JP2019189678A - Double layer pellet, and manufacturing method of container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer pellet capable of producing a container having both a fuel barrier property and a pressure resistance at a high level by mixing it with a polyethylene resin. A method of manufacturing a container is provided. A multilayer pellet of the present invention is a multilayer pellet having a core layer containing a polyamide resin (A) and a coating layer containing an acid-modified polyolefin resin (B) coating the core layer. And the weight ratio of the core layer to the coating layer (core layer / coating layer) is 20/80 to 80/20, and the polyamide resin (A) is an α, ω-straight chain aliphatic having 4 to 20 carbon atoms. A polyamide (A1) containing a polyamide (A1) containing a dicarboxylic acid constitutional unit derived from a dicarboxylic acid and a diamine constitutional unit derived from metaxylylenediamine, and an aliphatic polyamide (A2), and a polyamide (A1) with respect to the aliphatic polyamide (A2) The weight ratio (A1 / A2) is 30/70 to 80/20. [Selection diagram] None

Description

  The present invention relates to a multilayer pellet and a method for producing a container obtained using the multilayer pellet.

  Conventionally, a polyethylene resin (high density polyethylene) has been mainly used as a resin constituting the fuel storage container. A polyethylene resin container is excellent in mechanical strength, moldability, and economy. However, it is known that a polyethylene resin container has low fuel barrier performance. Therefore, a container having a further improved barrier property against fuel has been demanded as a fuel storage container.

In North America, regulations are tightened with respect to the amount of fuel permeating from a fuel storage container filled with fuel (fuel permeation amount). As a response to this regulation, for example, a fluorination treatment technique in which fluorine gas is blown into a polyethylene resin container and fuel barrier properties are imparted to the innermost layer of the container can be mentioned.
However, in the fluorination treatment technology, untreated parts are generated, and in addition to the technical problem that it is difficult to uniformly impart fuel barrier properties to the innermost layer of the container, there are also problems in terms of safety and cost. there were.

  In recent years, various technologies have been developed in addition to the fluorination treatment technology in response to regulations on the fuel permeation amount. Among them, from the viewpoint of safety and cost, there is an attempt to use a mixed resin obtained by mixing a polyamide resin excellent in fuel barrier property with a polyolefin resin as a base material resin of a container in order to obtain a fuel storage container having high fuel barrier property. Attention has been paid.

For example, Patent Document 1 discloses a pellet having a substantially non-uniform structure including a first component including at least one fuel barrier resin and a second component including at least one compatibilizer. Yes. Specifically, a multilayer resin pellet is disclosed in which a resin having excellent fuel barrier properties such as a polyamide-based resin is used as a core layer, and a compatibilizing agent and a polyolefin-based resin are used as a coating layer covering the core layer.
Patent Document 2 discloses (A) 50 to 97% by weight of polyolefin, (B) a diamine component containing 70% by mole or more of a metaxylylenediamine structural unit, and an α, ω-linear chain having 4 to 20 carbon atoms. 2 to 45% by weight of a polyamide resin containing a dicarboxylic acid component containing 70 mol% or more of a structural unit having a molar ratio of aliphatic dicarboxylic acid to isophthalic acid of 3: 7 to 10: 0, and (C) a modified polyolefin and A thermoplastic resin composition excellent in fuel barrier properties comprising 1 to 45% by weight of a styrene copolymer is disclosed.

International Publication No. 1995/12631 JP 2005-206806 A

  However, the molded body disclosed in Patent Document 1 has room for further improvement in fuel barrier properties. In addition, in a container made by hollow molding using the thermoplastic resin composition disclosed in Patent Document 2 as a base resin, the barrier strength is excellent and the fuel permeation amount is small, but the pressure strength is improved. There was room for improvement.

  Therefore, the present invention has been made to solve the above problems, and provides a multilayer pellet capable of producing a container having both fuel barrier properties and pressure strength by mixing with polyethylene resin, and further, It aims at providing the manufacturing method of the container which uses mixed resin which mixed this multilayer pellet with polyethylene resin as base resin.

As a result of intensive studies in view of the above problems, the present inventors have determined that the core layer and the coating layer constituting the multilayer pellet have a specific weight ratio (core layer / coating layer), and the polyamide resin (A ) Contains a polyamide (A1) and an aliphatic polyamide (A2) at a specific weight ratio (A1 / A2), so that a multilayer pellet capable of producing a container having both fuel barrier properties and pressure strength at a high level is obtained. The inventors have found that the present invention can be obtained and have completed the present invention.
That is, the present invention is as follows.

[1] A multi-layer pellet having a core layer containing a polyamide-based resin (A) and a coating layer containing an acid-modified polyolefin resin (B) that covers the core layer, the core layer corresponding to the coating layer The weight ratio (core layer / coating layer) is 20/80 to 80/20, and the polyamide resin (A) is a dicarboxylic acid derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. Polyamide (A1) containing an acid structural unit and a diamine structural unit derived from metaxylylenediamine, and an aliphatic polyamide (A2), the weight ratio of the polyamide (A1) to the aliphatic polyamide (A2) ( Multilayer pellets in which A1 / A2) is from 30/70 to 80/20.
[2] The polyamide-based resin (A) is composed of the polyamide (A1) and the aliphatic polyamide (A2), and the polyamide (A1) is composed of a dicarboxylic acid structural unit derived from adipic acid and metaxylylenediamine. The multilayer pellet according to the above [1], which is a polyamide comprising a derived diamine structural unit, and the aliphatic polyamide (A2) is poly (caprolactam).
[3] The melting peak temperature (T _H ) of the melting peak on the high temperature side and the melting on the low temperature side of the two melting peaks derived from the polyamide-based resin (A) in the DSC curve obtained by differential scanning calorimetry of heat flux The difference between the peak melting peak temperature (T _L ) (ΔT ₁ = T _H −T _L ) and the melting peak temperature (T _A1 ) of the polyamide (A1) and the melting peak temperature of the aliphatic polyamide (A2) ( The multilayer pellet according to [1] or [2], wherein an absolute value (ΔT ₂ = | T _A1 −T _A2 |) of a difference from T _A2 ) satisfies the relationship of the following formula 1.
(Formula 1) | ΔT ₁ −ΔT ₂ | ≦ 3 ° C.
[4] Of the two melting peaks derived from the polyamide-based resin (A), the difference (ΔT) between the melting peak temperature (T _H ) of the melting peak on the high temperature side and the melting peak temperature (T _L ) of the melting peak on the low temperature side. ₁ = _T H -T _L) is, 10 ° C. or higher 18 ° C. or less, multilayer pellets according to [3].
[5] The content of the acid component derived from the acid-modified polyolefin resin (B) in the coating layer is 0.05 to 5% by weight, as described in any one of the above [1] to [4]. Multi-layer pellets.
[6] In any one of [1] to [5], the weight ratio (A1 / A2) of the polyamide (A1) to the aliphatic polyamide (A2) is 30/70 to 70/30. The multilayer pellet as described.
[7] Melt kneading obtained by supplying the multilayer pellet (X) and high density polyethylene resin (Y) according to any one of [1] to [6] to an extruder and melt-kneading them. A method for manufacturing a container in which a softened parison formed by extruding a product is sandwiched between molds and blow-molded, and the content ratio of the polyamide-based resin (A) derived from the multilayer pellet (X) in the container is The manufacturing method of a container which supplies a multilayer pellet (X) to an extruder so that it may become 1 to 10 weight%.

  According to the present invention, it is possible to provide a multilayer pellet capable of producing a container having excellent fuel barrier properties, a small amount of fuel permeation, and excellent pressure strength. The manufacturing method of the container made into resin can be provided.

[Multilayer pellet]
The multilayer pellet of the present invention is a multilayer pellet having a core layer containing a polyamide-based resin (A) and a coating layer containing an acid-modified polyolefin resin (B) that covers the core layer. The weight ratio of the core layer to the core (core layer / coating layer) is 20/80 to 80/20, and the polyamide resin (A) is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The weight ratio of the polyamide (A1) to the aliphatic polyamide (A2) containing the polyamide (A1) and the aliphatic polyamide (A2) including the dicarboxylic acid structural unit and the diamine structural unit derived from metaxylylenediamine ( A1 / A2) is 30 / 70-80 / 20.
Thereby, the multilayer pellet which can manufacture the container which is excellent in fuel-barrier property, has little fuel permeation | transmission quantity, and was excellent in the compressive strength is obtained.

