JP2015231709A - Laminated structure and molding containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost laminated structure in which interlayer adhesive properties between a polyamide-containing layer and the other layer is satisfactory, and fuel permeability is low and strength is high even if the thickness of the polyamide-containing layer is thin.SOLUTION: Provided is a laminated structure obtained by laminating at least a polyethylene layer (A) as an external layer, an adhesive layer (B) as an intermediate layer and a semi-aromatic polyamide layer (C) as an internal layer, in which the adhesive layer (B) includes a modified ethylene α-olefin copolymer obtained by graft-modifying an unsaturated carboxylic acid or a derivative of the unsaturated carboxylic acid, and in which density measured in accordance with ASTMD1505 is 0.910 to 0.935 g/cm.

Description

  The present invention relates to a laminated structure and a molded product including the same.

  Polyamide 12 (PA12) and polyamide 11 (PA11), which are excellent in flexibility, have been conventionally used in many fuel pipes for automobiles. However, in recent years, from the viewpoint of preventing environmental pollution, the regulation of transpiration of fuel gas for automobiles and the like has become strict. Therefore, the fuel pipe is required to have low fuel gas permeability. Furthermore, alcohol gasoline blended with low-boiling alcohols such as methanol and ethanol has been put into practical use from the viewpoint of saving gasoline consumption and improving performance, and conventional fuel (gasoline etc.) can be used only for fuel pipe hoses. There is also a demand for low permeability of alcohol gasoline and the like.

  In response to such demands, fuel pipe hoses and the like having an outer layer made of PA12 or PA11 and a fuel barrier layer (inner layer) made of fluororesin have been developed. Moreover, semi-aromatic resins such as polyphenylene sulfide resin (PPS); polymetaxylylene adipamide (MXD6), polyamide 6T (PA6T), and polyamide 9T (PA9T) are cheaper than fluororesins and have low fuel permeability. A fuel pipe hose having a fuel barrier layer made of a group polyamide resin; a polyester resin such as polybutylene terephthalate (PBT) or polybutylene naphthalate (PBN) has also been proposed (for example, Patent Document 1).

  Here, in the fuel pipe hose having the fuel barrier layer made of fluororesin, semi-aromatic polyamide resin, polyester resin, etc., the outer layer made of PA12 or PA11 does not necessarily have a function of reducing the fuel permeability. , Has a role to protect the fuel barrier layer, a role to prevent deterioration of the fuel piping hose due to calcium chloride as a road antifreeze agent, a role to prevent damage to the fuel piping hose due to internal pressure caused by fuel vapor, etc. . Such an outer layer is required to be reduced in cost.

  On the other hand, a fuel pipe hose having an inner layer containing a relatively inexpensive polyolefin-based resin and an outer layer containing MXD6 or the like has also been proposed (Patent Document 2). However, in the fuel pipe hose described in Patent Document 2, it is difficult to sufficiently suppress the permeation of fuel.

  A fuel pipe hose having an inner layer made of polyamide 9T (PA9T) having low fuel permeability and an outer layer made of a relatively inexpensive polyolefin-based resin has also been proposed (Patent Document 3).

Special table 2007-502726 JP-A-4-272592 JP 2006-281507 A

  However, as in Patent Document 3, in the fuel pipe hose in which the polyolefin resin layer and the semi-aromatic polyamide layer (PA9T) are laminated, the interlayer adhesion is improved, but the fuel barrier property is relatively high and relatively high. Further improvement is desired with respect to interlayer adhesion with the PA6T layer, which is a low-cost material. In addition, when the strength of the hose and the fuel swell resistance are low, the hose may be damaged by pressure from the inside of the hose. Therefore, there is a problem that it is necessary to increase the thickness of the high-strength polyamide layer and it is difficult to reduce the cost.

  The present invention has been made in view of the above circumstances. That is, the present invention provides a laminate structure in which the interlayer adhesion between the polyamide-containing layer and other layers is good, the fuel permeability is low, the strength is high, and the cost is low even if the polyamide-containing layer is thin. Provide the body.

That is, the first of the present invention relates to the following laminated structure.
[1] A laminated structure in which at least an outer layer is a polyethylene layer (A), an intermediate layer is an adhesive layer (B), and an inner layer is a semi-aromatic polyamide layer (C), and the adhesive layer (B) Includes a modified ethylene / α-olefin copolymer obtained by graft-modifying an unsaturated carboxylic acid or derivative thereof to an ethylene / α-olefin copolymer, and a density measured according to ASTM D1505 is 0.910. A laminated structure having 0.935 g / cm ³ .

[2] The polyethylene layer (A) contains an ethylene / α-olefin (co) polymer having a density measured according to ASTM D1505 of 0.925 to 0.970 g / cm ^3. ] The laminated structure as described in.
[3] The modified ethylene / α-olefin copolymer included in the adhesive layer (B) includes 0.08 to 5% by mass of the structure derived from the unsaturated carboxylic acid or a derivative thereof, [1] or [ 2].
[4] The laminated structure according to any one of [1] to [3], wherein the modified ethylene / α-olefin copolymer included in the adhesive layer (B) includes a structure derived from maleic anhydride.
[5] The polyethylene layer (A) is obtained by using a metallocene catalyst and has a melt flow rate of 0.01 to 10 g / 10 min measured in accordance with ASTM D1238 (230 ° C., 2.16 Kg). The laminated structure according to any one of [1] to [4], comprising a (co) polymer of ethylene and an α-olefin having 3 to 16 carbon atoms.

[6] The ratio of the thickness (T _c ) of the semi-aromatic polyamide layer (C) to the total thickness (Ts) of the laminated structure is 0.05 to 0.4. [1] to [5] The laminated structure according to any one of the above.
[7] The ratio of the thickness ( _Tc ) of the semi-aromatic polyamide layer (C) to the total thickness (Ts) of the laminated structure is 0.05 to 0.3. [1] to [6] The laminated structure according to any one of the above.
[8] The laminated structure according to any one of [1] to [7], further including a conductive layer containing a resin and a conductive filler in the innermost layer of the laminated structure.

[9] The semi-aromatic polyamide layer (C) has a dicarboxylic acid component in which 40 to 100 mol% is terephthalic acid with respect to the total dicarboxylic acid component, and 60 to 100 mol% with respect to the total diamine component. A semi-aromatic polyamide resin obtained by polymerizing a diamine component which is an aliphatic diamine of several 4 to 12 and a modified olefin polymer obtained by modifying an olefin polymer with a compound having a functional group. The laminated structure according to any one of [1] to [8], wherein
[10] The laminated structure according to [9], wherein the modified olefin polymer is a modified ethylene / α-olefin copolymer obtained by graft-modifying an ethylene / α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof. body.

[11] The semi-aromatic polyamide layer (C) includes a semi-aromatic polyamide resin and a modified olefin polymer obtained by modifying an olefin polymer with a compound having a functional group, and the semi-aromatic polyamide resin Are structural units derived from terephthalic acid [a], structural units derived from isophthalic acid [b], structural units derived from aliphatic dicarboxylic acid [c] having 4 to 12 carbon atoms, and 4 to 10 carbon atoms. A structural unit derived from terephthalic acid [a], a structural unit derived from terephthalic acid [a], a structural unit derived from isophthalic acid [b] from 25 to 40 mol%, an aliphatic dicarboxylic acid [ c] structural units derived from 15 to 35 mol% (provided that the total of [a], [b], and [c] is 100 mol%), the structural units derived from the terephthalic acid [a], A structural unit derived from isophthalic acid [b] The molar ratio ([a] / [b]) is 65 / 35-50 / 50, and the molar ratio between the structural unit derived from the aliphatic dicarboxylic acid [c] and the structural unit derived from the isophthalic acid [b]. The ratio ([c] / [b]) is 30 / 70-50 / 50, and the heat of fusion (ΔH) obtained by differential scanning calorimetry (DSC) is 20-40 mJ / mg, which is the limit. The laminated structure according to any one of [1] to [8], wherein the viscosity [η] is 0.7 to 1.6 dl / g.
[12] The laminated structure according to [11], wherein the modified olefin polymer is a modified ethylene / α-olefin copolymer obtained by graft-modifying an ethylene / α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof. body.

2nd of this invention is related with the following molded articles.
[13] A molded product comprising the laminated structure according to any one of [1] to [12].
[14] The molded product according to [13], which is selected from the group consisting of a hose and a tube.
[15] The molded product according to [13] or [14], which is a tube for fuel piping.

  The laminated structure of the present invention has excellent interlayer adhesion, low fuel permeability, high strength, and further cost reduction.

It is a schematic sectional drawing which shows an example of the molded article which consists of a laminated structure of this invention.

