JP2518564B2 - Multi-layer laminated structure material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer laminated structure in which a main material layer containing a polyethylene resin as a main component and an ethylene-vinyl acetate copolymer saponified material layer are laminated through at least an adhesive layer. Multi-layer packaging container, which can detect the presence or absence of an adhesive layer in a non-destructive state by using the ultrasonic reflection method, has excellent bayerability, and is extremely suitable for quality control or process control The present invention relates to a multilayer laminated structural material useful as a material, an automobile part, a part material for electronic / electrical devices.

[0002]

2. Description of the Related Art As widely known in the art, polyamide resins (PA), polyester resins, saponified products of ethylene-vinyl acetate copolymers (ethylene-vinyl alcohol copolymers, EVO
H), halogen-containing resins such as polyvinyl chloride resin (PVC) and polyvinylidene chloride resin (PVDC), non-polyolefin resins such as polycarbonate resin (PC), polymer alloys of polyphenylene oxide resin and PA, aluminum, iron, A multi-layer laminated structural material in which foils such as metals such as copper, tin and nickel and alloys containing these metals as main components (for example, stainless steel), synthetic resin films obtained by vacuum deposition of aluminum and silica are laminated It is widely used for various materials having functions such as barrier properties against water vapor and steam, improvement of appearance such as surface gloss, and coatability, such as various films, packaging containers, and industrial members.

Most of these multi-layer laminated structural materials are used as a main material layer from the viewpoints of economic efficiency, molding processability, sealing property, moisture resistance and water resistance, and the like. Polyethylene resin (linear low density or high density polyethylene resin), polypropylene resin,
Olefin-based copolymer resins and, if necessary, various fillers (eg calcium carbonate, talc,
It has a composition in combination with a composition containing mica, glass fiber, carbon fiber, and organic fiber).

By the way, since these polyolefin resins have a non-polar molecular structure, they are poor in adhesiveness, affinity and compatibility with the non-polyolefin resin and metallic materials, and the polyolefin resin is a polar monomer. By modifying (grafting polymerization), using a copolymer of an olefin (particularly ethylene) and a polar monomer, blending (blending) a polar resin, or treating by a chemical or physical means. It is widely practiced to impart the characteristics of In particular, in the case of molding by coextrusion method, it is well known that a so-called modified polyolefin resin graft-modified with a polar monomer is used as an adhesive material to form a multilayer laminate with the various materials described above (for example, Japanese Patent Publication Nos. 61-12782 and 55-3944
No. 8 and “'87 -2 <Packaging material report> Market trend and development direction of coextrusion multilayer film / sheet” (Sogo Packaging Co., Ltd., issued February 27, 1987) No. 28
5 to 293].

In this case, however, in a one-way container which does not receive a very strong impact in a relatively short period of time during the manufacturing process or distribution process of a product or a product, and which does not require a high level of performance such as interlayer adhesion strength. Although it is considered to be almost unnecessary, in containers and members that require long-term durability and high resistance to vibration and various impacts, the adhesive performance and durability of the adhesive are not only extremely important. It is more important and necessary to confirm the presence or absence of the adhesive layer that constitutes the structural material.

If there is a part where the adhesive layer is totally or partially missing in the multilayer laminated structure material for some reason, not only the mechanical properties may be deteriorated, but also in the long-term durability evaluation. , As contents
For example, in the case of liquids or gaseous substances, moisture and humidity from the outside air will stay in the missing parts, affecting not only the entire multilayer laminated structure material, but also impairing the appearance, resulting in commercial value and performance. Will be reduced. Therefore, if there is such a possibility, it is necessary to confirm that the adhesive layer in the multilayer laminated structure material is present over the entire area, but the adhesive layer should not be destroyed without destroying the multilayer laminated structure material. A method capable of easily and economically detecting the existence of a lumber layer has not yet been known.

As a method for confirming in advance that the adhesive layer of the multilayer laminated structure material is present, a part of the laminated structure material is cut and its cross section is subjected to various methods (for example, magnifying loupe and optical method). The method of observing and confirming with a microscope etc.) is generally practiced, but the sample used for this confirmation is no longer useful as a structural material and It is only presumed that the adhesive layer is present in the similarly manufactured multilayer laminated structural material, and it cannot be said to be a sufficiently reliable method.

On the other hand, in a relatively transparent multilayer laminated structure material, the presence of the adhesive layer can be confirmed by using optical analysis and analysis means, but this method is limited to a relatively thin material. Reliability and lack of reliability due to the influence of the molecular structure of the non-polyolefin resin material.

A method is also conceivable in which the adhesive layer is colored with an adhesive containing a coloring agent such as a pigment and the presence of the adhesive layer is confirmed visually or by using a color difference meter. It gives a remarkable limitation to the appearance of the product,
It cannot be applied when the outer layer is opaque and the layer thickness is large.

Therefore, the above-mentioned confirmation method and the amount of adhesive material used before and after molding the product are checked, and the calculated values calculated from the thickness, surface area and density of the adhesive layer in the laminated structural material are different. It is common practice to compare the estimated values with each other to substitute for the control of the presence of the adhesive layer. Further, there has been proposed a detection method in which a detection medium such as iron powder or glass fiber is mixed in a specific layer in the multi-layer extrusion molding and a magnetic sensor or an ultrasonic head is used, respectively (JP-A-63-2).
No. 60417), it is hard to say that the mixture of these is practical in terms of deterioration of adhesiveness, durability, flexibility, impact resistance and the like.

Therefore, in order to solve the above-mentioned problems of the prior art, the present inventors combined a detection method by ultrasonic waves and a main material layer and a bonding material layer containing a polyolefin resin as a main component in a multilayer laminated structure material. As a result of various searches regarding the above, by providing a difference in acoustic characteristics between the main material layer and the adhesive layer to a certain level or more, nondestructive detection of the adhesive layer, which has hitherto been unknown, can be performed by the ultrasonic reflection method. Becomes possible,
It is an object of the present invention to provide a multi-layer laminated structure material in which even if a part of the adhesive material layer is missing, there is no missing part.

