JP6316212B2 - Laminated film and packaging material - Google Patents

Description

  The present invention relates to a laminated film that enables heat resistance and good packaging suitability without bonding a stretched substrate having heat resistance.

  Conventionally, a packaging material is required to have high heat seal strength, pinhole resistance, low temperature impact resistance and the like from the viewpoint of protecting contents. Further, from the viewpoint of automatic packaging by a packaging machine, it is preferable that the difference between the layer in contact with the seal bar that is a heat source and the melting point of the seal layer on the inner surface side to be sealed by thermal fusion is larger. In addition, the high-rigidity film with low waist is easy for the operator to handle because it is easy to set in a packaging machine. From these viewpoints, biaxially oriented polypropylene (OPP) and biaxially oriented are generally excellent in heat resistance and high rigidity. Bonding stretched base film such as polyester (OPET), biaxially stretched polyamide (OPA), etc., unstretched polyethylene (PE), unstretched polypropylene (CPP), etc. with excellent sealing and sealing properties with an adhesive, Many laminate films have been used.

  However, from the viewpoint of environmental response in recent years, the volume of packaging materials used has been reduced by reducing the thickness of packaging materials, the laminating process has been reduced by the coextrusion method, the organic solvent used in adhesives has been reduced, and the adhesive itself has been reduced. Use and other factors are gaining importance among users and end consumers.

  In view of these requirements, the present inventor has already used heat-resistant polypropylene having a high melting point as a surface resin layer, and laminated a resin layer mainly composed of an olefin resin having a melting point lower than that of the polypropylene as a heat seal layer. Thus, a coextruded multilayer film that can be used alone without using a stretched base material, has excellent packaging machine suitability and excellent pinhole resistance, and a packaging material composed of the film have been proposed (for example, (See Patent Document 1).

  However, in response to demands such as cost reduction in the market, improvement in production speed has been demanded, and further improvement in heat resistance has been desired.

JP 2010-234660 A

  The object of the present invention has been made in view of the above problems, and has excellent surface heat resistance while having suitable packaging machine suitability, and can be used alone without using a stretched substrate or the like. It is providing a laminated film, its manufacturing method, and a packaging material using the same.

  Furthermore, the subject of this invention is providing the laminated film which was excellent in the packaging machine suitability with the said subject, and was excellent also in the adhesive strength of a heat-resistant coating layer and an olefinic film.

  As a result of diligent research to solve the above problems, the present inventors have provided a heat-resistant coating layer made of a cellulose acetate-based coating agent on a resin substrate having a heat-sealable thermoplastic resin layer, thereby improving surface heat resistance. It has been found that it can be effectively improved and that a suitable heat sealing property can be realized, and the present invention has been completed.

  That is, the present invention is a laminated film having a heat-resistant coating layer on a resin substrate, the surface of the resin substrate having a heat-resistant coating layer is a surface layer on the other surface is a heat-sealable thermoplastic resin layer, The heat-resistant coating layer is a layer made of a cellulose acetate coating agent, and provides a laminated film and a packaging material using the laminated film.

  Since the heat-resistant thermoplastic laminated film of the present invention has a heat-resistant coating layer made of a cellulose acetate-based coating agent and can achieve extremely high heat resistance with a simple structure, it has a high heat seal temperature even in a thinned structure. Heat sealing is possible, and the temperature range that can be sealed is greatly expanded, which can greatly contribute to the improvement of production efficiency and the reduction of manufacturing costs. Moreover, it can obtain simply by apply | coating a heat-resistant coating agent on the resin base material which has a heat-sealable thermoplastic resin layer. The design can be easily changed by selecting the layer structure of the multilayer film according to the target performance (transparency, rigidity, workability, etc.) and application (packaging material, poster, label, etc.). Excellent.

  The present invention is a laminated film having a heat-resistant coating layer on a resin substrate, the surface of the resin substrate having a heat-resistant coating layer on the other surface is a heat-sealable thermoplastic resin layer, It is a laminated film in which the coat layer is a layer made of a cellulose acetate-based coating agent.

[Resin substrate]
The resin substrate used in the present invention is a resin substrate having one surface made of a heat-sealable thermoplastic resin layer (hereinafter referred to as a heat-sealable thermoplastic resin layer (A1)). In the laminated film of the present invention, the surface made of the heat-sealable thermoplastic resin layer becomes one surface layer, and the other surface becomes the surface made of a heat-resistant coating layer.

  The heat-sealable thermoplastic resin layer (A1) used in the present invention is a layer mainly composed of a heat-sealable thermoplastic resin (hereinafter referred to as heat-sealable thermoplastic resin (a1)). As the heat-sealable thermoplastic resin, heat-sealable thermoplastic resins used for packaging materials and the like can be used, and polyolefin-based resins, polyester-based resins, and polystyrene-based resins can be preferably used. Especially, since it is easy to obtain suitable heat-sealing property at low cost, polyolefin resin can be preferably used.

