JP2009018420A - Thermoplastic resin multilayer laminate - Google Patents

Abstract

An object of the present invention is to provide a material for housing and packaging an article, which is capable of low-temperature thermal bonding, has a moderate thermal bonding strength to other members, is excellent in antistatic properties, and has improved its temporal sustainability. A thermoplastic resin multilayer laminate is provided.
In a laminate formed by laminating an outer film layer, an intermediate layer, and a thermal adhesive layer, the intermediate layer contains ethylene and an unsaturated carboxylic acid ester as structural units, or an ethylene copolymer thereof. A multilayer laminate comprising: a resin composition comprising:
[Selection figure] None

Description

  The present invention relates to a thermoplastic resin multilayer laminate, and more specifically, an outer film layer, an intermediate layer, and a thermal adhesive layer are laminated, and the intermediate layer includes a specific polar group as a structural unit. By comprising a polymer or a resin composition containing the same, it is remarkably excellent in interlayer adhesion without performing an anchor coat treatment between the respective layers, and an article having excellent antistatic performance, in particular, stable stability. The present invention relates to a thermoplastic resin multilayer laminate suitable as a packaging material.

Molding materials such as thermoplastic resin films used for packaging of goods, storage bags, containers, etc. often require antistatic properties to some extent, for example, strict electrostatic shielding properties Thermoplastic used for powdered food and other food packaging, pharmaceutical packaging, textile packaging, as well as molding materials such as films used for packaging materials for precision electronic parts such as semiconductor elements, bags, containers, etc. Resin film materials and the like are also required to have antistatic properties according to their applications.
In addition to the antistatic properties, thermoplastic resin molding materials such as thermoplastic resin films used for the above applications have various properties required for each application, such as delamination strength and tensile strength. In order to satisfy various properties such as optical properties, printability, heat resistance, chemical resistance, etc. in addition to mechanical properties such as elongation, bending rigidity and impact resistance, many are used in the form of laminated materials such as laminated films. .

  Conventionally, many inventions of laminates such as antistatic multilayer laminate films that meet such requirements have already been proposed. For example, Patent Document 1 discloses a polyethylene terephthalate film as a non-metallic support and an acrylic or polycarbonate type. A vinylidene chloride resin layer is interposed between a conductive layer (coating layer) in which conductive powder such as electrolytic copper powder is dispersed in a binder resin, and for powdered food packaging and pharmaceuticals for the purpose of antistatic In addition to uses such as packaging and textile product packaging, the invention of a conductive laminated film that can be used for packaging, storage, and distribution of IC parts for the purpose of electrostatic shielding is disclosed.

  Patent Document 2 discloses an outer layer film layer, a reinforcing film layer, an adhesion reinforcing layer, and a thermal adhesive layer as materials for packaging and storing precision electronic components, and the thermal adhesive layer is charged on a polyacrylate base resin. An invention of a cover tape for a polystyrene embossed carrier tape comprising a resin composition in which a tetraalkylammonium chloride is kneaded and blended as an inhibitor is disclosed.

  However, the packaging material in which the heavy metal powder is blended in the antistatic coating layer as in the invention of Patent Document 1 has a drawback that the coating layer is somewhat brittle and easily peeled off, and the heavy metal powder is in direct contact with medicines, foods, etc. From the viewpoint of the risk of alteration promotion due to catalytic action and the risk of content alteration due to photosensitization action in the case of exposure to sunlight, etc. Use in applications such as IC chips and the like that are extremely disliked by the presence of heavy metals is not preferable, and use may be restricted in this respect.

In the laminate of Patent Document 2, the outer film layer is generally composed of a film material such as polyethylene terephthalate (PET) having a relatively high melting point and high strength and rigidity.
On the other hand, the thermal adhesive layer provided for bonding to other packaging members such as carrier tape is made of a flexible and relatively low melting point thermal adhesive resin such as ethylene / vinyl acetate copolymer (EVA). It is done.
For this reason, it is difficult to laminate both layers directly and firmly join them, usually as a buffer layer that is interposed between the two layers and alleviates the discontinuity in physical properties between the outer film layer and the thermal adhesive layer. It is common to arrange an intermediate layer that plays a role.

