JP2017186460A - Additive for sealant and easily peelable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive for sealant excellent in low temperature heat seal property and capable of exhibiting good peeling property and antistatic properties after storage under high temperature and high humidity environment in addition to having no fuzz of a paper-made container during peeling.SOLUTION: There is provided an adhesive for sealant consisting of an ethylene-vinyl acetate copolymer (A) having vinyl acetate percentage content measured by JIS K6924-1 in a range of 3 to 18 wt.% and melt mass flow rate measured by JIS K6924-1 in a range of 5 to 40 g/10 min. of 78 to 94.8 wt.%, a tackifier (B) having softening point measured by a ring and ball method of 90°C to 140°C of 5 to 20 wt.% and an antistatic agent (C) containing at least organoboron compound of 0.2 to 2 wt.%.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive for sealants comprising a composition containing an ethylene-vinyl acetate copolymer, and more particularly to an adhesive for lid sealants suitable for paper containers and an easily peelable film. It is.

  Conventionally, plastic containers such as polyethylene, polypropylene, polystyrene, and paper containers mainly made of paper have been used for packaging foodstuffs and industrial parts, and the lid has an appropriate heat seal strength, In addition, an easily peelable film having a smooth peeling performance at the time of peeling is used. Among them, lids for paper food containers and cover tapes for carrier tapes for transporting electronic components are required to have a peeled appearance that does not peel off, so that the paper in the container peels off and fluffs at the time of peeling. . Especially for cover tapes, low-temperature heat-sealability that can provide high peel strength with a short sealing time for high-speed filling suitability, and very small electronic components stick to the cover tape or pop out when the parts are removed. Antistatic properties are required to prevent defective takeout. In recent years, chip-type electronic components have become smaller and lighter in weight, so that problems such as sticking and popping of electronic components to cover tape due to charging and peeling charging that were not a problem in the past, and high temperature and humidity There is a need for a problem that the antistatic performance deteriorates after being stored in various environments, such as the environment, and the problem of removal failure occurs. Is getting higher. As an adhesive for a container lid sealant, a mixture in which a tackifier is added to polyethylene or an ethylene-vinyl acetate copolymer (for example, see Patent Document 1), an uncharged potassium ionomer (for example, see Patent Document 2), and the like. Is used. However, none of these filling machines that have increased in speed are satisfactory in terms of low-temperature heat sealability and fluff prevention, and in addition to these, when stored in a high-temperature and high-humidity environment, the peel strength greatly increases and fluffing occurs. As a result, not all of the properties such as the maintainability of the peeling properties were satisfactory.

As for antistatic properties, it is generally performed by adding a surfactant represented by glycerin fatty acid ester or the like, but when glycerin fatty acid ester is used alone, In addition, a cover tape having stable antistatic performance, which is likely to be deteriorated in antistatic performance due to storage in a high-temperature and high-humidity environment or a change with time, has not been obtained. In addition, there is a method of kneading a polymer type antistatic agent containing a polyether structure (see, for example, Patent Document 3). However, since the polymer type antistatic agent needs to be blended in a large amount, the adhesive strength tends to be low. In addition, there is a problem that the cost is significantly increased due to the high price.
Therefore, it has excellent low-temperature heat sealability that is suitable for high-speed filling, and there is no fuzzing of the paper container at the time of peeling, as well as good peeling strength and antistatic effect even after storage in normal temperature or high temperature and high humidity environment The adhesive for sealants which shows this, and the easily peelable film were desired.

JP-A-60-105260 JP-A-9-175592 Patent No. 5106208

  However, none of the above methods is satisfactory for paper containers, particularly paper carrier tapes made of paper base materials, which are suitable for high-speed filling, low temperature heat sealability, and prevention of fluffing of paper containers at the time of peeling. In addition, since the antistatic property is greatly deteriorated by storage in a high temperature and high humidity environment, not all of them including the maintenance of the peeling characteristics and the antistatic effect are sufficiently satisfied.

  The present invention is a sealant that has excellent low temperature heat-sealing properties and has no fluffing of paper containers at the time of peeling, and can exhibit good peeling properties and antistatic properties even after storage in a high temperature and high humidity environment. It is an object to provide an adhesive for use and an easily peelable film.

  Accordingly, as a result of intensive studies on the above problems, the present inventors have found that an adhesive for sealant comprising a composition containing a specific ethylene-vinyl acetate copolymer, a tackifier and a specific antistatic agent is a low-temperature heat. In order to complete the present invention, it has been found that it has excellent sealing properties and has no fluffing of the paper container at the time of peeling, and also exhibits good peeling properties and antistatic properties even after storage in a high temperature and high humidity environment. It came.

