JP5424716B2 - Polyamide resin composition, method for producing the same, and refrigerant transport hose - Google Patents

Description

  The present invention relates to a polyamide resin composition suitable as a resin composition for forming a gas barrier layer of a refrigerant transport hose, a method for producing the same, and a refrigerant transport hose having a gas barrier layer made of the 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, rubber hoses with excellent vibration absorption performance are used in automotive air conditioner piping. The rubber hose has a gas barrier property in the innermost layer to prevent refrigerant leakage. A polyamide resin layer excellent in vibration durability such as impulse resistance is provided, an inner tube rubber layer is provided thereon, a reinforcing yarn layer made of organic fibers such as PET is provided thereon, and further thereon A structure in which an EPDM rubber layer having weather resistance is arranged is used (Japanese Patent Laid-Open No. 2007-15245).

  A refrigerant transport hose is also proposed in which a polyolefin-based elastomer is blended as a flexibility-imparting agent in the polyamide resin constituting the innermost gas barrier layer to impart refrigerant permeation resistance and flexibility (Japanese Patent Laid-Open No. 2000-120944). Issue gazette).

However, polyamide resins have a problem of deterioration due to refrigerants such as CFCs and oil from compressors, and this problem cannot be solved even by blending polyolefin elastomers. For this reason, conventional refrigerant transport hoses are durable. There are still issues to be addressed.
For example, when an acidic component is present even in a small amount in an air conditioner system, the polyamide resin composition may be significantly deteriorated by the acidic component under high temperature / high pressure actual use conditions and may not be able to be used. As this acidic component, an extreme pressure agent contained in compressor oil sealed together with the refrigerant can be considered. For this reason, depending on the type of oil used in the air conditioner and the environmental conditions, the conventional refrigerant transport hose may not be practically durable and may not be usable.

  In order to prevent the deterioration of the gas barrier layer made of such a polyamide resin composition due to refrigerant or compressor oil and to increase the durability of the refrigerant transport hose, the present applicant has first as a polyamide resin composition for gas barrier layer formation, The thing which mix | blended 1 type, or 2 or more types of metal compounds chosen from the group which consists of a hydroxide of a bivalent or trivalent metal, an oxide, and carbonate in a predetermined ratio was proposed (Japanese Patent Application No. 2009-077987). (Hereinafter referred to as “prior application”).

In the case of the polyamide resin composition of the prior application, by blending a specific metal compound in a predetermined ratio, deterioration due to the refrigerant or compressor oil of the gas barrier layer made of this polyamide resin composition can be effectively suppressed or prevented (hereinafter referred to as the following). The suppression or prevention is simply referred to as “prevention”), and the durability can be enhanced.
Although the details of the mechanism of the effect of preventing the deterioration of the polyamide resin composition by the refrigerant or compressor oil due to this specific metal compound are not clear, the metal compound blended in the polyamide resin composition is an acid acceptor, halogen acceptor, etc. It is presumed that the effect of preventing deterioration of the polyamide resin composition is manifested by the metal compound trapping deterioration factors such as acid components and halogen components contained in the refrigerant and oil.

  For this reason, the refrigerant transport hose of the prior application exhibits excellent durability performance without being affected by the oil used or the environment in the system used, and can be used stably and safely over a long period of time.

  Incidentally, as a method for producing a polyamide resin composition containing a flame retardant comprising a halogenated organic compound, Japanese Patent Publication No. 62-13380 discloses a low melting point polyamide master batch prepared by mixing a flame retardant with a low melting point polyamide in advance. And the method of mixing this low melting point polyamide masterbatch with high melting point polyamide is proposed. This method mixes a flame retardant with a high melting point polyamide as a master batch of a low melting point polyamide in order to prevent deterioration due to local overheating caused by a high shear force when the flame retardant is directly mixed with the high melting point polyamide. It does not suggest any method for mixing the above-mentioned specific metal compound into a polyamide resin composition containing a polyamide resin and a polyolefin-based elastomer.

