JP3208920B2 - Hose for transporting refrigerant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant transport hose suitable as a refrigerant transport piping hose for a car cooler or an air conditioner of an automobile.

[0002]

2. Description of the Related Art
As a refrigerant transport hose, a composite hose in which a gas barrier layer made of a resin layer is arranged inside an inner tube rubber has been proposed for the purpose of preventing gas leakage of Freon as a refrigerant.

In this case, the resin forming the resin layer includes:
(A) Freon R-134a gas barrier property, (b) flexibility enough to be used as a hose, (c) resistance to high temperature refrigerating machine oil flowing in piping (heat resistant oil resistance), (d) high temperature in engine room The ability to withstand the conditions (heat resistance) is required.

In recent years, in order to satisfy these performances, it has been proposed to use a resin which has been subjected to the following treatment for a resin layer. (1) Blend an olefin resin such as an ionomer with a nylon resin. (2) Blend an acid-modified ethylene-propylene rubber (EPR) or an acrylic elastomer having reactivity with an amide group or a carboxyl group in nylon with a nylon resin.

However, although the method (1) can impart flexibility to the nylon, the ionomer melts at around 100 ° C., which is the actual operating temperature range of the resin. In addition, the ionomer is easily attacked by polyalkylene glycol (PAG) oil, which is a refrigerating machine oil for Freon R-134a.

In the method (2), the diffusion coefficient and the solubility of all elastomers except for the butyl rubber in the Freon R-134a gas are extremely large at 100.degree. When the elastomer is mixed in a large amount, the gas barrier property of the resin is deteriorated. Furthermore, EPR has good heat resistance PAG property but is inferior in heat resistance, and acrylic elastomer has good heat resistance but swells in PAG at high temperature, and is inferior in heat PAG property. Have.

As described above, even if a gas barrier layer is formed from the above-described resin, a hose for transporting a refrigerant having sufficiently satisfactory performance cannot be obtained.

[0008] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a refrigerant transport hose excellent in CFC R-134a gas barrier properties, flexibility, heat-resistant oil resistance and heat resistance.

[0009]

According to the present invention, in order to achieve the above object, the innermost layer comprises a sea phase mainly composed of a nylon resin, isobutylene and paramethyl in which a part of hydrogen atoms in the molecule are halogenated. A refrigerant transport hose characterized by being formed from a resin layer having a sea-island structure with an island phase containing a copolymer with styrene (hereinafter abbreviated as a halogenated IB-PMS copolymer).

[0010]

The refrigerant transporting hose of the present invention has the following effects because the innermost layer is formed of a resin layer having a specific sea-island structure.

(1) Halogenated IB-P used for resin layer
MS copolymers have the same compatibility as conventional ionomers and acid-modified elastomers because the side chain halogen groups react with the amide groups in the nylon resin. Excellent in nature. For this reason,
The hose of the present invention does not crack in the inner layer resin even when used at a high temperature of about 150 ° C., and can maintain 100% or more of elongation at break of the inner layer resin even after the heat aging resistance test described below. Can withstand high temperature conditions in the room.

(2) The halogenated IB-PMS copolymer can provide flexibility higher than that of a conventional acid-modified elastomer due to its molecular structure having a structure similar to that of butyl rubber, and has a practical use temperature. R-13 around 100 ℃
4a The gas permeability coefficient is as small as 1/5 to 1/10 of that of a conventional olefin resin or elastomer.

For this reason, the hose of the present invention is excellent in flexibility and has a reaction force of 2.2 k in a hose flexibility test described later.
g · f or less, and the workability of attaching hoses and pipes is high.

In addition, the 100% modulus of the inner tube rubber is 2
0-60kg / cm^Two 100% modulus of outer rubber
15-60 kg / cm^TwoUnder the conditions, hose and piping
If the goal is to improve the workability of installing
The target value of the reaction force measured by the above test method is the hose size
It is as follows separately.

In the case of a hose having an inner diameter of 11 mm and an outer diameter of 19 mm 2.2 kg · f or less In the case of a hose having an inner diameter of 14 mm and an outer diameter of 22 mm 3.4 k
g · f or less 3.5k for a hose with an inner diameter of 15mm and an outer diameter of 23mm
g / f or less 6.4k for a hose with an inner diameter of 19mm and an outer diameter of 27mm
g ・ f or less

Further, the hose of the present invention comprises Freon R-134.
(a) The refrigerant leakage is small, and the gas permeation amount is 4 g / m / 72Hr or less in the gas permeation resistance test described later.

(3) Due to the above-mentioned molecular structure, the halogenated IB-PMS copolymer hardly swells in PAG even at high temperatures due to a large difference in polarity from PAG oil, Excellent in nature. For this reason, the hose of the present invention is resistant to PAG refrigerating machine oil flowing in the piping and does not crack the inner layer resin.
Even after the oiliness test, the elongation at break of the inner layer resin can be maintained at 100% or more.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a hose for transporting refrigerant according to one embodiment of the present invention. In this hose, an inner tube layer 3 composed of a resin layer 1 and an inner tube rubber layer 2 has an intermediate rubber layer 4 containing a reinforcing thread. It is covered with a jacket rubber 5 through the intermediary. In addition,
The hose has a resin layer 1 and an inner tube rubber layer 2 if necessary.
And an adhesive layer can be provided therebetween.