  That is, the present invention is an ethylene having a vinyl acetate content measured by JIS K6924-1 in the range of 3 to 18% by weight and a melt mass flow rate measured by JIS K6924-1 in the range of 5 to 40 g / 10 min. -Vinyl acetate copolymer (A) 78 to 94.8% by weight, tackifier (B) having a softening point measured by the ring and ball method of 90 ° C to 140 ° C 5 to 20% by weight, and at least an organoboron compound An adhesive for sealant comprising a composition containing 0.2 to 2% by weight of antistatic agent (C) (total of (A), (B) and (C) is 100% by weight), and an easily peelable film It is.

  The present invention is described in detail below.

  The adhesive for sealants of the present invention has a vinyl acetate content measured in accordance with JIS K6924-1 in the range of 3 to 18% by weight, and a melt mass flow rate measured in accordance with JIS K6924-1 in the range of 5 to 40 g / 10 minutes. The ethylene-vinyl acetate copolymer (A) is 78 to 94.8% by weight, the tackifier (B) is 5 to 20% by weight with a softening point measured by the ring and ball method of 90 to 140 ° C., and at least organoboron An antistatic agent containing a compound (C) is composed of a composition containing 0.2 to 2% by weight (the total of (A), (B) and (C) is 100% by weight).

  The ethylene-vinyl acetate copolymer (A) constituting the present invention is an ethylene-vinyl acetate copolymer (EVA) obtained by a known production method, and is used for low temperature heat sealability, heat seal strength, and fuzz prevention. The vinyl acetate content is 3 to 18% by weight, preferably 5 to 10% by weight because it is excellent. Here, when the vinyl acetate content is less than 3% by weight, the obtained adhesive for sealant is inferior in low-temperature heat sealability. On the other hand, when the vinyl acetate content exceeds 18% by weight, the obtained adhesive for sealant is inferior in blocking resistance in a wound film state. In addition, the vinyl acetate content rate in an ethylene-vinyl acetate copolymer can be measured by the method measured based on JISK6924-1.

  In addition, the ethylene-vinyl acetate copolymer (A) is an adhesive for sealant that is excellent in extrusion laminating property, low-temperature heat sealability and fuzz prevention of paper containers, and therefore conforms to JIS K 6924-1. The melt mass flow rate measured at a temperature of 190 ° C. and a load of 21.18 N is in the range of 5 to 40 g / 10 minutes, and particularly preferably 8 to 30 g / 10 minutes. When the melt mass flow rate is less than 5 g / 10 minutes, the drawdown property at the time of extrusion lamination is inferior. On the other hand, when the melt mass flow rate exceeds 30 g / 10 min, the obtained adhesive for sealant is inferior in extrusion lamination processing stability because the melt film is not stable.

  Specific examples of the ethylene-vinyl acetate copolymer (A) include (trade name) Ultrasen 537, Ultrasen 539, Ultrasen 526, Ultrasen 541, Ultrasen 625 (manufactured by Tosoh Corporation) and the like. Can be mentioned.

  The blending ratio of the ethylene-vinyl acetate copolymer (A) constituting the present invention is 78 to 94.8% by weight, and particularly an adhesive for sealant excellent in the balance of low temperature heat sealability, heat seal strength, and fuzz prevention. Therefore, it is preferably 80 to 90% by weight. Here, when it is less than 78% by weight, the obtained adhesive for sealant is inferior in blocking resistance in a wound film state. On the other hand, when it exceeds 94.8% by weight, the obtained adhesive for sealant has insufficient low-temperature heat sealability.

  As the tackifier (B) constituting the present invention, any tackifier can be used as long as it belongs to the category of tackifier, and imparts low temperature heat sealability and heat seal strength as a tackifier. For example, a petroleum resin-based tackifier that is a synthetic petroleum resin-based tackifier, a coumarone resin-based, a styrene-based resin, a rosin-based resin that is a natural resin-based tackifier, a methyl ester-based resin, a glycerin ester-based resin, Pentaerystol ester resins, terpene resins and modified products thereof can be used. Among these tackifiers, synthetic petroleum resin-based tackifiers include aliphatic petroleum resins, aromatic petroleum resins, alicyclic hydrogenated petroleum resins, and copolymerized petroleum resins. These can be used alone or in combination of two or more. As the tackifier (B), those having a softening point of 90 to 140 ° C. measured by the ring and ball method are used. When the softening point is less than 90 ° C., the blocking resistance in the wound film state is inferior, and when it exceeds 140 ° C., the low temperature heat sealability is insufficient.