[0012]

Means and Action for Solving the Problems The present inventors have
As a result of intensive research to solve this problem, it was found that the above problems can be solved by considering the difference in acoustic impedance due to ultrasonic waves between the main material layer and the adhesive layer having a special composition, and the present invention Was completed. That is, the gist of the present invention is a layered structure in which a main material layer containing a polyethylene resin as a main component is laminated on the outside and a saponified layer of an ethylene-vinyl acetate copolymer is laminated on the inside through at least an adhesive layer. And (A) a density of 0.930 g / cm ³ or more, the number of short chain branches per 1000 carbon atoms in the main chain is 20 or less, and the melt flow rate is But
0.01 g / 10 minutes or more at a high density polyethylene resin, density 0.910 g / cm ³ or more 0.935 g / cm ³
Below, melt flow rate 0.1 to 50 g / 10 minutes, melting point by differential scanning calorimeter (hereinafter referred to as DSC) 11
Linear low density polyethylene resin having 5 to 130 ° C and 5 to 30 short chain branches per 1000 carbon atoms in the main chain, and unsaturated carboxylic acid and / or its derivative grafted on the high density polyethylene resin A resin selected from the group consisting of a modified high-density polyethylene resin obtained by subjecting the linear low-density polyethylene resin and a modified linear low-density polyethylene resin obtained by grafting an unsaturated carboxylic acid and / or a derivative thereof to the linear low-density polyethylene resin. The modified high-density polyethylene resin and / or the modified linear low-density polyethylene resin is 0.1 to 90% by weight of the polyethylene resin, and (B) the density is 0.890 g / cm ³ or more and 0.910 g. / cm less than ^3, the number of branches of the short chain of 1000 per carbon atoms in the main chain 18 to 60
Individual, melt flow rate 0.1 to 30 g / 10 minutes, DS
Contains 40 to 5% by weight of a linear ultra-low density polyethylene resin having a melting point of 110 to 125 ° C. according to C and a density of 0.92.
5 g / cm ³ or more, and the proportion of the grafted unsaturated carboxylic acid and / or its derivative is 0.001 to 5.0% by weight.
The difference in acoustic impedance between the main material layer and the adhesive layer measured by using an ultrasonic wave of 20 to 25 MHz is 8.5 × 10 ⁻³ g / cm ² · μsec or more. The present invention provides a multi-layer laminated structure material characterized by:

The multi-layer laminated structure material of the present invention will be specifically described below. The multilayer laminated structural material of the present invention, as described above,
It has a layered structure in which a main material layer containing a polyethylene resin as a main component is laminated on the outer side and a saponified layer of an ethylene-vinyl acetate copolymer is laminated on the inner side through at least an adhesive layer.

Main Material Layer Examples of the polyethylene-based resin used as a main component in the main material layer in the present invention include ethylene homopolymers and copolymers of ethylene and other α-olefins. Here, the α-olefin is generally an olefin having 3 to 12 carbon atoms (preferably 3 to 8 carbon atoms). Typical α-
Examples of the olefin include propylene, butene-1, hexene-1, octene-1,4-methylpentene-1.

For the main material layer, only the above polyethylene resin may be used, and a small amount (at most 20% by weight) of an elastomer or other synthetic resin which can be uniformly mixed with the polyethylene resin used. You may mix. Elastomers that can be used include polyisobutylene, ethylene-
Propylene copolymer rubber (EPR), ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), block or random styrene-butadiene copolymer rubber (SB)
R) and the like. Also, as other synthetic resins,
Examples thereof include copolymers of ethylene and vinyl acetate, methyl ester of acrylic acid or methacrylic acid, ethyl ester, butyl ester and the like. Furthermore, PA (polyamide resin), polyester resin, EVO within the range that the basic characteristics of the main component polyethylene resin are not significantly impaired.
Different polymers such as H and PVC may be blended.

In the main material layer, at most 30% by weight of the filler generally added to the above polyolefin resin may be added. As the filler, calcium carbonate, talc, mica, glass fiber, carbon fiber, metal fiber, other inorganic fiber and organic polymer fiber (for example,
Polyester fiber, polyamide fiber).

In the present invention, when the polyethylene resin is blended with an elastomer, another synthetic resin and a filler, the blending amount of these is 40% by weight at most. If the total blending amount exceeds 40% by weight, there is a disadvantage that molding processability, impact resistance, gasoline resistance and the like are deteriorated.

In the multilayer laminated structure material of the present invention, the melt flow rate of the polyethylene resin as the main component of the main material layer (measured according to JIS-K7210 under the condition of 4 in Table 1 is 4, hereinafter referred to as "MFR"). ) Is not particularly limited, but is generally 0.00 in terms of moldability.
It is 5 g / 10 minutes or more, preferably 0.01 g / 10 minutes or more, and particularly preferably 0.02 g / 10 minutes or more.

Among the polyethylene resins, preferred ones have a density of 0.930 g / cm ³ or more (preferably 0.9).
35 g / cm ³ or more) of ethylene homopolymers and ethylene-α-olefin copolymers. Further, these ethylene homopolymers and copolymers of ethylene and α-olefin have a density of 0.
It is obtained by blending low-density polyethylene of less than 930 g / cm ³ and a copolymer of ethylene and a monomer other than α-olefin, a propylene homopolymer, a copolymer of propylene and ethylene or another α-olefin, and the like. the density of the ethylene polymer composition is 0.930 g / cm ³ or more (preferably, 0.935 g / cm ³ or higher) may be used in preference to those. Among these ethylene-based polymers, medium to high density polyethylene having a density of 0.935 g / cm ³ or more is particularly preferable.

