JP5506178B2 - Refrigerant transport hose - Google Patents

Description

  The present invention relates to a refrigerant transport hose, and more particularly, to a refrigerant transport hose having a gas barrier layer made of a polyamide resin composition.

  Conventionally, CFCs such as HFC-134a (R-134a) have been used as refrigerants in automobile air conditioners.

  From the viewpoint of improving ride comfort, a rubber hose having excellent vibration absorption performance is used for the piping of this automobile air conditioner.

  The rubber hose has a structure in which a nylon resin layer with excellent gas barrier properties and excellent vibration durability such as impulse resistance is disposed on the innermost layer to prevent refrigerant leakage, and an inner tube rubber layer is provided thereon. Is used, and a reinforcing yarn layer made of organic fibers such as PET is provided thereon, and further, an EPDM rubber layer having weather resistance is provided thereon (Patent Document 1).

In recent years, the global warming potential of Freon gas R-134a, which is used as a refrigerant in automobile air conditioners, is being considered as a problem. Although the current CFCs R-134a has an ozone depletion coefficient of zero, it has a global warming coefficient of nearly 1500, and the next-generation refrigerant is required to have a global warming coefficient of 150 or less. As alternative refrigerants satisfying this value, R-152a, Fluid-H and the like are listed as candidates in the Freon system, and CO _{2 and the} like are also attracting attention as a natural system.
JP 2007-15245 A

  Air conditioner hoses for automobiles are required to have low permeability to chlorofluorocarbons used as a refrigerant. Currently, nylon resins are mainly used. However, refrigerants listed as representative candidates are expected to increase in environmental temperature. And may not find enough durability. It is also conceivable that the new extreme pressure agent does not have sufficient durability.

  The present invention has been made in view of the above-described conventional situation, and an object of the present invention is to provide a refrigerant transport hose with improved durability against a combined environment with a new refrigerant.

The refrigerant transport hose of the present invention (Claim 1) is a refrigerant transport hose having a gas barrier layer made of a polyamide resin composition, wherein the polyamide resin composition comprises an iodine compound and a total of an iodine compound and a polymer component. 1 to 15% by weight of a polyamide resin composition, wherein the iodine compound is copper iodide and potassium iodide, and the weight ratio of copper iodide and potassium iodide in the polyamide resin composition is 1 / 1 to 1/8, the polyamide resin composition contains a polyolefin-based elastomer, and at least a part of the polyolefin-based elastomer is acid-modified.

The refrigerant transport hose according to claim 2 is characterized in that, in claim 1 , the content of the polyolefin-based elastomer in the polyamide resin composition is 10 to 45% by weight based on the total weight of the polyamide resin composition. It is.

The refrigerant transporting hose according to claim 3, in claim 1 or 2, the outer circumferential side of the gas barrier layer, and is characterized in that the reinforcing layer and the external rubber layer is provided consisting of reinforcing threads .

The refrigerant transporting hose of the present invention is an iodine compound in the polyamide resin composition constituting the gas barrier layer was formulated from 1 to 15% by weight relative to the total of the iodine compound and the polymer component. Thus, durability of the gas barrier layer which consists of this polyamide resin composition improves by mix | blending a predetermined amount or more of an iodine compound with a polyamide resin composition.

The combined use of potassium Yo U of copper iodide as iodine compound at a ratio of 1 / 0.5 / 10 (weight ratio), thereby improving the durability of the gas barrier layer.

  In the present invention, 10 to 45% by weight of a polyolefin-based elastomer may be blended in the polyamide resin composition constituting the gas barrier layer, thereby improving the flexibility and durability of the gas barrier layer.

  The polyolefin-based elastomer may be at least partially acid-modified, thereby improving compatibility with the polyamide resin.

  Hereinafter, embodiments of the refrigerant transport hose of the present invention will be described in detail.