The pellet of the present invention must have a multilayer structure having a core layer and a coating layer that covers the core layer.
The pellet structure does not have a multilayer structure, and the polyamide resin (A) contained in the core layer and the acid-modified polyolefin resin (B) contained in the coating layer are each made into a single-layer pellet and specified in the present invention. Even if the container is manufactured using the specified components at a specified weight ratio, the desired fuel barrier property can be obtained, but the container may be inferior in pressure resistance, and both the fuel barrier property and pressure resistance can be achieved at a high level. Therefore, the special effect of the present invention cannot be obtained.
The reason for this is not clear, but can be considered as follows.
When manufacturing a container using a mixed resin of a multilayer pellet having a multilayer structure having a core layer and a coating layer covering the core layer and a high-density polyethylene resin as a base resin, the base resin constituting the container It is considered that the polyamide-based resin (A) can be easily oriented in layers. Furthermore, when the container is manufactured, the acid-modified polyolefin resin (B) contained in the coating layer causes the polyamide resin (A) and the resin such as the high-density polyethylene resin (Y) to be contained in the base resin constituting the container. It is considered that the adhesion at the interface of the film becomes good. As a result, it is thought that it has the outstanding effect which can make fuel barrier property and pressure-resistant strength compatible at a high level.

The weight ratio of the core layer to the coating layer (core layer / coating layer) is 20/80 to 80/20, preferably 30/70 to 50/50, more preferably 35/65 to 45/55.
When the weight ratio of the core layer is too low, the fuel barrier property may be inferior.
On the other hand, when the weight ratio of the core layer is too high, the adhesiveness at the interface between the polyamide-based resin (A) contained in the core layer and a resin such as a high-density polyethylene resin (Y) may be inferior when manufacturing the container. There is.

(1) Core layer In the present invention, the polyamide resin (A) constituting the core layer is composed of a dicarboxylic acid structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms and metaxylylenediamine. The polyamide (A1) containing the derived diamine structural unit and the aliphatic polyamide (A2) are contained at a weight ratio (A1 / A2) of 30/70 to 80/20.
Thereby, the multilayer pellet which can manufacture the container which is excellent in fuel-barrier property, has little fuel permeation | transmission quantity, and was excellent in the compressive strength is obtained.

The polyamide resin (A) of the present invention contains polyamide (A1) and aliphatic polyamide (A2) as essential components.
When the polyamide-based resin (A) does not contain the polyamide (A1), a desired pressure strength can be obtained, but the container may be inferior in fuel barrier properties.
Further, when the polyamide-based resin (A) does not contain the aliphatic polyamide (A2), the desired fuel barrier property can be obtained, but there is a possibility that the container has room for further improvement in pressure strength.

The weight ratio (A1 / A2) of the polyamide (A1) to the aliphatic polyamide (A2) is 30/70 to 80/20, preferably 30/70 to 70/30, more preferably 35/65 to 65 /. 35.
When the aliphatic polyamide (A2) ratio is too high, a desired pressure strength can be obtained, but there is a possibility that the container has poor fuel barrier properties.
On the other hand, when the aliphatic polyamide (A2) ratio is too low, the desired fuel barrier property can be obtained, but there is a possibility that the container has room for further improvement in pressure resistance.

The polyamide-based resin (A) is preferably a mixture obtained by melt-kneading the polyamide (A1) and the aliphatic polyamide (A2) at a specific weight ratio (A1 / A2).
The degree to which the polyamide (A1) and the aliphatic polyamide (A2) are melt-kneaded is not particularly limited, but the polyamide (A1) and the aliphatic polyamide (A2) are appropriately melt-kneaded and appropriately compatible. It is preferable to produce a multilayer pellet using the polyamide-based resin (A) thus obtained as a core layer.
Thereby, it is easy to express both the fuel barrier properties and the pressure strength effect, and it is possible to obtain a multilayer pellet that can produce a container having excellent fuel barrier properties and a small amount of fuel permeation, and excellent pressure strength. A special effect is more easily exhibited.
In this specification, “moderately compatible” means a state in which the polyamide (A1) and the aliphatic polyamide (A2) are completely compatibilized by melt-kneading the polyamide (A1) and the aliphatic polyamide (A2). However, it is possible to determine a moderately compatible state based on the following indicators.

Among the two melting peaks derived from the polyamide-based resin (A) in the DSC curve obtained by heat flux differential scanning calorimetry, the melting peak temperature ( _TH ) of the melting peak on the high temperature side and the melting peak of the melting peak on the low temperature side the difference between the difference _{(ΔT 1 = T H -T L} ), and the melting peak temperature of the polyamide melting peak temperature of _{(A1) (T} A1) and the aliphatic polyamide _{(A2) (T} A2) between the temperature _{(T L)} When the absolute value of (ΔT ₂ = | T _A1 −T _A2 |) satisfies the relationship of the following formula 1, it can be determined that the effect of the present invention is easily obtained and is in an appropriately compatible state.
(Formula 1) | ΔT ₁ −ΔT ₂ | ≦ 3 ° C.
That is, when the above | ΔT ₁ −ΔT ₂ | is in the above range, it can be determined that the effect of the present invention is easily obtained and is in a moderately compatible state.
The melting peak temperature in this specification, that is, the melting point, is based on the melting peak in the DSC curve obtained by heat flux differential scanning calorimetry by the heat flux differential scanning calorimetry according to the method described in JIS K7121 (1987). Desired.
Specifically, the temperature difference (ΔT ₁ ) between the two melting peaks derived from the polyamide-based resin (A) is measured using only the core layer as a sample to be measured, that is, the polyamide-based resin (A) constituting the core layer is measured. A sample to be measured is placed in a container of a DSC apparatus, and a DSC curve is obtained when the temperature is raised from room temperature to 300 ° C. at a heating rate of 10 ° C./min without performing heat treatment. Then, the melting peak temperature (T _H ) of the melting peak on the high temperature side and the melting peak temperature (T _L ) of the melting peak on the low temperature side are read from the obtained DSC curve, respectively, and the melting peak temperature (T _H ) of the melting peak and the temperature difference between the melting peak temperature _{(T L)} of the melting peak _{(ΔT 1 = T H -T L} ) is obtained.
On the other hand, the absolute value of the difference between the melting peak temperature _{(T A2)} of the melting peak temperature _{(T A1)} and the aliphatic polyamide (A2) of the polyamide _{(A1) (ΔT 2 = |} T A1 -T A2 |) is melted Using the polyamide (A1) before kneading and the aliphatic polyamide (A2) before melt kneading as samples to be measured, DSC curves are obtained by the same measuring method as described above. Here, the melting peak temperature of the melting peak of the polyamide (A1) alone before the melt kneading is defined as “melting point (T _A1 ) of the polyamide ( _A1 )”, and the melting peak of the aliphatic polyamide (A2) alone before the melt kneading. The melting peak temperature of “Aliphatic polyamide (A2) is defined as the melting point (T _A2 )”.
The melting peak temperature of the melting point from DSC curves respectively obtained _{(T A1)} and melting point reading _{(T A2),} respectively, melting peak temperature _{(T A1)} and the aliphatic polyamide of the polyamide _{(A1) (A2) (T} A2 ) To obtain an absolute value (ΔT ₂ ).
Furthermore, the temperature difference _{(ΔT 1 = T H -T L} ) and the absolute value of the difference _{(ΔT 2 = | T A1 -T} A2 |) with the absolute value of the color difference (| ΔT ₁ -ΔT ₂ |) is calculated.

  In the present invention, the polyamide (A1) and the aliphatic polyamide (A2) are appropriately melt-kneaded at a specific weight ratio (A1 / A2) so that the polyamide (A1) and the aliphatic polyamide (A2) are appropriately mixed. By making it in a compatible state, it becomes easy to obtain a multi-layer pellet that can produce a container that has excellent fuel barrier properties, a small amount of fuel permeation, and excellent pressure strength. The reason for this is not clear, but can be considered as follows.