Furthermore, in order to ensure a smooth and good peelability by firmly adhering each layer, strengthening its deformation adaptability and homogenizing and stabilizing the release of the thermal adhesive layer from the carrier tape surface when opening the tape. In general, an adhesive layer such as an anchor coating agent is further disposed between the outer layer film layer and the intermediate layer or between the intermediate layer and the thermal adhesive layer.
Incidentally, in Patent Document 2, a coating layer of a two-component curable urethane anchor coating agent is disposed between a biaxially stretched polyester film as an outer film layer and a linear low density polyethylene reinforcing film layer as an intermediate layer. A laminated film material for a cover tape is described as an example.

A conventional laminate in which an antistatic agent is mixed or applied to the heat adhesive layer (heat seal layer) as described above has a sufficient antistatic performance at the initial stage when not much time has passed since the production date.
However, when using a product that has been left for a long time after production or used as a package immediately after production, the product stored for a long time in the state of the package was treated with an anchor coat especially on the intermediate layer. In some cases, the antistatic performance gradually decreases, and when it is used, the inconvenience of dust adhering due to static electricity generated by peeling may not be completely prevented, and this antistatic performance may deteriorate over time. It has been a problem for some time.
In particular, in recent years, as high integration of ICs, LSIs, etc. and miniaturization of other electronic components have progressed, the improvement has been strongly demanded in the industry.
JP 2000-353427 A Japanese Patent No. 3731092

The present inventors have sufficient delamination strength without applying an anchor coat treatment, etc., and can be thermally bonded at a temperature as low as possible without affecting the stored article, and for antistatic purposes. In order to develop a laminated body that does not use a brittle metal powder-mixed conductive coating layer and that has no deterioration over time in antistatic performance and is excellent in stability and stability, the inventors have conducted extensive research.
As a result, a laminate having a layer structure in which an intermediate layer made of a specific ethylene copolymer containing an unsaturated carboxylic acid ester or a resin composition containing it is disposed as an adhesion reinforcing layer between the outer film layer and the thermal adhesive layer. Based on this finding, the present inventors have found that the body can solve all the above-mentioned problems.

  Therefore, the object of the present invention is to have sufficient delamination strength without performing an anchor coat treatment and the like, and can be thermally bonded at a low temperature and improve the antistatic property, in particular, its sustainability over time. It is in providing the laminated body for the made article packaging material.

  According to the present invention, in a laminate formed by laminating an outer layer film layer, an intermediate layer and a thermal adhesive layer, the intermediate layer contains an ethylene copolymer containing ethylene and an unsaturated carboxylic acid ester as structural units, or A multilayer laminate comprising the resin composition containing the same is provided.

  The outer film layer is preferably made of a polyester resin.

  Further, an ethylene copolymer containing ethylene and an unsaturated carboxylic acid ester constituting the intermediate layer as structural units, or a resin composition containing the ethylene copolymer, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer or A blend of an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer and an ethylene / unsaturated carboxylic acid copolymer or an ethylene / unsaturated carboxylic acid ester copolymer is preferred.

  In particular, the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer is an ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, and the ethylene / unsaturated carboxylic acid copolymer is ethylene. A (meth) acrylic acid copolymer and an ethylene / unsaturated carboxylic acid ester copolymer that is an ethylene / (meth) acrylic acid ester copolymer are preferred.

  Moreover, it is particularly preferable that the thermal adhesive layer contains an antistatic agent.

  Furthermore, the thermal adhesive layer is preferably made of an ethylene / vinyl acetate copolymer resin composition containing an antistatic agent.

  The laminate of the present invention is suitably used as a carrier tape cover tape material.

