JP2006266319A - Low permeability resin hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-permeability resin hose having improved adhesive force between an outer layer and a layer in contact therewith without providing a bonding layer therebetween. <P>SOLUTION: The low-permeability resin hose comprises a tubular inner layer 1 and the outer layer 3 provided on the outer periphery thereof. The inner layer 1 is formed of a polyamide resin, and the outer layer 3 is formed of a mixture of a high-amino-number polyamide resin and an acid modification polyolefin resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a low-permeability resin hose, and more specifically, gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied) used in automobiles and the like. The present invention relates to a low-permeability resin hose excellent in permeation resistance to refrigerants such as petroleum gas) or refrigerants such as chlorofluorocarbons, alternative chlorofluorocarbons, water, and carbon dioxide used in air conditioners and radiators.

  Due to growing global environmental awareness, regulations on the evaporation of hydrocarbons from fuel hoses for automobiles and the like have been strengthened, and in particular, strict regulations on transpiration in the United States have been legislated. Under such circumstances, in order to comply with the regulation of the amount of hydrocarbon transpiration, for example, various multi-layered hoses as described below have been proposed.

[Hose A]
A bonding layer made of polyolefin between an outer layer made of polyamide 11 (PA11) or polyamide 12 (PA12) and an inner layer or an intermediate layer made of polyamide 6 (PA6) or ethylene-vinyl alcohol copolymer (EVOH) Hose (see Patent Documents 1 and 2, for example).

[Hose B]
An inner layer made of polyamide 6 (PA6), an intermediate barrier layer made of ethylene-vinyl alcohol copolymer (EVOH), and an outer layer made of polyamide 12 (PA12), A hose provided with a bonding layer made of copolyamide 6/12 between the outer layer (see, for example, Patent Document 3).
European Patent No. 0428833 European Patent No. 0428834 Special table 2003-535717

[Hose A Challenge]
Since the layer made of PA6 and the layer made of EVOH of the hose A are bonded to each other by heat fusion such as coextrusion, it is not necessary to provide a bonding layer between the PA6 layer and the EVOH layer. On the other hand, the PA6 or EVOH layer of the hose A and the outer PA11 layer and PA12 layer do not adhere to each other by heat fusion such as co-extrusion. A bonding layer is provided between the layer made of PA6 or EVOH and the outer layer, whereby the two layers are adhered to each other. However, in the case of the hose A having such a configuration, for example, when bending is performed by heating after manufacturing a straight pipe, the bonding layer is melted and peeled off by heat during heating (usually about 160 ° C.) There are difficulties. In addition, since the above-mentioned bonding layer is formed, the capital investment cost is required accordingly, so that there is a problem that the product cost is increased as a whole. Furthermore, since the bonding layer using the modified polyolefin lacks reliability such as heat resistance, it is not preferable to use it as a fuel tube in an engine room having severe high temperature characteristics.

[Problems with hose B]
In the above-mentioned hose B, copolyamide 6/12 (polyamide 6/12 copolymer) used for interlayer adhesion may be deteriorated in heat aging tests or the like, and is inferior in heat resistance reliability. There are difficulties.

  Thus, without providing a bonding layer between the outer layer and the layer in contact with the outer layer (for example, the inner layer / outer layer or the intermediate barrier layer / outer layer), the interlayer adhesion between both layers including the reliability is excellent. The low permeability resin hose has not been obtained yet, and the appearance of such a low permeability resin hose is expected.

  The present invention has been made in view of such circumstances, and its object is to provide a low-permeability resin hose excellent in interlayer adhesion between both layers without providing a bonding layer between the outer layer and the layer in contact therewith. And

  In order to achieve the above object, the low-permeability resin hose of the present invention is a low-permeability resin hose having a tubular inner layer and an outer layer provided on the outer periphery thereof, and the inner layer uses a polyamide-based resin. And the outer layer is formed using a mixture of a high amino-value polyamide-based resin and an acid-modified polyolefin-based resin.

