JP6841001B2 - Sealant adhesive and lid film - Google Patents

Description

The present invention relates to a film used as a lid material for a container. More specifically, the present invention provides amorphous polyethylene terephthalate (hereinafter referred to as A-PET) having excellent molding processability, high sealing strength and adhesive strength, and excellent heat resistance. It relates to an adhesive for a sealant used for a lid material of a container and a film for a lid material.

Conventionally, plastic containers such as polyethylene, polypropylene, and polystyrene and paper containers mainly made of paper have been used for packaging foods and drinks, pharmaceuticals, industrial parts, etc., and the lid material has protection of the contents. For this purpose, an easily peelable film having stable adhesive strength and easy peeling performance that can be opened with an appropriate strength at the time of peeling is used. Until now, many materials have already been known for containers such as polypropylene and polystyrene, but in recent years, it has been practically excellent for A-PET containers, which are inexpensive and have excellent transparency and cold resistance. No peelable film has been found. When the conventional easily peelable film is used as a lid material for A-PET containers, the adhesive strength is weak, so there is a problem that the lid opens due to vibration or dropping during transportation or storage, and an attempt is made to obtain high adhesive strength. Since the heat seal temperature must be set high, there is a problem that the container is deformed and the sealability is deteriorated. In addition, if it is stored in a low temperature environment after bonding, there is a drawback that the sealing strength is lowered, and there is a problem in practical use. Generally, as an adhesive for a lid material sealant, a mixture consisting of a polyerylene or an ethylene-vinyl acetate copolymer and a tackifier is known, but such a material is sufficient for an A-PET container. Adhesive strength cannot be obtained. Further, a resin composition composed of an ethylene / α-olefin copolymer and an olefin elastomer and / or a styrene elastomer and a tackifier (see, for example, Patent Document 1), an ethylene / α-olefin copolymer and ethylene / polarity. A sealing material consisting of a monomer copolymer, an ABA type block copolymer, and a tackifier (see, for example, Patent Document 2) is used, but all of the molding processability, the sealing strength, and the adhesive strength are all satisfied. I wasn't satisfied.

JP-A-1999-269319 Japanese Patent No. 4438108

However, none of the above methods can sufficiently satisfy the molding processability, the sealing strength with respect to the A-PET container, and the adhesive strength.

An object of the present invention is to provide an adhesive for a sealant and a film for a lid material used for a lid material of an A-PET container, which is excellent in moldability and satisfies the sealing strength and the adhesive strength for an A-PET container. To do.

As a result of diligent studies on the above problems, the present inventors have excellent molding processability in a sealant adhesive containing two specific types of ethylene-vinyl acetate copolymer and a tackifier, and the present invention has an A-PET container. We have found that it is excellent in sealing strength and adhesive strength, and have completed the present invention.
That is, the present invention is an ethylene-vinyl acetate copolymer (A) having a vinyl acetate content of 3 to 15% by weight, and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 8 to 25% by weight. It contains 10 to 50 parts by weight of (B) and 5 to 40 parts by weight of the tackifier resin (C) (the total of (A), (B) and (C) is 100 parts by weight), and has an ethylene-vinyl acetate common weight. The difference between the vinyl acetate content of the coalescence (A) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B) is 3 to 20% by weight, and the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) is ethylene-acetic acid. It relates to an adhesive for a lid material sealant of a container and a film for a lid material, which are smaller than the vinyl acetate content of the vinyl copolymer (B).

The present invention will be described in detail below.

The adhesive for the lid material sealant of the container of the present invention has an ethylene-vinyl acetate copolymer (A) having a vinyl acetate content of 3 to 15% by weight, 10 to 50 parts by weight, and a vinyl acetate content of 8 to 25% by weight. Includes 10 to 50 parts by weight of ethylene-vinyl acetate copolymer (B) and 5 to 40 parts by weight of tackifier resin (C) (total of (A), (B) and (C) is 100 parts by weight). , The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B) is 3 to 20% by weight, that of the ethylene-vinyl acetate copolymer (A). The vinyl acetate content is smaller than the vinyl acetate content of the ethylene-vinyl acetate copolymer (B).

The ethylene-vinyl acetate copolymer (A) has a vinyl acetate content of 3 to 15% by weight, preferably 5 to 10% by weight. When the vinyl acetate content is less than 3% by weight, the obtained sealant adhesive is inferior in low-temperature heat-sealing property, which is not preferable. On the other hand, when the vinyl acetate content exceeds 15% by weight, the obtained sealant adhesive is not preferable because it is inferior in molding processability. The vinyl acetate content in the ethylene-vinyl acetate copolymer can be measured by a method measured in accordance with JIS K 6924-1.

