JP2007032725A - Hose for transporting refrigerant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose for transporting refrigerant superior in gas barrier property and flexibility, and further superior in impulse-proof property after long-term heat aging, and durability performances in a vibration durability test after impulse test and a dynamic durability test after heat aging. <P>SOLUTION: This hose has a resin layer composed of a poly ketone resin as an innermost layer. As the poly ketone resin has superior gas barrier property, gas barrier property and flexibility can be significantly improved by forming the poly ketone layer as the innermost layer, and the hose for transporting the refrigerant, superior in the impulse-proof performance after long-term heat aging, and the durability performances in the vibration durability test after impulse test, the dynamic durability test after heat aging, or the like can be provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigerant transport hose excellent in gas barrier properties (refrigerant permeability), dynamic durability, and flexibility.

  Refrigerant transport hoses used for piping and the like of automobile air conditioners are roughly classified into high pressure lines and low pressure lines. The high-pressure line is a line that supplies high-temperature refrigerant compressed into a gas-liquid mixture by a compressor to the condenser at high pressure. The low-pressure line is a line for returning the low-pressure / low-temperature refrigerant evaporated by the evaporator to the compressor.

  The refrigerant transport hose has excellent gas barrier properties that can reliably prevent the leakage of refrigerant (Freon), flexibility to ensure the routing of the refrigerant transport hose in narrow spaces, and durability Properties such as aging resistance, impact resistance, and mechanical strength are required, but especially for gas barrier properties, the amount of refrigerant leakage in the high-pressure line is significant due to its mechanism, so high gas barrier properties are required. It has been.

  The conventional refrigerant transport hose has an innermost layer made of a composite resin obtained by adding an elastomer as a flexibility-imparting agent to a polyamide-based resin such as polyamide 6 (nylon 6) in order to ensure gas barrier properties and flexibility. It is arranged as a gas barrier layer and has a multilayer structure in which a rubber layer is coated on the outer periphery. In the innermost layer, although the flexibility is improved by blending the elastomer, the gas barrier property of the elastomer itself is inferior to that of polyamide, and as a result, the gas barrier property of the innermost layer made of the composite resin is impaired.

  Therefore, in order to solve this problem, the present applicant firstly used a refrigerant transport hose excellent in gas barrier properties and flexibility, in which the innermost layer was polyamide 6:58 to 72 parts by weight and elastomer: 42 to 28 parts by weight. Proposing a refrigerant transport hose comprising a sea-island-structured resin layer in which the sea phase is polyamide 6, the island phase is elastomer, and the polyamide 6 is dispersed in the island phase of the elastomer (Japanese Patent Laid-Open No. 2000-120944).

  In this refrigerant transport hose, since the innermost resin layer has the polyamide 6 phase scattered in the form of scattered dots in the elastomeric island phase, the elastomeric island phase is present inside the original volume of the elastomer. The apparent volume fraction increases by the amount of the polyamide 6 phase. Thus, when the apparent volume fraction of the island phase of the elastomer is increased, the same effect of improving the flexibility as when the amount of the elastomer is increased can be obtained. For this reason, the blending amount of the actual elastomer can be kept low, and therefore a good flexibility improvement effect can be obtained without causing a decrease in gas barrier properties due to the blending of the elastomer.

  In recent years, environmental problems have been greatly taken up, and the global warming potential of Freon gas R-134a, which is used as a refrigerant in automobile coolers, is becoming a problem. The current Freon gas R-134a has a global warming potential of nearly 1500 although its ozone depletion coefficient is zero, and a significant reduction in the amount of leakage has been demanded.

In response to this trend, a new fluorinated gas emission regulation proposal was adopted by the EU around the middle of 2003, and in the automobile OE companies, a significant reduction in the amount of refrigerant leakage became a major concern. The resin layer having polyamide as a main component as described in the publication No. 1 has insufficient gas barrier performance, and a drastic review has been necessary to comply with EU regulations.
JP 2000-120944 A

  The present invention has been made in view of the above circumstances, and is excellent in gas barrier properties and flexibility, and has an impulse resistance performance after long-term heat aging, a vibration durability test after an impulse test, and a dynamic durability test after heat aging. An object of the present invention is to provide a refrigerant transport hose having excellent durability performance.

