JP2007090563A - Low permeation hose and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low permeation hose which is excellent in interlayer adhesion properties and low permeability to fuel, a cooling medium, etc. <P>SOLUTION: In the low permeation hose, a tubular inner layer 1 is formed by using an inner layer material containing a polyarylene sulfide resin or a polyamide 9T resin as a main component, and the peripheral surface of the inner layer 1 is plasma-treated. On the plasma-treated surface, an outer layer 2 formed by using a rubber composition containing an ethylene-propylene-diene terpolymer and/or an ethylene-propylene copolymer (A), a peroxide vulcanizing agent (B), a resorcinol compound (C), or a melamine resin (D) as a indispensable component is formed directly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a low-permeability hose and a method for producing the same, and more specifically, gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG used in automobiles and the like. The present invention relates to a low-permeability hose excellent in permeation resistance to refrigerants such as (liquefied petroleum gas) or refrigerants such as chlorofluorocarbons, alternative chlorofluorocarbons, water, and carbon dioxide used in air conditioners and radiators, and a method for producing the same.

  Due to the increasing global environmental awareness, regulations on the evaporation of hydrocarbons from fuel hoses for automobiles and the like have been strengthened, and in particular, strict transpiration regulations have been legislated in the United States. Under such circumstances, a hose having a multilayer structure having a low fuel permeation layer made of a fluororesin has been proposed in order to comply with the regulation of the amount of hydrocarbon transpiration.

  The multi-layer hose using the fluororesin has relatively low fuel permeation performance, but when more severe fuel low permeation performance is required, the thickness of the fluororesin layer must be increased, Therefore, there is a drawback that the hose becomes expensive.

  Thus, polyarylene sulfide resins, particularly polyphenylene sulfide (PPS) resins, are attracting attention as resins that have better fuel permeation performance than fluororesins. Since this PPS resin is excellent in low fuel permeation performance, sufficient fuel low permeation performance can be obtained even if it is relatively thin. Therefore, compared with the hose which forms a fuel low-permeability layer using a fluorine-type resin, it is excellent in low permeability and is advantageous also in price.

Thus, as a hose provided with a low fuel permeation layer made of PPS resin, for example, an outer layer made of a thermoplastic resin (polyamide resin or the like) other than PPS resin on the outer periphery of the inner layer (low fuel permeation layer) made of PPS resin. Has been proposed (see Patent Document 1).
JP 10-138372 A

  Since the multilayer fuel tube described in Patent Document 1 has poor interlayer adhesion between an inner layer made of PPS resin and an outer layer made of polyamide resin or the like, a large amount of polyamide resin is compounded with PPS resin which is an inner layer material. It is necessary to use However, since the polyamide resin is a fuel-impermeable resin, if it is blended in a large amount, the blending ratio of the PPS resin decreases, and the low fuel permeability of the inner layer decreases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-permeability hose that is excellent in interlayer adhesion and excellent in low-permeability with respect to fuel, refrigerant, and the like, and a method for producing the same.

In order to achieve the above object, the present invention provides a tubular inner layer formed of an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and the outer peripheral surface of the inner layer is subjected to plasma treatment. The first gist is a low-permeability hose in which an outer layer made of a rubber composition containing the following components (A) to (D) as essential components is directly formed on the plasma-treated surface.
(A) At least one of an ethylene-propylene-diene terpolymer and an ethylene-propylene copolymer.
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.

Further, in the present invention, an inner layer is formed using an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and then the outer peripheral surface of the inner layer is subjected to plasma treatment. The manufacturing method of the low-permeability hose which directly forms an outer layer using the rubber composition which has the following (A)-(D) as an essential component is made into the 2nd summary.
(A) At least one of an ethylene-propylene-diene terpolymer and an ethylene-propylene copolymer.
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.