1. Laminated structure The laminated structure of the present invention is a structure including at least three layers of an outer layer, an intermediate layer, and an inner layer, and the laminated structure includes a hose and a tube for conveying gas and liquid; It is applied to bottles and tanks for storing gas and liquid. In particular, since the laminated structure of the present invention has low fuel permeability for automobiles, it is preferably used for various molded products for fuel storage or fuel transportation. Here, the fuel refers to various fuels such as gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, biodiesel fuel, dimethyl ether, LPG, CNG and the like.

  FIG. 1 is a schematic cross-sectional view showing an example of a molded product (tube for fuel piping) comprising the laminated structure of the present invention. The outer layer 1 in the laminated structure 100 of the present invention is a layer arranged on the outer surface side of various molded products, and serves to protect the inner layer 3 of the laminated structure 100 from the external environment and to maintain strength. Is a layer. On the other hand, the inner layer 3 is a layer arranged on the inner side of various molded products, and is a layer for suppressing gas or liquid from leaking to the outside or evaporating from the inside of the various molded products. . The intermediate layer 2 is a layer for bonding them. In the laminated structure 100 of the present invention, the outer layer 1 is a polyethylene layer (A), the intermediate layer 2 is an adhesive layer (B), and the inner layer 3 is a semi-aromatic polyamide layer (C).

  As described above, simply laminating an outer layer made of polyolefin and an inner layer made of semi-aromatic polyamide may result in low interlayer adhesion of the laminated structure, for example, when filling a molded product with fuel oil or the like In addition, the adhesive strength between the polyethylene layer and the semi-aromatic polyamide layer may be reduced, resulting in delamination. As a result, functions such as fuel barrier properties cannot be maintained, and reliability as a molded product may be lacking.

In contrast, in the laminated structure of the present invention, the polyethylene layer (A) and the semi-aromatic polyamide layer (C) are firmly bonded by the adhesive layer (B), and the reliability of the laminated structure is improved. Remarkably high. The adhesive layer (B) of the laminated structure contains a modified ethylene / α-olefin copolymer, and the density of the adhesive layer (B) is 0.910 to 0.935 g / cm ³ . Therefore, interlayer adhesiveness with a polyethylene layer (A) and a semi-aromatic polyamide layer (C) is high.

1-1. Polyethylene layer (A)
The polyethylene layer (A) includes a polyethylene-based resin whose main component is a constituent component derived from ethylene. The polyethylene layer (A) may contain other components as required in addition to the polyethylene-based resin. However, it is preferable that a polyethylene-type resin is contained 60 mass% or more with respect to the total mass of a polyethylene layer (A), More preferably, it is 80 mass% or more. The intensity | strength of a polyethylene layer (A) increases that the quantity of a polyethylene-type resin is 60 mass% or more, and also interlayer adhesiveness with an adhesive bond layer (B) increases.

  Examples of the polyethylene resin contained in the polyethylene layer (A) include ethylene / α-olefin (co) polymers such as high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene; -Ethylene / unsaturated carboxylic acid copolymers such as vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer; ethylene / unsaturated carboxylic acid ester copolymer; ionomer resin, etc. included. In the polyethylene-based resin, the structural unit derived from ethylene is preferably contained in an amount of 80 mol% or more, more preferably 90 mol% or more based on the total amount (mol) of the structural units constituting the ethylene-based resin.

  The polyethylene resin contained in the polyethylene layer (A) is preferably an ethylene / α-olefin (co) polymer from the viewpoint of moldability and the like. The ethylene / α-olefin (co) polymer includes an ethylene homopolymer or a copolymer of ethylene and an α-olefin. In the ethylene / α-olefin (co) polymer, the structural unit derived from ethylene is 90 to 99.99 mol with respect to the number (mole number) of structural units constituting the ethylene / α-olefin (co) polymer. %, More preferably 94-99.99 mol%.

  The number of carbon atoms of the α-olefin copolymerized with ethylene is not particularly limited, but is preferably 3 to 16, more preferably 3 to 12. Specific examples of the α-olefin having 3 to 16 carbon atoms include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and the like.

  Here, the melt flow rate measured according to ASTM D1238 (230 ° C., 2.16 kg load) of the ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is 0.01 to 10 g / It is preferable that it is 10 minutes, More preferably, it is 0.01-5 g / 10min, More preferably, it is 0.05-1 g / 10min. When the melt flow rate of the ethylene / α-olefin (co) polymer is in the above range, the polyethylene / layer of the ethylene / α-olefin (co) polymer has high fluidity and a uniform thickness when the laminated structure is produced. (A) is easily obtained. The melt flow rate of the ethylene / α-olefin (co) polymer is adjusted by the molecular weight or the like.

Here, the density of the ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is preferably 0.925 to 0.970 g / cm ³ , and preferably 0.925 to 0.960 g / cm 3. ³ is more preferable, and 0.935 to 0.955 g / cm ³ is still more preferable. The density of the ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is measured in accordance with ASTM D1505. When the density of the ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is 0.970 g / cm ³ or less, the flexibility of the laminated structure tends to increase. On the other hand, when the density of the ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is 0.925 g / cm ³ or more, even if the polyethylene layer (A) is used for a long time, It is difficult to be affected by swelling caused by vaporized fuel, and strength and pressure resistance are likely to increase. The density of the polyethylene layer (A) is adjusted by the type of polyethylene resin, the preparation conditions thereof, and the like.

  The ethylene / α-olefin (co) polymer contained in the polyethylene layer (A) is preferably prepared using a metallocene catalyst. An ethylene / α-olefin (co) polymer obtained using a metallocene catalyst has a small molecular weight distribution and therefore has a low content of low molecular weight components. Therefore, the polyethylene layer (A) obtained by molding the ethylene / α-olefin (co) polymer has higher strength, toughness, and fuel swelling resistance than polyethylene prepared with a catalyst other than a metallocene catalyst. Therefore, the strength of the laminated structure and the reliability during use are significantly increased. As a result, even if the thickness of the semi-aromatic polyamide layer (C) of the laminated structure is thin, the pressure resistance of the laminated structure can be increased. Moreover, since the thickness of a semi-aromatic polyamide layer (C) can be made thin, the cost of a laminated structure is also reduced.

  The polyethylene layer (A) may contain various additives such as fillers, stabilizers, activators, antistatic agents, flame retardants, foaming agents, pigments, dyes, and the like as necessary.

1-2. Adhesive layer (B)
The adhesive layer (B) includes a modified ethylene / α-olefin copolymer obtained by graft-modifying an ethylene / α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof. The adhesive layer (B) may contain other components as necessary, but the modified ethylene / α-olefin copolymer is 60% by mass or more based on the total mass of the adhesive layer (B). It is preferably contained, more preferably 80% by mass or more. When the amount of the modified ethylene / α-olefin copolymer is 60% by mass or more, the strength of the adhesive layer (B), the polyethylene layer (A), and the semi-aromatic polyamide layer (C) increases.

  Here, the ethylene / α-olefin copolymer modified with an unsaturated carboxylic acid or a derivative thereof may be a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. The α-olefin preferably has 3 to 10 carbon atoms. Examples of the α-olefin include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and the like.

  The unsaturated carboxylic acid for graft-modifying the ethylene / α-olefin polymer is not particularly limited. For example, (meth) acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, Unsaturated carboxylic acids such as isocrotonic acid and nadic acid (endocis-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid); or its acid halides, amides, imides, anhydrides, esters, etc. It may be a derivative of Among these, unsaturated dicarboxylic acid or an anhydride thereof is preferable, maleic acid, nadic acid or an acid anhydride thereof is more preferable, and maleic anhydride is particularly preferable.

The modified ethylene / α-olefin copolymer may contain 0.08 to 5% by mass of the structure derived from the unsaturated carboxylic acid or derivative thereof relative to the mass of the modified ethylene / α-olefin copolymer. More preferably, it is 0.08-3 mass%, More preferably, it is 0.08-1 mass%. When the structure derived from the unsaturated carboxylic acid or its derivative is included in the above range, the adhesiveness of the adhesive layer (B) is likely to increase. The ratio of the structure derived from the unsaturated carboxylic acid or derivative thereof contained in the modified ethylene / α-olefin copolymer can be specified by a known means such as ¹³ C-NMR measurement or ¹ H-NMR measurement. Specific conditions for NMR measurement include the following conditions.

^In the case of ¹ H-NMR measurement, an ECX400 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd. is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg / 0.6 mL, the measurement temperature is 120 ° C., the observation nucleus Is 1H (400 MHz), the sequence is a single pulse, the pulse width is 5.12 μs (45 ° pulse), the repetition time is 7.0 seconds, and the number of integration is 500 times or more. The standard chemical shift is 0 ppm for tetramethylsilane hydrogen. For example, the same result can be obtained by setting the peak derived from residual hydrogen in deuterated orthodichlorobenzene to 7.10 ppm and setting the standard value for chemical shift. be able to. A peak such as ¹ H derived from the functional group-containing compound can be assigned by a conventional method.

