JP7206747B2 - Adhesive resin composition and easily peelable film - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive resin composition containing an ethylene-vinyl acetate copolymer, and more particularly to an adhesive resin composition that exhibits excellent adhesion to paper, excellent adhesive strength stability under high-temperature and high-humidity environments, and The present invention relates to an adhesive resin composition free from paper fluff and an easily peelable film using the resin composition.

Conventionally, plastic containers made of polyethylene, polypropylene, polystyrene, etc. and paper containers mainly made of paper have been used for food packaging and packaging of industrial parts. In addition, an easily peelable film having a smooth peeling performance is used at the time of peeling.

Among them, the lid material of paper food containers and the cover tape of the carrier tape for transporting electronic parts (hereinafter referred to as "paper carrier") have heat seal strength and easy peelability, and the paper of the container peels off and fluffs when peeled. , so-called paper peeling does not occur. In addition, in recent years, with the speeding up of content filling, it is necessary to obtain sufficient adhesive strength in a short sealing time.

Furthermore, in the electronic component transport process, when peeling off the cover tape that is the cover material, the occurrence of peeling vibration due to hunting of the peeling strength and paper peeling causes the electronic components and IC chips in the paper carrier to pop out. However, the problem is that there is a problem in taking out the .

Especially in recent years, factories that use electronic components have moved to hot and humid regions such as Southeast Asia, and they are exposed to hot and humid environments during transportation and storage. There is an increasing number of problems in picking out parts due to such factors as

For this reason, requirements for cover tape sealing materials are increasing, such as that the variation in peel strength is small (peel strength stability), and that the adhesive strength does not change significantly even after long-term storage under high temperature and high humidity (adhesion strength maintenance). is coming.

Examples of sealing materials for cover tapes include polyethylene, a mixture obtained by adding a tackifier to an ethylene-vinyl acetate copolymer (see, for example, Patent Document 1), an ethylene-vinyl acetate copolymer and a low-molecular-weight ethylene as a tackifier. - A mixture containing a vinyl acetate copolymer (see, for example, Patent Document 2), an ethylene-acrylic acid copolymer modified with maleic anhydride, and a polystyrene resin or an acrylic acid ester copolymer added to a tackifier. A mixture (see, for example, Patent Document 3) and the like are used.

However, these have not been able to satisfy all of the low-temperature sealability, excellent peeling appearance (less paper peeling), peel strength stability, and adhesion strength maintenance under high temperature and high humidity conditions.

Japanese Patent Publication No. 03-037760 JP 2009-035645 A WO2018-061442

The present invention has excellent low-temperature sealability, small fluctuations in peel strength during peeling, small change in adhesive strength even after storage in a high-temperature and high-humidity environment, and less peeling of paper containers during peeling. An object of the present invention is to provide a flexible resin composition and an easily peelable film using the resin composition.

The present inventors have made intensive studies to solve the above problems, and found that a resin composition with a specific formulation has excellent low-temperature sealing properties, has a small fluctuation in peel strength during peeling, and can be stored in a high-temperature and high-humidity environment. The inventors have found that the change in adhesive strength is small even after the application, and that the paper-made container is less likely to peel off when peeled off, leading to the completion of the present invention.

An embodiment of the adhesive resin composition according to the present invention has the following characteristics. i.e.
Ethylene-vinyl acetate having a vinyl acetate content of 3% by weight or more and 15% by weight or less as measured by JIS K6924-1 and a melt mass flow rate of 1 g/10 minutes or more and 40 g/10 minutes or less as measured by JIS K6924-1. 50 to 90 parts by weight of the copolymer (A), a crystalline or amorphous resin having a glass transition temperature of 60 to 120°C, or a block having a glass transition temperature of 60 to 120°C 3 parts by weight or more and 30 parts by weight or less of at least one resin (B) of a copolymer containing a segment in its molecular structure, and 5 parts by weight or more and 20 parts by weight or less of a tackifier (C) (where ( A), (B) and (C) total 100 parts by weight).

The present invention also relates to an easily peelable film comprising an adhesive layer and a supporting substrate layer made of the adhesive resin composition, and a paper container lid comprising the easily peelable film. It is.

The present invention will be described in detail below.