  As a result of intensive studies to solve the above-mentioned problems, the inventor has paid attention to a polyketone resin excellent in gas barrier performance, and by making the resin layer containing the polyketone resin the innermost layer, the thinness does not impair the flexibility. Sufficient gas barrier property can be obtained in the innermost layer, and the gas barrier property and flexibility are remarkably excellent, and the impulse resistance after long-term heat aging, vibration durability test after impulse test, dynamic durability test after heat aging, etc. It has been found that a refrigerant transport hose excellent in durability can be realized.

  The present invention has been achieved based on such knowledge, and the gist thereof is as follows.

[1] A refrigerant transport hose comprising a resin layer containing a polyketone resin as an innermost layer.

[2] The refrigerant transport hose according to [1], wherein the innermost layer is a polyketone resin layer.

[3] The refrigerant transport hose according to [1] or [2], wherein the innermost layer has a thickness of 20 to 50 μm.

（（Ｉ）式中、Ｒはエチレン性不飽和化合物由来の連結基であり、各繰り返し単位において、同一であっても異なっていても良い。） [4] A refrigerant transport hose according to [1] to [3], wherein the polyketone resin is a polyketone resin represented by the following general formula (I).

(In the formula (I), R is a linking group derived from an ethylenically unsaturated compound, and each repeating unit may be the same or different.)

[5] The refrigerant transport hose according to [4], wherein R in the general formula (I) is a connecting group derived from ethylene.

[6] In [4] or [5], the polymerization degree of the polyketone resin is a polymerization degree in which the solution viscosity measured in m-cresol at 60 ° C. is in the range of 1.0 to 10.0 dL / g. A refrigerant transport hose.

  According to the present invention, a polyketone-based composite resin excellent in gas barrier properties, flexibility, and durability is realized by a polyketone resin excellent in gas barrier properties. Therefore, according to the refrigerant transport hose of the present invention, the gas barrier property and flexibility are remarkably excellent, such as impulse resistance after long-term heat aging, vibration durability test after impulse test, dynamic durability test after heat aging, etc. A refrigerant transport hose having excellent durability performance is provided (claims 1 and 2).

  The film thickness of the innermost layer made of this polyketone resin or polyketone-based composite resin is preferably 20 to 50 μm (Claim 3).

（（Ｉ）式中、Ｒはエチレン性不飽和化合物由来の連結基であり、各繰り返し単位において、同一であっても異なっていても良い。） In the present invention, the polyketone resin is preferably a polyketone resin represented by the following general formula (I) (Claim 4), R is a connecting group derived from ethylene (Claim 5), and the degree of polymerization is m. -It is preferable that it is the polymerization degree which the solution viscosity measured at 60 degreeC in the range of 1.0-10.0dL / g in cresol (Claim 6).

(In the formula (I), R is a linking group derived from an ethylenically unsaturated compound, and each repeating unit may be the same or different.)

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

  First, the polyketone resin used in the present invention will be described.

（（Ｉ）式中、Ｒはエチレン性不飽和化合物由来の連結基であり、各繰り返し単位において、同一であっても異なっていても良い。） The polyketone resin used in the present invention is preferably a polyketone resin represented by the following general formula (I).

(In the formula (I), R is a linking group derived from an ethylenically unsaturated compound, and each repeating unit may be the same or different.)

  The polyketone is an alternating copolymer in which CO units (carbonyl group) and units derived from an ethylenically unsaturated compound are arranged in the molecule, that is, next to each CO unit in the polymer chain, for example, an ethylene unit, etc. This structure has one olefin unit. The polyketone may be a copolymer of carbon monoxide and one specific ethylenically unsaturated compound, or a copolymer of carbon monoxide and two or more ethylenically unsaturated compounds. Also good.