  The blending ratio of the tackifier (B) constituting the present invention is 5 to 20% by weight, and particularly 10 to 15% by weight because it becomes an adhesive for sealant excellent in low temperature heat sealability and fuzz prevention. Is preferred. When it is less than 5% by weight, the obtained adhesive for sealant is inferior in low-temperature heat sealability. On the other hand, when it exceeds 20% by weight, fluffing occurs in the paper container at the time of peeling.

  Any antistatic agent (C) constituting the present invention can be used as long as it belongs to the category of an antistatic agent containing at least an organoboron compound. It is preferable to use an organic boron compound and a basic nitrogen compound because it has an excellent antistatic effect after storage in various environments. Mixing the upper semipolar organoboron compound (donor component) and the lower basic nitrogen compound (acceptor component) in the following general formula (1) because of its excellent antistatic effect after storage in a humidity environment It is preferably a donor-acceptor molecular compound represented by the following general formula (1) obtained by melting and reacting.

上記式中、Ｒ１、Ｒ２は、それぞれ独立に、ＣＨ_３（ＣＨ_２）_１６−ＣＯ−ＯＣＨ_２又はＨＯＣＨ_２で、かつ少なくとも一方がＣＨ_３（ＣＨ_２）_１６−ＣＯ−ＯＣＨ_２であり、Ｒ３、Ｒ４は、それぞれ独立に、ＣＨ_３、Ｃ_２Ｈ_５、ＨＯＣＨ_２、ＨＯＣ_２Ｈ_４又はＨＯＣＨ_２ＣＨ（ＣＨ_３）であり、Ｒ５はＣ_２Ｈ_４又はＣ_３Ｈ_６である。

In the above formula, R 1 and R 2 are each independently CH ₃ (CH ₂ ) ₁₆ —CO—OCH ₂ or HOCH ₂ , and at least one of them is CH ₃ (CH ₂ ) ₁₆ —CO—OCH ₂ , R 3 , R4 are each _{independently CH 3, C 2 H 5,} HOCH 2, HOC 2 H 4 or _{HOCH 2 CH (CH 3),} R5 is _C 2 _{H 4} or _C 3 _{H 6.}

  In the donor component, “δ +” indicates that polarity exists in the covalent bond in the molecule, (+) indicates that the electron donating property of the oxygen atom is increased, and (−) Indicates that the electron withdrawing property of the boron atom is strong, “→” indicates a path through which electrons are attracted, and “---” indicates a state in which the interatomic bonding force is weakened.

  The donor component has 1 to 2 straight-chain saturated hydrocarbon groups having 17 carbon atoms and is limited to a glycerin residue so that the occupied area of the semipolar bond atomic group in the crystalline state is minimized. preferable.

  In the acceptor component, one of the N-substituents is a group in which a straight-chain saturated hydrocarbon group having 17 carbon atoms is bonded to the end via an amide bond, and the remaining two N-substituents are What is a tertiary amine which is a C1-C3 hydrocarbon group or a hydroxy hydrocarbon group is preferable.

  The donor-acceptor molecular compound represented by the general formula (1) is preliminarily mixed with the ethylene-vinyl acetate copolymer (A) and the tackifier (B) constituting the present invention before the donor component and the acceptor. It is preferable to prepare the components by mixing and melting them at a molar ratio of about 1: 1 and reacting them. Further, the mixing ratio of both components is preferably 1: 0.8 to 0.8: 1, particularly preferably close to 1: 1.

  The blending ratio of the antistatic agent (C) constituting the present invention is 0.2 to 2% by weight, particularly 0.5 to 1.0% by weight because it has excellent antistatic performance and heat seal strength. It is preferable that When it is less than 0.2% by weight, the obtained adhesive for sealant is inferior in antistatic effect. On the other hand, when it exceeds 2% by weight, not only the film appearance is deteriorated but also the heat seal strength is lowered.

  The antistatic agent (C) constituting the present invention can be used in combination with other antistatic agents as long as the effect of the antistatic agent containing at least an organic boron compound is not impaired. Nonionic interfaces such as glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, polyethylene glycol crude acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide, etc. Examples include activators, polyglycerin fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethylene oxide addition amides, alkyl amines, stearyl alcohol, sodium alkyl sulfonates, and the like. These can be used alone or in combination of two or more.

  Measured at 160 ° C. using a Brookfield viscometer with respect to 100 parts by weight of the total amount of ethylene-vinyl acetate copolymer (A), tackifier (B) and antistatic agent (C) constituting the present invention. It is preferable to blend 2 to 10 parts by weight of a low molecular weight ethylene-vinyl acetate copolymer (D) having a viscosity of 50 to 1000 mPa · s.