^In the case of ¹³ C-NMR measurement, an ECP500 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd. is used as a measurement apparatus, a mixed solvent of orthodichlorobenzene / heavy benzene (80/20 vol%), a measurement temperature is 120 ° C., The observation nuclei are conditions of 13C (125 MHz), single pulse proton decoupling, 45 ° pulse, repetition time of 5.5 seconds, integration number of 10,000 times or more, and 27.50 ppm as a reference value for chemical shift. Assignment of various signals is performed based on a conventional method, and quantification can be performed based on an integrated value of signal intensity.

  The modified ethylene / α-olefin copolymer is obtained by reacting an unsaturated carboxylic acid or a derivative thereof in a state where the ethylene / α-olefin copolymer is melted. The reaction (graft modification) of the ethylene / α-olefin copolymer with the unsaturated carboxylic acid or derivative thereof can be carried out by a known method, for example, by reacting them in the presence of an organic peroxide. A modified ethylene / α-olefin copolymer is obtained. Further, the graft modification is preferably performed in the absence of a solvent from the viewpoint of the adhesiveness of the adhesive layer (B) and the like.

Here, the density of the adhesive layer (B) is 0.910 to 0.935 g / cm ³ , preferably 0.920 to 0.935 g / cm ³ . The density is measured according to ASTM D1505. If the density of the adhesive layer (B) is at 0.910 g / cm ³ or more, the strength is likely to increase the adhesive layer (B), If it is 0.935 g / cm ³ or less, and the adhesive layer (B) Adhesion with the semi-aromatic polyamide layer (C) tends to increase. That is, when the density of the adhesive layer (B) is in the above range, the balance between the strength and adhesiveness of the adhesive layer (B) is excellent, and the adhesive layer (B) and the semi-aromatic polyamide layer (C) Adhesiveness increases. The density of the adhesive layer (B) is adjusted by the kind of α-olefin in the above-mentioned modified ethylene / α-olefin copolymer, the amount of unsaturated carboxylic acid or its derivative contained in the modified ethylene / α-olefin, and the like. Is done.

  Moreover, it is preferable that the ratio of the thickness (Tb) of an adhesive bond layer (B) is 0.005-0.1 with respect to the thickness (Ts) of a laminated structure, More preferably, it is 0.001-0. 06. When the thickness ratio of the adhesive layer (B) is 0.005 or more, the interlayer adhesive force of each layer constituting the laminated structure is likely to increase. On the other hand, when the thickness of the adhesive layer (B) is 0.1 or less, the thickness of the polyethylene layer (A) or the semi-aromatic polyamide layer (C) is relatively thick, and the pressure resistance of the laminated structure is increased. The fuel permeation resistance of the laminated structure is increased. The specific thickness of the adhesive layer (B) is preferably 5 to 100 μm, more preferably 10 to 60 μm, and still more preferably 15 to 40 μm.

1-3. Semi-aromatic polyamide layer (C)
The semi-aromatic polyamide layer (C) includes a semi-aromatic polyamide resin. The semi-aromatic polyamide resin is a polyamide containing an aliphatic-derived structural unit and an aliphatic-derived structural unit. When the semi-aromatic polyamide layer (C) is included in the laminated structure, the permeability of the laminated structure is reduced.

  The semi-aromatic polyamide layer (C) preferably contains 50% by mass or more, more preferably 60 to 97% by mass of the semi-aromatic polyamide resin with respect to the total mass of the semi-aromatic polyamide layer (C). More preferably, it is 75-95 mass%. When the semiaromatic polyamide layer (C) contains 50% by mass or more of the semiaromatic polyamide resin, the fuel permeation resistance of the laminated structure is increased.

  On the other hand, the semi-aromatic polyamide layer (C) may further include a modified olefin polymer obtained by modifying an olefin polymer with a compound having a functional group (functional group-containing compound). If the semi-aromatic polyamide layer (C) contains a modified olefin polymer, the impact strength of the semi-aromatic polyamide layer (C) is likely to increase and flexibility can be imparted. It is preferable that 7-28 mass% of modified | denatured olefin polymers are contained with respect to the total mass of a semi-aromatic polyamide layer (C), More preferably, it is 5-25 mass%.

  Here, the semi-aromatic polyamide resin contained in the semi-aromatic polyamide layer (C) is obtained by polymerizing a dicarboxylic acid component and a diamine component. It is preferable that 40-100 mol% of terephthalic acid [a] is contained in a dicarboxylic acid component with respect to all the dicarboxylic acid components. Moreover, it is preferable that 60-100 mol% of C4-C12 aliphatic diamine [d] is contained in a diamine component with respect to all the diamine components.

  On the other hand, the semi-aromatic polyamide resin has a structural unit derived from terephthalic acid [a] represented by the following formula, a structural unit derived from isophthalic acid [b] represented by the following formula, and 4 to 10 carbon atoms. It is also preferable that a structural unit derived from aliphatic dicarboxylic acid [c] and a structural unit derived from aliphatic diamine [d] having 4 to 12 carbon atoms are included.

Structural unit derived from terephthalic acid [a] Structural unit derived from isophthalic acid [b]

  When the total of the structural unit derived from terephthalic acid [a], the structural unit derived from isophthalic acid [b], and the structural unit derived from [c] contained in the semi-aromatic polyamide resin is 100 mol%, terephthalic acid The content of the structural unit derived from the acid [a] is preferably 35 to 50 mol%, and the content of the structural unit derived from the isophthalic acid [b] is preferably 25 to 40 mol%, more preferably 30 to 30 mol%. The content of the structural unit derived from the aliphatic dicarboxylic acid [c] having 4 to 10 carbon atoms is preferably 15 to 35 mol%, more preferably 20 to 30 mol%.

  Examples of the aliphatic dicarboxylic acid [c] having 4 to 10 carbon atoms include adipic acid (6 carbon atoms), suberic acid (8 carbon atoms), azelaic acid (9 carbon atoms), sebacic acid (carbon Chain aliphatic dicarboxylic acids such as those having 10 atoms) are included. The aliphatic dicarboxylic acid [c] is particularly preferably adipic acid from the viewpoints of cost, strength of the semi-aromatic polyamide layer (C), and the like.

  In addition, the semiaromatic polyamide resin may contain a structural unit derived from a dicarboxylic acid other than the dicarboxylic acids [a] to [c] (a structural unit derived from another carboxylic acid). However, the number of moles of structural units derived from other dicarboxylic acids is preferably 5% or less with respect to the total number of moles of [a] to [c]. Examples of other dicarboxylic acids include aromatic dicarboxylic acids such as 2-methylterephthalic acid and naphthalenedicarboxylic acid, furandicarboxylic acids such as 2,5-furandicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3- Examples include alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids having 11 or more phthalic carbon atoms.

  The semiaromatic polyamide resin preferably contains a structural unit derived from an aliphatic diamine [d] having 4 to 12 carbon atoms as a structural unit derived from diamine. The aliphatic diamine [d] may be a linear aliphatic diamine or a chain aliphatic diamine having a side chain. Examples of the aliphatic diamine [D] include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane and 1,10-diamino. Linear aliphatic diamines such as decane, 1,11-diaminoundecane, 1,12-diaminododecane; 2-methyl-1,5-diaminopetane, 2-methyl-1,6-diaminohexane, 2-methyl-1 , 7-diaminoheptane, 2-methyl-1,8-diaminooctane, 2-methyl-1,9-diaminononane, 2-methyl-1,10-diaminodecane, 2-methyl-1,11-diaminoundecane, etc. A chain aliphatic diamine having a side chain is included.

  The aliphatic diamine [d] is preferably a diamine having 6 to 9 carbon atoms, more preferably hexamethylene diamine (6 carbon atoms) or nonane diamine (9 carbon atoms).

  The semi-aromatic polyamide resin may contain a structural unit derived from diamine other than the aliphatic diamine [d], but the number of moles thereof is 10% or less with respect to the number of moles of [d]. Is preferred. Examples of other diamines include aromatic diamines such as metaxylenediamine, and alicyclic diamines such as 1,4-cyclohexanediamine and 1,3-cyclohexanediamine.