Saponified Layer of Ethylene-Vinyl Acetate Copolymer Saponified product of ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) which can be used is, for example, ethylene-
It can be produced by saponifying a vinyl acetate copolymer (EVA) with an alkali or the like. The copolymerization ratio of ethylene in EVA is usually 20 to 80 mol%, and particularly preferably 25 to 75 mol%. If the copolymerization ratio of ethylene is less than 20 mol%, the molding processability is poor. On the other hand, if it exceeds 80 mol%, the obtained multilayer laminated structural material is unsatisfactory in terms of gas resistance and barrier properties against liquid permeation. is there. The degree of saponification is not particularly specified, but it is usually 90% or more from the viewpoint of barrier property, and particularly 9%.
5% or more is preferable. If the degree of saponification is less than 90%, the barrier property of the similarly obtained multilayer laminated structure material is not sufficient. The molecular weight of this EVOH is not particularly limited, but it is defined in JIS-K7210 condition 4 (190 ° C, 2160).
(g load) method, the melt flow index (MFI) is 0.5 to 20 g / 10 minutes, and 1 to 10
It is preferably g / 10 minutes. In addition, EVOH is
One type may be used, or two or more types may be used in combination. Furthermore, a polyamide resin or a thermoplastic polyvinyl alcohol having compatibility with EVOH can be melt-molded without significantly impairing the barrier property. Then EV
It can be used by blending with OH, and in particular, the latter method can obtain higher gas-liquid barrier property.

Adhesive Layer In the multilayer laminated structure material of the present invention, the adhesive layer is (A)
Density is 0.930 g / cm ³ or more, main chain carbon number is 1000
High-density polyethylene resin with 20 or less short chain branches per unit and melt flow rate of 0.01 g / 10 min or more, density of 0.910 g / cm ³ or more and 0.935 g / cm
Less than ³ , melt flow rate 0.1 to 50 g / 10 minutes,
Melting point by DSC is 115 to 130 ° C, carbon number of main chain is 1
A linear low-density polyethylene resin having 5 to 30 short-chain branches per 000, and a modified high-density polyethylene resin obtained by grafting an unsaturated carboxylic acid and / or a derivative thereof onto the high-density polyethylene resin. And a resin selected from the group consisting of a modified linear low density polyethylene resin obtained by grafting an unsaturated carboxylic acid and / or a derivative thereof onto the linear low density polyethylene resin, the modified high density polyethylene resin and / Or modified linear low density polyethylene resin polyethylene resin containing 0.1% by weight or more 60-95
% By weight and (B) density 0.890 g / cm ³ or more 0.91
Less than 0 g / cm ³ , the number of short chain branches per 1000 carbon atoms in the main chain is 18 to 60, and the melt flow rate is 0.1 to
30 g / 10 min, melting point by DSC: 110-125 ° C
Which contains 40 to 5% by weight of a linear ultra low density polyethylene resin having a density of 0.925 g / cm ³ or more, and a proportion of a grafted unsaturated carboxylic acid and / or a derivative thereof.
The resin composition is 0.001 to 5.0% by weight.

Hereinafter, "modified" refers to a grafted product of an unsaturated carboxylic acid and / or its derivative,
"Unmodified" refers to those that have not been grafted.

The high-density polyethylene resin as the component (A) and the high-density polyethylene resin for the modified high-density polyethylene resin constituting the adhesive layer have a density of 0.930 g / cm.
^{When the number is 3} or more, the number of short chain branches per 1000 carbon atoms in the main chain is at most 20.

The density of this high density polyethylene resin is 0.
933 g / cm ³ or more is preferable, and particularly 0.935 g / c
m ³ or more is preferable. The use of high-density polyethylene resin is superior in that it improves the rigidity, heat resistance, fuel oil resistance, surface hardness, etc. of the obtained product.

Further, the MFR is 0.01 g / 10 minutes or more, preferably 0.015 g / 10 minutes or more, and more preferably 0.05 g / 10 minutes or more.
02g / 10 minutes or more is suitable. MFR is 0.01g /
If it is less than 10 minutes, the moldability is poor. Further, the upper limit is not particularly limited, but is usually 50 g / 10 minutes,
It is particularly preferably 35 g / 10 minutes or less.

In particular, when the MFR is less than 0.01 g / 10 min, the MFR of the obtained high density polyethylene resin grafted is generally that of the high density polyethylene resin used for grafting, although it depends on the graft modification conditions. It becomes even lower than MFR, the molding processability is lowered, and the compatibility when producing a mixture with a high density polyethylene resin which is not grafted is remarkably lowered, and a uniform composition cannot be obtained. Therefore, the MFR of the modified polyethylene resin is generally desired to be 0.05 g / 10 minutes or more. Particularly, 0.1 g / 10 or more is preferable.

The high-density polyethylene resin is ethylene alone or ethylene and α-olefin having 3 to 12 carbon atoms (preferably 3 to 8 carbon atoms) in the presence of a so-called Phillips catalyst or Ziegler catalyst. It is obtained by homopolymerization or copolymerization, and is generally produced at a pressure of normal pressure to 100 kg / cm ² (medium or low pressure method polymerization). Preferred examples of the α-olefin include propylene, butene-1, hexene-1,4-methylpentene-1 and octene-1.
Is mentioned. The copolymerization ratio is 6.5% by weight or less, and particularly preferably 6.0% by weight or less. The high-density polyethylene resins may be used alone or in combination of two or more kinds.

The linear low-density polyethylene resin used in the same manner as the high-density polyethylene resin is manufactured industrially and is particularly excellent in environmental stress crack resistance, transparency, heat sealability, brittleness resistance, low temperature characteristics and the like. Therefore, it is used in many fields (for example, packaging materials such as films and industrial materials such as pulp). This linear low density polyethylene resin is produced by copolymerizing ethylene and the α-olefin by a gas phase method, a solution method or a slurry method using a so-called Ziegler catalyst. .

The linear low density polyethylene resin has a density of 0.
910 g / cm ³ or more and less than 0.935 g / cm ³ ,
Is preferably less than 0.912 g / cm ³ or more 0.935 g / cm ^3, especially 0.913 g / cm ³ or more 0.935 g / cm ³
Less than is preferred. In addition, MFR is 0.1-50g / 10
Minutes, 0.2-40 g / 10 minutes is desirable, especially
0.2-30 g / 10 minutes is suitable. If the MFR of the linear low-density polyethylene resin is less than 0.1 g / 10 minutes, the moldability will be poor. On the other hand, if it exceeds 50 kg / 10 minutes,
The resulting composition has poor mechanical strength.