  Examples of the ethylenically unsaturated compound forming R in (I) include unsaturated hydrocarbon compounds such as ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, dodecene, styrene, methyl acrylate, Examples thereof include unsaturated carboxylic acids such as methyl methacrylate, vinyl acetate, and undecenoic acid or derivatives thereof, as well as undecenol, 6-chlorohexene, N-vinylpyrrolidone, and diethyl ester of sulphonylphosphonic acid. These may be used alone or in combination of two or more, but in particular from the viewpoint of the mechanical properties and heat resistance of the polymer, a polyketone using an ethylenically unsaturated compound mainly composed of ethylene Is preferred.

  When ethylene and another ethylenically unsaturated compound are used in combination as the ethylenically unsaturated compound constituting the polyketone, ethylene is preferably used in an amount of 80 mol% or more based on the total ethylenically unsaturated compound. . If this ratio is less than 80 mol%, the melting point of the resulting polymer will be 200 ° C. or lower, and the resulting polyketone resin may have insufficient heat resistance. In view of the mechanical properties and heat resistance of the polyketone resin, the amount of ethylene used is preferably 90 mol% or more with respect to the total ethylenically unsaturated compound.

  The polyketone can be produced according to a known method, for example, a method described in European Patent Publication Nos. 121965, 213671, 229408 and US Pat. No. 3,914,391.

  As for the polymerization degree of the polyketone, the solution viscosity measured at 60 ° C. in m-cresol is preferably in the range of 1.0 to 10.0 dL / g. If the solution viscosity is less than 1.0 dL / g, the resulting polyketone resin may have insufficient mechanical strength and gas barrier properties. From the viewpoint of the dynamic strength and gas barrier properties of the polyketone resin, the solution viscosity is 1.2 dL / g. The above is more preferable. On the other hand, when the solution viscosity exceeds 10.0 dL / g, the flexibility may be poor, and from the viewpoint of flexibility, the solution viscosity is more preferably 5.0 dL / g or less. In view of the mechanical strength, gas barrier property, flexibility and the like of the polyketone resin, the solution viscosity is particularly preferably in the range of 1.3 to 4.0 dL / g.

  In this invention, polyketone resin may be used individually by 1 type, and may use 2 or more types together.

  In the present invention, the innermost layer may be composed only of a polyketone resin, but the polyketone resin alone may not ensure sufficient flexibility as a refrigerant transport hose. May be composed of a polyketone-based composite resin in which an elastomer as a flexibility-imparting agent is added to a polyketone resin to form a polymer alloy.

  As the elastomer, ethylene / butene copolymer, modified ethylene / butene copolymer, EEA (ethylene-ethyl acrylate polymer), modified EEA, modified EPR (ethylene-propylene copolymer), modified EPDM (ethylene-propylene-) Diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), SEBS (styrene-ethylene-butylene-styrene copolymer) and acid-modified products thereof, and their main components. A mixture etc. are mentioned. These may be used alone or in combination of two or more.

  If the elastomer content in the polyketone-based composite resin of 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 too much, the gas barrier property decreases. The content in the polyketone composite resin is preferably 30% by weight or less, more preferably 10 to 30% by weight, and particularly preferably 25 to 28% by weight. If the content of the elastomer in the polyketone composite resin 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.

  Although the flexibility is improved by blending the elastomer with the polyketone resin as described above, the gas barrier property is inevitably lowered. However, by adopting a fine alloy structure of polyketone resin and elastomer, in particular, the island phase of elastomer is dispersed in the sea phase of polyketone resin, and the polyketone resin is dispersed in the form of dots in the island phase of this elastomer. With such a structure, a decrease in gas barrier properties due to the blending of the elastomer can be suppressed, which is preferable.

  The polyketone composite resin of the present invention may contain a resin component other than the polyketone resin as a resin component. In that case, 70% by weight or more of the total resin component in the polyketone composite resin is polyketone. A resin is preferable for ensuring gas barrier properties.

  Examples of other resin components in this case include one or more of polyamide resins.

  Moreover, you may add additives, such as anti-aging agent and an oxidation deterioration agent, to the polyketone resin or polyketone type composite resin which comprises the innermost layer of the refrigerant | coolant transport hose of this invention.

