JPH0486257A - Laminate structure tubular body - Google Patents

Abstract

PURPOSE:To prepare resin of low transmission of chlorofluoro carbon and of superior resistance to chemicals, resistance to heat and resistance to hot oil by making an inner layer of a tubular body composed of a resin composition comprising metaxylylene containing polyamide resin and a specified modified polyester elastomer and having an outer layer composed of a composition comprising polyester elastomer. CONSTITUTION:At least one layer of an inner layer is composed of a polymer containing a constitution unit composed of alpha, omega-aliphatic carboxylic acid with 4-10C xylene diamine composed mainly of metaxylylene diamine at the ratio of 70% or more in the molecule. The inner layer is composed of a resin composition containing modified polyester elastomer prepared by reacting polyamide resin containing metaxylylene, unsaturated carbosylic acid and/or unsaturated carboxylic acid derivative with polyester elastomer. The resin composition is manufactured by using (A) metaxylylene containing polyamide resin and (B) modified polyester elastomer in the range of (A)/(B) 95/5-5/95 in the weight ratio and mixing under heating. Also at least one layer of an outer layer is formed with a composition containing polyester elastomer.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a polyamide resin laminated tubular body having low permeability to fluorocarbon gas, excellent oil resistance, heat resistance, moldability, and flexibility, particularly for automobiles. Polyamide resin-based tubes with the above-mentioned excellent properties are ideal for tubes for air conditioners or electric refrigerators, fluorocarbon gas, which is a refrigerant for home and commercial air conditioners, and oil-resistant tubes for automobile fuel, gasoline, clutch oil, etc. The present invention relates to a laminated tubular body.

[Conventional technology]

Polyamide resins generally have excellent chemical resistance and oil resistance, and are particularly characterized by extremely low permeability to fluorocarbon gas and gasoline. Therefore, it is used in applications that require particularly high reliability, such as high-pressure hose tubes, automotive fuel tubes, and air brake piping tubes. However, polyamide resin is difficult to process and assemble due to its poor flexibility. In order to facilitate these operations, attempts have been made to add plasticizers to polyamide resins to give them flexibility. However, polyamide resins to which plasticizers have been added have the disadvantage that when used for long periods of time under high temperature conditions, the plasticizers flow out and flexibility is lost. In addition, nylon 12
Various polyamide resins, including polyamide elastomers, are very expensive compared to other engineering plastics. Therefore, for example, rubber materials such as nitrile rubber, which is highly flexible and relatively resistant to fluorocarbon gas, are used as tubes for fluorocarbon gas in car air conditioners.

Incidentally, recently, from the standpoint of environmental protection, the use of fluorocarbon gas, which destroys the ozone layer, is being regulated. Especially Freon 1
Since CFC 2 (CC1, F, ) has a large effect on the ozone layer, a shift is being made to use CFC 22 (CHCIF, ), which has a higher vapor pressure than CFC 12 and has less effect on the ozone layer. However, it became clear that the nitrile rubber mentioned above was swollen by Freon 22 and could not be used.

Therefore, a tubular body such as a tube made of a resin that is stable against Freon 22, has barrier properties, has excellent chemical resistance, heat resistance, and oil resistance, and is flexible enough to be easily processed has not been obtained. is the current situation.

[Problem to be solved by the invention]

The present invention solves the above-mentioned conventional problems, and aims to provide a product with extremely low permeability to fluorocarbon gas, excellent chemical resistance, heat resistance, and oil resistance, and flexibility that is easy to process. It is an object of the present invention to provide a tubular body such as a tube made of a resin having the following properties and which can be used as a beaune for fluorocarbons such as car air conditioners. Another object of the present invention is to provide a polyamide resin-based laminated structure tubular body having excellent properties, which is ideal for refrigerant tubes in electric storage units, automobile fuel tubes, and brake oil tubes. be.

[Failure to solve the problem]

The laminated structure tubular body of the present invention has at least one inner layer (A
) a metaxylylene group-containing polyamide resin and (B) a resin composition containing a modified polyester elastomer obtained by reacting an unsaturated carboxylic acid and/or an unsaturated carboxylic acid derivative with a polyester elastomer, and at least one outer layer is made of polyester. It is composed of a composition containing an elastomer.