  Examples of the polyolefin resin that can be used here include homopolymers or copolymers of α-olefins having 2 to 6 carbon atoms. The copolymerization type may be a block copolymer or a random copolymer. Moreover, as polyolefin resin, it is preferable to use what has the melting | fusing point of 100 degreeC or more from a viewpoint of the maintenance of the external appearance at the time of secondary shaping | molding, and suppression of the curvature of film itself.

  As the polyolefin resin, for example, any of those known as a polypropylene resin, a polyethylene resin, a cyclic olefin resin, or the like can be used. For example, as a polypropylene resin, a propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, an ethylene-propylene block copolymer, a metallocene catalyst And polypropylene. These may be used alone or in combination of two or more. When the obtained heat-resistant olefin-based multilayer film is rolled up and stored for a long period of time, it is preferable to use a crystalline propylene-based resin from the viewpoint of preventing blocking. In addition, in this application, crystallinity means having a peak of 0.5 J / g or more in the range of 95-250 degreeC in DSC (differential scanning calorimetry).

The polypropylene resin has a melt flow rate (hereinafter referred to as “230 ° C. MFR”; a value measured at 230 ° C. and 21.18 N in accordance with JIS K7210: 1999) of 0.5 to 30. Those having a melting point of 120 to 165 ° C. at 0.0 g / 10 min are preferred, and more preferably those having an MFR of 230 ° C. of 2.0 to 15.0 g / 10 min and a melting point of 125 to 162 ° C. . If the MFR and the melting point are in this range, the film shrinkage is small even when secondary molding such as heat molding is performed after multilayering, so that the appearance can be maintained and the warping of the medium itself does not occur. The film formability when a coextruded multilayer film is also improved. It is preferable that density is 0.890~0.910g / cm ^3, more preferably 0.895~0.905g / cm ^3.

  In particular, when a propylene-ethylene block copolymer is used as the heat-sealable thermoplastic resin (a1), the surface is modified to a satin finish, and the generation of wrinkles when winding the multilayer film into a roll is suppressed. In addition, blocking when stored in a roll can be reduced. Here, the propylene-ethylene block copolymer is a resin obtained by block polymerization of propylene and ethylene. For example, propylene obtained by polymerizing ethylene or ethylene and propylene in the presence of a propylene homopolymer. -An ethylene block copolymer etc. are mentioned.

  Further, when a mixed resin of a crystalline propylene-based resin and ethylene / propylene rubber (hereinafter referred to as “EPR”) is used, the surface of the layer (A1) can be easily modified into a satin finish. As the crystalline propylene-based resin used at this time, a highly versatile propylene homopolymer is preferable. On the other hand, as the EPR used at this time, those having a weight average molecular weight in the range of 400,000 to 1,000,000 are preferable in that irregularities are formed on the film surface and the surface can be modified into a satin finish, A range is more preferable. In addition, the EPR content in the mixed resin is preferably in the range of 5 to 35% by mass in that the film surface can be uniformly modified into a satin finish. The MFR (230 ° C.) of the mixed resin of the crystalline propylene polymer and EPR is preferably in the range of 0.5 to 15 g / 10 minutes from the viewpoint of easy extrusion. In addition, the weight average molecular weight of the EPR was obtained by calculating a component extracted from the mixed resin by a cross fractionation method at 40 ° C. using orthodichlorobenzene as a solvent by GPC (gel permeation chromatography). It is. The content of EPR in the mixed resin is obtained from the amount of EPR extracted by cross-fractionation at 40 ° C. using orthodichlorobenzene as a solvent.

  The method for producing the mixed resin of the crystalline propylene-based resin and EPR is not particularly limited. As a specific example, for example, a propylene homopolymer and ethylene / propylene rubber are separately mixed using a Ziegler type catalyst. After producing by a combination method, a slurry polymerization method, a gas phase polymerization method, etc., a propylene homopolymer is produced in the first stage by a method of mixing both with a mixer or a two-stage polymerization method, and then the second stage. And a method of generating EPR in the presence of this polymer.

  The Ziegler-type catalyst is a so-called Ziegler-Natta catalyst, and is obtained by supporting a transition metal compound such as a titanium-containing compound or a transition metal compound on a support such as a magnesium compound. The combination with the promoter of an organometallic compound is mentioned.