JP 2007-15245 A JP 2000-120944 A Japanese Patent Application No. 2009-079487 Japanese Patent Publication No.62-13380

  In the case of the polyamide resin composition for gas barrier layer formation of the prior application, the deterioration of the gas barrier layer of the refrigerant transport hose by the refrigerant or the compressor oil is prevented by blending a specific metal compound. It is desired to further improve the durability by further effectively acting.

The present invention provides a refrigerant transport hose that is more durable and exhibits the effect of preventing deterioration by the specific metal compound in the polyamide resin composition for forming a gas barrier layer of the refrigerant transport hose of the prior application. It is an object to provide a polyamide resin composition that can be provided.
Another object of the present invention is to provide a refrigerant transport hose having a gas barrier layer made of the polyamide resin composition and having excellent durability performance.

The method for producing a polyamide resin composition of the present invention (Claim 1) comprises (a) a polyamide resin, (b) a polyolefin-based elastomer, (c) a divalent or trivalent metal hydroxide, oxide, and A first kneading step of kneading (c) a metal compound and (a) a polyamide resin in a method for producing a polyamide resin composition containing one or more metal compounds selected from the group consisting of carbonates; A method for producing a polyamide resin composition comprising a kneaded product obtained in the first kneading step and (b) a second kneading step for kneading the polyolefin-based elastomer , wherein the polyamide resin composition comprises: The ratio of the (c) metal compound to the total of the polymer component and (c) metal compound is 1 to 10% by weight, and at least a part of the polyolefin elastomer is acid-modified. It is characterized in.

Method for producing 請 Motomeko 2 of polyamide resin composition is characterized by Oite to claim 1, wherein (c) the metal compound is a hydrotalcite.

The method for producing a polyamide resin composition according to claim 3 is the method according to claim 1 or 2 , wherein 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 characterized by that .

The polyamide resin composition of the present invention (invention 4 ) is manufactured by the method for manufacturing a polyamide resin composition according to any one of claims 1 to 3 .

A polyamide resin composition according to a fifth aspect is the polyamide resin composition for forming a gas barrier layer of a refrigerant transport hose according to the fourth aspect.

The refrigerant transport hose of the present invention (invention 6 ) is a refrigerant transport hose having a gas barrier layer made of a polyamide resin composition, wherein the polyamide resin composition is the polyamide resin composition according to claim 4 or 5. It is characterized by that.

A refrigerant transport hose according to a seventh aspect is characterized in that, in the sixth aspect , a reinforcing layer made of a reinforcing yarn and an outer rubber layer are provided on the outer peripheral side of the gas barrier layer.

  According to the method for producing a polyamide resin composition of the present invention, a polyamide resin and a metal compound are kneaded in advance in producing a polyamide resin composition containing a polyamide resin, a polyolefin-based elastomer, and a specific metal compound. By kneading the polyolefin elastomer in the kneaded product, the effect of preventing the deterioration of the polyamide resin by the metal compound can be more effectively acted. Therefore, by using this polyamide resin composition, it is possible to realize a refrigerant transport hose that has no problem of deterioration of the gas barrier layer due to the refrigerant or the compressor oil and whose durability is further improved (claim 1).

  That is, as a result of further investigations on the method for producing a polyolefin-based elastomer-containing polyamide resin composition containing a metal compound such as hydrotalcite proposed in the prior application, the present inventors have determined that the metal compound depends on the kneading procedure. There is a difference in the effect of preventing deterioration, when the metal compound is kneaded in advance with the polyamide resin and then the polyolefin-based elastomer is kneaded at once, or when the metal compound is pre-kneaded with the polyolefin-based elastomer and then the polyamide resin It has been found that the effect of preventing deterioration due to the metal compound is more effectively exhibited than when the metal compound is kneaded or when the metal compound is kneaded with the polymer alloy of the polyamide resin and the polyolefin elastomer.