The resin composition constituting at least one inner layer of the laminated tubular body of the present invention includes (A) metaxylylene group-containing polyamide resin and (B) modified polyester elastomer in a weight ratio of (A)/(B) 95/5 to It is obtained by using a ratio of 5/95 and mixing under heating.

The meta-xylylene group-containing polyamide resin (A) contained in the resin composition constituting at least one inner layer of the laminated tubular body of the present invention refers to xylylene diamine containing meta-xylylene diamine as a main component and a carbon number of α of 10,
It is a polymer containing in the molecule 70 mol% or more of a structural unit formed from an ω-aliphatic dicarboxylic acid.

The xylylene diamine whose main component is metaxylylene diamine is metaxylylene diamine alone or a mixture of metaxylylene diamine and para-xylylene diamine, and the mixture contains 70 mol% or more of metaxylylene diamine. contains.

Such metaxylylene group-containing polyamide resin (A)
Examples include a homopolymer obtained from metaxylylene diamine and the above aliphatic dicarboxylic acid, a copolymer obtained from metaxylylene diamine and paraxylylene diamine and the above aliphatic dicarboxylic acid, and optionally the above polymer. There are copolymers in which small amounts of other monomers are copolymerized in addition to the constituent components.

Homopolymers obtained from the metaxylylene diamine and aliphatic dicarboxylic acid include polymethaxylylene adipamide, polymethaxylylene adipamide, polymethaxylylene adipamide, and the like. Copolymers obtained from the metaxylylene diamine and paraxylylene diamine and aliphatic dicarboxylic acids include metaxylylene-paraxylylene adipamide copolymer, metaxylylene-paraxylylene biveramide copolymer, Examples include metaxylylene-paraxylylene azelamide copolymer. The monomer components contained in the copolymer copolymerized with the above other monomers include aliphatic diamines such as hexamethylene diamine, alicyclic diamines such as piperazine, and hala-his-(2-amino Aromatic diamines such as (ethyl)benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as ε-caprolactam, ω-aminocarboxylic acids such as γ-aminohbutanoic acid, and para-7-minomethylbenzoic acid. There are aromatic aminocarboxylic acids such as.

In the present invention, the metaxylylene group-containing polyamide resin is preferably a polymer having an amino group at the end of the molecule, and the content of the amino group is 3.5 x 10''
Polymers with "equivalent weight/g or more" are preferred. The upper limit of the amino group content is not particularly limited, and for example, a polymer in which all molecular terminals are amino groups can also be used. Such a meta-xylene group-containing polyamide having an amino group at the end of the molecule can be easily produced by appropriately adding diamines such as hexamethylene diamine as a chain transfer agent during its production.

The meta-xylene group-containing polyamide has a relative viscosity of 1.5 or more, preferably 2.0 to 4.0. Relative viscosity is 1.
When it is less than 5, it becomes amorphous and becomes brittle.

Examples of the polyester elastomer used in the production of the modified polyester elastomer (B) contained in the resin composition constituting the inner layer of the present invention include polyester-polyether block copolymers, polyester type block copolymers, etc. .

The above polyester-polyether block copolymer is
It is a block copolymer that has the properties of a rubber-like elastic body because polyester is used as a hard segment and polyether is used as a soft segment, and these segments are arranged alternately and repeatedly.

The acids and alcohols constituting such polyester hard segments are mainly aromatic dicarboxylic acids and alkylene glycols having 2 to 15 carbon atoms, respectively. Specific examples of dicarboxylic acids include terephthalic acid, isophthalic acid, ethylenebis(p-oxybenzoic acid), naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, p-(β-hydroxyethoxy)benzoic acid, etc. It will be done. Specific examples of alkylene glycol include ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-
Examples include dimethyltrimethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohe-+san dimetatool, cyclohexane jetanol, benzene dimetatool, benzene jetanol and the like. As the above-mentioned acid and alkylene glycol, those having a melting point of 200° C. or higher when made into a polyester having a molecular weight sufficient to have fiber-forming ability are suitable.

