JP2013228081A - Air conditioner hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner hose excellent in a refrigerant barrier property with respect to a new refrigerant and excellent in a water permeable barrier property.SOLUTION: An air conditioner hose includes a tubular innermost layer 1 for circulating a new fluorine refrigerant. The innermost layer 1 is composed of a rubber composition which is mainly composed of the following (A) and (B) and contains the following (C): (A) butyl rubber, (B) acrylonitrile-butadiene copolymer rubber in which content of acrylonitrile is 40 wt.% or more, and (C) a scale filler. An outer periphery of the innermost layer 1 includes a low water permeable layer 3.

Description

  The present invention relates to an air conditioner hose excellent in refrigerant barrier properties against a next-generation fluorine-based new refrigerant (hereinafter sometimes simply referred to as “new refrigerant”).

Currently, R134a refrigerant (CF ₃ CH ₂ F) is widely used as a refrigerant for car air conditioners. Since the refrigerant transport hose using the R134a refrigerant is excellent in the refrigerant barrier property, an air conditioner hose using a rubber composition mainly composed of butyl rubber as the innermost layer has been proposed (for example, Patent Document 1). ).

JP 2004-176908 A

  By the way, in recent years, introduction of refrigerants having a low global warming potential (GWP) has been studied in various countries around the world as part of global environmental measures. The conventional R134a refrigerant had a high GWP of 1430, but HFO-1234yf (2,3,3,3-tetrafluoro-1-propene) (GWP: 4) was developed as a new low GWP fluorine refrigerant. Practical use is progressing. However, the air conditioner hose described in Patent Document 1 has an excellent refrigerant barrier property with respect to the conventional R134a refrigerant, but is insufficient in the refrigerant barrier property with respect to new refrigerants such as HFO-1234yf. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an air conditioner hose that is excellent in refrigerant barrier properties against a new refrigerant and also excellent in water permeability barrier properties.

  In order to obtain an air conditioner hose that has excellent refrigerant barrier properties against new refrigerants and excellent water permeability barrier properties, the present inventors first focused on the solubility parameter (SP value) of the new refrigerant and butyl rubber. Repeated research. The SP value of the conventional R134a refrigerant is 14, whereas the SP value of the new refrigerant HFO-1234yf is 6, so the SP value of butyl rubber used for the innermost layer of the air conditioner hose (7.7-8) The difference from 1) becomes large. For this reason, the refrigerant molecules of the new refrigerant are dissolved in the innermost layer and easily diffused, and it has been found that the refrigerant barrier property against the new refrigerant is inferior. As a result of repeated experiments, a rubber composition comprising a butyl rubber blended with an acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 40% by weight or more, and a flaky filler such as talc. It has been found that when an object is used in the innermost layer of an air conditioner hose, it has excellent refrigerant barrier properties against a new refrigerant, and the present invention has been achieved. The reason for this is not clear, but since the SP value of a specific acrylonitrile-butadiene copolymer rubber is higher than the SP value of a butyl rubber, blending a specific acrylonitrile-butadiene copolymer rubber with a butyl rubber, The SP value of the blend rubber is higher than that of the butyl rubber alone, and the difference between the SP value of the blend rubber and the SP value of the new refrigerant HFO-1234yf (SP value: 6) is increased. Therefore, the refrigerant molecules of the new refrigerant are difficult to dissolve in the innermost layer, or even if dissolved, the above specific acrylonitrile-butadiene copolymer rubber is difficult to diffuse, and as a result, the refrigerant barrier property against the new refrigerant is improved. It is assumed that

That is, the air-conditioning hose of the present invention is an air-conditioning hose provided with a tubular innermost layer for circulating a new fluorine-based refrigerant, the innermost layer having the following (A) and (B) as main components, It consists of the rubber composition containing (C), and takes the structure of providing the low water-permeable layer in the outer periphery of the said innermost layer.
(A) Butyl rubber.
(B) An acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 40% by weight or more.
(C) Scale-like filler.