The effect of this kneading procedure is as follows. That is, as will be described later, in a resin composition of a polyamide resin and a polyolefin elastomer, the polyamide resin and the polyolefin elastomer preferably have a fine alloy structure, and the island phase of the polyolefin elastomer is in the sea phase of the polyamide resin. Is dispersed. Such deterioration of the polyolefin-based elastomer-containing polyamide resin composition due to the refrigerant or the compressor oil is mainly caused by deterioration due to the acidic component of the polyamide resin of the composition.
According to the present invention, in a resin composition obtained by kneading a metal compound in advance with a polyamide resin and then kneading a polyolefin-based elastomer, the metal compound is mainly present in the polyamide resin phase, and the deterioration of the polyamide resin due to the metal compound is prevented. The action, that is, the action of the metal compound trapping the deterioration factor substances of the polyamide resin such as the acid component and the halogen component contained in the refrigerant and oil, functions directly and effectively in the polyamide resin phase.

  On the other hand, when the metal compound is kneaded after kneading the polyamide resin and the polyolefin elastomer, when the polyamide resin is kneaded after kneading the polyolefin elastomer and the metal compound in advance, or when these are kneaded simultaneously In this case, the metal compound is mainly present in the polyolefin elastomer phase having low viscosity and excellent kneadability, and the effect of preventing the deterioration of the polyamide resin by the metal compound can be directly and effectively acted on the polyamide resin. Can not.

In the present invention, the proportion of (c) a metal compound of a polyamide resin composition is Ru 1-10 wt% der the total of the polymer component in the composition (c) a metal compound (claim 1).
In the prior application, the content of the metal compound in the polyamide resin composition is 1 to 15% by weight based on the total of the polymer component and the metal compound. In the present invention, the metal compound is previously added to the polyamide resin. It is possible to obtain a good additive effect with a relatively small amount of the metal compound compared to the prior application by improving the effect of adding the metal compound to the polyamide resin by performing the two-stage kneading of the polyolefin elastomer after the kneading of it can. Thus, in the present invention, the durability can be further improved by reducing the blending amount of the metal compound in this way. That is, the metal compound blended in the resin composition can be a starting point of destruction when poor dispersion occurs in the composition. From that point of view, the blending amount is as much as possible within the range where the addition effect can be obtained. It is desirable to reduce
According to the present invention, by improving the kneading process at the time of manufacture, the addition effect can be reliably exhibited with a small amount of the metal compound, and the durability can be improved.

In the present invention, hydrotalcite is preferably used as the metal compound (c) (Claim 2 ).

The content of the polyolefin-based elastomer of the polyamide resin composition to be 10 to 45 wt% blend, flexibility, preferred in terms of durability (claim 3).

At least a portion as the polyolefin elastomer is a Rukoto been acid-modified to improve compatibility with the polyamide resin (claim 1).

The polyamide resin composition of the present invention is produced by such a method for producing the polyamide resin composition of the present invention, and is particularly suitable for forming a gas barrier layer of a refrigerant transport hose because of its excellent gas barrier properties and durability. It is suitable as a resin composition (claims 4 , 5 ).

The refrigerant transport hose of the present invention has such a gas barrier layer made of the polyamide resin composition of the present invention, and there is almost no problem with deterioration of the gas barrier layer due to the refrigerant or compressor oil, and durability performance is improved. Excellent (claim 6 ).

The refrigerant transporting hose of the present invention, particularly the outer peripheral side of such a gas barrier layer, it is preferable that the reinforcing layer and the external rubber layer is provided consisting of reinforcing thread (Claim 7).

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

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

[Polyamide resin composition and production method thereof]
First, the manufacturing method of the polyamide resin composition of this invention and the polyamide resin composition of this invention manufactured by this manufacturing method of a polyamide resin composition are demonstrated.

  The method for producing a polyamide resin composition of the present invention comprises (a) a polyamide resin, (b) a polyolefin-based elastomer, and (c) a divalent or trivalent metal hydroxide, oxide, and carbonate. In producing a polyamide resin composition containing one or more metal compounds selected from: (c) a metal compound and (a) a polyamide resin are first kneaded, and then the obtained kneaded product is (B) A polyolefin elastomer is kneaded.

<(A) Polyamide resin>
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.

<(B) Polyolefin elastomer>
The polyamide resin composition of the present invention contains a polyolefin-based elastomer. By containing 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.

