JPH01308455A - Gas-impermeable resin composition - Google Patents

Abstract

PURPOSE:To improve the flexibility and gas impermeability of a molding, by mixing a poly(ether)-ester-amide resin with an ethylene/vinyl acetate copolymer saponificate. CONSTITUTION:A polyester component (A) comprising a dicarboxylic acid and a low-molecular diol is polycondensed with a polyamide component (b) comprising at least one member selected from among an omega-amino acid, an omega-lactam and a diamine and a dicarboxylic acid in an amount to give a weight ratio (a/b) of 5-50/95-5 to obtain a polyester-amide resin (A). Separately, a polymer diol is polycondensed with component (a) or a dicarboxylic acid and component (b) to obtain a polyether-ester-amide resin (B) having a weight ratio (c/d) (wherein (c) is a polyether ester component, and (d) is a polyamide component) of 10-40/90-60. Component A and/or component B is mixed with an ethylene/vinyl acetate copolymer saponificate (C) of an ethylene content <=80mol % and a degree of saponification of vinyl acetate >=90mol % in an amount to give a weight ratio (component A and/or component B/component C) of 5-90/95-10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas-impermeable resin composition used as a molding material for members that require flexibility as well as gas-impermeability.

[Conventional technology]

Conventionally, resins such as nylon 6 have been used for members that require gas impermeability. However, resins that are highly gas-impermeable, such as the above-mentioned nylon 6, usually have high rigidity, so they are often not suitable for use as they are in members that require flexibility as well as gas-impermeability.

For example, as shown in Fig. 5, a refrigerant transport hose used for car coolers, air conditioners, etc., has a three-layer structure consisting of an inner tube rubber layer 1, a fiber reinforced layer 2, and an outer tube rubber layer 3. Although such rubber hoses are highly flexible and have excellent piping workability, each rubber layer has gas permeability, so refrigerant gas gradually leaks from the hose and decreases. It has the disadvantage of causing Therefore, if a constant cooling capacity is to be maintained, gas charging must be performed frequently, which causes many problems in terms of maintenance.

Therefore, it has been proposed to use a resin material with excellent gas impermeability in the inner tube rubber layer 1 instead of the rubber material or in combination with the rubber material. However, when nylon 6 is used as the resin material, the rigidity of nylon 6 is high and the flexibility of the hose is significantly impaired, which poses a problem.

[Problem that the invention seeks to solve]

In this way, conventionally known gas-impermeable resins generally have poor flexibility, so they cannot be applied directly to parts that require flexibility as well as gas-impermeability, such as refrigerant transport hoses and packing. is insufficient.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a gas-impermeable resin composition that has excellent gas impermeability and can be made into a flexible molded product.

[Means for solving problems]

In order to achieve the above object, the gas-impermeable resin composition of the present invention comprises at least one of a polyesteramide resin and a polyetheresteramide resin, and an ethylene-
The main component is saponified vinyl acetate copolymer. In addition, in this invention, "main component"
This includes cases where the whole is composed of only the main components.

[Effect]

That is, as a result of repeated research on resin materials that have gas impermeability and flexibility at the same time by combining various resins, the present inventors found that saponified ethylene-vinyl acetate copolymer and "-lyesteramide resin" and a small amount of polyether ester amide resin (by combining one with the other, it became possible to simultaneously satisfy both gas impermeability and flexibility, which were previously impossible to satisfy at the same time), and arrived at this invention. .

Next, this invention will be explained in detail.

The saponified ethylene-vinyl acetate copolymer used in this invention usually has an ethylene content of 80 mol% or less and a saponification degree of vinyl acetate of 90 mol% or more. In other words, saponified ethylene-vinyl acetate copolymers with an ethylene content of more than 80 mol% and a saponification degree of vinyl acetate of less than 90 mol% tend to have insufficient gas impermeability effects. This is because it will be done.

In addition, the polyesteramide resin used together with the saponified ethylene-vinyl acetate copolymer contains dicarboxylic acid and low-molecular diol as polyester components, and at least one of ω-amino acids, ω-lactams, and diamines as polyamide components. Those obtained by polycondensation with dicarboxylic acids are preferred. The dicarboxylic acids of the polyester component include aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, dicyclohexyl-4,4-dicarboxylic acid, etc. Examples include alicyclic dicarboxylic acids and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and dodecanoic acid. Examples of the low-molecular diol of the polyester component include aliphatic diols such as ethylene glycol, trimethylene glycol, 1,4-butanediol, and hexamethylene glycol, alicyclic diols such as 1,4-cyclohexane dimetatool, and xylylene. Examples include aromatic diols such as glycols. In addition, the ω-amino acids of the polyamide component include ω-aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid, ω-aminopelargonic acid, ω-aminocapric acid, ω-aminoundecanoic acid, and ω-aminoundecanoic acid. Examples include dodecanoic acid. Examples of the ω-lactam include ε-cabrolactam, ω-enantholactam, ω-capryllactam, and ω-laurolactam. Further, examples of the diamine of the polyamide component include hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, and the like. The polyester amide resin used in this invention is based on the weight of the polyester component (A) and the polyamide component (B), A/B=5/9.
It is preferable to react at a ratio of 5 to 50,150.