  Here, the melt tension at the “melting end temperature (T) +10 (° C.)” of the semi-aromatic polyamide resin contained in the semi-aromatic polyamide layer (C) is preferably 3 to 30 mN, and preferably 5 to 25 mN. It is more preferable that The melt tension of the semi-aromatic polyamide resin is “CAPILROGRAPH 1B” manufactured by Toyo Seiki, with a capillary diameter of 1.0 mmφ, a capillary length of 20 mm, a winding speed of 10 m / min, and a melting end temperature (T) of + 10 ° C. Measured. When the melt tension (melt tension: mN) is in the above range, the shape-retaining property of the semi-aromatic polyamide layer (C) obtained by molding the semi-aromatic polyamide resin can be improved, and the laminated structure is produced. Sometimes drawdown is unlikely to occur. A method for measuring the melting end temperature (T) will be described later.

  The melt tension of the semi-aromatic polyamide resin is mainly adjusted by the molecular weight and the ratio of the structural units derived from [a] to [c] contained in the semi-aromatic polyamide resin.

  In the semi-aromatic polyamide resin, the molar ratio ([a] / [b]) between the structural unit derived from [a] and the structural unit derived from [b] is preferably 65/35 to 50/50. While terephthalic acid [a] imparts crystallinity to the semi-aromatic polyamide resin to increase the heat resistance of the semi-aromatic polyamide layer (C), it is difficult to increase the melt tension of the semi-aromatic polyamide resin. On the other hand, it is considered that isophthalic acid [b] can increase the melt tension of the semi-aromatic polyamide resin while maintaining the heat resistance of the semi-aromatic polyamide layer (C).

  In the semi-aromatic polyamide, the molar ratio ([c] / [b]) between the structural unit derived from [c] and the structural unit derived from [b] is preferably 30/70 to 50/50. Aliphatic dicarboxylic acid [c] can impart non-crystalline properties to the semi-aromatic polyamide resin (decrease melting end temperature (T)) and improve molding processability. Hard to increase melt tension. On the other hand, it is considered that isophthalic acid [b] can increase the melt tension of the semi-aromatic polyamide resin while maintaining the heat resistance of the semi-aromatic polyamide resin.

  That is, when the ratio of the structural units derived from [a] to [c] in the semi-aromatic polyamide resin is in the above range, the melt tension of the semi-aromatic polyamide resin is increased. Here, PA6T (polyamide obtained from terephthalic acid and hexamethylenediamine) and PA66 (polyamide obtained from adipic acid and hexamethylenediamine) are known to have low melt tension. Since both PA6T and PA66 contain dicarboxylic acid or diamine having high linearity as constituent components, they are highly rigid and have little entanglement between polymer chains. Therefore, it is presumed that the tension during melting is relatively low.

  On the other hand, the structural units derived from [a] to [c] described above are contained in a specific range, in particular, the molar ratio ([a] / [b]) and the molar ratio ([c] / [b]). It is considered that the tension at the time of melting is increased by appropriately setting. That is, isophthalic acid [b] has a bent structure rather than a linear shape. Therefore, the rigidity of the polymer chain of the semi-aromatic polyamide resin is relaxed, and the polymer chains are easily entangled with each other. And it is guessed that the tension | tensile_strength at the time of the melt | dissolution of a semi-aromatic polyamide resin increases.

  Here, the intrinsic viscosity [η] of the semi-aromatic polyamide resin contained in the semi-aromatic polyamide layer (C) is preferably 0.7 to 1.6 dl / g, and 0.8 to 1.2 dl / g. It is more preferable that The intrinsic viscosity [η] is measured in a temperature of 25 ° C. and 96.5% sulfuric acid. When the intrinsic viscosity [η] is 0.7 dl / g or more, the mechanical strength of the resulting semi-aromatic polyamide layer (C) increases, while the above-described melt tension tends to fall within a desired range. In addition, when the intrinsic viscosity [η] is 1.6 dl / g or less, the balance between fluidity and mechanical strength during molding is excellent. In order to adjust the intrinsic viscosity [η] of the semi-aromatic polyamide resin within the above range, for example, it is preferable to mix a molecular weight regulator or the like in the reaction system to react the dicarboxylic acid component and the diamine component. As the molecular weight modifier, monocarboxylic acid and monoamine can be used.

  The heat of fusion (ΔH) of the semi-aromatic polyamide resin is preferably 20 to 40 mJ / mg, and more preferably 20 to 35 mJ / mg. The heat of fusion is an indicator of the crystallinity of the polyamide, and the higher the heat of fusion, the higher the crystallinity, and the lower the heat of fusion, the lower the crystallinity. Although the semi-aromatic polyamide resin contains a structural unit derived from terephthalic acid [a] and has a certain crystallinity, the structural units derived from dicarboxylic acids [a] to [c] are arranged as randomly as possible. It is preferable. If the structural units derived from dicarboxylic acids [a] to [c] are not randomly arranged and the structural units derived from terephthalic acid [a] are arranged as blocks, the crystallinity of the semi-aromatic polyamide resin is excessively increased. As a result, the heat of fusion (ΔH) becomes higher than 40 mJ / mg.

  Examples of the monocarboxylic acid used as the molecular weight modifier include aliphatic monocarboxylic acids having 2 to 30 carbon atoms, aromatic monocarboxylic acids and alicyclic monocarboxylic acids. In addition, the aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent in the cyclic structure portion. For example, aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid. be able to. Examples of aromatic monocarboxylic acids include benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid. Examples of alicyclic monocarboxylic acids include cyclohexanecarboxylic acid. Can be mentioned.

  The molecular weight modifier is added to a reaction system in which a dicarboxylic acid and a diamine are reacted to form a polyamide, and is usually 0 to 0.07 mol, preferably 0 to 0.0. It is preferably added in an amount of 05 mol. By using the molecular weight adjusting agent in such an amount, at least a part of the molecular weight adjusting agent is incorporated into the polyamide, whereby the molecular weight of the polyamide, that is, the intrinsic viscosity [η] is adjusted within a desired range.

  It is preferable that melting | fusing point (Tm) calculated | required by differential scanning calorimetry (DSC) of a semi-aromatic polyamide resin is 230 degreeC or more. A sample of semi-aromatic polyamide resin was heated using a DSC7 manufactured by PerkinElmer, temporarily held at 320 ° C. for 5 minutes, then cooled to 23 ° C. at a rate of 10 ° C./minute, and then increased at 10 ° C./minute. Warm up. The endothermic peak based on melting at this time may be the melting point (Tm) of the polyamide. However, the temperature corresponding to the peak top of the endothermic peak observed in the differential scanning calorimetry may not be clear.

  The melting end temperature (T) determined by differential scanning calorimetry (DSC) of the semi-aromatic polyamide resin is preferably 250 to 300 ° C. The melting end temperature (T) refers to the temperature at which the endotherm due to melting disappears in differential scanning calorimetry similar to the measurement of the melting point. Specifically, it refers to the temperature at which the endothermic peak observed in differential scanning calorimetry returns to the baseline. The melting end temperature (T) can be lowered by arranging the structural units derived from [a] to [c] in the semi-aromatic polyamide resin as randomly as possible.

  Moreover, it is preferable that the melt flow rate (T + 10 degreeC, 2.16 kg) of a semi-aromatic polyamide resin is 1-50 g / 10min. The melt flow rate of the semi-aromatic polyamide resin can be measured according to ASTM D1238 procedure B.

  The aforementioned semi-aromatic polyamide resin is prepared based on a known production method as a conventional method for producing a semi-aromatic polyamide resin. For example, dicarboxylic acids [a] to [c] and diamine [d] can be produced by polycondensation in a homogeneous solution. More specifically, a low-order condensate is obtained by heating dicarboxylic acid and diamine in the presence of a catalyst as described in WO 03/085029, and then this low-order condensate. It can be produced by polycondensation by applying shear stress to the melt.

  On the other hand, the modified olefin polymer contained in the semi-aromatic polyamide layer (C) may be obtained by modifying an olefin polymer with a compound having a functional group (functional group-containing compound). The functional group preferably contains a hetero atom, and examples of the functional group include a carboxylic acid group, a carboxylic anhydride group, an ester group, an ether group, an aldehyde group, and a ketone group.

  On the other hand, examples of the olefin polymer include known polymers such as an ethylene polymer, a propylene polymer, a butene polymer, and a copolymer of these olefins. A particularly preferred olefin polymer is a copolymer of ethylene and an olefin having 3 or more carbon atoms (ethylene / α-olefin copolymer).

  Other olefins to be polymerized with ethylene may be, for example, α-olefins having 3 to 10 carbon atoms such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. Specific examples of the ethylene / α-olefin copolymer include an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, 4-methyl-1-pentene copolymer and the like are included. Among these, an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and an ethylene / 1-octene copolymer are preferable.

