JPS6182088A - Hose for fluorohydrocarbon group refrigerant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a fluorohydrocarbon refrigerant hose
L is particularly suitable for piping with many bends in car coolers, air conditioners, etc. of automobiles.

<Prior art> Conventionally, the above-mentioned type of refrigerant hose has, for example, an NBR inner tube 1 and a polyester fiber reinforced layer 2, as shown in FIG.
Many of the tubes were made of rubber and consisted of an outer tube 3 made of EPDM. In the case of this rubber hose, the flexibility is good, but rubber has high permeability to fluorohydrocarbon refrigerants (hereinafter simply referred to as "refrigerant"), so the amount of refrigerant permeation is large. Therefore, the walls (especially the inner tube) are made thicker, but the amount of refrigerant permeation cannot be reduced compared to the increased weight (see Table 1).Therefore, instead of the rubber one, a three-layer structure, Those with an inner tube 1 made of nylon, a polyester fiber reinforcing layer 2, and an outer tube 3 made of polyolefin elastomer are on the market. In the case of this resin hose, the amount of refrigerant permeation can be reduced because nylon, which has low refrigerant permeability, is used for the inner tube, but due to the rigidity and moisture absorption of nylon, the amount of water permeation increases and becomes flexible. Problems also arise. In other words, the former reduces the cooling capacity of the compressor! x1! +! The latter is subject to piping design limitations.

Therefore, as shown in FIG.
It has been proposed that the system consists of
(See the microfilm copy of the specification etc. attached to No. 916).

<Problems to be Solved by the Invention> However, in the case of the above-mentioned resin hose, although the problem of water permeation can be solved, it does not have sufficient flexibility, and the resin hose is roughly composed of nylon (inner tube inner layer) and polyethylene (inner tube outer layer). ) causes problems in terms of interlayer adhesion.

Means for Solving the Problems> This invention forms the inner layer of the inner tube with nylon having low refrigerant permeability to a thickness of 0.1 to 0.51, and the inner layer adjacent to the outside of the inner layer of the inner tube. The outer tube layer or the inner tube middle layer has a bending elastic modulus of 1
Polyolefin content 4 below 500 kg/crn'
The above problem is solved by forming a wall thickness of 0.5 to 1.5 mm with 0 to 80 wt% of polyolefin modified nylon 11 or 12.Next, each of the above structures will be explained in detail. (See Figures 2-3).

(1) The nylon forming the inner tube inner layer 4 is as follows:
Examples include nylon 6, nylon 11, and nylon 12, which have low refrigerant permeability. Furthermore, if the wall thickness of the inner tube inner layer 4 is less than O.
If it exceeds 5mV, the bending stiffness increases and problems arise in terms of flexibility.

(2) The olefin-modified nylon 11 or 12 forming the inner tube outer layer 5 or the inner tube intermediate layer 5A which is in contact with the outside of the inner tube inner layer is as follows.

Nylon 11 or nylon 12 and PE, PP, PE-
It is obtained by blending or copolymerizing with a polyolefin such as a PP copolymer. For this blending, a polyolefin modified with maleic anhydride or the like is used (see Japanese Patent Publication No. 55-44108), and
Copolymerization is carried out using polymers with a molecular weight of 100 that have functional groups such as hydroxyl groups, carboxyl groups, epoxy groups, and incyanate groups at both ends.
Block copolymerization or graft copolymerization with nylon 11 or 12 is performed using a telechelic polyolefin having a molecular weight of 0 to 10,000. At this time, the blend,
Both copolymers have a polyolefin content of 40 wt%
If it is less than that, the water permeability and flexural modulus will be high,
If it exceeds 80 wt%, interlayer adhesion and coextrusion with the inner tube inner layer become difficult, which is undesirable.

If the thickness of the outer layer of the inner tube or the intermediate layer of the inner tube is less than 0.5 m+w, the amount of water permeation will increase, and if it exceeds 1.5+ am, the weight will increase, each of which causes problems. Moreover, if the bending elastic modulus exceeds 1500 kg/crrr', the bending stiffness increases, causing a problem in the flexibility of the hose.

(3) As shown in FIG. middle layer 5
A. When forming the outer layer 6, the outer layer is made of a soft polyolefin such as PE or PP that has low moisture permeability. In this case, since the intermediate layer is formed of polyolefin-modified nylon 11 or nylon 12, the problem of poor interlayer adhesion does not occur.