The adhesive resin composition of the present invention has a vinyl acetate content of 3 wt % or more and 15 wt % or less as measured by JIS K6924-1, and a melt mass flow rate of 1 g/10 min or more and 40 g as measured by JIS K6924-1. 50 parts by weight or more and 90 parts by weight or less of an ethylene-vinyl acetate copolymer (A) which is /10 minutes or less, a crystalline or amorphous resin whose glass transition temperature is 60° C. or more and 120° C. or less, or 60° C. or more 3 parts by weight or more and 30 parts by weight or less of at least one resin (B) of a copolymer containing a block segment having a glass transition temperature of 120° C. or less in its molecular structure, and 5 parts by weight of a tackifier (C) part or more and 20 parts by weight or less (where the total of (A), (B) and (C) is 100 parts by weight).

Examples of the ethylene-vinyl acetate copolymer (A) constituting the adhesive resin composition of the present invention include ethylene-vinyl acetate copolymers (EVA) obtained by known production methods. Since it is excellent in low-temperature sealability, adhesive strength maintenance in high-temperature and high-humidity environments, and prevention of paper peeling, the vinyl acetate content measured in accordance with JIS K6924-1 is 3% by weight or more and 15% by weight. or less, preferably 5% by weight or more and 10% by weight or less. Here, when the vinyl acetate content is 3% by weight or more, the resulting adhesive resin composition has more excellent low-temperature sealability. Further, when the vinyl acetate content is 15% by weight or less, the obtained adhesive resin composition has moderate adhesive strength in a high-temperature and high-humidity environment and good paper peeling property.

In addition, the melt mass flow rate of the ethylene-vinyl acetate copolymer (A) measured according to JIS K6924-1 makes it an adhesive for sealants with excellent extrusion lamination processability, low-temperature sealability, and paper peeling prevention. Therefore, it is in the range of 1.0 g/10 min or more and 40 g/10 min or less, preferably 3.0 g/10 min or more and 30 g/10 min or less. When the melt mass flow rate is 1.0 g/10 minutes or more, drawdown properties and low-temperature sealing properties during extrusion lamination processing are further improved. When the melt mass flow rate is 40 g/10 minutes or less, the melt film becomes stable during extrusion lamination and becomes difficult to stick to the cooling roll.

The blending ratio of the ethylene-vinyl acetate copolymer (A) constituting the present invention is 50 parts by weight or more and 90 parts by weight or less, preferably 50 parts by weight or more and 85 parts by weight or less. This makes the composition of the present invention more excellent in low-temperature sealability, peel strength stability, and extrusion lamination processability. When the blending ratio of the ethylene-vinyl acetate copolymer (A) is 50 parts by weight or more, the obtained adhesive resin composition has excellent extrusion lamination workability. On the other hand, when the content is 90 parts by weight or less, the low-temperature sealability of the obtained adhesive resin composition is further improved.

Specific examples of the ethylene-vinyl acetate copolymer (A) include (trade name) Ultrathen (manufactured by Tosoh Corporation).

The ethylene-vinyl acetate copolymer (A) may be used alone or in combination of two or more. Even when two or more types are used in combination, the total mixing ratio of the ethylene-vinyl acetate copolymer in the adhesive resin composition is 50 parts by weight or more and 90 parts by weight or less.

The resin (B) constituting the adhesive resin composition of the present invention is a crystalline or amorphous resin having a glass transition temperature of 60° C. or higher and 120° C. or lower, or a glass transition temperature of 60° C. or higher and 120° C. or lower. It is at least one resin of a copolymer containing a block segment in its molecular structure. Here, the glass transition temperature of the segment of the resin or copolymer is in the range of 60°C or higher and 120°C or lower, more preferably in the range of 60°C or higher and 90°C or lower.

In other words, (B) in the present invention is either a resin itself having a predetermined glass transition temperature or a copolymer containing block segments having a predetermined glass transition temperature in its molecular structure.

When the glass transition temperature is 60° C. or higher, the adhesion strength in a high-temperature and high-humidity environment becomes moderate, and the paper peelability when peeled off becomes good. On the other hand, when the glass transition temperature is 120° C. or lower, the low-temperature sealability becomes more excellent.

The crystalline or amorphous resin (B) having a glass transition temperature in the range of 60° C. or higher and 120° C. or lower includes polymethyl (meth)acrylate, polystyrene, polyethylene terephthalate, polyvinyl alcohol or polyvinyl chloride. At least one type can be mentioned.

The resin (B) constituting the present invention may be a copolymer containing a block segment having a glass transition temperature of 60° C. or higher and 120° C. or lower in its molecular structure, and the copolymer is crystalline or amorphous. It may be at least one.