  The inventors of the present invention have made extensive studies in order to obtain a low-permeability hose that is excellent in interlayer adhesion and excellent in low-permeability with respect to fuel, refrigerant, and the like. As a result, a tubular inner layer is formed using an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and the outer peripheral surface of the inner layer is plasma-treated, and on the plasma-treated surface. The inventors have found that the intended purpose can be achieved by a low-permeability hose in which an outer layer made of a rubber composition containing the above (A) to (D) as essential components is directly formed, and the present invention has been achieved. That is, the low permeation performance with respect to a fuel, a refrigerant | coolant, etc. can be acquired by the barrier effect of the polyarylene sulfide resin or the polyamide 9T resin which is a material for inner layers. And when the outer peripheral surface of an inner layer is plasma-processed, the interlayer adhesiveness with the outer layer which uses the rubber composition which has said (A)-(D) as an essential component will improve. The reason for this is not clear, but is presumed as follows. That is, it is presumed that the outer peripheral surface of the inner layer is roughened by the plasma treatment, and the interlayer adhesion between the inner layer and the outer layer is improved by a so-called anchoring effect (anchor effect). In addition, the sulfur treatment of the polyarylene sulfide resin in the inner layer material is activated by the plasma treatment, or the terminal amino group or polyamide bond (—CONH—) portion of the polyamide 9T resin in the inner layer material is activated, It is presumed that the activated part may be bonded to the resorcinol compound in the outer layer material to improve the adhesion. In addition, when corona discharge treatment is performed instead of plasma treatment, excessive charges may be locally applied, the inner layer may deteriorate, and in the worst case, a hole may be formed on the inner layer surface.

  As described above, the low-permeability hose of the present invention can obtain excellent low-permeability performance for fuel, refrigerant, and the like due to the barrier effect of the polyarylene sulfide resin or polyamide 9T resin that is the inner layer material. Further, when the outer peripheral surface of the inner layer is activated and roughened by plasma treatment, the interlayer adhesion between the inner layer and the outer layer is improved. The reason why the interlaminar adhesion is improved by this plasma treatment is that, as described above, in addition to the anchoring effect (anchor effect), the activated portion in the inner layer material is bonded to the resorcinol compound in the outer layer material, resulting in adhesion. It is assumed that it is due to improvement. The outer layer of the low-permeability hose of the present invention has been conventionally used as an outer layer material because it has at least one rubber of an ethylene-propylene-diene terpolymer and an ethylene-propylene copolymer as a main component. Compared with polyamide 12 (PA12), the cost can be reduced. In addition, when used on the engine room side, a rubber tube may be attached to the outer periphery of the resin hose as a protector, but the low-permeability hose of the present invention has an outer layer formed of a special rubber composition. Even when used on the room side, there is no need to attach a rubber tube as a protector.

  And the low-permeability hose of this invention carries out the plasma processing of the outer peripheral surface of the inner layer formed using the material for inner layers, Then, on this plasma processing surface, said (A)-(D) is made into an essential component. It can manufacture by forming an outer layer directly using the rubber composition to do. As a result, a low-permeability hose having good interlayer adhesion between the inner layer and the outer layer can be easily produced without using an adhesive, and the production efficiency is improved.

  Next, embodiments of the present invention will be described in detail.

  For example, as shown in FIG. 1, the low-permeability hose of the present invention is configured by directly forming an outer layer 2 on a plasma-treated surface of a tubular inner layer 1.

In the present invention, the inner layer 1 is formed of a tubular inner layer using an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and the outer peripheral surface of the inner layer is subjected to plasma treatment, and The outer layer made of a rubber composition containing the following components (A) to (D) as essential components is directly formed on the plasma-treated surface, and these are the greatest features. According to the present invention, as described above, the inner layer and the outer layer can be satisfactorily bonded without using an adhesive, and the low permeation performance with respect to fuel, refrigerant and the like is improved.
(A) At least one of ethylene-propylene-diene terpolymer and ethylene-propylene copolymer (ethylene-propylene-diene terpolymer and / or ethylene-propylene copolymer).
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.

  In the present invention, the main component means a component that generally occupies a majority of the whole, and includes the case where the whole consists only of the main component.

  As the material (inner layer material) used for forming the inner layer 1, polyarylene sulfide resin or polyamide 9T (PA9T) resin is used, and the polyarylene sulfide resin is excellent in low permeation performance with respect to fuel, refrigerant and the like. preferable.

  Examples of the polyarylene sulfide (PAS) resin include a repeating unit represented by the structural formula [—Ar—S—] [wherein Ar is an arylene group (divalent aromatic hydrocarbon group) and S is sulfur]. Is a polymer containing 70 mol% or more of the total. That is, when the proportion of the repeating unit represented by the above structural formula is less than 70 mol% of the whole, there are few original crystal components that are characteristic of the crystalline polymer, and the mechanical strength may be insufficient. It is.