  FIG. 1 is a perspective view for explaining a layer structure of a refrigerant transport hose 1 according to an embodiment. The innermost layer of the refrigerant transport hose 1 is composed of a gas barrier layer 2 made of a polyamide resin composition, and an inner rubber layer 3 is formed on the outer periphery thereof. Hereinafter, a first reinforcing yarn layer 4 and an intermediate rubber layer 5 are sequentially formed. A second reinforcing yarn layer 6 and a jacket rubber layer 7 are formed. The inner diameter of the hose 1 is usually about 6 to 20 mm, particularly about 8 to 19 mm.

  Hereinafter, materials and the like of the layers 2 to 7 will be described.

<Gas barrier layer>
The gas barrier layer 2 is made of a polyamide resin composition in which an iodine compound is blended in an amount of 1% by weight or more based on the total of the iodine compound and the polymer component.
Here, the polymer component in the polyamide resin composition refers to a polyamide resin or a total of polymer components such as a polyamide resin and a polyolefin-based elastomer described later and other resins.

  The polyamide resin used in the present invention is a polyamide resin mainly composed of amino acid, lactam or diamine and dicarboxylic acid. Specific examples of these components include lactams such as ε-caprolactam, enantolactam, ω-laurolactam, amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, tetramethylenediamine, hexa Methylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1 Diamines such as 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis-p-aminocyclohexylmethane, bis-p-aminocyclohexylpropane, isophoronediamine, adipic acid, suberic acid, azelaic acid, zebacic acid , Dodecanedioic acid, 1,4-cyclo Cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, dicarboxylic acids such as dimer acid. These constituent components are used for polymerization alone or in the form of a mixture of two or more, and the resulting poamide resin may be either a homopolymer or a copolymer.

  Polyamide resins (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebamide (nylon 610) are particularly useful as the polyamide resin that is effectively used in the present invention. ), Polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene adipamide / hexamethylene terephthalamide copolymer (nylon 66 / 6T), polycoupleramide / polyhexamethylene adipamide copolymer (Nylon 6/66) may be mentioned, and these may be used alone or in combination of two or more.

  The degree of polymerization of the polyamide is not particularly limited, and a 1% by weight sulfuric acid solution having a relative viscosity at 25 ° C. (hereinafter sometimes simply referred to as “relative viscosity”) in the range of 1.5 to 5.0. It can be used arbitrarily. In addition, in the polyamide resin, the terminal group concentration is adjusted by adding one or more of a monocarboxylic acid compound and / or a dicarboxylic acid compound or a monoamine compound and / or a diamine compound to the polyamide at an arbitrary stage. May be.

  As the iodine compound, copper iodide and / or potassium iodide is suitable.

The content of the polyamide resin composition of the iodine compound, 1 to 15 wt% and preferably by the total of the iodine compound and the polymer component from 1 to 5 wt%. When the compounding amount of the iodine compound is less than 1% by weight, the durability of the gas barrier layer made of the polyamide resin composition is not sufficiently improved. Moreover, even if it mixes exceeding 15 weight%, an effect will not improve any more and it will become high-cost.

As the iodine compound, copper iodide and potassium iodide are used in combination. In this case, the weight ratio of [copper iodide] / [potassium iodide] is 1 / 0.5 to 1/10, preferably 1/1 to more preferably 1/8 shall be the 1 / 2-1 / 6. Thus, durability of the gas barrier layer which consists of the said polyamide resin composition improves by using together copper iodide and potassium iodide.

  In this invention, you may mix | blend polyolefin-type elastomer with this polyamide resin composition. By blending the polyolefin-based elastomer, flexibility and durability of the gas barrier layer composed of the polyamide resin composition can be imparted.

  Examples of the olefin elastomer include ethylene / butene copolymer, EPR (ethylene-propylene copolymer), modified ethylene / butene copolymer, EEA (ethylene-ethyl acrylate copolymer), modified EEA, modified EPR, Modified EPDM (ethylene-propylene-diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), modified SEBS (styrene-ethylene-butylene-styrene copolymer), halogenated isobutylene- Examples thereof include a paramethylstyrene copolymer, an ethylene-acrylic acid modified product, an ethylene-vinyl acetate copolymer, an acid-modified product thereof, and a mixture containing them as a main component. These may be used alone or in combination of two or more.

