JP4478466B2 - Resin stretched film - Google Patents

Description

  The present invention is made by an in-mold molding label or a heat seal which is adhered to a thermoplastic resin container manufactured by differential pressure molding, hollow molding, injection molding, foam molding, stretch blow molding or compression molding at the same time as container molding. The present invention relates to a stretched resin film provided with a water-based heat-sealable resin coat layer (E) that can be used for various packaging bags and products obtained using the same.

  2. Description of the Related Art In-mold molding labels have been conventionally developed for applications that require water resistance, chemical resistance, durability, and the like. For example, various heat-sealable resin layers on one side of a transparent film made of stretched or unstretched polyolefin resin, or a white film (synthetic paper) made of stretched or unstretched polyolefin resin blended with inorganic fine powder or organic filler Co-extruded in the film manufacturing process (Patent Document 1), pasted or laminated heat-sealable resin film embossed in advance, and coated with heat-sealable resin on the surface using various coating equipment (Patent Document 2) etc. have been developed and commercialized in part.

  These conventional in-mold molding labels are embossed on the surface of the heat seal resin layer during the production process or a pre-embossed film is pasted to release air trapped between the molding container and the label during in-mold molding. It was necessary to combine or laminate, or to provide a trapezoidal pattern during coating. Moreover, when the pattern for releasing these air cannot be formed in the surface, the method (patent document 3) which opened the pore to label itself and released air was proposed. However, either method complicates the manufacturing process, and problems such as a decrease in productivity, an increase in the number of defective products, and an increase in manufacturing cost cannot be avoided.

In the conventional method of providing a heat-sealable resin layer by co-extrusion during the production process of in-mold molding labels, the heat-sealable resin used has a heat-resisting, corrosive, and viscosity characteristics when melted. There was also the problem of being restricted.
Furthermore, in the case of using the conventional method of coating with various coating facilities, when trying to coat a heat-sealable resin on the surface of the base film that has been previously embossed (Patent Document 4), the solvent absorbability of the base film Therefore, most of the coating agent gathers in the concave portions of the embossing applied to the base film during drying, which makes it difficult to reproduce the embossed shape on the coat surface. When using a film that does not absorb water, apply a hot melt resin or solvent heat seal resin paint in a highly viscous state with a gravure coater and apply the trapezoidal pattern of the engraving roll cell to the substrate surface. Is also adopted. However, in this case as well, since a high-viscosity coating is essential, there have been problems such as an increase in production cost due to a decrease in productivity and fire and environmental pollution due to the use of an organic solvent.

JP-A-2-84319 JP-A-2-122914 Japanese Patent Laid-Open No. 2-108516 JP-A-5-249895

  An object of the present invention is to solve these problems of the prior art. That is, an object of the present invention is to eliminate the necessity of providing a specific pattern on the surface of the coating layer or opening through pores when the heat-sealable resin coating layer is provided on the surface of the base film. Also, to provide a stretched resin film having excellent productivity and in-mold label performance by broadening the selectivity of the material constituting the heat-sealable resin coating layer and relaxing restrictions on coating and processing equipment Was also an issue. Furthermore, another object is to provide an in-mold molding label having an excellent function and an in-mold molding container to which the label is attached.

As a result of intensive studies, the present inventors have found that a water-based heat-sealable resin coating agent is applied to the surface of a base film having a liquid absorption coefficient of 5 ml / m ² · (ms) ^1/2 or more during production. It has been found that various problems can be solved and a stretched resin film having excellent characteristics can be provided, and the present invention has been completed.
That is, the present invention relates to a stretched resin film in which a water-based heat-sealable resin coat layer (E) is provided on the surface of a base film having a liquid absorption coefficient of 5 ml / m ² · (ms) ^1/2 or more.

The surface opening ratio of the base film used in the present invention is preferably 7% or more, and is preferably stretched in at least one direction and the area stretch ratio is 2 to 80 times. Further, the base film, thermoplastic resin (A), contains at least one surface treatment agent (D) by the surface-treated inorganic fine powder (B), organic fillers, dispersing agent (C), In particular, the dispersant (C) is used for 100 parts by weight of the resin composition blended at a ratio of 20 to 80% by weight of the thermoplastic resin (A), 80 to 20% by weight of the inorganic fine powder (B) and 0 to 50% by weight of the organic filler. ) It is preferable to contain 0.01-100 weight part. The inorganic fine powder is preferably obtained by hydrophilizing the surface with a surface treatment agent (D).

  The thermoplastic resin (A) contained in the base film is preferably a crystalline polyolefin resin, and the dispersant (C) is an acid-modified polyolefin (preferably an acid modification rate of 0.01 to 20%) and / or silanol modification. The surface treatment agent (D) is preferably an inorganic fine powder treated with a water-soluble cationic polymer and / or a water-soluble anionic surfactant, and the water-soluble cationic polymer is a diallylamine salt and / or alkyl. It is preferable to use one having a diallylamine salt and a nonionic hydrophilic vinyl monomer as constituent units.

The water-based heat-sealable resin coat layer (E) is preferably a layer provided by a water-based dispersion, and the average particle diameter is preferably larger than the average opening diameter of the substrate film surface.
Further, when the drying after the heat-sealable resin is applied is completed, the coating film surface of the coat layer is preferably formed in the form of dispersion particles, and the phase transition temperature of the heat-sealable resin is 50 to 140. It is preferable that it is ° C. Furthermore, the application of the water-based heat-sealable resin coating agent may be performed either in-line and / or outline (or both).

The base film provided with the water-based heat-sealable resin coating layer (E) of the present invention may have a structure laminated on other resin films or other materials as long as the above conditions are satisfied. In particular, a laminated structure in which the base film on which the water-based heat-sealable resin coat layer (E) is provided is laminated with another resin film so as to be the outermost layer. Accordingly, the stretched resin film provided with the water-based heat-sealable resin coat layer (E) of the present invention as the outermost layer may have either a single-layer structure or a multilayer structure, and the water-based heat-sealable resin coat Those that are decorated by printing and / or printing on the opposite side of the layer (E), and those whose water-based heat-sealable resin coating layer (E) surface is decorated by printing and / or printing, also satisfy the above conditions. As long as it is included in the scope of the present invention.
Moreover, the label for in-mold shaping | molding using the said resin stretched film and the in-mold shaping | molding container by which this label was stuck are also included. The in-mold molded container is preferably one produced by differential pressure molding, hollow molding, injection molding, foam molding, stretch blow molding or compression molding, and also high density polyethylene, low density polyethylene, polypropylene, polyester, Those made of a material selected from the group consisting of polystyrene, polyvinyl chloride and polycarbonate are preferred.

  The stretched resin film of the present invention has a base film excellent in liquid absorbability and a water-based heat-sealable resin coat layer, and exhibits excellent in-mold label suitability. The stretched resin film of the present invention can be produced with a coating amount smaller than that of the prior art, and can be efficiently produced because there is no need for surface processing such as embossing for escaping air that has been conventionally performed. In addition, the heat-sealable resin coating layer constituting the stretched resin film of the present invention can be composed of a wide range of materials, and restrictions on coating and processing equipment are greatly relaxed compared to the conventional one. ing.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, the stretched resin film provided with the water-based heat-sealable resin coat layer (E) of the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Thermoplastic resin (A)]
The base film provided with the water-based heat-sealable resin coating layer (E) of the present invention contains a thermoplastic resin. Examples of the thermoplastic resin (A) used for the base film include crystalline propylene resins, crystalline ethylene resins such as high density polyethylene, medium density polyethylene and low density polyethylene, and polymethyl-1-penteneethylene-cyclic olefin copolymer. Crystalline polyolefin resins such as polymers, polyamide resins such as nylon-6, nylon-6,6, nylon-6,10, nylon-6,12, polyethylene terephthalate and copolymers thereof, polyethylene naphthalate, fat And thermoplastic polyester resins such as aromatic polyesters, and thermoplastic resins such as polycarbonate, atactic polystyrene, syndiotactic polystyrene, and polyphenylene sulfide. These may be used in combination of two or more.

