Adhesive resin composition and easy-to-peel film

Abstract

The adhesive resin composition comprises an ethylene-vinyl acetate copolymer (A), a linear low-density polyethylene (B) having a melt mass flow rate (MFR, JIS K 7210: 1999, 190° C., 2160 g load) of 0.01 g / 10 min to 20 g / 10 min, and a tackifier resin (C), wherein, when the entire adhesive resin composition is taken as 100% by mass, the content of the ethylene-vinyl acetate copolymer (A) is greater than 75% by mass and less than 95% by mass, and the content of the linear low-density polyethylene (B) is greater than 0% by mass and less than 15% by mass.

Description

Technical Field

[0001] The present invention relates to an adhesive resin composition and an easily peelable film. Background Art

[0002] As a packaging material, a carrier tape for transporting or storing electronic components such as microchips is known. If this carrier tape is used, electronic components that are too small to be handled can be stored and transported by accommodating them one by one in a recess provided on the carrier tape.

[0003] The carrier tape has a recessed portion that can accommodate electronic components and the like, and packaging is performed by sealing the recessed portion with a cover tape.

[0004] In addition, plastic containers or paper containers having an easily peelable cover are known as packaging materials for food and beverages such as cup noodles, jelly, and yogurt, and pharmaceuticals.

[0005] As the cover tape or cover material as described above, an easily peelable film having moderate adhesiveness and being able to be peeled off smoothly when peeled off is required.

[0006] Examples of easily peelable adhesive resin compositions used for such easily peelable films include compositions described in Patent Documents 1 and 2.

[0007] Patent Document 1 describes an easily peelable film formed by laminating the following adhesive and a base film, wherein the adhesive comprises 5 to 20 parts by weight of a tackifier resin (B) and 3 to 10 parts by weight of a low-molecular-weight ethylene-vinyl acetate copolymer (C) having a viscosity of 50 to 1,000 mPa·s as measured at 180° C. using a Brookfield viscometer, relative to 100 parts by weight of an ethylene-vinyl acetate copolymer (A) having a vinyl acetate content in the range of 3 to 18% by weight as measured in accordance with JIS K 6924-1 and a melt mass flow rate in the range of 5 to 40 g / 10 minutes as measured in accordance with JIS K 6924-1.

[0008] Patent document 2 describes an adhesive resin composition and an easily peelable film using the same, wherein the adhesive resin composition comprises the following components: (A) 39 to 84.9 wt % of an ethylene-vinyl acetate copolymer composed of 93 to 97 wt % of ethylene residue units and 3 to 7 wt % of vinyl acetate residue units and having a melt mass flow rate of 8 to 30 g / 10 min as measured in accordance with JIS K6924-1; (B) 5 to 20 wt % of an ethylene-vinyl acetate copolymer composed of 80 to 90 wt % of ethylene residue units and 10 to 20 wt % of vinyl acetate residue units; (C) 5 to 20 wt % of a low-density polyethylene; (D) 5 to 20 wt % of a tackifier resin; and (E) 0.1 to 1 wt % of an antistatic agent (E).

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2009-35645

[0012] Patent Document 2: Japanese Patent Application Publication No. 2014-25047 Summary of the invention

[0013] Problems to be solved by the invention

[0014] However, the inventors of the present application have noticed that when peeling off an easily peelable film using an adhesive resin composition containing an ethylene-vinyl acetate copolymer and a tackifier resin from an adherend, an excessive force is sometimes generated, thereby causing problems such as scattering of contents. Furthermore, the inventors of the present application have conducted in-depth research on the above-mentioned problem, and as a result, it has been found that the conventional easily peelable film has a deviation in the bonding strength to the adherend.

[0015] The present invention has been made in view of the above circumstances, and provides an adhesive resin composition capable of realizing an easily peelable film having an excellent balance between adhesiveness and peelability and capable of suppressing variations in adhesive strength to an adherend, and an easily peelable film using the same.

[0016] Means for solving problems

[0017] The inventors of the present application have repeatedly conducted intensive studies to achieve the above-mentioned problems. As a result, they have found that by including a specific ethylene-vinyl acetate copolymer, a linear low-density polyethylene having a specific viscosity, and a tackifier resin, and controlling their contents, an easily peelable film having an excellent balance between adhesion and peelability and capable of suppressing the deviation of the adhesive strength to the adherend can be achieved, thereby completing the present invention.