The polyketone composite resin having a sea-island structure as described above can be produced, for example, by the following method (1) or (2).
(1) A method in which a polyketone resin and an elastomer are kneaded at a predetermined mixing ratio to form a master batch, and then the master batch and the polyketone resin are kneaded.
(2) A method of melt kneading a polyketone resin and an elastomer blend by high shear.

  Next, the refrigerant transport hose of the present invention having the innermost layer made of such polyketone resin or polyketone-based composite resin will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of the refrigerant transport hose of the present invention.

  In the refrigerant transport hose 10 of FIG. 1, the reinforcing yarn layer 3 is formed between the inner rubber layer 2 and the outer rubber 5, and the resin layer 1 is formed on the inner periphery of the inner rubber layer 2. The reinforcing yarn layer 3 includes a first reinforcing yarn layer 3A in which the reinforcing yarn is wound in a spiral shape, and a second reinforcing yarn layer 3B in which the reinforcing yarn is wound in a spiral shape in a direction opposite to the first reinforcing yarn layer 3A. The intermediate rubber layer 4 is laminated. An adhesive layer may be provided between the resin layer 1 and the inner tube rubber layer 2 as necessary.

  The resin layer 1 is composed of a polyketone resin or a polyketone-based composite resin. The thickness of the resin layer 1 is preferably as thick as possible in terms of the gas barrier property and durability of the hose. On the other hand, when the thickness of the resin layer 1 is increased, flexibility and impulse resistance as a hose are sacrificed. Therefore, although the film thickness of the resin layer 1 varies depending on the content of the elastomer, it is preferably 20 to 50 μm, particularly preferably 30 to 40 μm.

  In particular, since the polyketone resin is remarkably excellent in gas barrier properties, flexibility and impulse resistance can be ensured by reducing the film thickness for securing the gas barrier property of the hose to 50 μm or less.

  The resin layer 1 made of the polyketone resin or polyketone-based composite resin of the present invention can be used as an innermost layer of a refrigerant transport hose even in a single layer structure, as an impulse resistance after a long-term heat aging, a vibration durability test after an impulse test, a heat aging Since it is possible to provide a refrigerant transport hose excellent in durability performance such as later dynamic durability test and gas barrier performance, such a refrigerant transport hose using the polyketone resin of the present invention, Co-extrusion for forming a multi-layer structure is not necessary and can be easily manufactured.

  However, in the refrigerant transport hose of the present invention, the resin layer 1 does not necessarily have a single-layer structure as shown in FIG. 1, and the total thickness of the hose is excessively increased to impair flexibility and increase cost and weight. A laminated resin layer may be used as long as no increase is caused.

  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.

  For example, as the rubber constituting the inner tube rubber layer 2 and the jacket rubber 5, butyl rubber (IIR), chlorinated butyl rubber (C1-IIR), chlorinated polyethylene, chlorosulfonated polyethylene, brominated butyl rubber (Br-IIR) are generally used. ), Isobutylene-bromoparamethylstyrene copolymer, EPR (ethylene-propylene copolymer), EPDM (ethylene-propylene-diene terpolymer), NBR (acrylonitrile butadiene rubber), CR (chloroprene rubber), hydrogen Addition NBR, acrylic rubber, a blend of two or more of these rubbers, or a blend with a polymer based on these rubbers, preferably a butyl rubber or EPDM rubber is used. 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 2 and the rubber type of the jacket rubber 5 may be the same type or different types.

  Moreover, the rubber | gum of the intermediate | middle rubber layer 4 should just have the adhesiveness with the inner tube | pipe rubber layer 2 and the jacket rubber 5, and there is no restriction | limiting in particular.

  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.

  The thickness of the inner tube rubber layer 2 is preferably about 0.8 to 4 mm from the viewpoint of flexibility. Furthermore, it is preferable that the thickness of the intermediate rubber layer 4 including the reinforcing yarn is about 0.5 to 5 mm, and the thickness of the outer rubber layer 5 is about 1 to 2 mm.

  Such a refrigerant transport hose of the present invention is manufactured by extruding and laminating the material of each constituent layer to a predetermined thickness on a mandrel and vulcanizing at 140 to 170 ° C. for 30 to 120 minutes according to a conventional method. can do.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

  The rubber ratios of the inner rubber layer, the intermediate rubber layer, and the outer rubber layer used in the following examples and comparative examples are as shown in Tables 1 to 3 below.