The polyether constituting the soft segment of the polyester-polyether block copolymer is a polyoxyalkylene glycol having an average molecular weight of about 500 to 5,000. This polyoxyalkylene glycol is
The monomer unit is an oxyalkylene glycol in which the alkylene group has 2 to 9 carbon atoms. in particular,
Suitable examples include poly(oxyethylene) glycol, poly(oxypropylene) glycol, poly(oxytetramethylene) glycol, and the like. The polyether may be a polymer, a random copolymer, a block copolymer, or a mixture of two or more polyethers. Furthermore, the polyether may have a small amount of aliphatic group, aromatic group, etc. in its molecular chain. It may also be a modified polyether containing sulfur, nitrogen, phosphorus, or the like.

The polyester-polyether block copolymer contains 1 to 85 percent polyether units, preferably 5 to 80 percent polyether units.
% by weight, and the polyester units are 99 to 15
It is contained in an amount of 95 to 20% by weight, preferably 95 to 20% by weight.

Examples of the polyester type block copolymer include those obtained by reacting a crystalline aromatic polyester with lactones. Examples of the crystalline aromatic polyester include polymers mainly having ester bonds or ester bonds and ether bonds, having at least one type of aromatic group as a main repeating unit, and having a hydroxyl group at the end of the molecule. .

The crystalline aromatic polyester preferably has a melting point of 150°C or higher when formed into a polymer with a high degree of polymerization.

Suitable examples of crystalline aromatic polyesters can be found in homopolyesters, polyester ethers, copolyesters, copolyester ethers, and the like. Examples of homopolyesters include polyethylene terephthalate, polytetramethylene terephthalate, poly-1°4-cyclohexylene dimethylene terephthalate,
Examples include polyethylene-2,6-naphthalate.

Examples of polyester ethers include polyethyleneoxybenzoate, poly-p-phenylene bisoxyethoxy terephthalate, and the like. Examples of the copolymerized polyester or copolymerized polyester ether include polymers mainly having tetramethylene terephthalate units or ethylene terephthalate units and further having other copolymerization components. Such copolymerized components include:
Tetramethylene terephthalate unit, ethylene isophthalate unit, tetramethylene adipate unit, ethylene sebacate unit, tetramethylene sebacate 141st position,
Examples include ethylene sebacate units, 1,4-cyclohexylene dimethylene terephthalate units, tetramethylene-p-oxybenzoate units, and ethylene-p-oxybenzoate units. The copolymerized polyester and copolymerized polyester ether contain 60 mol% of tetramethylene terephthalate units or ethylene terephthalate units.
It is preferable to include the above.

As the lactone, which is the other component forming the polyester type block copolymer, C-caprolactone is most preferred, but enacitlactone, cabrylolactone, etc. can also be used. Two or more types of these lactones may be used.

The polyester type block copolymer contains the crystalline aromatic polyester and lactones in a weight ratio of 97/3 to 5/9.
It is obtained by copolymerization using a ratio of 95%. Preferably, this weight ratio is 9515 to 30/70. During the above copolymerization, a catalyst is added if necessary, and the mixture is heated and mixed to allow the reaction to proceed.

The polyester elastomer (polyester-polyether block copolymer and/or polyester type block copolymer) thus obtained can be used alone or in combination.
A mixture of two or more species may be used.

The modifier reacted with the polyester elastomer to obtain the modified polyester elastomer (B) is selected from unsaturated carboxylic acids and/or derivatives thereof. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, α
-Ethyl acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endo-bicyclo(2°2.1)hept-5-ene-2,3-dicarboxylic acid (Nadic acid)
, methyl-endocys-bicyclo(2,2,1)hept-5-ene-2°3-dicarboxylic acid (methylnadic acid). Derivatives of unsaturated carboxylic acids include acid halides, amides, imides, acid anhydrides,
Examples include derivatives such as esters. Specific examples include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, unsaturated dicarboxylic acids or unsaturated dicarboxylic acid anhydrides are preferred, and maleic acid, nadic acid, or acid anhydrides thereof are particularly preferred.