Among these, from the viewpoint of chemical resistance and production cost, it is preferable to use a crystalline polyolefin resin, and it is more preferable to use a crystalline propylene resin.
As the crystalline propylene-based resin, it is preferable to use an isotactic polymer or a syndiotactic polymer obtained by homopolymerizing propylene. Copolymers mainly composed of propylene having various stereoregularities obtained by copolymerizing propylene with α-olefins such as ethylene, 1-butene, 1-hexene, 1-heptene and 4-methyl-1-pentene. Polymers can also be used. The copolymer may be a binary system or a ternary or higher multi-element system, and may be a random copolymer or a block copolymer.
Content of the thermoplastic resin (A) in a base film is 20 to 80 weight% normally, Preferably it is 25 to 75 weight%.

[Inorganic fine powder (B) and organic filler]
As inorganic fine powder (B) that can be used for the base film constituting the stretched resin film of the present invention, heavy calcium carbonate, light calcium carbonate, calcined clay, talc, titanium oxide, barium sulfate, zinc oxide, oxidation Examples thereof include inorganic fine powders such as magnesium, diatomaceous earth, and silicon oxide, composite inorganic fine powders having an aluminum oxide or hydroxide around the core of the inorganic fine powder, and hollow glass beads. Of these, use of heavy calcium carbonate, calcined clay, and diatomaceous earth is preferred because it is inexpensive and many pores are formed during stretching.
20-80 weight% is preferable and, as for content of the inorganic fine powder (B) in a base film, 25-75 weight% is more preferable. When the content of the inorganic fine powder (B) exceeds 80% by weight, stretching tends to be difficult. If it is less than 20% by weight, the desired surface area ratio cannot be obtained, and the liquid absorption coefficient tends to be insufficiently improved.

The organic filler that can be used for the base film constituting the stretched resin film of the present invention has a higher melting point or glass transition point than the above thermoplastic resin (A) for the purpose of pore formation. It is preferable to select from compatible resins. Specific examples include polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, acrylic acid ester or methacrylic acid ester polymer or copolymer, melamine resin, polyethylene sulfite, polyimide, polyethyl ether ketone, Examples thereof include polyphenylene sulfide, a homopolymer of cyclic olefin, and a copolymer (COC) of cyclic olefin and ethylene. When the crystalline polyolefin resin is used as the thermoplastic resin (A), in particular, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, cyclic olefin homopolymer, and cyclic olefin and ethylene. It is preferable to select from a copolymer (COC) such as
0-50 weight% is preferable and, as for content of the organic filler in a base film, 0-40 weight% is more preferable.

  The average particle size of the inorganic fine powder used in the present invention or the average dispersed particle size of the organic filler is preferably in the range of 0.1 to 20 μm, more preferably 0.5 to 15 μm. Considering the ease of mixing with the thermoplastic resin (A), it is preferable to use a material having a thickness of 0.1 μm or more. When the particle size is less than 0.1 μm, it is difficult to form pores by stretching, and there is a tendency that a stretched film having a desired surface cannot be obtained. On the other hand, when the average particle diameter exceeds 20 μm, the stretchability tends to decrease and the number of stretch breaks and perforations during molding tends to increase.

The average particle size of the inorganic fine powder used in the present invention is, for example, a particle size (cumulative) corresponding to 50% by a particle measuring device, for example, a laser diffraction particle measuring device (manufactured by Nikkiso Co., Ltd., trade name: Microtrac). (50% particle diameter) can be measured.
The particle diameter of the organic filler dispersed in the thermoplastic resin by melt kneading and dispersion can be obtained as an average value of the particle diameter by measuring at least 10 particles by electron microscope observation of the cross section of the stretched resin film. .

  One kind of inorganic fine powder or organic filler used in the present invention may be selected from the above and used alone, or two or more kinds may be selected and used in combination. When using in combination of 2 or more types, the combination of an inorganic fine powder and an organic filler may be sufficient.

[Dispersant (C)]
A dispersant (C) can be preferably used for the base film. Examples of the dispersant (C) used for the base film include acid-modified polyolefin and silanol-modified polyolefin. Among these, it is preferable to use acid-modified polyolefin. The acid-modified polyolefin includes a hydroxyl-free polyolefin obtained by random copolymerization or graft copolymerization of maleic anhydride, or a carboxylic acid group-containing polyolefin obtained by random copolymerization or graft copolymerization of an unsaturated carboxylic acid such as methacrylic acid or acrylic acid. And epoxy group-containing polyolefin obtained by random copolymerization or graft copolymerization of glycidyl methacrylate. Specific examples include maleic anhydride modified polypropylene, maleic anhydride modified polyethylene, acrylic acid modified polypropylene, ethylene / methacrylic acid random copolymer, ethylene / glycidyl methacrylate random copolymer, ethylene / glycidyl methacrylate graft copolymer, glycidyl. Examples include methacrylate-modified polypropylene, among which maleic anhydride-modified polypropylene and maleic anhydride-modified polyethylene are preferable.

  Specific examples of maleic anhydride-modified polypropylene and maleic anhydride-modified polyethylene include Mitsubishi Chemical's Modic AP “P513V” (trade name), Modic AP “M513” (trade name), Sanyo Chemical Industries Ltd. Yumex 1001, 1010 (trade name), Yumex 2000 (trade name), and HPR “VR101” (trade name) of Mitsui DuPont Chemical Co., Ltd. may be mentioned.

The acid modification rate of the acid-modified polyolefin is preferably 0.01 to 20%, more preferably 0.05 to 15%.
If the acid modification rate is less than 0.01%, the dispersion effect of the surface-treated inorganic fine powder (B) in the thermoplastic resin (A) tends to be insufficient. The softening point tends to be too low, making it difficult to compound with a thermoplastic resin.

The content of the dispersant (C) in the base film is usually 0.01 to 100 weights with respect to 100 parts by weight of the resin composition containing the thermoplastic resin (A), the inorganic fine powder (B), and the organic filler. Parts, preferably 0.05 to 90 parts by weight, more preferably 0.1 to 80 parts by weight.
When the content of the dispersant (C) is less than 0.01 parts by weight, the surface-treated inorganic fine powder is not sufficiently dispersed, so that a desired surface opening ratio cannot be obtained and the improvement of the liquid absorption coefficient is insufficient. Tend. On the other hand, when it exceeds 100 parts by weight, the stretchability is greatly lowered, and there is a tendency that the stretch break during molding is increased.

[Surface treatment agent (D)]
In this invention, the inorganic fine powder (B) surface-treated with the surface treating agent (D ) is used . It is preferable that the surface treating agent (D) used for the inorganic fine powder (B) hydrophilizes the surface of the inorganic fine powder (B). As the surface treatment agent (D), a water-soluble cationic copolymer which is a copolymer of a monomer (d1) selected from diallylamine salts or alkyldiallylamine salts and a nonionic hydrophilic vinyl monomer (d2), or a water-soluble anionic interface An activator is preferred. In the case of a water-soluble cationic copolymer, the anion forming the “salt” is selected from the group consisting of chloride ion, bromide ion, sulfate ion, nitrate ion, methyl sulfate ion, ethyl sulfate ion and methanesulfonate ion. It is preferable.

  Specific examples of (d1) include diallylamine salts, alkyldiallylamine salts and dialkyldiallylamine salts having 1 to 4 carbon atoms, that is, methyldiallylamine salts, ethyldiallylamine salts, dimethyldiallylamine salts, methacryloyloxyethyltrimethylammonium, acryloyloxyethyl. Trichloroammonium, methacryloyloxyethyldimethylethylammonium or acryloyloxyethyldimethylethylammonium chloride, bromide, methosulphate or ethosulphate, N, N-dimethylaminoethyl methacrylate or N, N-dimethylaminoethyl acrylate with epichlorohydrin , Epoxy compounds such as glycidol, glycidyl trimethyl ammonium chloride and alkyl They include quaternary ammonium salts obtained by. Particularly preferred among these are diallylamine salts, methyldiallylamine salts and dimethyldiallylamine salts.

  Specific examples of (d2) include acrylamide, methacrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxy (meth) acrylate, 3 -Hydroxypropyl (meth) acrylate, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester. Among these, acrylamide and methacrylamide are preferable.