Furthermore, the polyether ester amide resin used together with the above polyester amide resin or in place of the above polyester amide resin includes: (1) high molecular diol, (2) the above polyester component (dicarboxylic acid and low molecular diol) or the polyester component in this polyester component. Preferably, a dicarboxylic acid is polycondensed with the above polyamide component (ω-amino acid, etc. and dicarboxylic acid). Examples of the polymer diols mentioned above include polyethylene glycol, poly(
1,2-propylene oxide) glycol, poIJ(1
, 3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, and the like. In the polyether ester amide resin used in this invention, the ratio of the polyether ester component (C) to the polyamide component (D) is preferably set to C/D = 10/90 to 40/60 on a weight basis. It is.

Although such the above-mentioned polyether ester amide resin and the above-mentioned polyester amide resin are resin materials,
It has flexibility, and by combining it with the saponified ethylene-vinyl acetate copolymer, it can become a molded product that is flexible and highly gas impermeable.

The gas-impermeable resin composition of the present invention can be obtained using the above-mentioned resin raw materials according to a method for obtaining ordinary resin compositions. For example, it can be obtained by triblending pellets of a saponified ethylene-vinyl acetate copolymer with pellets of a polyesteramide resin or a polyetheresteramide resin, and then kneading the resultant mixture using a two-wheel screw extruder. At this time, at least one of the polyesteramide resin and the polyetheresteramide resin (P) and the saponified ethylene-vinyl acetate copolymer (E
) and the mutual blending ratio is ・, on a weight basis, P/E=5/
It is suitable to set it in the range of 95 to 90/10, particularly 10/90 to 80/20. If more than 95% by weight of the saponified ethylene-vinyl acetate copolymer is blended, the gas impermeability will improve, but the resulting molded product will have increased rigidity, which is not preferable. On the other hand, if less than 10 parts of the saponified ethylene-vinyl acetate copolymer are added, the resulting molded product will have good flexibility, but the gas impermeability will be insufficient, which is not preferable.

In addition to the above-mentioned components, the gas-impermeable resin composition of the present invention also contains chlorosulfonated polyethylene rubber (C3
M), chlorinated polyethylene (CPE), epichlorohydrin rubber (CHC, CHR), chlorinated butyl rubber (Cf!
, -IIR), ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene copolymer (NBR), and other rubbers may be contained. The mixing ratio of the composition (X) of at least one of the saponified ethylene-vinyl acetate copolymer, polyester amide resin, and polyether ester amide resin and the rubber (Y) is, on a weight basis, X/Y= 60/
It is preferable to set it within the range of 40 to 10010.

The gas-impermeable resin composition of the present invention can be used, for example, as a material for forming the inner tube of a refrigerant transport hose as shown in FIG. In the figure, 11 is a resin layer formed of a resin composition whose main components are at least one of a polyesteramide resin and a polyetheresteramide resin and a saponified ethylene-vinyl acetate copolymer;
2 is an outer rubber layer, 13 is a fiber-reinforced layer, 14 is an outer tube rubber layer, and 15 is a spiking hole for releasing gas accumulated between the eyebrows to the outside, which extends from the outer tube rubber layer 14 to the fiber-reinforced layer 13. . Note that the refrigerant transport hose is not limited to the one in which the inner tube has a two-layer structure as shown in FIG. 1, but may have a structure as shown in FIGS. 2 to 4. That is, in the case shown in FIG. 2, only the resin layer 11 is formed of the resin composition whose main components are at least one of a polyesteramide resin and a polyetheresteramide resin and a saponified ethylene-vinyl acetate copolymer. It is composed of The one in Figure 3 has an inner tube with a three-layer structure, the innermost layer being the inner rubber layer 10, and the outer layer mainly containing at least one of polyesteramide resin and polyetheresteramide resin and saponified ethylene-vinyl acetate copolymer. A resin layer 11 is formed from a resin composition as a component, and a rubber layer 12 is arranged on the outside of the resin layer 11. Further, in the case shown in FIG. 4, contrary to the case shown in FIG. 1, the innermost layer is a rubber layer 10, and a resin layer 11 is arranged outside of the rubber layer 10.