  The low molecular weight ethylene-vinyl acetate copolymer (D) constituting the present invention is an ethylene-vinyl acetate copolymer (EVA) obtained by a known production method, which provides adhesive strength stability and is peeled off. In order to suppress the fluff of the paper container, the viscosity measured at 180 degrees using a Brookfield viscometer is preferably 50 to 1,000 mPa · s, more preferably 100 to 500 mPa · s. If the viscosity measured at 160 ° C. using a Brookfield viscometer is less than 50 mPa · s, the viscosity is too low and the molding stability of the compound is poor. If it exceeds 1,000 mPa · s, the fluffing of the paper container at the time of peeling is improved. Less effective.

  The blending ratio of the low molecular weight ethylene-vinyl acetate copolymer (D) constituting the present invention is the total amount of ethylene-vinyl acetate copolymer (A), tackifier (B) and antistatic agent (C) 100. It is preferable to mix 2 to 10 parts by weight with respect to parts by weight. In the case of 2 parts by weight or more, the effect of improving the fluffing of the paper container at the time of peeling is high. On the other hand, if it is 10 parts by weight or less, the molding stability of the blend does not decrease and the peel strength does not decrease.

  The adhesive for sealant of the present invention is within the range not impairing the effects of the present invention, and further, other thermoplastic resins and rubbers, light stabilizers, ultraviolet absorbers, nucleating agents, lubricants, antioxidants, and antiblocking agents. Fluidity improvers, mold release agents, flame retardants, colorants, inorganic neutralizers, hydrochloric acid absorbents, filler conductive agents, 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), the tackifier ( B), the antistatic agent (C), and the low molecular weight ethylene-vinyl acetate copolymer (D) are simultaneously pre-blended with a mixer such as a Henschel mixer or a tumbler and melted with a single or twin screw extruder. The method of kneading is mentioned. The antistatic agent (C) can be kneaded at a high concentration in a polyolefin resin in advance to form a master batch, and the master batch can be added during extrusion lamination processing. The polyolefin resin used as the base of the masterbatch is preferably an ethylene-vinyl acetate copolymer resin, more preferably the ethylene-vinyl acetate copolymer (A) used in the present invention.

  The adhesive for a sealant of the present invention is a film support substrate made of a thermoplastic resin having high rigidity and high heat resistance such as polyester, metal foil, etc. It is desirable to laminate in advance with a support substrate and use it as an adhesive for the sealant layer. When laminating with various supporting substrates, a method of laminating a single-layer adhesive film obtained in advance by an inflation or casting method or a multilayer adhesive film having an adhesive layer in the innermost layer by a method such as dry lamination, As in the extrusion laminating method, a method of providing a urethane anchor coating agent or the like and laminating the support base material layer in a molten state can be performed.

  The easily peelable film of this invention has a layer which consists of a support base material layer and the said sealant adhesive agent. The supporting substrate constituting the supporting substrate layer may be any material having self-supporting properties, for example, olefinic resins such as polyethylene, polypropylene, ethylene-acid copolymer resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene. Polyester resin such as naphthalate, plastic film composed of thermoplastic resin such as polyamide resin, paper such as Japanese paper and composite paper, metal foil composed of metal such as aluminum, single or laminated body of these Can be mentioned. Although the thickness of a support base material layer can be selected according to a use in the range in which mechanical strength, workability | operativity, etc. are not impaired, Generally it is about 5-100 micrometers, Preferably it is 10-50 micrometers.

  The thickness of the sealant adhesive layer can be selected according to the application within a range where the adhesiveness and workability are not impaired, but is generally about 5 to 50 μm, preferably 10 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 a thermoplastic resin such as a polyolefin-based resin, a thermoplastic elastomer, or the like, and these components can be used alone or in combination of two or more. For example, examples of polyolefin resins include polyethylene and ethylene copolymers (polyethylene, polypropylene, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl acrylate copolymers, etc.) and modified products thereof. Is mentioned. Various additives such as an antioxidant, a lubricant, an antistatic agent, a conductive agent, an antiblocking agent, and a tackifier may be used in the intermediate layer as long as the effects of the present invention are not impaired.

  Although the thickness of an intermediate | middle layer can be selected according to a use in the range which does not impair workability | operativity etc., generally it is about 5-20 micrometers.

  In the present invention, an anchor coat layer may be 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.

  The easily peelable film of the present invention is made of a paper whose main material is paper, such as a container made of crepe paper, Japanese paper, synthetic paper, composite paper, or a pulp mold container made of straw, sugar cane, etc. It is suitable as a container lid.