The ethylene-vinyl acetate copolymer (A) has a melt flow rate of 1 to 30 g / 10 minutes measured at a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K 6924-1. Is preferable, and particularly preferably 3 to 15 g / 10 minutes. When the melt flow rate is 1 g / 10 minutes or more, the obtained sealant adhesive is preferable because it has excellent molding processability and adhesive strength. On the other hand, when the melt flow rate is 30 g / 10 minutes or less, the obtained sealant adhesive is preferable because it is excellent in molding process stability.

The ethylene-vinyl acetate copolymer (A) can be obtained by a known production method, or a commercially available product may be used. Specific examples include (trade name) Ultrasen 515, Ultrasen 537, Ultrasen 540, Ultrasen 541 (manufactured by Tosoh Corporation) and the like.

The ethylene-vinyl acetate copolymer (B) has a vinyl acetate content of 8 to 25% by weight, preferably 10 to 20% by weight. When the vinyl acetate content is less than 8% by weight, the obtained sealant adhesive is not preferable because it is inferior in low-temperature heat-sealing property and adhesive strength. On the other hand, when the vinyl acetate content exceeds 25% by weight, the obtained sealant adhesive is not preferable because it is inferior in molding processability and blocking property. The vinyl acetate content in the ethylene-vinyl acetate copolymer can be measured by a method measured in accordance with JIS K 6924-1.

The ethylene-vinyl acetate copolymer (B) has a melt flow rate of 1 to 30 g / 10 minutes measured at a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K 6924-1. Is preferable, and particularly preferably 3 to 20 g / 10 minutes. When the melt flow rate is 1 g / 10 minutes or more, the obtained sealant adhesive is preferable because it has excellent molding processability and adhesive strength. On the other hand, when the melt flow rate is 30 g / 10 minutes or less, the obtained sealant adhesive is preferable because it is excellent in molding process stability.

The ethylene-vinyl acetate copolymer (B) can be obtained by a known production method, or a commercially available product may be used. Specific examples include (trade name) Ultrasen 541, Ultrasen 626, Ultrasen 625, Ultrasen 633 (manufactured by Tosoh Corporation), and the like.

The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B) constituting the present invention is 3 to 20% by weight, preferably 3 to 3 to 20% by weight. It is 15% by weight. If the difference in vinyl acetate content is less than 3% by weight, the adhesive strength of the obtained sealant adhesive is inferior, which is not preferable. On the other hand, if it exceeds 20% by weight, the obtained sealant adhesive is not preferable because the molding process stability is inferior.

As the tackifier (C) constituting the present invention, any tackifier (C) can be used as long as it belongs to the category of tackifiers. For example, a petroleum resin-based or kumaron resin which is a synthetic petroleum resin-based tackifier. Examples thereof include rosin-based resins, styrene-based resins, rosin-based resins, methyl ester-based resins, glycerin ester-based resins, pentaeristol ester-based resins, terpene-based resins, and modified products thereof, which are natural resin-based tackifiers. Among these tackifiers, synthetic petroleum resin-based tackifiers include aliphatic petroleum resins, aliphatic hydrous petroleum resins, aromatic petroleum resins, aromatic hydrous petroleum resins, and alicyclic petroleum. There are resins, alicyclic hydrogenated petroleum resins, copolymerized hydrogenated petroleum resins, etc. Among these, the use of aromatic hydrogenated petroleum resin and alicyclic hydrogenated petroleum resin is preferable. In particular, 50 to 90% of at least one selected from the group consisting of aliphatic petroleum resins, aromatic petroleum resins, alicyclic hydrogenated petroleum resins and copolymerized petroleum resins is partially hydrolyzed to seal. It is preferable because it has excellent strength and adhesive strength. These can be used alone or in combination of two or more.

The tackifier (C) preferably has a softening point in the range of 90 to 140 ° C., particularly preferably 100 to 135 ° C., as measured by the ring-and-ball method. If the softening point is less than 90 ° C, the blocking resistance is inferior, and if it exceeds 140 ° C, the adhesive strength retention in a low temperature environment is inferior.

As the tackifier (C), a commercially available one is used. Specific examples include, for example, (trade name) Archon M90, Archon M115, Archon M135, Archon P100, Archon P125, Imarb S110, Imarb P125, T-REZ RC115, T-REZ HA125, Pine Crystal KE-311, YS Resin. PX1150, YS resin PX1150N and the like can be mentioned.

The blending amounts of the ethylene-vinyl acetate copolymer (A), the ethylene-vinyl acetate copolymer (B) and the tackifier (C) are as follows, and (A), (B) and (C). The total is 100 parts by weight.

The blending ratio of the ethylene-vinyl acetate copolymer (A) is 10 to 50 parts by weight, particularly 20 to 40 parts by weight because it is an adhesive for a sealant having an excellent balance between adhesive strength and molding processability. preferable. If it is less than 10 parts by weight, the molding process stability of the obtained sealant adhesive is inferior, which is not preferable. On the other hand, if it exceeds 50 parts by weight, the obtained sealant adhesive is not preferable because the adhesive strength becomes insufficient.