Moreover, the resin (B) may contain a carboxylic acid group, a maleic anhydride group, an epoxy group, or the like in its molecular structure in order to enhance adhesion to the carrier tape.

The copolymer (B) containing in its molecular structure a block segment having a glass transition temperature in the range of 60° C. or higher and 120° C. or lower is preferably a styrene-butadiene-styrene block copolymer, a styrene-ethylene-butadiene-styrene block copolymer. It is at least one selected from the group consisting of polymers, methyl methacrylate-normal-butyl acrylate-methyl methacrylate block copolymers, and acrylic-epoxy copolymers.

That is, the resin (B) is polymethyl (meth)acrylate, polystyrene, polyethylene terephthalate, polyvinyl alcohol, polyvinyl chloride, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene block copolymer, It is preferably at least one selected from the group consisting of methyl methacrylate-normal-butyl acrylate-methyl methacrylate block copolymer or acrylic-epoxy copolymer, more preferably polyethylene terephthalate, styrene-butadiene-styrene block copolymer. It is at least one selected from the group consisting of polymers or acrylic-epoxy copolymers. Thereby, the adhesive strength of the adhesive composition of the present invention is further improved.

The blending ratio of the resin (B) constituting the present invention is 3 parts by weight or more and 30 parts by weight or less, more preferably 4 parts by weight or more and 20 parts by weight or less, further preferably 5 parts by weight or more because of excellent extrusion lamination processability. 15 parts by weight or less. Here, when the content is 3 parts by weight or more, the resulting adhesive resin composition has more excellent adhesive strength maintenance properties under high-temperature and high-humidity environments. On the other hand, when the content is 30 parts by weight or less, the resulting adhesive resin composition is less prone to melt film cracking and has more excellent extrusion lamination processability.

The tackifier (C) constituting the adhesive resin composition of the present invention is, for example, a petroleum resin-based, coumarone resin-based, styrene-based, etc. synthetic petroleum resin-based tackifier, or a natural resin-based tackifier. Examples include rosin-based resins, methyl ester-based resins, glycerin ester-based resins, pentaerythritol-based resins, terpene-based resins, and modified products thereof. Among these tackifiers, synthetic petroleum resin tackifiers include aliphatic petroleum resins, aliphatic hydrogenated petroleum resins, aromatic petroleum resins, aromatic hydrogenated petroleum resins, and alicyclic petroleum resins. There are resins, alicyclic hydrogenated petroleum resins, copolymer hydrogenated petroleum resins, and the like. Among these, alicyclic petroleum resins and alicyclic hydrogenated petroleum resins are preferable, and more preferably alicyclic Hydrogenated petroleum resin.

The tackifier (C) preferably has a softening point of 100° C. or higher and 140° C. or lower, more preferably 110° C. or higher and 140° C. or lower, still more preferably 120° C. or higher and 135° C. or lower, as measured by the ring and ball method. is. When the softening point is 100° C. or higher, the obtained adhesive resin composition is more excellent in maintaining adhesive strength in a high-temperature and high-humidity environment. Moreover, when the softening point is 140° C. or lower, the resulting adhesive resin composition is superior in extrusion lamination workability.

Examples of commercially available products of the tackifier (C) that can be used in the present invention include (trade name) Alcon (manufactured by Arakawa Chemical Industries, Ltd.) and Imarv (manufactured by Idemitsu Kosan Co., Ltd.).

The blending ratio of the tackifier (C) constituting the present invention is 5 parts by weight or more and 20 parts by weight or less, more preferably 7 parts by weight or more and 15 parts by weight or less, still more preferably 9 parts by weight or more and 11 parts by weight or less. be. Here, when the content is 5 parts by weight or more, the resulting adhesive resin composition is more excellent in low-temperature sealing properties. Further, when the content is 20 parts by weight or less, the obtained adhesive resin composition has less paper peeling.

In the adhesive resin composition of the present invention, it is preferable to replace 5 parts by weight or more and 20 parts by weight or less of the ethylene-vinyl acetate copolymer (A) with the ethylene resin (D) in order to improve the peeling properties. Here, the ethylene-based resin (D) is an ethylene homopolymer, an ethylene/α-olefin copolymer, or a composition thereof, and the molecular chain may be linear or branched. good too.