  The easily peelable film of the present invention is a paper container for transporting electronic components whose main material is paper, for example, multilayer paperboard mainly composed of wood pulp such as hardwood pulp and conifer pulp, and the surface thereof. It is suitable for a cover material (cover tape) of an electric component conveying paper carrier made of a multilayer paperboard coated with a surface sizing agent. Examples of the surface sizing agent include oxidized starch, cationized starch, enzyme-modified starch, hydroxyethyl etherified starch, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, styrene acrylic resin, rosin resin, and resin polymer. , And any one or a combination of these resins. Among these, a starch-based sizing agent having starch as a main component and a polyvinyl alcohol-based sizing agent having polyvinyl alcohol as a main component are particularly preferable as surface sizing agents.

  When used as a lid for an electric component transporting paper carrier, a polyethylene terephthalate resin is preferable for the support base material layer because of its excellent heat resistance, the support base material layer thickness is about 12 to 25 μm, and the sealant adhesive layer thickness is 10 to 25 μm. The degree is preferred.

  The method for producing the easily peelable film is not particularly limited, but includes a method of extrusion laminating a sealant adhesive, a method of forming a multilayer film containing at least one sealant adhesive in advance, and laminating it with a support base film, etc. Is mentioned. For example, (1) An extrusion laminating method in which an anchor coating agent is applied to a supporting base film and the adhesive layer is melt-extruded. (2) After an anchor coating agent is applied to the supporting base film and the intermediate layer is melt-extruded. (3) Extrusion laminating method in which an adhesive layer is melt-extruded thereon, (3) An intermediate layer excellent in adhesion to a supporting substrate is melt-extruded on a supporting substrate film, and then the adhesive layer is melted thereon Extrusion laminating method to extrude, (4) Coextrusion laminating method in which an anchor coating agent is applied to a supporting base film, and an intermediate layer and an adhesive layer are melt-extruded at the same time, (5) Sealant by an inflation molding method or a cast molding method in advance A method of forming a multilayer film containing at least one layer of an adhesive and bonding it to a supporting base film coated with an anchor coating agent. (6) An extrusion laminating method in which a support base film coated with an anchor coating agent and a multilayer film including at least one sealant adhesive layer are laminated by melt-extrusion of an intermediate layer using an extrusion laminate, and the like.

  The easily peelable film of the present invention is used for a lid material suitable for a container, and is particularly suitable for a paper container. Since there is no fluffing on the paper container and it has excellent antistatic performance, it can be effectively used in fields where these performances are required. For example, it can be used as a lid (generally referred to as a cover tape) for a continuous tape-like container (generally referred to as a carrier tape) containing electronic components, microchips, and the like. There are plastic tapes using polystyrene or the like as carrier tapes, but carrier tapes provided with holes or depressions for inserting parts into cardboard are often used. For example, a microcarrier is inserted into a hole or a recess in a paper carrier tape, and an easily peelable film that becomes a cover tape is heated and bonded in a short time so as to become a cover material. Then, it is carried to another process, and it moves to the process of taking out the microchip while peeling the easily peelable film at high speed. In this way, the cover tape has a low-temperature heat-sealing property that is heat-bonded in a short time, prevents flaking of the peeled paper fibers from adhering to the microchip, etc., and prevents fuzz at the time of peeling. Since the antistatic property which does not give is requested | required, this invention can provide the easily peelable film which can fully satisfy these. Cover tape for carrier tape of paper containers for transporting electronic parts made of easily peelable film.

  As described above, the present invention relates to an adhesive for a sealant, more specifically, a sealant adhesive suitable for a paper container, in addition to excellent low temperature heat sealability, no fluffing of the paper container at the time of peeling, In particular, it is useful as an adhesive for sealants and an easily peelable film exhibiting good peeling properties and antistatic performance after storage in a high temperature and high humidity environment.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples.