  The copolymerization ratio of (d1) and (d2) can be arbitrarily set, but (d1) is preferably 10 to 99 mol%, more preferably 50 to 97 mol%, still more preferably 65 to 95 mol%. (D2) is preferably 90 to 1 mol%, more preferably 50 to 3 mol%, still more preferably 35 to 5 mol%.

  The surface treating agent (D) obtained from (d1) and (d2) uses an initiator such as ammonium persulfate or 2,2-azobis (2-amidinopropane) dihydrochloride in an aqueous medium. For 40 to 100 ° C. (for example, 50 to 80 ° C.) for 2 to 24 hours. The polymer can be produced by the methods described in JP-A-5-263010, JP-A-7-300568 and the like, and can be used to achieve the object of the present invention. Also, some of the methods described in JP-A-57-48340 and JP-A-63-235377 can be used. Of these, preferred are diallylamine or diallyldimethylamine hydrochloride, sulfate, methacrylamide and acrylamide copolymers.

  The molecular weight of the polymer is usually 0.05 to 3, preferably 0.1 to 0.7, particularly preferably 0.1 in terms of the intrinsic viscosity at 25 ° C. in a 1 mol / L sodium chloride aqueous solution. It is in the range of ~ 0.45. Moreover, when it represents with the weight average molecular weight measured by gel permeation chromatography, it is about 5,000-950,000 normally, Preferably it is 10,000-500,000, More preferably, it is 10,000-80,000. It is a range.

The surface treatment agent (D) made of a water-soluble anionic surfactant used for the treatment of the inorganic fine powder (B) has an anionic functional group in the molecule.
Specific examples thereof include a sulfonate (d3) having a hydrocarbon group having 4 to 40 carbon atoms, a phosphate ester salt having a hydrocarbon group having 4 to 40 carbon atoms, and a range having 4 to 40 carbon atoms. Examples of the monohydric or monoester salts of higher alcohols (d4), alkylbetaines having 4 to 30 carbon atoms, alkylsulfobetaines (d5), etc. Is appropriately selected. The “salt” in (d3) to (d4) is a lithium salt, a sodium salt, a potassium salt, a calcium salt, a magnesium salt, a 1-4 quaternary ammonium salt, or a 1-4 phosphonium salt, and is preferably a salt. Lithium salt, sodium salt, potassium salt, quaternary ammonium salt, more preferably sodium salt or potassium salt.

  The sulfonate having a hydrocarbon group having 4 to 40 carbon atoms in (d3) is a hydrocarbon group having a linear or branched or cyclic structure having 4 to 40 carbon atoms, preferably 8 to 20 carbon atoms. Sulfonates and sulfoalkanecarboxylates having an alkylbenzene sulfonate, naphthalene sulfonate, 4 to 30 carbon atoms, preferably 8 carbon atoms having 4 to 40 carbon atoms, preferably 8 to 20 carbon atoms. Alkylnaphthalene sulfonate having a linear or branched or cyclic structure in the range of -20, diphenyl ether or biphenyl sulfone having an alkyl group having a linear or branched structure of 1 to 30 carbon atoms, preferably in the range of 8 to 20 Acid salts; salts of alkyl sulfates having 1 to 30 carbon atoms, preferably in the range of 8 to 20; salts of sulfoalkanecarboxylic acid esters; carbon 8-30, preferably like sulfonates of alkylene oxide adducts of the alkyl alcohol in the range of 10 to 20 carbon atoms.

  Specific examples thereof include alkane sulfonates and aromatic sulfonates such as octane sulfonate, dodecane sulfonate, hexadecane sulfonate, octadecane sulfonate, 1- or 2-dodecylbenzene sulfonate, 1 -Or 2-hexadecylbenzenesulfonate, 1- or 2-octadecylbenzenesulfonate, various isomers of dodecylnaphthalenesulfonate, salts of β-naphthalenesulfonate formalin condensate, octylbiphenylsulfonate Various isomers, dodecyl diphenyl ether sulfonate, dodecyl lignin sulfonate; alkyl sulfate ester, ie dodecyl sulfate, hexadecyl sulfate; sulfoalkane carboxylate, ie dialkyl ester of sulfosuccinic acid, Group having a straight chain or branched or cyclic structure having 1 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more specifically, a salt of di (2-ethylhexyl) sulfosuccinate, N-methyl-N -(2-sulfoethyl) alkylamide salts (wherein the alkyl group has 1 to 30 carbon atoms, preferably 12 to 18), for example, an amide compound derived from N-methyltaurine and oleic acid, preferably 1 to 30 carbon atoms, preferably 10-18 carboxylic acid 2-sulfoethyl ester salt, lauryl sulfate triethanolamine, ammonium lauryl sulfate, polyoxyethylene lauryl sulfate, polyoxyethylene cetyl sulfate; carbon number 8-30, preferably in the range of 10-20 Alkyl Alcohol Alkylene Oxide Adduct Sulfonate, ie Lauryl Alcohol Ethylene Oxide Examples thereof include a sulfate ester salt of an adduct, a sulfate ester salt of an ethylene oxide adduct of cetyl alcohol, and a sulfate ester salt of an ethylene oxide adduct of stearyl alcohol.

  Specific examples of phosphoric acid mono-, diester salts, or phosphoric acid triesters having a hydrocarbon group having a linear or branched or cyclic structure having 4 to 40 carbon atoms, preferably 8 to 20 carbon atoms in (d4) Is disodium or dipotassium salt of dodecyl phosphate, disodium salt of hexadecyl phosphate, disodium or dipotassium salt of dododecyl phosphate, sodium or potassium salt of dihexadecyl phosphate, ethylene oxide adduct of dodecyl alcohol And phosphoric acid triesters.

  Specific examples of alkylbetaines and alkylsulfobetaines having a hydrocarbon group of 4 to 30 carbon atoms, preferably 10 to 20 carbon atoms of (d5) include lauryl dimethyl betaine, stearyl dimethyl betaine, dodecyldimethyl (3-sulfopropylene). ) Ammonium inner salt, cetyldimethyl (3-sulfopropyl) ammonium inner salt, stearyldimethyl (3-sulfopropyl) ammonium inner salt, 2-octyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, 2-lauryl -N-carboxymethyl-N-hydroxyethyl imidazolinium betaine etc. are mentioned.

  Among these, Preferably, it is a sulfonate (d3) having a hydrocarbon group having 4 to 40 carbon atoms, more preferably an alkanesulfonate having 10 to 20 carbon atoms, or 10 to 20 carbon atoms. Selected from the group consisting of an aromatic sulfonate having an alkyl group in the range of 1 and a sulfate ester salt of an alkylene oxide adduct of an alkyl alcohol having an alkyl group having a carbon number in the range of 10 to 20.

[Water-based heat-sealable resin coating layer (E)]
The water-based heat-sealable resin coating layer (E) in the present invention is formed by, for example, in-mold molding in which a label is attached in advance in a mold at the time of pressure molding or injection molding of a thermoplastic resin, and the label is attached simultaneously with the molding. It is useful as a coating layer that melts instantly with heat due to contact with the molten resin in the mold and uniformly adheres to the resin container simultaneously with molding. In this case, a water-based heat-sealable resin suitable for the in-mold molding label can be appropriately selected and used. Moreover, it is also useful for a coating layer to be bonded to other film materials using various heat sealing machines, and in this case, an aqueous heat-sealable resin can be appropriately selected from the surface properties of the film to be bonded.
The resin used for the water-based heat-sealable resin coating layer (E) is preferably a resin dispersion having heat-sealability suitable for in-mold molding or heat sealing. Examples of the dispersion of the resin having heat sealability include those obtained by emulsion polymerization, those obtained by suspension polymerization, and those that are mechanically pulverized by an extruder or the like and dispersed in an aqueous solvent.

Examples of the heat-sealable resin used in the water-based heat-sealable resin coat layer (E) of the present invention include acrylic polymers, vinyl acetate polymers, styrene polymers, vinyl chloride polymers, vinylidene chloride heavy polymers. Dispersions such as coalescence, polyethylene, polyurethane, polyester, epoxy resin, petroleum resin, rosin ester, silicone resin, alkyd resin, polybutadiene, butadiene copolymer, polybutene, butyl rubber, polypropylene, polychloroprene, polyisoprene can be used.
Among these, acrylic polymers, vinyl acetate polymers, and styrene polymers are preferable. Among them, ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, ethylene / acrylic acid ester copolymers, Aqueous dispersions of acrylic ester polymers, ethylene / vinyl acetate copolymers, and styrene / butadiene copolymers are preferred.