The laminate of the present invention comprises an outer film layer made of a polyester resin film and the like, an ethylene copolymer containing an unsaturated carboxylic acid ester as a structural unit, or an intermediate layer made of a resin composition containing the same, and an antistatic agent-containing ethylene Vinyl acetate copolymer resin composition, etc., preferably, a thermal adhesive layer containing a nonmetallic antistatic agent is laminated, and the intermediate layer connecting the outer film layer and the thermal adhesive layer is extremely adhesive Therefore, sufficient interlayer adhesion strength is maintained without interposing an anchor coating agent coating layer between the outer layer film layer / intermediate layer and the like.
Of course, the thermal adhesive layer can be peeled off from other members when enclosing the package storage object, and can be thermally bonded at a low temperature that does not affect the package storage object. In addition, the adhesive strength with other members, for example, has a moderate and non-uniform strength that can achieve smooth peeling at the time of peeling and opening, and also has excellent antistatic properties, in particular, its (antistatic) aging It is remarkably excellent in stable stability.
Therefore, the multilayer laminate of the present invention can be suitably used for a wide range of packaging applications such as powdered foods and other food packaging, pharmaceutical packaging, textile packaging, etc., and strict electrostatic shielding properties are strongly required. It is also suitable as a cover tape material for carrier tape that stores packaging materials for precision electronic components such as semiconductor elements, bag materials, container materials, etc., for example, IC chips,

Hereinafter, preferred embodiments of the present invention will be described in detail and specifically.
As described above, the thermoplastic resin multilayer laminate of the present invention has an outer film layer, an intermediate layer and a thermal adhesive layer, and the intermediate layer contains ethylene and an unsaturated carboxylic acid ester as structural units. It is characterized by being comprised with the polymer or the resin composition containing it.

In the present invention, as the material of the outer film layer, a known thermoplastic resin film can be used, a polyester resin film such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, a polyolefin resin film such as polypropylene, and a nylon. A polyamide resin film, a polycarbonate resin film, etc. can be illustrated.
Among these, a polyester resin film is preferable, and a polyethylene terephthalate film that is excellent in strength and heat resistance, has a relatively high rigidity, and can easily obtain a transparent product is particularly preferable.
These films can be either stretched or unstretched, but biaxially stretched films are preferred.

  These films are preferably subjected to an antistatic treatment, and for example, a film in which an antistatic agent is kneaded or a film in which an outer surface is treated with an antistatic coating is suitable.

  In order to further strengthen and stabilize the adhesive strength between the intermediate layer, the surface in contact with the adhesion reinforcing layer may be subjected to surface treatment such as sandblasting, corona treatment, plasma treatment, flame treatment, ultraviolet treatment, If necessary, conventional additives such as antioxidants, ultraviolet absorbers, lubricants, antiblocking agents, softeners, rust inhibitors and the like may be added to the layer.

  The thickness of the outer film layer is appropriately set depending on the contents and use, but is usually 5 to 50 μm, preferably 9 to 30 μm.

  In the present invention, the intermediate layer is interposed between the outer layer film layer and the thermal adhesive layer, and even when the anchor coat treatment is not performed between the outer layer or the thermal adhesive layer, the intermediate layer is interposed between the outer layer and the thermal adhesive layer. It has a function of strengthening and stabilizing the adhesion between the thermal adhesive layers.

In the present invention, an ethylene copolymer containing ethylene and an unsaturated carboxylic acid ester as constituent units or a resin composition containing the same is used as a constituent material of the intermediate layer.
The laminate of the present invention in which the copolymer or resin composition is disposed in the adhesion reinforcing layer without using an anchor coating agent is remarkably excellent in antistatic properties, particularly in its stability and sustainability.

Next, an ethylene copolymer containing an unsaturated carboxylic acid ester component used as a constituent material of the intermediate layer in the present invention as a polymer component or a resin composition containing the ethylene copolymer will be described more specifically.
First, as an ethylene copolymer containing an unsaturated carboxylic acid ester as a polymer component (monomer unit of the polymer), an ethylene / unsaturated carboxylic acid ester copolymer, that is, ethylene and, for example, methyl acrylate, Copolymers with unsaturated carboxylic acid esters such as ethyl acrylate, isobutyl acrylate, nbutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, glycidyl methacrylate, dimethyl maleate, and ethylene / unsaturated carboxylic acids Acid / unsaturated carboxylic acid ester copolymer, that is, ethylene and unsaturated carboxylic acid esters and unsaturated carboxylic acids as described above, for example, acrylic acid, methacrylic acid, monoethyl maleate, maleic anhydride, etc. Mention may be made of multi-component copolymers.