[0018] According to the present invention, there are provided the adhesive resin composition and the easily peelable film shown below. [1]

[0020] An adhesive resin composition comprising:

[0021] Ethylene vinyl acetate copolymer (A);

[0022] A linear low-density polyethylene (B) having a melt mass flow rate (MFR, JIS K 7210: 1999, 190°C, 2160 g load) of 0.01 g / 10 min or more and 20 g / 10 min or less; and

[0023] Tackifying resin (C),

[0024] When the entire adhesive resin composition is taken as 100% by mass,

[0025] The content of the ethylene-vinyl acetate copolymer (A) is greater than 75% by mass and less than 95% by mass,

[0026] The content of the linear low-density polyethylene (B) is greater than 0% by mass and less than 15% by mass. [2]

[0028] The adhesive resin composition according to the above [1], wherein the content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is 3% by mass or more and 15% by mass or less based on the total amount of the ethylene-vinyl acetate copolymer (A). [3]

[0030] The adhesive resin composition as described in [1] or [2] above, wherein the melt mass flow rate (MFR, JIS K 7210:1999, 190°C, 2160 g load) of the ethylene-vinyl acetate copolymer (A) is 1 g / 10 min to 100 g / 10 min. [4]

[0032] The adhesive resin composition as described in any one of [1] to [3] above, wherein, when the entire adhesive resin composition is taken as 100% by mass,

[0033] The content of the linear low-density polyethylene (B) is 3% by mass or more and less than 12% by mass. [5]

[0035] The adhesive resin composition as described in any one of [1] to [4] above, wherein the linear low-density polyethylene (B) has a density of more than 900 kg / m 3 . [6]

[0037] The adhesive resin composition as described in any one of [1] to [5] above, wherein, when the entire adhesive resin composition is taken as 100% by mass,

[0038] The content of the tackifier resin (C) is greater than 0% by mass and less than 15% by mass. [7]

[0040] The adhesive resin composition as described in any one of [1] to [6] above, wherein the content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is 1% by mass or more and 12% by mass or less based on the total amount of the adhesive resin composition. [8]

[0042] The adhesive resin composition according to any one of [1] to [7] above, wherein the adhesive resin composition has a melt flow rate (MFR, JIS K 7210: 1999, 190°C, 2160 g load) of 1 g / 10 min to 50 g / 10 min. [9]

[0044] An easily peelable film comprising a substrate layer and a heat-sealable layer provided on one side of the substrate layer.

[0045] The heat sealable layer is formed from the adhesive resin composition according to any one of [1] to [8] above.

[10]

[0047] The easily peelable film according to the above-mentioned [9], wherein the heat sealable layer is the outermost layer.

[11]

[0049] The easily peelable film according to the above-mentioned [9] or

[10] is used for bonding to a paper substrate.

[12]

[0051] The easily peelable film according to any one of [9] to

[11] , which is used as a cover tape for a paper carrier tape.

[0052] Effects of the Invention

[0053] According to the present invention, there can be provided an adhesive resin composition having an excellent balance between adhesiveness and releasability and capable of suppressing variations in adhesive strength to an adherend, and an easily releasable film using the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] [ Figure 1 ] is a cross-sectional view schematically showing an example of the structure of an easily peelable film according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In this specification, unless otherwise specified, the expression "a to b" in the description of a numerical range means a or more and b or less. For example, "1 to 5 mass %" means "1 mass % or more and 5 mass % or less".

[0056] In the numerical range recorded in stages in this specification, the upper limit or lower limit recorded in one numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in this disclosure, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiment.

[0057] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0058] The drawings are for illustration purposes only, and the shapes, dimensional ratios, etc. of the components in the drawings do not necessarily correspond to actual products.

[0059] 1. Adhesive resin composition

[0060] The adhesive resin composition of the present embodiment comprises an ethylene-vinyl acetate copolymer (A), a linear low-density polyethylene (B) having a melt mass flow rate (MFR, JIS K 7210:1999, 190°C, 2160 g load) of 0.01 g / 10 min to 20 g / 10 min, and a tackifier resin (C). When the entire adhesive resin composition is taken as 100% by mass, the content of the ethylene-vinyl acetate copolymer (A) is greater than 75% by mass and less than 95% by mass, and the content of the linear low-density polyethylene (B) is greater than 0% by mass and less than 15% by mass.

[0061] According to the adhesive resin composition according to the present embodiment, by containing the above-mentioned components, the adhesiveness and the peeling properties are well balanced, and the variation in the adhesive strength to the adherend can be suppressed.

[0062] Wherein, the adhesive resin composition of the present embodiment can be suitably used for the situation of using paper as adherend.Specifically, can enumerate the situation of using paper as the cover tape of paper carrier tape of substrate and the cover material etc. of paper container.When using paper as adherend, require to have appropriate adhesiveness (that is, the adhesiveness of the degree that paper substrate has necessary adhesiveness and can be easily peeled off when peeling off), and, there is no deviation of adhesiveness, when peeling off from paper substrate, paper peeling does not occur (that is, the paper of paper substrate will not peel off and fluff), according to the adhesive resin composition of the present embodiment, even when using paper as adherend, the balance of adhesiveness and peeling property is also excellent, and the deviation of bonding strength can be effectively suppressed.