  As elastomers, those modified with acid anhydrides such as maleic anhydride, alkyl acrylate esters such as glycidyl methacrylate, epoxies and their modified products, etc., should obtain a fine alloy structure based on polyamide resin. This is preferable.

  If the elastomer content in the polyamide resin composition according to the present invention is too small, the effect of improving the flexibility and durability due to the blending of the elastomer cannot be sufficiently obtained, and if it is too much, the gas barrier property is lowered. The content in the polyamide resin composition is preferably 10 to 45% by weight, more preferably 20 to 40% by weight. When the elastomer content in the polyamide resin composition is too large, the sea phase and the island phase are reversed in the sea-island structure described later, and the gas barrier property is remarkably lowered.

When a modified elastomer such as an acid-modified elastomer is used as the elastomer, an effect that less specific energy and a high kneading technique are not required at the time of kneading (dispersion) can be obtained. When the modified elastomer is used as the elastomer, the content of the modified elastomer in the polyamide resin composition is 20% by weight or less, for example, 5 to 20% by weight. % Is preferable.
In particular, in the present invention, it is preferable that 40 to 100% by weight of the elastomer in the polyamide resin composition is an acid-modified elastomer.

In order to make the polyamide resin composition and the elastomer compatible, that is, in a good dispersion state, it is preferable that at least a part of the elastomer is modified with maleic anhydride or the like, in order to obtain a good dispersion form. The average acid value (acid modification rate) of the entire elastomer to be used is preferably 0.8 mg-CH ₃ ONa / g or more.

The higher the acid value of the elastomer, the better the dispersion form, but the viscosity of the polyamide resin composition obtained with an increase in the acid value increases and the molding processability is impaired. For this reason, in order to reduce the increase in viscosity due to the increase in the acid value, the acid value of the elastomer is preferably low in a range where a good dispersion state can be obtained, and the average acid value of the whole elastomer used is 7.5 mg. is preferably not more than -CH ₃ ONa / g.

Moreover, even if the average acid value is the same, when the acid value of the modified elastomer contained in the elastomer to be used is high, the modified elastomer is mixed with the unmodified elastomer, thereby extruding even if the average acid value is lowered. Occasionally, gel-like foreign substances appear due to local overreaction. Therefore, the acid value of the modified elastomer to be used is preferably 15.0 mg-CH ₃ ONa / g or less.

  Thus, by blending an elastomer with a polyamide resin composition, flexibility and durability are improved, but a decrease in gas barrier properties is unavoidable. However, by adopting a fine alloy structure of polyamide resin and elastomer, the island phase of the elastomer is dispersed in the sea phase of the polyamide resin, and the polyamide resin is dispersed in the form of dots in the island phase of the elastomer. With such a structure, a decrease in gas barrier properties due to the blending of the elastomer can be suppressed, which is preferable.

  In particular, the ratio of the polyamide resin phase that is scattered in the island phase of the elastomer to the polyamide resin (the total of the polyamide resin that constitutes the sea phase and the polyamide resin phase that is scattered in the island phase of the elastomer) (Hereinafter, the ratio is referred to as “spot dispersion”) is preferably about 5 to 40% by weight. If this proportion is less than 5% by weight, it is not possible to sufficiently obtain the effect of the presence of the polyamide resin phase in the form of scattered dots in the island phase of the elastomer. There is a possibility that the polyamide resin phase becomes too small and the gas barrier property is lowered.

  The size of the elastomeric island phase and the size of the polyamide resin phase in the elastomeric island phase are approximately 0.1 to 3.0 μm for the elastomeric island phase and 0.5 for the polyamide resin phase. It is preferable that it is about -2.0 micrometers.

  The polyamide resin composition used in the present invention may contain a resin component other than the polyamide resin as a resin component. In that case, 70% by weight or more of the total polymer component in the refrigerant transport hose is 70% by weight or more. A polyamide resin is preferred for ensuring gas barrier properties.

  Examples of other resin components in this case include ethylene / vinyl alcohol resin.