These modifiers are used in amounts ranging from about 0.01 to about 20%, preferably from about 0.02 to about 20% by weight, based on the polyester elastomer.

If it is less than 0.01% by weight, the effect of improving the physical properties of the metaxylylene group-containing polyamide resin is small. If it exceeds 20% by weight, gelation tends to occur during the reaction (step 4).

The method of reacting the modifier with the polyester elastomer is not particularly limited, but it is desirable to prevent undesirable components such as gel from being contained in the resulting modified polyester elastomer. Specifically, for example, the above polyester elastomer, a modifier, and a radical generator are blended and melt-kneaded to cause a reaction and obtain a modified polyester elastomer. As the radical generator, known organic peroxides or diazo compounds can be used. Specifically, benzoyl peroxide,
Examples include dicumyl lebaoxide, di-butyl peroxide, L-butylcumyl peroxide, cumene hydroperoxide, and azobisisobutyronitrile. The amount of the radical generator used is 0.05% by weight or more, preferably 0.1 to 1.5% by weight, based on the polyester elastomer.

In the resin composition constituting the inner layer according to the present invention, the weight ratio (A) / (B) of the metaxylylene group-containing polyamide resin (A) and the modified polyester elastomer (B)
is preferably 9515 to 5/95, and more preferably (A)/(B) is 90/10 to 10/90. When the weight ratio of the modified polyester elastomer (B) is less than 5, that is, the polyamide resin (A)
If the weight ratio is greater than 95, impact resistance, flexibility, etc. will not be improved. When the weight ratio of the modified polyester elastomer (B) is greater than 95, that is, the polyamide resin (A
) If the weight ratio is less than 5, water resistance etc. will decrease.

The resin composition constituting the inner layer according to the present invention may further contain other additives. Examples of additives that can be used include colorants, stabilizers, inorganic fillers, organic fillers, fibrous reinforcing agents, and other various auxiliaries.

Usually, the metaxylylene group-containing polyamide resin (A) and the modified polyester elastomer (B) are mixed under heating, and the above additives are added at any of the initial stage, middle stage, or final stage of mixing. It is possible. A conventionally known device can be used for the above mixing. For example, a reactor with stirring blades, a -axial or twin-screw extruder,
Kneading devices such as a Banbury mixer, kneader, and mixing roll can be used alone or in combination.

The heating and mixing temperature is preferably higher than the melting point of the metaxylylene group-containing polyamide resin (A) and the modified polyester elastomer (B).

Further, the polyester elastomer used for the outer layer of the laminated tubular body according to the present invention includes the same polyester elastomer as the polyester elastomer used for the resin composition constituting the inner periphery, and both modified and unmodified polyester elastomers can be used.

A modified polyester elastomer (B) obtained by grafting a metaxylylene group-containing polyamide resin (A) with a modifier selected from unsaturated carboxylic acids and derivatives thereof.
) is mixed under heating, it is presumed that the graft-reacted carboxylic acid and/or its derivative and the amino terminal group of the metaxylylene group-containing polyamide resin partially react. It is presumed that this reaction promotes uniform miscible dispersion of the metaxylylene group-containing polyamide resin and the modified polyester elastomer, and in this way, the resin composition used for the inner layer has excellent properties of the metaxylylene group-containing polyamide resin (value). It is possible to add flexibility, impact resistance, etc. while maintaining the properties.

Furthermore, by using a polyester elastomer for the outer layer, the adhesiveness between the inner layer and the outer layer of the obtained tubular body is improved, and even when the obtained tubular body is bent, the inner layer and the outer layer do not separate.

The laminated tubular body of the present invention is manufactured by, for example, a coextrusion method in which an extruder is connected to each of a pair of tube dies arranged concentrically.

At this time, there is a method in which pellets of meta-xylylene group-containing polyamide resin and pellets of modified polyester elastomer prepared in advance as described above are supplied to a die for forming the inner layer of the tubular body and mixed; A method of using elastomer that has been kneaded in advance and made into pellets;
Method of forming a modified polyester elastomer and simultaneously mixing it with a metaxylylene group-containing polyamide resin by charging a metaxylylene group-containing polyamide resin, a polyester elastomer (unmodified), a modifier, and a radical generating agent into an extruder and melt-kneading them. and so on. If desired, other additives may be added at the same time and melt-kneaded.