  Polyolefin-based elastomers, especially those modified with acid anhydrides such as maleic anhydride, alkyl acrylate esters such as glycidyl methacrylate, epoxies, and modified products thereof, have a fine alloy structure based on polyamide resin. It can be obtained and is preferable.

  If the polyolefin 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 polyolefin elastomer cannot be sufficiently obtained, and if too large, the gas barrier property Therefore, the content in the polyamide resin composition is preferably 10 to 45% by weight, particularly preferably 20 to 40% by weight. If the content of the polyolefin-based elastomer 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 polyolefin-based elastomer, an effect that less specific energy and a high kneading technique are not required at the time of kneading (dispersing) can be obtained. In the case of using a modified elastomer as the polyolefin-based elastomer, the content of the modified elastomer in the polyamide resin composition is 20% by weight or less, for example, It is preferable to set it as 5 to 20 weight%.
In particular, in the present invention, it is preferable that 40 to 100% by weight of the polyolefin elastomer in the polyamide resin composition is an acid-modified elastomer.

In order to make the polyamide resin composition and the polyolefin elastomer compatible with each other, 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 to obtain a good dispersion form. Therefore, it is preferable that the average acid value (acid modification rate) of the whole elastomer used is 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 the polyolefin-based elastomer with the polyamide resin composition, the flexibility and durability are improved, but the gas barrier property is inevitably lowered. 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.

<(C) Metal compound>
The metal compound contained in the polyamide resin composition of the present invention is selected from divalent or trivalent metal hydroxides, oxides, and carbonates.
Here, examples of the divalent or trivalent metal include divalent metals such as magnesium, iron, zinc, calcium, nickel, cobalt, and copper, and trivalent metals such as aluminum, iron, and manganese.
Specific examples of hydroxides, oxides and carbonates of these metals include hydrotalcite, magnesium oxide, magnesium hydroxide, aluminum hydroxide, calcium oxide, and calcium carbonate. Hydrotalcite is preferred because it is considered to have an acid accepting effect.
These metal compounds may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Hydrotalcite is a kind of naturally occurring viscous mineral, and is a double hydroxide represented by the following general formula (I).
M ¹ _8-x M ² _x (OH) ₁₆ CO ₂ .nH ₂ O (I)

In formula (I), M ¹ is Mg ²⁺ , Fe ²⁺ , Zn ²⁺ , Ca ²⁺ , Li ²⁺ , Ni ²⁺ , Co ²⁺ , Cu ^2+, etc., M ² is Al ³⁺ , Fe ³⁺ , Mn ^3+, etc. ≦ x ≦ 2 and n ≧ 0.

As hydrotalcite, in the form containing crystal water, for example, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ , Mg ₄ Al ₂ (OH) ₁₂ CO ₃ .3.5H ₂ O, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O, Mg ₃ Al ₂ (OH) ₁₀ CO _{3 · 1.7H 2 O, Mg 3 ZnAl} 2 (OH) 12 CO 3 · wH 2 O, Mg 3 ZnAl 2 (OH) 12 CO 3 and the like. Examples of commercially available hydrous hydrotalcite include “DHT-4A” and “DHT-6” manufactured by Kyowa Chemical Industry Co., Ltd.

If the content of the metal compound in the polyamide resin composition is too small, the deterioration prevention effect due to the compounding of the metal compound cannot be sufficiently obtained, and if it is too much, an effect commensurate with the compounding amount cannot be obtained. However, as described above, when a dispersion failure occurs, it is not preferable because it becomes a starting point of destruction and rather deteriorates durability and further deteriorates properties such as gas barrier properties, flexibility, and aging resistance. Therefore, the content of the polyamide resin composition of the metal compound is based on the combined total of the polymer component of the metal compound and the polyamide resin composition of 1 to 10 wt%, good Mashiku is 1 to 5 wt%. As described above, since a sufficient addition effect can be obtained by blending a relatively small amount of the metal compound, the durability can be further improved in the present invention.

  Here, the polymer component in the polyamide resin composition refers to the total of polymer components such as (a) polyamide resin, (b) polyolefin-based elastomer, and other resins to be blended as necessary. .