Examples of the polyethylene-based resin, a density of 0.900 g / cm ³ or more 0.970 g / cm ³ less than the ethylene-based resin is preferably exemplified specifically a resin, for example, ultra low density polyethylene (VLDPE), Polyethylene resins such as linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and ethylene-vinyl acetate copolymer Copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene Ethylene copolymers such as crylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA); furthermore, ionomers of ethylene-acrylic acid copolymers, ionomers of ethylene-methacrylic acid copolymers, etc. Can be mentioned. Of these, LDPE, LLDPE, LMDPE, and MDPE are preferred because of their good pinhole resistance.

The density of the ethylene-based resin as described above is preferably less than 0.900 g / cm ³ or more 0.970 g / cm ^3, is particularly in a range of less than 0.905 g / cm ³ or more 0.965 g / cm ³ It is more preferable. As long as it corresponds to this density, two or more types of polyethylene resins may be blended. If the density is less than 0.900 g / cm ³ , the rigidity may decrease and the suitability of the packaging machine may deteriorate. On the other hand, if it is 0.970 g / cm ³ or more, the pinhole resistance may be deteriorated. If the density is within this range, it has appropriate rigidity, excellent mechanical strength such as pinhole resistance, and film film formability and extrusion suitability are improved. Moreover, it is preferable that melting | fusing point is the range of 95-130 degreeC, and 100-125 degreeC is more preferable. If the melting point is within this range, the film shrinkage is small even when heated at the time of coating or secondary molding of the heat-resistant coating layer, so that the appearance of the film can be maintained and the warping of the film itself can be suppressed. it can. In addition, when this multilayer film is used to form a packaging bag, that is, when the layers (A1) are heat sealed with the layers (A1) inside, the sealing property is excellent. These may be used alone or in combination of two or more.

  Examples of the cyclic polyolefin resin include a norbornene polymer, a vinyl alicyclic hydrocarbon polymer, and a cyclic conjugated diene polymer. Among these, norbornene-based polymers are preferable. The norbornene polymer includes a ring-opening polymer of a norbornene monomer (hereinafter referred to as “COP”), a norbornene copolymer obtained by copolymerization of a norbornene monomer and an olefin such as ethylene (hereinafter referred to as “COP”). , “COC”). Furthermore, COP and COC hydrogenates are particularly preferred. The weight average molecular weight of the cyclic olefin resin is preferably 5,000 to 500,000, more preferably 7,000 to 300,000.

  The norbornene polymer and the norbornene monomer used as a raw material are alicyclic monomers having a norbornene ring. Examples of such norbornene-based monomers include norbornene, tetracyclododecene, ethylidene norbornene, vinyl norbornene, ethylidene tetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenyl norbornene, methoxycarbonyl norbornene, methoxycarbonyl And tetracyclododecene. These norbornene monomers may be used alone or in combination of two or more.

  The norbornene-based copolymer is a copolymer of the norbornene-based monomer and an olefin copolymerizable with the norbornene-based monomer, and examples of such olefin include the number of carbon atoms such as ethylene, propylene, and 1-butene. Examples thereof include olefins having 2 to 20; cycloolefins such as cyclobutene, cyclopentene, and cyclohexene; and non-conjugated dienes such as 1,4-hexadiene. These olefins can be used alone or in combination of two or more.

  As a commercial product that can be used as the cyclic polyolefin resin (a), examples of the ring-opening polymer (COP) of the norbornene monomer include “ZEONOR” manufactured by Nippon Zeon Co., Ltd., and norbornene. Examples of the system copolymer (COC) include “Appel” manufactured by Mitsui Chemicals, Inc., “TOPAS” manufactured by Polyplastics Co., Ltd., and the like.

  Furthermore, the MFR (190 ° C., 21.18N) of the polyethylene-based resin is preferably 2 to 20 g / 10 min from the viewpoint of improving the processing stability and the processability when coextruding with another resin layer. More preferably, it is 10 g / 10min.

  As the heat-sealable thermoplastic resin (a1) of the heat-sealable thermoplastic resin layer (A1) used in the present invention, the above-mentioned various polyolefin resins, polyester resins and polystyrene resins should be used alone. However, a plurality of resins may be used in combination. It is preferable that 50% by mass or more in the heat-sealable thermoplastic resin used for the heat-sealable thermoplastic resin layer (A1) is a polyolefin-based resin, more preferably 70% by mass or more, and 80% by mass or more. Is more preferable, and it is especially preferable that it is 90 mass% or more.

  Moreover, when using the obtained film as a package, the heat-sealable thermoplastic resin layer (A1) is composed of 1-butene and propylene as essential components as described in JP-A-2006-213065. -It can be set as an easily openable bag by setting it as the heat seal layer containing the butene-type copolymer and the copolymer which has propylene and ethylene as an essential component.