Further, the linear low density polyethylene resin D
The melting point by SC is 115 to 130 ° C, 118 to 1
30 ° C. is preferable, and 118 to 125 ° C. is particularly preferable. When the melting point by the DSC method is lower than 115 ° C,
Poor long-term solvent resistance at high temperatures. On the other hand, 130 ° C
When it exceeds, the density exceeds the upper limit of the above range.

The number of short chain branches per 1000 carbon atoms in the main chain of the linear low density polyethylene resin is 5 to 30, and preferably 5 to 25. If the number of branches of the short chain per 1000 carbon atoms in the main chain is less than the lower limit or more than the upper limit, the uniformity of the composition of the present invention becomes insufficient, which is not preferable. That is, the number of carbon atoms in the main chain is 1000
When the number of branches per unit is out of the above range, a composition using a linear low-density polyethylene resin is used, particularly when evaluating long-term solvent resistance (for example, fuel oil resistance), tensile elongation In addition to the large decrease in physical properties, under the condition that heat resistance (specifically, durability test in an atmosphere of 100 ° C. or higher) is added, the physical properties further decrease. It is thought that this is due to the non-uniformity of.

The modified polyethylene resin (ie, modified high-density polyethylene resin and modified linear low-density polyethylene resin) used as the component (A) in the present invention is the above-mentioned high-density polyethylene resin and / or linear low-density polyethylene resin. It is obtained by grafting an unsaturated carboxylic acid and / or its derivative described below to a polyethylene resin. This grafting reaction is carried out in the presence of a radical initiator, and in that case, the following synthetic resin or elastomer (rubber) having affinity with the high-density polyethylene resin and linear low-density polyethylene resin to be grafted is present. Good.

The unsaturated carboxylic acid and its derivative used in the graft treatment in the present invention include monobasic unsaturated carboxylic acid and dibasic unsaturated carboxylic acid, and their metal salts, amides, imides, esters and anhydrides. Is mentioned. Among these, the monobasic unsaturated carboxylic acid and its derivative are generally preferably those having 20 or less carbon atoms, and more preferably those having 15 or less carbon atoms. Further, as the dibasic unsaturated carboxylic acid and its derivative, those having 30 or less carbon atoms are generally preferable, and those having 25 or less carbon atoms are more preferable. Representative examples of these unsaturated carboxylic acids and their derivatives are described in JP-A-62-10107. Among these unsaturated carboxylic acids and their derivatives, acrylic acid, methacrylic acid, maleic acid and their anhydrides, 5-
Norbornene-2,3-dicarboxylic acid and its anhydride and glycidyl methacrylate are preferable, and maleic anhydride and 5-norbornene anhydride are particularly preferable.

The total amount of the unsaturated carboxylic acid and its derivative used for the graft modification is generally 0.01 to 5.0 parts by weight, and 0.01 to 3 parts by weight, based on 100 parts by weight of the polyethylene resin to be grafted. 0.0 parts by weight is preferable, and 0.02 is particularly preferable.
Approximately 2.0 parts by weight is preferred. When the proportion of the unsaturated carboxylic acid and its derivative is less than 0.01 parts by weight as the total amount of them, the graft modification becomes insufficient and there is a problem in the affinity or the adhesiveness which is the object of the present invention. On the other hand, 5.
If it exceeds 0 parts by weight, the resulting graft-modified polyethylene resin may cause gelation, coloring, deterioration, and the like, and improvement of the performance of the present invention cannot be observed.

Further, as the radical initiator, those having a decomposition temperature of one minute half-life of 100 ° C. or higher can be usually used, preferably 103 ° C. or higher, and particularly preferably 105 ° C. or higher. is there. Suitable radical initiators include dicumyl peroxide; benzoyl peroxide; di-tertiary-butyl peroxide; 2,5-dimethyl-2,5-
Di (tertiary-butylperoxy) hexane; 2,5-dimethyl-2,5-di (tertiary-butylperoxy) hexane-3; Lauroyl peroxide; Organic peroxidation such as tertiary-butylperoxybenzoate Things can be mentioned. The proportion of the radical initiator is usually 0.001 to 1.0 part by weight, preferably 0.005 to 1.0 part by weight, and more preferably 0.000 part by weight, relative to 100 parts by weight of the polyethylene resin to be grafted.
5 to 0.5 parts by weight is preferred. The ratio of radical initiator
If it is less than 0.001 part by weight, the effect of graft modification is poorly exhibited, and it not only takes a long time to completely carry out graft modification, but also unreacted substances are mixed. On the other hand, if it exceeds 1.0 part by weight, excessive decomposition or crosslinking reaction occurs, which is not preferable.

As the olefin resin which can coexist during the above graft reaction, a high-pressure low-density polyethylene resin, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, Examples thereof include copolymers of ethylene and other vinyl monomers such as ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer. Further, as the elastomer, ethylene-propylene copolymer rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butene-1 copolymer rubber and other ethylene-α-olefin copolymer rubber, polyisobutylene rubber, polyurethane rubber , Synthetic rubber such as styrene-butadiene copolymer rubber and polybutadiene rubber, and natural rubber. These are generally 10% by weight or less, particularly 5.0% by weight, in the polyethylene resin to be grafted.
It is preferably used in the following amounts. When the total amount of the olefin resin and / or the elastomer in the total amount of the high-density polyethylene resin and / or the linear low-density polyethylene resin exceeds 10% by weight, the high-density polyethylene resin and / or the linear low-density resin It may impair the basic properties of polyethylene resin.

The modified polyethylene resin (ie, modified high-density polyethylene resin and modified linear low-density polyethylene resin) used as the component (A) in the present invention is the above-mentioned high-density polyethylene resin and / or linear low-density resin. It is obtained by grafting an unsaturated carboxylic acid and / or its derivative described below to a polyethylene resin. This grafting reaction is carried out in the presence of a radical initiator, and in that case, the following synthetic resin or elastomer (rubber) having affinity with the high-density polyethylene resin and linear low-density polyethylene resin to be grafted is present. Good. This reaction is carried out by a known method, for example, JP-A-62-10107 and 61-132345.
It can be carried out by the method described in Japanese Patent Publication.