  That is, this inventor repeated earnest research in order to obtain a low-permeability resin hose excellent in interlayer adhesion between both layers without providing a bonding layer between the outer layer and the layer in contact therewith. And while forming the outer layer of the low-permeability resin hose using a mixture of the high amino-value polyamide-based resin and the acid-modified polyolefin-based resin, and forming the inner layer of the low-permeability resin hose using the polyamide-based resin, It was found that the interlayer adhesion between the two layers was good and it was not necessary to provide a bonding layer between the two layers, and the present invention was reached. That is, by setting the amino value of the polyamide resin in the outer layer to a high amino value, the reactivity (or compatibility) between the amino group of the polyamide resin in the outer layer and the carboxyl group of the polyamide resin in the inner layer In addition, the reactivity (or compatibility) between the functional group (acid-modified group) of the acid-modified polyolefin resin in the outer layer and the amino group of the polyamide-based resin in the inner layer increases, so the inner layer and the outer layer It is thought that the interlayer adhesion with

  As described above, the low-permeability resin hose of the present invention forms the outer layer of the low-permeability resin hose using a mixture of a high amino value polyamide-based resin and an acid-modified polyolefin resin, and uses the polyamide-based resin. The inner layer of the low permeability resin hose is formed. Therefore, as described above, the interlayer adhesion between the inner layer and the outer layer becomes good, and there is no need to provide a bonding layer between the two layers. As a result, problems such as heat aging are solved, and the heat resistance reliability is excellent. Further, the material cost itself can be reduced, and the capital investment for one extruder for forming the bonding layer and the investment for the round die can be suppressed.

  Further, when an intermediate barrier layer using an ethylene-vinyl alcohol copolymer is formed between the inner layer and the outer layer, an effect of further improving the low permeation performance can be obtained. In this case, the reactivity of the amino group of the polyamide resin in the outer layer and the functional group of the acid-modified polyolefin resin (acid-modified group) with the OH group of the ethylene-vinyl alcohol copolymer in the intermediate barrier layer (or It is considered that the interlaminar adhesion between the intermediate barrier layer and the outer layer is improved.

  Next, embodiments of the present invention will be described in detail.

  For example, as shown in FIG. 1, the low-permeability resin hose of the present invention is configured by forming an intermediate barrier layer 2 on the outer peripheral surface of a tubular inner layer 1 and further forming an outer layer 3 on the outer peripheral surface thereof.

  In the present invention, the inner layer 1 is formed using a polyamide-based resin, and the outer layer 3 is formed using a mixture of a high amino-value polyamide-based resin and an acid-modified polyolefin-based resin. These are the biggest features.

  Examples of the polyamide-based resin forming the inner layer 1 include aliphatic polyamide resins and aromatic-containing polyamide resins. These may be used alone or in combination of two or more.

  Examples of the aliphatic polyamide resin include polyamide 6 (PA6) and polyamide 66 (PA66). Examples of the aromatic-containing polyamide resin include polyamide MXD6, polyamide 9T (PA9T), polyamide 6T (PA6T), and the like. Among these, PA6 is preferably used because it is excellent in material cost and property balance (low permeability, heat deterioration resistance, elastic modulus, elongation, etc.).

  In addition to the polyamide-based resin, the inner layer material forming the inner layer 1 may be appropriately mixed with a plasticizer, an anti-aging agent, a flame retardant, an impact resistant material, and the like as necessary. .

  The intermediate barrier layer material for forming the intermediate barrier layer 2 is not particularly limited, and examples thereof include an ethylene-vinyl alcohol copolymer (EVOH).

  The material for the intermediate barrier layer mainly comprises a vinyl aromatic monomer polymer block and an optionally hydrogenated conjugated diene polymer block in addition to the ethylene-vinyl alcohol copolymer (EVOH). A block copolymer, a rubber softener, a modified elastomer having a functional group capable of reacting with the EVOH, a polyolefin resin, and the like may be appropriately blended as necessary.

  Next, as an outer layer material for forming the outer layer 3, a mixture of a high amino-value polyamide-based resin and an acid-modified polyolefin-based resin is used as an essential component.

  The polyamide resin having a high amino value is not particularly limited. For example, polyamide 6 (PA6), polyamide 66 (PA66), polyamide 99 (PA99), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 11 (PA11), polyamide 910 (PA910), polyamide 912 (PA912), polyamide 12 (PA12), a copolymer of polyamide 6 and polyamide 66 (PA6 / 66), and the like. These may be used alone or in combination of two or more. Among these, PA12, PA11, PA910, and PA912 are preferably used because they are excellent in calcium chloride resistance.