  In the heat-sealable thermoplastic resin layer (A1), as the components other than the heat-sealable thermoplastic resin (a1), if necessary, other resin components, antifogging agents, antistatic agents, heat stabilizers In addition, components such as a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a mold release agent, an ultraviolet absorber, and a colorant can be added within a range that does not impair the object of the present invention. In particular, the surface friction coefficient is preferably 1.5 or less, more preferably 1.0 or less in order to impart processing suitability when forming a film or packaging suitability when used as a packaging material. It is preferable to add an antistatic agent as appropriate. When these additives such as a lubricant and an antistatic agent are contained, 10 parts by mass or less is preferable with respect to 100 parts by mass of the resin component contained in the heat-sealable thermoplastic resin layer (A1). -5 mass parts is more preferable.

  The heat-sealable thermoplastic resin layer (A1) may be a single layer or a multilayer structure having two or more layers. From the viewpoint of more excellent rigidity, heat resistance and transparency, a film having a single layer or a multilayer structure mainly composed of a polypropylene resin is preferable.

  The resin base material used in the present invention may be a resin base material composed only of the heat sealable thermoplastic resin layer (A1) as long as the heat sealable thermoplastic resin layer (A1) is included in the surface layer. Or the resin base material by which the heat-sealable thermoplastic resin layer (A1) and the other layer were laminated | stacked may be sufficient. In the case where the resin base material is composed only of the heat-sealable thermoplastic resin layer (A1), it is preferable because it can greatly contribute to the volume reduction of the packaging material by reducing the thickness of the obtained laminated film and the manufacturing cost. Moreover, when aiming at various functional improvement, the resin base material on which the other layer was laminated | stacked can be used preferably.

  As another layer laminated | stacked on the said heat-sealable thermoplastic resin layer, the anchor coat layer which improves the adhesiveness of a heat-resistant coating layer can be illustrated preferably, for example. The anchor coat layer is not particularly limited as long as it can improve the adhesion of the heat resistant coat layer, and an anchor coat layer made of various anchor coat agents and resin films can be used.

  Among them, a layer containing an acid-modified olefin resin (hereinafter referred to as a layer (A2) containing an acid-modified olefin resin) is provided as an anchor coat layer on the surface of the resin base material on which the heat-resistant coating layer is provided. preferable. The layer containing the acid-modified olefin resin is particularly excellent in the coating properties of the cellulose acetate-based coating agent and the adhesion to the heat-resistant coating layer made of the coating agent, and impact (rubbing, heating, etc.) during secondary processing It is possible to particularly suitably suppress peeling due to.

  Although the olefin component which is the main component of the acid-modified polyolefin resin (hereinafter referred to as acid-modified olefin resin (a2)) used for the layer (A2) containing the acid-modified olefin resin is not particularly limited, ethylene, propylene , Alkenes having 2 to 6 carbon atoms such as isobutylene, 2-butene, 1-butene, 1-pentene and 1-hexene are preferable, and a mixture thereof may be used. Among these, alkene having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene is more preferable, ethylene and propylene are further preferable, and ethylene is most preferable. Moreover, the acid-modified polyolefin resin (a2) needs to contain a (meth) acrylic acid ester component. (Meth) acrylic acid ester components include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid Examples include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. From the viewpoint of easy availability and adhesiveness, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and hexyl acrylate are more preferable, and methyl acrylate and ethyl acrylate are more preferable. The (meth) acrylic acid ester component may be copolymerized with the olefin component, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization. (Graft modification) and the like. (In addition, "(meth) acrylic acid ~" means "acrylic acid ~ or methacrylic acid ~".) Specifically, as an ethylene- (meth) acrylic acid ester copolymer, for example, Elvalloy ( Product name: Mitsui-DuPont Polychemical Co., Ltd.), Aklift (trade name: Sumitomo Chemical Co., Ltd.), etc. These may be used alone or in combination of two or more.

  Further, the acid-modified polyolefin resin (a2) may be acid-modified with an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, as well as unsaturated dicarboxylic acid half esters and half amides. It is done. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable. The unsaturated carboxylic acid component may be copolymerized with the olefin component, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (grafting). Modification). Specifically, examples of the ethylene-acrylic acid copolymer include Nucrel (trade name: Mitsui / DuPont Polychemical Co., Ltd.). Examples of the ethylene- (meth) acrylic acid ester-maleic anhydride copolymer include bondine (trade name: manufactured by Tokyo Materials Co., Ltd.). These may be used alone or in combination of two or more.

  As the acid modification rate of the acid-modified olefin resin (a2), adhesion with a cellulose acetate-based coating agent to be described later, blocking suppression when winding and storing a multilayer film, and after applying the coating agent It is preferable to use 3 to 40%, more preferably 7 to 35%, and more preferably 10 to 30% from the viewpoint of excellent balance such as suppression of appearance defects such as wrinkles of the film in the drying step. Is most preferred.