  The ethylene / α-olefin copolymer preferably contains 70 to 99.5 mol% of structural units derived from ethylene based on the total amount of structural units constituting the ethylene / α-olefin copolymer. Preferably it is 80-99 mol%. On the other hand, the structural unit derived from the α-olefin is preferably contained in an amount of 0.5 to 30 mol%, more preferably 1 to 20 mol based on the total amount of the structural units constituting the ethylene / α-olefin copolymer. %.

  The melt flow rate (MFR) at 190 ° C. under a load of 2.16 kg measured according to ASTM D1238 of the ethylene / α-olefin copolymer is preferably 0.01 to 20 g / 10 min, more preferably. Is 0.05 to 20 g / 10 min.

  The method for producing the ethylene / α-olefin copolymer is not particularly limited. For example, a transition metal catalyst such as titanium (Ti), vanadium (V), chromium (Cr), or zirconium (Zr) is used. And can be prepared by a known method. More specifically, ethylene is copolymerized with one or more α-olefins having 3 to 10 carbon atoms in the presence of a Ziegler catalyst or a metallocene catalyst composed of a V compound and an organoaluminum compound. The method of manufacturing can be illustrated. In particular, a production method using a metallocene catalyst is suitable.

  The functional group-containing compound that modifies the olefin polymer is not particularly limited, but is preferably an unsaturated carboxylic acid or a derivative thereof. Specific examples of unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, nadic acid (endocis) -Unsaturated carboxylic acids such as bicyclo [2,2,1] hept-5-ene-2,3-dicarboxylic acid) and derivatives thereof such as acid halides, amides, imides, acid anhydrides, esters, etc. It is done. Among these, unsaturated dicarboxylic acids or acid anhydrides thereof are preferable, and maleic acid, nadic acid, or acid anhydrides thereof are particularly preferable.

  A particularly preferred compound is maleic anhydride. Maleic anhydride has a relatively high reactivity with the olefinic polymer before modification, is unlikely to cause polymerization between maleic anhydrides, and tends to be stable as a basic structure. For this reason, there are various advantages such as obtaining a modified olefin polymer having a stable quality.

  The modified olefin polymer is obtained, for example, by graft-modifying an olefin polymer with a functional group-containing compound. Hereinafter, an ethylene / α-olefin copolymer will be described with an example of graft modification with an unsaturated carboxylic acid or a derivative thereof. The graft modification of the ethylene / α-olefin copolymer can be carried out by a known method. For example, an ethylene / α-olefin copolymer is dissolved in an organic solvent, and an unsaturated carboxylic acid or a derivative thereof and a radical initiator are added to the obtained solution, and the temperature is usually 60 to 350 ° C., preferably 80 to 190 ° C. The method of making it react at temperature for 0.5 to 15 hours, Preferably it is 1 to 10 hours can be illustrated.

  The organic solvent for dissolving the ethylene / α-olefin copolymer is not particularly limited, but aromatic hydrocarbon solvents such as benzene, toluene and xylene; aliphatic hydrocarbon solvents such as pentane, hexane and heptane, etc. Can be mentioned.

  Further, as another graft modification method of ethylene / α-olefin copolymer, ethylene / α-olefin copolymer and unsaturated carboxylic acid or derivative thereof are preferably used in an extruder or the like in the absence of a solvent. The method of making it react is mentioned. The reaction conditions in this case are such that the reaction temperature is usually not lower than the melting point of the ethylene / α-olefin copolymer, specifically 100 to 350 ° C. The reaction time can usually be 0.5 to 10 minutes.

  In order to efficiently carry out graft modification reaction of a compound having a functional group such as an unsaturated carboxylic acid on the ethylene / α-olefin copolymer, it is preferable to perform a modification reaction in the presence of a radical initiator. Examples of radical initiators include organic peroxides, organic peroxides such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl 14 peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (peroxide benzoate) Hexin-3,1,4-bis (t-butylperoxyisopropyl) benzene, lauroyl peroxide, t-butylperacetate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2, 5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylperbenzoate, t-butylperphenylacetate, t-butylperisobutyrate, t-butylper-sec-octoate, t-butylper Pivalate, cumyl perpivalate and t Butyl peroxide diethyl acetate; azo compounds such as azobisisobutyronitrile, dimethyl azoisobutyrate is used. Among these, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (t Dialkyl peroxides such as -butylperoxy) hexane and 1,4-bis (t-butylperoxyisopropyl) benzene are preferred. The radical initiator is usually used at a ratio of 0.001 to 1 part by mass with respect to 100 parts by mass of the ethylene / α-olefin copolymer before modification.

The modified olefin polymer preferably has a density of 0.80 to 0.95 g / cm ³ , more preferably 0.85 to 0.90 g / cm ³ .

  Further, the intrinsic viscosity [η] of the modified olefin polymer measured in a 135 ° C. decalin (decahydronaphthalene) solution is preferably 0.5 to 4.0 dl / g, more preferably 1.0. It is -3dl / g, More preferably, it is 1.5-3dl / g. If [η] is within the above range, the strength of the semi-aromatic polyamide layer tends to increase.

  The intrinsic viscosity [η] in decalin at 135 ° C. of the modified olefin polymer is measured as follows based on a conventional method. 20 mg of a sample is dissolved in 15 ml of decalin, and the specific viscosity (ηsp) is measured in an atmosphere of 135 ° C. using an Ubbelohde viscometer. After adding 5 ml of decalin to the decalin solution and diluting, the same specific viscosity is measured. Based on the measurement result obtained by repeating this dilution operation and viscosity measurement twice more, the “ηsp / C” value when the concentration (: C) is extrapolated to zero is defined as the intrinsic viscosity [η].

  The modified olefin polymer contains 0.3 to 1.5 mass% of a structure derived from the functional group-containing compound with respect to 100 mass% of the modified olefin polymer, and more preferably 0.4 to 1. It is contained at 1% by mass. If the structure derived from the functional group-containing compound is too small, the effect of improving the toughness of the semi-aromatic polyamide layer (C) may be low.

The amount of the structure derived from the functional group-containing compound contained in the modified olefin polymer is determined by the charge ratio when the olefin polymer before modification and the compound having a functional group are reacted, ¹³ C-NMR measurement or ¹ H -It can be specified by known means such as NMR measurement. Specific NMR measurement conditions are the same as those for measurement of the structure derived from the unsaturated carboxylic acid or derivative thereof contained in the modified ethylene / α-olefin (co) polymer contained in the adhesive layer (B). It can be.

  Here, the melt tension of the mixture of the semi-aromatic polyamide resin and the modified olefin polymer is preferably 20 to 90 mN, and more preferably 30 to 70 mN. The melt tension of the mixture means the melt tension at the “melting end temperature (T) +10 (° C.)” of the aforementioned semi-aromatic polyamide resin. The melt tension of the mixture is measured at a capillary diameter of 1.0 mmφ, a capillary length of 20 mm, a winding speed of 10 m / min, and a melting end temperature (T) + 10 ° C., using “CAPILOGRAPH 1B” manufactured by Toyo Seiki.

  The melt flow rate of the mixture of the semi-aromatic polyamide resin and the modified olefin polymer is preferably 0.1 to 20 g / 10 minutes. The melt flow rate of the mixture means a melt flow rate (T + 10 ° C., 2.16 kg) with a load of 5 kg, “at the melting end temperature (T) +10 (° C.)” of the semi-aromatic polyamide resin contained therein. The melt flow rate of the mixture can be measured in accordance with ASTM D1238 procedure B.

  The flexural modulus of the mixture of the semi-aromatic polyamide resin and the modified olefin polymer is preferably 400 to 2100 MPa, and more preferably 800 to 2000 MPa. Moreover, it is preferable that the bending strength of the said mixture is 40-200 Ma, and it is more preferable that it is 60-150 MPa.

The flexural modulus and flexural strength of the mixture of the semi-aromatic polyamide resin and the modified olefin polymer were as follows. Test pieces molded using an injection molding machine under the following conditions (length 64 mm, width 6 mm, thickness 0) .8 mm) flexural modulus and flexural strength.
Molding machine: Sodick Plustech Co., Ltd. Tupar TR40S3A
Molding machine cylinder temperature: melting end temperature (T) + 10 ° C., mold temperature: 40 ° C.

  The molded test piece is allowed to stand for 24 hours in a nitrogen atmosphere at a temperature of 23 ° C., and then treated in an oven at 150 ° C. for 2 hours. Next, a bending test is performed in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50% with a bending tester: AB5 manufactured by NTSCO, span of 26 mm, and a bending speed of 5 mm / min, and the flexural modulus and strength are measured.

  The semi-aromatic polyamide resin and the modified olefin polymer are mixed by mixing the semi-aromatic polyamide resin and the modified olefin polymer by a known method such as a Henschel mixer, a V blender, a ribbon blender, or a tumbler blender. It can be carried out by a method, or a method of further granulating or pulverizing after mixing with a single screw extruder, a multi-screw extruder, a kneader, a Banbury mixer or the like after mixing.