  The high amino value polyamide-based resin preferably has a terminal amino group concentration of 40 µequivalent / g or more, particularly preferably in the range of 50 to 80 µequivalent / g. That is, when the terminal amino group concentration of the polyamide-based resin is less than 40 μequivalent / g, the adhesiveness to the intermediate barrier layer 2 tends to be inferior. When the terminal amino group concentration of the high amino-value polyamide-based resin exceeds 80 μeq / g, the molecular weight of the polyamide-based resin decreases, so that the workability tends to deteriorate in terms of melt viscosity during molding. Moreover, since the physical properties of the molded article tend to be deteriorated, the polyamide resin having a high amino value is preferably one having a terminal amino group concentration in the range of 40 to 80 μeq / g.

  Here, the terminal amino group concentration of the high-amino-value polyamide-based resin can be measured, for example, as follows. That is, a predetermined amount of polyamide-based resin is put into an Erlenmeyer flask with a stopcock, 40 ml of a previously prepared solvent [phenol / methanol = 9/1 (volume ratio)] is added, and the mixture is stirred and dissolved with a magnetic stirrer. It can be determined by titrating with 0.05 N hydrochloric acid using thymol blue.

  The acid-modified polyolefin resin used together with the high amino value polyamide-based resin is not particularly limited, and examples thereof include those obtained by modifying a polyolefin resin with a modifier such as an unsaturated carboxylic acid.

  Examples of the polyolefin resin in the acid-modified polyolefin resin include thermoplastic resins obtained by polymerizing or copolymerizing olefins such as ethylene, propylene, butene, isoprene, and pentene. Specific examples of the polyolefin resin include homopolymers such as polyethylene (PE), polypropylene (PP), polystyrene, polyacrylate, polymethacrylate, poly-1-butene, poly-1-pentene, and polymethylpentene. , Ethylene / α-olefin copolymer, vinyl alcohol ester homopolymer, polymer obtained by hydrolyzing at least a part of vinyl alcohol ester homopolymer, at least one of ethylene and propylene, and vinyl alcohol ester Polymer obtained by hydrolyzing at least part of copolymer, copolymer of at least one of ethylene and propylene and at least one of unsaturated carboxylic acid and unsaturated carboxylic acid ester, at least one of ethylene and propylene And unsaturated Copolymer obtained by metallizing at least a part of the carboxyl group of a copolymer with at least one of rubonic acid and unsaturated carboxylic acid ester, block copolymer of conjugated diene and vinyl aromatic hydrocarbon, conjugated diene and vinyl Examples thereof include hydrides of block copolymers with aromatic hydrocarbons. These may be used alone or in combination of two or more. Among these, polyethylene, polypropylene, an ethylene / α-olefin copolymer, a copolymer of at least one of ethylene and propylene, and at least one of an unsaturated carboxylic acid and an unsaturated carboxylic ester, at least of ethylene and propylene A copolymer in which at least a part of a carboxyl group of a copolymer of one side and at least one of an unsaturated carboxylic acid and an unsaturated carboxylic acid ester is metallated is preferable, particularly when heat resistance such as an engine room is required. High density polyethylene (HDPE), polypropylene, an ethylene / polypropylene copolymer, or a material containing these materials is preferably used for.

  Examples of the modifying agent for acid-modifying the polyolefin resin include at least one compound of unsaturated carboxylic acid and its derivative. Examples of the unsaturated carboxylic acid or derivative thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methylmaleic acid, methyl fumaric acid, mesaconic acid, citraconic acid, glutaconic acid, and carboxylic acids thereof. Metal salts of, methyl hydrogen maleate, methyl itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxy methacrylate Ethyl, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid, endobisic -(2,2,1) -5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, glycidyl acrylate, glycidyl methacrylate, glycidyl methacrylate Glycidyl itaconate, glycidyl citraconic acid, 5-norbornene-2,3-dicarboxylic acid and the like. These may be used alone or in combination of two or more. Of these, unsaturated dicarboxylic acids and acid anhydrides thereof are preferred, and maleic acid and maleic anhydride are particularly preferred.