In the present invention, the resin layer, which is the innermost gas barrier layer, has a sea phase made of nylon resin such as nylon 6 or nylon 66 and an island phase made of halogenated IB-PM.
It is formed of a resin having a sea-island structure composed of an S copolymer alone or a mixture of the copolymer and a nylon resin such as nylon 12.

Here, the halogenated IB-PMS copolymer is a copolymer of isobutylene and paramethylstyrene in which some of the hydrogen atoms in the molecule have been replaced by halogen atoms such as bromine and chlorine atoms. , Especially brominated IB-PMS
Copolymers are preferred. Although the halogenation ratio is not particularly limited, the halogen content in the paramethylstyrene molecule is 10 to 80% (% by weight, the same applies hereinafter), particularly 20 to 70%.
% Is preferable. If the content is less than 10%, the compatibility with nylon may be deteriorated.
%, Heat resistance may deteriorate.

The polymerization ratio of isobutylene and paramethylstyrene is preferably 2 to 20% (weight%, hereinafter the same) of paramethylstyrene, particularly preferably 5 to 10%. When the polymerization ratio of paramethylstyrene exceeds 20%, Tg (glass transition point) becomes high, and the properties of the rubber may be lost. On the other hand, when it is less than 2%, the crosslinking efficiency may be deteriorated.

Further, in the above resin, halogenated IB-
The blending ratio of the PMS copolymer is based on the total amount of the nylon resin (the total amount of the nylon resin such as nylon 12 in the sea phase and the island phase when the nylon resin such as nylon 12 is mixed) and the copolymer. On the other hand, it is desirably 15 to 40%. If the compounding ratio is less than 15%, sufficient flexibility may not be provided, and if it exceeds 40%, halogen R
-134a The gas permeability increases, which may result in poor cooling capacity and the need to replenish the refrigerant several times.

When nylon 12 is blended in the island phase, the blending ratio of nylon 12 is 5 to 20% based on the total amount of all nylon resin and halogenated IB-PMS copolymer.
It is preferable that

The above-mentioned resin may further contain additives such as a heat-resistant agent, an anti-aging agent and a processing aid in the sea phase or the island phase, if necessary, in addition to the nylon resin and the halogenated IB-PMS copolymer. Can be added in a range that does not hinder.

In the present invention, such a resin can be produced, for example, by the following method. . (1) After kneading nylon 6 with a halogenated IB-PMS copolymer or a halogenated IB-PMS copolymer and nylon 12 at a predetermined mixing ratio to form a master batch,
This master batch and nylon 6 are kneaded. (2) nylon 6, halogenated IB-PMS copolymer,
If necessary, nylon 12 is blended, and the blend is kneaded with a twin-screw extruder or the like.

The other structure of the refrigerant transport hose of the present invention is not particularly limited, and a normal refrigerant transport hose configuration can be employed. For example, in the refrigerant transport hose shown in FIG. 1, the rubber constituting the inner tube rubber layer 2 is acrylonitrile butadiene rubber (NBR), ethylene-propylene-diene terpolymer (EPD).
M), butyl rubber (IIR), chloroprene rubber (C
R), chlorinated butyl rubber (Cl-IIR), hydrogenated N
BR (H-NBR), a halogenated IB-PMS copolymer, or a rubber obtained by blending at least two types of these rubbers can be used.

Further, in the intermediate rubber layer 4 containing the reinforcing yarn, the reinforcing yarn may be a fiber made of a material such as vinylon, polyester, nylon, or aramid, and may be coated with a spiral or blade structure. it can. The intermediate rubber layer can be a layer such as butyl rubber. In addition, as for the reinforcing yarn, the rubber layer may be omitted and only the reinforcing yarn may be stacked.

The outer covering rubber 5 is made of, for example, EPDM, C
R, H-NMR, halogenated IB-PMS copolymer, I
It can be formed by a rubber layer such as IR and CL-IIR.

In the present invention, the resin layer 1 has a thickness of 0.05 to 0.3 mm in view of the balance between the resistance to Freon transmission and the flexibility.
It is preferable to set the degree. It is preferable that the inner tube rubber layer 2 has a thickness of 1 to 4 mm in view of a balance between moisture permeability and flexibility. Further, the thickness of the intermediate rubber layer 4 including the reinforcing yarn is 1.4.
It is preferable that the thickness of the outer rubber 5 is 1 to 2 mm.