Dry coating amount of the heat sealable resin is appropriately selected according to the liquid absorption coefficient of the base film to be used is usually preferably ^{0.05~30g / m 2, 0.1~20g / m} 2 Gayori 0.2 to 10 g / m ² is more preferable.

When the dry coating amount is less than 0.05 g / m ^2, there is a tendency that sufficient adhesive strength with a container or another film cannot be exhibited when in-mold molding or heat sealing is performed. When the dry coating amount exceeds 30 g / m ² , the adhesive strength is sufficient. For example, there is a phenomenon (blistering) in which air enters between the in-mold molding label and the container and the label partially expands. It tends to occur easily.
Further, when the coating amount increases, there is a problem that coating cannot be completed by one coating, and multiple coatings are required, resulting in an increase in production cost.

The average particle diameter of the heat-sealable resin dispersion is preferably larger than the average opening diameter of the substrate film surface. Further, it is desirable that the heat-sealable resin is scattered on the surface of the base film in the form of particles after drying after coating. For this purpose, it is necessary to perform drying at a temperature equal to or lower than the phase transition temperature of the heat-sealable resin (the temperature at which the heat-sealable resin transitions from the solid phase to the liquid phase, also referred to as the film forming temperature). The phase transition temperature of the heat-sealable resin is preferably in the range of 50 to 140 ° C., more preferably in the range of 55 to 130 ° C. in view of in-mold molding suitability. When dried at a temperature exceeding 140 ° C, the particle form does not remain and the substrate film surface is covered in a smooth state, so that blistering occurs during in-mold molding, and blocking occurs during printing or label processing. There is a tendency that problems such as doing are easy to occur. Moreover, when the phase transition temperature of the heat seal layer is less than 50 ° C., the heat seal layer tends to be sticky or blocked during label storage.
Further, the case where the heat-sealable resin after coating and drying covers the surface of the base film at 30% or more, preferably 40 to 90%, more preferably 50 to 80% is suitable for in-mold molding.
In the case of less than 30%, there is a tendency that the adhesion with the molding container is lowered during in-mold molding.

  Specific examples of the water-based heat-sealable resin coating layer (E) used for in-mold molding labels include, for example, an ethylene / methacrylic acid copolymer dispersion having an average particle diameter of 1.2 μm and a phase transition temperature of 90 ° C. Is mentioned.

In the dispersion used for the water-based heat-sealable resin coating layer (E), various binder resins for improving the adhesion to the base film, and an anti-blocking agent for preventing blocking when processed into a label, In addition, it is preferable to add a slip agent, an antistatic agent or the like for improving the paper supply / discharge suitability during printing.
Furthermore, if necessary, a dispersant, a thickener, an antifoaming agent, an antiseptic, an ultraviolet absorber, an ultraviolet stabilizer, an antioxidant, a surfactant, an aqueous dye, a color pigment, and the like can be appropriately added. .

[Surface treatment method of inorganic fine powder]
In the present invention, it is preferable to perform surface treatment of the inorganic fine powder (B) using at least one kind of surface treatment agent (D). As the surface treatment method, various known methods can be applied and are not particularly limited.
The mixing device and the temperature and time during mixing are also appropriately selected according to the properties and physical properties of the surface treatment agent component to be used. The L / D (shaft length / shaft diameter) of various mixers used, the shape of the stirring blade, shear rate, specific energy, residence time, treatment time, treatment temperature, etc. are also appropriately determined according to the properties of the components used. Selectable.

  As an example of the surface treatment method of the inorganic fine powder (B), in the case of calcium carbonate produced by wet pulverization, a necessary amount of the surface treatment agent (D) with respect to 100 parts by weight of calcium carbonate particles having a particle size of 10 to 50 μm. ) In the presence of an aqueous medium to obtain a desired particle size. Specifically, water is added to calcium carbonate so that the weight ratio of calcium carbonate / aqueous medium (specifically water) is in the range of 70/30 to 30/70, preferably 60/40 to 40/60. The surface treatment agent (D) is added to 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 parts by weight of calcium carbonate, and wet pulverized by a conventional method. Furthermore, an aqueous medium in which a surface treatment agent having an amount in the above range is dissolved in advance may be prepared, the aqueous medium may be mixed with calcium carbonate, and wet pulverized by a conventional method. The wet pulverization may be a batch type or a continuous type, and it is preferable to use a mill using a pulverizer such as a sand mill, an attritor, or a ball mill. By wet pulverization in this way, calcium carbonate having an average particle size of 0.1 to 20 μm, preferably 0.5 to 15 μm is obtained.

  Next, the wet pulverized product is dried, but a classification step can be provided before drying to remove coarse powder such as 350 mesh-on. Drying can be performed by a known method such as hot air drying, but is preferably performed by medium fluidized drying. In the medium fluidized drying, a slurry substance is supplied into a medium particle group (fluidized bed) in a fluidized state by hot air (80 to 150 ° C.) in a drying tower, and the supplied slurry substance actively flows. In this method, various substances are dried by being dispersed in fluidized drying while adhering in the form of a film to the surface of the formed medium particles and receiving a drying action by hot air. Such medium fluidized drying can be easily performed using, for example, a medium fluidized drying apparatus “Media Slurry Dryer” manufactured by Nara Machinery Co., Ltd. This medium fluidized drying is preferable because drying and crushing of aggregated particles (removal of primary particles) are performed simultaneously. By this method, calcium carbonate with a very small amount of coarse powder can be obtained. However, it is also effective to perform pulverization and classification of the particles by a desired method after the fluidized drying of the medium. On the other hand, when the wet pulverized product is dried by ordinary hot air drying instead of medium fluidized drying, the obtained cake is preferably further pulverized and classified by a desired method. Since the wet cake of the wet pulverized product obtained by this method is easily crushed and calcium carbonate fine particles can be easily obtained, there is no need to bother the step of pulverizing the dry cake.

The inorganic fine powder (B) thus obtained can be further treated with another surface treatment agent.
Although the usage-amount of a surface treating agent (D) changes with uses of the resin stretched film which provided the water-system heat-sealable resin coat layer (E) of this invention, it is 0.01 ~ with respect to 100 weight part of inorganic fine powder normally. It is 10 parts by weight, preferably 0.04 to 5 parts by weight, more preferably 0.07 to 2 parts by weight.
If the amount of the surface treatment agent (D) used is less than 0.01 parts by weight, a sufficient surface treatment effect tends not to be obtained, and if it exceeds 10 parts by weight, the effect of the surface treatment agent tends to reach its peak.

[Quantity ratio of components]
The preferred amount ratio range of the components constituting the base film on which the water-based heat-sealable resin coat layer (E) of the present invention is provided is 20 to 80% by weight of the thermoplastic resin (A), the surface-treated inorganic fine powder (B ) A resin composition comprising 80 to 20% by weight and 0 to 50% by weight of an organic filler, and the dispersant (C) is added to the thermoplastic resin (A), the inorganic fine powder (B) and / or the organic filler in a total of 100%. It is a composition containing 0.01-100 weight part with respect to a part. At this time, if the content of the inorganic fine powder (B) and / or the organic filler exceeds 80% by weight, it tends to be difficult to obtain a film having a uniform film thickness, and the thermoplastic resin (A) is 80%. If the weight percentage is exceeded, a substrate film having a desired liquid absorption coefficient (10 ml / m ² · (ms) ^1/2 or more) and a surface opening ratio (7% or more) cannot be obtained. Water-based heat-sealable resin coating layer (E) having excellent adhesion to the substrate film surface when particles in the dispersion are less likely to enter the opening and in-mold molding is applied. ) Tends not to be obtained. Moreover, you may mix | blend a thermal stabilizer, a ultraviolet stabilizer, antioxidant, an antiblocking agent, a nucleating agent, a lubricant, a coloring agent, etc. in each structural component as needed. These are preferably blended in a proportion of 3% by weight or less.