  In addition, the polyamide resin composition according to the present invention includes other additives, that is, a lubricant, an antistatic agent, an anti-aging agent, an antioxidant, a coloring agent, a crystal nucleating agent, a filler, a reinforcing material, a heat-resistant agent, and light resistance. Agents and the like can also be added.

The thickness of the gas barrier layer 1 made of such a polyamide resin composition is preferably thicker from the viewpoint of gas barrier properties. However, as the film thickness increases, the flexibility as a hose decreases.
Therefore, the film thickness of the gas barrier layer 2 is preferably 50 to 400 μm, particularly preferably 100 to 300 μm.

  In the refrigerant transport hose of the present invention, an inner rubber layer may be further formed as an innermost layer on the inner layer of the gas barrier layer 2 in the refrigerant transport hose 10 of FIG.

  There is no restriction | limiting in particular about the other structure of the refrigerant | coolant transport hose of this invention, The structure of the normal refrigerant | coolant transport hose is employable as follows.

<Inner rubber layer 3, outer rubber layer 7 and intermediate rubber layer 5>
As the rubber constituting the inner rubber layer 3 and the outer rubber layer 7, butyl rubber (IIR), chlorinated butyl rubber (C1-IIR), chlorinated polyethylene, chlorosulfonated polyethylene, brominated butyl rubber (Br-IIR), Isobutylene-bromoparamethylstyrene copolymer, EPR (ethylene-propylene copolymer), EPDM (ethylene-propylene-diene terpolymer), NBR (acrylonitrile butadiene rubber), CR (chloroprene rubber), hydrogenated NBR Acrylic rubber, ethylene acrylic rubber (AEM), a blend of two or more of these rubbers, or a blend with a polymer based on these rubbers, preferably butyl rubber or EPDM rubber. . These rubbers can be applied with compounding recipes such as commonly used fillers, processing aids, anti-aging agents, vulcanizing agents, and vulcanization accelerators.

  The rubber type of the inner rubber layer 3 and the rubber type of the jacket rubber layer 7 may be the same or different.

  Moreover, the rubber | gum of the intermediate | middle rubber layer 5 should just have the adhesiveness with the inner-layer rubber layer 2 and the jacket rubber layer 7, and there is no restriction | limiting in particular.

  The thickness of the inner rubber layer 3 is preferably about 0.5 to 4 mm from the viewpoint of flexibility. The thickness of the intermediate rubber layer 5 is preferably about 0.1 to 0.6 mm, and the thickness of the outer rubber layer 7 is preferably about 0.5 to 2 mm.

<Reinforcing thread layers 4, 6>
The first reinforcing yarn layer 4 is obtained by winding a reinforcing yarn in a spiral shape, and the second reinforcing yarn layer 6 is obtained by winding a reinforcing yarn in a spiral shape in the opposite direction to the first reinforcing yarn layer 4. is there.

  The material of the reinforcing yarn is not particularly limited as long as it is usually used. In general, polyester, wholly aromatic polyester, nylon, vinylon, rayon, aramid, polyarylate, polyethylene naphthalate and blended yarns thereof are used.

<Method for manufacturing refrigerant transport hose>
Such a refrigerant transport hose according to the present invention is formed by extruding the material of the gas barrier layer 2 and the inner rubber layer 3 to a predetermined thickness on a mandrel and laminating them on the mandrel, and winding the reinforcing yarn layer 4 on the intermediate rubber layer. 5 is extruded and laminated, the reinforcing yarn layer 6 is wound, then the outer rubber layer 7 is extruded and laminated, and then vulcanized at 140 to 170 ° C. for 30 to 120 minutes.

  Below, the test example equivalent to an Example and a comparative example performed about the polyamide-type resin piece is demonstrated.

  Each material was kneaded according to the formulation shown in Table 1 to produce test polyamide resin pieces. In the kneading, a twin-screw kneader manufactured by Toyo Seiki Co., Ltd. was used and kneaded at a temperature of 230 ° C. above the melting point of the polyamide resin.

  The materials used for the production of the test polyamide resin pieces are as follows, and the composition of the materials is as shown in Tables 1 and 2.