Such ethylene-based resin (D) is not particularly limited, and examples thereof include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and low-molecular-weight waxes thereof. In particular, at least one of low-density polyethylene and low-molecular-weight wax of low-density polyethylene is preferable because of its excellent extrusion lamination processability.

High-density polyethylene can be obtained by a conventionally known medium-pressure ion polymerization method or low-pressure ion polymerization method.

Low-density polyethylene can be obtained by a conventionally known high-pressure radical polymerization method.

Linear low-density polyethylene can be obtained by high-, medium-, or low-pressure ion polymerization using Ziegler-Natta catalysts, Phillips catalysts, or metallocene catalysts.

α-olefins used in linear low-density polyethylene include propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, 1- At least one selected from the group consisting of octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene can be used.

The number average molecular weight (Mn) of the ethylene-based resin (D) is preferably in the range of 1,000 to 13,000, more preferably in the range of 1,500 to 12,000. Here, when the number average molecular weight is 1,000 or more, the obtained adhesive resin composition is excellent in adhesive strength maintenance property in a high-temperature and high-humidity environment, which is preferable. Further, when the number average molecular weight is 13,000 or less, the obtained adhesive resin composition has a small fluctuation range of peel strength and less paper peeling, which is preferable.

Methods for measuring the number average molecular weight include GPC method, NMR method, vapor pressure osmosis method and the like.

Specific examples of the ethylene-based resin (D) include (trade name) Petrothene (manufactured by Tosoh Corporation), Sanwax (manufactured by Sanyo Chemical Industries, Ltd.), Hi-Wax (manufactured by Mitsui Chemicals, Inc.), and the like. be able to.

The blending ratio of the ethylene resin (D) constituting the present invention is preferably 5 parts by weight or more and 20 parts by weight or less, more preferably 5 parts by weight or more and 15 parts by weight or less, still more preferably 5 parts by weight or more and 10 parts by weight. It is below the department. Here, when it is 5 parts by weight or more, the obtained adhesive resin composition has excellent peel strength stability (the fluctuation range of peel strength is small), while when it is 20 parts by weight or less, the obtained adhesive resin composition is excellent in low-temperature sealing properties.

The ethylene-based resin (D) replaces a part of the ethylene-vinyl acetate copolymer (A) with the ethylene-based resin (D), and the ethylene-vinyl acetate copolymer (A) and the ethylene-based resin (D ) is preferably 50 to 90 parts by weight, more preferably 50 to 85 parts by weight.

The adhesive resin composition of the present invention preferably has a melt mass flow rate of 5.0 g/10 min or more and 100 g/10 min or less, as measured by JIS K6924-1, because it is particularly excellent in extrusion lamination processability. , more preferably 5.0 g/10 minutes or more and 50 g/10 minutes or less.

When kneading the adhesive resin composition of the present invention, various compounding materials are simultaneously pre-blended using a mixer such as a Henschel mixer or a tumbler, and then melted using a single-screw extruder, twin-screw extruder, kneader, Banbury, or the like. A method of kneading may be mentioned.

In addition, the adhesive resin composition of the present invention may contain other thermoplastic resins, rubbers, antistatic agents, light stabilizers, ultraviolet absorbers, nucleating agents, lubricants, oxidation At least one selected from the group consisting of inhibitors, antiblocking agents, fluidity improvers, release agents, flame retardants, colorants, inorganic neutralizers, hydrochloric acid absorbers, and filler conductive agents may be included.

The adhesive resin composition of the present invention is used as a sealant adhesive layer of an easily peelable film used as a lid material for paper containers.

The easily peelable film of the present invention includes an adhesive layer (hereinafter sometimes referred to as a "sealant adhesive layer") made of the above adhesive resin composition and a supporting substrate layer. The supporting substrate constituting the supporting substrate layer may be any one having self-supporting properties, and examples thereof include polyethylene, polypropylene, olefin resins such as ethylene-acid copolymer resins, polyethylene terephthalate, polybutylene terephthalate, and polyethylene. Polyester resins such as naphthalate, plastic films composed of thermoplastic resins such as polyamide resins, paper such as Japanese paper and composite paper, metal foils composed of metals such as aluminum, single or laminates of these, etc. mentioned. The thickness of the supporting substrate layer can be selected depending on the application within a range that does not impair the mechanical strength, workability, etc., but is generally 5 μm or more and 100 μm or less, preferably 10 μm or more and 50 μm or less.