[0063] [Melt mass flow rate]

[0064] The adhesive resin composition of the present embodiment preferably has a melt mass flow rate (MFR, JIS K 7210: 1999, 190° C., 2160 g load) of 0.1 g / 10 min or more and 100 g / 10 min or less.

[0065] Regarding the lower limit of the above-mentioned melt mass flow rate, from the viewpoint of maintaining a balance between adhesion and releasability and effectively suppressing the deviation of adhesion strength, it is further preferred to cite, in order, 1 g / 10 minutes or more, 3 g / 10 minutes or more, 5 g / 10 minutes or more, 10 g / 10 minutes or more, 17 g / 10 minutes or more, and 20 g / 10 minutes or more.

[0066] Regarding the upper limit value of the melt mass flow rate, from the viewpoint of improving the balance between adhesion and releasability and obtaining uniform adhesion strength, it is further preferred to cite, in order, less than 50 g / 10 minutes, less than 40 g / 10 minutes, less than 35 g / 10 minutes, less than 30 g / 10 minutes, less than 28 g / 10 minutes, and less than 27 g / 10 minutes.

[0067] [Vinyl acetate content]

[0068] In the adhesive resin composition of the present embodiment, the content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is preferably 1% by mass or more and 12% by mass or less based on the total amount of the adhesive resin composition.

[0069] From the viewpoint of maintaining a balance between adhesion and releasability and effectively suppressing variations in adhesive strength, the lower limit of the content of the structural unit derived from vinyl acetate in the adhesive resin composition is preferably 1.5% by mass or more, 2% by mass or more, 3% by mass or more, and 4.2% by mass or more, in that order.

[0070] From the viewpoint of improving the balance between adhesion and releasability and obtaining uniform adhesive strength, the upper limit of the content of the structural unit derived from vinyl acetate in the adhesive resin composition is preferably 11% by mass or less, 9% by mass or less, 7% by mass or less, and 5% by mass or less, respectively.

[0071] It should be noted that the content of the structural unit derived from vinyl acetate in the adhesive resin composition can be calculated from the product of the content (mass %) of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) and the content of the ethylene-vinyl acetate copolymer (A) (wherein the total amount of the adhesive resin composition is assumed to be 1).

[0072] Hereinafter, each component constituting the adhesive resin composition according to the present embodiment will be described.

[0073] <Ethylene-vinyl acetate copolymer (A)>

[0074] When the entire adhesive resin composition is taken as 100 mass %, the content of the ethylene-vinyl acetate copolymer (A) is more than 75 mass % and not more than 95 mass %.

[0075] From the viewpoint of suppressing variations in the adhesive strength to an adherend, the lower limit of the content of the ethylene-vinyl acetate copolymer (A) is more preferably 76% by mass or more, and even more preferably 77% by mass or more.

[0076] On the other hand, from the viewpoint of achieving a good balance between adhesiveness and releasability, the upper limit of the content of the ethylene-vinyl acetate copolymer (A) is more preferably 90% by mass or less, and further preferably 85% by mass or less.

[0077] In addition, in the ethylene-vinyl acetate copolymer (A) involved in the present embodiment, from the viewpoint of excellent balance between adhesiveness and releasability and suppression of variation in adhesive strength to an adherend, the content of structural units derived from vinyl acetate relative to the total amount of the ethylene-vinyl acetate copolymer (A) is preferably 3% by mass or more and 15% by mass or less.

[0078] From the viewpoint of suppressing variations in the adhesive strength to the adherend, the lower limit of the content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is more preferably 3.5% by mass or more, and even more preferably 4% by mass or more.

[0079] On the other hand, from the viewpoint of achieving a good balance between adhesiveness and releasability, the upper limit of the content of structural units derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is more preferably 12% by mass or less, and further preferably 10% by mass or less.

[0080] The content of the structural unit derived from vinyl acetate can be determined by heating the ethylene-vinyl acetate copolymer (A) to 500° C. or higher in an electric furnace to decompose it and then neutralizing and titrating the obtained vinyl acetate with acetic acid derived from the vinyl acetate in accordance with JIS K7192:1999.

[0081] In addition, for the ethylene-vinyl acetate copolymer (A) involved in this embodiment, from the viewpoint of excellent balance between adhesion and releasability and suppressing deviation in adhesion strength to the adherend, the melt mass flow rate (a) measured under the conditions of a temperature of 190°C and a load of 2160 g in accordance with JIS K 7210:1999 is preferably 1 g / 10 min to 100 g / 10 min.

[0082] In addition, from the viewpoint of maintaining a balance between adhesion and releasability and suppressing deviation in adhesion, the lower limit of the melt mass flow rate (a) is more preferably 3 g / 10 min or more, further preferably 5 g / 10 min or more, and particularly preferably 7 g / 10 min or more.

[0083] From the viewpoint of effectively suppressing the variation in adhesion and obtaining good processing stability, the upper limit of the melt mass flow rate (a) is more preferably 50 g / 10 min or less, further preferably 40 g / 10 min or less, and particularly preferably 30 g / 10 min or less.