  The semi-aromatic polyamide layer (C) may contain an optional additive as necessary within the range not impairing the effects of the invention, together with the semi-aromatic polyamide resin and the modified olefin polymer. Examples of optional additives include antioxidants (phenols, amines, sulfurs, phosphorus, etc.), fillers (clay, silica, alumina, talc, kaolin, quartz, mica, graphite, etc.), heat resistant stability Agents (lactone compounds, vitamin Es, hydroquinones, copper halides, iodine compounds, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), other polymers (Olefins such as polyolefins, ethylene / propylene copolymer, ethylene / 1-butene copolymer, olefin copolymers such as propylene / 1-butene copolymer, polystyrene, polyamide, polycarbonate, polyacetal, poly Sulphone, polyphenylene oxide, fluorine resin, silicone resin LCP, etc.), flame retardants (bromine, chlorine, phosphorus, antimony, inorganic, etc.), fluorescent brighteners, plasticizers, thickeners, antistatic agents, release agents, pigments, crystal nucleating agents, various Known compounding agents are included.

  The amount of the optional additive contained in the semi-aromatic polyamide layer (C) varies depending on the type of the component, but when the total of the semi-aromatic polyamide resin and the modified olefin polymer is 100% by mass, The content is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and still more preferably 0 to 1% by mass.

  Here, the ratio of the thickness (Tc) of the semi-aromatic polyamide layer (C) is preferably 0.05 to 0.4, more preferably 0.05 to the thickness (Ts) of the laminated structure. ~ 0.3. When the ratio of the thickness of the semi-aromatic polyamide layer (C) is 0.05 or more, the fuel permeability of the laminated structure is reduced. On the other hand, when the thickness ratio of the semi-aromatic polyamide layer (C) is 0.4 or less, the cost of the laminated structure can be easily reduced. Here, the specific thickness of the semi-aromatic polyamide layer (C) is preferably 10 to 400 μm, and more preferably 50 to 300 μm.

1-4. Other Layers The laminated structure of the present invention includes layers other than the above-mentioned polyethylene layer (A), adhesive layer (B), and semi-aromatic polyamide layer (C) as long as the effects of the present invention are not impaired. May be. For example, a conductive layer having conductivity may be separately stacked on the innermost layer of the stacked structure.

  If the innermost layer of the laminated structure is insulative, static electricity may accumulate in the laminated structure when liquid fuel or the like flows inside a molded product (for example, a tube). This static electricity can ignite the fuel. On the other hand, when a conductive layer is laminated on the innermost layer, static electricity is difficult to accumulate even if liquid fuel or the like flows inside the molded product.

  Examples of such a conductive layer include resins used for tubes for automobile fuel piping (for example, aliphatic polyamides such as polyamide 6, polyamide 11, and polyamide 12; polyphenylene sulfide resin, polymetaxylylene adipamide, semi-solid). An aromatic polyamide resin, a polyester resin, etc.) are blended with a conductive filler. The shape of the conductive filler is not particularly limited, and may be granular, flaky, fibrous, or the like.

  Examples of the particulate filler include carbon black, graphite and the like. Examples of the flaky filler include aluminum flakes, nickel flakes, nickel-coated mica and the like. Examples of fibrous fillers include carbon fibers, carbon-coated ceramic fibers, carbon whiskers, aluminum fibers, copper fibers, brass fibers, and stainless steel fibers. The conductive filler is particularly preferably carbon black from the standpoint of availability and conductivity. In particular, acetylene black and furnace black (Ketjen black) are preferably used.

  The amount of the conductive filler contained in the conductive layer is preferably 3 to 35% by mass with respect to the total mass of the conductive layer.

The conductivity of the conductive layer is preferably 10 ⁸ Ω / square or less, more preferably 10 ⁶ Ω / square or less.

1-5. Production method of laminated structure The production method of the laminated structure of the present invention is not particularly limited, and may be a general thermoplastic resin molding machine, for example, an extrusion molding machine, a blow molding machine, a compression molding machine, an injection molding machine, or the like. The aforementioned polyethylene layer (A) and semi-aromatic polyamide layer (C) may be formed in advance, and these may be bonded together with the adhesive layer (B). Further, for example, a polyethylene layer (A), an adhesive layer (B), and a half layer are formed by a co-extrusion molding method (T-die extrusion, inflation extrusion, blow molding, profile extrusion, extrusion coating, etc.), a laminated injection molding method, or the like. The aromatic polyamide layer (C) may be simultaneously molded and laminated.

  You may heat as needed after laminating | stacking a polyethylene layer (A), an adhesive bond layer (B), and a semi-aromatic polyamide layer (C). The residual strain at the time of manufacturing the laminated structure is removed by heating.

  The shape of the laminated structure of the present invention is not particularly limited, and is appropriately selected according to the use of the laminated structure, and is molded into various molded product shapes such as a film shape, a sheet shape, a tube shape, a hose shape, and a bottle shape. It may be. Further, after forming a film-like or sheet-like laminated structure, it may be molded as necessary to obtain a molded product.

2. Molded products Examples of molded products comprising the laminated structure of the present invention include automobile fuel piping tubes or hoses, automotive radiator hoses, brake hoses, air conditioner hoses, wire coating materials, optical fiber coating materials, tubes, hoses, and agricultural products. Films, linings, architectural interior materials (wallpaper, etc.), films such as laminated steel sheets, sheets, automobile radiator tanks, chemical bottles, chemical tanks, chemical containers, tanks such as gasoline tanks, and the like. Since the laminated structure of the present invention has low fuel permeability, it is particularly useful as a tube or hose for automobile fuel piping.

(Automotive fuel piping tube or fuel piping hose)
The automobile fuel piping tube and hose may be in a cylindrical shape, may be in a straight tube shape, may be partially or entirely in a waveform shape, a bellows shape, an accordion shape, etc. It may be processed into a U-shape or the like.

  The semi-aromatic polyamide layer (C) contained in the laminated structure of the present invention has low fuel permeability. Therefore, various fuels (for example, gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, biodiesel fuel, dimethyl ether, LPG, CNG, etc.) flowing inside the automobile fuel pipe or fuel pipe hose are tubes. It is difficult to be released outside the hose. Further, as described above, since the laminated structure of the present invention has high pressure resistance, even if the pressure inside the tube or hose increases, they are not easily damaged. Furthermore, even if the thickness of the semi-aromatic polyamide layer (C) is thin, sufficient strength can be obtained, and further, the fuel permeability can be reduced, so that the cost of the fuel piping tube or the fuel piping hose can be reduced. it can.

  Here, epichlorohydrin rubber, NBR, NBR, and poly are used on the whole or a part of the outer periphery of the tube or hose for automobile fuel piping of the present invention, if necessary, in consideration of abrasion with stones and other parts and flame resistance. Mixture of vinyl chloride, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, acrylic rubber (ACM), chloroprene rubber (CR), ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), mixture of NBR and EPDM A solid or sponge-like protective member (protector) made of a thermoplastic elastomer such as rubber, vinyl chloride, olefin, ester or amide may be disposed.

  In the following, the present invention will be described with reference to examples. By way of example, the scope of the invention is not construed as limiting.

<Polyethylene layer (A)>
The following resin was used for the polyethylene layer (A).
Polyethylene resin (A1): made of prime polymer, Neozex 4005M, density 0.937 g / cm ³ , MFR 0.2 g / 10 min (230 ° C., 2.16 kg load)
Polyethylene resin (A2): made of prime polymer, Hi-Zex 6300M, density 0.951 g / cm ³ , MFR 0.1 g / 10 min (230 ° C., 2.16 kg load)
Polyethylene resin (A3): Prime polymer, Evolve HSP5505 (metallocene catalyst high density polyethylene), density 0.951 g / cm ³ , MFR 0.3 g / 10 min (230 ° C., 2.16 kg load)
Polyethylene resin (A4): Prime polymer, Neozex 2015M, density 0.922 g / cm ³ , MFR 1.2 g / 10 min (230 ° C., 2.16 kg load)

<Adhesive layer (B)>
The following resins were used for the adhesive layer (B).
・ Modified ethylene / α-olefin copolymer (B1)
To an ethylene / α-olefin copolymer having a density of 0.930 g / cm ³ using 4-methyl-1-pentene as a comonomer, 0.10% by mass of maleic anhydride was mixed with a tumbler blender. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer (B1) grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B1) measured in accordance with ASTM D1505 was 0.930 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.10 mass%.