<Other ingredients>
The polyamide resin composition of 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 a polyamide resin. It is preferable to ensure gas barrier properties.

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

  Further, the polyamide resin composition of 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 resistance agent, and a light resistance agent. Etc. can also be added.

<Manufacturing method of polyamide resin composition>
As described above, in the present invention, in the production of the polyamide resin composition, (a) a polyamide resin and (c) a metal compound are first kneaded, and (b) a polyolefin-based elastomer is kneaded into the obtained kneaded product. To perform a two-stage kneading to make a polymer alloy.

In the kneading of the polyamide resin and the metal compound, the metal compound is added to the polyamide resin, and the mixture is heated and kneaded at a temperature equal to or higher than the melting point of the polyamide resin, for example, about 10 to 60 ° C. higher than the melting point. Kneading step).
The kneading is not particularly limited as long as the metal compound is sufficiently uniformly dispersed in the polyamide resin.

  Next, a polyolefin-based elastomer is added to the kneaded product obtained by kneading the polyamide resin and the metal compound and kneaded (second kneading step). This kneading can be performed under the same conditions as in the first kneading step.

  In the present invention, in the first kneading step, only a part of the polyamide resin used for the production of the composition can be kneaded, and the remaining part can be kneaded in the second kneading step. From the viewpoint of uniformly dispersing as many metal compounds as possible in the polyamide resin phase therein, it is preferable to knead 70% by weight or more, preferably the entire amount, of the polyamide resin used in the first kneading step. For the same reason, it is preferable not to add the polyolefin-based elastomer in the first kneading step, but to add and knead the whole amount of the polyolefin-based elastomer used for producing the composition in the second kneading step.

  In addition, even when the above-mentioned other components to be blended in the polyamide resin composition are blended as necessary, the uniform dispersibility of the metal compound in the polyamide resin phase by kneading the polyamide resin and the metal compound in advance. In order to further enhance the improvement effect, other components are preferably added and kneaded in the second kneading step of kneading the polyolefin elastomer.

  It is also possible to knead the polyamide resin and the metal compound in advance to make a master batch, and knead the polyolefin elastomer in this master batch. However, the polyolefin elastomer is added following the kneading of the polyamide resin and the metal compound. It is efficient to knead.

[Hose for refrigerant transport]
Next, the refrigerant transport hose of the present invention using the polyamide resin composition of the present invention produced by the production method of the present invention as a constituent material of the gas barrier layer will be described with reference to the drawings.

  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 the gas barrier layer 2 made of the above-described polyamide resin composition of the present invention, and an inner rubber layer 3 is formed on the outer periphery thereof. Hereinafter, the first reinforcing yarn layer 4 is sequentially formed. The intermediate rubber layer 5, the second reinforcing yarn layer 6, and the outer 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, the material of each layer will be described.

<Gas barrier layer>
The gas barrier layer 2 is made of the polyamide resin composition of the present invention.

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.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Examples 1 to 4, Comparative Examples 1 to 5]
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 kneading was performed at 230 ° C., which is a temperature equal to or higher than the melting point (220 ° C.) of the polyamide resin.

  The kneading is performed in two stages, and the polyamide resin and hydrotalcite are kneaded in the first stage, and the polyamide resin and elastomer kneaded in the second stage are kneaded (two-stage kneading: Examples 1 to 4). ).

  For comparison, one using only a polyamide resin (Comparative Example 5), and one obtained by kneading a polyamide resin and an elastomer in advance to form a polymer alloy and then adding and kneading hydrotalcite (post-addition: Comparative Examples 1 to 2) Similarly for 4), a test polyamide resin piece was produced.

  The materials used for the production of the test polyamide resin pieces are as follows.

Polyamide resin: 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”
Hydrotalcite: “Hydrotalcite DHT-4A” manufactured by Kyowa Chemical Co., Ltd.
Composition formula: Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O

  About the obtained polyamide-type resin piece for a test, the characteristic evaluation was performed by the following method and the result was shown in Table 1.