[0084] The method for producing the ethylene-vinyl acetate copolymer (A) according to the present embodiment is not particularly limited, and the copolymer can be produced by a known method. For example, the copolymer can be obtained by subjecting each polymer component to free radical copolymerization under high temperature and high pressure. In addition, the ethylene-vinyl acetate copolymer (A) can also be a commercial product.

[0085] <Linear low-density polyethylene (B)>

[0086] The linear low-density polyethylene (LLDPE) (B) of the present embodiment is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, and is preferably a random copolymer.

[0087] As the α-olefin, an α-olefin having 3 to 10 carbon atoms, such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene, is preferred.

[0088] In the present embodiment, the linear low-density polyethylene (B) may be a mixture of a plurality of LLDPEs having different α-olefins, or a single LLDPE may be used.

[0089] When the adhesive resin composition as a whole is set to 100 mass%, the content of the linear low-density polyethylene (B) is greater than 0 mass% and less than 15 mass%. If the content of the linear low-density polyethylene (B) is 15 mass% or more when the adhesive resin composition as a whole is set to 100 mass%, it is difficult to achieve a balance between adhesion and releasability, which is not preferred.

[0090] From the viewpoint of suppressing variations in the bonding strength to the adherend, the lower limit of the content of the linear low-density polyethylene (B) is preferably 3% by mass or more, more preferably 6% by mass or more, and even more preferably 8% by mass or more.

[0091] On the other hand, from the viewpoint of achieving a good balance between adhesiveness and releasability, the upper limit of the content of the linear low-density polyethylene (B) is preferably 13% by mass or less, more preferably less than 12% by mass, and further preferably 11% by mass or less.

[0092] For the linear low-density polyethylene (B) of this embodiment, from the viewpoint of excellent balance between adhesion and releasability and suppression of deviation in adhesion strength with the adherend, the melt mass flow rate (b) measured at a temperature of 190°C and a load of 2160 g in accordance with JIS K 7210:1999 is 0.01 g / 10 min or more and 20 g / 10 min or less.

[0093] In addition, from the viewpoint of maintaining a balance between adhesion and releasability and suppressing variations in adhesion, the lower limit of the melt mass flow rate (b) is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, and further preferably 2 g / 10 min or more.

[0094] From the viewpoint of effectively suppressing the variation in adhesion and obtaining good processing stability, the upper limit of the melt mass flow rate (b) is preferably 15 g / 10 min or less, more preferably 10 g / 10 min or less, and further preferably 7 g / 10 min or less.

[0095] The lower limit of the density of the linear low-density polyethylene (B) is preferably 880 kg / m 3 More preferably 890kg / m 3 More preferably, 895 kg / m 3 Above, especially preferably 900kg / m 3 More than 900 kg / m 3 .

[0096] The upper limit of the density of the linear low-density polyethylene (B) is preferably 930 kg / m 3 Below, more preferably 920kg / m 3 Below, more preferably 910kg / m 3 Below, especially preferably 905kg / m 3 Below, further preferably less than 905kg / m 3 .

[0097] The melting point of the linear low-density polyethylene (B) is preferably 70°C to 140°C, more preferably 80°C to 135°C, particularly preferably 95°C to 130°C.

[0098] The melting point of the linear low-density polyethylene (B) is a melting temperature measured by a differential scanning calorimeter (DSC) in accordance with JIS K 7121 (2012).

[0099] In addition, when a plurality of melting points are shown in the DSC measurement, in the present embodiment, the largest melting point is taken as the melting point.

[0100] It should be noted that, usually, low-density polyethylene is classified into high-pressure low-density polyethylene (HPLDPE) and straight-chain (linear) low-density polyethylene (LLDPE), and high-pressure low-density polyethylene (HPLDPE) is a homopolymer of ethylene. In addition, in the present embodiment, if high-pressure low-density polyethylene (HPLDPE) is used, the deviation of bonding strength can not be effectively suppressed, which is not preferred.

[0101] The polymerization method of the linear low-density polyethylene (B) of the present embodiment can include the following methods: using a known Ziegler catalyst or metallocene catalyst, using a solution method, a slurry method, a gas phase method, etc. to polymerize ethylene and an α-olefin. In addition, for example, a method using a multi-site catalyst represented by a Ziegler-type catalyst and a method using a single-site catalyst represented by a metallocene catalyst can be cited. As a Ziegler-type catalyst, a combined catalyst composed of a high-activity titanium catalyst component and an organic aluminum compound catalyst component can be exemplified. In addition, as a metallocene catalyst, a combined catalyst composed of a metallocene compound and an organic aluminum oxide compound can be exemplified.