The thickness of the sealant adhesive layer can be selected depending on the application within a range that does not impair the adhesiveness, workability, etc., but is generally 5 μm to 50 μm, preferably 10 μm to 30 μm.

In the easily peelable film of the present invention, an intermediate layer may be provided between the supporting substrate layer and the sealant adhesive layer in order to enhance the adhesion between the two layers. This intermediate layer can be composed of a thermoplastic resin such as a polyolefin resin, a thermoplastic elastomer, or the like, and these components can be used alone or in combination of two or more. For example, polyolefin resins include polyethylene, ethylene copolymers (polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, etc.) and modified products thereof. are mentioned. The intermediate layer contains various additives such as at least one selected from the group consisting of antioxidants, lubricants, antistatic agents, conductive agents, antiblocking agents, and tackifiers, as long as the effects of the present invention are not impaired. It's okay to be

The thickness of the intermediate layer can be selected depending on the application within a range that does not impair workability, but is generally 5 μm or more and 30 μm or less.

In the easily peelable film of the present invention, an anchor coat layer is provided between the supporting substrate layer and the sealant adhesive layer or between the supporting substrate layer and the intermediate layer in order to increase adhesion between the two layers. can also

The easily peelable film of the present invention is used for containers mainly made of paper, such as containers made of crepe paper, Japanese paper, synthetic paper, composite paper, etc., and pulp molded containers made of reeds, sugar cane, etc. It is suitable as a lid material for a container.

The easily peelable film of the present invention is mainly made of paper for transporting electronic parts, for example, multi-layered paperboard mainly made of wood pulp such as hardwood pulp and softwood pulp, and those on the surface It is suitable as a cover material (cover tape) for a paper container (carrier tape) for transporting electric parts, which is made of multi-layered paperboard coated with starch or polyvinyl alcohol as a surface sizing agent.

When used as a lid material for transporting electrical parts, polyethylene terephthalate resin is preferable for the supporting substrate layer because of its excellent heat resistance. is preferred.

Among paper containers, especially carrier tapes for transporting electronic components, an antistatic agent is added or applied to the sealant adhesive layer of the cover tape serving as a lid material for the purpose of suppressing electrostatic adhesion of electronic components.

The method of adding the antistatic agent to the sealant adhesive layer is not particularly limited, but a method of adding it when melt-kneading the adhesive resin composition that will be the sealant adhesive layer, or a method of sprinkling the pellets after melt-kneading. By laminating a resin to which an antistatic agent is added, a sealant adhesive layer having antistatic performance can be obtained.

The method of applying the antistatic agent to the sealant adhesive layer is not particularly limited, but there is a method of uniformly applying a solution containing the antistatic agent to the surface of the sealant adhesive layer by spraying or using a roll coater, followed by drying.

Any antistatic agent may be used as long as it prevents the easily peelable film from being charged, such as glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, polyethylene glycol rough acid Nonionic surfactants such as esters, polyoxyethylene sorbitan fatty acid esters and fatty acid alkanolamides, polyglycerin fatty acid esters, polyoxyalkylene alkyl ethers and the like can be mentioned.

The method for producing the easily peelable film of the present invention is not particularly limited, but a method of extrusion laminating a sealant adhesive onto a supporting substrate film, a method of molding a multilayer film containing at least one layer of a sealant adhesive in advance, and a supporting film. At least one method of the group consisting of methods of lamination with a substrate film can be mentioned. For example, (1) an extrusion lamination method in which an anchor coating agent is applied to a supporting substrate film and an adhesive layer is melt extruded, (2) an anchor coating agent is applied to a supporting substrate film, and an intermediate layer is melt extruded. , an extrusion lamination method in which an adhesive layer is melt-extruded thereon; (4) A co-extrusion lamination method in which an anchor coating agent is applied to a supporting base film and the intermediate layer and the adhesive layer are melt-extruded at the same time; A method of molding a multilayer film containing at least one layer of adhesive and bonding it to a supporting substrate film coated with an anchor coating agent. (6) An extrusion lamination method of laminating a supporting substrate film coated with an anchor coating agent and a multilayer film containing at least one layer of a sealant adhesive by melt extruding an intermediate layer using extrusion lamination.

The adhesive resin composition of the present invention is used as a resin for a sealant layer of a lid material for paper containers, and the obtained laminate is used as a lid material for paper packaging containers for foods, electronic parts, etc. It is preferably used as a cover material (cover tape) for a paper container (carrier tape) for transporting parts.