  As described above, in the air conditioner hose of the present invention, the innermost layer is blended with the butyl rubber (A) because the acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 40% by weight or more is blended. And the SP value of the blend rubber and the SP value of the new refrigerant HFO-1234yf (SP value: 6) are increased. Therefore, the refrigerant molecules of the new refrigerant are difficult to dissolve in the innermost layer, or even if dissolved, the above specific acrylonitrile-butadiene copolymer rubber is difficult to diffuse, and as a result, the refrigerant barrier property against the new refrigerant is improved. To do. Further, since a low water permeable layer such as butyl rubber is formed on the outer periphery of the innermost layer, water can be prevented from entering from the outside of the system, and the water permeable barrier property is excellent.

  Further, when the weight mixing ratio of (A) and (B) is (A) / (B) = 90/10 to 5/95, the refrigerant barrier property is good.

  Further, when the scale-like filler (C) is at least one selected from the group consisting of talc, mica, sericite, montmorillonite, silica and clay, the refrigerant barrier property is further improved.

  And refrigerant | coolant barrier property becomes favorable in content of the said scale-like filler (C) being 15-200 weight part with respect to a total of 100 weight part of (A) and (B).

It is a block diagram which shows an example of the air-conditioner hose of this invention.

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

  As the air-con hose of the present invention, for example, as shown in FIG. 1, there is a configuration in which an outer layer (low water permeable layer) 3 is formed on the outer peripheral surface of a tubular innermost layer 1 via a reinforcing layer 2.

In the present invention, the greatest feature is that the innermost layer 1 is composed of a rubber composition containing the following (A) and (B) as main components and the following (C).
(A) Butyl rubber.
(B) An acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 40% by weight or more.
(C) Scale-like filler.

In the present invention, the new fluorine-based refrigerant has a lower GWP than the conventional fluorine-based refrigerant R134a refrigerant (GWP: 1430) and has a double bond in the molecular structural formula and is easily decomposed in the atmosphere. A refrigerant is preferable, and specifically, an HFO-1234yf refrigerant (CF ₃ CF═CH ₂ ) (GWP: 4) can be given.

  In the present invention, the main component means a main component in the rubber composition, and usually means a component that occupies a majority of the entire rubber composition.

[Innermost layer 1]
First, the rubber composition forming the innermost layer 1 of the air conditioner hose of the present invention will be described.

<< Butyl rubber (A) >>
Examples of the butyl rubber (A) include butyl rubber (IIR) and halogenated butyl rubber, which may be used alone or in combination of two or more. Examples of the halogenated butyl rubber include chlorinated butyl rubber (Cl-IIR) and brominated butyl rubber (Br-IIR).

<< Specific acrylonitrile-butadiene copolymer rubber (B) >>
As the specific acrylonitrile-butadiene copolymer rubber (B), those having an acrylonitrile content (hereinafter sometimes referred to as “nitrile amount” or “AN amount”) of 40% by weight or more are preferably used. An acrylonitrile-butadiene copolymer rubber having a nitrile amount of 50% by weight or more is used. This is because if the amount of nitrile is too low, the refrigerant barrier property is inferior. If the amount of nitrile is too high, the viscosity of the acrylonitrile-butadiene copolymer rubber becomes high and kneading workability becomes difficult, so the upper limit is preferably 60% by weight or less.

  Examples of the acrylonitrile-butadiene copolymer rubber (B) include acrylonitrile-butadiene copolymer rubber (NBR) alone or a blend rubber (NBR-PVC) of NBR and vinyl chloride (PVC). These may be used alone or in combination of two or more.

  As the NBR grade, for example, extremely high AN (AN amount: 50%) is used.

  Examples of the NBR include hydrogenated NBR (H-NBR) and modified NBR (such as carboxyl-modified NBR) in addition to NBR. These may be used alone or in combination of two or more.

  The blend ratio (weight ratio) of NBR and PVC in the NBR-PVC is preferably in the range of NBR / PVC = 90 / 10-50 / 50, particularly preferably in the range of NBR / PVC = 90 / 10-60 / 40. is there.