  And as a specific example of the said PAS resin, what contains 70 mol% or more of the whole repeating unit represented by following General formula (1) is mention | raise | lifted.

  In the general formula (1), R is substituted with an alkyl group having 6 or less carbon atoms or an alkoxyl group, a phenyl group, a carboxyl group or a metal base thereof, an amino group, a nitro group, or a halogen such as fluorine, chlorine or bromine. Represents a substituent. Moreover, m shows the integer of 0-4. The average degree of polymerization (n) is usually n = 10 to 300.

  Further, the PAS resin may be a homopolymer of the repeating unit represented by the general formula (1), but the co-polymerization with the structural unit other than the repeating unit represented by the general formula (1). They can be combined. Examples of such structural units include m-phenylene sulfide units, o-phenylene sulfide units, p, p'-diphenylene ketone sulfide units, p, p'-diphenylene sulfone sulfide units, p, p'-biphenylenes. Examples thereof include a sulfide unit, p, p′-diphenylenemethylene sulfide unit, p, p′-diphenylenecumenyl sulfide unit, and naphthyl sulfide unit. The molecular structure of the polymer having the structural unit may be any of a linear structure, a branched structure, or a crosslinked structure, and a polymer having these structural units may be blended and used.

  In addition, the PAS resin may be one having improved moldability by increasing the melt viscosity by oxidative crosslinking or thermal crosslinking of the polymer having the structural unit.

  Among the PAS resins, a polyphenylene sulfide (PPS) resin is preferable from the viewpoint of cost and the like. As the PPS resin, for example, those having a repeating unit represented by the following general formula (2) are preferable. The PPS resin may have a functional group in the molecular structure (including molecular ends). Examples of the functional group include an epoxy group, a hydroxyl group, a carboxylic acid anhydride residue, a carboxylic acid group, an acrylate group, a carbonate group, and an amino group.

The melt viscosity of the PPS resin is not particularly limited as long as it can be melt kneaded, but is preferably in the range of 5 to 2000 Pa · s (320 ° C., shear rate 1000 sec ⁻¹ ), particularly preferably 10 to 500 Pa · s. Is within the range.

  The PA9T resin is composed of a dicarboxylic acid unit (Ia) mainly composed of terephthalic acid and a diamine unit (Ib) mainly composed of 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit. It is mainly composed. This PA9T resin has excellent properties such as low permeability, heat resistance, and low water absorption compared to polyamide 6 (PA6) resin and the like.

  The dicarboxylic acid unit (Ia) constituting the PA9T resin has a terephthalic acid component of 60 mol% or more, preferably 75 mol% or more, more preferably 90 mol% or more. That is, when the terephthalic acid component is less than 60 mol%, the heat resistance is lowered, which is not preferable.

  The dicarboxylic acid component other than the terephthalic acid component that can be contained in the PA9T resin includes malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2, Aliphatic dicarboxylic acids such as 2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; alicyclics such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid Dicarboxylic acid; isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, Diphenic acid, dibenzoic acid, 4,4-oxydibenzoic acid, diphenylmethane-4,4-dicarbo Acid, diphenylsulfone-4,4-dicarboxylic acid, aromatic dicarboxylic acids such as 4,4-biphenyl dicarboxylic acid, or can be given any mixture thereof. Of these, aromatic dicarboxylic acids are preferably used. Furthermore, polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid can be used within a range where melt molding is possible.

  The diamine unit (Ib) constituting the PA9T resin is such that the 1,9-nonanediamine unit and the 2-methyl-1,8-octanediamine unit are 60 mol% or more, preferably 75 mol% or more, more preferably. Is 90 mol% or more. That is, if the above 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit are less than 60 mol%, characteristics such as heat resistance, moldability, low water absorption, and lightness become insufficient. It is not preferable.

  The molar ratio of 1,9-nonanediamine unit to 2-methyl-1,8-octanediamine unit is 100: 0 to 20:80, preferably 100: 0 to 60:40, and more preferably 100: 0. ~ 80: 20. That is, when the molar ratio of the 1,9-nonanediamine unit to the 2-methyl-1,8-octanediamine unit is out of the range of 100: 0 to 20:80, the heat resistance becomes insufficient, which is not preferable. .