The adhesive resin composition of the present invention is an adhesive for bonding lid materials suitable for paper containers, has excellent low-temperature sealing properties, has a small fluctuation in peel strength during peeling, and can be stored in a high-temperature and high-humidity environment. It is useful as an adhesive for a container lid material sealant and an easily peelable film, with little change in adhesive strength after peeling, and little peeling of the paper container when peeled.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these.
(1) Melt mass flow rate (MFR)
The MFR of the ethylene-vinyl acetate copolymer and the ethylene-vinyl alcohol copolymer were measured according to JIS K6924-1.
(2) number average molecular weight (Mn)
The number average molecular weight of the ethylene resin was measured by the GPC method. In the GPC method, HLC-8121GPC/HT manufactured by Tosoh Corporation is used as a measuring device, and three TSKgelGMHHR-H(20)HT (manufactured by Tosoh Corporation, inner diameter 7.8 mm, length 30 cm) are connected as a separation column. and used. For the moving bed, HPLC grade 1,2,4-trichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) added with 0.05% of BHT (manufactured by Wako Pure Chemical Industries, Ltd.) as an antioxidant is used. and moved at a flow rate of 1.0 mL/min through a separation column maintained at 140°C. 0.3 mL of a sample solution whose concentration was adjusted to 1.0 mg/mL was injected into this, and separated sample components were detected with a differential refractometer. The number average molecular weight (Mn) was calculated using a fifth-order approximation curve prepared using standard polystyrene (manufactured by Tosoh Corporation) as a calibration curve.
(3) Glass transition temperature The glass transition temperature was measured according to JISK7121.
(4) Vinyl Acetate Content The vinyl acetate content was measured according to JISK6924-1.
(5) Adhesive strength Taping tester (VS-120 manufactured by Vanguard Systems Co., Ltd.) by superimposing the adhesive surface of the easily peelable film and the paper base material that will be the carrier tape, U-shaped seal bar (0.5 mm Width x 2 molds, seal bar length 8.2 mm) were used to perform pressurized heat bonding under the conditions of 160°C, 0.1 MPa, and 0.1 seconds. After standing to cool, the adhesive strength was measured under the conditions of 180° peeling and peeling speed of 300 mm/min, and the average value was obtained. An adhesion strength of 0.20 N/mm or more was regarded as good low-temperature sealability.
(6) Adhesive strength stability (fluctuation width) at the time of peeling
The adhesive surface of the easily peelable film and the paper substrate that will be the carrier tape are superimposed, and the taping tester (Vanguard Systems Co., Ltd. VS-120 model), U-shaped seal bar (0.5 mm width x 2 types) , seal bar length 8.2 mm), the heat sealing conditions are set to 0.1 MPa and 0.1 seconds, and the heat seal setting temperature is changed so that the heat seal strength is about 0.25 N / mm. Glued. After cooling, the adhesive strength was measured under the conditions of 180 degree peeling and peeling speed of 300 mm / min, and the difference between the maximum and minimum values of the measured values was calculated as the adhesive strength stability. ), 0.15 N/mm or less was considered good.
(7) Change in Adhesive Strength after Storage in a High-Temperature and Humidity Environment Under the same conditions as in (6) above, the easily peelable film and the carrier tape were pressure-heated and adhered. The bonded sample was stored in an oven at 60° C. under normal pressure and 60° C. and 95% RH (humidity) for 10 days. The adhesive strength was measured under the conditions of minutes, and the average value was obtained. As the maintainability of the peel strength, a value obtained by subtracting the average peel strength after 10 days (after storage in the oven) from the average initial strength (before storage in the oven) was used (amount of change over time). A change over time in the range of 0 to less than 0.1 N/mm was evaluated as good.
(8) Peeling Appearance Under the same conditions as in (6) above, the easily peelable film and the carrier tape were pressure-heated and adhered. The bonded sample is stored in an oven at 60° C. and 95% RH (humidity) for 10 days, and after 10 days, the sample is taken out and allowed to cool. The peeling was performed under the conditions of an angle of 60 degrees and a peeling speed of 300 mm/min. The adhesive resin composition layer surface of the peeled easily peelable film was visually checked to evaluate the peeling state. The samples were evaluated as ◯>Δ>X from those with less paper peeling, and ◯ was regarded as good.