Polyamide 6: 6 nylon “1022B” manufactured by Ube Industries, Ltd.
Elastomer: α-olefin polymer (ethylene / butene copolymer) manufactured by Mitsui Chemicals, Inc.
) "Toughmer A-1050S"
Maleic acid-modified elastomer: maleic acid-modified α-olefin polymer manufactured by Mitsui Chemicals, Inc.
(Ethylene / Butene Copolymer) “Toughmer MH7010”

<Evaluation method>
Each polyamide resin piece was aged by the following method, and the tensile physical properties and gas permeability before and after aging were evaluated. The results are shown in Tables 1 and 2.

1 If there is moisture in the pressure vessel, put 1% water in the vessel.
2 Put a polyamide resin piece of width 10 × length 50 mm × thickness 0.1 mm.
3 Add 100 cc of polyalkylene glycol oil.
4 Freeze the pressure vessel for 15 minutes and then evacuate the pressure vessel for 5 minutes.
5 Put 100 cc of R-134a as a refrigerant 6 Leave in a high temperature bath at 150 ° C. for 4 weeks.
7 Take out the polyamide resin piece from the container and measure the tensile properties (4% elongation modulus index), strength retention, elongation at break and gas permeability.

  In Tables 1 and 2, dispersibility is the result of observing a sample surface-treated with phosphotungstic acid using an electron microscope (SEM). The dispersion particle size of the elastomer is 3 μm or less is OK, and the particle size exceeding 3 μm is NG. did.

  The 4% elongation modulus index was expressed as an index relative to Comparative Example 1 (100) by using a tensile tester manufactured by Toyo Seiki Co., Ltd., measuring the modulus of elasticity by stretching at a tensile speed of 50 mm / min.

  The gas permeability index was expressed as an index relative to Comparative Example 1 (100) by measuring the He gas permeability coefficient at 100 ° C. with an absolute differential pressure of 226 cmHg using a gas permeability tester manufactured by GTR Tech.

  The strength retention after aging was measured by using a tensile tester manufactured by Toyo Seiki Co., Ltd., measuring the breaking strength by stretching at a pulling speed of 50 mm / min, and expressed as a percentage before aging.

  The elongation at break after aging was measured by using a tensile tester manufactured by Toyo Seiki Co., Ltd., measuring the elongation at break by stretching at a pulling speed of 50 mm / min, and expressed as a percentage with respect to that before aging.

Reference Example 1 in which copper iodide and potassium iodide are blended in an amount of 1% by weight or more based on the total of the polymer components as shown in Table 1, and the weight ratio of copper iodide / potassium iodide is 1 / 1.5. According to -4 and Examples 5-6 , the strength retention after aging and the elongation at break after aging are high.

It is a perspective view which shows embodiment of the hose for refrigerant | coolant transportation of this invention.

DESCRIPTION OF SYMBOLS 1 Refrigerant transport hose 2 Gas barrier layer 3 Inner rubber layer 4,6 Reinforcing thread layer 5 Intermediate rubber layer 7 Outer rubber layer

Claims (3)

In a refrigerant transport hose having a gas barrier layer made of a polyamide resin composition,
The polyamide resin composition is a polyamide resin composition containing the iodine compound in an amount of 1 to 15% by weight based on the total of the iodine compound and the polymer component,
The iodine compound is copper iodide and potassium iodide, and the weight ratio of copper iodide and potassium iodide in the polyamide resin composition is 1/1 to 1/8,
The polyamide resin composition contains a polyolefin-based elastomer,
A refrigerant transport hose characterized in that at least a part of the polyolefin elastomer is acid-modified.   The refrigerant transport hose according to claim 1, wherein the content of the polyolefin-based elastomer in the polyamide resin composition is 10 to 45% by weight with respect to the total weight of the polyamide resin composition.   3. The refrigerant transport hose according to claim 1, wherein a reinforcing layer made of a reinforcing yarn and a jacket rubber layer are provided on the outer peripheral side of the gas barrier layer.

Images