The blending ratio of the ethylene-vinyl acetate copolymer (B) is 10 to 50 parts by weight, particularly 20 to 40 parts by weight because it is an adhesive for a sealant having an excellent balance between adhesive strength and molding processability. preferable. If it is less than 10 parts by weight, the adhesive strength of the obtained sealant adhesive is inferior, which is not preferable. On the other hand, if it exceeds 50 parts by weight, the obtained sealant adhesive is not preferable because the molding process stability is inferior and the blocking property is also inferior.

The blending amount of the tackifier (C) is preferably 5 to 40 parts by weight, particularly preferably 15 to 30 parts by weight. If it is less than 5 parts by weight, the obtained sealant adhesive is not preferable because the sealing strength and the adhesive strength are inferior. On the other hand, if it exceeds 40 parts by weight, the roll release property at the time of molding is inferior and winding blocking occurs, which is not preferable.

Since the sealant adhesive of the present invention is particularly excellent in low-temperature sealing property and sealing strength, the density of ethylene / α ^{measured by JIS K6922-1 (1998) is in the range of 860 to 910 kg / m 3.} -It is preferable that the olefin copolymer (D) is blended. The blending amount at that time is 100 parts by weight of the total amount of the ethylene-vinyl acetate copolymer (A), the ethylene-vinyl acetate copolymer (B), and the tackifier resin (C). , 10 to 50 parts by weight of the ethylene / α-olefin copolymer (D) is preferable, and 20 to 40 parts by weight is particularly preferable.

As the ethylene / α-olefin copolymer (D), any one that belongs to the category generally referred to as an ethylene / α-olefin copolymer can be used. Although the α-olefin is not particularly limited, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecane having 3 to 12 carbon atoms are not particularly limited. Etc. can be exemplified. These ethylene / α-olefin copolymers (D) can be suitably produced by copolymerizing ethylene and α-olefin using a Cheegler catalyst, a chromium catalyst, or a metallocene catalyst. Examples of the polymerization method include a solution polymerization method, a high-pressure polymerization method, and a gas phase polymerization method. Furthermore, this ethylene / α-olefin copolymer (D) is calculated as the molecular weight of linear polyethylene by measuring a universal calibration line with monodisperse polystyrene using gel permeation chromatography under the conditions shown below. It is preferable that the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3 or less because it is excellent in low-temperature heat-sealing property and sealing strength.

Model: Waters 150C ALC / GPC
Solvent: 1,2,4-trichlorobenzene Flow rate: 1 ml / min
Temperature: 140 ° C
Measured concentration: 30 mg / 30 ml
Injection volume: 100 μl
Column: 3 TSKgel GMH HR-H manufactured by Toso Co., Ltd. Further, this ethylene / α-olefin copolymer (D) is the temperature at the maximum peak position of the heat absorption curve obtained by the temperature rise measurement by the differential scanning calorimeter. If (Tm (° C.)) and the number of short chain branches per 1000 carbon atoms (SCB) obtained from the measurement of the infrared absorption spectrum satisfy the relationship of Eq. (1), the ethylene / α-olefin copolymer weight It is preferable because the composition distribution of the coalescence is narrow and the number of low-density (high-short chain branching) components that deteriorate the low-temperature heat-sealing property is small. This is because the ethylene / α-olefin copolymer has a lower density and a lower melting point as the number of short chain branches (SCB) per 1000 carbon atoms increases. Even if the number of short chain branches is increased in order to lower the melting point, a large number of short chain branches are introduced into the low molecular weight portion, and the ethylene / α-olefin copolymer containing a large amount of low density (high short chain branches). The melting point will be high. On the other hand, even among ethylene / α-olefin copolymers having the same number of short-chain branches, those in which short-chain branches are uniformly introduced from low molecular weight to high-molecular weight have many low densities (high short-chain branches). It has a lower melting point than the ethylene / α-olefin copolymer containing it.

Tm <-1.8 x SCB + 140 (1)
Such an ethylene / α-olefin copolymer (D) can be produced, for example, by the method disclosed in the publication as illustrated below.