Example 1
As the ethylene-vinyl acetate copolymer (A), resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. Polymethyl (meth)acrylate (B1) having a glass transition temperature of 110° C. and a melt mass flow rate of 0.2 g/10 min as the resin (B) (manufactured by Kuraray Co., Ltd., trade name Parapet G-1000) ) 10 parts by weight, and 10 parts by weight of hydrogenated petroleum resin (C1) (manufactured by Arakawa Chemical Co., Ltd., product name Alcon P125; softening temperature 125 ° C.) as tackifier resin (C) were pre-blended in a tumbler mixer. The mixture was melt-kneaded at 200° C. using a twin-screw extruder to obtain pellets of the adhesive resin composition.

Pellets of the above adhesive resin composition are supplied to a single-screw extrusion laminator (manufactured by Placo Co., Ltd.) having a screw with a diameter of 25 mm, extruded from the T-die so that the resin temperature directly below the T-die is 220 ° C., and extruded in advance. A laminated substrate consisting of a biaxially stretched polyester film (25 μm thick) prepared by lamination and low density polyethylene (15 μm thick, trade name Petrothene 203 manufactured by Tosoh Corporation) was pulled to the low density polyethylene side. Extrusion lamination molding was carried out at a take-up speed of 20 m/min, an air gap length of 130 mm, and an adhesive resin composition layer having a thickness of 15 μm. An easily peelable film having a layer made of the adhesive resin composition was obtained.

Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 2
Polystyrene (B2) (manufactured by DIC Corporation, trade name Dick Styrene CR-2500 ) was used, and the kneading temperature of the twin-screw extruder was set to 160°C to obtain an adhesive resin composition. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 3
10 parts by weight of amorphous polyethylene terephthalate (B3) (manufactured by Eastman Chemical Co., Ltd., trade name Eastar 5011) having a glass transition temperature of 70° C. and a melt mass flow rate of 3 g/10 min instead of polystyrene (B2) An easily peelable film was obtained in the same manner as in Example 2, except that an adhesive resin composition was obtained using . Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 4
Instead of polystyrene (B2), a styrene-butadiene-styrene block copolymer (SBS) (B4) (B4) ( An easily peelable film was obtained in the same manner as in Example 2, except that 10 parts by weight of Asaflex 830 (trade name, manufactured by Asahi Kasei Corp.) was used to obtain an adhesive resin composition. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 5
Adhesion using 10 parts by weight of acrylic-epoxy copolymer (B5) (manufactured by NOF Corporation, trade name Marproof G-0150M) with a glass transition temperature of 71° C. instead of polystyrene (B2). An easily peelable film was obtained in the same manner as in Example 2, except that a flexible resin composition was obtained. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 6
Resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. 10 parts by weight of a styrene-butadiene-styrene block copolymer (SBS) (B4) (manufactured by Asahi Kasei Corporation, trade name Asaflex 830) having a temperature of 75° C. and a melt mass flow rate of 1 g/10 minutes, tackifier 10 parts by weight of hydrogenated petroleum resin (C1) (manufactured by Arakawa Chemical Co., Ltd.; product name: Alcon P125; softening temperature: 125°C) as agent resin (C); An easily peelable film was prepared in the same manner as in Example 2, except that 6 parts by weight of resin (D1) (manufactured by Sanyo Chemical Co., Ltd., trade name Sanwax 151P) was used to obtain an adhesive resin composition. Obtained. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Example 7
Resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. Epoxy copolymer (B5) (manufactured by NOF Corporation, trade name Marproof G-0150M) 10 parts by weight, hydrogenated petroleum resin (C1) (Arakawa Chemical Co., Ltd.) as tackifier resin (C) Made by Alcon P125; softening temperature 125° C.) 10 parts by weight, resin (D1) having a number average molecular weight (Mn) of 2000 as ethylene-based resin (D) (manufactured by Sanyo Chemical Industries, Ltd., product name Sunwax 151P) An easily peelable film was obtained in the same manner as in Example 2, except that 6 parts by weight was used to obtain an adhesive resin composition. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 1 shows the evaluation results.

Comparative example 1
As the ethylene-vinyl acetate copolymer (A), resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. 10 parts by weight of hydrogenated petroleum resin (C1) (manufactured by Arakawa Chemical Co., Ltd., trade name Alcon P125; softening temperature 125° C.) as tackifier resin (C) to obtain an adhesive resin composition. An easily peelable film was obtained in the same manner as in Example 2 except for the above. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 2 shows the evaluation results. Adhesive strength, adhesive strength stability (fluctuation) at peeling, adhesive strength change after high temperature and constant humidity storage, and peel appearance were poor.