  Polyamide (A1) is a resin that exhibits an effect of being particularly excellent in fuel barrier properties among polyamides, and aliphatic polyamide (A2) is considered to be a resin that contributes particularly to ensuring pressure-resistant strength among polyamides.

  It is preferable that the polyamide (A1) and the aliphatic polyamide (A2) are melt-kneaded so as to be appropriately compatible to produce a multilayer pellet using the polyamide resin (A) as a core layer. The container obtained by mixing the multi-layer pellets thus produced with a polyethylene resin to form a base resin and molding the base resin facilitates coexistence of fuel barrier properties and pressure strength. It is easy to obtain a special effect.

When the polyamide (A1) and the aliphatic polyamide (A2) are melt-kneaded, the end points of both polyamides react with each other or amide exchange occurs, so that the compatibilization proceeds.
Here, the compatibilization of the polyamide (A1) and the aliphatic polyamide (A2) is derived from the polyamide resin (A) in the DSC curve obtained by measuring the heat flux differential scanning calorimetry as the degree thereof progresses. the difference between the two melting peak temperature of the high temperature side of the melting peak of the melting peak (T _H) and the low temperature side of the melting peak of the melting peak temperature _{(T L) (ΔT 1 =} T H -T L) is varied in (hereinafter, also referred to the difference _{(ΔT 1 = T H -T L} ), the temperature difference between the two melting peaks derived from the polyamide resin (a) and ([Delta] T _1)).
When the polyamide (A1) and the aliphatic polyamide (A2) are melt-kneaded and the compatibilization proceeds, the temperatures of the two melting peaks derived from the polyamide-based resin (A) in the DSC curve obtained by heat flux differential scanning calorimetry The difference (ΔT ₁ ), the melting peak temperature (T _A1 ) of the polyamide (A1) and the aliphatic polyamide (A ₁ ) obtained from the polyamide (A 1) and the aliphatic polyamide (A 2) independently by heat flux differential scanning calorimetry When the absolute value (ΔT ₂ = | T _A1 −T _A2 |) of the difference in the melting peak temperature (T _A2 ) of _A2 ) is compared, the change tends to be relatively large, that is, | ΔT ₁ −ΔT ₂ | It tends to be relatively large.
On the other hand, if the polyamide (A1) and the aliphatic polyamide (A2) are melt-kneaded so as not to be excessively compatibilized, they are derived from the polyamide resin (A) in the DSC curve obtained by measuring the heat flux differential scanning calorimetry. And the melting peak temperature (T1) of the polyamide (A1) obtained by measuring the heat flux differential scanning calorimetry of the polyamide (A1) and the aliphatic polyamide (A2) independently of each other (ΔT ₁ ). _When the absolute value (ΔT ₂ = | T _A1 −T _A2 |) of the difference between the melting peak temperatures (T _A2 ) of _A1 ) and the aliphatic polyamide (A2) is compared, the change tends to be relatively small, that is, | ΔT ₁ −ΔT ₂ | tends to be relatively small.

In the polyamide resin (A) obtained by melt-kneading so that the polyamide (A1) and the aliphatic polyamide (A2) are not excessively compatibilized, the polyamide resin (A) has a heat flux differential scanning calorific value. The temperature difference (ΔT ₁ ) between the two melting peaks in the DSC curve obtained by measurement is preferably 10 ° C. or higher and 18 ° C. or lower, more preferably 12 ° C. or higher and 17.5 ° C. or lower, and further preferably 14 ° C. or higher and 17 ° C. or lower. It is as follows.
When the temperature difference (ΔT ₁ ) of the melting peak is in the above range, the compatibility between the fuel barrier property and the pressure strength is facilitated, and the special effects of the present invention are easily obtained.

  As a method of appropriately compatibilizing the polyamide (A1) and the aliphatic polyamide (A2), the temperature and screw rotation speed are adjusted among the melt-kneading conditions in the core layer forming extruder when the multilayer pellets are produced. By doing so, it can be made to compatibilize moderately. For example, when the melt kneading temperature is too high or the screw rotation speed is increased too much, the compatibilization proceeds excessively.

  Hereinafter, the polyamide (A1) and the aliphatic polyamide (A2) constituting the polyamide resin (A) will be described.

(Polyamide (A1))
The polyamide (A1) includes a dicarboxylic acid structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms and a diamine structural unit derived from metaxylylenediamine, and has 4 to 20 carbon atoms. It preferably comprises a dicarboxylic acid structural unit derived from an α, ω-linear aliphatic dicarboxylic acid and a diamine structural unit derived from metaxylylenediamine.

<Dicarboxylic acid structural unit>
The dicarboxylic acid structural unit constituting the polyamide (A1) is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.
The carbon number of the dicarboxylic acid structural unit derived from the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is 4 to 20, preferably 5 to 16, more preferably 5 to 12, and still more preferably. 6-10.

As a dicarboxylic acid structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, a succinic acid unit, a glutaric acid unit, an adipic acid unit, a pimelic acid unit, a suberic acid unit, an azelaic acid unit, Examples include a sebacic acid unit, a decanedioic acid unit, an undecanedioic acid unit, and a dodecanedioic acid unit.
Among these, from the viewpoint of easily obtaining a desired fuel barrier property, it is preferable to contain 90 mol% or more of adipic acid units, more preferably 95 mol% or more of adipic acid units, and only consist of adipic acid units. Is more preferable.

  In this invention, in the range which does not impair the objective effect of this invention, you may contain other dicarboxylic acid components other than C4-C20 alpha, omega-linear aliphatic dicarboxylic acid. Examples of other dicarboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and orthophthalic acid, preferably 10 mol% or less of all carboxylic acid structural units, and more preferably 5 mol% or less, More preferably, no other dicarboxylic acid component is contained.

<Diamine constitutional unit>
The diamine structural unit constituting the polyamide (A1) is derived from metaxylylenediamine.
The diamine structural unit constituting the polyamide (A1) may contain a diamine component other than metaxylylenediamine as long as the objective effect of the present invention is not impaired. Examples of other diamine components include paraxylylenediamine, orthoxylylenediamine, paraphenylenediamine, metaphenylenediamine, and the like. The diamine structural unit constituting the polyamide (A1) preferably contains 90% by mole or more of metaxylylenediamine units, more preferably 95% by mole or more of metaxylylenediamine units, and only the metaxylylenediamine units. More preferably, it consists of.

The polyamide (A1) contains one or more of the above-mentioned dicarboxylic acid structural units, and contains one or more of the above-mentioned diamine structural units.
Specifically, the polyamide (A1) containing the dicarboxylic acid structural unit and the diamine structural unit is obtained by polycondensation of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms and metaxylylenediamine. be able to.
Specific examples of the polyamide (A1) include polymetaxylylene adipamide.

The relative viscosity of the polyamide (A1) is not particularly limited, but is preferably 1 to 6, more preferably 2 from the viewpoint of appropriately compatibilizing the polyamide (A1) in the polyamide resin (A) constituting the core layer. -5, more preferably 2-4.
The relative viscosity in this specification is a value measured using sulfuric acid as a reagent based on the method described in Appendix JA of JIS K6920-2: 2009.

Viewpoint melting point of the polyamide _(A1) (T A1) is not particularly limited, for the polyamide (A) in the continuous phase of the high-density polyethylene resin (Y) in producing the container to form a dispersed phase dispersed in layers Therefore, it is preferably 200 to 260 ° C, more preferably 210 to 250 ° C, still more preferably 220 to 240 ° C.