  Examples of diamine components other than the 1,9-nonanediamine and 2-methyl-1,8-octanediamine component include ethylenediamine, propylenediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,8- Octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 3-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl Aliphatic diamines such as 1,6-hexanediamine and 5-methyl-1,9-nonanediamine; Alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine and isophoronediamine; p-phenylenediamine, m-phenylenediamine and xylene Diamine, 4,4-diaminodiphenylmethane, 4,4-di Mino diphenyl sulfone, 4,4-aromatic diamines diaminodiphenyl ether, etc., or can be given any mixture thereof.

  The PA9T resin can be produced using any method known as a method for producing crystalline polyamide. For example, it can be polymerized by a solution polymerization method or an interfacial polymerization method using acid chloride and diamine as raw materials, a melt polymerization method using dicarboxylic acid and diamine as raw materials, a solid phase polymerization method, a melt extruder polymerization method or the like.

  The PA9T resin can be produced, for example, by the following polymerization method. That is, diamine and dicarboxylic acid were added all at once to produce a nylon salt, and then the intrinsic viscosity [η] at 30 ° C. in concentrated sulfuric acid at a temperature of 200 to 250 ° C. was 0.10 to 0.60 dl / g. A PA9T resin can be easily obtained by solid-phase polymerization or polymerization using a melt extruder.

  When the intrinsic viscosity [η] of the prepolymer is in the range of 0.10 to 0.60 dl / g, there is little shift in the molar balance of the carboxyl group and amino group and a decrease in the polymerization rate in the post-polymerization stage. A PA9T resin having a small molecular weight distribution and excellent performance and moldability can be obtained. When the final stage of the polymerization is carried out by solid phase polymerization, it is preferably carried out under reduced pressure or under an inert gas flow. If the polymerization temperature is in the range of 200 to 280 ° C., the polymerization rate is high and productivity is improved. It is preferable because it is excellent and can effectively suppress coloring and gelation. When the final stage of the polymerization is carried out by a melt extruder, it is preferable that the polymerization temperature is 370 ° C. or lower because there is almost no degradation of the polyamide and a PA9T resin having no deterioration can be obtained.

  In producing the PA9T resin, for example, as a catalyst, phosphoric acid, phosphorous acid, hypophosphorous acid or a salt or ester thereof, specifically potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese Add metal salt such as tin, tungsten, germanium, titanium, antimony, ammonium salt, ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester, decyl ester, stearyl ester, phenyl ester, etc. Can do.

  The PA9T resin preferably has an intrinsic viscosity [η] measured at 30 ° C. in concentrated sulfuric acid from 0.6 to 2.0 dl / g in view of mechanical properties, moldability, and the like. It is more preferably 0.7 to 1.9 dl / g, and still more preferably 0.8 to 1.8 dl / g.

  In the present invention, when a PAS resin is used as the inner layer material, a thermoplastic elastomer may be blended in order to improve flexibility and impact resistance. The thermoplastic elastomer is preferably meltable, mixed and dispersible at the temperature at which the PAS resin is kneaded. From this point, an elastomer having a melting point of 300 ° C. or less and having rubber elasticity at room temperature is preferable. Among the above-mentioned thermoplastic elastomers, those having a glass transition point of −40 ° C. or lower are preferable in view of improving heat resistance, ease of mixing, and low-temperature impact resistance, because they have rubber elasticity even at low temperatures. The glass transition point is preferably as low as possible, but is usually preferably in the range of -180 to -40 ° C, particularly preferably in the range of -150 to -40 ° C.

  The thermoplastic elastomer is a thermoplastic having at least one functional group selected from the group consisting of epoxy groups, amino groups, hydroxyl groups, carboxyl groups, mercapto groups, isocyanate groups, vinyl groups, acid anhydride groups, and ester groups. An elastomer is preferable from the viewpoint of improving low-temperature impact resistance, and among these, a functional group derived from a carboxylic acid such as an epoxy group or an acid anhydride, an acid, or an ester has a high affinity with a PAS resin. This is particularly preferable.