Japanese Patent Application Laid-Open No. 60-35006, Japanese Patent Application Laid-Open No. 60-35007, Japanese Patent Application Laid-Open No. 60-35088, Japanese Patent Application Laid-Open No. 3-1630088, Japanese Patent Application Laid-Open No. 61-296008, Japanese Patent Application Laid-Open No. 63-22804 Japanese Patent Application Laid-Open No. 58-19309, Japanese Patent Application Laid-Open No. 63-61010, Japanese Patent Application Laid-Open No. 63-152608, Japanese Patent Application Laid-Open No. 63-264606, Japanese Patent Application Laid-Open No. 63-280703, Japanese Patent Application Laid-Open No. Japanese Patent Application Laid-Open No. 64-6003, Japanese Patent Application Laid-Open No. 1-95110, Japanese Patent Application Laid-Open No. 3-629806, Japanese Patent Application Laid-Open No. 1-259004, Japanese Patent Application Laid-Open No. 64-45406, Japanese Patent Application Laid-Open No. 60-106808, Kaisho 60-137911, Japanese Patent Application Laid-Open No. 61-296008, Patent Publication No. 63-501369, Japanese Patent Application Laid-Open No. 61-221207, Japanese Patent Application Laid-Open No. 2-22307, Japanese Patent Application Laid-Open No. 2-173110, Japanese Patent Application Laid-Open No. 2-302410, Japanese Patent Application Laid-Open No. 1-129003, Japanese Patent Application Laid-Open No. 1-210404, Japanese Patent Application Laid-Open No. 3-66710, Japanese Patent Application Laid-Open No. 3-70710, Japanese Patent Application Laid-Open No. 1-207248, Japanese Patent Application Laid-Open No. Japanese Patent Application Laid-Open No. 63-222177, Japanese Patent Application Laid-Open No. 63-222178, Japanese Patent Application Laid-Open No. 63-222179, Japanese Patent Application Laid-Open No. 1-12407, Japanese Patent Application Laid-Open No. 1-301704, Japanese Patent Application Laid-Open No. 1-319489, Japanese Patent Application Laid-Open No. Kaihei 3-74412, Japanese Patent Application Laid-Open No. 61-264010, Japanese Patent Application Laid-Open No. 1-275609, Japanese Patent Application Laid-Open No. 63-251405, Japanese Patent Application Laid-Open No. 64-74202, Japanese Patent Application Laid-Open No. 2-41303, Examples thereof include Japanese Patent Application Laid-Open No. 1-31488, Japanese Patent Application Laid-Open No. 3-56508, Japanese Patent Application Laid-Open No. 3-70708, and Japanese Patent Application Laid-Open No. 3-70709.
Further, the ethylene / α-olefin copolymer (D) may be a commercially available product.

The sealant adhesive of the present invention is a blend of a thermoplastic block copolymer (E) of a vinyl aromatic hydrocarbon and an olefin or diolefin because it is particularly excellent in sealing strength and adhesive strength. Is preferable. The blending amount at that time is 100 parts by weight of the total amount of the ethylene-vinyl acetate copolymer (A), the ethylene-vinyl acetate copolymer (B), and the tackifier resin (C). The ethylene-α-olefin copolymer (D) is added to 100 parts by weight of the total amount of the ethylene-vinyl acetate copolymer (A), the ethylene-vinyl acetate copolymer (B), and the tackifier resin (C). ) Is preferably 0.5 to 5 parts by weight, particularly 1 to 4 parts by weight of the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and olefin or diolefin. It is preferable to have.

The thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and the olefin or diolefin constituting the present invention is represented by the general formulas (AB) n, (AB) n-A'or (A-). B) mX (where A and A'in the formula are vinyl aromatic hydrocarbon polymer blocks, B is an olefin or diolefin polymer block, n is an integer of 1-5, m is an integer of 2-7, X represents an m-valent polyfunctional compound), which is a polymer having a block structure having a linear structure, a radial structure, or a branched structure, at least one end of which is a vinyl aromatic hydrocarbon polymer block. , The polymer may be used. Examples of vinyl aromatic hydrocarbons used here include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, vinylxylene, ethylvinylxylene, vinylnaphthalene and mixtures thereof. Of these, styrene is particularly preferable. On the other hand, examples of olefins include α-olefins such as ethylene, propylene and 1-butene, and examples of diolefins include conjugated diolefins such as butadiene and isoprene. Further, as the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and the diolefin, a polymer block obtained by polymerizing the conjugated diolefin may be hydrogenated, and the block B may be an olefin. Polymers of conjugated diolefins and vinyl aromatic hydrocarbons may be used as long as the units are predominant. Of these, in the present invention, a thermoplastic block copolymer of a vinyl aromatic hydrocarbon having a vinyl aromatic hydrocarbon polymer block at both ends and an olefin or a diolefin is preferable, and a polystyrene-polybutadiene-polystyrene block copolymer is preferable. (Styrene-ethylene / butylene-styrene triblock copolymer, hereinafter SEBS) is particularly preferably used from the viewpoint of improving thermal stability.

Further, the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and the olefin or diolefin has a melt flow rate in the range of 10 to 70 g / 10 minutes at 200 ° C. and a load of 5.0 kg. It is preferable, and particularly preferably 12 to 65 g / 10 minutes.

Further, since the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and olefin or diolefin is an adhesive for a sealant having excellent molding processability and adhesive strength, hydrogenated styrene-butadiene-. It is a mixture of a diblock copolymer and a hydrogenated styrene-butadiene-styrene-triblock copolymer, preferably having a mixing ratio of 5/5 to 9/1, and having a styrene content of 20 to 50% by weight. It is preferable to have.

As the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and an olefin or a diolefin, a commercially available one is used. Specific examples include (trade name) Kraton G1726MS (manufactured by Kraton Polymer Co., Ltd.) and the like.