A die for forming the outer layer is charged with a polyester elastomer and optionally additives, and then melt-kneaded. Two or more dies for forming the inner layer and the outer layer may be connected as necessary.

The thickness of the inner layer of the laminated tubular body of the present invention is preferably 0.01 m or more and 1.0 m or less. Inner layer thickness is 0.01a
If it is less than 1 m, gas barrier properties may be lacking;
, the tubular body obtained lacks flexibility when it exceeds OR.

As described above, since the laminated structure tubular body of the present invention contains the metaxylylene group-containing polyamide resin (A,) in the inner layer, it has low permeability to aron gas, especially Freon 22, does not cause deterioration, and has good oil resistance and heat resistance. It is also excellent. Furthermore, since the outer layer is made of polyester elastomer, it is highly flexible and has good adhesion between the inner and outer layers. Such a laminated tubular body can be used in many fields such as refrigerant tubes and hoses of near conditioners for automobiles, gasoline supply tubes, and hoses.

〔Example〕

The invention will now be described with reference to examples.

In the following examples, metaxylylene group-containing polyamide resin: (1) Relative viscosity 2.20 (in 98% sulfuric acid: 1 g/100
rIL 1125°C) polymethaxylylene adipamide (hereinafter referred to as MXD-6), or (2) metaxylylene adipamide 90% and ε-caprolactam 10
A copolymer having a relative viscosity of 2.12 (hereinafter referred to as Go-M) obtained by reacting % by weight was used. These resins were vacuum dried at 100° C. for 16 hours before use.

As a polyester elastomer; ■Polyether-polyester elastomer of polytetramethylene glycol and polytetramethylene terephthalate (Toyobo FjD Co., Ltd., Pelprene P150B)
or (2) A polyester block copolymer of polycaprolactone and polytetramethylene terephthalate (Perprene S-1000 manufactured by Toyobo Co., Ltd.) was used.

Production Example Production of modified polyester elastomer: The maleic anhydride-modified polyester elastomers (1) and (2) above (referred to as (1) and (1), respectively) were synthesized as follows.

100 parts by weight of (1) or (2), 0.5 parts by weight of maleic anhydride, and 0.3 parts by weight of dicumyl peroxide were uniformly mixed with a mixer. This mixture was fed to a 30-line twin-screw extruder, and a maleic anhydride modification reaction was carried out at a cylinder temperature of 200-230°C. The reaction products thus obtained were dried in a vacuum dryer at 80° C. for 12 hours to obtain modified polyester elastomers 1-1 and 2-1, respectively.

Examples 1 to 6 (A) The above metaxylylene group-containing polyamide resin (M
XD-6) or (Go-M) and the modified polyester elastomer ■-1 or ■-1 obtained in the production example were triblended at the ratios shown as compositions 1 to 6 in Table 1, and then A pellet was produced using a twin screw extruder. The cylinder temperature at that time was 240°C in the case of 260'C1Co-M in the case of MXD L6.The obtained pellets were vacuum dried at 70°C for 16 hours and used as a material for the inner layer.

As the polyester elastomer for the outer layer, the polyester elastomer (1) or (2) above was used as it was without modification.

(B) Manufacture of laminated structure tubular body: An extruder (■) (diameter 30 m) is placed on the inner layer side of a pair of tube dies arranged concentrically, and an extruder (■) is placed on the outer layer side.
(30 pieces in diameter) were connected to each other.

The extruder was charged with pellets of the metaxylylene group-containing polyamide resin and modified polyester elastomer constituting the inner layer, and the extruder (■) was charged with polyester elastomer pellets. The cylinder temperature in the extruder was set to 240 to 260°C, and that of extruder (II) was set to 220°C, and coextrusion was carried out, and by the vacuum box sizing method, the inner diameter was 10mm and the outer diameter was 1211E.
A tubular body having an inner layer and an outer layer having the structure shown in Table 2 was obtained.