  In the present invention, the weight mixing ratio of (A) and (B) is preferably (A) / (B) = 90/10 to 5/95, particularly preferably (A) / (B) = 90 / 10-70 / 30. When the amount of (B) is too small [the amount of (A) is too large], the effect of improving the refrigerant barrier property tends to be reduced, and when the amount of (B) is too large [the amount of (A) is too small], the water permeability deteriorates. There is a tendency to

<< Scaly filler (C) >>
Examples of the scale-like filler (C) include talc, mica, sericite, montmorillonite, silica, clay and the like. These may be used alone or in combination of two or more. Among these, talc is preferable in that the refrigerant barrier property is improved.

  The average diameter of the scaly filler (C) is usually 0.1 to 700 μm, preferably 1 to 100 μm. The scale-like filler (C) preferably has an aspect ratio defined by (average diameter / thickness) of 2 to 90, particularly preferably 15 to 70. If the aspect ratio of the flaky filler (C) is too small, the orientation of the flaky filler (C) tends to be small, and the shielding property against gas molecules tends to be small, so that it is difficult to obtain sufficient refrigerant barrier properties. When the aspect ratio is too large, the kneading dispersibility becomes low and it becomes difficult to uniformly disperse, and the moldability tends to be lowered.

  The content of the scaly filler (C) is preferably 15 to 200 parts by weight, particularly preferably 50 to 180 parts by weight, based on 100 parts by weight of the total of (A) and (B). If the content of the scale-like filler (C) is too small, the refrigerant barrier property tends to be lowered, and if the content of the scale-like filler (C) is too high, it becomes too hard and the flexibility of the hose The vibration absorbability is inferior, and the extrudability tends to deteriorate.

  The rubber composition used in the present invention includes a vulcanizing agent (D) in addition to the butyl rubber (A), the specific acrylonitrile-butadiene copolymer rubber (B), and the scaly filler (C). Carbon black, plasticizer, etc. may be blended.

<< Vulcanizing agent (D) >>
Examples of the vulcanizing agent (D) include a resin vulcanizing agent and sulfur. These may be used alone or in combination of two or more. A resin vulcanizing agent is preferable because it is excellent in co-crosslinking property with the acrylonitrile-butadiene copolymer rubber (B).

  Examples of the resin vulcanizing agent include alkylphenol resins and modified alkylphenol resins.

  The content of the vulcanizing agent (D) is preferably 5 to 20 parts by weight, particularly preferably 7 to 12 parts by weight, based on 100 parts by weight of the total of (A) and (B).

  The carbon black content can be adjusted according to the desired tensile properties and hardness, but is preferably 20 to 150 parts by weight with respect to the total of 100 parts by weight of the above (A) and (B). Preferably it is 40-100 weight part.

  Examples of the plasticizer include aroma oil, naphthenic oil, paraffin oil and the like. These may be used alone or in combination of two or more.

  The content of the plasticizer is preferably 10 parts by weight or less, particularly preferably 5 parts by weight or less, based on 100 parts by weight of the total of (A) and (B).

  In addition to the butyl rubber (A), the specific acrylonitrile-butadiene copolymer rubber (B), and the scaly filler (C), the rubber composition used in the present invention may contain a vulcanizing agent (D ) And the like, and these can be prepared by kneading them using a Banbury mixer, open roll, kneader or the like.

[Reinforcing layer 2]
As a material for forming the reinforcing layer 2, for example, a reinforcing wire such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyamide, vinylon, rayon, metal wire or the like can be used.

  The reinforcing layer 2 can be produced by braiding the reinforcing wire such as the PET yarn with a blade braid, a spiral braid, a knit braid or the like.

[Outer layer (low water permeable layer) 3]
Examples of the material for the low water permeable layer forming the low water permeable layer 3 include rubber, resin, metal film (metal foil), and the like. Among these, rubber is preferable from the viewpoint of excellent water permeability barrier properties.

  Examples of the rubber include butyl rubber [butyl rubber, halogenated butyl rubber (1-IIR, Br-IIR, etc.)], chloroprene rubber (CR), hydrin rubber (CO, ECO), and the like. These may be used alone or in combination of two or more. Among these, butyl rubber is preferable in terms of excellent water permeability barrier properties.