Examples 1 and 2 and Comparative Example 1
A refrigerant transport hose having the structure shown in FIG. 1 was manufactured by the following procedure using the following materials for the innermost resin layer.
Polyamide resin: 6 nylon “1022B” manufactured by Ube Industries, Ltd.
Polyketone resin: In the general formula (I), R is ethylene, and in m-cresol,
A polymer having a degree of polymerization showing a solution viscosity of 4.0 dL / g measured at 60 ° C.
T resin

  After extruding on a mandrel having a diameter of 11 mm with a resin composition shown in Table 4 to form a resin layer 1 having a thickness shown in Table 1, the inner layer rubber shown in Table 1 was extruded to a thickness of 1.6 mm. On top of this, 22 polyester reinforcing yarns with a number of times of 10/10 cm at 1100 dtex / 4 were drawn and wound in a spiral shape, and the intermediate rubber shown in Table 2 was extruded to a thickness of 0.3 mm on this reinforcing yarn layer. On top of that, 22 polyester reinforcing yarns having a number of times of 10/10 cm at 1100 dtex / 4 were drawn and wound in a spiral shape in the opposite direction. Next, the jacket rubber shown in Table 3 was extruded to a thickness of 1.2 mm and vulcanized at 150 ° C. for 45 minutes to obtain a refrigerant transport hose having an inner diameter of 11 mm and an outer diameter of 19 mm.

  The obtained refrigerant transport hose was examined for flexibility, Freon gas barrier properties and impulse resistance by the following methods, and the results are shown in Table 4.

Flexibility:
It was measured by a three-point bending test.

  The center was pushed by a load cell at 500 mm / min with a span of 200 mm between the rollers, and the indentation load was measured. The smaller this value, the better the flexibility.

Freon gas barrier properties:
A predetermined amount of Freon gas was filled in the hose and left in a constant temperature bath at 90 ° C., and the weight decreased was measured every 24 hours. After the weight loss per unit time was stabilized, the amount of leakage per 1 m / day of the hose was measured and indicated as an index when the amount of leakage in Comparative Example 1 was set to 100. The lower this value, the better the gas barrier property.

Impulse resistance:
It investigated by the repeated pressurization test.

  Under the conditions of 0 to 140 ° C., 0 to 3.3 MPa, and 20 CPM, the inner surface of the hose was repeatedly pressurized with PAG oil, and it was confirmed that the hose was cracked and the airtightness was ensured. The numerical values in the table are the number of repetitions (10,000 times) until the airtightness is impaired, and the larger the value, the better the impulse resistance.

  From Table 4, according to the polyketone resin, it is possible to obtain a refrigerant transport hose excellent in gas barrier properties, and in particular, to ensure flexibility and impulse resistance, the thickness of the polyketone resin layer should be 50 μm or less. It turns out that is preferable.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin layer 2 Inner tube rubber layer 3 Reinforcement thread layer 3A 1st reinforcement thread layer 3B 2nd reinforcement thread layer 4 Intermediate rubber layer 5 Jacket rubber 10 Refrigerant transport hose

Claims (6)

  A refrigerant transport hose comprising a resin layer containing a polyketone resin as an innermost layer.   The refrigerant transport hose according to claim 1, wherein the innermost layer is a polyketone resin layer.   The refrigerant transport hose according to claim 1 or 2, wherein the innermost layer has a thickness of 20 to 50 µm. The refrigerant transport hose according to any one of claims 1 to 3, wherein the polyketone resin is a polyketone resin represented by the following general formula (I).

(In the formula (I), R is a linking group derived from an ethylenically unsaturated compound, and each repeating unit may be the same or different.)   5. The refrigerant transport hose according to claim 4, wherein R in the general formula (I) is a connecting group derived from ethylene.   The polymerization degree of the polyketone resin according to claim 4 or 5, wherein the solution viscosity measured in m-cresol at 60 ° C is in the range of 1.0 to 10.0 dL / g. Refrigerant transport hose.

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