(Aliphatic polyamide (A2))
The aliphatic polyamide (A2) is a polyamide containing as a main component a structural unit that contains an amide bond and does not contain an aromatic ring in the molecular skeleton.
As used herein, “main component” means that the constituent units of the aliphatic polyamide that do not contain an aromatic ring are more than 50 mol%, preferably 80 to 100 mol%, more preferably 90 to 100 mol%. More preferably, it means that it consists only of structural units of aliphatic polyamide.
Specific examples of the aliphatic polyamide (A2) include poly (6-aminohexanoic acid) (nylon 6), also known as poly (caprolactam), poly (laurolactam) (nylon 12), poly (hexamethylene adipamide) ) (Nylon 6,6), poly (7-aminoheptanoic acid) (nylon 7), poly (8-aminooctanoic acid) (nylon 8), poly (9-aminononanoic acid) (nylon 9), poly (10- Aminodecanoic acid (nylon 10), poly (11-aminoundecanoic acid) (nylon 11), poly (hexamethylene sebacamide) (nylon 6,10), poly (decamethylene sebacamide) (nylon 10,10) , Poly (hexamethylene azelamide) (nylon 6,9), poly (tetramethylene adipamide) (nylon 4,6), poly (tetra Tylene sebacamide) (nylon 4, 10), poly (pentamethylene adipamide) (nylon 5, 6), and poly (pentamethylene sebacamide) (nylon 5, 10) homopolymers; hexamethylene adipamide And copolymers such as caprolactam copolymer (nylon 6, 6/6).
Among these, poly (caprolactam) (nylon 6), poly (hexamethylene adipamide) (nylon 6,6), hexamethylene adipamide-caprolactam copolymer ( Nylon 6,6 / 6) is preferable, and poly (caprolactam) (nylon 6) is particularly preferable.

  The relative viscosity of the aliphatic polyamide (A2) is not particularly limited, but from the viewpoint of appropriately compatibilizing the aliphatic polyamide (A2) in the polyamide resin (A) constituting the core layer, preferably 1 to 7, More preferably, it is 2-6, More preferably, it is 3-5.

The melting point (T _A2 ) of the aliphatic polyamide (A2) is not particularly limited, but is preferably 190 from the viewpoint of appropriately compatibilizing the aliphatic polyamide (A2) in the polyamide resin (A) constituting the core layer. It is -250 degreeC, More preferably, it is 200-240 degreeC, More preferably, it is 210-230 degreeC. However, the aliphatic polyamide (A2) has a melting point different from the melting point (T _A1 ) of the polyamide (A1).

(Other ingredients)
In the present invention, the core layer contains the polyamide resin (A) as an essential component, but does not impair the object effects of the present invention, and the temperature difference (ΔT ₁ ) between the two melting peaks derived from the polyamide resin (A). As long as a melting peak that makes it difficult to determine the value is not measured, it may further contain other components.
Examples of other components include polyethylene, polypropylene, polystyrene, and the like. The content of other components is preferably 3 parts by weight or less, more preferably 1 part by weight or less, based on 100 parts by weight of the total resin (including other components) constituting the core layer. It is more preferable that no other components are contained in

(2) Coating layer In this invention, a coating layer contains acid-modified polyolefin resin (B) as an essential component.

(Acid-modified polyolefin resin (B))
The acid-modified polyolefin resin (B) is obtained by graft-modifying polyolefin with an unsaturated carboxylic acid or an anhydride thereof, and is generally used as an adhesive resin.
As the polyolefin to be the precursor of the acid-modified polyolefin resin (B), the same polyolefins listed in the polyolefin resin (C) described later can be used, and among them, mechanical strength, moldability From the viewpoint of excellent economy, polyethylene is preferred, and among these, high density polyethylene having a density of 940 to 960 kg / m ³ is more preferably used.

  Examples of unsaturated carboxylic acids or anhydrides include acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, chloromaleic acid, butenyl succinic acid, and these acids An anhydride etc. are mentioned. Among these, maleic acid and maleic anhydride are preferable.

As a method for obtaining an acid-modified polyolefin by graft copolymerization of the unsaturated carboxylic acid or its anhydride with a polyolefin, various conventionally known methods can be used.
For example, a method in which a polyolefin is melted with an extruder or the like, and a graft monomer is added for copolymerization; a method in which the polyolefin is dissolved in a solvent and a graft monomer is added for copolymerization; And the like, and the like.

The content of the acid component derived from the acid-modified polyolefin resin (B) in the coating layer is preferably 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, and still more preferably 0.2 to 2% by weight.
When the content of the acid component is in the above range, when producing a container using a mixed resin of a multi-layer pellet and a resin such as a high-density polyethylene resin as a base resin, the acid-modified polyolefin resin (B) Adhesiveness at the interface between the polyamide-based resin (A) and the resin such as high-density polyethylene resin (Y) is improved, and a container having excellent fuel barrier properties and a small amount of fuel permeation and excellent pressure strength is obtained. It becomes easy to be done.

By adding the non-acid-modified polyolefin resin (C) to the acid-modified polyolefin resin (B) having a specific modification rate, the content of the acid component in the coating layer can be adjusted.
The modification rate of the acid-modified polyolefin resin is preferably 0.1 to 8% by weight, more preferably 0.2 to 5% by weight, and still more preferably 0.3 to 3% by weight.
When the modification rate is in the above range, it is easy to obtain a multi-layer pellet that can produce a container that has excellent fuel barrier properties, a small amount of fuel permeation, and excellent pressure strength.
The modification rate in this specification is calculated from the value of the acid value by obtaining the acid value by a neutralization titration method based on the method described in JIS K0070 (1992). The content of the acid component derived from the acid-modified polyolefin resin (B) in the coating layer is the content ratio of the acid-modified polyolefin resin (B) in the coating layer to the acid modification rate of the acid-modified polyolefin resin. It is also possible to calculate by applying.

(Polyolefin resin (C))
The polyolefin-based resin (C) refers to an unmodified polyolefin resin that has not been modified with an acid or the like.
Examples of polyolefin resins include polyethylene represented by low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, and the like; propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, and the like. Polypropylene; 1-polybutene, 1-polymethylpentene and other ethylene hydrocarbon homopolymers having 2 or more carbon atoms; α-olefin homopolymer having 3 to 20 carbon atoms; α-olefin having 3 to 20 carbon atoms And a copolymer of an α-olefin having 3 to 20 carbon atoms and a cyclic olefin.
Among these, polyethylene is preferable, and among these, high density polyethylene having a density of 940 to 960 kg / m ³ is more preferably used.

  Although depending on the acid modification rate of the acid-modified polyolefin resin (B), the weight ratio (B / C) of the acid-modified polyolefin resin (B) to the polyolefin resin (C) contained in the coating layer is preferably 20/80 to 60/40, more preferably 30/70 to 50/50.

(Other ingredients)
In the present invention, the coating layer contains the acid-modified polyolefin resin (B) as an essential component, and preferably further contains the polyolefin resin (C), but within the range not impairing the object effects of the present invention. You may contain a component.
Examples of other components include polyamide, polycarbonate, polyphenylene ether, polystyrene, and the like. The content of other components is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, with respect to 100 parts by weight of the total resin (including other components) constituting the coating layer. More preferably, it is 3 parts by weight or less.

[container]
The container of this invention is a container which uses the mixed resin of multilayer pellet (X) mentioned above and polyolefin resin (Y) as base resin.
As the polyolefin resin (Y), the same resins as the polyolefin resins enumerated in the above-mentioned polyolefin resin (C) can be used. Among them, polyethylene is preferable, and among them, the density is 940 to 960 kg / m ³ . High density polyethylene is more preferably used.

The container of the present invention contains the multilayer pellet (X) and the polyolefin-based resin (Y) described above as essential components as the base resin, and preferably may contain a recycled resin (Z) described later. Other components may be further contained within a range not impairing the object effects of the invention.
As other components, for example, an inorganic substance having a scaly or layered structure such as smectite clay, vermiculite, halloysite, and mica is added in order to improve the fuel barrier property of the container and reduce the fuel permeation amount. May be. As other additives, various additives such as antistatic agents, conductivity imparting agents, lubricants, antioxidants, ultraviolet absorbers, flame retardants, metal deactivators, pigments, dyes, crystal nucleating agents, fillers, etc. An agent can be appropriately blended as necessary.