  In addition to the rubber as the main component, the low water-permeable layer material may be blended with additives or the like that are usually blended in rubber compositions.

  As said resin, resin with high water resistance is preferable, for example, polyolefin resin etc. are mention | raise | lifted.

  Examples of the metal film (metal foil) include aluminum and copper.

  The air conditioner hose of the present invention has the innermost layer made of a rubber composition containing the above (A) to (C), and has a structure having a low water permeable layer on the outer periphery of the innermost layer, as shown in FIG. It is not limited to the layer structure (innermost layer / reinforcing layer / outer layer), and may have a structure of two layers or four layers or more. In the air conditioner hose of the present invention, for example, the innermost layer may have a two-layer structure of an inner surface layer and an outer surface layer [innermost layer (inner surface layer / outer surface layer) / reinforcing layer / outer layer]. However, the said inner surface layer needs to consist of a rubber composition containing said (A)-(C).

  In the air conditioner hose of the present invention, as a material (non-low water-permeable layer material) other than the low water-permeable layer (non-low water-permeable layer material), for example, ethylene-propylene copolymer (EPM), ethylene-propylene- Diene terpolymer (EPDM), chloroprene rubber (CR), fluorine rubber (FKM), epichlorohydrin rubber (ECO), acrylic rubber, and the like can be used.

  In addition to the rubber (EPM, EPDM, etc.) as a main component, the non-low water-permeable layer material may be blended with additives or the like that are usually blended in rubber compositions.

  Below, the manufacturing method of the air-conditioner hose of this invention is demonstrated. That is, first, a rubber composition (material for the innermost layer) containing the above (A) to (C) as essential components is prepared. The rubber composition is extruded on a mandrel to form the innermost layer 1, and then a reinforcing yarn is braided on the surface of the rubber composition to form the reinforcing layer 2. Next, after the low water-permeable layer material is extruded on the outer peripheral surface of the reinforcing layer 2 to form the outer layer (low water-permeable layer) 3, these are vulcanized under predetermined conditions. Thereafter, the mandrel is extracted, and an air conditioner hose (see FIG. 1) in which the reinforcing layer 2 and the outer layer 3 are sequentially formed on the outer peripheral surface of the innermost layer 1 can be produced.

  The air conditioner hose of the present invention is not limited to the above manufacturing method. For example, the reinforcing layer 2 may be formed by braiding reinforcing yarn directly on the surface of the innermost layer 1 without using a mandrel. Good. Further, a bellows portion may be formed at the center of the hose.

  The air conditioner hose of the present invention has an inner diameter of usually 5 to 50 mm, preferably 6 to 33 mm. The innermost layer 1 has a thickness of usually 0.5 to 4 mm, preferably 1 to 3 mm, and the outer layer 3 has a thickness of usually 0.5 to 5 mm, preferably 1 to 4 mm.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” mean weight basis.

  First, prior to Examples and Comparative Examples, the following innermost layer materials were prepared.

<< Butyl rubber (A) >>
[Chlorinated butyl rubber (Cl-IIR) (A1)]
Butyl HT1066, manufactured by JSR

<< Specific acrylonitrile-butadiene copolymer rubber (B) >>
[NBR (B1)]
Nipol DN003 manufactured by ZEON Corporation (AN amount: 50%)
[NBR (B2)]
Nipol 1041 manufactured by Zeon Corporation (AN amount: 40.5%)
[NBR-PVC (B3)]
Nipol DN517SCR manufactured by ZEON Corporation (AN amount: 43%)

[NBR (B'1)]
Nipol DN219 manufactured by Zeon Corporation (AN amount: 33.5%)
[NBR (B'2)]
Nipol DN401 (AN amount: 18%) manufactured by Nippon Zeon

<< Scaly filler (C) >>
[Talc (C1)]
Mistrone vapor talc (average particle size: 5.7 to 6.5 μm), manufactured by Nippon Mytron

<< Vulcanizing agent (D) >>
[Resin vulcanizing agent (D1)]
Reactive alkylphenol / formaldehyde resin (Taoka Chemical Co., Ltd., Tactrol 201)

[Preparation of rubber composition (material for innermost layer)]
The components shown in Table 1 below were blended in the proportions shown in the same table, and these were kneaded using a Banbury mixer to prepare a rubber composition.