  In addition to the above-mentioned copolymer blends, the resin composition includes blends with other types of polymers, such as the above-mentioned copolymers and polyethylene, ethylene / α-olefin copolymers, ethylene / unsaturated carboxylic acids. Copolymers, their ionomers, blends of other ethylene polymers such as ethylene / vinyl acetate copolymers, and polymers of olefins having 4 or more carbon atoms such as propylene, butene, pentene, hexene, etc. Or a blend of the copolymer, a blend of the copolymer and an ethylene / polar monomer polymer or copolymer such as a copolymer of ethylene, carbon monoxide, and optionally an unsaturated carboxylic acid ester or vinyl acetate. Things can be mentioned as a suitable example.

Among these, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer having an unsaturated carboxylic acid unit content of 1 to 12% by weight and an unsaturated carboxylic acid ester unit content of 1 to 25% by weight, , An ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer having a (meth) acrylic acid unit content of 1 to 12% by weight and a (meth) acrylic acid ester unit content of 1 to 25% by weight, or Ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer and unsaturated carboxylic acid unit content of 1 to 20% by weight of ethylene / unsaturated carboxylic acid copolymer or unsaturated carboxylic acid ester unit content of 1 to 25 Blends with weight% ethylene / unsaturated carboxylic acid ester copolymer, especially ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer A blend of the polymer and an ethylene / (meth) acrylic acid copolymer or an ethylene / (meth) acrylic acid ester copolymer is preferred.
Examples of (meth) acrylic acid esters include methyl acrylate, ethyl acrylate, isobutyl acrylate, nbutyl acrylate, -2-ethylhexyl acrylate, methyl methacrylate, glycidyl methacrylate, and dimethyl maleate. it can.
In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid.

The resin constituting the intermediate layer of the present invention is an ethylene copolymer containing an unsaturated carboxylic acid ester component as a polymer component or a resin composition containing these ethylene copolymers. However, the content of unsaturated carboxylic acid ester units is preferably in the range of 1 to 25% by weight, particularly preferably 2 to 10% by weight, based on the resin weight.
If the content of the unsaturated carboxylic acid ester is less than the above lower limit, the adhesive strength with the outer layer film becomes insufficient, and when an anchor coating agent is used to compensate for it, the long-term stability and durability of the antistatic performance that is the object of the present invention is If the amount is more than the above upper limit, the softening temperature is low and stickiness may occur, causing problems during processing.

In addition, the material resin used for the intermediate layer of the present invention has a melt flow rate (MFR: conforming to JISK7210-1999, 190 ° C., 2160 g load) from 1 to 50 g / 10 min from the viewpoint of workability and layer strength. More preferably, about 3-20 g / 10 min.
The thickness of the intermediate layer is appropriately set depending on the contents and the use, but is usually 5 to 50 μm, preferably 7 to 20 μm.

In the thermal adhesive layer of the present invention, it is preferable to use a composition in which a kneading type antistatic agent or, if necessary, a tackifying resin is blended with a heat-sealable base resin.
Base resins that can be suitably used include ethylene / vinyl acetate copolymer resins, ethylene / unsaturated carboxylic acid ester copolymer resins, ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer resins, ethylene Examples include unsaturated carboxylic acid copolymer resins, polyester resins, polyamide resins, acrylic resins, polyurethane resins, polyester polyurethane resins, polyolefin resins, styrene resins, or a mixture of two or more of these. be able to.
Of these, ethylene / vinyl acetate copolymer resins are preferred.
Further, commercially available seal resins such as CMPS (trade name: Multipurpose seal resin manufactured by Mitsui DuPont Polychemical Co., Ltd.) that is transparent and excellent in low-temperature heat sealability can also be used.