The container of the present invention forms a dispersed phase in which the above-described polyamide-based resin (A) contained in the above-described multilayer pellet (X) is dispersed in layers in a continuous phase of the high-density polyethylene resin (Y). It is preferable.
In this specification, “layered” means that in the cross section of the resin layer, most of the polyamide-based resin (A) dispersed in the high-density polyethylene resin (Y) is fine and relative to the thickness direction of the resin layer. The state which exists so that it may overlap in the state extended | stretched in the orthogonal direction.
As a result, it is easy to obtain a container having excellent fuel barrier properties, a small amount of fuel permeation, and excellent pressure strength. As a method for confirming that the polyamide-based resin (A) is dispersed in layers in the high-density polyethylene resin (Y), for example, the container is cut, and the cut surface is coated with iodine tincture to form the polyamide-based resin (A ) Can be confirmed.

The weight ratio (X / Y) of the multilayer pellet (X) to the high-density polyethylene resin (Y) is preferably 3/97 to 30/70, more preferably 5/95 to 25/75, still more preferably 10 / 90-20 / 80.
When the weight ratio (X / Y) is in the above range, a container having excellent fuel barrier properties and a small amount of fuel permeation and excellent pressure strength can be easily obtained.
In addition, the content of the multilayer pellet (X) is preferably 5 to 30% by weight, more preferably 7 to 20% by weight, and still more preferably 8 to 15% with respect to the total amount (100% by weight) of the base resin. % By weight.
When the content of the multilayer pellet (X) is in the above range, a container having excellent fuel barrier properties, low fuel permeation amount, and excellent pressure strength can be easily obtained.

In the present invention, a recycled resin (Z) obtained by blow molding a mixed resin of a multilayer pellet (X) and a high density polyethylene resin (Y) as a base resin and crushing the resulting container is used as a raw resin. Can be used.
Recycled resin (Z) may be recovered from burrs or defective products that are formed during the manufacturing process of the container and crushed, or recycled into pellets with a single-screw or twin-screw extruder. It may be processed. In particular, the polyamide-based resin that is a constituent component of the recycled resin (Z) has a hygroscopic property. For this reason, from the viewpoint of suppressing the possibility of foaming due to moisture absorption and the risk of lowering fuel barrier properties and pressure strength, those immediately after molding or those having a moisture content of 1000 ppm or less by performing dehumidification drying or the like are preferably used. .
The content of the recycled resin (Z) is preferably 80% by weight or less, more preferably 60% by weight or less, with respect to the total amount (100% by weight) of the base resin. On the other hand, from the viewpoint of using the recycled resin, the content of the recycled resin (Z) is preferably approximately 20% by weight or more.

When the recycled resin (Z) is used for the production of the container, the polyamide resin (A) contained in the recycled resin (Z) is finely dispersed in the high-density polyethylene resin or the like. Does not contribute much to improvement. Therefore, the fuel barrier property is ensured by the content ratio of the polyamide resin (A) derived from the multilayer pellet. From the above viewpoint, supplying the multilayer pellet (X) to the extruder so that the content ratio of the polyamide-based resin (A) derived from the multilayer pellet (X) in the container is 1 to 10% by weight. Preferably, it is more preferable to supply so that it may become 2 to 8 weight%.
The shape of the container of the present invention is not particularly limited, but may be a hollow molded body, for example, a bottle shape or a tank shape. The container of the present invention is excellent in fuel barrier properties, has a small amount of fuel permeation, and is excellent in pressure strength. Therefore, it can be particularly preferably used as a fuel storage container such as a gasoline tank.

[Manufacturing method of container]
The container of the present invention is preferably produced by blow molding.
Specifically, a soft parison formed by extruding a melt-kneaded product obtained by melt-kneading the above-mentioned mixed pellets (X) and high-density polyethylene resin (Y) is sandwiched between molds and blown. A method of manufacturing by molding is preferred.
The method for sandwiching the parison between the molds is not particularly limited. For example, a method of placing the parison between the split molds, clamping the split molds, and sandwiching the parison can be mentioned. The method for blow-molding the parison is not particularly limited. For example, a molded body having a shape corresponding to the mold shape, that is, a container can be produced by blowing a pressurized gas into the parison.
Usually, when a parison in a softened state is sandwiched by using a split mold, the opposed inner surfaces of the parison are fused to each other at a position where the parison is sandwiched by the peripheral edge of the mold cavity, thereby generating a pinch-off portion. The outside from the pinch-off portion is an excess portion called a burr. Finally, the burrs are removed to obtain a container. As a result, the container obtained by the method has a pinch-off portion on the whole or a part of the periphery.
When the pressure in the container rises or when the container is dropped, the base resin of the container is a polyethylene resin and a polyamide resin (A1) compared to the case where the base resin of the container is a polyethylene resin alone. When the polyamide resin (A1) is stretched and dispersed in the polyethylene resin along the circumferential direction of the container wall, the vicinity of the pinch-off part of the container is easily broken. This is considered to be because a slight crack generated in the pinch-off portion due to an increase in internal pressure, a drop, or the like reaches the interface between the polyethylene resin and the polyamide resin (A1), and the two peel off at the interface.

The container of the present invention can be produced by blow molding a mixed resin obtained by mixing the above-described multilayer pellets with a polyolefin resin (preferably a high density polyethylene resin) as a base resin.
In the container manufactured by the method of the present invention, a dispersion layer in which the polyamide-based resin (A) is dispersed in layers in the continuous phase of the high-density polyethylene resin (Y) is formed. In the container manufactured by the method of the present invention, the polyamide resin (A) identifies the polyamide (A1) and the aliphatic polyamide (A2) even if the layered dispersion layer of the polyamide resin (A) is formed. The ratio of the acid-modified polyolefin resin (B) is present in contact with the polyamide resin (A), so that the interface between the polyamide resin (A) and the resin such as the high-density polyethylene resin (Y) is reduced. It is considered that the adhesiveness is good. From this, according to the manufacturing method of the container of this invention, the container excellent in pressure | voltage resistant strength is obtained, without reducing the intensity | strength of the pinch-off part mentioned above.

The following examples further illustrate the present invention, but the present invention is not limited to these examples.
The manufacture example of the multilayer pellet used in the Example and the manufacture example of the multilayer pellet and single layer pellet which were used by the comparative example were shown below.

(1) Production of multilayer pellets (Production Example 1)
For the production of multi-layer pellets, after pre-kneading the resin composition for the core layer, a single-screw extruder for forming the core layer and a single-screw extruder for forming the coating layer (outer layer) are also provided, and a large number are provided on the outlet side. A single-screw kneading extruder for producing a multi-layer pellet provided with a die capable of co-extrusion in the form of a multi-layer strand was used.
(Preliminary kneading of the resin composition for the core layer)
Polymetaxylylene adipamide as polyamide (A1) (“MX nylon 6121” manufactured by Mitsubishi Gas Chemical Co., Inc., relative viscosity = 3.6, melting point = 237.9 ° C.), and nylon 6 as aliphatic polyamide (A2) (“UBE Nylon 1030B” manufactured by Ube Industries, Ltd., relative viscosity = 4.4, melting point = 221.0 ° C.), and the resin composition for the core layer was mixed at a weight ratio of 60/40 (A1 / A2). Using a shaft extruder (screw diameter: 26 mm, L / D: 65), preliminary kneading was performed under the following conditions to obtain a kneaded product of the core layer resin composition.
<Preliminary kneading conditions for the resin composition for the core layer (biaxial extruder)>
・ Set temperature: 260 ° C (resin temperature is 275 ° C)
・ Screw rotation speed: 200rpm
・ Kneading time: 5 minutes

(Preparation of resin composition for coating layer)
On the other hand, as the resin composition for the coating layer, as the acid-modified polyolefin resin (B), maleic anhydride-modified polyethylene (“AMPLIFY TY1053H” manufactured by Dow Chemical, modification rate: 1.4% by weight), and polyolefin resin ( As C), high-density polyethylene (“Hi-Zex 6008B” manufactured by Prime Polymer Co., Ltd.) was prepared at a weight ratio of 1/2 (B / C).