In the refrigerant transport hose, the resin layer 11 of the inner tube is formed of the special resin composition of the present invention, so the resin composition itself has excellent flexibility and gas impermeability. Gas impermeable.

[Effects of the Invention] As described above, the gas-impermeable resin composition of the present invention has the following properties:
Molding materials for refrigerant transportation hoses for car coolers and air conditioners, and packing materials that require long-term sealing and gas impermeability, as they can be molded products that are highly flexible and gas-impermeable. It also has properties that make it ideal for use as a material for food and drug containers, packaging materials, wrapping films, etc.

Next, examples will be described together with comparative examples.

[Examples 1 to 8, Comparative Examples 1 to 3] The raw materials shown in Table 1 below were blended according to the proportions below,
A target gas-impermeable resin composition was obtained according to the above manufacturing method.

(Left below) Using each of the resin compositions a to f obtained in this way,
A hose having the structure shown in FIG. 1 was prototyped using the following procedure. In addition, when the inner tube had a three-layer structure, a tubular body was obtained by first extruding an unvulcanized rubber composition for forming an inner rubber layer onto a rubber mandrel from an extrusion molding machine. The rest was manufactured according to the following manufacturing method.

(1) - On a rubber mandrel, extrude the molten resin obtained by heating and melting the resin composition from a resin extruder to make a resin Ji
11 and cooled.

(2) After applying an adhesive to the outer peripheral surface of the resin layer 11, an unvulcanized rubber composition for forming the outer rubber layer 12 is extruded from an extrusion molding machine to form an inner tube with a three-layer structure. obtain.

(3) After applying an adhesive to the outer circumferential surface of the inner tube, the yarn for the fiber reinforcement layer 13 is braided, etc. to form the fiber reinforcement layer 13.
form.

(4) After applying an adhesive to the outer circumferential surface of the fiber reinforced layer 13, an unvulcanized rubber composition for forming the outer tube rubber layer 14 is extruded thereon using an extrusion molding machine.

(5) After the laminated tubes are vulcanized and bonded to integrate them, the mandrel is removed. However, the vulcanization conditions are usually temperature 1
Set at 45-170°C for 1 hour and 30-90 minutes.

The material, thickness, etc. of each layer were in accordance with Table 2 below.

Further, in the same manner as above, the resin layer 11 is made of NBR, and the inner tube is made of NBR.
Three types of hoses were made as comparative examples: one made of a single layer, one made of a saponified ethylene-vinyl acetate copolymer, and one made of a polyesteramide resin.

And for each hose obtained in this way,
The flexibility and gas impermeability of the hose were evaluated. The results are also shown in Table 2 below.

In addition, each evaluation was performed as follows.

<Flexibility> The hose was cut into 300 mm or 400 mm, one end was fixed on a flat plate, and the other end was bent to reach the flat plate.The bending stress required to reach the flat plate was measured and evaluated. A smaller value indicates greater flexibility.

Gas impermeability〉 The hose was cut into 500 mm length, filled with 40 g of Freon 12 and sealed at both ends, left in an atmosphere of 10°C for 72 hours, and then the overall weight was measured. The number of grams of Freon permeated was determined and evaluated in comparison with the weight. The smaller the value, the better the gas impermeability.

(The following is a blank space) From the above results, it can be seen that the example products are excellent in both flexibility and gas impermeability. On the other hand, in Comparative Example 1, in which the inner tube was composed of a single layer of NBR, a large amount of gas permeated therethrough, making it impractical. In addition, two comparative examples in which the resin layer was formed only with saponified ethylene-vinyl acetate copolymer had excellent gas impermeability but poor flexibility, and compared with those in which the resin layer was formed only with polyesteramide resin. On the contrary, it can be seen that the product of Example 3 has good flexibility but poor gas impermeability.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view of one application example of this invention, Figures 2 and 3 are
4 and 4 are longitudinal cross-sectional views of other application examples of the present invention, and FIG. 5 is a longitudinal cross-sectional view of a conventional refrigerant transport hose. 11...Resin layer patent applicant Tokai Rubber Industries Co., Ltd. Agent Patent attorney Yukihiko Nishi Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A gas-impermeable resin composition comprising as main components at least one of a polyesteramide resin and a polyetheresteramide resin, and a saponified ethylene-vinyl acetate copolymer.