  The thermoplastic elastomer can be obtained, for example, by copolymerization of α-olefins and vinyl polymerizable compounds having the functional group. Examples of the α-olefins include α-olefins having 2 to 8 carbon atoms such as ethylene, propylene, and butene-1. Examples of the vinyl polymerizable compounds having the above functional group include α, β-unsaturated carboxylic acids such as (meth) acrylic acid and (meth) acrylic acid esters and alkyl esters thereof, maleic acid, fumaric acid, and itacon. Examples include acids, other unsaturated dicarboxylic acids having 4 to 10 carbon atoms, mono- and diesters thereof, α, β-unsaturated dicarboxylic acids such as acid anhydrides and derivatives thereof, glycidyl (meth) acrylate, and the like.

  Among these, the molecule has at least one functional group selected from the group consisting of an epoxy group, amino group, hydroxyl group, carboxyl group, mercapto group, isocyanate group, vinyl group, acid anhydride group, and ester group. An ethylene-propylene copolymer or an ethylene-butene copolymer is preferably used, and an ethylene-propylene copolymer or an ethylene-butene copolymer having a carboxyl group is more preferable.

  The mixing ratio of the PAS resin and the thermoplastic elastomer during the mixing is preferably 1 to 50 parts of the thermoplastic elastomer with respect to 99 to 50 parts by weight of the PAS resin (hereinafter abbreviated as “part”). It is especially preferable that it is 5-50 parts of thermoplastic elastomers with respect to 99-50 parts. When the blending amount of the thermoplastic elastomer is within the above range, the fuel barrier property and the low temperature collision resistance are further improved.

  In addition, the inner layer material used in the present invention may appropriately contain an organic compound having a functional group, an impact resistance improver, an antiaging agent, a flame retardant, and the like together with the PAS resin or PA9T resin.

  The organic compound having the functional group is not particularly limited, and examples thereof include ethylene-glycidyl methacrylate (EGMA), modified EGMA, ethylene-glycidyl methacrylate-vinyl acetate terpolymer, ethylene-glycidyl methacrylate-methyl acrylate terpolymer. Copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl acrylate-acrylic acid terpolymer, ethylene-ethyl acrylate copolymer (EEA), modified EEA, modified ethylene-ethyl acrylate-maleic anhydride copolymer Polymer, ethylene-methacrylate copolymer, acrylic rubber, ethylene-vinyl acetate copolymer (EVA), modified EVA, modified polypropylene (PP), modified polyethylene (PE), ethylene-acrylic acid ester-maleic anhydride ternary Mutual weight Epoxidized styrene-butadiene-styrene block copolymer (SBS), epoxidized styrene-ethylene-butadiene-styrene block copolymer (SEBS), acid-modified SBS, acid-modified SEBS, styrene-isopropenyl oxazoline copolymer , Thermoplastic urethane, thermoplastic elastomer, polyamide resin, polyester resin, ε-caprolactam, ω-aminoundecanoic acid, ω-aminododecanoic acid, ω-laurolactam and the like. These may be used alone or in combination of two or more.

  Examples of the modified EGMA include those obtained by grafting polystyrene (PS), polymethyl methacrylate (PMMA), acrylonitrile-styrene copolymer (AS), a copolymer of PMMA and butyl acrylate, etc. to EGMA. It is done.

  Examples of the modified EEA include EEA grafted with a copolymer of PS, PMMA, AS, PMMA and butyl acrylate, maleic anhydride-modified EEA, silane-modified EEA, and the like.

  As the modified ethylene-ethyl acrylate-maleic anhydride copolymer, for example, a copolymer of PS, PMMA, AS, PMMA and butyl acrylate is grafted to the ethylene-ethyl acrylate-maleic anhydride copolymer. And so on.

  Examples of the modified EVA include EVA grafted with a copolymer of PS, PMMA, AS, PMMA and butyl acrylate, and the like.

  Moreover, as modified PP, what grafted PS or AS to PP, maleic anhydride modified PP, etc. are mention | raise | lifted, for example.

  In addition, as the modified PE, for example, any one of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), PS, PMMA, AS, PMMA and butyl acrylate Examples include grafted copolymers and maleic anhydride-modified PE.

  The impact resistance improver is not particularly limited. For example, ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene copolymer (EPM), hydrogenated acrylonitrile-butadiene copolymer (H- NBR) and the like, and thermoplastic elastomers and resins such as EGMA, modified EGMA, SBS, acid-modified SBS, SEBS, epoxidized SEBS, acid-modified SEBS, and polybutene. These may be used alone or in combination of two or more.