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

JIS K6924-1 is a related standard when an ethylene-vinyl acetate copolymer is used as a material, and JIS K6924-1 is a related standard when a material is polyethylene. This time, both test temperature and nominal load were measured by the test method of ISO 1133 using a melt indexer (manufactured by Takara Industries Co., Ltd.) under the same conditions. If the MFR is less than 25, use the A method (a method of cutting the resin extruded at a predetermined time and obtaining it from the weight of the resin). If the MFR is 25 or more, use the B method (the piston moves a predetermined distance). The method of obtaining from the time was used. The measurement method of method A is as follows: 6 g of a sample is placed in a cylinder of a melt indexer set at 190 ° C., a piston is set, a 2.16 kg load is applied to the resin heated to 190 ° C., and the orifice passes through 2.095 mm. Cut out the resin flowing out at the time of, and measure its weight. The MFR was calculated by converting the weight into the weight that flowed out for 10 minutes. In the measurement method of the B method, in order to obtain the melt density of the resin in advance, a load of 2.16 kg was applied to the resin heated to 190 ° C. in the same manner as the A method, and the resin flowed out when the piston moved a predetermined distance. Cut the resin and measure its weight. The melt density (g / cm ³ ) is determined from the formula of resin weight (g) / (0.711 × predetermined distance (cm)). Clean the cylinder, piston and orifice, place the sample 6g in the cylinder of the melt indexer set at 190 ° C again, set the piston, apply a load of 2.16kg to the resin heated to 190 ° C, and mark the bottom of the piston When the cylinder reaches the upper end of the cylinder, automatic measurement is started, and the time for the piston to move a predetermined distance (2.486 cm) indicated by a marked line is measured. The MFR was calculated by (426 × 2.486 × melt density) / measurement time (seconds).

  The sealant adhesive is prepared by pre-blending the ethylene-vinyl acetate copolymer (A), the tackifier (B), and the antistatic agent (C) simultaneously with a mixer such as a Henschel mixer or a tumbler. Then, melt-kneading was performed using a single-screw or twin-screw extruder (trade name: TEM50B, manufactured by Toshiba Machine Co., Ltd.) rotating in the same direction to obtain an adhesive pellet for the sealant. The melt kneading temperature was 160 ° C. as the molten resin temperature. In consideration of thermal stability, a phenolic antioxidant (trade name: Irganox 1010, manufactured by BASF Corporation) was added to the sealant adhesive in an amount of 0.05 part by weight based on 100 parts by weight of the sealant adhesive. .

  In order to prepare a composition using the adhesive pellet for the sealant, a urethane-based anchor coat agent (Takeda) was applied to a polyester film (trade name E5100, 25 μm thickness, manufactured by Toyobo Co., Ltd.) that was previously biaxially stretched. Using low-density polyethylene (trade name Petrocene 203, manufactured by Tosoh Corp.) at a resin temperature of 310 ° C. using the products manufactured by Yakuhin Kogyo Co., Ltd., trade names A3210, A3072, ethyl acetate, solid concentration 7% by weight. A substrate is prepared by extrusion lamination to a thickness of 15 μm, and the adhesive pellet for the sealant is further extruded to a thickness of 15 μm at a resin temperature of 160 ° C. on the low density polyethylene side of the substrate. An easily peelable film was obtained.

About the adhesive for sealants obtained in the examples, low temperature heat sealability, peel appearance (fluffing), maintainability of peel properties (after storage in a high temperature and high humidity environment), antistatic properties (room temperature) The antistatic property (after storage in a high temperature and high humidity environment) was measured.
~ Measurement of low temperature heat sealability ~
The adhesive surface of the easily peelable film and the paper carrier tape (made in Korea) are overlapped, taping tester (manufactured by Vanguard Systems Co., Ltd., VS-120 type), U-shaped seal bar (0.5mm width) × 2 type, seal bar length 8.2mm) under the conditions of 130 ° C, 0.1MPa, 0.1s, seal pitch 8mm, pressurizing continuously so that the end part of the seal bar slightly overlaps Glued.

  After standing to cool, the seal strength was continuously measured for a length of 150 mm under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min, and the average value was obtained. The low temperature heat sealability is evaluated to be 0.2 N / mm or more.

○: 0.2 N / mm or more ×: less than 0.2 N / mm ~ exfoliation appearance (fluffing) ~
The adhesive surface of the easily peelable film and the paper carrier tape (made in Korea) are overlaid, and a taping tester (VS-120 type, manufactured by Vanguard Systems Co., Ltd.) and a U-shaped seal bar (0.5 mm width x Heat seal conditions were adjusted using a two-type mold and a seal bar length of 8.2 mm) so that the heat seal strength was 0.3 N / mm, and pressure-heat-bonded. After standing to cool, the adhesive surface of the easily peelable film peeled off under the conditions of a peel angle of 180 degrees and a peel speed of 300 mm / min and the carrier tape surface were visually confirmed to evaluate the peeled state. ○ was considered good.