[Preparation of low water-permeable layer material (Cl-IIR)]
To 100 parts of chlorinated butyl rubber (Cl-IIR) (JSR, Butyl HT1066), 1 part of stearic acid (Kao Corporation, Lunac S-30), 40 parts of carbon black (Tokai Carbon Co., Seast 116), , 110 parts of talc (manufactured by Nippon Talc Co., Ltd., Microace K-1), 5 parts of zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., 2 types of zinc oxide), reactive alkylphenol-formaldehyde resin (manufactured by Taoka Chemical Industry Co., Ltd., tackolol) ) 10 parts was blended and kneaded using a Banbury mixer to prepare a low water permeable layer material (Cl-IIR).

[Preparation of non-low-permeable material (EPDM)]
EPDM (Sumitomo Chemical Co., Esprene 532) 100 parts, zinc oxide (Sakai Chemical Industry Co., Ltd., 2 types of zinc oxide) 5 parts, stearic acid (Kao Co., Ltd., LUNAC S30) 1 part, carbon black (Showa 100 parts of Cabot, Show Black IP200), 40 parts of a filler (Mistron Paper Talc, manufactured by Nippon Mystron), 60 parts of oil (Diana Process PW-380, manufactured by Idemitsu Kosan Co., Ltd.) Used for mastication [5 minutes mastication (final temperature 180 ° C.)]. Next, this was transferred to an open roll, and 4 parts of a vulcanization accelerator (manufactured by Sanshin Chemical Co., Ltd., Sunseller TT) and 1 part of sulfur (manufactured by Daito Sangyo Co., Ltd., sulfur-PTC) were added and mixed for 2 minutes. Kneading was performed to prepare a material for non-low water-permeable layer (EPDM).

[Example 1]

  The rubber composition A prepared above (see Table 1) was extruded on a mandrel to form an innermost layer, and then a PET yarn was braided onto the surface to form a reinforcing layer. Next, after forming the outer layer (low water permeable layer) by extruding the low water permeable layer material (Cl-IIR) on the outer peripheral surface of the reinforcing layer, these were vulcanized (150 ° C. × 60 minutes). , Extracted the mandrel. In this manner, an air conditioner hose (inner diameter: 16 mm) in which a reinforcing layer and an outer layer (thickness 1 mm) were sequentially formed on the outer peripheral surface of the innermost layer (thickness 2 mm) was produced.

[Examples 2 to 5]
An air conditioner hose was produced in the same manner as in Example 1 except that the rubber composition (see Table 1) as the innermost layer material was changed to the rubber composition of the type shown in Table 2 below.

Example 6
The innermost layer has a two-layer structure of an inner surface layer and an outer surface layer, rubber composition A (see Table 1) is used for the inner layer material, and a low water permeable layer material (Cl-IIR) is used for the outer layer material. At the same time, the material of the outer layer was changed to the previously prepared material for non-low water permeable layer (EPDM). That is, the inner surface layer material (rubber composition A) and the outer surface layer material [low water permeable layer material (Cl-IIR)] are simultaneously extruded to form an inner surface layer (thickness 1 mm) and an outer surface layer (thickness 1 mm). An air conditioner hose was produced according to Example 1 except that the innermost layer had a two-layer structure and the outer layer (non-low water-permeable layer) was formed by extruding the material for non-low water-permeable layer (EPDM). .

[Comparative Examples 1-4]
The rubber composition (see Table 1), which is the innermost layer material, is changed to the rubber composition of the type shown in Table 2 below, and the outer layer material is changed to the previously prepared non-low water permeable layer material (EPDM). An air conditioner hose was manufactured in the same manner as in Example 1 except that the change was made.

  Using the example product and the comparative product thus obtained, each characteristic was evaluated according to the following criteria. The results are also shown in Table 2 above.