(Kneaded product of core layer resin composition and melt kneaded resin composition for coating layer)
Next, the above-described resin composition for a coating layer and the kneaded product of the resin composition for a core layer obtained above were prepared at a weight ratio of 40/60 (core layer / coating layer).
The kneaded product of the resin composition for the core layer described above was melt-kneaded under the conditions shown below using a single-axis extruder for forming a core layer (screw diameter: 65 mm, L / D: 28).
<Melt-kneading conditions of the kneaded product of the core layer resin composition (single screw extruder)>
・ Set temperature: 250 ℃ (resin temperature is 265 ℃)
-Screw rotation speed: 30rpm
-Kneading time: 5 minutes On the other hand, the above-described resin composition for a coating layer was melt-kneaded under the conditions shown below using a single-screw extruder for forming a coating layer (screw diameter: 55 mm, L / D: 36).
<Melting and kneading conditions for coating layer resin composition (single screw extruder)>
・ Set temperature: 200 ℃ (resin temperature is 225 ℃)
-Screw rotation speed: 50rpm
-Kneading time: 5 minutes As described above, the kneaded product of the resin composition for the core layer and the coating layer resin composition are melt-kneaded and merged in the die, and the above-described uniaxial kneading for producing the multilayer pellets. Coextruded as a multi-layered strand formed with a coating layer covering the outer periphery of the core layer in an annular shape from the pores of the die attached to the tip of the extruder, the coextruded strand is water-cooled, and the weight is 1 with a pelletizer It cut | disconnected so that it might become about 20 mg per piece, it dried, and the multilayer pellet 1 of the manufacture example 1 was obtained.

(Production Example 2)
Same as Production Example 1 except that the weight ratio (A1 / A2) of the polyamide (A1) and the aliphatic polyamide (A2) was changed to 40/60 in the preliminary kneading of the resin composition for the core layer of Production Example 1. Thus, a multilayer pellet 2 of Production Example 2 was obtained.

(Production Example 3)
Same as Production Example 1, except that the weight ratio (A1 / A2) of the polyamide (A1) and the aliphatic polyamide (A2) was changed to 80/20 in the preliminary kneading of the resin composition for the core layer of Production Example 1. Thus, a multilayer pellet 3 of Production Example 3 was obtained.

(Production Example 4)
In the preliminary kneading of the resin composition for core layer of Production Example 1, among the pre-kneading conditions of the resin composition for core layer of Production Example 1, the set temperature was changed to 320 ° C. (resin temperature was 330 ° C.). The multilayer pellet 4 of Production Example 4 was obtained in the same manner as Production Example 1.

(Production Example 5)
Same as Production Example 1 except that the weight ratio (A1 / A2) of the polyamide (A1) and the aliphatic polyamide (A2) was changed to 20/80 in the preliminary kneading of the resin composition for the core layer of Production Example 1. Thus, the multilayer pellet 5 of Production Example 5 was obtained.

(Production Example 6)
A multi-layer pellet 6 of Production Example 6 was obtained in the same manner as Production Example 1 except that the aliphatic polyamide (A2) was not used in the preliminary kneading of the resin composition for core layer of Production Example 1.

(Production Example 7)
A multi-layer pellet 7 of Production Example 7 was obtained in the same manner as Production Example 1 except that the polyamide (A1) was not used in the preliminary kneading of the resin composition for the core layer of Production Example 1.

(Production Example 8)
A twin screw extruder was used for the production of the single layer pellet.
The weight ratio (A1 / A2) of the polyamide (A1) and the aliphatic polyamide (A2) used as the core layer resin composition in Production Example 1 was 60/40, and the resin composition for single layer pellets was Using a shaft extruder (screw diameter: 26 mm, L / D: 65), preliminary kneading was performed under the conditions shown below to obtain a kneaded product of the resin composition for single-layer pellets.
The weight ratio of the polyamide resin (A) and the olefin resin was 40/60 (polyamide resin (A) / olefin resin).
<Preliminary kneading conditions for resin composition for single layer pellet (biaxial extruder)>
・ Set temperature: 260 ° C (resin temperature is 275 ° C)
・ Screw rotation speed: 200rpm
-Kneading time: 5 minutes Next, the melt-kneaded product of the resin composition for single-layer pellets was extruded as a single-layer strand, the extruded strand was water-cooled, and cut with a pelletizer so that the weight was about 20 mg per piece. And dried to obtain a single-layer pellet 1 of Production Example 8.

(Production Example 9)
Polymetaxylylene adipamide which is polyamide (A1) used as the core layer resin composition in Production Example 1 (“MX Nylon 6121” manufactured by Mitsubishi Gas Chemical Co., Inc., relative viscosity = 3.6, melting point = 237.9 C.) itself was designated as single-layer pellet 2.

(Production Example 10)
Nylon 6 (UBE Nylon 1030B, manufactured by Ube Industries Ltd., relative viscosity = 4.4, melting point = 221.0 ° C.) itself, which is the aliphatic polyamide (A2) used as the core layer resin composition in Production Example 1 Was a single-layer pellet 3.

(Production Example 11)
In the preliminary kneading of the resin composition for single-layer pellets in Production Example 8, the polyamide (A1) and the aliphatic polyamide (A2) used as the core layer resin composition in Production Example 1 were not used, and the coating was conducted in Production Example 1. Only the acid-modified polyolefin resin (B) and polyolefin resin (C) used as the layer resin composition were used, except that the pre-kneading conditions of the resin composition for single layer pellets were changed to the conditions shown below. In the same manner as in Production Example 8, the single-layer pellet 4 of Production Example 11 was obtained.
<Preliminary kneading conditions for single layer pellet resin composition (single screw extruder for coating layer formation)>
・ Set temperature: 200 ℃ (resin temperature is 225 ℃)
・ Screw rotation speed: 200rpm
・ Kneading time: 5 minutes

The compositions of the multilayer pellets 1 to 7 obtained in Production Examples 1 to 7 and the compositions of the single-layer pellets 1 to 4 obtained in Production Examples 8 to 11 are shown in Tables 1 and 2, respectively. .
Furthermore, about the multilayer pellets 1-7 obtained by the said manufacture examples 1-7, by the method shown below, (1) The heat flux differential scanning calorimetry test was done and the measurement result was shown in Table 1. .

[Measuring method]
(1) Heat flux differential scanning calorimetry test In the multilayer pellets 1 to 7 obtained in Production Examples 1 to 7, only the core layer was sampled.
The temperature difference (ΔT ₁ ) between the two melting peaks derived from the polyamide-based resin (A) is determined using only the core layer as the measurement target sample, that is, the polyamide-based resin (A) constituting the core layer as the measurement target sample, and JIS K7121. In accordance with the method described in (1987), a DSC curve was obtained by a heat flux differential scanning calorimetry method. Specifically, the sample to be measured was placed in a container of a DSC apparatus, and a DSC curve was obtained when the temperature was raised from room temperature to 300 ° C. at a heating rate of 10 ° C./min without heat treatment. The multilayer pellets and the sample to be measured were stored under a nitrogen atmosphere in a desiccator so as not to be hydrolyzed while avoiding high temperature and high humidity conditions, and then vacuumed to store the water content at 1000 ppm or less.
Then, the melting peak temperature (T _H ) of the melting peak on the high temperature side and the melting peak temperature (T _L ) of the melting peak on the low temperature side are read from the obtained DSC curve, respectively, and the melting peak temperature (T _H ) of the melting peak and The temperature difference (ΔT ₁ ) between the melting peak and the melting peak temperature (T _L ) was determined.
On the other hand, the absolute value of the difference between the melting peak temperature _{(T A2)} of the melting peak temperature _{(T A1)} and the aliphatic polyamide (A2) of the polyamide _{(A1) (ΔT 2 = |} T A1 -T A2 |) is melted Using the polyamide (A1) before kneading and the aliphatic polyamide (A2) before melt kneading as samples to be measured, DSC curves were obtained by the same measuring method as described above.
Here, the melting peak temperature of the melting peak of the polyamide (A1) alone before the melt kneading is defined as “melting point (T _A1 ) of the polyamide ( _A1 )”, and the melting peak of the aliphatic polyamide (A2) alone before the melt kneading. The melting peak temperature was defined as “the melting point (T _A2 ) of the aliphatic polyamide ( _A2 )”.
The melting peak temperature of the melting point from DSC curves respectively obtained _{(T A1)} and melting point reading _{(T A2),} respectively, melting peak temperature _{(T A1)} and the aliphatic polyamide of the polyamide _{(A1) (A2) (T} A2 ) And a temperature difference (ΔT ₂ = | T _A1 −T _A2 |).
Furthermore, the absolute value of the difference (| ΔT ₁ −ΔT ₂ |) was determined from the temperature difference (ΔT ₁ ) and the absolute value of the difference (ΔT ₂ ).