The sealant adhesive of the present invention includes other thermoplastic resins and rubbers, as well as light stabilizers, ultraviolet absorbers, nucleating agents, lubricants, antioxidants, antiblocking agents, as long as the effects of the present invention are not impaired. A fluidity improver, a mold release agent, a flame retardant, a colorant, an inorganic neutralizer, a hydrochloric acid absorber, a filler conductive agent and the like may be used.

The method for preparing the sealant adhesive of the present invention may be any method as long as the sealant adhesive can be prepared, for example, the ethylene-vinyl acetate copolymer (A) and the ethylene-vinyl acetate. Examples thereof include a method in which the copolymer (B) and the tackifier resin (C) are pre-blended at the same time with a mixer such as a Henschel mixer or a tumbler, and melt-kneaded with a single-screw or twin-screw extruder.

The sealant adhesive of the present invention is used as a container lid sealant adhesive. The container is suitable for those containing polyethylene terephthalate as the main component.

The film for a lid material of the present invention has a structure including at least two layers of a support base material layer and the above-mentioned adhesive layer for a sealant. The supporting base material constituting the supporting base material layer may be any one having self-supporting property, for example, olefin resins such as polyethylene, polypropylene and ethylene-acid copolymer resin, polyethylene terephthalate, polybutylene terephthalate and polyethylene. Polyester-based resins such as naphthalate, plastic films made of thermoplastic resins such as polyamide-based resins, paper such as Japanese paper and composite paper, metal foils made of metals such as aluminum, and single or laminated products thereof. Can be mentioned. The thickness of the support base material layer can be selected according to the application as long as the mechanical strength, workability, etc. are not impaired, but is generally about 5 to 100 μm, preferably 10 to 50 μm.

The thickness of the sealant adhesive layer can be selected depending on the application as long as the adhesiveness, workability and the like are not impaired, but is generally about 5 to 50 μm, preferably about 15 to 30 μm.

In the present invention, an intermediate layer may be provided between the support base material layer and the sealant adhesive layer in order to improve the adhesion between the two layers. This intermediate layer can be composed of components such as a thermoplastic resin such as polyolefin and a thermoplastic elastomer, and these components can be used alone or in combination of two or more. For example, as polyolefins, polyethylene and ethylene copolymers (ethylene / α-olefin copolymer, propylene-ethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, methyl ethylene-acrylate) (Copolymers, etc.) and modified products thereof. Various additives such as antioxidants, lubricants, antistatic agents, conductive agents, antiblocking agents, tackifiers and the like may be used for the intermediate layer as long as the effects of the present invention are not impaired.

The thickness of the intermediate layer can be selected according to the application as long as workability is not impaired, but is generally about 5 to 30 μm.

In the present invention, an anchor coat layer such as polyurethane is provided between the support base material layer and the sealant adhesive layer, or between the support base material layer and the intermediate layer in order to improve the adhesion between the two layers. You can also.

The film for a lid material of the present invention is suitable as a lid material for a container for A-PET, and has sealing property and easy peeling property.

The method for producing the film for the lid material is not particularly limited, and examples thereof include a method of laminating the sealant adhesive and the supporting base material layer, and a method of co-extruding the sealant adhesive and the supporting base material layer. Examples of the laminating method include (1) an extrusion laminating method in which an anchor coating agent is applied to a supporting base material layer and the adhesive layer is melt-extruded, and (2) an anchor coating agent is applied to a supporting base material layer and intermediate. An extrusion laminating method in which a layer is melt-extruded and then an adhesive layer for a sealant is melt-extruded onto the layer. (3) An intermediate layer having excellent adhesiveness to a support base material is melt-extruded into a support base material layer, and then melt-extruded. An extrusion laminating method in which an adhesive layer for a sealant is melt-extruded onto the adhesive layer, (4) a co-extrusion laminating method in which an anchor coating agent is applied to a support base material layer and an intermediate layer and an adhesive layer are melt-extruded at the same time, (5). A dry laminating method in which a film containing at least one layer of a sealant adhesive is molded in advance by an inflation molding method or a cast molding method and bonded to a support base material layer coated with an anchor coating agent, and (6) a support group coated with an anchor coating agent. Examples thereof include an extrusion laminating method in which a film containing at least one layer of a material layer and a sealant adhesive is laminated by melt-extruding an intermediate layer using extrusion laminating. On the other hand, examples of the coextrusion method include a coextrusion inflation method and a coextrusion T-die method.

The adhesive for a container lid sealant of the present invention is used for a lid material of an A-PET container having excellent molding processability, high sealing strength and adhesive strength, and excellent heat resistance, and is used as a lid material film. It is useful as.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

~ Melt Flow Rate (MFR) ~
The MFR of the ethylene-vinyl acetate copolymer (A) and the ethylene-vinyl acetate copolymer (B) was measured according to JIS K6924-1.