(4) The reinforcing layer 2 and the outer tube 3 located outside the inner tube l are
Same as before. That is, the reinforcing layer is made of synthetic fibers such as polyester (e.g. 4fPET), nylon, rayon, etc., and the outer tube is made of polyolefin, polyester, PVC, polyamide, etc., which have flexibility that does not inhibit the flexibility of the hose. Made of thermoplastic elastomer.

(5) These refrigerant hoses are manufactured by forming an inner tube (usually coextruded), a reinforcing layer, and an outer tube by conventional means using an extrusion molding machine and a braiding machine. It should be noted that the outer tube is not necessary since it serves to protect and buffer the hose.

<Examples> Hereinafter, the present invention will be described in more detail based on Examples.

The manufacturing method of each resin refrigerant hose of Comparative Examples 2 to 3 and Examples 1 to 2 was as follows:
After coextruding 1), polyester fiber (1500D/1
A reinforcing layer is formed by applying 24 braids and a braiding angle of 54°) onto the inner tube using a polyolefin-based elastomer. An outer tube was formed by covering the tube to a thickness of -41°2 ma+. In addition, the rubber refrigerant hose of Comparative Example 1 is as follows.

Inner tube: Made of NBR, wall thickness 3.3cm, Reinforcement layer: Polyester fiber braid, Outer tube: Made of EPDM, wall thickness 0.7rtrtt
It is r.

Tests were conducted on the following items for each refrigerant hose obtained as described above (however, the number of samples was n = 5) (a) Refrigerant permeation amount... According to the measurement method of JRA2001-1976 (Japan Air Conditioning Industry Association standard) I followed the instructions.

(b) Moisture permeation amount: Change in the weight of the desiccant after the desiccant is sealed in the hose and left in a constant temperature bath at 70°C x 95% RH for 72 hours with both ends of the hose closed. Obtained by measuring.

(c) Bending stiffness: Measured by cantilever method at room temperature of 20°C.

(d) Bending limit R: The hose was bent into a U-shape at a room temperature of 20° C., the R of the bent portion was gradually reduced, and the bending R immediately before kinging was determined.

(e) Weight: Each tree was measured using a stand.

<Effects of the Invention> As described above, in the refrigerant hose of the present invention, the inner tube inner layer is formed of nylon with a specific thickness, and the layer adjacent to the inner tube inner layer has a specific thickness and contains a specific amount of polyolefin. By forming it with modified nylon 11 or 12, the amount of Freon gas permeation and the amount of moisture permeation are small, and the problems of flexibility (low bending stiffness and small bending limit R) and interlayer adhesion are also solved. This is also clear from the test results in Table 1. Therefore, this refrigerant hose is suitable for use in cases where there are many bends, such as piping in automobile car coolers, air conditioners, and the like. In addition,
In the case of the first embodiment, which does not use PE having a low melting point, the heat resistance of the refrigerant hose is also improved.

Table 1 X...Insufficient, Δ...Slightly long, 0...
Slightly dull, ■...Good.

[Brief explanation of drawings]

The illustrated examples show each configuration of a refrigerant hose. Figure 1 is a cutaway perspective view of a single-layer inner tube, Figure 2 is a cutaway perspective view of a two-layer inner tube, and Figure 3 is a cutaway perspective view of a two-layer inner tube. It is a notch perspective view in case of a layer. l...Inner tube, 2...Reinforcement layer, 3...Outer tube, 4...
・Inner tube inner layer, 5... Inner tube outer layer (layer adjacent to the outside of the inner tube), 5A... Inner tube middle layer (Pls on the outside of the inner tube)
(contacting layer), 6... Inner tube outer layer. Patent applicant

Claims (1)

[Scope of Claims] 1. A resin-made pipe comprising at least an inner pipe and a reinforcing layer adjacent to the outside of the inner pipe, the inner pipe inner layer being made of nylon having low permeability to fluorohydrocarbon refrigerants. In the refrigerant hose, the inner tube inner layer is formed to have a wall thickness of 0.1 to 0.5 mm, and the inner tube outer layer or inner tube intermediate layer adjacent to the outside of the inner tube inner layer has a bending elastic modulus of 1500 kg. 1. A hose for a fluorohydrocarbon refrigerant, characterized in that it is made of olefin-modified nylon 11 or 12 with a polyolefin content of 40 to 80 wt% and a wall thickness of 0.5 to 1.5 mm.