  The layer (A2) containing the acid-modified polyolefin resin may further use other resins in addition to the acid-modified olefin resin (a2). In particular, it is preferable to use a polyolefin resin in combination from the viewpoint of easy mixing with the acid-modified olefin resin (a2) and easy co-extrusion with the heat-sealable thermoplastic resin layer (A1).

  The content of the acid-modified polyolefin resin (a2) in the layer (A2) containing the acid-modified polyolefin resin is preferably 3% by mass or more, more preferably 5% by mass or more, and 10% by mass. More preferably, it is the above.

  As the polyolefin resin, any of those exemplified for the heat-sealable thermoplastic resin (a1) used for the layer (A1) can be suitably used. At this time, the thermoplastic resins used in the layer (A1) and the layer (A2) may be the same or different. The polyolefin resin used in the layer (A2) may be a single resin or a mixture of plural kinds.

  In the layer (A2), it is preferable to use a polyolefin resin other than the acid-modified polyolefin resin (a2) in combination. As the polyolefin resin, the polyolefin resin exemplified in the resin (a1) used for the layer (A1) can be suitably used. The content of the polyolefin resin other than the resin (a2) in the resin component contained in the layer (A2) is preferably less than 90% by mass, and more preferably less than 80% by mass.

  The resin component used for the layer (A2) may contain any other resin in addition to the polyolefin resin other than the acid-modified polyolefin resin (a2) and the acid-modified polyolefin resin (a2). The content of the resin component other than the polyolefin-based resin is preferably less than 30% by mass in the resin component.

  For the layer (A2) containing the acid-modified polyolefin resin, an antifogging agent, an antistatic agent, a thermal stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a release agent, and an ultraviolet ray are optionally added. Components such as an absorbent and a colorant can be added as long as the object of the present invention is not impaired. In particular, the surface friction coefficient is preferably 1.5 or less, more preferably 1.0 or less in order to impart processing suitability when forming a film or packaging suitability when used as a packaging material. It is preferable to appropriately add a lubricant, an antiblocking agent, or an antistatic agent to the corresponding resin layer. When these additives such as a lubricant and an antistatic agent are contained, 10 parts by mass or less is preferable with respect to 100 parts by mass of the resin component contained in the layer (A2) containing the acid-modified polyolefin resin. 1-5 mass parts is more preferable.

  The thickness of the resin substrate used in the present invention can be appropriately set according to the use of the film. For example, in the case of a packaging material (bag or lid material), the thickness is 20 to 70 μm. In the case of a label or poster, it is preferably in the range of 70 to 1000 μm.

  As a resin base material, a resin base material obtained by laminating the heat-sealable thermoplastic resin layer (A1) and a layer (A2) containing an acid-modified polyolefin resin, in particular, a resin comprising only the layer (A1) and the layer (A2) When the base material is used, the ratio of the thickness of the layer (A2) to the total thickness of the layers (A1) and (A2) is 5 to 50% because adhesion with the heat-resistant coating layer is particularly easily secured. The thickness of the layer (A2) is preferably in the range of 2 to 40 μm.

  As a method of laminating the heat-sealable thermoplastic resin layer (A1) and the layer (A2) containing the acid-modified polyolefin resin, the layer (A1) and the layer (A2) are laminated adjacently. The extrusion lamination molding method is preferable. By using the co-extrusion method, steps such as coating and lamination can be omitted, and there are effects of reducing environmental burdens and manufacturing time and costs, which are extremely useful in practical use.

  As the coextrusion method, for example, a layer (A1) and a layer (A2) in a molten state by various coextrusion methods such as a coextrusion multilayer die method and a feed block method, which are melt-extruded using two or more extruders. After laminating, a method of processing into a long wound film by a method such as inflation or T-die / chill roll method is particularly preferable, and a co-extrusion method using a T-die is most preferable.

  The surface having the heat-resistant coating layer obtained in this configuration is a layered film characterized in that the surface layer on the other side is a layer composed of a heat-sealable thermoplastic resin layer, Also good.

  The stretching may be uniaxial stretching that extends only in the longitudinal direction (MD direction) or the width direction (TD direction), or may be biaxial stretching that extends both. In the stretching process, when the surface layer is a layer composed of a heat-sealable thermoplastic resin layer, when the heat-resistant coating layer is applied by coating after stretching or the surface having the heat-resistant coating layer is the surface layer on the other side May be stretched after making a laminated film having a layer comprising a heat-sealable thermoplastic resin layer.

  The stretching ratio when stretching in the longitudinal direction (MD direction) of the multilayer sheet is preferably 2 to 10 times, and if it is less than 2 times, improvement in mechanical strength and moisture resistance due to stretching is insufficient, and exceeding 10 times Since the tear strength of the obtained stretched film is lowered, it is not preferable.