  Here, the method for producing an acid-modified polyolefin resin by introducing at least one compound of unsaturated carboxylic acid and its derivative into the polyolefin resin is not particularly limited. A method of copolymerizing a resin with at least one compound of an unsaturated carboxylic acid and its derivative, or a radical initiator with at least one compound of an unsaturated carboxylic acid and its derivative as an unmodified polyolefin resin Examples include a method of grafting.

  The introduction amount (modification amount) of at least one compound (modifier) of unsaturated carboxylic acid and its derivative in the acid-modified polyolefin resin is 0.001 to olefin monomer total amount in the acid-modified polyolefin resin. It is preferably in the range of 40 mol%, particularly preferably in the range of 0.01 to 35 mol%.

  Here, the weight mixing ratio of the high amino-value polyamide-based resin and the modified polyolefin-based resin is not particularly limited as long as the polyamide is a matrix having a matrix, but polyamide-based resin / modified polyolefin-based resin = 95/5. Within the range of ˜40 / 60, particularly preferably within the range of polyamide resin / modified polyolefin resin = 80/20 to 60/40. That is, when the weight mixing ratio of the polyamide resin having a high amino value exceeds 95 (the weight mixing ratio of the modified polyolefin resin is less than 5), the interlayer adhesion is poor (the target 20 N / cm can be achieved). On the other hand, if the weight mixing ratio of the polyamide resin having a high amino value is less than 40 (the weight mixing ratio of the modified polyolefin resin is more than 60), the modified polyolefin resin becomes a morphological matrix. This is because the heat resistance tends to decrease.

  In addition to the high amino value polyamide-based resin and the modified polyolefin-based resin, the outer layer material includes a polyolefin-based resin other than the modified polyolefin-based resin (unmodified polyolefin-based resin), a plasticizer, an anti-aging agent, Flame retardants, impact resistant materials, etc. may be blended as necessary.

  Here, the low-permeability resin hose of the present invention as shown in FIG. 1 can be produced, for example, as follows. That is, an inner layer material, an intermediate layer material, and an outer layer material are prepared. Next, each material is extruded from each extruder, merged into one die, and passed through a sizing die, whereby an intermediate barrier layer 2 is formed on the outer peripheral surface of the inner layer 1, and the outer layer 3 is further formed on the outer peripheral surface. A formed low-permeability resin hose can be produced. In addition, when forming a hose in the shape of a bellows, it is also possible to produce a bellows-like hose having a predetermined size by passing the co-extruded molten tube through a corrugating machine.

  In the low permeability resin hose of the present invention thus obtained, the inner diameter of the hose is preferably in the range of 2 to 40 mm, particularly preferably in the range of 2.5 to 36 mm, and the outer diameter of the hose is in the range of 3 to 44 mm. The inside is preferable, and particularly preferably within the range of 4 to 40 mm. The thickness of the inner layer 1 is preferably in the range of 0.02 to 1.0 mm, particularly preferably in the range of 0.05 to 0.6 mm. The thickness of the intermediate barrier layer 2 is preferably in the range of 0.02 to 1.0 mm, particularly preferably in the range of 0.05 to 0.3 mm. The thickness of the outer layer 3 is preferably in the range of 0.2 to 1.5 mm, and particularly preferably in the range of 0.3 to 1.0 mm.

  Note that the low-permeability resin hose of the present invention is not limited to the three-layer structure as shown in FIG. 1. For example, the low-permeability resin hose has a two-layer structure in which the outer layer 3 is directly formed on the outer peripheral surface of the inner layer 1. The innermost layer may be provided on the inner peripheral surface of the inner layer 1 or the outermost layer may be provided on the outer peripheral surface of the outer layer 3.

  The low-permeability resin hose of the present invention is used in automobiles, transportation equipment (industrial transport vehicles such as airplanes, forklifts, excavators, cranes, railway vehicles, etc.), etc., gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen , Diesel oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied petroleum gas) and other fuel transportation hoses, or chlorofluorocarbon, alternative chlorofluorocarbon, water, carbon dioxide and other refrigerant transportation hoses used for air conditioners and radiators It is used suitably for etc. The low-permeability resin hose of the present invention is not limited to these, and fuel / refrigerant barrier products such as fuel tanks, films, sheets, joints, bottles, etc., using the material for forming the low-permeability resin hose of the present invention It is also possible to produce.