In addition, examples of the kneading type antistatic agent usually incorporated in the base resin include anionic surfactants such as alkyl sulfates and alkylaryl sulfates, and cations such as quaternary ammonium salts typified by tetraalkylammonium chlorides. Nonionic surfactants such as glycerin monostearate, amphoteric surfactants such as dimethylalkylbetaine, tertiary alkylamines, etc., and tin oxide, zinc oxide, titanium oxide, carbon black, etc. Can also be used depending on the purpose and intended use.
Among these, nonionic surfactants such as glycerin monostearate are preferable as the kneading type antistatic agent by the extrusion laminating method.
The blending amount is appropriately determined depending on the kind of the antistatic agent to be used, the type of the base resin, the use, etc., but is usually about 0.1 to 5 parts by weight with respect to 100 parts by weight of the base resin.

Furthermore, a tackifier resin may be blended in the thermal adhesive layer. Examples of the tackifier resin include so-called tackifiers, which are relatively low molecular weight polyethylenes, xylene resins, hydrogenated petroleum resins, esters. Gum, coumarone resin, etc. can be illustrated, and the compounding quantity is appropriate.
The thickness of the thermal adhesive layer is appropriately set depending on the contents and the like, but is usually 5 to 50 μm, preferably 10 to 30 μm.

The thermoplastic resin multilayer laminate of the present invention is obtained by laminating each of the above layers by a method known per se.
For example, a biaxially stretched polyester resin film having an antistatic coating on the outer surface in advance is prepared as an outer film layer, and an ethylene / methacrylic acid / methacrylic acid ester copolymer ( Ester-containing copolymer resin) and an antistatic agent-containing ethylene / vinyl acetate copolymer resin composition (EVA resin composition) as a thermal adhesive layer (heat seal layer) are prepared, respectively. Laminate by extrusion laminator.
That is, the ester-containing copolymer resin is extruded from the extruder onto the opposite side (uncoated surface) coated with the antistatic agent of the biaxially stretched polyester resin film and laminated on the uncoated surface of the biaxially stretched polyester resin film. .

At this time, the polyester resin film is usually subjected to corona treatment on the surface on which the intermediate layer is laminated, and inline corona treatment is desirable from the viewpoint of stability of adhesive strength.
In addition to corona treatment, plasma treatment, flame treatment, UV treatment and other treatments that activate the substrate film surface and ozone treatment on the surface of the interlayer molten resin are effective for the purpose of strengthening the adhesive strength with the substrate film. Can be used for
Then, the surface activation treatment surface such as the corona treatment of the polyester resin film and the ester-containing copolymer resin from the extruder are laminated at the lamination part of the extrusion laminating apparatus, and further to the ester-containing copolymer resin surface. The multilayer adhesive body of the present invention can be obtained by sequentially laminating the thermal adhesive layer resin.
The multilayer laminate of the present invention is excellent in antistatic property and its stability and sustainability, and can be suitably used for packaging a wide range of articles such as food packaging, pharmaceutical packaging, and textile product packaging. This is useful as a packaging material for precision electronic components such as semiconductor elements, bag materials, container materials, and especially as a cover tape material for carrier tapes for storing IC chips and the like.

  The present invention will be specifically described by the following examples, but the present invention is not limited to these examples.

"Production of laminate samples"
A biaxially stretched polyethylene terephthalate film (PET: thickness 25 μm) is prepared as an outer layer film material. Separately, as an intermediate layer material, an ethylene / methacrylic acid / isobutyl acrylate copolymer (ternary EMAAAiBA: methacrylic acid content 4 wt. %, Isobutyl acrylate content 7.5% by weight, density 930 kg / m ³ , MFR 14 g / 10 min) and thermal adhesive layer material, 100 parts by weight of ethylene / vinyl acetate copolymer tackifier (Arakawa Chemical Industries) Using an ethylene / vinyl acetate copolymer resin composition (antistatic agent-containing EVA resin) obtained by mixing 12 parts by weight of Alcon AM1) and 0.5 parts by weight of an antistatic agent glycerin fatty acid ester antistatic agent These are extruders (65 mmφ, L / D = 28), screws (3-stage type, groove depth ratio = 4) .78), using a die (900 mm width, inner dekel type), laminated under conditions of processing speed 80 m / min, resin temperature (ternary EMAAAiBA: 315 ° C., EVA resin: 220 ° C.), processing width 500 mm did.