  Further, the blending ratio of the impact resistance improving material is preferably in the range of 1 to 80 parts, particularly preferably in the range of 2 to 70 parts, with respect to 100 parts of the PAS resin or polyamide 9T resin as the material for the inner layer. It is.

  In the present invention, a compound material layer (adhesive layer) of PAS resin and polyamide resin may be provided on the inner peripheral surface side of the inner layer 1, and the innermost layer may be formed on the inner side. The innermost layer material is not particularly limited, and examples thereof include a modified fluororesin. In addition, the modified fluororesin may be subjected to a conductive treatment with a conductive agent such as carbon black, for example.

Next, as the rubber composition (outer layer material) used for forming the outer layer 2, those having the following (A) to (D) as essential components are used.
(A) At least one of ethylene-propylene-diene terpolymer (EPDM) and ethylene-propylene copolymer (EPM).
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.

  As the EPDM, for example, those having an iodine value in the range of 6 to 30 and an ethylene ratio in the range of 48 to 70% by weight are preferable, and particularly preferably, the iodine value is in the range of 10 to 24 and the ethylene ratio is 50 to 60% by weight. %.

  The diene monomer (third component) contained in the EPDM is not particularly limited, but 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.

  Examples of the peroxide vulcanizing agent (component B) used together with the specific rubber (component A) include 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-butyl peroxide, 2,5-dimethyl- 2,5-di-t-butylperoxyhexyne-3 and the like. These may be used alone or in combination of two or more. Among these, di-t-butylperoxy-diisopropylbenzene is preferably used in that there is no problem with odor.

  The mixing ratio of the peroxide vulcanizing agent (component B) is preferably in the range of 1.5 to 20 parts with respect to 100 parts of the specific rubber (component A). That is, when the B component is less than 1.5 parts, crosslinking is insufficient and the hose strength is inferior, and conversely, when the B component exceeds 20 parts, it becomes too hard and the hose is less flexible. Because it is.

  The resorcinol compound (C component) used together with the A component and the B component is not particularly limited as long as it mainly acts as an adhesive. For example, modified resorcin / formaldehyde resin, resorcin, resorcin / formaldehyde (RF ) Resins and the like. These may be used alone or in combination of two or more. Among these, modified resorcin / formaldehyde resin is preferably used in terms of transpiration, hygroscopicity, and compatibility with rubber.

  Examples of the modified resorcin / formaldehyde resin include those represented by the following general formulas (3) to (5). Among these, those represented by the following general formula (3) are particularly preferable.

  The blending ratio of the resorcinol compound (component C) is preferably in the range of 0.1 to 10 parts, particularly preferably 0.5 to 5 parts, with respect to 100 parts of the specific rubber (component A). That is, if the C component is less than 0.1 part, the adhesiveness with the inner layer 1 tends to deteriorate, and conversely if the C component exceeds 10 parts, the cost increases.

  The melamine resin (D component) used together with the components A to C is not particularly limited as long as it mainly acts as an adhesion aid. For example, methylated formaldehyde / melamine polymer, hexamethylenetetramine, etc. can give. These may be used alone or in combination of two or more. Among these, methylated formaldehyde / melamine polymers are preferably used in terms of transpiration, hygroscopicity, and compatibility with rubber.

  As the methylated product of the formaldehyde / melamine polymer, for example, those represented by the following general formula (6) are preferably used.

  Among the melamine resins (component D), a mixture of the compounds represented by the general formula (6) is preferable. The compound with n = 1 is 43 to 44% by weight, and the compound with n = 2 is 27 to 30. Particularly preferred is a mixture of 26-30% by weight of the compound of wt%, n = 3.

  Further, the blending ratio of the resorcinol compound (C component) and the melamine resin (D component) is preferably in the range of C component / D component = 1 / 0.5 to 1/2, particularly preferably. Is C component / D component = 1 / 0.77 to 1 / 1.5. That is, when the weight ratio of the D component is less than 0.5, the tensile strength (TB) and the elongation (EB) of the outer layer 2 tend to be slightly deteriorated. If it exceeds the upper limit, the adhesiveness is saturated and the adhesive force is stabilized. Therefore, even if the weight ratio of the D component is further increased, only the cost is increased, and no further effect can be expected.