○: No fluffing on the carrier tape and no paper fiber adhesion on the film surface ×: Fluffing on the carrier tape and paper fiber adhesion on the film surface
~ Measurement of peelability maintenance (after storage at high temperature and high humidity) ~
The adhesive surface of the easily peelable film and the paper carrier tape (made in Korea) are overlapped, and a taping tester (VS-120 type, manufactured by Vanguard Systems Co., Ltd.), U-shaped seal bar (0.5 mm width x Using two types, seal bar length 8.2mm), pressurizing and heating continuously under the conditions of 130 ° C, 0.1MPa, 0.1 seconds, seal pitch 8mm so that the end part of the seal bar slightly overlaps did. The bonded sample is stored in a high-temperature and high-humidity bath at 60 ° C. and 95% RH for one day. After the sample is taken out and allowed to cool, the seal strength is 150 mm under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min. The length was measured continuously and the average value was obtained. As the maintainability of the peel strength, a value (amount of change with time) obtained by subtracting the average strength value after storage at high temperature and high humidity from the initial average strength value (before storage at high temperature and high humidity) was used. The amount of change with time was considered to be good from 0 to 0.1 N / mm.

-Measurement of antistatic properties (room temperature)-
After extrusion lamination, the easily peelable film was stored for 3 days under conditions of 23 ° C. and 50% RH, and then the surface specific resistance value of the adhesive surface was measured under conditions of 23 ° C. and 50% RH in accordance with JIS K6911. did.
The surface specific resistance value is preferably 10 ¹² Ω or less.

-Measurement of antistatic properties (after storage in high temperature and high humidity environment)-
After extrusion lamination processing, the easily peelable film was stored for 1 day under conditions of 60 ° C. and 95% RH, and then allowed to stand for 1 day under conditions of 23 ° C. and 50% RH. In accordance with JIS K6911, the measurement was performed at 23 ° C. and 50% RH.
The surface specific resistance value is preferably 10 ¹² Ω or less.

Example 1
As the ethylene-vinyl acetate copolymer (A), a resin (A1) having a vinyl acetate content of 6% and an MFR of 28 g / 10 min (trade name Ultrasen 539 manufactured by Tosoh Corporation), 84.5% by weight, adhesive 15% by weight of hydrogenated petroleum resin (B1) (trade name Alcon P125, manufactured by Arakawa Chemical Co., Ltd.) having a softening point of 125 ° C. as an imparting agent (B), and a semipolar organic boron compound as an antistatic agent (C) Antistatic agent (C1) made of a basic nitrogen compound (trade name Biomicelle BN-105, manufactured by Boron Laboratories Co., Ltd.) (R1: CH ₃ (CH ₂ ) ₁₆ —CO—OCH _{2 of the} general formula (1) , R2: CH ₃ (CH ₂ ) ₁₆ —CO—OCH ₂ , R3: CH ₃ , R4: CH ₃ , R5: C ₃ H ₆ ) 0.5% by weight is pre-blended in a tumbler mixer, Shaft extruder Used and melt-kneaded at 160 ° C. to obtain pellets of the adhesive for the sealant.

  Table 1 shows the composition of the adhesive for sealant.

The low-density polyethylene side of the bonded substrate made of biaxially stretched polyester film (25 μm thickness) and low-density polyethylene (15 μm thickness, product name Petrocene 203 manufactured by Tosoh Corporation) prepared by extrusion lamination in advance. Then, using an extrusion laminator (screw diameter 25 mmΦ manufactured by Plako Co., Ltd.), the adhesive pellet for sealant was extruded and laminated at a processing temperature of 180 ° C. to a thickness of 15 μm to obtain an easily peelable film.
The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.
Example 2
As ethylene-vinyl acetate copolymer (A), ethylene-vinyl acetate copolymer (A1) 84.5% by weight, hydrogenated petroleum resin (B1) 15% by weight, antistatic agent (C1) 0.5% by weight A resin (D1) having a viscosity of 240 mPa · s measured at 180 ° C. using a Brookfield viscometer as a low molecular weight ethylene-vinyl acetate copolymer (D) (100% by weight) manufactured by Tosoh Corporation Special Ultrasen 7A55A, 5 parts by weight of a melt mass flow rate of about 30,000 g / 10 minutes and a number average molecular weight of 2,500) were blended, and in the same manner as in Example 1, an adhesive for sealant and an easily peelable film were prepared. Obtained.

  Table 1 shows the composition of the adhesive for sealant.

The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.
Example 3
As ethylene-vinyl acetate copolymer (A), instead of ethylene-vinyl acetate copolymer (A1) 84.5% by weight, ethylene-vinyl acetate copolymer (A1) 84.0% by weight, antistatic agent (C) Adhesive for sealant and easy peeling as in Example 2 except that 1.0% by weight of antistatic agent (C1) was used instead of 0.5% by weight of antistatic agent (C1) A characteristic film was obtained.

  Table 1 shows the composition of the adhesive for sealant.

  The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.