The moldability of the sealant adhesive obtained in the examples was evaluated by the method shown below.

~ Molding stability ~
Using an extrusion laminator (screw diameter 25 mmφ manufactured by Placo Co., Ltd.), the adhesive pellets were extruded and laminated at a processing temperature of 230 ° C. to collect a film having an adhesive layer thickness of 25 μm for a sealant. The judgment was good when there was no deviation of 3 μm or more in the film thickness after the laminating process (Δ, and ◯).

◯: There is no pulsation or rolling of the molten film and the thickness deviation is less than 3 μm, Δ: There is pulsation or rolling of the molten film but the thickness deviation is less than 3 μm, ×: There is pulsation or rolling of the molten film and the thickness deviation is 5 μm. that's all
~ Roll release property ~
Using an extrusion laminator (screw diameter 25 mmφ manufactured by Placo Co., Ltd.), the adhesive pellets are extruded and laminated so that the thickness of the adhesive layer for sealant is 25 μm at a processing temperature of 230 ° C. evaluated. The judgment was good when the film surface had no peeling marks when peeled from the roll (◯).

○: No peeling marks, ×: With peeling marks
The sealing strength and adhesive strength of the lid material film obtained in the examples were measured by the methods shown below.

~ Measurement of sealing strength ~
The adhesive surface of the film and the A-PET cup (capacity 215 ml) are overlapped and pressed using a cup sealer (Sunny Cup, model UF-500) at 160 ° C., 40 kgf / cup, for 1 second. Heat-bonded. After allowing to cool, the burst strength was measured using a seal tester (manufactured by Sun Chemical Co., Ltd., model FKT-100J) under the condition of an air injection amount of 0.8 L / min. The judgment was good at 25 kPa or more.

◯: 25 kPa or more, ×: less than 25 kPa ~ Measurement of adhesive strength ~
The adhesive surface of the film and the A-PET sheet (manufactured by Polytec) are overlapped and pressed using a heat seal tester (manufactured by Tester Sangyo Co., Ltd., TP-701 type) at 160 ° C., 0.2 MPa, and 1 second. Heat-bonded. After allowing to cool, the seal strength was measured under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min. Judgment was good when the width was 10 N / 15 mm or more.

◯: 10N / 15mm or more, ×: less than 10N / 15mm
Reference example As an ethylene-vinyl acetate copolymer (A), a resin (A1) having a vinyl acetate content of 6% and a melt mass flow rate of 8.5 g / 10 minutes (trade name: Ultrasen 537 manufactured by Tosoh Corporation) is 40 weights. Part, as an ethylene-vinyl acetate copolymer (B), a resin (B1) having a vinyl acetate content of 15% and a melt mass flow rate of 3.0 g / 10 minutes (trade name: Ultrasen 626 manufactured by Tosoh Corporation) 40 weight Part, as the tackifier resin (C), partially watered petroleum resin (C1) (trade name Archon M115 manufactured by Arakawa Chemical Co., Ltd .; softening temperature 115 ° C., watering rate about 60% (NMR method)) 20 weight The portions were pre-blended with a tumbler mixer and then melt-kneaded at 180 ° C. using a twin-screw extruder to obtain pellets of a sealant adhesive. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 9% by weight. In consideration of thermal stability, a phenolic antioxidant (manufactured by BASF Co., Ltd., trade name Irganox 1010) was added to the sealant adhesive by 0.05 parts by weight with respect to 100 parts by weight of the sealant adhesive. , 0.2 parts by weight of a slip agent (manufactured by Lion Axo Co., Ltd., product name Armowax E) was added.
The MFR of the obtained sealant adhesive was 15 g / 10 minutes.

After that, the low density of the multilayer film obtained by extruding and laminating low density polyethylene (25 μm thickness, trade name Petrosen 203 manufactured by Toso Co., Ltd.) as an intermediate layer on a biaxially stretched polyester film (12 μm thickness) which is a supporting base material layer in advance. Using an extruded laminator (screw diameter 25 mmφ manufactured by Placo Co., Ltd.) on the polyethylene surface, the adhesive pellets were extruded and laminated at a processing temperature of 230 ° C. to obtain a film for a lid material having an adhesive layer thickness of 25 μm for a sealant.

Table 3 shows the evaluation results of the obtained sealant adhesive and lid film.

Example 2
Instead of 40 parts by weight of ethylene-vinyl acetate copolymer (A1), 35 parts by weight of ethylene-vinyl acetate copolymer (A1), and instead of 40 parts by weight of ethylene-vinyl acetate copolymer (B1), ethylene-acetic acid 35 parts by weight of vinyl acetate (B1), as a tackifier resin (C), instead of 20 parts by weight of partially hydrogenated petroleum resin (C1), completely hydrogenated petroleum resin (C2) (Arakawa Chemical Co., Ltd.) Product name Alcon P125; Softening temperature 125 ° C., hydrogenation rate approx. 95% (NMR method)) 30 parts by weight, ethylene / α as an ethylene / α-olefin copolymer (D) with a density of 860 kg / m ³ -Olefin copolymer (D1) (manufactured by Mitsui Chemicals Co., Ltd., trade name Tuffmer P-0375) Obtained an adhesive for sealant and a film for lid material in the same manner as in the reference example, except that the amount was 40 parts by weight. It was. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 9% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 9 g / 10 minutes.