  The stretching ratio in stretching in the width direction (TD direction) is preferably 2 to 20 times, and if it is less than 2 times, improvement in mechanical strength and moisture resistance due to stretching is insufficient. Uneven thickness is generated, which is not preferable.

  The stretching temperature is not limited because it affects the properties of each resin, but is 60 to 180 ° C, preferably 80 to 160 ° C. It is preferable to perform heat setting after completion of stretching. Heat setting can be performed by a known method, preferably 80 to 170 ° C, more preferably 100 to 160 ° C.

  In addition, the surface of the layer (A2) containing the acid-modified polyolefin resin may be continuously subjected to surface treatment using corona discharge or plasma discharge under heating or in an inert gas atmosphere during the production of the multilayer film. .

  The resin base material used for the laminated film of the present invention may appropriately use a layer other than the above layers (A1) and (A2) depending on the application to be used. For example, when used as a lid member, it can be easily opened by adopting a multilayer structure as described in JP-A-2004-75181 and JP-A-2008-80543. . Further, when a cyclic polyolefin-based resin as described in JP 2010-234660 A is used as one layer in a multilayer structure, it is possible to obtain a film having easy tearability, It is preferable to employ a multilayer structure.

  The resin base material used for the laminated film of the present invention, particularly the surface of the resin base material on the side where the heat-resistant coating layer is provided, may be provided with a decorative layer such as letters, figures and symbols by printing or the like. The decoration layer may be provided on a part of the surface of the resin base material, or may be provided on the entire surface, or a plurality of decoration layers may be laminated. The method for providing the decoration layer is preferable because the printing method is simple, and examples of the printing method include a silk printing method, a screen printing method, a gravure printing method, a flexographic printing method, and a thermal transfer printing method.

  As the ink used in the silk printing method and the screen printing method, various inks used for printing on a film can be used, and a solvent system or a UV curing system is used. In particular, solvent-based inks are preferably used because they only need to dry the solvent in a drying furnace, and therefore can be printed at low cost because no device such as a UV irradiation device is required. As the ink used for the thermal transfer system, a resin type or a wax type is used. Of these, the resin type is preferably used because of its excellent weather resistance.

[Heat-resistant coating layer]
The heat-resistant coating layer (hereinafter referred to as heat-resistant coating layer (B)) used in the present invention is a heat-resistant coating layer comprising a cellulose acetate-based coating agent (hereinafter referred to as cellulose acetate-based coating agent (b)). The heat-resistant coating layer (B) can impart extremely high heat resistance to the heat-sealable laminated film. Further, the heat resistance coating layer (B) used in the present invention can favorably improve the wear resistance and pinhole resistance.

  The thickness of the heat-resistant coating layer (B) is preferably 0.2 μm to 50 μm in order to maintain a practical level of heat resistance and transparency and maintain good production efficiency. Taking into consideration the coating on the seal bar and the coating strength of the heat-resistant coating layer (B), a thickness in the range of 0.5 to 30 μm is more preferable.

  The cellulose acetate-based coating agent (b) used for the heat-resistant coating layer (B) is a coating agent containing at least cellulose acetate, a crosslinking agent and an organic solvent, and the cellulose acetate-based coating agent (b) is used as the resin base material. After coating on, the heat-resistant coating layer can be formed by volatilizing the organic solvent contained in the cellulose acetate-based coating agent (b).

  The cellulose acetate-based coating agent (b) is not particularly limited, and can be appropriately selected according to the drying speed and heat resistance performance of the coating. In particular, in the present invention, it is necessary to provide a coating layer having high heat resistance, transparency, and packaging mechanical properties from the viewpoint of forming a coating layer on the resin substrate.

  Cellulose acetate used in the cellulose acetate-based coating agent (b) that can easily impart such performance is a semi-synthetic polymer obtained by acetic esterifying cellulose, which is a natural polymer. Cellulose is a polymer having anhydroglucose as a repeating unit, and has three hydroxyl groups per repeating unit, and cellulose acetate resins having different properties depending on the degree of esterification (degree of substitution) are obtained. The degree of substitution is represented by an index called acetylation degree. All three hydroxyl groups are acetylated, that is, triacetyl cellulose has an acetylation degree of 62.5%. The acetylation degree of the cellulose acetate used in the present invention is preferably 40 to 70%, and more preferably 43 to 62%. The average degree of polymerization is preferably about 100 to 400.

  The cellulose acetate content in the cellulose acetate-based coating agent (b) is preferably 5% by mass or more, more preferably 10% by mass or more in terms of the solid content excluding the organic solvent.

  The cellulose acetate-based coating agent (b) may contain a crosslinking agent such as an isocyanate compound that can react with the unsubstituted hydroxyl group in order to further increase heat resistance, adhesion, and surface hardness.