  In addition to the above components A to D, the outer layer material requires carbon black, process oil, anti-aging agent, processing aid, crosslinking accelerator, white filler, reactive monomer, foaming agent, etc. Depending on the case, it may be appropriately blended.

  The outer layer material can be prepared by blending the components A to D and other components as necessary, and kneading them using a kneader such as a roll, a kneader, or a Banbury mixer.

  Here, the low-permeability hose of the present invention as shown in FIG. 1 can be produced, for example, as follows. That is, an inner layer material and an outer layer material are prepared. Next, the inner layer material is extruded into a hose shape to form a tubular inner layer 1. At this time, a mandrel may be used. Next, the outer peripheral surface of the inner layer 1 is subjected to plasma treatment under a predetermined condition using a high frequency plasma apparatus. Next, the outer layer material is extruded into a hose shape on the plasma-treated surface. Thereafter, vulcanization is performed under predetermined conditions (preferably 160 to 185 ° C. × 60 to 15 minutes), and the outer peripheral surface of the inner layer 1 is subjected to plasma processing, and the outer layer 2 is directly formed on the plasma processing surface. A low-permeability hose having a two-layer structure can be produced.

The plasma treatment conditions are as follows: reaction pressure is 1 to 300 Pa, gas types are Ar, N ₂ , O ₂ , He, Ne, H ₂ , output is 0 to 6 kW, treatment time is 1 second to 20 minutes, oscillation The output is preferably 13.56 MHz (due to legal restrictions) ± 0.05% (due to manufacturer specifications).

  In the low-permeability hose of the present invention, the hose inner diameter is preferably in the range of 2 to 40 mm, particularly preferably in the range of 2.5 to 36 mm, and the hose outer diameter is preferably in the range of 3 to 44 mm, particularly preferably. It is in the range of 4 to 40 mm. The thickness of the inner layer 1 is preferably in the range of 0.02 to 1.0 mm, particularly preferably in the range of 0.05 to 1.0 mm. Moreover, the thickness of the outer layer 2 is usually in the range of 0.2 to 1.5 mm, and preferably in the range of 0.3 to 1.0 mm.

  Note that the low-permeability hose of the present invention is not limited to the two-layer structure as shown in FIG. 1. For example, as described above, the innermost layer is formed on the inner peripheral surface side of the inner layer 1. In addition, other layers may be formed on the outer peripheral surface side of the outer layer 2.

  The low-permeability hose of the present invention is used in automobiles and transportation equipment (industrial transport vehicles such as airplanes, forklifts, excavators, cranes, railway vehicles, etc.) and the like, gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, Fuel transportation hoses such as light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied petroleum gas), or refrigerant transportation hoses used for air conditioners and radiators, etc. Is preferably used.

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

  First, the rubber composition shown below was prepared as a material for the outer layer of the low-permeability hose.

[Preparation of rubber compositions A to G, a to c]
The components shown in Table 1 and Table 2 below were blended in the proportions shown in the same table and kneaded using a roll to prepare a rubber composition.

  Next, the fuel hose was produced using the said material.

[Example 1]
On a mandrel made of TPX (methyl pentene resin) having an outer diameter of 6 mm, a PPS resin (Torelina A670X01, manufactured by Toray Industries, Inc.) was extruded into a hose shape to form a tubular inner layer (thickness 0.1 mm). Next, plasma treatment was performed on the outer peripheral surface of the inner layer under the conditions of reaction pressure: 67 Pa, gas type: Ar, output: 200 W, processing time: 20 seconds, oscillation output: 13.56 MHz, using an in-house high-frequency plasma apparatus. Went. Next, the rubber composition A (outer layer material) was extruded into a hose shape on the plasma-treated surface. Thereafter, a 165 ° C. × 45 minute vulcanization is performed, and a two-layer fuel hose (inner diameter: 6 mm, outer diameter: 12 mm) is formed by plasma processing on the outer peripheral surface of the inner layer and forming the outer layer directly on the plasma processing surface. Produced.

[Examples 2 to 14]
A fuel hose (inner diameter: 6 mm, outer diameter: 12 mm) was prepared in the same manner as in Example 1 except that the type of inner layer material or outer layer material (rubber composition) was changed to those shown in Tables 3 and 4 below. Produced.