[0102] <Tackifying resin (C)>

[0103] The tackifier resin (C) has a function of imparting adhesiveness to the resin, and thus can facilitate adjustment of the adhesive strength of the adhesive resin composition.

[0104] The tackifying resin (C) can be selected from resins having a function of imparting adhesiveness, and examples of the tackifying resin (C) include aromatic hydrocarbon resins, alicyclic hydrocarbon resins, aliphatic hydrocarbon resins, terpene resins, rosins, styrene resins, and coumarone-indene resins.

[0105] Examples of the aromatic hydrocarbon resin include resins obtained by polymerizing a fraction containing at least one of vinyl aromatic hydrocarbons having 8 to 10 carbon atoms such as vinyltoluene, indene, and α-methylstyrene; and resins obtained by copolymerizing these fractions with an aliphatic hydrocarbon fraction.

[0106] Examples of alicyclic hydrocarbon resins include: resins obtained by cyclodimerizing and polymerizing diene components in waste C4-C5 fractions; resins obtained by polymerizing cyclic monomers such as cyclopentadiene; resins obtained by intra-ring hydrogenation of aromatic hydrocarbon resins (e.g., hydrogenated petroleum resins, etc.); and the like.

[0107] Examples of the aliphatic hydrocarbon resin include resins obtained by polymerizing fractions containing at least one of monoolefins or diolefins having 4 to 5 carbon atoms, such as 1-butene, isobutylene, butadiene, 1,3-pentadiene, and isoprene.

[0108] Examples of the terpene resin include α-pinene polymers, β-pinene polymers, dipentene polymers, terpene·phenol copolymers, α-pinene·phenol copolymers, and hydrogenated products thereof.

[0109] Examples of rosins include gum rosin, wood rosin, tall oil and other rosins, and modified products thereof. Examples of the modified products include those subjected to modification such as hydrogenation, disproportionation, dimerization and esterification.

[0110] Examples of the styrene-based resin include resinous polymers having a low molecular weight obtained by polymerizing styrene-based monomers such as styrene, vinyltoluene, α-methylstyrene, and isopropyltoluene.

[0111] The tackifier resin (C) preferably has a softening point of 85° C. to 130° C., more preferably 100° C. to 125° C., and even more preferably 110° C. to 120° C. Generally, when the softening point is 85° C. or higher, there is a tendency to exhibit an excellent effect of heat resistance, and when it is 130° C. or lower, there is a tendency to exhibit an excellent effect of imparting adhesion.

[0112] As the softening point of the tackifier resin (C), a value measured by a softening point test method (ring and ball method) in accordance with JIS K 2207 (2006) can be used.

[0113] When the entire adhesive resin composition is taken as 100 mass %, the content of the tackifier resin (C) is preferably greater than 0 mass % and less than 15 mass %.

[0114] From the viewpoint of suppressing variations in the adhesive strength to an adherend, the lower limit of the content of the tackifier resin (C) is more preferably 3% by mass or more, further preferably 5% by mass or more, and particularly preferably 7% by mass or more.

[0115] On the other hand, from the viewpoint of achieving a good balance between adhesiveness and releasability, the upper limit of the content of the tackifier resin (C) is more preferably 14 mass % or less, further preferably 13 mass % or less, and particularly preferably less than 12 mass %.

[0116] As the tackifier resin (C), commercially available products may be used, for example, hydrogenated alicyclic resins such as Alcon P140 (manufactured by Arakawa Chemical Co., Ltd., softening point: 140°C), Alcon P125 (manufactured by Arakawa Chemical Co., Ltd., softening point: 125°C), Alcon P115 (manufactured by Arakawa Chemical Co., Ltd., softening point: 115°C), Alcon P100 (manufactured by Arakawa Chemical Co., Ltd., softening point: 100°C), and Alcon P90 (manufactured by Arakawa Chemical Co., Ltd., softening point: 90°C).

[0117] <Other ingredients>

[0118] The adhesive resin composition according to the present embodiment may contain ingredients other than the above, within the range that does not impair the effect of the present invention. Other ingredients are not particularly limited, and examples thereof include antistatic agents, anti-blocking agents, slip agents, roll-off agents, antioxidants, heat stabilizers, light stabilizers, pigments, dyes, etc. Other ingredients may be used alone or in combination of two or more.

[0119] Examples of the antistatic agent include conductive polymers, nonionic surfactants, and anionic surfactants.

[0120] Examples of the anti-blocking agent include silicon dioxide and aluminosilicate (zeolite and the like).

[0121] Examples of the slip agent include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and hydrogenated castor oil. The content of the slip agent is preferably less than 1% by mass, more preferably 0.5% by mass or less, based on the total amount of the adhesive resin composition.