Example 4
As an antistatic agent (C), instead of 0.5% by weight of the antistatic agent (C1), an antistatic agent comprising a semipolar organic boron compound and a basic nitrogen compound (C2) (manufactured by Boron Laboratories, Inc., A sealant adhesive and an easily peelable film were obtained in the same manner as in Example 3, except that the trade name Biomicelle BN-77 was 1.0% by weight.

  Table 1 shows the composition of the adhesive for sealant.

  The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.

Example 5
As the ethylene-vinyl acetate copolymer (A), a resin (A2) having a vinyl acetate content of 15% and an MFR of 14 g / 10 min instead of 84.5% by weight of the ethylene-vinyl acetate copolymer (A1) (Tosoh Co., Ltd. make, brand name Ultrasen 625) Except having set it to 84.5 weight%, it carried out similarly to Example 2, and obtained the adhesive agent for sealants, and an easily peelable film.

  Table 1 shows the composition of the adhesive for sealant.

  The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.

Comparative Example 1
As antistatic agent (C), instead of 0.5 wt% of antistatic agent (C1), stearic acid monoglyceride antistatic agent (C3) (trade name Riquemar S-100 manufactured by Riken Vitamin Co., Ltd.) 0.5 wt% The adhesive for sealants and the easily peelable film were obtained in the same manner as in Example 2 except that the content was%.

  Table 1 shows the composition of the adhesive for sealant.

  The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.

  The obtained easily peelable film was inferior in maintainability of the peel characteristics and antistatic performance (after storage at high temperature and high humidity).

Comparative Example 2
As antistatic agent (C), instead of 0.5 wt% of antistatic agent (C1), diethanolamide antistatic agent (C4) (trade name Riquemar HS12A manufactured by Kao Corporation) was used except 0.5 wt% Obtained the adhesive for sealants, and the easily peelable film similarly to Example 2.

  Table 1 shows the composition of the adhesive for sealant.

The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.
The easily peelable film obtained was inferior in low-temperature heat-sealability and in antistatic performance (after storage at high temperature and high humidity).

Comparative Example 3
As ethylene-vinyl acetate copolymer (A), instead of 84.5% by weight of ethylene-vinyl acetate copolymer (A1), 84.9% by weight of ethylene-vinyl acetate copolymer (A1), antistatic agent (C) Adhesive for sealant and easy peeling as in Example 2 except that 0.1% by weight of antistatic agent (C1) was used instead of 0.5% by weight of antistatic agent (C1) A characteristic film was obtained.

  Table 1 shows the composition of the adhesive for sealant.

The obtained easily peelable film was used for measurement by the above evaluation method, and the results are shown in Table 2.
The obtained easily peelable film was inferior in antistatic performance (room temperature) and antistatic performance (after storage at high temperature and high humidity).

Claims (6)

  An ethylene-vinyl acetate copolymer having a vinyl acetate content measured by JIS K6924-1 in the range of 3 to 18% by weight and a melt mass flow rate measured by JIS K6924-1 in the range of 5 to 40 g / 10 min. (A) 78-94.8% by weight, tackifier having a softening point of 90 ° C. to 140 ° C. measured by the ring and ball method (B) 5-20% by weight, and an antistatic agent (C) containing at least an organoboron compound An adhesive for sealant comprising a composition containing 0.2 to 2% by weight (the sum of (A), (B) and (C) is 100% by weight).   The adhesive for sealant according to claim 1, wherein the antistatic agent (C) comprises an organic boron compound and a basic nitrogen compound. The adhesive for sealant according to claim 1 or 2, wherein the antistatic agent (C) comprises a donor-acceptor molecular compound represented by the following general formula (1).

In the above formula, R 1 and R 2 are each independently CH ₃ (CH ₂ ) ₁₆ —CO—OCH ₂ or HOCH ₂ , and at least one of them is CH ₃ (CH ₂ ) ₁₆ —CO—OCH ₂ , R 3 , R4 are each _{independently CH 3, C 2 H 5,} HOCH 2, HOC 2 H 4 or _{HOCH 2 CH (CH 3),} R5 is _C 2 _{H 4} or _C 3 _{H 6.}   Viscosity measured at 160 ° C. using a Brookfield viscometer is 50 to 100 parts by weight of the total amount of ethylene-vinyl acetate copolymer (A), tackifier (B) and antistatic agent (C). The adhesive for sealants according to any one of claims 1 to 3, comprising 2 to 10 parts by weight of a low molecular weight ethylene-vinyl acetate copolymer (D) of 1000 mPa · s.   An easily peelable film comprising a layer made of the adhesive for sealants according to claim 1 and a support base material layer.   A cover tape for a carrier tape of a paper container for transporting an electronic component comprising the easily peelable film according to claim 5.