  Various things can be used as polyisocyanate (b-1) used when manufacturing the cellulose acetate type coating agent (b) used by this invention. For example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, cyclohexane-1,3- or 1,4-diisocyanate, 1-isocyanato-3-isocyanatomethyl-3 , 5,5-trimethylcyclohexane (also known as isophorone diisocyanate; IPDI), dicyclohexylmethane-4,4′-diisocyanate (also known as hydrogenated MDI), 2- or 4-isocyanatocyclohexyl-2′-isocyanatocyclohexylmethane, 3- or 1,4-bis- (isocyanatomethyl) -cyclohexane, bis- (4-isocyanato-3-methylcyclohexyl) methane, 1,3- or 1,4-α, α, α'α'-tetra Methyl xylylene diisocyanate 2,4- or 2,6-diisocyanatotoluene, 2,2'-, 2,4'- or 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-naphthalene diisocyanate, p- Or m-phenylene diisocyanate, xylylene diisocyanate, or diphenyl-4,4′-diisocyanate can be used.

  Among these, the use of aromatic diisocyanate is desirable particularly when considering the mechanical strength and the like, and when considering the durability and light resistance, the aliphatic or cycloaliphatic diisocyanate compound is particularly desirable. Use is desirable. In addition, it is preferable to use aromatic diisocyanate because it is easy to obtain suitable adhesion to the printing layer, and when applying the cellulose acetate coating agent (b) on the printing layer, use MDI polyisocyanate. It is particularly preferable to do this.

  In order to further improve the heat resistance of the heat-resistant coating layer (B) obtained from the cellulose acetate-based coating agent (b), a crosslinking agent such as an amino resin, an epoxy compound, an aziridine compound, a carbodiimide compound, or an oxazoline compound is used in combination. There is no problem. Of these, amino resins and isocyanate compounds typified by melamine crosslinking agents are most preferred because of their fast reactivity. Two or more kinds of crosslinking agents may be used in combination, or an appropriate amount of a curing accelerator may be used in combination.

The addition amount of the crosslinking agent is preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the solid content of the cellulose acetate-based coating agent (b). If it is this range, the blocking resistance, heat resistance, heat-and-moisture resistance, and solvent resistance of the formed coating layer (B) will be improved without impairing the suitability when printing on the coating layer (B). It becomes possible to make it. In particular, when an isocyanate-based crosslinking agent is used as the crosslinking agent, the isocyanate-based crosslinking agent is used in a solid content of 100 parts by mass of the cellulose acetate-based coating agent (b), and the crosslinking agent is used in a solid content of 5 parts by mass or more. It is preferable to do.

  As an organic solvent used when producing the cellulose acetate-based coating agent (b), it is possible to use an organic solvent having a boiling point of 150 ° C. or less in consideration of removing the residual solvent contained in the coating layer. preferable.

Examples of the organic solvent having a boiling point of 150 ° C. or lower include MEK (methyl ethyl ketone), benzene, toluene, ethyl acetate, acetone, methyl ethyl ketone, diethyl ether, tetrahydrofuran, methyl acetate, acetonitrile, chloroform, and methylene chloride. These can be used alone or in combination. Among them, it is particularly preferable to use acetone, methyl ethyl ketone, toluene, and ethyl acetate as a solvent having high solubility for the cellulose acetate-based coating agent (b) .

  The cellulose acetate coating agent (b) includes nitrocellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, urethane resin, fluorine resin, acrylic resin, epoxy together with cellulose acetate. An organic polymer such as a resin or a polybutyral resin may be contained. Further, various lubricant components such as silicone oil, fluorine oil, higher fatty acid, paraffin, and fatty acid esters may be added as necessary.

  In addition, the cellulose acetate-based coating agent (b) may contain an acrylic resin, a polyester resin, a synthetic rubber resin such as SBR, or the like as long as the transparency and heat resistance are not impaired. These resins are preferably 30% or less, particularly preferably 10% or less, in terms of solid content in the coating agent.

  In addition, the cellulose acetate coating agent (b) may be supplemented with inorganic fine particles (colloidal silica) for improving blocking resistance or slip resistance, if necessary, and with an antistatic agent for improving wettability. An agent can also be blended.

  Furthermore, the cellulose acetate-based coating agent (b) preferably has a minimum film-forming temperature of 50 ° C. or lower, and more preferably 30 ° C. or lower. If it is this range, it will become possible to coat without forming pinholes that are likely to occur during film formation.