[0122] As the roll-off agent, there are also materials common to the above-mentioned slip agents, specifically, various amides such as palmitamide, stearamide, behenamide, oleamide, erucamide, oleyl palmitamide, stearyl palmitamide, methylenebisstearylamide, methylenebisoleamide, ethylenebisoleamide, and ethylenebiserucamide; inorganic additives such as silicon dioxide and talc, etc. The content of the roll-off agent is preferably less than 1% by mass, more preferably less than 0.5% by mass, relative to the total amount of the adhesive resin composition.

[0123] [use]

[0124] The adhesive resin composition of the present embodiment can be suitably used for bonding to a paper substrate. For example, it can be suitably used as a film that is bonded to paper such as a sealing tape or a label and is peeled off during or after use. In particular, the adhesive resin composition of the present embodiment can be suitably used as a cover tape for sealing a receiving portion for receiving a microchip or the like of a paper carrier tape that is a paper container for carrying electronic components.

[0125] Examples of the above-mentioned paper carrier tape include: a paper carrier tape in which a bottom covering tape is heat-sealed on one side (lower surface) of a storage backing paper board having a plurality of punched holes formed at regular intervals along the length direction, and the punched holes are used as recesses for accommodating electronic components; a paper carrier tape in which the storage backing paper board is embossed to form a plurality of recesses for accommodating electronic components at regular intervals along the long side direction of the storage backing paper board; and the like.

[0126] By overlaying a cover tape on the carrier tape and bonding them by heat sealing or the like, the recessed portion housing a microchip such as an IC chip can be sealed for storage and transportation.

[0127] The adhesive resin composition according to the present embodiment can also be suitably used for lid materials of packaging containers other than paper for food and beverages, pharmaceuticals, and the like.

[0128] <Method for preparing adhesive resin composition>

[0129] The preparation method of the adhesive resin composition of the present embodiment is not particularly limited, and for example, the following methods can be applied: a method of preparing by dry-blending ethylene-vinyl acetate copolymer (A), linear low-density polyethylene (B), tackifier resin (C), an antistatic agent as required, and other components; a method of preparing by melt-kneading ethylene-vinyl acetate copolymer (A), linear low-density polyethylene (B), tackifier resin (C), and other components as required using an extruder; and the like.

[0130] 2. Easy-to-peel film

[0131] Figure 1 This is a cross-sectional view schematically showing an example of the structure of the easily peelable film 50 according to the embodiment of the present invention.

[0132] The easily peelable film 50 according to the present embodiment includes a base layer 10 and a heat sealable layer 20 provided on one surface of the base layer 10 , and the heat sealable layer 20 is formed of the adhesive resin composition according to the present embodiment.

[0133] The easily peelable film of the present embodiment is preferably used as a cover tape for a paper carrier tape of a paper container for conveying electronic components.

[0134] <Base material layer>

[0135] The base material layer 10 is a layer provided for the purpose of improving the handling properties, mechanical properties, heat resistance and other properties of the easily peelable film 50 .

[0136] Examples of the substrate layer 10 include plate-like materials (sheets or films) formed of paper, aluminum, polyester (e.g., polyethylene terephthalate), polyethylene, polypropylene, polystyrene, polyamide, aluminum-deposited polyester, aluminum-deposited polypropylene, and silicon dioxide-deposited polyester. Of these, a sheet or film formed of polyethylene terephthalate is preferred. These substrate layers 10 may be not only single-layer structures but also laminated structures of two or more layers.

[0137] From the viewpoint of mechanical strength and workability, the thickness of the base layer 10 is, for example, 5 μm or more and 100 μm or less, and preferably 10 μm or more and 50 μm or less.

[0138] The substrate layer 10 may be subjected to physical treatments such as corona treatment, plasma treatment, flame treatment, ozone treatment, etc. on the surface of the side to be bonded (or laminated) with the heat sealability layer 20 in order to improve the bonding strength with the heat sealability layer 20. In addition, the substrate layer 10 may be subjected to a known anchor coating treatment.

[0139] <Heat Sealing Layer>

[0140] The heat sealable layer 20 is a layer for imparting heat sealability to the easily peelable film 50, and is formed of the adhesive resin composition according to the present embodiment.

[0141] The thickness of the heat sealable layer 20 is, for example, 1 μm to 300 μm, preferably 5 μm to 200 μm, and more preferably 10 μm to 150 μm.

[0142] The heat sealable layer 20 is preferably located on the outermost layer of the easily peelable film 50 .

[0143] <Middle Layer>

[0144] The easily peelable film 50 of this embodiment may include an intermediate layer of polyethylene or the like between the substrate layer 10 and the heat seal layer 20. The intermediate layer is provided to improve the adhesion between the substrate layer 10 and the heat seal layer 20 or to improve the processability when forming the heat seal layer 20.

[0145] 3. Method for producing easily peelable film

[0146] The method for producing the easily peelable film 50 according to the present embodiment is not particularly limited, and a molding method generally used for thermoplastic resins can be applied. For example, it can be carried out by a known method using a T-die extruder or an inflation molding machine.