(2) Relative Viscosity Measurement Method In Production Examples 1 to 7 of the multilayer pellet, the polyamide (A1) and the aliphatic polyamide (A2) used as the resin composition for the core layer are used as measurement target samples, and JIS K6920-2: Based on the method described in Appendix JA of 2009, 1 g of each was precisely weighed and dissolved in 100 ml of 96 mass% sulfuric acid at 20 to 30 ° C. with stirring.
After the sample to be measured is completely dissolved, immediately take 5 ml of the solution in a Cannon Fenceke viscometer (trade name: Canon Fenceke viscometer, manufactured by Tokyo Glass Instrument Co., Ltd.), and in a constant temperature bath at 25 ° C., 10 After leaving for a minute, the drop time (t) of the sample to be measured was measured. In addition, the dropping time (t ₀ ) of 96% by mass sulfuric acid itself was measured in the same manner. The relative viscosity, from the measured value of t and t _0, was calculated by the following equation (2).
(Formula 2) Relative viscosity = t / t ₀

(Example 1)
After producing the recycled resin pellet (Z), the container of Example 1 was manufactured using the obtained recycled resin pellet (Z). The detailed manufacturing method is described below.
Recycled resin pellet (Z)
The recycled resin pellet (Z) was obtained by mixing the multilayer pellet 1 obtained in Production Example 1 and high-density polyethylene (“Novatech HD HB111R” manufactured by Nippon Polyethylene Co., Ltd.) with a weight ratio of 20/80 (multilayer pellet 1 / High-density polyethylene) was dry blended, and the dry blend was supplied to an extruder of a blow molding machine (“YKC-080C” manufactured by YK Engineering). These were melt kneaded with an extruder at an extrusion set temperature of 220 ° C., a screw rotation speed of 90 rpm, and a kneading time of 5 minutes, and the melt kneaded product was extruded through an annular die to form a cylindrical parison. At this time, the temperature of the melt-kneaded product was 250 ° C. The parison in a softened state was sandwiched between split molds located directly under the die, and a blow pin was driven into the parison. Compressed air was blown into the space inside the parison from the blow pin, the parison was expanded, pressed against the inner surface of the mold cavity, and shaped according to the shape of the mold cavity. After cooling, the mold was opened, the container with burrs was taken out of the mold, and the burrs were excised to obtain a container. The recycled container (Z) was obtained by crushing the obtained container. In addition, as the metal mold | die used for manufacture of a container, the same thing as the metal mold | die used for manufacture of a recycled resin pellet was used.
The multilayer pellet 1 obtained in Production Example 1 as the multilayer pellet (X), the high-density polyethylene (“Novatech HD HB111R” manufactured by Nippon Polyethylene Co., Ltd.) as the high-density polyethylene (Y), and the regeneration obtained as described above Resin (Z) was dry blended at a weight ratio of 10/40/50 (X / Y / Z), and the dry blend was supplied to an extruder of a blow molding machine (“YKC-080C” manufactured by YK Engineering). . These were melt kneaded with an extruder at an extrusion set temperature of 220 ° C., a screw rotation speed of 90 rpm, and a kneading time of 5 minutes, and the melt kneaded product was extruded through an annular die to form a cylindrical parison. At this time, the temperature of the melt-kneaded product was 250 ° C. The parison in a softened state was sandwiched between split molds located directly under the die, and a blow pin was driven into the parison. Compressed air was blown into the space inside the parison from the blow pin, the parison was expanded, pressed against the inner surface of the mold cavity, and shaped according to the shape of the mold cavity. After cooling, the mold was opened, the container with burrs was taken out of the mold, and the burrs were cut away, whereby the container of Example 1 was obtained.
The obtained container has a weight of 460 g, a capacity of 0.0012 m ³ (1.2 L), an internal surface area of 0.1 m ² , and an average thickness of 3 mm, and has a cap portion that can be sealed with a screw cap. The part other than the opening of the plug part has a pinch-off part over the entire circumference.

(Example 2)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 2 obtained in Production Example 2, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 2 and the high-density polyethylene resin, and a container of Example 2 was produced in the same manner as Example 1.

(Example 3)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 3 obtained in Production Example 3, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 3 and the high-density polyethylene resin, and a container of Example 3 was produced in the same manner as in Example 1.

Example 4
In the melt kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 4 obtained in Production Example 4, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 4 and the high-density polyethylene resin, and a container of Example 4 was produced in the same manner as Example 1.

(Comparative Example 1)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 5 obtained in Production Example 5, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 5 and the high-density polyethylene resin, and a container of Comparative Example 1 was produced in the same manner as in Example 1.

(Comparative Example 2)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was replaced with the multilayer pellet 6 obtained in Production Example 6 and the multilayer pellet obtained in Production Example 7. The recycled resin (Z) of Example 1 was changed to a mixed multilayer pellet composed of 7 and the recycled resin based on a mixed resin of the multilayer multilayer pellet composed of the multilayer pellet 6 and the multilayer pellet 7 and a high density polyethylene resin. A container of Comparative Example 2 was produced in the same manner as in Example 1 except that the change was made.
Here, the mixed multilayer pellet is obtained by mixing the multilayer pellet 6 and the multilayer pellet 7 at a weight ratio of 60/40 (multilayer pellet 6 / multilayer pellet 7).

(Comparative Example 3)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was replaced with the single-layer pellet 1 obtained in Production Example 8 and the single-layer pellet obtained in Production Example 11. The recycled resin (Z) of Example 1 was changed to a mixed single layer pellet consisting of 4 and the recycled resin based on a mixed resin of a mixed single layer pellet consisting of the single layer pellet 1 and the single layer pellet 4 and a high density polyethylene resin. A container of Comparative Example 3 was produced in the same manner as in Example 1 except that the change was made.
Here, the mixed single-layer pellet is obtained by mixing the single-layer pellet 1 and the single-layer pellet 4 at a weight ratio of 40/60 (single-layer pellet 1 / single-layer pellet 4).

(Comparative Example 4)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1, the single-layer pellet 2 obtained in Production Example 9, and the single-layer pellet obtained in Production Example 11 The recycled resin (Z) of Example 1 was changed to a mixed single layer pellet consisting of 4 and the recycled resin based on a mixed resin of a mixed single layer pellet consisting of the single layer pellet 2 and the single layer pellet 4 and a high density polyethylene resin. A container of Comparative Example 4 was produced in the same manner as in Example 1 except that the change was made.
Here, the mixed single-layer pellet is obtained by mixing the single-layer pellet 2 and the single-layer pellet 4 at a weight ratio of 40/60 (single-layer pellet 2 / single-layer pellet 4).

(Comparative Example 5)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was replaced with the single-layer pellet 3 obtained in Production Example 10 and the single-layer pellet obtained in Production Example 11. The recycled resin (Z) of Example 1 was changed to a mixed single-layer pellet consisting of 4, and a recycled resin based on a mixed resin of a mixed single-layer pellet consisting of a single-layer pellet 3 and a single-layer pellet 4 and a high-density polyethylene resin. A container of Comparative Example 5 was produced in the same manner as in Example 1 except that the change was made.
Here, the mixed single-layer pellet is a mixture of the single-layer pellet 3 and the single-layer pellet 4 at a weight ratio of 40/60 (single-layer pellet 3 / single-layer pellet 4).

(Comparative Example 6)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 6 obtained in Production Example 6, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 6 and high-density polyethylene resin, and a container of Comparative Example 6 was produced in the same manner as Example 1.

(Comparative Example 7)
In the melt-kneading of the base resin composition of Example 1, the multilayer pellet 1 obtained in Production Example 1 was changed to the multilayer pellet 7 obtained in Production Example 7, and the recycled resin (Z ) Was changed to a recycled resin based on a mixed resin of the multilayer pellet 7 and the high-density polyethylene resin, and a container of Comparative Example 7 was produced in the same manner as in Example 1.