In the lamination, the inner surface of the biaxially stretched polyethylene terephthalate film is subjected to corona discharge treatment with a discharge treatment strength of 4 kw, the ternary EMAAAiBA resin (adhesion reinforcing layer side surface) is laminated on the corona treated surface, and further on the ternary EMAAiBA resin surface The antistatic agent-containing EVA resin was sequentially laminated with an extrusion laminator to obtain a laminate sample having the following three-layer structure.
Layer structure of laminate sample: PET (25 μm) / corona treatment / ternary EMAAiBA (15 μm) / EVA easy peel resin with antistatic agent (15 μm)

"Evaluation of anti-static performance of laminate material samples"
The laminate sample was stored under the conditions of 23 ° C. and relative humidity (RH) 50%, and the time-dependent change of the surface specific resistance value was measured for the sample with a measuring instrument (Hirester UP (manufactured by Mitsubishi Chemical)). .

[Example 1]
Thermal adhesives for stored samples at 23 ° C. and RH 50% in the above layer structure (PET (25 μm) / corona treatment / ternary EMAAAiBA (15 μm) / anti-static EVA-containing easy peel resin (15 μm)) The surface resistivity of the layer surface was measured over time.
A good surface specific resistance value was exhibited 1 day after the film was produced, and no deterioration with time was observed.
The results are shown in Table 1.

[Comparative Example 1]
Low-density polyethylene (PE: Mirason 16P: density 923 kg / m ³ , MFR 3.7 g / 10 min) (15 μm) was used instead of the ternary EMAAiBA (15 μm) as the intermediate layer resin in the layer-constituting sample of Example 1. In addition, instead of the corona treatment on the inner surface side of the outer layer film material (PET (25 μm)), an anchor coating agent coating treatment (AC agent: manufactured by Dainichi Seika; Seikadyne 2710A / C; two-component reaction type) is applied to the surface. About the laminated body sample processed and stored like Example 1 except having applied and dried, the surface specific resistance value of the heat | fever adhesive layer surface was measured.
The results are shown in Table 1.
From the results of Table 1, it can be seen that the product of the example always has a surface specific resistance value that is an order of magnitude lower than that of the product of the comparative example, and is excellent in antistatic properties, in particular, its aging sustainability.

Claims (7)

In a laminate formed by laminating an outer film layer, an intermediate layer and a thermal adhesive layer,
The multilayer laminate is characterized in that the intermediate layer is composed of an ethylene copolymer containing ethylene and an unsaturated carboxylic acid ester as structural units or a resin composition containing the ethylene copolymer.   The laminate according to claim 1, wherein the outer film layer is made of a polyester resin.   An ethylene copolymer containing ethylene and an unsaturated carboxylic acid ester constituting the intermediate layer as structural units, or a resin composition containing the ethylene copolymer, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer, or ethylene / The laminate according to claim 1 or 2, which is a blend of an unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer and an ethylene / unsaturated carboxylic acid copolymer or an ethylene / unsaturated carboxylic acid ester copolymer.   The ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer is an ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, and the ethylene / unsaturated carboxylic acid copolymer is ethylene / ( The laminate according to claim 3, wherein the laminate is a (meth) acrylic acid copolymer, and the ethylene / unsaturated carboxylic acid ester copolymer is an ethylene / (meth) acrylic acid ester copolymer.   The laminate according to any one of claims 1 to 4, wherein the thermal adhesive layer contains an antistatic agent.   The laminate according to any one of claims 1 to 5, wherein the thermal adhesive layer comprises an ethylene / vinyl acetate copolymer resin composition containing an antistatic agent.   The laminate according to any one of claims 1 to 6, which is used as a cover tape for a carrier tape.