・ Modified ethylene / α-olefin copolymer (B2)
To an ethylene / α-olefin copolymer having a density of 0.930 g / cm ³ using 4-methyl-1-pentene as a comonomer, 0.30% by mass of maleic anhydride was mixed with a tumbler blender. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer (B2) grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B2) measured in accordance with ASTM D1505 was 0.930 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.29 mass%.

・ Modified ethylene / α-olefin copolymer (B3)
To an ethylene / α-olefin copolymer having a density of 0.920 g / cm ³ using 4-methyl-1-pentene as a comonomer, 0.10% by mass of maleic anhydride was mixed with a tumbler blender. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer (B3) grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B3) measured in accordance with ASTM D1505 was 0.920 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.10 mass%.

・ Modified ethylene / α-olefin copolymer (B4)
To an ethylene / α-olefin copolymer having a density of 0.900 g / cm ³ using 4-methyl-1-pentene as a comonomer, 0.10% by mass of maleic anhydride was mixed with a tumbler blender. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer (B4) grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B4) measured in accordance with ASTM D1505 was 0.900 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.10 mass%.

・ Modified ethylene / α-olefin copolymer (B5)
To an ethylene / α-olefin copolymer having a density of 0.940 g / cm ³ using 4-methyl-1-pentene as a comonomer, 0.10% by mass of maleic anhydride was mixed with a tumbler blender. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer (B5) grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B5) measured in accordance with ASTM D1505 was 0.940 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.10 mass%.

・ Modified ethylene / α-olefin copolymer (B6)
0.05% by mass of maleic anhydride was mixed in a tumbler blender with an ethylene / α-olefin copolymer having a density of 0.930 g / cm ³ and 4-methyl-1-pentene as a comonomer. The mixture was extruded at 230 ° C. using a screw having a diameter of 40 mm and an effective length of 1120 mm to obtain a modified ethylene / α-olefin copolymer grafted with maleic anhydride.
The density of the modified ethylene / α-olefin copolymer (B6) measured in accordance with ASTM D1505 was 0.940 g / cm ³ . Moreover, the acid modification rate measured by NMR was 0.05 mass%.

<Semi-aromatic polyamide layer (C)>
Semi-aromatic resin compositions (C1) and (C2) prepared as follows were used for the semi-aromatic polyamide layer (C). However, the resin C3 was an aliphatic polyamide resin (nylon 12, manufactured by Arkema, Rilsamid AESNO TL44).

-Preparation of semi-aromatic polyamide resin First, a semi-aromatic polyamide resin (PA6T) and a semi-aromatic polyamide resin (PA9T) were prepared by the following method.

[Preparation of semi-aromatic polyamide resin (PA6T)]
1986 g (12.0 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-hexanediamine, 1390 g (8.4 mol) of isophthalic acid, 524 g (3.6 mol) of adipic acid, 36.5 g of benzoic acid ( 0.3 mol), sodium hypophosphite-hydrate (5.7 g) and distilled water (545 g) were placed in an autoclave having an internal volume of 13.6 L and purged with nitrogen. The mixture was heated and stirring was started from 190 ° C., and the internal temperature was raised to 250 ° C. over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. The reaction was continued for 1 hour as it was, and then discharged from the spray nozzle installed at the bottom of the autoclave to extract the low condensate. Then, after cooling to room temperature, it grind | pulverized to the particle size of 1.5 mm or less with the grinder, and it dried at 110 degreeC for 24 hours. The obtained low condensate had a water content of 4100 ppm and an intrinsic viscosity [η] of 0.15 dl / g. Next, this low condensate was put into a shelf type solid phase polymerization apparatus, and after the nitrogen substitution, the temperature was raised to 180 ° C. over about 1 hour and 30 minutes. Thereafter, the reaction was performed for 1 hour 30 minutes, and the temperature was lowered to room temperature. The intrinsic viscosity [η] of the obtained polyamide was 0.20 dl / g. After that, in a twin screw extruder with a screw diameter of 30 mm and L / D = 36, melt polymerization was performed at a barrel set temperature of 330 ° C., a screw rotation speed of 200 rp, and a resin supply rate of 6 Kg / h, and a melting point was 266 ° C. and an intrinsic viscosity. A semi-aromatic polyamide resin (PA6T) having [η] of 1.05 dl / g was prepared.

[Preparation of semi-aromatic polyamide resin (PA9T)]
3971 g (23.9 mol) of terephthalic acid, 1907 g (12.0 mol) of 1,9-nonanediamine, 1907 g (12.0 mol) of 2-methyl-1,8-octanediamine, 36.5 g of benzoic acid (0.3 Mol), sodium hypophosphite-hydrate (5.7 g) and distilled water (780 g) were placed in an autoclave having an internal volume of 13.6 L and purged with nitrogen. The mixture was heated and stirring was started from 190 ° C., and the internal temperature was raised to 250 ° C. over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. The reaction was continued for 1 hour as it was, and then discharged from the spray nozzle installed at the bottom of the autoclave to extract the low condensate. Then, after cooling to room temperature, it grind | pulverized to the particle size of 1.5 mm or less with the grinder, and it dried at 110 degreeC for 24 hours. The obtained low condensate had a water content of 4100 ppm and an intrinsic viscosity [η] of 0.13 dl / g. Next, this low condensate was put into a shelf type solid phase polymerization apparatus, and after the nitrogen substitution, the temperature was raised to 180 ° C. over about 1 hour and 30 minutes. Thereafter, the reaction was performed for 1 hour 30 minutes, and the temperature was lowered to room temperature. The intrinsic viscosity [η] of the obtained polyamide was 0.17 dl / g. After that, in a twin screw extruder with a screw diameter of 30 mm and L / D = 36, melt polymerization is performed at a barrel setting temperature of 330 ° C., a screw rotation speed of 200 rp, and a resin supply speed of 5 kg / h, and a melting point is 264 ° C. and an intrinsic viscosity. A semi-aromatic polyamide resin (PA9T) having [η] of 1.04 dl / g was prepared.

Preparation of modified ethylene / α-olefin copolymer Next, a modified ethylene / 1-butene copolymer (PO) in which an unsaturated carboxylic acid or a derivative thereof was graft-modified to the ethylene / 1-butene copolymer was prepared. .

[Preparation of modified ethylene / 1-butene copolymer (PO)]
0.63 mg of bis (1,3-dimethylcyclopentadienyl) zirconium dichloride is placed in a glass flask thoroughly purged with nitrogen, and 1.57 ml of a toluene solution of methylaminoxan (Al; 0.13 mmol / liter). And 2.43 ml of toluene were added to obtain a catalyst solution.
Next, 912 ml of hexane and 320 ml of 1-butene were introduced into a 2 liter stainless steel autoclave sufficiently purged with nitrogen, and the temperature inside the system was raised to 80 ° C. Subsequently, 0.9 mmol of triisobutylaluminum and 2.0 ml of the catalyst solution prepared above (0.0005 mmol as Zr) were injected into the system with ethylene to initiate the polymerization reaction. By continuously supplying ethylene, the total pressure was kept at 8.0 kg / cm 2 -G, and polymerization was carried out at 80 ° C. for 30 minutes.
A small amount of ethanol was introduced into the system to stop the polymerization, and then unreacted ethylene was purged. The obtained solution was poured into a large excess of methanol to precipitate a white solid. The white solid was collected by filtration and dried overnight under reduced pressure to obtain a white solid (ethylene / 1-butene copolymer). [Density = 0.865 g / cm ³ , MFR (ASTM D1238 standard, 190 ° C .: 2160 g load) = 0.5 g / 10 min, 1-butene structural unit content: 4 mol%]

  To 100 parts by mass of the obtained ethylene / 1-butene copolymer, 1.0 part by mass of maleic anhydride and 0.04 parts by mass of peroxide [perhexine 25B, manufactured by NOF Corporation, trademark] were mixed. . The obtained mixture was melt graft modified with a single screw extruder set at 230 ° C. to obtain a modified ethylene / 1-butene copolymer (PO) having the following physical properties. The amount of maleic anhydride graft modification was 0.90% by mass. The intrinsic viscosity [η] measured in a 135 ° C. decalin solution was 1.98 dl / g.

-Preparation of resin composition (C1) and (C2) Subsequently, the above-mentioned semi-aromatic polyamide resin (PA6T) or semi-aromatic polyamide resin (PA9T), modified ethylene / 1-butene copolymer (PO), Were mixed to prepare semi-aromatic polyamide resin compositions (C1) and (C2).