<Dispersibility>
Using an electron microscope (SEM), observe the test polyamide resin piece surface-treated with phosphotungstic acid to examine the dispersed particle size of the elastomer. If the elastomer dispersed particle size is 3 μm or less, OK is greater than 3 μm. It was.

<4% elongation elastic modulus index>
Using a tensile tester manufactured by Toyo Seiki Co., Ltd., each test polyamide resin piece was stretched at a pulling speed of 50 mm / min to measure the modulus of elasticity, and an index relative to the test polyamide resin piece (100) of Comparative Example 5 was used. Indicated.

<Gas permeability index>
Using a gas permeation tester manufactured by GTR Tech, the He gas permeability coefficient was measured at 100 ° C. with an absolute differential pressure of 226 cmHg for each polyamide resin piece for testing, and an index for the polyamide resin piece for testing (100) in Comparative Example 5 The notation.

<Strong retention after aging>
Using a tensile tester manufactured by Toyo Seiki Co., Ltd., for each test polyamide resin piece before and after the aging test, the tensile strength was measured by stretching at a tensile speed of 50 mm / min, and after the aging test with respect to the value before the aging test Expressed as a percentage of the value.

<Elongation at break after aging>
Using a tensile tester manufactured by Toyo Seiki Co., Ltd., for each test polyamide resin piece before and after the following aging test, the elongation at break was measured at a tensile rate of 50 mm / min, and the rupture elongation was measured with respect to the value before the aging test. Expressed as a percentage of the value.

(Aging test)
The following procedures 1 to 7 were performed.
1 Put 1 cc of water in a pressure vessel.
2 Insert a test piece of polyamide-based resin 10 × width 10 × length 50 mm × thickness 0.1 mm.
3 Add 100 cc of polyalkylene glycol oil.
4 After freezing the pressure vessel for 15 minutes, vacuum the pressure vessel for 5 minutes.
5 Add 100 cc of R-134a as refrigerant.
6 Leave in a high temperature bath at 150 ° C for 8 weeks.
7. Remove the test polyamide resin piece from the container and use it for evaluation measurement.

  From Table 1, it can be seen that the polyamide resin composition obtained by kneading a metal compound with a polyamide resin in advance and then kneading a polyolefin-based elastomer can form a gas barrier layer excellent in gas barrier properties, flexibility, and durability. . In particular, from the comparison of Examples 1 to 4 and Comparative Examples 1 to 4 in which the blending composition is the same and only the kneading procedure is different, the blending amount of the metal compound necessary for improving the durability is reduced according to the present invention. You can see that you can.

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 (7)

One or more metal compounds selected from the group consisting of (a) a polyamide resin, (b) a polyolefin-based elastomer, and (c) a hydroxide, oxide, and carbonate of a divalent or trivalent metal. In a method for producing a polyamide resin composition comprising:
(C) a first kneading step of kneading the metal compound and (a) the polyamide resin;
A kneaded product obtained in the first kneading step and (b) a second kneading step of kneading the polyolefin-based elastomer, and a method for producing a polyamide resin composition,
The ratio of (c) metal compound to the total of the polymer component and (c) metal compound in the polyamide resin composition is 1 to 10% by weight,
A method for producing a polyamide resin composition, wherein at least a part of the polyolefin-based elastomer is acid-modified . Oite to claim 1, method for producing a polyamide resin composition, wherein the (c) metal compound is hydrotalcite. The method for producing a polyamide resin composition according to claim 1 or 2 , 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. The polyamide resin composition manufactured by the manufacturing method of the polyamide resin composition of any one of Claim 1 thru | or 3 . The polyamide resin composition according to claim 4 , which is a polyamide resin composition for forming a gas barrier layer of a refrigerant transport hose. A refrigerant transport hose having a gas barrier layer made of a polyamide resin composition, wherein the polyamide resin composition is the polyamide resin composition according to claim 4 or 5 . The refrigerant transport hose according to claim 6 , wherein a reinforcing layer made of a reinforcing yarn and an outer rubber layer are provided on an outer peripheral side of the gas barrier layer.

Images