The containers prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were subjected to (2) fuel permeation test and (3) pressure strength test by the methods shown below, and the evaluation results are shown in Table 3. .
In addition, about the container produced in Examples 1-4, when the container was cut | disconnected and the iodine type tincture was applied to the cut surface and the polyamide-type resin (A) was dye | stained, a polyamide-type resin (A) was a high density polyethylene resin. It was confirmed that the layer was dispersed in (Y).

[Evaluation methods]
(2) Fuel permeation test In each container (weight: 460 g, capacity: 1.2 L, internal surface area: 0.1 m ² , and average thickness: 3 mm) prepared in Examples 1 to 4 and Comparative Examples 1 to 7, 0.5 L of fuel was filled from the opening of the stopper, and the stopper opening was sealed with a cap and left in an environment of 43 ° C. for 10 weeks.
Here, the fuel filled in the container is a mixture of isooctane / toluene / ethanol in a weight ratio of 45/45/10.
Thereafter, all the fuel is discharged from each container, and 1.2 L of new fuel is filled into each container from the opening of the stopper, and the total weight (W ₁ ) of each container is sealed with the stopper opening being sealed with a cap. It was measured. Each container filled with this fuel was allowed to stand for 10 days in an environment at a temperature of 40 ° C.
Then, the total weight (W ₂ ) of each container was measured, and the fuel permeation amount (g / m ² / day) was calculated from the measured weight change amount (W ₁ -W ₂ ) of each container.
From the result of the fuel permeation amount (g / m ² / day) calculated in this way, the quality of the fuel barrier property was evaluated according to the following criteria.
○ (Good): Fuel permeation amount is 3.0 g / m ² / day or less × (No): Fuel permeation amount exceeds 3.0 g / m ² / day

(3) Pressure strength test In each container (weight: 460 g, capacity: 1.2 L, internal surface area: 0.1 m ² , and average thickness: 3 mm) prepared in Examples 1 to 4 and Comparative Examples 1 to 7, A predetermined lid was attached to the container in a sealed state in which the mouth opening was sealed with a cap, and immersed in a 60 ° C. water tank.
Here, the predetermined lid refers to a lid having a function capable of injecting air in a sealed state in which the cap opening is sealed with a cap and applying pressure to the container, and having an air injection hole. Say.
Next, air was injected into the container from an air injection hole provided in a predetermined lid, the internal pressure of the container was maintained at 300 kPa, and the time until the container was broken was measured.
From the results of the time required for the container destruction measured in this way, the quality of the pressure strength was evaluated according to the following criteria.
○ (Good): Time required for container destruction is 2 hours or more × (No): Time required for container destruction is less than 2 hours

(Summary of results)
From the evaluation results shown in Table 3, the following can be understood.
The container of Comparative Example 1 was produced using the multilayer pellet 5 containing the polyamide (A1) and the aliphatic polyamide (A2) at a weight ratio (A1 / A2) of 20/80 as the base resin. As a result, it was found that although the desired pressure strength was obtained, the fuel barrier property was inferior to that of the container of the example and the fuel permeation amount was large.
The container of Comparative Example 2 was produced using a mixed multilayer pellet composed of a multilayer pellet 6 not containing an aliphatic polyamide (A2) and a multilayer pellet 7 not containing a polyamide (A1) as a base resin. As a result, it was found that although desired fuel barrier properties were obtained, the pressure strength was inferior to that of the container of the example.

The container of Comparative Example 3 was prepared using the single-layer pellet 1 containing the polyamide (A1) and the aliphatic polyamide (A2) at a weight ratio (A1 / A2) of 60/40 as the base resin. As a result, it was found that although desired fuel barrier properties were obtained, the pressure strength was inferior to that of the container of the example.
Although the container of the comparative example 4 was produced using the single layer pellet 2 which does not contain aliphatic polyamide (A2) as base material resin, although desired fuel barrier property is obtained, from the container of an Example Was also found to be inferior in pressure resistance.
Although the container of the comparative example 5 was produced using the single layer pellet 3 containing no polyamide (A1) as the base resin, a desired pressure strength was obtained, but the fuel barrier was higher than that of the container of the example. It was found that the amount of fuel permeation was large because of poor properties.

Although the container of the comparative example 6 was produced using the multilayer pellet 6 which does not contain aliphatic polyamide (A2) as base material resin, although desired fuel barrier property is obtained, from the container of an Example Was also found to be inferior in pressure resistance.
Although the container of the comparative example 7 was produced using the multilayer pellet 7 which does not contain polyamide (A1) as a base resin, a desired pressure strength was obtained, but the fuel barrier was higher than that of the container of the example. It was found that the amount of fuel permeation was large because of poor properties.

  On the other hand, each container of Examples 1 to 4 has a core layer and a coating layer constituting a multilayer pellet having a specific weight ratio of 20/80 to 80/20 (core layer / coating layer), In the polyamide-based resin (A) to be formed, multilayer pellets 1 to 4 containing polyamide (A1) and aliphatic polyamide (A2) at a specific weight ratio (A1 / A2) of 30/70 to 80/20 are included. It was found that each was produced by using it as a base resin, so that the fuel barrier property was excellent, the fuel permeation amount was small, and the pressure strength was also excellent.

Claims (7)

A multilayer pellet having a core layer containing a polyamide-based resin (A) and a coating layer containing an acid-modified polyolefin-based resin (B) covering the core layer,
The weight ratio of the core layer to the coating layer (core layer / coating layer) is 20/80 to 80/20,
Polyamide (A1) in which the polyamide-based resin (A) includes a dicarboxylic acid structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms and a diamine structural unit derived from metaxylylenediamine. And aliphatic polyamide (A2),
The multilayer pellet whose weight ratio (A1 / A2) of the said polyamide (A1) with respect to the said aliphatic polyamide (A2) is 30 / 70-80 / 20. The polyamide resin (A) is composed of the polyamide (A1) and the aliphatic polyamide (A2),
The polyamide (A1) is a polyamide comprising a dicarboxylic acid structural unit derived from adipic acid and a diamine structural unit derived from metaxylylenediamine,
The multilayer pellet according to claim 1, wherein the aliphatic polyamide (A2) is poly (caprolactam). Among the two melting peaks derived from the polyamide-based resin (A) in the DSC curve obtained by heat flux differential scanning calorimetry, the melting peak temperature ( _TH ) of the melting peak on the high temperature side and the melting peak of the melting peak on the low temperature side are melted. Difference from peak temperature (T _L ) (ΔT ₁ = T _H −T _L ), and melting peak temperature (T _A1 ) of the polyamide (A1) and melting peak temperature (T A2) of the aliphatic polyamide ( _A2 ) Absolute value (ΔT ₂ = | T _A1 −T _A2 |)
The multilayer pellet of Claim 1 or 2 which satisfy | fills the relationship of following formula 1.
(Formula 1) | ΔT ₁ −ΔT ₂ | ≦ 3 ° C. Of the two melting peaks derived from the polyamide resin (A), the difference (ΔT ₁ = T) between the melting peak temperature (T _H ) of the melting peak on the high temperature side and the melting peak temperature (T _L ) of the melting peak on the low temperature side. The multilayer pellet of Claim 3 whose _H - _TL ) is 10 degreeC or more and 18 degrees C or less.   The multilayer pellet of any one of Claims 1-4 whose content of the acid component originating in the acid-modified polyolefin resin (B) in the said coating layer is 0.05 to 5 weight%.   The multilayer pellet according to any one of claims 1 to 5, wherein a weight ratio (A1 / A2) of the polyamide (A1) to the aliphatic polyamide (A2) is 30/70 to 70/30. The multilayer pellet (X) according to any one of claims 1 to 6 and the high-density polyethylene resin (Y) are supplied to an extruder, and a melt-kneaded product obtained by melt-kneading them is formed. A method of manufacturing a container in which a softened parison is sandwiched between molds and blow molded,
The container manufacturing method which supplies a multilayer pellet (X) to an extruder so that the content rate of the polyamide-type resin (A) derived from the multilayer pellet (X) in the said container may be 1-10 weight%. .