Hereinafter, the present invention will be described more specifically with reference to experimental examples. The components used for the inner tube rubber, the intermediate rubber, and the outer rubber are as shown in Tables 1 to 3, respectively. However, the symbols in the table indicate the following. IIR = butyl rubber EPDM = ethylene-propylene-diene terpolymer DM = Noxeller DM (Ouchi Shinko Chemical Co., Ltd.) TT = Noxeller TT (Ouchi Shinko Chemical Co., Ltd.) M = Noxeller M (Ouchi Shinko Chemical Co., Ltd.) ) Barnock R = morpholine disulfide

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[Experimental Example] A hose similar to the refrigerant transport hose shown in FIG. 1 was manufactured by the following method. That is, first, Table 4
Nylon 6, Nylon 12, brominated IB-PMS copolymer, etc. were kneaded to form a master batch so that the master batch was mixed with Nylon 6
Is kneaded into pellets, and then extruded into a tube with a thickness of about 100 μ on a mandrel using an extruder,
Resin layer 1 was obtained. Nylon 6 and Nylon 12 used here were grade 10 manufactured by Ube Industries, Ltd.
30B and grade 3035B. Also, bromination I
The B-PMS copolymer was XP-50 manufactured by Exxon Chemical Company.
Grade 89-1.

On top of this, an adhesive is applied and dried as required, and an inner tube rubber layer 2 (1.5 m thick) having the composition shown in Table 1 is further added.
m, 11.0 mm inner diameter), followed by a reinforcing thread (vinylon) and an intermediate rubber layer 4 having the composition shown in Table 2, and further covering the outer rubber 5 having a composition shown in Table 3 (thickness: 1. 1m
m, outer diameter of 19.0 mm) to extrude a hose. In addition, vulcanization conditions are 140-170 degreeC and 30-120.
Went in minutes. Using the hose thus manufactured, each test was performed by the following method. The results are shown in Tables 4 to 7. (A) Thermal aging test The resin layer was punched out with a DIN dumbbell,
After heat aging for 10 hours, a 10 mm-wide mark is attached and the elongation at break Eb at a pulling rate of 100 mm / min at 25 ° C.
(%) Was measured.を, 100 when elongation at break is 100% or more
% Is defined as x. (B) Heat-resistant PAG oil property test A sample similar to (a) was heated to 150 ° C. in a closed vessel containing PAG oil (manufactured by Idemitsu Petrochemical Co., Ltd.).
After immersion for 000 hours, the same measurement as in (a) was performed.
A breaking elongation of 100% or more was evaluated as ○, and a breaking elongation of less than 100% was evaluated as ×. (C) Gas permeation resistance 5 hoses conforming to JRA (Japan Refrigeration and Air Conditioning Industry Association Standard)
It was cut into 00 mm, sealed with Freon with an internal volume of 60%, and sealed at both ends. It was left at a temperature of 100 ° C. for 96 hours, and the gas permeation amount between 24 hours and 96 hours was measured.
The numerical value was converted at 72 Hr. 4 g / m / 72 Hr or less was evaluated as ○, and a value larger than 4 g / m / 72 Hr was evaluated as x. (D) Flexibility test As shown in FIG. 2, the rollers 6 were arranged at a span of 200 mm, and the above-mentioned hose 7 was placed thereon. The central part of the distance between the rollers was pressed to bend until the hose kinked, and the maximum pressure (kg · f) generated at that time was measured. A value of 2.2 kg · f or less was evaluated as ○, and a value larger than 2.2 kg · f was evaluated as ×.

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

[Table 6]

[0039]

[Table 7]

From the results of Tables 4 to 7, it was confirmed that the refrigerant transport hose of the present invention was excellent in heat aging resistance, heat resistance to PAG oil, gas permeability, and flexibility.

[0041]

The refrigerant transport hose of the present invention has good flexibility, good workability, excellent heat aging resistance, can withstand high temperature conditions in an engine room, and has excellent gas permeation resistance. It has high R-134a gas barrier properties and excellent heat resistance PAG oil properties. Therefore, the hose of the present invention is suitable as a hose for a refrigerant transport pipe of a car cooler or an air conditioner of an automobile.

[Brief description of the drawings]

FIG. 1 is a schematic view of a hose for transporting refrigerant according to one embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a flexibility test method in an experimental example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin layer 2 Inner tube rubber layer 3 Inner tube layer 4 Intermediate rubber layer containing a reinforcing thread 5 Outer rubber 6 Roller 7 Hose

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-107383 (JP, A) JP-A-5-309790 (JP, A) Patent 2807799 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16L 11/08 B32B 1/08 B32B 25/08 B32B 27/34

Claims (2)

(57) [Claims] A sea-island structure in which an innermost layer has a sea phase mainly composed of a nylon resin and an island phase containing a copolymer of isobutylene and paramethylstyrene in which some of the hydrogen atoms in the molecule are halogenated. A hose for transporting refrigerant, formed from a resin layer having: 2. The hose according to claim 1, wherein the content of the copolymer is 15 to 40% by weight based on the total amount of all the nylon resin and the copolymer.