Table 3 shows the evaluation results of the obtained sealant adhesive and lid film.

Example 3
Instead of 35 parts by weight of ethylene-vinyl acetate copolymer (B1), ethylene-vinyl acetate copolymer (B2) having a vinyl acetate content of 10 parts and a melt mass flow rate of 9.0 g / 10 minutes (Tosoh Co., Ltd.) Product name Ultrasen 541) 35 parts by weight, as a tackifier resin (C), instead of 30 parts by weight of fully hydrogenated petroleum resin (C2), 30 parts by weight of partially hydrogenated petroleum resin (C1), ethylene / α - olefin copolymer (D1) in place of 40 parts by weight, the ethylene · alpha-olefin copolymer density is 885kg / ^{m 3} (D2) (Tosoh Co., Ltd., trade name LUMITAC BF300R) 40 parts by weight An adhesive for a sealant and a film for a lid material were obtained in the same manner as in Example 2 except that. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 4% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 13 g / 10 minutes.

Table 3 shows the evaluation results of the obtained film for lid material.

Example 4
Instead of 35 parts by weight of ethylene-vinyl acetate copolymer (A1), 40 parts by weight of ethylene-vinyl acetate copolymer (A1), and instead of 35 parts by weight of ethylene-vinyl acetate copolymer (B2), ethylene- 40 parts by weight of vinyl acetate copolymer (B2), as a tackifier resin (C), instead of 30 parts by weight of partially hydrogenated petroleum resin (C1), partially hydrogenated petroleum resin (C3) (Arakawa Chemical Co., Ltd.) Product name Archon M135; softening temperature 135 ° C., hydrogenation rate approx. 60% (NMR method)) 20 parts by weight, ethylene / α-olefin copolymer (D2) 40 parts by weight instead of ethylene / α-olefin An adhesive for a sealant and a film for a lid material were obtained in the same manner as in Example 3 except that the amount of the copolymer (D2) was 20 parts by weight. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 4% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 10 g / 10 minutes.

Table 3 shows the evaluation results of the obtained sealant adhesive and lid film.

Example 5
As the tackifier resin (C), instead of 20 parts by weight of the partially hydrogenated petroleum resin (C3), 20 parts by weight of the partially hydrogenated petroleum resin (C1) and 20 parts by weight of the ethylene / α-olefin copolymer (D2). Instead of, as 0 part by weight of ethylene / α-olefin copolymer (D2), as a thermoplastic block copolymer (E) of vinyl aromatic hydrocarbon and diolefin, melt flow at 200 ° C. and 5.0 kg load. The late is 65 g / 10 minutes, the mixing ratio of the hydrogenated styrene-butadiene-diblock copolymer and the hydrogenated styrene-butadiene-styrene-triblock copolymer is 7/3, and the styrene content is 30% by weight. An adhesive for a sealant and a film for a lid material were obtained in the same manner as in Example 4 except that the thermoplastic block copolymer (E1) (KratonG1726MS) of a vinyl aromatic hydrocarbon and a diolefin was prepared in an amount of 5 parts by weight. .. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 4% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 24 g / 10 minutes.

Table 3 shows the evaluation results of the obtained sealant adhesive and lid film.

Example 6
Instead of 40 parts by weight of ethylene-vinyl acetate copolymer (A1), 35 parts by weight of ethylene-vinyl acetate copolymer (A1), and instead of 40 parts by weight of ethylene-vinyl acetate copolymer (B2), ethylene-acetic acid Instead of 35 parts by weight of vinyl acetate (B2) and 20 parts by weight of partially hydrogenated petroleum resin (C1), 30 parts by weight of partially hydrogenated petroleum resin (C1), ethylene / α-olefin copolymer (D2) 0 40 parts by weight of ethylene / α-olefin copolymer (D2) instead of 5 parts by weight, and 5 parts by weight of thermoplastic block copolymer (E1) of vinyl aromatic hydrocarbon and diolefin. An adhesive for a sealant and a film for a lid material were obtained in the same manner as in Example 5 except that the thermoplastic block copolymer (E1) of hydrogen and diolefin was made into 2 parts by weight. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 4% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 13 g / 10 minutes.

Table 3 shows the evaluation results of the obtained sealant adhesive and lid film.

Comparative Example 1
Instead of 40 parts by weight of ethylene-vinyl acetate copolymer (A1), 80 parts by weight of ethylene-vinyl acetate copolymer (A1), and instead of 40 parts by weight of ethylene-vinyl acetate copolymer (B1), ethylene-acetic acid An adhesive for a sealant and a film for a lid material were obtained in the same manner as in the reference example except that the vinyl copolymer (B1) was 0 parts by weight.