The reaction is carried out by a method of kneading a high density polyethylene resin or the like processed in a molten state using an extruder, a Banbury mixer, a kneader, etc., a high density polyethylene resin, a linear low density polyethylene resin or the like in an appropriate solvent. Examples of the method include a solution method in which a polymer is dissolved, a slurry method in which particles of a polymer such as a high-density polyethylene resin are suspended, or a gas phase graft method.

The reaction temperature is appropriately selected in consideration of deterioration of polymers such as high-density polyethylene resin and linear low-density polyethylene resin, decomposition of unsaturated carboxylic acid and its derivative, decomposition temperature of radical initiator used, and the like. However, taking the method of kneading in the molten state as an example, the temperature is usually 100 to 350 ° C, preferably 150 to 300 ° C. Especially, 180 to 300 ° C. is preferable.

The modified high-density polyethylene resin and the modified linear low-density polyethylene resin of the present invention are, of course, manufactured in this manner, but for the purpose of improving their performance, they are described in JP-A-62-10107. As is well known in the art, for example, a method of treating with an epoxy compound or a polyfunctional compound containing an amino group or a hydroxyl group at the time of or after graft modification, and by heating or washing the unreacted monomer (unsaturated carboxylic acid). (Or its derivative) and various components produced as by-products can be adopted.

In the multilayer laminated structure material of the present invention, the adhesive layer must further contain a linear ultra-low density polyethylene resin as the component (B). The production method of this linear ultra-low density polyethylene resin is widely known, and has been industrially produced by the improvement of the slurry polymerization method or the gas phase polymerization method in recent years and is widely used. .

Accordingly, a low crystallinity ethylene-α-olefin random copolymer having a crystallinity of several% to about 30% obtained by polymerizing using a conventionally known vanadium catalyst system (density 0 .86 to 0.91 g / cm ³ )
Unlike JP-A-57-68306 and 59, for example.
It is a linear ultra-low density polyethylene resin produced by a slurry method or a gas phase method using a stereoregular catalyst (so-called Ziegler catalyst) as described in JP-A-23011 and JP-A-61-109805.

The component (B) linear ultra-low density polyethylene resin has a density of 0.890 g / cm ³ or more and 0.910 g / c.
m is less than ^3, and MFR of 0.1 to 30 g / 10 min, and a melting point of 110-125 ° C. by DSC, yet 18 is the number of branches of the short chain of 1000 per carbon atoms in the main chain It is a linear ultra-low density polyethylene resin of 60 pieces.

In the present invention, the resin has a density of 0.890.
If it is less than g / cm ³ , there is a problem in fuel oil resistance of the resulting composition. On the other hand, if it exceeds 0.910 g / cm ³ ,
The resulting composition is insufficient in impact resistance. From these things, the density of 0.892 to 0.910 g / cm ³ is preferable. Further, when the MFR of the resin is less than 0.1 g / 10 minutes, it is not preferable in terms of moldability and processability, and 30 g
If it exceeds / 10 minutes, there is a problem in impact resistance. From these facts, the MFR is preferably 0.1 to 10 g / 10 minutes, and particularly preferably 0.2 to 8.0 g / 10 minutes.

Further, DSC (a sample of about 5 mg was weighed, set in a DSC measuring device, heated to 200 ° C. from room temperature at a heating rate of 10 ° C./min, and then held at that temperature for 5 minutes. Then, the temperature is lowered to room temperature at a cooling rate of 10 ° C./min, and the melting point is the peak temperature of the maximum endothermic region when the temperature is further raised at a heating rate). is there. Especially 112 ~
The thing of 125 degreeC is preferable. When the melting point is lower than 110 ° C., the heat resistance of the resulting composition is insufficient, and
If it is higher than 5 ° C, the effect of improving impact resistance is poor.

The number of short chain branches per 1000 carbon atoms in the main chain of the resin is 18 to 60, preferably 18 to 50, and more preferably 20 to 50. If the number of short chain branches per 1,000 carbon atoms in the main chain is less than 18, there is a problem in the impact resistance of the resulting multilayer laminated structure material, and if it exceeds 60, the fuel oil resistance is significantly poor. . Here, the short chain is substantially composed of an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms).

In addition, from the viewpoint of improving the impact resistance, the initial tensile elastic modulus of the polyethylene resin is 2 × 10 ³ kg.
f / cm ² or less (preferably 1.5 × 10 ³ kgf / c
m ² or less) is preferable. Such a polyethylene resin is prepared by using a Ziegler type catalyst and ethylene and the α-
It is obtained by copolymerizing with an olefin.

In the present invention, the resin composition constituting the adhesive layer contains 0.1% of the modified high-density polyethylene resin and / or the modified linear low-density polyethylene resin in the component (A).
It is necessary to contain at least wt%. When the content of the fully modified polyethylene resin is less than 0.1% by weight, it is not possible to obtain an adhesive material satisfying the affinity or adhesiveness with the resin material or the metal material, which is the object of the present invention. The content of the modified polyethylene resin is preferably 1.0% by weight or more, and particularly preferably 2.5% by weight.

In the present invention, the resin composition constituting the adhesive layer must contain 5.0 to 40% by weight of the linear ultra-low density polyethylene resin which is the component (B). If the proportion of the linear ultra-low density polyethylene resin in the composition is less than 5.0% by weight, the resulting laminated structural material is inferior in impact resistance, and if it exceeds 40% by weight, the fuel oil resistance (particularly 4% by weight) is obtained.
(Fuel oil resistance at 0 ° C.) is remarkably lowered, which is not preferable. The content of the linear ultra low density polyethylene resin is preferably 5.0 to 38% by weight, and particularly 7.0 to 38% by weight.
% By weight is preferred.

In the present invention, the resin composition constituting the adhesive layer is, in addition to the above-mentioned components (A) and (B), an unmodified high density polyethylene resin and / or an unmodified linear low density polyethylene resin. May be included. That is, generally, when a polymer (a high density polyethylene resin or a linear low density polyethylene resin in the case of the present invention) is graft-modified with a monomer (an unsaturated carboxylic acid or a derivative thereof in the case of the present invention), all polymers are Is difficult to graft, and there is some ungrafted polymer. In the present invention, the non-grafted high-density polyethylene resin or linear low-density polyethylene resin may be used as it is without being separated. Further, an unmodified high-density polyethylene resin and / or linear low-density polyethylene resin which has not been graft-treated may be blended.