(Refrigerant barrier properties)
A rubber sheet having the same laminated structure as the layer structure of each hose was produced, and gas permeability was evaluated using this rubber sheet. That is, after closing the opening of the cup filled with Freon gas (HFO-1234yf) at low temperature (−35 ° C. or less) with a vulcanized rubber sheet, it was left in an oven at 90 ° C. The change (weight loss) of freon gas per day was determined as the freon gas permeation amount. And it showed by the relative index | exponent by making the freon gas permeation amount of the comparative example 3 goods into a reference | standard (100). If this relative index is smaller than 100, it indicates that the refrigerant barrier property is good. In the evaluation, those having a relative index smaller than 100 were evaluated as ◯, and those having a relative index of 100 or more as ×.

[Permeability barrier]
A rubber sheet having the same laminated structure as the layer structure of each hose was produced, and moisture permeability was evaluated using this rubber sheet. That is, the opening of a cup filled with water at normal temperature (23 ° C.) is closed with a vulcanized rubber sheet, and then left in an oven at 80 ° C. to change the weight of water per day relative to the permeation area. (Weight loss) was determined as the amount of moisture permeation. And it showed by the relative index | exponent by making the water permeation amount of the comparative example 3 goods into the reference | standard (100). If this relative index is 100 or less, it indicates that the water permeability barrier property is good. In the evaluation, those having a relative index of 100 or less were evaluated as ○, and those exceeding 100 were evaluated as ×.

  From the results of Table 2 above, the example products were good in both refrigerant barrier properties and water permeability barrier properties.

On the other hand, NBR (B′1, B′2) having a small AN amount is used for the innermost layers of the first and second comparative examples, and therefore the refrigerant barrier property is inferior.
Since only the butyl rubber (A) was used for the innermost layer of Comparative Example 3 and no specific acrylonitrile-butadiene copolymer rubber (B) was used in combination, the refrigerant barrier property was inferior.
Since Comparative Examples 1, 2, and 4 did not have a low water permeable layer on the outer periphery of the innermost layer, the water permeable barrier property was inferior.

  The air conditioner hose for a new fluorine-based refrigerant of the present invention is excellent in refrigerant barrier properties against the next-generation fluorine-based new refrigerant (particularly HFO-1234yf refrigerant).

1 innermost layer 2 reinforcing layer 3 outer layer (low water permeable layer)

Claims (9)

An air conditioner hose having a tubular innermost layer for circulating a new fluorine-based refrigerant, wherein the innermost layer is composed mainly of the following (A) and (B), and contains the following (C): An air conditioner hose comprising a low water-permeable layer on the outer periphery of the innermost layer.
(A) Butyl rubber.
(B) An acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 40% by weight or more.
(C) Scale-like filler.   The air conditioning hose according to claim 1, wherein a weight mixing ratio of (A) and (B) is (A) / (B) = 90/10 to 5/95.   The air conditioner hose according to claim 1 or 2, wherein (C) is at least one selected from the group consisting of talc, mica, sericite, montmorillonite, silica and clay.   The air conditioner hose according to any one of claims 1 to 3, wherein the content of (C) is 15 to 200 parts by weight with respect to a total of 100 parts by weight of (A) and (B). The air conditioning hose according to any one of claims 1 to 4, wherein the rubber composition further contains (D) below in addition to (A) to (C).
(D) Vulcanizing agent.   6. The air conditioner hose according to claim 5, wherein (D) is a resin vulcanizing agent.   The air conditioning hose according to claim 5 or 6, wherein the content of (D) is 5 to 20 parts by weight with respect to a total of 100 parts by weight of (A) and (B).   The air conditioner hose according to any one of claims 1 to 7, wherein the new fluorine-based refrigerant is an HFO-1234yf refrigerant.   The air conditioner according to any one of claims 1 to 8, wherein the acrylonitrile-butadiene copolymer rubber (B) is an acrylonitrile-butadiene copolymer rubber or a blend rubber of acrylonitrile-butadiene copolymer rubber and vinyl chloride. hose.

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