[Production of stretched resin film provided with water-based heat-sealable resin coating layer (E)]
The stretched resin film provided with the water-based heat-sealable resin coat layer (E) of the present invention can be produced by combining various methods known to those skilled in the art. A stretched resin film produced by any method is included within the scope of the present invention as long as it satisfies the conditions described in the present invention.

The stretched resin film provided with the water-based heat-sealable resin coating layer (E) of the present invention comprises a thermoplastic resin (A), an inorganic fine powder (B) hydrophilized with a surface treatment agent (D), an organic filler, The dispersant (C) is mixed at a predetermined ratio, and formed into a film by a method such as extrusion, and then at a temperature lower than the melting point of the thermoplastic resin (A), preferably 3 to 60 ° C., uniaxially or biaxially. By stretching in the direction, a liquid-absorbing substrate film having fine voids (voids) uniformly on the surface and inside of the film is obtained, and the obtained film is produced (inline) and / or outside the process. It was coated so as to 0.05~30g / m ² on a solid basis by a known method a dispersion such as a (outline) such as ethylene-methacrylic acid copolymer, dispersion particles To be present on the surface as a child form, and dried in the following phase transition temperature, it is possible to obtain excellent water heat sealable resin coat layer provided with the stretched resin film (E).

A stretched resin film in which a water-based heat-sealable resin coating layer is provided on the surface obtained by the above method on a base film having a liquid absorption coefficient of 5 ml / m ² · (ms) ^1/2 or more according to the present invention. Is superior in-mold molding with a smaller coating amount than a label used for in-mold molding having a heat-sealable resin layer provided by, for example, a known outline coating method or in-line coextrusion method on polypropylene film Since suitability is obtained, an inexpensive label for in-mold molding having excellent productivity and label quality, and a product container can be obtained.

The liquid absorption coefficient of the liquid-absorbing base film produced by the above method is 5 ml / (m ² · ms ^1/2 ) or more, preferably 10 ml / (m ² · ms ^1/2 ) or more, More preferably, it is 15-50 ml / (m < ² > * ms < ^1/2 >). When the liquid absorption coefficient is less than 5 ml / m ² · (ms) ^1/2 , the water absorption rate at the time of coating the aqueous coating agent is insufficient, and the viscosity increase of the coating liquid is small, and the desired coating amount and coating The surface morphology of the film cannot be obtained.
In the present specification, “liquid absorption coefficient” refers to JAPAN TAPPI No. It is measured by a BLISTOW water absorption test based on 51-87, and means a value obtained from the gradient obtained by obtaining a straight line from the water absorption curve at 20 milliseconds to 40 milliseconds from the water absorption start by the least square method. The liquid absorption coefficient can be measured by a specific procedure described in a test example described later.

  Further, the surface opening ratio (surface porosity) of the outermost layer of the base film is preferably 7% or more, and more preferably 10 to 30%. When the surface opening ratio is less than 7%, sufficient liquid absorbability tends to be not obtained. On the other hand, if it exceeds 30%, the strength of the substrate surface is lowered, and when it is molded in-mold and attached to a container, it easily peels off from the substrate surface layer and tends to cause a problem in practice.

  “Surface opening ratio” and “average opening diameter” in the present specification are in the observation region when the surface of the base film before providing the water-based heat-sealable resin coating layer (E) in the present invention is observed with an electron microscope. Shows the average value of the area ratio occupied by the holes and the short side length of the 20 holes in the observation region. Specifically, an arbitrary part of the base film sample is cut out and attached to an observation sample stage, and gold or gold-palladium is vapor-deposited on the observation surface to scan an electron microscope (for example, manufactured by Hitachi, Ltd.). It can be determined by observing surface vacancies at an arbitrary magnification (for example, magnification of 500 to 3000 times) that is easy to observe using a scanning microscope S-2400). Further, the observed area was photographed, and the holes were traced on the tracing film, and the image filled with the image was processed with an image analysis device (manufactured by Nireco Corporation: model Luzex IID). It can also be set as the aperture ratio of the base film surface. Moreover, the short side length of 20 holes opened on the surface is measured from the electron micrographs observed at the same time, and an average value thereof is obtained as an average opening diameter. In addition, the short side length of a void | hole means the length of the direction shown in FIG.

The stretched resin film of the present invention has a water-based heat-sealable resin coat layer (E) as the outermost layer, and is usually printed and / or printed on the opposite surface by various printing methods and / or printing methods. Depending on the application, it may be used by being laminated on a thermoplastic resin film, laminated paper, pulp paper, nonwoven fabric, cloth or the like. About a laminated film structure, you may manufacture by extending | stretching after each layer is extended | stretched separately, and may extend | stretch and manufacture collectively after laminating | stacking. Moreover, you may print on the surface of these laminated films, and the back surface, and may use them. These methods can be combined as appropriate.
Furthermore, the stretched resin film of the present invention can be used by printing and / or printing on the surface provided with the water-based heat-sealable resin coat layer (E). By printing and / or printing on the surface on which the water-based heat-sealable resin coating layer (E) is provided, various surfaces can be attached to highly transparent containers such as PET bottles, PP bottles, and LD-PE bottles. It is possible to increase the added value of the container by adding simple information or improving decorativeness. A known method can be used for such printing and / or printing, for example, offset printing, letterpress printing, gravure printing, flexographic printing, screen printing, electrophotographic printing, ink jet printing, fusion heat transfer printing, sublimation heat transfer printing, and the like. Can be mentioned. Even if the stretched resin film of the present invention is printed on the water-based heat-sealable resin coating layer (E), it has excellent blistering properties and label adhesion, and therefore heats through a transparent hollow container with a label attached. Printing performed on the surface of the sealing resin coat layer (E) can be clearly recognized.

The stretched resin film provided with the water-based heat-sealable resin coat layer (E) of the present invention is preferably stretched in at least a uniaxial direction, and may be stretched in a biaxial direction.
For example, a crystalline polyolefin resin film containing 0 to 40% by weight, preferably 3 to 33% by weight of an inorganic fine powder is oriented in a uniaxial direction obtained by stretching in one direction at a temperature lower than the melting point of the resin. A resin composition comprising a film as a base material layer and comprising 20 to 80% by weight of a thermoplastic resin (A) and 80 to 20% by weight of a surface-treated inorganic fine powder (B) on at least one side, and 0 to 50% by weight of an organic filler Resin composition molten resin containing 0.01 to 100 parts by weight of a total of 100 parts by weight of the thermoplastic resin (A), inorganic fine powder (B), and organic filler as a dispersant (C) Is laminated as the outermost layer, and then the laminated film is stretched in a direction perpendicular to the stretching direction, whereby the outermost layer is oriented in the uniaxial direction and the base material layer is oriented in the biaxial direction. F Lum is obtained.
Furthermore, the water-based heat-sealable resin coat layer (E) is provided on the surface of the outermost layer of the base film to obtain the stretched resin film of the present invention.
A preferable production method includes a step of providing a heat-sealable resin coating layer (E) on the film surface obtained by laminating the base material layer and the outermost layer and then stretching them together. Compared with the case of separately stretching and laminating, it is simpler and the manufacturing cost is lower.

Various known methods can be used for stretching. The stretching is preferably performed at a temperature 5 ° C. or more lower than the melting point of the resin, and when two or more resins are used, it is preferably performed at a temperature 5 ° C. or more lower than the melting point of the resin occupying the maximum amount.
Specific methods of stretching include stretching between rolls utilizing the peripheral speed difference of the roll group, clip stretching using a tenter oven, and the like. Stretching between rolls is preferable because it is easy to obtain a film having any rigidity, opacity, smoothness, and glossiness by arbitrarily adjusting the stretching ratio. The draw ratio is not particularly limited, and is determined in consideration of the intended use of the stretched resin film of the present invention and the characteristics of the resin used. Usually, it is 2 to 11 times, and preferably stretched within a range of 3 to 10 times. Among these, the draw ratio is more preferably 4 to 7 times.
In the case of clip stretching using a tenter oven, stretching is preferably performed 4 to 11 times. As area magnification, it is 2-80 times normally, Preferably it is 3-60 times, More preferably, it is 4-50 times. If the area magnification is less than 2 times, a predetermined aperture ratio cannot be obtained on the surface of the stretched resin film, and sufficient water absorption cannot be obtained, and the water-based heat-sealable resin coat layer (E) having good adhesion to the container on the surface Tends to be difficult to provide. Moreover, when it exceeds 80 times, there exists a tendency for extending | stretching cut | disconnection and coarse perforation to increase.