When the unmodified linear low-density polyethylene resin is added, the amount thereof used is preferably 2.5 to 75% by weight, and particularly preferably 5.0 to 60% by weight in the component (A).
When the composition ratio of the unmodified linear low-density polyethylene resin is less than 2.5% by weight, the uniformity of the composition in all compositions is poor. On the other hand, if it exceeds 75% by weight, the heat resistance and the long-term fuel oil resistance at high temperatures are poor.

When the unmodified high-density polyethylene resin is added, the amount used is preferably 99.9% by weight or less, and particularly preferably 99.0% by weight or less in the component (A). If the composition ratio of the unmodified high-density polyethylene resin exceeds 99.9% by weight, the adhesiveness will be insufficient.

In the resin composition constituting the adhesive layer in the present invention, a part of all the composition components may be mixed in advance and the remaining composition components may be mixed, or all the composition components may be simultaneously mixed. Good. In any case, the ratio of the grafted monomer (unsaturated carboxylic acid and / or its derivative) in the adhesive in the present invention is 0 as the total amount thereof.
001 to 5.0% by weight, preferably 0.01 to 2.0% by weight, and more preferably 0.02 to 1.0% by weight. When the proportion of the grafted monomers in the adhesive material is less than 0.001% by weight as the total amount thereof, various effects of the present invention cannot be sufficiently exhibited. On the other hand, 5.0% by weight
Even if it exceeds, the effect of the present invention cannot be further improved.

In the present invention, the composition of the resin composition constituting the adhesive layer satisfies the above-mentioned conditions, the density of the adhesive is 0.925 g / cm ³ or more, and 20 to
The difference in acoustic impedance between the main material layer and the adhesive layer measured using 25 MHz ultrasonic waves is 8.5 × 10 ⁻³ g / cm 2.
It is necessary to select it so that it is at least ² μsec. The density of the adhesive is required 0.925 g / cm ³ or more, in particular 0.926 g / cm ³ or more. When the density of the adhesive is less than 0.925 g / cm ³ , long-term solvent resistance is not good.

The acoustic impedance of the adhesive layer [hereinafter referred to as "Z ₁ "] is 1.980 × 10 ^-1 g / cm ^2.
・ It is more than μsec and 1.982 × 10 ^-1 g / cm ²・
μsec or more is desirable, especially 1.984 × 10 ⁻¹ g
/ Cm ² · μsec or more is preferable. Z ₁ is 1.980
If it is less than × 10 ⁻¹ g / cm ² · μsec, fuel oil resistance and heat resistance are insufficient.

On the other hand, the acoustic impedance (Z ₀ ) of the main material layer is preferably about 2.00 × 10 ⁻¹ g / cm ² · μsec or more, and 2.10 × 10 ⁻¹ g / cm ² · μsec or more. Desirably, especially 2.20 × 10 ⁻¹ g / cm ² · μ
Sec or more is preferable.

However, in order to detect the presence or absence of the adhesive layer by the non-destructive method, the difference | Z ₀ -Z ₁ | in the acoustic impedance between the main material layer and the adhesive layer is 8. 5 x 1
0 ⁻³ g / cm ² · μsec or more, 9.0 × 10 ⁻³ g
/ Cm ² · μsec or more is desirable, especially 9.5 × 1
It is preferably 0 ⁻³ g / cm ² · μsec or more. That is, for example, Z ₀ is 2.20 × 10 ⁻¹ g / cm ² · μse
In case of c, Z ₁ is 2.115 × 10 ⁻¹ g / cm ² · μs
ec or less. If the difference in acoustic impedance between the main material layer and the adhesive layer is less than 8.5 × 10 ⁻³ g / cm ² · μsec, it is impossible to detect the existence of the adhesive layer by ultrasonic waves in a non-destructive state. Becomes

In producing each composition of the present invention, an antioxidant, a heat stabilizer, an ultraviolet absorber, which is generally used in the field of polyolefin resins in a range that does not substantially impair the effects of the composition, Additives such as lubricants, antistatic agents and pigments (colorants) can be added.

As the mixing method for producing the composition, various mixing methods generally used in the field of synthetic resins, that is, a method of dry blending using a mixer such as a tumbler or a Henschel mixer, an extruder, Any method of melt kneading using a kneader such as a kneader, a Banbury mixer and a roll can be used. At this time, a more uniform composition can be obtained by carrying out two or more of these mixing methods (for example, a method of dry-blending in advance and further melt-kneading the resulting mixture).

The multi-layer laminated structure material of the present invention can be manufactured by laminating the main material and EVOH via the above-mentioned adhesive by a method generally used in the field of synthetic resins. The lamination is a method of co-extruding a main material, an adhesive and EVOH using three or more extruders (for example, multi-layer blow, co-extrusion inflation, T-die film molding), EVOH as a base material, and Co-press the main material and adhesive material at the same time to coat (coating or lamination)
It can be carried out by the method of heating or pressure bonding. Further, there is a method in which each of them is separately formed into a film or a sheet, and these are heated and pressed.

As the constitution of the multilayer laminated structure material of the present invention,
If A is the main material layer, B is the adhesive material layer, and C is EVOH, A
/ B / C, A / B / C / B, A / B / C / B / A, or a repeating structure of these structures, and a barrier layer D
Then, the D layer may be interposed between the A layer and the B layer.
In addition, in order to effectively use the burr generated during product molding, generally, this is finely pulverized, and if necessary, the composition is homogenized with an extruder or the like, melt-kneaded, and mainly recycled into the main material layer, Alternatively, a recycle layer E is newly provided and, for example, A / E / B / C, E / A / B / C, or the like, has a layer structure that is placed outside the A layer or between the A layer and the B layer.

Whether it is melt-kneaded to produce the adhesive material or laminated to produce a multi-layer laminated structure material, both are at a temperature at which various polyethylene resins, synthetic resins, elastomers and EVOH are melted. Need to be implemented. However, when carried out at elevated temperatures, they can decompose thermally. For the above reasons, it is generally carried out at 170 to 280 ° C (preferably 190 to 250 ° C).

