formed on the outer peripheral surface of the hose or may be formed between the layers.

  Examples of the reinforcing yarn for forming the reinforcing yarn layer include nylon reinforcing yarn, aromatic polyamide (aramid) fiber, polyester fiber such as polyethylene terephthalate (PET), and nylon (polyamide) fiber such as nylon 6 and nylon 66. And yarn made of polyvinyl alcohol (vinylon) fibers. These may be used alone or in combination of two or more. Especially, the reinforcement thread | yarn which consists of an aromatic polyamide fiber or a polyester fiber is used suitably at the point of the suppression effect of vibration transmission property, heat resistance, and pressure | voltage resistance.

  Examples of the method for braiding the reinforcing yarn include spiral winding, blade knitting, and knitting knitting.

  In the hose of the present invention, the thickness of the innermost layer (in the case of a single layer structure) is preferably 1 to 15 mm, particularly preferably 2 to 10 mm. The hose inner diameter is preferably 6 to 60 mm, particularly preferably 15 to 40 mm. That is, by setting within this range, it is possible to advantageously obtain the operational effects peculiar to the hose provided with the innermost layer made of the rubber composition for a hose of the present invention as described above.

  The hose of the present invention can be used for all hoses. For example, it can be used for water hoses such as radiator hoses, heater hoses and drain hoses, and air hoses such as turbo air hoses and vacuum brake hoses. And the said hose is used suitably for transport machines, such as a motor vehicle, a tractor, a cultivator, and a ship.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[EPDM]
Made by Sumitomo Chemical Co., Ltd., Esprene 532 (Diene content: 3.5% by weight)

〔stearic acid〕
Made by Nippon Oil & Fats Co., Ltd. Beads stearic acid sakura

[Zinc oxide]
2 types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

[Plasticizer (A1)]
Made by ADEKA, Adeka Sizer RS-107

[Plasticizer (A2)]
Idemitsu Oil Co., Diana Process PW-32

[Plasticizer (A3)]
Showa Ether, butyl benzyl phthalate

[Carbon black (B1)]
Cabot Corporation, Show Black IP200

[Carbon black (B2)]
SEAST S manufactured by Tokai Carbon Co., Ltd.

[Carbon black (B3)]
SEAST SO manufactured by Tokai Carbon

[Lubricant (C1)]
Made by Lion Akzo, Armoslip CP-P

[Lubricant (C2)]
Nippon Kasei Co., Ltd., Diamond L200

[Process oil]
Sunflex 2280, manufactured by Nippon Oil Corporation

[Vulcanization accelerator (i)]
Made by Sanshin Chemical Industry Co., Ltd., Sunseller TT-G

[Vulcanization accelerator (ii)]
Sunseller TET-G, manufactured by Sanshin Chemical Industry Co., Ltd.

[Vulcanization accelerator (iii)]
Sunseller CZ-G, manufactured by Sanshin Chemical Industry Co., Ltd.

[Vulcanization accelerator (iv)]
Nouchira BZ-G made by Ouchi Shinsei Chemical Co., Ltd.

[Vulcanizing agent (sulfur)]
Sulfax T-10, manufactured by Tsurumi Chemical Co., Ltd.

[Examples 1-7, Comparative Examples 1-8]
The above components were blended in the proportions shown in Tables 1 and 2 below, and kneaded using a Banbury mixer and an open roll to prepare a rubber composition. Specifically, the components excluding the vulcanizing agent and the vulcanization accelerator are kneaded for 5 minutes with a Banbury mixer and released when the temperature reaches 150 ° C. After obtaining a master batch, the vulcanization is performed on the master batch. A rubber composition was prepared by blending an agent and a vulcanization accelerator in the proportions shown in the same table and kneading them with an open roll.

  The rubber compositions of Examples and Comparative Examples thus obtained were extruded into a tubular (cylindrical) shape having an inner diameter of 30 mm and a wall thickness of 4 mm, then cut to a length of 300 mm, and a straight metal having an outer diameter of 30 mm. A mandrel was interpolated. And after performing steam vulcanization | cure for 20 minutes at 160 degreeC, it extracted from the metal mandrel and obtained the rubber hose. With respect to this rubber hose, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 and 2 below.