  It is preferable to heat-treat the base film after stretching. The temperature of the heat treatment is preferably selected within the range of a temperature 30 ° C. higher than the stretching temperature from the stretching temperature. By performing the heat treatment, the thermal shrinkage rate in the stretching direction is reduced, and squeezing due to shrinkage at the time of product storage and heat and fusing sealing is reduced. The heat treatment is generally performed by a roll and a heat oven, but these may be combined. In these treatments, it is preferable to heat-treat the stretched film in a state where the stretched film is held under tension because a higher treatment effect can be obtained.

Further, after the heat treatment, the surface is preferably subjected to oxidation treatment such as corona discharge treatment or plasma treatment. When the water-based heat-sealable resin coating layer (E) is provided by the oxidation treatment, the surface wettability is further improved, the solvent absorption rate of the heat-sealable resin dispersion is improved, and the opening diameter of the base film surface Smaller particle size resins are desirable because they are faster and have the advantage of more penetration.
Furthermore, there is an advantage that the adhesiveness with the water-based heat sealable resin is improved.

  The total thickness of the stretched resin film provided with the water-based heat-sealable resin coat layer (E) is not particularly limited, but is preferably 40 to 400 μm, more preferably 50 to 350 μm, and still more preferably 60 to 300 μm. The thickness of the outermost layer of the base film in contact with the aqueous heat-sealable resin coating layer (E) is preferably 3 to 100 μm, preferably 5 to 80 μm in consideration of absorption of the aqueous solvent contained in the aqueous heat-sealable resin dispersion. Is more preferable. The thickness of the water-based heat-sealable resin coat layer (E) is preferably 0.05 to 40 μm, more preferably 0.1 to 30 μm, depending on the purpose of use.

  When the stretched resin film provided with the water-based heat-sealable resin coat layer (E) according to the present invention is used as a label for in-mold molding, various types of resin containers can be obtained by appropriately selecting the type of the water-based heat seal resin and the phase transition temperature. Can be used for For example, it can be used for containers made of high-density polyethylene, low-density polyethylene, polypropylene, polyester, polystyrene, polyvinyl chloride, polycarbonate, and the like, and is particularly suitable for high-density polyethylene, polypropylene, polyester, and polystyrene. These resin containers are manufactured by differential pressure molding, hollow molding, injection molding, foam molding, stretch blow molding, or compression molding. Among these, it is suitable for differential pressure molding, hollow molding, injection molding, and stretch blow molding. Moreover, it has the advantage that it can be widely used for special containers that were difficult to mold with conventional labels.

General methods such as blade method, rod method, wire bar method, slide hopper method, curtain method, air knife method, roll method, comma method, size press method, gravure method, reverse gravure method, etc. A typical coating method is used. Moreover, the method of coating combining these general coating methods suitably is also used.
The drying method after coating is performed by a known drying means, but in the drying process, it must be dried under conditions that do not exceed the phase transition temperature of the heat-sealable resin used.

  Hereinafter, the present invention will be described more specifically with reference to Preparation Examples, Production Examples, Examples, Comparative Examples, and Test Examples. The materials, amounts used, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the specific examples shown below.

(Preparation Example 1) Preparation of surface treatment agent (D) In a reactor equipped with a reflux condenser, a thermometer, a dropping funnel, a stirrer, and a gas introduction pipe, 500 parts by weight of diallylamine hydrochloride (60% strength by weight aqueous solution) Then, 13 parts by weight of acrylamide (40% strength by weight aqueous solution) and 40 parts by weight of water were added, and the system temperature was raised to 80 ° C. while flowing nitrogen gas. Under stirring, a polymerization funnel and 30 parts by weight of ammonium persulfate (25% strength by weight aqueous solution) were added dropwise over 4 hours using a dropping funnel. The reaction was continued for 1 hour after the completion of the dropwise addition to obtain a viscous light yellow liquid. 50 g of this was taken and poured into acetone in 500 ml, resulting in a white precipitate. The precipitate was filtered off and further washed twice with 100 ml of acetone, and then dried under vacuum to obtain a white solid polymer (water-soluble cationic copolymer). The weight average molecular weight calculated | required from GPC of the obtained polymer was 55,000.

(Preparation Example 2) Preparation of surface-treated heavy calcium carbonate Heavy calcium carbonate (average particle size 8 μm, dry pulverized product manufactured by Nippon Cement Co., Ltd.) 40% by weight and 60% by weight of water were thoroughly mixed to prepare a slurry. 0.06 part by weight of the surface treatment agent (D) produced in Example 1 per 100 parts by weight of heavy calcium carbonate was added, and a table-type attritor type medium stirring mill (glass beads with a diameter of 1.5 mm, filling rate of 170%, Wet grinding was performed using a peripheral speed of 10 m / sec.
Next, 50 parts of a mixture (2% by weight aqueous solution) of a sodium alkanesulfonate having 14 carbon atoms and a sodium alkanesulfonate having 16 carbon atoms were added and stirred. Next, the particles were classified through a 350 mesh screen, and the slurry that passed through the 350 mesh was dried with a medium fluidized dryer (MSD-200 manufactured by Nara Machinery Co., Ltd.). When the average particle diameter of the obtained calcium carbonate was measured by Microtrac (manufactured by Nikkiso Co., Ltd.), it was 1.5 μm.

(Production example)
According to the following procedures, the base film (manufacturing examples 1-9) which satisfy | fills the conditions of this invention and the base film (manufacturing examples 10-16) used for the comparative example were manufactured.
Table 1 shows details of the materials used. “MFR” in the table means melt flow rate. Table 2 lists the type and amount (% by weight) of materials used in the production of each base film, stretching conditions, thickness of each layer, and opacity. The material numbers listed in Table 2 correspond to the material numbers listed in Table 1. In addition, the dispersing agent addition amount of Table 2 is displayed by the weight part when the total addition amount of the materials 1 to 3 is 100 parts by weight.

In Production Examples 1 to 6, 9, 10, and 11, the compound [A] shown in Table 2 was melt kneaded with an extruder set at 250 ° C., extruded, and cooled to 70 ° C. with a cooling device. Thus, a single-layer unstretched sheet was obtained.
The unstretched sheet was heated to the stretching temperature (1) shown in Table 2, and then stretched 5 times between rolls in the longitudinal direction to obtain a longitudinally uniaxially stretched film. Next, the blend [B] shown in Table 2 was melt-kneaded with an extruder set at 250 ° C. and laminated on both sides of the longitudinally uniaxially stretched film. The laminate was heated to the stretching temperature (2) shown in Table 2 and stretched 8 times in the transverse direction using a tenter stretching machine, and heat-treated at a temperature 20 ° C. higher than the stretching temperature (2). A bilayer stretched / uniaxially stretched three-layer resin stretched film was obtained.

  In Production Example 7, the compound [A] and the compound [B] shown in Table 2 were melt-kneaded with three extruders each set at 250 ° C., and laminated with a feed block die. The sheet was extruded and cooled to 70 ° C. with a cooling device to obtain a three-layer unstretched sheet. After heating this unstretched sheet to the stretching temperature (1) described in Table 2, it was stretched 5 times between the rolls in the machine direction, then heated to the stretching temperature (2) and then used in the transverse direction 8 using a tenter stretching machine. The film was stretched twice and heat treated at a temperature 20 ° C. higher than the stretching temperature (2) to obtain a biaxially stretched / biaxially stretched / biaxially stretched three-layer resin stretched film.

  In Production Example 8, the compound [B] shown in Table 2 was melt-kneaded with an extruder set at 250 ° C., extruded, cooled to 70 ° C. with a cooling device, and a single-layer unstretched sheet was formed. Obtained. After heating this unstretched sheet to the stretching temperature (1) described in Table 2, it was stretched 5 times between rolls in the longitudinal direction, and heat-treated at a temperature 20 ° C. higher than the stretching temperature (1). A stretched resin film was obtained.