  Next, examples will be described together with comparative examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[PA6]
Ube nylon 1022B, manufactured by Ube Industries

[EVOH]
Eval EP-F101, manufactured by Kuraray

[Acid-modified PP]
Maleic anhydride modified polypropylene (Mitsui Chemicals, Admer QF500)

[PA12-a]
Grill amide L25AH (terminal amino group equivalent: 60 μeq / g) manufactured by EMS

[PA12-b]
Ubesta 3030JLX2 (terminal amino group equivalent: 31 μeq / g) manufactured by Ube Industries, Ltd.

Examples 1 and 2
The inner layer materials shown in Table 1 below were prepared. Further, the outer layer materials shown in Table 1 described below were blended in the proportions shown in the table, and kneaded at 200 ° C. using a biaxial kneader to prepare outer layer materials. Then, each material was extruded from each extruder, merged into one die, and passed through a sizing die to produce a hose (an inner diameter of 6 mm, an outer diameter of 8 mm) in which an outer layer was formed on the outer peripheral surface of the inner layer. .

[Examples 3 and 4]
An inner layer material and an intermediate barrier layer material shown in Table 1 below were prepared. Further, the outer layer materials shown in Table 1 described below were blended in the proportions shown in the table, and kneaded at 200 ° C. using a biaxial kneader to prepare outer layer materials. Then, each material is extruded from each extruder, merged into one die, and passed through a sizing die, thereby forming an intermediate barrier layer on the outer peripheral surface of the inner layer, and further forming an outer layer on the outer peripheral surface. A hose (inner diameter 6 mm, outer diameter 8 mm) was prepared.

[Comparative Examples 1 and 2]
A hose having an outer layer formed on the outer peripheral surface of the inner layer in the same manner as in Examples 1 and 2, except that PA12 containing no acid-modified PP is used instead of the outer layer material of Examples 1 and 2. The inner diameter was 6 mm and the outer diameter was 8 mm.

[Comparative Examples 3 and 4]
An intermediate barrier layer is formed on the outer peripheral surface of the inner layer in the same manner as in Examples 3 and 4, except that PA12 containing no acid-modified PP is used instead of the outer layer material of Examples 3 and 4. A hose (an inner diameter of 6 mm and an outer diameter of 8 mm) having an outer layer formed on the outer peripheral surface was prepared.

  Each characteristic was evaluated according to the following reference | standard using each hose of the Example and comparative example which were obtained in this way. These results are also shown in Table 1 below.

[Peel strength]
Each low-permeability resin hose was cut into a strip shape with a width of 10 mm to prepare a sample. The inner layer / outer layer or the intermediate barrier layer / outer layer of each sample was peeled off and sandwiched between chucks of a tensile tester, and the 180-degree peel strength (N / cm) was measured under a tensile speed of 50 mm / min. If the peel strength is 20 N / cm or more, it is considered that the interlayer adhesion is good.

  From the above results, all of the example products had high peel strength between the inner layer / outer layer or the intermediate barrier layer / outer layer, and good interlayer adhesion.

  On the other hand, since Comparative Examples 1 to 4 do not use an acid-modified polyolefin resin such as acid-modified PP as the outer layer material, the peel strength between the inner layer / outer layer or the intermediate barrier layer / outer layer is low. Adhesion was poor.

  The low-permeability resin hose of the present invention is a fuel such as gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied petroleum gas), etc. It can be suitably used for transport hoses, or refrigerant transport hoses such as chlorofluorocarbons, alternative chlorofluorocarbons, water and carbon dioxide used in air conditioners and radiators.

It is a schematic diagram which shows an example of the low-permeability resin hose of this invention.

Explanation of symbols

1 Inner layer 2 Intermediate barrier layer 3 Outer layer

Claims (3)

  A low-permeability resin hose comprising a tubular inner layer and an outer layer provided on the outer periphery thereof, wherein the inner layer is formed using a polyamide-based resin, and the outer layer is formed of a high-amino-value polyamide-based resin. And a low-permeability resin hose formed using a mixture with an acid-modified polyolefin resin.   The low-permeability resin hose according to claim 1, wherein an intermediate barrier layer formed using an ethylene-vinyl alcohol copolymer is provided between the inner layer and the outer layer.   The low permeability resin hose according to claim 1 or 2, wherein the polyamide resin having a high amino value forming the outer layer has a terminal amino group concentration of 40 µequivalent / g or more.

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