[Insertability]
A metal pipe having an outer diameter of 17 mm is manually inserted into the end opening of each rubber hose obtained as described above, and the maximum value of the load (insertion load) on the hose side at that time is determined by an autograph (manufactured by TOYOSEIKI). , STORAGRAPH). And the thing whose value is less than 90N was evaluated as "(circle)", the thing which is 90N or more and less than 150N was evaluated as "(triangle | delta)", and the thing which is 150N or more was evaluated as "*". As shown in Table 1 below, only in Comparative Example 2, the insertion aid (lubricating oil) was applied to the inner surface of the hose, and the above insertion was performed.

[Sealability]
Each rubber hose obtained as described above was sealed with antifreeze solution (LLC) conforming to JIS K 2234 diluted to 50% with water, pressurized at 0.05 MPa in a 120 ° C. atmosphere, and held for 30 seconds. If not, 0.05 MPa pressurization (held for 30 seconds) was repeated, and the leaked pressure was measured. And the thing whose value is 0.50 MPa or more is evaluated as “◯”, the one that is 0.35 MPa or more and less than 0.50 MPa is evaluated as “Δ”, and the one that is less than 0.35 MPa is “×”. It was evaluated. As shown in Table 1 below, only in Comparative Example 1, the insertion aid (lubricating oil) was applied to the inner surface of the hose, and the above insertion was performed.

[Compression set]
With respect to the rubber constituting each rubber hose, a low temperature compression set test after 48 hours in an atmosphere of −25 ° C. was evaluated according to JIS K 6262. And the thing whose value is less than 80% was evaluated as "(circle)", and the thing which is 80% or more was evaluated as "x".

  From the results in the above table, all of the rubber hoses of the examples are excellent in the insertability of the metal pipe without application of an insertion aid, and excellent results are also obtained in the sealing performance and compression set evaluation. It was.

  On the other hand, Comparative Example 1 did not contain a plasticizer, and the insertion aid was not applied in the same manner as in the example, so that the metal pipe was poorly inserted. In Comparative Example 2, since the insertion aid was applied, the insertion performance of the metal pipe was excellent, but the sealing performance after insertion was deteriorated. In Comparative Example 3, since the SP value of the plasticizer was too small, the metal pipe was poorly inserted. In Comparative Example 4, since the DBP oil absorption of carbon black was too small, the sealing performance deteriorated as to whether the plasticizer was insufficiently absorbed and removed. In Comparative Examples 5 and 6, due to the action of the lubricant in the rubber hose, the insertion performance of the metal pipe was excellent, but the compression set was inferior to the Examples. In Comparative Example 7, since the content of the specific plasticizer was too small, intentional bleeding of the plasticizer was difficult to occur, resulting in poor metal pipe insertability. In Comparative Example 8, since the content of the specific plasticizer was too large, the sealing performance was inferior due to excessive bleeding.

  The rubber composition for a hose of the present invention is a fuel for transporting low-concentration fuel such as a water hose such as a radiator hose, a heater hose, a drain hose, an air hose such as a turbo air hose and a vacuum brake hose, and a vapor hose. Can be used for hoses. And the said hose can be used for transport machines, such as a motor vehicle, a tractor, a cultivator, and a ship.

Claims (4)

A rubber composition for hose containing the following (A) as a rubber component and the following (B) to (D) components, the content of the (B) component with respect to 100 parts by weight of the (A) component: Is a rubber composition for a hose, characterized by being 0.5 to 10 parts by weight.
(A) Ethylene-propylene-diene terpolymer rubber (EPDM).
(B) A plasticizer having an SP value of 9.2 or more.
(C) Carbon black having a DBP oil absorption of 100 ml / 100 g or more.
(D) Crosslinking agent.   The rubber composition for a hose according to claim 1, wherein the content of the component (C) is 50 to 190 parts by weight with respect to 100 parts by weight of the component (A).   A hose characterized in that the innermost layer of the hose comprises the rubber composition for a hose according to claim 1 or 2.   The hose according to claim 3, wherein a reinforcing yarn layer is formed on the outer periphery of the innermost layer.