The adhesive composition is shown in Table 2. The MFR of the obtained sealant adhesive was 23 g / 10 minutes.

Table 4 shows the evaluation results of the obtained sealant adhesive and lid film.

The obtained film for lid material was inferior in adhesive strength and sealing strength.

Comparative Example 2
Instead of 35 parts by weight of ethylene-vinyl acetate copolymer (B1), ethylene-vinyl acetate copolymer (B2) having a vinyl acetate content of 28% and a melt mass flow rate of 5.7 g / 10 minutes (Tosoh Corporation) A sealant adhesive and a cover material film were obtained in the same manner as in Example 2 except that the product name was Ultrasen 751) 35 parts by weight. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 22% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 23 g / 10 minutes.

Table 4 shows the evaluation results of the obtained sealant adhesive and lid film.

Since the obtained adhesive had poor molding stability and poor roll release property, a film for a lid material could not be obtained.

Comparative Example 3
Instead of 40 parts by weight of ethylene-vinyl acetate copolymer (A1), 20 parts by weight of ethylene-vinyl acetate copolymer (A1), and instead of 40 parts by weight of ethylene-vinyl acetate copolymer (B1), ethylene- The sealant is the same as the reference example except that 20 parts by weight of the vinyl acetate copolymer (B2) and 60 parts by weight of the partially hydrogenated petroleum resin (C1) are replaced with 60 parts by weight of the partially hydrogenated petroleum resin (C1). An adhesive for use and a film for lid material were obtained. The difference between the vinyl acetate content of the ethylene-vinyl acetate copolymer (A1) and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B1) is 4% by weight.

The adhesive composition is shown in Table 1. The MFR of the obtained sealant adhesive was 70 g / 10 minutes.

Table 2 shows the evaluation results of the obtained film for lid material.

The obtained adhesive had poor roll release property, and the film for lid material had poor sealing strength.

Claims (7)

Ethylene-vinyl acetate copolymer (A) having a vinyl acetate content of 3 to 15% by weight, 10 to 50 parts by weight, ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 8 to 25% by weight, 10 to 50 parts by weight. The acetic acid of the ethylene-vinyl acetate copolymer (A) contains 5 to 40 parts by weight of the tackifier resin (C) (the total of (A), (B) and (C) is 100 parts by weight). The difference between the vinyl content and the vinyl acetate content of the ethylene-vinyl acetate copolymer (B) is 3 to 20% by weight, and the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) is the ethylene-vinyl acetate copolymer (B). der smaller than vinyl acetate content of) Ri, (a), 100 parts by weight of the total of (B) and (C), further
10 to 50 parts by weight of the ethylene / α-olefin copolymer (D) having a density of 860 to 910 kg / m ^{3 measured by JIS K6922-1 (1998).}
Alternatively, at least one of 0.5 to 5 parts by weight of the thermoplastic block copolymer (E) of the vinyl aromatic hydrocarbon and the olefin or diolefin.
Lid sealant adhesive container characterized that you blended. Ethylene / α-olefin copolymer (D) and
The adhesive for a container lid sealant according to claim 1, wherein both a thermoplastic block copolymer (E) of a vinyl aromatic hydrocarbon and an olefin or a diolefin is blended. The adhesive for a container lid sealant according to claim 1 or 2, wherein the ethylene / α-olefin copolymer (D) satisfies the following requirements (a) to (c).
(A) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3 or less. Tm (° C.)) and the number of short chain branches per 1000 carbon atoms (SCB) obtained from the measurement of the infrared endothermic spectrum satisfy the relationship of Eq. (1).
Tm <-1.8 x SCB + 140 (1)
(C) The number of carbon atoms of the α-olefin is 3 or more and 12 or less. The thermoplastic block copolymer (E) of a vinyl aromatic hydrocarbon and an olefin or diolefin is a mixture of a hydrogenated styrene-butadiene-diblock copolymer and a hydrogenated styrene-butadiene-styrene-triblock copolymer. For the lid material sealant of the container according to any one of claims 1 to 3 , wherein the mixing ratio is 5/5 to 9/1 and the styrene content is 20 to 50% by weight. adhesive. 50 to 90% of the tackifier resin (C) is at least one selected from the group consisting of aliphatic petroleum resins, aromatic petroleum resins, alicyclic hydrogenated petroleum resins and copolymer petroleum resins. The adhesive for a container lid sealant according to any one of claims 1 to 4, wherein the adhesive is hydrolyzed. The adhesive for a lid material sealant for a container according to any one of claims 1 to 5 , wherein the container contains polyethylene terephthalate as a main component. A film for a container lid material, which comprises at least two layers of a layer made of an adhesive for a container lid material sealant according to any one of claims 1 to 6 and a support base material layer.