In Production Example 12, a uniaxially stretched / biaxially stretched / uniaxially stretched three-layer resin stretched film of Example 3 of JP-A-2001-181423 was used.
In Production Example 13, a monolayer stretched / biaxially stretched / uniaxially stretched three-layer resin stretched film of Example 3 of JP-A-2001-226507 was used.
In Production Example 14, the uniaxially stretched / biaxially stretched / uniaxially stretched three-layer resin stretched film of Example 3 of JP-A No. 2001-164017 was used.
In Production Example 15, a monolayer stretched / biaxially stretched / uniaxially stretched three-layer resin stretched film of Example 4 of JP-A No. 2001-151918 was used.
In Production Example 16, the uniaxially stretched / biaxially stretched / uniaxially stretched three-layer resin stretched film of Example 2 of JP-A-10-212367 was used.

The base film is subjected to a corona treatment of 40 w / m ² · min on both surfaces of the single-layer and three-layer stretched resin films obtained in Production Examples 1 to 16 using a discharge treatment machine (manufactured by Kasuga Denki Co., Ltd.). Got. Table 2 shows the results of measuring the opacity of each base film with a measuring device (manufactured by Suga Test Instruments Co., Ltd .: SM-5) in accordance with JIS P-8138.

(Examples 1-9, Comparative Examples 1-7)
A dispersion comprising a heat-sealable resin described in Table 3, an anti-blocking agent described in Table 3, and water are mixed so as to have a predetermined solid content concentration described in Table 4, and an aqueous coating agent. Was prepared. This water-based coating agent was applied to the front side of the base film of Production Examples 1 to 16 at a line speed of 20 m / min with a slot die coater, and dried in an oven with a length of 10 m set to the drying temperature described in Table 4. Thus, a film for in-mold molding label was obtained. The coating amount of the obtained film after drying was as shown in Table 4.

(Test example)
About the surface of each base film manufactured in the manufacture example, the dispersibility of the inorganic fine powder, the surface opening ratio, the surface opening diameter, and the liquid absorption coefficient were evaluated. Details of each test are as follows.

1) Dispersibility of inorganic fine powder The base film produced in Production Examples 1 to 16 was cut into a size of 500 mm in length and 500 mm in width, and reflected on the surface (the surface of the blend [B]) from an angle of 20 °. The inorganic fine powder aggregates (surface projections) of 0.1 mm or more were counted by applying light, the number per unit area was counted, and evaluation was performed in the following three stages.
○: Less than 3 pieces / m ² Δ: 3 pieces / m ² or more and less than 10 pieces / m ² ×: 10 pieces / m ² or more

2) Surface aperture ratio, aperture diameter An arbitrary part is cut off from the base film produced in Production Examples 1 to 16, and attached to an observation sample stage, and gold is deposited on the observation surface (the surface of the compound [B]). The surface was photographed at a magnification of 2000 using a scanning microscope (S-2400, manufactured by Hitachi, Ltd.). An image analysis device (manufactured by Nireco Co., Ltd .: Model Luzex IID) was subjected to image processing by tracing and filling the holes in the tracing film, and the surface opening ratio of the stretched resin film was measured.
Further, 20 open holes were arbitrarily selected from the surface photograph, the length of the shortest side passing through the center of the hole was determined, and the average value was defined as the surface opening diameter.

3) Liquid absorption coefficient The liquid absorption coefficient of the base film produced in Production Examples 1 to 16 was determined according to the BRISTOW method (JAPAN TAPPI No. 51-87). Co., Ltd .: BRISTOW tester type II). The liquid absorption coefficient was obtained from the slope of a straight line obtained by the least square method from the water absorption curve at 20 to 40 milliseconds after dropping of the measurement solution. The measurement solution used was a mixture of 2% by weight of stamping ink (red) (manufactured by Shachihata Co., Ltd.) as a coloring dye in 98% by weight of distilled water. The magnitude of the liquid absorption coefficient was evaluated in the following four stages.
Δ is problematic in practice, and × is not practical.
◎: 15 ml / (m ² · ms ^1/2 ) or more ○: 5 ml / (m ² · ms ^1/2 ) or more and less than 15 ml / (m ² · ms ^1/2 ) △: 1 ml / (m ² · ms ^{1) / 2} ) or more and less than 5 ml / (m ² · ms ^1/2 ) ×: less than 1 ml / (m ² · ms ^1/2 )

  About the base film provided with the heat-sealable resin coating layer obtained in Examples and Comparative Examples, the coating layer surface form and in-mold label suitability (label mounting property, blistering property, label adhesion property) were evaluated. . Details of the test for each evaluation are as follows.

4) Coat layer surface form 10 types of coat layer surface of the base film provided with the heat-sealable resin coat layers of Examples 1 to 9 and Comparative Examples 1 to 7 were scanned with a scanning microscope (Hitachi, Ltd., S- 2400) was observed at a magnification of 2000 times. Whether or not the used dispersion remained in the form of particles was observed, and evaluated and determined in the following three stages.
A: All are in particle form.
○: Some particles are fused, but there is no practical problem.
X: No particle form is seen at all, and the film is formed.

5) Test of in-mold label suitability A base film provided with the heat-sealable resin coating layers of Examples 1 to 9 and Comparative Examples 1 to 7 was punched out to a length of 70 mm and a width of 60 mm. As shown in FIG. 2, a mold in which the printing surface (1-a) opposite to the surface (1-b) coated with the heat-sealable resin is set to 25 ° C. of a hollow container manufacturing molding machine. The inner wall (2-a) of (2) was attached by vacuum suction from the vacuum vacuum suction hole (5) and fixed. Thereafter, high-density polyethylene (HDPE, manufactured by Nippon Polychem Co., Ltd .: trade name “HB-330”) heated and melted at 180 ° C. was hollow molded in a shot cycle of 12 seconds to obtain a hollow container with a label attached thereto.

  Similarly, a hollow container having a label attached thereto was obtained using high impact polystyrene (HIPS, manufactured by Dainippon Ink & Chemicals, Inc .: trade name “Dick Styrene IB-100”) heated and melted to 210 ° C. .

  Furthermore, as shown in FIG. 3, the printing surface (11-a) opposite to the surface (11-b) coated with the heat-sealable resin is a stretch blow molding machine (manufactured by Yoki Sangyo Co., Ltd .: “ "Product name PET-2W type") was attached and fixed by vacuum suction from the vacuum vacuum suction hole (14) so as to contact the inner wall (12-a) of the mold (12) set at 25 ° C. Thereafter, polyethylene terephthalate (PET, manufactured by Nihon Unipet Co., Ltd .: trade name “Unipet RT543”), which was previously molded into a small container-shaped preform (13) with an injection molding machine, was heated to 95 ° C. with an infrared heater. Then, it was stretched and hollow molded in a shot cycle of 30 seconds to obtain a hollow container with a label attached thereto.

  The label mounting property during the molding and the obtained label-attached hollow container were evaluated by the following methods.

5-1) Label mounting (insert) property The label mounting status in 100-shot hollow molding was evaluated and determined according to the following criteria.
○: All installed in the specified location without problems.
Δ: There is no drop of the label, but there is a shift in the designated label position, which is problematic in practical use.
×: The label was dropped or the label specified position was misaligned.