[Comparative Examples 1-8]
As shown in Table 5 below, the fuel hose (inner diameter: 24 mm) was changed according to Example 1 except that the type of the inner layer material or outer layer material (rubber composition) was changed and plasma treatment was not performed. Produced. That is, PPS resin or PA9T resin was extruded into a hose shape on a TPX mandrel having an outer diameter of 6 mm to form a tubular inner layer (thickness 0.1 mm). Next, a rubber composition (outer layer material) was extruded into a hose shape on the surface of the inner layer. Thereafter, vulcanization was carried out at 165 ° C. for 45 minutes to prepare a two-layer fuel hose (inner diameter 6 mm, outer diameter 12 mm) in which the outer layer was directly formed on the outer peripheral surface of the inner layer.

  Using the fuel hoses of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 3 to 5 below.

[Gasoline permeation]
The outer diameter of both ends of a 10-m long fuel hose (inner diameter 6 mm) was expanded using a conical jig so that the inner diameter of the end of the fuel hose was 10 mm, and the outer periphery of the end was rounded. Two 8 mm metal pipes (but two bulge processing parts expanded to an outer diameter of 10 mm) were prepared, and one pipe was press-fitted into the end of the fuel hose. Then, one metal pipe was fitted with a screw type blind plug, and the other metal pipe was fitted with a metal valve. Next, indole gasoline containing 10% by volume of ethanol is sealed in the fuel hose from the side of the metal pipe equipped with the above-described metal valve, and treated at 40 ° C. for 3000 hours (in addition, 10% by volume of ethanol every week). The contained indolen gasoline was replaced). Then, the gasoline permeation amount was measured for 3 days by the CARB SHED method DBL pattern, and the gasoline permeation amount per 1 m of the fuel hose was calculated on the day when the gasoline permeation amount was the maximum. In the above measurement method, since 0.1 mg / m / day is the measurement limit, the value that was less than 0.1 mg / m / day was described as “<0.1”.

(Interlayer adhesion)
Each fuel hose was divided into two in the longitudinal direction to prepare a sample. The inner layer / outer layer of each sample was peeled and sandwiched between chucks of a tensile tester, and the 180 ° peel strength (N / cm) was measured under the condition of a tensile speed of 50 mm / min. Moreover, the peeling interface was described in the table | surface. If the peel strength is 20 N / cm or more, it is considered that the interlayer adhesion is good.

  From the above results, the products of all examples were excellent in gasoline low permeability and in interlayer adhesion. In particular, the products of Examples 1 to 7 in which the inner layer was formed using the PPS resin were further superior in gasoline low permeability than the products of Examples 8 to 14 in which the inner layer was formed using the PA9T resin.

  On the other hand, since all the comparative example products did not perform plasma treatment on the outer peripheral surface of the inner layer, the interlayer adhesion between the inner layer and the outer layer was inferior.

  The low-permeability hose of the present invention is used in automobiles and the like, and transports fuel such as gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), and LPG (liquefied petroleum gas). Can be suitably used for refrigerant hoses for refrigerants such as chlorofluorocarbons, alternative chlorofluorocarbons, water, carbon dioxide, etc. used for air conditioners and radiators.

It is a schematic diagram which shows an example of the low-permeability hose of this invention.

Explanation of symbols

1 Inner layer 2 Outer layer

Claims (3)

A tubular inner layer is formed using an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and the outer peripheral surface of the inner layer is plasma-treated. On the plasma-treated surface, the following A low-permeability hose characterized in that an outer layer made of a rubber composition containing (A) to (D) as essential components is directly formed.
(A) At least one of an ethylene-propylene-diene terpolymer and an ethylene-propylene copolymer.
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.   The low-permeability hose according to claim 1, which is a hose for automobile fuel transportation or a hose for refrigerant transportation. An inner layer is formed using an inner layer material mainly composed of polyarylene sulfide resin or polyamide 9T resin, and then the outer peripheral surface of the inner layer is subjected to plasma treatment, and then the following (A) to (A) to A method for producing a low-permeability hose, wherein the outer layer is directly formed using a rubber composition containing (D) as an essential component.
(A) At least one of an ethylene-propylene-diene terpolymer and an ethylene-propylene copolymer.
(B) Peroxide vulcanizing agent.
(C) Resorcinol compound.
(D) Melamine resin.

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