(C) Evaluation of laminated structure tubular body: Using the tubular body obtained as described in item (B) above, the amount of deflection δ is measured from the following relationship, and the elastic modulus E is determined from the bending rigidity EI to determine the flexibility. expressed gender.

Furthermore, the interlayer interface between the inner layer and the outer layer was observed when it was bent, and the presence or absence of peeling was investigated. Those with no peeling are marked with ○, and those with peeling are marked with ×. The results are shown in Table 2.

Next, a new tubular body 80crIL obtained as described in the above section (B) was prepared, and a hose for automobile cooling equipment according to the Japan Refrigeration and Air Conditioning Industry Association standards (JRA2001-1976) was prepared.
The permeability of Freon 22 was tested by applying the Freon gas permeation test (high pressure) for hose assemblies described in section ). The above tubular body is filled with Freon 22, and placed in a 100°C air constant temperature bath.
The sample was left to stand for 6 hours, and the weight difference before and after the stand was calculated, and the gas permeability (g/m/72 hours) was determined.

The results are shown in Table 2.

Table 1 Resin composition for inner layer Comparative composition 7 uses nylon 6 with a relative viscosity of 2.53.
In Composition 8, nylon 6.6 with a relative viscosity of 2.51 was used, and the cylinder temperature of the extruder was 240°C and 270°C during kneading in a twin-screw extruder, respectively. was also performed at the same temperature.

The rest was carried out in the same manner as for the metaxylylene group-containing polyamide resin.

Comparative Examples 1 to 3 A tubular body having an outer layer having the structure shown in Table 2 was obtained using nylon 6 (comparative composition 7) or nylon 6.6 (comparative composition 8) that does not contain metaxylylene groups in the inner layer. Ta.

Comparative Examples 4-5 MX containing no modified polyester elastomer in the inner layer
Tubular bodies having the configuration shown in Table 2 were obtained using D-6 or nylon 6 as is.

Comparative Example 6 A single-layer tubular body made only of unmodified polyester elastomer was produced. The tubular bodies of these comparative examples are Examples 1 to 6.
The test was conducted in the same manner as above, and the results are shown in Table 2.

Comparative Example 7 In place of the modified polyester elastomer in Example 1, an unmodified polyester elastomer as shown in Comparative Composition 9 in Table 1 was used to constitute the inner layer, and a tubular body was produced in the same manner.

From Table 2, it can be seen that the laminated structure tubular body of the present invention has a very low permeability of Freon 22, and is also highly flexible, and no peeling between the resin layers is observed even when it is bent. On the other hand, for those using nylon 6 and nylon 6゜6, which do not contain metaxylylene groups, in the inner layer (Comparative Examples 1 to 3), no flexibility or interfacial peeling was observed, but the transmittance of Freon 22 was very high. It has become. Furthermore, Comparative Example 4 is excellent in that the transmittance of Freon 22 is small, but the flexibility is insufficient. Similarly, in Comparative Example 5, satisfactory flexibility and Freon 22 transmittance cannot be obtained. Although Comparative Example 6 has excellent flexibility, the transmittance of Freon 22 becomes high and it cannot be used as is. In Comparative Example 7, phase separation was observed in the inner layer resin, and at the same time peeling between the layers was observed, and therefore the permeability of Freon 22 also increased. Furthermore, the viscosity of the inner layer resin was low, making it difficult to manufacture the tubular body.

〔Effect of the invention〕

The laminated tubular body of the present invention has extremely low froncus permeability and excellent chemical resistance, heat resistance, and oil resistance.
Moreover, a laminated tubular body having flexibility and easy processing is provided. The laminated tubular body of the present invention can be used in many fields such as refrigerant hoses for automobile near conditioners, gasoline supply tubes, hoses, and home refrigerator hoses.

Claims (1)

[Claims] 1. At least one inner layer of the tubular body contains (A) a metaxylylene group-containing polyamide resin, and (B) a modified polyester elastomer obtained by reacting an unsaturated carboxylic acid and/or an unsaturated carboxylic acid derivative with a polyester elastomer. 1. A tubular body having a laminated structure, characterized in that the tubular body is made of a resin composition containing a polyester elastomer, and at least one outer layer is made of a composition containing a polyester elastomer.