5-2) Blistering property The blister generation status of each of the 20 containers attached is determined according to the following criteria,
5 points: No blister generation 4 points: Blister generation is less than 10% of the label area 3 points: Blister generation is 10% or more and less than 20% of the label area 2 points: Blister generation is 20% or more of the label area 50 Less than% 1 point: Blister generation is 50% or more of the label area. The total score of 20 containers was evaluated (100 points maximum).
○: 100 points △: 80-99 points ×: 79 points or less

5-3) Label adhesion The label part of the container to which the label is attached is cut into four 15 mm widths, a part of the label edge is peeled off, and a tensile tester (Orientec Co., Ltd .: RTM type) is used to obtain 200 mm / The peel strength (g) was measured at a rate of minutes, and the average value was obtained and determined according to the following criteria.
○: 200 g or more Δ: 100 to less than 200 g ×: less than 100 g

6) Printability of heat-sealable resin-coated layer surface Inkjet printer printing and gravure printing were performed on the surface provided with the heat-sealable resin-coated layer of Example 1, Comparative Examples 1 and 7 under the following conditions, and a pattern for interior decoration was applied. After the production, punched labels were produced in a length of 70 mm and a width of 60 mm.
<Inkjet printer printing>
Printer: CANON BJF-850C (6 colors, dye ink)
Printed pattern: Japanese Standards Association SCID wine and tableware "A4"
Print setting: Plain paper mode, no color correction by the driver Environment: Windows (registered trademark) ME Pentium (registered trademark) 4 1.8 GHz,
RAM512MB Parallel I / F
Software used: Adobe Photoshop 5.0J
<Gravure printing>
Printing machine: DNK 10-color machine Printing pattern: Japanese Standards Association SCID Wine and tableware "A4"
Ink: manufactured by Dainichi Seika Kogyo Co., Ltd. CSUP (yellow, indigo and red)
Plate roll: 175 lines

  As shown in FIG. 2, the printing surface (1-a) opposite to the surface (1-b) coated with the heat-sealable resin subjected to inkjet printer printing and gravure printing is a molding machine for manufacturing a hollow container. The vacuum was reduced and sucked from the vacuum vacuum suction hole (5) so as to come into contact with the inner wall (2-a) of the mold (2) set at 25 ° C. Thereafter, low-density polyethylene (LDPE, manufactured by Nippon Polychem Co., Ltd .: trade name “ZE41”) melted by heating at 160 ° C. was hollow molded in a shot cycle of 12 seconds to obtain a hollow container with a label attached thereto.

  Furthermore, as shown in FIG. 3, the surface (11-a) opposite to the surface (11-b) coated with the heat-sealable resin subjected to inkjet printer printing and gravure printing is a stretch blow molding machine. (Yoki Sangyo Co., Ltd .: “trade name PET-2W type”) vacuum suction from the vacuum vacuum suction hole (15) so as to contact the inner wall (12-a) of the mold (12) set at 25 ° C. And fixed. Thereafter, polyethylene terephthalate (PET, manufactured by Nihon Unipet Co., Ltd .: trade name “Unipet RT543”), which was previously molded into a small container-shaped preform (13) with an injection molding machine, was heated to 95 ° C. with an infrared heater. Then, it was stretched and hollow molded in a shot cycle of 30 seconds to obtain a hollow container with a label attached thereto.

Blistering properties and label adhesion were evaluated by the above methods for the label-attached hollow containers obtained by these moldings. The in-mold label of Example 1 had good blistering properties and label adhesion even when either low-density polyethylene or polyethylene terephthalate was used as a hollow container.
Moreover, the printing state given to the heat-sealable resin coat layer (E) surface was visually observed through a transparent hollow container to which the label was attached, and evaluated and judged according to the following criteria.
○: Printing applied to the heat-sealable resin coat layer (E) surface was clearly observed.
X: Printing applied to the heat-sealable resin coat layer (E) surface was unclear.
The test results are shown in Tables 4 and 5.

  As is clear from the above results, the stretched resin film of the present invention produced by providing an aqueous heat-sealable resin coating layer on a base film having a good liquid absorption coefficient exhibits excellent in-mold label suitability (implementation) Examples 1-9). On the other hand, the stretched resin film outside the conditions of the present invention is inferior in suitability and lacks practicality (Comparative Examples 1 to 7).

  The stretched resin film of the present invention has a base film excellent in liquid absorbability and a water-based heat-sealable resin coat layer, and exhibits excellent in-mold label suitability. The stretched resin film of the present invention can be produced with a coating amount smaller than that of the prior art, and can be efficiently produced because there is no need for surface processing such as embossing for escaping air that has been conventionally performed. In addition, the heat-sealable resin coating layer constituting the stretched resin film of the present invention can be composed of a wide range of materials, and restrictions on coating and processing equipment are greatly relaxed compared to the conventional one. ing. Because of these characteristics, the stretched resin film of the present invention is extremely useful as an in-mold molding label for non-polyolefin resin containers such as polystyrene and polyester as well as polyolefin.

It is a figure explaining the short side length of a void | hole. It is sectional drawing of the molding machine used for the in-mold label suitability test for polyethylene or a polystyrene hollow container. It is sectional drawing of the molding machine used for the in-mold label suitability test for polyethylene terephthalate hollow containers.

Explanation of symbols

1-a: Label printing surface 1-b: Label bonding surface 2: Mold 2-a: Inner wall 3: Die 4: Barison 5: Suction hole 6: Air blowing nozzle 11-a: Label printing surface 11-b: Label Bonding surface 12: Mold 12-a: Inner wall 13: Preform 14: Suction hole 15: Stretched rod

Claims (23)

A stretched resin film in which a water-based heat-sealable resin coating layer (E) is provided on a base film having a liquid absorption coefficient of 5 ml / m ² · (ms) ^1/2 or more ,
Resin composition in which the base film is blended with 20 to 80% by weight of thermoplastic resin (A) and 80 to 20% by weight of inorganic fine powder (B) surface-treated with at least one surface treatment agent (D). Containing 100 to 100 parts by weight of the dispersant (C) 0.01 to 100 parts by weight, and
The stretched resin film , wherein the dispersant (C) is an acid-modified polyolefin, a silanol-modified polyolefin, or both . 2. The stretched resin film according to claim 1, wherein the substrate film has a surface opening ratio of 7% or more. Content of an organic filler is 0 weight%, The resin stretched film of Claim 1 or 2 characterized by the above-mentioned. 4. The stretched resin film according to claim 1, wherein the dispersant (C) is an acid-modified polyolefin . The stretched resin film according to any one of claims 1 to 4, wherein the thermoplastic resin (A) is a crystalline polyolefin-based resin. Stretched resin film according to any one of claims 1-5, characterized in that the dispersing agent (C) starved silanol-modified polyolefin. The acid-modified polyolefin has an acid modification rate of 0.01 to 20%, and the stretched resin film according to any one of claims 1 to 6 . The stretched resin film according to any one of claims 1 to 7, wherein the surface of the inorganic fine powder (B) is hydrophilized with the surface treatment agent (D). The stretched resin film according to any one of claims 1 to 8, wherein the surface treatment agent (D) is a water-soluble cationic copolymer and / or a water-soluble anionic surfactant. 10. The stretched resin film according to claim 9, wherein the water-soluble cationic copolymer comprises a diallylamine salt and / or an alkyldiallylamine salt and a nonionic hydrophilic vinyl monomer as constituent units. The stretched resin film according to any one of claims 1 to 10, wherein the base film is stretched in at least a uniaxial direction, and the area stretch ratio is 2 to 80 times. The resin stretched film which has a structure which laminated | stacked the other resin film so that the base film in any one of Claims 1-11 may become a layer which contact | connects a water-system heat sealable resin coat layer (E). The resin stretch according to any one of claims 1 to 12, wherein the water-based heat-sealable resin coating layer (E) is provided by applying and drying a coating liquid containing a water-based dispersion. the film. 14. The stretched resin film according to claim 13, wherein the average particle diameter of the dispersion is larger than the average opening diameter of the substrate film surface. 15. The stretched resin film according to claim 13 or 14, wherein the dispersion is coated on the surface in the form of particles. The stretched resin film according to any one of claims 1 to 15, wherein the phase transition temperature of the heat-sealable resin contained in the water-based heat-sealable resin coat layer (E) is 50 to 140 ° C. The stretched resin film according to any one of claims 1 to 16, wherein the water-based heat-sealable resin coat layer (E) is provided by in-line coating and / or outline coating. The stretched resin film according to claim 1, wherein the stretched resin film is decorated by printing and / or printing on the opposite surface of the water-based heat-sealable resin coating layer (E) of the stretched resin film. The stretched resin film according to claim 1, wherein the surface of the water-based heat-sealable resin coat layer (E) is decorated by printing and / or printing. An in-mold molding label using the stretched resin film according to claim 1. An in-mold molded container to which the label according to claim 20 is attached. The in-mold molded container according to claim 21, wherein the in-mold molded container is manufactured by differential pressure molding, hollow molding, injection molding, foam molding, stretch blow molding or compression molding. The in-mold molding container is made of a material selected from the group consisting of high-density polyethylene, low-density polyethylene, polypropylene, polyester, polystyrene, polyvinyl chloride, and polycarbonate. Molded container.

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