[Preparation of Semi-Aromatic Polyamide Resin Compositions (C1) and (C2)]
The semi-aromatic polyamide resin (PA6T) or semi-aromatic polyamide resin (PA9T), the modified ethylene / 1-butene copolymer (PO), and the antioxidant “Sumilizer GA-80 (trade name, manufactured by Sumitomo Chemical Co., Ltd.) ) Are mixed using a tumbler blender, and the raw material is melted and kneaded at a cylinder temperature of 290 ° C. with a twin-screw extruder (manufactured by Nippon Steel Works, Ltd., TEX30α), then extruded into a strand and cooled in a water bath. After that, the pellets were obtained by drawing the strands with a pelletizer and cutting them to obtain a semi-aromatic polyamide resin (PA6T) or semi-aromatic polyamide resin (PA9T) and a modified ethylene / 1-butene copolymer (PO The mass ratio was 85:15.

[Example 1]
Polyethylene (A1), modified ethylene / α-olefin copolymer (B1), and semi-aromatic polyamide (PA6T) on a molding machine manufactured by Plastic Engineering Co., Ltd., polyethylene (A1) at 230 ° C., modified ethylene / α-olefin The copolymer (B1) was melted separately at 215 ° C., and the semi-aromatic polyamide resin composition (C1) was melted separately at 290 ° C. Each resin was discharged from a molding machine to form a tube having an outer diameter of 8 mm and an inner diameter of 6 mm, and the resin was taken out while cooling.
The thickness of the outer layer (polyethylene layer) / intermediate layer (adhesive layer (modified ethylene / α-olefin copolymer layer)) / inner layer (semi-aromatic polyamide layer) of the obtained laminated structure is 720 μm / 30 μm / 250 μm. (Total thickness 1000 μm).

[Examples 2 to 8 and Comparative Examples 1 to 4]
The outer layer, the intermediate layer, and the inner layer were formed into a tube shape having an outer diameter of 8 mm and an inner diameter of 6 mm in the same manner as in Example 1, except that the resin layer shown in Table 1 was used and the thickness shown in Table 1 was used.

[Evaluation]
The peel strength, fuel permeability, and pressure resistance of the tubular molded bodies (laminated structures) obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1.

(Peel strength)
The tube-shaped molded body was cut into a length of about 200 mm, further cut in half in the longitudinal direction, and the laminated portion at one end was peeled off to obtain a test piece. The obtained test piece was fixed to a Shimadzu autograph (AGS-500B) chuck, peeled at a peeling angle of 180 ° C. and a peeling speed of 300 mm / min, and the peel strength was an average value of 10 mm to 70 mm. It was.

(Fuel permeability)
A pseudo fuel CE10 (toluene / isooctane / ethanol = 45/45/10 vol%) was put into a tube cut into a length of 100 mm. And it was set as the test body by sealing both ends. The test specimen was placed in a temperature lowering device (40 ° C.), the mass of the test specimen before and after the test was measured, and the fuel permeability (g / m ² · day) was evaluated from the mass change.

(Pressure resistance)
Condition adjustment was performed in the water tank which adjusted the tube which cut the tube-shaped molded object to 50 cm length to 40 degreeC. Thereafter, the end on one side was sealed, and a pressure device was connected to the other end to release air. After that, pressurization is performed for 3 minutes at a test stress of an initial pressure of 3.5 MPa, and if not broken, the pressure is increased stepwise by 0.5 MPa, and a test for holding at that pressure for 3 minutes is continuously performed. The internal pressure P (kg / cm ² ) was calculated from the test stress when the tube broke. The pressure resistance was evaluated as A when the internal pressure P at the time of fracture was 27 kg / cm ² or more, and B when it was less than 27 kg / cm ² .

As shown in Table 1, it has a laminated structure comprising a polyethylene layer / adhesive layer (modified ethylene / α-olefin copolymer layer) / semi-aromatic polyamide layer, and the density of the adhesive layer is 0.910. In the case of ˜0.935 g / cm ³ , the peel strength was 28 N / cm or more, the fuel permeability was low, and the pressure resistance evaluation was good (Examples 1 to 8).

  On the other hand, when the density of the adhesive layer was less than 0.910 or more than 0.940, the peel strength was low (Comparative Examples 1 to 3). When the inner layer was an aliphatic polyamide, the peel strength was high, but the fuel permeability was high (Comparative Example 4).

  The laminated structure of the present invention has low fuel permeability, high pressure resistance, and can be further reduced in cost. Therefore, it is suitable for various molded products such as fuel storage tanks and bottles or fuel transfer tubes and hoses.

1 Outer layer (polyethylene layer)
2 Intermediate layer (adhesive layer)
3 Inner layer (semi-aromatic polyamide layer)
100 Laminated structure (molded product)

Claims (15)

A laminated structure in which at least an outer layer is a polyethylene layer (A), an intermediate layer is an adhesive layer (B), and an inner layer is a semi-aromatic polyamide layer (C),
The adhesive layer (B) includes a modified ethylene / α-olefin copolymer obtained by graft-modifying an unsaturated carboxylic acid or a derivative thereof to an ethylene / α-olefin copolymer, and is measured in accordance with ASTM D1505. A laminated structure having a density of 0.910 to 0.935 g / cm ³ . The laminate according to claim 1, wherein the polyethylene layer (A) includes an ethylene / α-olefin (co) polymer having a density of 0.925 to 0.970 g / cm ³ measured according to ASTM D1505. Structure.   The modified ethylene / α-olefin copolymer contained in the adhesive layer (B) includes 0.08 to 5% by mass of the structure derived from the unsaturated carboxylic acid or a derivative thereof. Laminated structure.   The laminated structure according to any one of claims 1 to 3, wherein the modified ethylene / α-olefin copolymer included in the adhesive layer (B) includes a structure derived from maleic anhydride.   The polyethylene layer (A) is an ethylene which is obtained using a metallocene catalyst and has a melt flow rate of 0.01 to 10 g / 10 min measured in accordance with ASTM D1238 (230 ° C., 2.16 Kg). The laminated structure as described in any one of Claims 1-4 containing the (co) polymer of a C3-C16 alpha olefin. The ratio of the thickness ( _Tc ) of the said semi-aromatic polyamide layer (C) with respect to the total thickness (Ts) of the said laminated structure is 0.05-0.4, Any one of Claims 1-5. The laminated structure according to 1. The ratio of the thickness ( _Tc ) of the semi-aromatic polyamide layer (C) to the total thickness (Ts) of the multilayer structure is 0.05 to 0.3. The laminated structure according to 1.   The laminated structure according to any one of claims 1 to 7, further comprising a conductive layer containing a resin and a conductive filler in the innermost layer of the laminated structure. The semi-aromatic polyamide layer (C)
A dicarboxylic acid component in which 40 to 100 mol% is terephthalic acid with respect to the total dicarboxylic acid component, and a diamine component in which 60 to 100 mol% is an aliphatic diamine having 4 to 12 carbon atoms with respect to the total diamine component A semi-aromatic polyamide resin obtained by polymerization;
A modified olefin polymer obtained by modifying an olefin polymer with a compound having a functional group;
The laminated structure according to claim 1, comprising:   The laminated structure according to claim 9, wherein the modified olefin polymer is a modified ethylene / α-olefin copolymer obtained by graft-modifying an ethylene / α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof. The semi-aromatic polyamide layer (C) includes a semi-aromatic polyamide resin and a modified olefin polymer obtained by modifying an olefin polymer with a compound having a functional group,
The semi-aromatic polyamide resin includes a structural unit derived from terephthalic acid [a], a structural unit derived from isophthalic acid [b], and a structural unit derived from an aliphatic dicarboxylic acid [c] having 4 to 10 carbon atoms, Having a structural unit derived from an aliphatic diamine having 4 to 12 carbon atoms,
35 to 50 mol% of structural units derived from the terephthalic acid [a], 25 to 40 mol% of structural units derived from the isophthalic acid [b], and 15 to 35 structural units derived from the aliphatic dicarboxylic acid [c]. Including mol% (provided that the total of [a], [b] and [c] is 100 mol%),
The molar ratio ([a] / [b]) between the structural unit derived from the terephthalic acid [a] and the structural unit derived from the isophthalic acid [b] is 65/35 to 50/50,
The molar ratio ([c] / [b]) between the structural unit derived from the aliphatic dicarboxylic acid [c] and the structural unit derived from the isophthalic acid [b] is 30/70 to 50/50,
The heat of fusion (ΔH) obtained by differential scanning calorimetry (DSC) is 20 to 40 mJ / mg, and its intrinsic viscosity [η] is 0.7 to 1.6 dl / g. The laminated structure according to any one of the above.   The laminated structure according to claim 11, wherein the modified olefin polymer is a modified ethylene / α-olefin copolymer obtained by graft-modifying an ethylene / α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof.   The molded article which consists of a laminated structure as described in any one of Claims 1-12.   The molded product according to claim 13, which is selected from the group consisting of a hose and a tube.   The molded article according to claim 13 or 14, which is a tube for fuel piping.

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