[0147] For example, the adhesive resin composition according to the present embodiment can be obtained by supplying it from a hopper of a T-die extruder and extruding it into a film form on the base material layer 10 from the tip of the T-die.

[0148] In addition, the method for producing the easily peelable film 50 according to the present embodiment can be applied to a commonly used multilayer film molding method, for example, a known method using a multilayer T-die extruder or a multilayer inflation molding machine can be used.

[0149] As mentioned above, although embodiment of this invention was described, these are an example of this invention, and various structures other than the above-mentioned can also be adopted.

[0150] Example

[0151] Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples.

[0152] The details of the components used in the preparation of the adhesive resin composition are as follows.

[0153] In addition, the following "MFR" is set as follows: JIS K 7210: 1999, 190° C., 2160 g load.

[0154] <Ethylene-vinyl acetate copolymer (A)>

[0155] EVA-1: ethylene-vinyl acetate copolymer (MFR: 24 g / 10 min, ethylene content: 94.5% by mass, vinyl acetate (VA) content: 5.5% by mass)

[0156] EVA-2: ethylene-vinyl acetate copolymer (MFR: 9 g / 10 min, ethylene content: 90% by mass, vinyl acetate (VA) content: 10% by mass)

[0157] <Linear low-density polyethylene (B)>

[0158] LLDPE: linear low-density polyethylene (MFR 3.8g / 10min), density 903kg / m 3 , melting point is 98°C)

[0159] <Tackifying resin (C)>

[0160] Tackifier resin: Hydrogenated alicyclic hydrocarbon resin (Alcon P-115 manufactured by Arakawa Chemical Industries, Ltd., softening point: 115°C)

[0161] <Other polymers>

[0162] HPLDPE: High pressure low density polyethylene (MFR is 3.7g / 10min, density is 923kg / m 3 )

[0163] <Additives>

[0164] Roller release agent: Erucic acid amide (ELA, manufactured by NOF Corporation)

[0165] Slip agent: polyethylene glycol (PEG, manufactured by Nippon Seika Co., Ltd.)

[0166] [Examples 1 to 7, Comparative Examples 1 to 2]

[0167] <Preparation of Evaluation Samples>

[0168] (1) Preparation of adhesive resin composition

[0169] The components were melt-kneaded at 170°C in the proportions shown in Table 1 using a single screw extruder (65 mm φ, L / D = 28, Durmajor screw with tip), to obtain adhesive resin compositions. The obtained adhesive resin compositions were cut into pellets and used for the preparation of evaluation laminated films.

[0170] (2) Preparation of evaluation laminated film

[0171] A biaxially stretched polyethylene terephthalate (PET) film (Lumirror, manufactured by Toray Industries, Ltd., with a thickness of 25 μm) was prepared. A low-density polyethylene (density of 923 kg / m 2) with a thickness of 15 μm was laminated on the PET film via an anchor coating agent (hereinafter referred to as ac. SEIKADINE 2710A (manufactured by Dainichi Seika Industries, Ltd.) 2 mass%, SEIKADINE 2710C (manufactured by Dainichi Seika Industries, Ltd.) 4 mass%, and ethyl acetate 31 mass%, solid concentration 7 mass%) using an extruder (65 mm φ, L / D = 28), a screw (3-stage type, groove depth ratio of 4.78), and a die (900 mm width, inner Deckel type) under the conditions of an air gap of 110 mm, a processing speed of 80 m / min, and a resin temperature under the die of 320°C. 3 , MFR (according to JIS K 7210:1999, temperature is 190°C, load is 2160g) is 3.7g / 10min, melting point is 111°C) to make a laminate (laminated in the order of PET film (25μm) / ac·LDPE (15μm)).

[0172] Next, using the above-mentioned extruder, screw, and die, under the conditions of an air gap of 110 mm, a processing speed of 80 m / min, and a resin temperature under the die of 240°C, a layer (thickness of 15 μm) formed by each adhesive resin composition shown in Table 1 was stacked on the above-mentioned low-density polyethylene layer to prepare evaluation laminated films (stacked in the order of PET film (25 μm) / ac·LDPE (15 μm) / adhesive resin layer (15 μm)).

[0173] The following evaluations were performed on the obtained evaluation laminated films.

[0174] [Evaluation of Adhesion and Removability]

[0175] The adhesiveness, adhesiveness variation, and releasability when the above-mentioned evaluation laminated film was used as a cover tape for a paper carrier tape were evaluated under the following conditions.

[0176] <Sample>

[0177] Paper carrier tape (adhered object): manufactured by Daio Paper Co., Ltd., thickness 0.42 mm

[0178] <Sealing conditions>

[0179] Taping machine: VS-120 manufactured by Vanguard Systems INC.