[0063]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. Various modified polyethylene resins used as the adhesive component in the examples and comparative examples were prepared as follows. The polyethylene resin is abbreviated as PE.

The modified PE (a) powder HDPE (a) having a density of 0.952 g / cm ³ and an MFR of 0.93 g / 10 min was prepared by adding 2,2 as a radical initiator.
0.012 parts by weight of 5-dimethyl-2,5-t-butylperoxyhexane was added, and after dry blending for 2 minutes with a Henschel mixer, maleic anhydride (hereinafter referred to as MA
(Abbreviated as H) is added in an amount of 0.375 parts by weight, and dry blending is further performed for 2 minutes by a Henschel mixer, and the mixture is melt-kneaded at a resin temperature of 257 ° C. and pelletized. The grafted MAH content of this product was 0.33% by weight by infrared spectroscopy.
Met.

Modified PE (b) A powdered HDPE (b) having a density of 0.945 g / cm ³ and an MFR of 0.44 g / 10 min.
Add 0.012 parts by weight of 5-dimethyl-2,5-t-butylperoxyhexane and dry blend for 2 minutes with a Henschel mixer, then add 0.375 parts by weight of MAH to this and dry blend with a Henschel mixer for another 2 minutes. Then, the mixture was melt-kneaded at a resin temperature of 260 ° C. and pelletized. The graft MAH content of this product was 0.32% by weight by infrared spectroscopy.

Modified PE (c) Density 0.925 g / cm ³ , MFR = 0.78 g / 10 min,
A linear low-density PE (hereinafter abbreviated as LLDPE) (c) having a melting point of 120.5 ° C. and a branching number of 9.5 / 1000C was added to 2,5-dimethyl-2,5-t-as a radical initiator. Add 0.012 parts by weight of butylperoxyhexane, dry blend for 2 minutes with a Henschel mixer, and add MA to it.
0.375 parts by weight of H was added, dry blending was further performed for 2 minutes with a Henschel mixer, and the mixture was melt-kneaded at a resin temperature of 255 ° C. and pelletized. The graft MAH content of this product was 0.30% by weight by infrared spectroscopy.

Modified PE (d) Density 0.900 g / cm ³ , MFR = 4.0 g / 10 c
m ³ , melting point = 98 ° C., branch number 72 / 1000C LL
To DPE (d), 0.01 was added 2,5-dimethyl-2,5-t-butylperoxyhexane as a radical initiator.
Add 2 parts by weight and dry blend for 2 minutes with a Henschel mixer, then add 0.375 parts by weight of MAH and add 2 more parts.
Dry blend with a Henschel mixer for 232 minutes
The mixture was melt-kneaded and pelletized at a resin temperature of ° C. The grafted MAH content of this product was 0.2 by infrared spectroscopy.
It was 6% by weight.

The characteristics of the unmodified linear ultra-low density PE (hereinafter abbreviated as L-ULDPE) used in the same manner are as follows. L-ULDPE (a) Density produced by slurry polymerization method 0.904 g / cm ³ , M
FR = 1.0 g / 10 minutes, melting point = 120 ° C., branch number 28 / 1000C.

L-ULDPE (b) Density produced by slurry polymerization method 0.897 g / cm ³ , M
FR = 0.7 g / 10 minutes, melting point = 115 ° C., branch number 47 / 1000C.

L-ULDPE (c) Density produced by slurry polymerization method 0.907 g / cm ³ , M
FR = 6.5 g / 10 minutes, melting point = 121 ° C., branch number 21 / 1000C.

Production of Adhesive Material Unmodified HDPE (a) and (b) above, unmodified L
LDPE (c) and (d) and modified L-ULDPE
(A), (b), (c) and (d) were mixed in the proportions shown in Table 1 and Table 2 and mixed with a single screw extruder having a diameter of 50 mm to 20
Melt-kneading was performed at a temperature of 0 to 220 ° C. to prepare adhesives (I) to (XVI) shown in Tables 1 and 2.

The density (ρ) of the obtained adhesive material is determined by JIS-K.
7112 method and acoustic impedance (Z)
Is an ultrasonic thickness gauge manufactured by Japan Panametrics Co., Ltd. equipped with a vertical probe using a piezo element as a diaphragm.
The sound velocity c when an ultrasonic wave having a frequency of 20 MHz is incident on the press plate (30 mm × 30 mm) of m in the thickness direction,
It was calculated by the following formula. Z = ρ × c [g / cm ² · μsec]

[0073]

[Table 1]

[0074]

[Table 2]

Examples 1 to 12 and Comparative Examples 1 to 9 As shown in Tables 3 and 4, the above-mentioned adhesives were used as the adhesives.
(I) to (XVI), HLMFR = 4.8g as main material
/ 10 minutes, density = 0.945 g / cm³， Sound Impeder
(Zo) = 2.23 × 10^-1g / cm²・ Μsec
HDPE (a) or MFR = 0.3 g / 10 min, density = 0.
948, Zo = 2.26 × 10^-1g / cm ²・ Μsec
Using HDPE (b), and as EVOH,
Ren content 29 mol%, melting point by DSC method 189 ° C., 2
MFR at 30 ° C = 4g / 10min, density 1.20g /
cm³Multi-layer sheet molding of 3 types and 5 layers using EVOH
(Molding temperature 210 ℃, thickness composition, each main material layer 1.5mm, each
Adhesive layer 0.10mm, EVOH layer 0.08mm)
A three-kind five-layer multi-layer laminated structure (sheet) was prepared.

Width 10 mm, length 15 from the flat portion of the container
A 0 mm multi-layered piece was prepared, and the initial adhesive strength P ₀ between the adhesive layer and the EVOH layer was measured by a T-type peeling method using a tension type tensile tester at a peeling speed of 50 mm / min. And shown in Table 4.