Comparative example 2
As the ethylene-vinyl acetate copolymer (A), resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. Part, 10 parts by weight of hydrogenated petroleum resin (C1) (trade name Alcon P125 manufactured by Arakawa Chemical Co., Ltd.; softening temperature 125 ° C.) as tackifier resin (C), number average molecular weight as ethylene resin (D) In the same manner as in Example 2, except that 6 parts by weight of resin (D1) (manufactured by Sanyo Chemical Industries, Ltd., product name: Sunwax 151P) having a (Mn) of 2000 was used to obtain an adhesive resin composition. An easily peelable film was obtained. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 2 shows the evaluation results. It was inferior in adhesive strength.

Comparative example 3
As the ethylene-vinyl acetate copolymer (A), resin (A1) having a vinyl acetate content of 6% by weight and a melt mass flow rate of 8.5 g/10 min. 15 parts by weight of hydrogenated petroleum resin (C1) (manufactured by Arakawa Chemical Co., Ltd., trade name Alcon P125; softening temperature 125° C.) as tackifier resin (C) to obtain an adhesive resin composition. An easily peelable film was obtained in the same manner as in Example 1 except for the above. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 2 shows the evaluation results. It was inferior in adhesive strength stability (fluctuation) at the time of peeling, adhesive strength change after high temperature and constant humidity storage, and peel appearance.

Comparative example 4
As the ethylene-vinyl acetate copolymer (A), 84 parts by weight of a resin (A2) having a vinyl acetate content of 10% by weight and a melt mass flow rate of 9 g/10 min. 10 parts by weight of hydrogenated petroleum resin (C1) (manufactured by Arakawa Chemical Co., Ltd., trade name Alcon P125; softening temperature 125 ° C.) as tackifier resin (C), and number average molecular weight (Mn) as ethylene resin (D) ) is 2000 (product name: Sanwax 151P, Sanyo Chemical Industries, Ltd.) was used to obtain an adhesive resin composition by using 6 parts by weight. A sexual film was obtained. Using the obtained easily peelable film, the measurement was performed by the evaluation method described above. Table 2 shows the evaluation results. After storage at high temperature and constant humidity, the change in adhesive strength and appearance of peeling were poor.

The adhesive resin composition of the present invention is used as a resin for a sealant layer of a lid material for paper containers, and the obtained laminate is used as a lid material for paper packaging containers for foods, electronic parts, etc. It is preferably used as a cover material (cover tape) of a carrier tape for transporting parts.

Claims (7)

Ethylene-vinyl acetate having a vinyl acetate content of 3% by weight or more and 15% by weight or less as measured by JIS K6924-1 and a melt mass flow rate of 1 g/10 minutes or more and 40 g/10 minutes or less as measured by JIS K6924-1. 30 to 85 parts by weight of the copolymer (A), a crystalline or amorphous resin having a glass transition temperature of 60 to 90°C, or a block having a glass transition temperature of 60 to 90°C 3 parts by weight or more and 30 parts by weight or less of at least one resin (B) of a copolymer containing a segment in its molecular structure, 5 parts by weight or more and 20 parts by weight or less of a tackifier (C), and an ethylene resin An adhesive resin comprising 5 parts by weight or more and 20 parts by weight or less of (D) (where the total of (A), (B), (C) and (D) is 100 parts by weight) Composition. Resin (B) is polymethyl (meth)acrylate, polystyrene, polyethylene terephthalate, polyvinyl alcohol, polyvinyl chloride, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene block copolymer, methacrylic acid 2. The adhesive resin composition according to claim 1, wherein the adhesive resin composition is at least one selected from the group consisting of methyl-n-butyl acrylate-methyl methacrylate block copolymer and acrylic-epoxy copolymer. 3. The adhesive resin composition according to claim 1, wherein the ethylene resin (D) has a number average molecular weight (Mn) of 1000 or more and 13000 or less. 4. The adhesive resin composition according to any one of claims 1 to 3, wherein the ethylene-based resin (D) is low-density polyethylene. An easily peelable film comprising an adhesive layer comprising the adhesive resin composition according to any one of claims 1 to 4 and a supporting substrate layer. A lid material for a paper container, comprising the easily peelable film according to claim 5 . 7. The lid material for a paper container according to claim 6 , which is for transporting electronic parts.