[0180] Sealed soldering iron: 2 columns, width 0.4mm, length 16mm

[0181] Sealing temperature: 200℃

[0182] Sealing time: 0.1 seconds

[0183] Sealing times: 2 times

[0184] <Peeling Conditions (Seal Strength Measurement)>

[0185] Device: VG-35 manufactured by Vanguard Systems INC.

[0186] Peeling speed: 300mm / min

[0187] Peeling angle: 165~180°

[0188] Peeling distance: 10mm

[0189] (Adhesion Evaluation)

[0190] The seal strength was measured four times, and the average of the measured values ​​was taken as the average seal strength.

[0191] ·Judgment criteria:

[0192] C (high strength): average sealing strength greater than 40g

[0193] A (optimal): average sealing strength is 25g or more and 40g or less

[0194] B (suitable): average seal strength is 15g or more and less than 25g

[0195] C (low strength): average sealing strength is less than 15g

[0196] (Evaluation of Adhesion Deviation)

[0197] The seal strength was measured four times, and the average value of the "difference between the maximum value and the minimum value" of each measured value was taken as the seal strength deviation.

[0198] ·Judgment criteria:

[0199] A: Deviation of sealing strength is less than 10g

[0200] C: The deviation of sealing strength is greater than 10g

[0201] (Peelability Evaluation)

[0202] Procedure: The raised state of the sealing surface of the sample after peeling (seal strength measurement) under the above conditions was observed under a microscope.

[0203] ·Judgment criteria:

[0204] A: There is almost no paper fiber adhesion, or there is no paper fiber adhesion at all

[0205] B: Slight adhesion of paper fibers

[0206] C: More paper fibers attached

[0207] [Table 1]

[0208]

[0209] As can be seen from Table 1, the laminated films using the adhesive resin compositions of Examples 1 to 7 have an excellent balance between adhesiveness and releasability, and can suppress variations in adhesive strength to the adherend. In contrast, the laminated films using the adhesive resin compositions of Comparative Examples 1 to 2 have a poor balance between adhesiveness and releasability, or even when they have an excellent balance between adhesiveness and releasability, they cannot suppress variations in adhesive strength to the adherend.

[0210] From the above, it was confirmed that the adhesive resin composition according to the present embodiment can realize a laminated film having an excellent balance between adhesiveness to an adherend and releasability and suppressing variation in adhesive strength to an adherend.

[0211] This application claims priority based on Japanese patent application No. 2020-160522, filed on September 25, 2020, the disclosure of which is incorporated herein in its entirety.

[0212] Description of Reference Numerals

[0213] 10. Base material layer

[0214] 20 Heat sealing layer

[0215] 50 Easy-to-peel film

Claims

1. An adhesive resin composition comprising: Ethylene vinyl acetate copolymer (A); A linear low-density polyethylene (B) having a melt mass flow rate MFR of 0.01 g / 10 min or more and 20 g / 10 min or less as measured under the conditions of a temperature of 190° C. and a load of 2160 g in accordance with JIS K 7210:1999; and Tackifying resin (C), When the entire adhesive resin composition is taken as 100% by mass, The content of the ethylene-vinyl acetate copolymer (A) is greater than 75% by mass and less than 95% by mass, The content of the linear low-density polyethylene (B) is greater than 0% by mass and less than 15% by mass, The content of the tackifying resin (C) is greater than 0% by mass and less than 15% by mass. The content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is 3% by mass or more and 15% by mass or less relative to the total amount of the ethylene-vinyl acetate copolymer (A), The ethylene-vinyl acetate copolymer (A) has a melt mass flow rate MFR of 1 g / 10 min to 100 g / 10 min, as measured under the conditions of a temperature of 190° C. and a load of 2160 g in accordance with JIS K 7210:1999.

2. The adhesive resin composition according to claim 1, wherein When the entire adhesive resin composition is set to 100 mass %, The content of the linear low-density polyethylene (B) is 3% by mass or more and less than 12% by mass.

3. The adhesive resin composition according to claim 1 or 2, wherein The density of the linear low-density polyethylene (B) is greater than 900 kg / m 3 .

4. The adhesive resin composition according to claim 1 or 2, wherein The content of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer (A) is 1% by mass or more and 12% by mass or less based on the total amount of the adhesive resin composition.

5. The adhesive resin composition according to claim 1 or 2, wherein The adhesive resin composition has a melt flow rate MFR of 1 g / 10 min to 50 g / 10 min, as measured under conditions of a temperature of 190° C. and a load of 2160 g in accordance with JIS K 7210:1999.

6. An easily peelable film comprising a substrate layer and a heat-sealable layer provided on one side of the substrate layer, The heat sealable layer is formed from the adhesive resin composition according to any one of claims 1 to 5.

7. The easily peelable film according to claim 6, wherein The heat sealable layer is the outermost layer.

8. The easily peelable film according to claim 6 or 7, which is used for bonding to a paper substrate.

9. The easily peelable film according to claim 6 or 7, which is used as a cover tape for a paper carrier tape.

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