Further, the same multi-layered piece was allowed to stand in a 115 ° C. oven for 96 hours, then immersed in a mixed solution of 90% by volume of commercially available regular gasoline and 10% by volume of methanol at 40 ° C. for 1000 hours, and then at 23 ° C., 50 After conditioning 50 hours or more in an atmosphere of RH%, determine the bond strength P ₁ under the same conditions, by comparison with the previous P ₀ as the evaluation of long-term heat fuel resistance, adhesive strength retention rate (P ₀ To 100
The value of P ₁ ) was calculated and the evaluations are shown in Tables 3 and 4.

Further, the detectability of the adhesive is judged by the following method. That is, using the apparatus used for measuring the acoustic impedance, ultrasonic waves (frequency 20 MHz) are incident on each multilayer laminated structure material, and waveform observation is performed by installing a polaroid camera for recording pulse waves reflected at respective interfaces. A pulse waveform was recorded with the camera. The model of this record is shown in FIG. Figure 1 is 3 kinds 5
The pulse waveform which the ultrasonic wave injects from one main material layer side of the multilayer laminated structure (sheet) of a layer, and the reflection pulse in each interface was output with the oscilloscope for observation is shown. More specifically, the vertical axis represents the intensity of the reflected wave and the horizontal axis represents the distance in the thickness direction from one surface of the multilayer laminated structure. The pulse input from the left side of FIG. 1 shows a reflected wave intensity peak indicated by “a” on the surface of the main material layer, and then a part of the pulse enters the wall of the laminated constituent material, and a peak “a” and a peak “a”. The light passes through the thickness of the main material layer corresponding to the distance between "b" and "b" and reflects at the surface of the adhesive layer (interface with the main material layer). In the case of this example (Fig.), The peaks "a" and "b" indicate opposite directions because the value of the adhesive layer (Z ₁ ) is lower than the acoustic impedance (Z ₀ ) of the main material layer. (Z ₀ > Z ₁ ). Of course, if Z ₁ > Z ₀ , peaks in the same direction are shown. Then, a further part of the pulse shows a peak “C” at the interface between the adhesive layer and the EVOH layer after passing through the thickness of the adhesive layer (the distance between the peak “B” and the peak “C”). Reflect. After passing through the EVOH layer (the distance between the peak “C” and the peak “D”), the reflection is the peak “D”. When this measurement method is used, the difference between the reflected wave intensity peak of the main material layer and the reflected wave intensity peak of the adhesive layer is h ₁ , and the peak of the main material layer and E
The difference from the peak of the VOH layer is h _2, and h ₁ / h ₂ is 0.0
If it is less than 8, it is considered as “no detection” and h ₁ / h ₂ is 0.09.
When it was 5 or more, it was determined to be “detectable”. The reason is h
_{When 1} / h ₂ is less than 0.095, it is extremely difficult to distinguish (identify) the disturbance of the waveform due to noise from the peak of the interface between the main material layer and the adhesive layer.

The symbols shown after the numerical values of h ₁ / h ₂ in Tables 3 and 4 are the detectability evaluated by the following criteria. ◎ Very good detectability ○ Good detectability △ Detectable × Difficult to detect

[0080]

[Table 3]

[0081]

[Table 4]

[0082]

INDUSTRIAL APPLICABILITY The multilayer laminated structure material of the present invention is excellent in barrier properties, and is extremely suitable for quality control or process control because the nondestructive detection of the adhesive layer can be easily performed by the ultrasonic reflection method. Have characteristics. Therefore, the multi-layer laminated structure material of the present invention can be widely used for multi-layer packaging containers, industrial materials, automobile parts, parts materials for electronic / electrical devices, and the like.

[Brief description of drawings]

FIG. 1 shows a pulse waveform obtained by injecting an ultrasonic wave from one main material layer side of a multilayer laminated structure of 5 layers of 3 types and outputting a reflection pulse at each interface of three layers on an incident side with a waveform observation oscilloscope. Show.

[Explanation of symbols]

 A: Main material layer (incident side) surface peak b: Main material layer-adhesive layer interface peak c: Adhesive layer-EVOH layer interface peak d: EVOH layer-adhesive layer (incident side) peak

Claims (1)

(57) [Claims] 1. A layer structure in which a main material layer containing a polyethylene resin as a main component is laminated on the outside and a saponified layer of an ethylene-vinyl acetate copolymer is laminated on the inside through at least an adhesive layer. A multi-layer laminated structure material, wherein the adhesive layer has (A) a density of 0.930 g / cm ³ or more and a main chain carbon number of 1
High-density polyethylene resin with 20 or less short chain branches per 000 and a melt flow rate of 0.01 g / 10 minutes or more, density of 0.910 g / cm ³ or more and 0.935 g
/ Cm ^{3 or} less, melt flow rate 0.1 to 50 g / 1
0 minutes, melting point by differential scanning calorimeter 115-130 ℃,
The number of short chain branches per 1000 carbon atoms in the main chain is 5 to 30
Individual linear low-density polyethylene resin, modified high-density polyethylene resin obtained by grafting unsaturated carboxylic acid and / or its derivative on the high-density polyethylene resin, and unsaturated carboxylic acid on the linear low-density polyethylene resin And / or a resin selected from the group consisting of a modified linear low-density polyethylene resin obtained by grafting a derivative thereof, wherein the modified high-density polyethylene resin and / or the modified linear low-density polyethylene resin is 0.1% by weight. % Of polyethylene resin containing 60% to 95% by weight and (B) density of 0.890 g / cm ³ or more and 0.910 g / cm ³ or more.
Less than ^3, 18 to 60 short chain branches per 1000 main chain carbon atoms, melt flow rate 0.1 to 30 g / 1
0 minutes, melting point by differential scanning calorimetry 110-125 ℃
Which contains 40 to 5% by weight of a linear ultra low density polyethylene resin having a density of 0.925 g / cm ³ or more, and a proportion of a grafted unsaturated carboxylic acid and / or a derivative thereof.
A resin composition of 0.001 to 5.0% by weight, 20
The difference in acoustic impedance between the main material layer and the adhesive material layer measured using ultrasonic waves of up to 25 MHz is 8.5 × 10 ⁻³ g / cm 2.
A multi-layer laminated structure material having a length of ² μsec or more.