[Laminated film]
The laminated film of the present invention has a structure in which a heat-resistant coating layer (B) comprising the cellulose acetate-based coating agent (b) is provided on a resin substrate having the heat-sealable thermoplastic resin layer (A1). The laminated film is such that one surface of the laminated film is the surface of the heat-resistant coating layer (B) and the other surface is the surface of the heat-sealable thermoplastic resin layer (A1). Since the laminated film of the present invention can realize extremely high heat resistance with the simple structure without impairing the suitability of packaging machinery, the surface layer does not adhere to the seal bar even during heat sealing at high temperatures, and the seal bar It is possible to suitably suppress the deterioration of the appearance due to the occurrence of dirt and wrinkles on the seal portion. For this reason, even in a thinned configuration, heat sealing can be suitably performed at a high heat sealing temperature, which can greatly contribute to the reduction of manufacturing cost and can be used alone without using a stretched substrate.

  The thickness of the laminated film of the present invention may be adjusted as appropriate according to the application to be used, but when used for various packaging materials, the heat sealability and handleability are good when it is 15 to 150 μm. Therefore, it is preferable.

  The laminated film of the present invention is prepared by adjusting the cellulose acetate-based coating agent (b) to an arbitrary resin concentration, then applying the cellulose acetate coating agent on the resin substrate, and then drying, and performing a curing treatment such as thermosetting as necessary. It can be manufactured. The method for coating the cellulose acetate-based coating agent (b) on the resin substrate is not particularly limited. For example, coating such as an air knife coater, blade coater, roll coater, gravure coater, comma coater, gate roll coater, etc. A method using a machine is simple.

  The method of volatilizing the medium contained in the coating agent after coating the cellulose acetate-based coating agent (b) on the film is not particularly limited, but for example, drying using a dryer. The method is common. The drying temperature may be a temperature that can volatilize the medium and does not adversely affect the substrate.

  In the production of the multilayer film, the surface to which the heat-resistant coating layer is applied may be continuously subjected to surface treatment using corona discharge or plasma discharge under heating or in an inert gas atmosphere.

  Since the heat-resistant thermoplastic laminated film of the present invention can be obtained as a substantially unstretched multilayer film by the above-described production method, secondary molding such as deep drawing by vacuum molding, foil pressing, embossing, etc. is also possible. .

  The laminated film of the present invention may be provided with a decorative layer such as characters, figures and symbols on the heat-resistant coating layer (B) by printing or the like. As a method of providing the decoration layer, a printing method is preferable because it is simple. Examples of the printing method include a silk printing method, a screen printing method, a gravure printing method, and a thermal transfer printing method.

  When printing or the like is performed on the heat-resistant coating layer (B), it is preferable to perform a surface treatment on the resin base material layer in order to improve adhesion with printing ink. Examples of such surface treatment include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable.

  Since the laminated film of the present invention has suitable heat sealability and high heat resistance, it can be suitably applied to various packaging materials. Examples of the packaging material include packaging bags, containers, container lids and the like used for foods, medicines, industrial parts, miscellaneous goods, magazines and the like. In particular, it can be suitably used for medicines, industrial parts, foods and confectionery stored at room temperature, refrigerated and frozen, which are filled, packaged and sealed at high speed.

  The packaging material is heat-sealed by stacking layers (A1) with the heat-sealable thermoplastic resin layer (A1) side of the laminated film of the present invention as a heat-seal layer, or a layer (A1) and a heat-resistant coating layer (B ) Is heat-sealed and is preferably a packaging bag formed with the layer (A1) as the inner side. For example, after cutting out the two multilayer films into the desired size of a packaging bag and overlapping them to heat-seal three sides to form a bag, the contents are filled from one side that is not heat-sealed. It can be used as a packaging bag by heat sealing. Furthermore, it is also possible to form a packaging bag by sealing the upper and lower sides after sealing the end of a roll-shaped film into a cylindrical shape by an automatic packaging machine.

  It is also possible to form a lid of a packaging bag / container / container by heat-sealing with the heat-sealable thermoplastic resin layer (A1) and another film, sheet, or container that can be heat-sealed. In that case, as another film to be used, a film or sheet using a thermoplastic resin such as a polyethylene resin, a polypropylene resin, or a polyester resin can be used.

  In the packaging material using the heat-resistant olefin-based multilayer film of the present invention, any tear such as V-notch, I-notch, perforation, micro-porosity, etc. is used in the seal portion in order to weaken initial tear strength and improve openability. A starting portion may be formed.

  In addition, the laminated film of the present invention, after providing a pressure-sensitive adhesive layer on the heat-sealable thermoplastic resin layer (A1), heat-sealing the laminated film of the present invention and other resin films, A resealable packaging bag can also be provided.

  The type of the adhesive is not particularly limited. For example, natural rubber, synthetic rubber, acrylic, urethane, vinyl ether, silicone, amide and styrene adhesive, styrene elastomer, olefin elastomer Etc. For the purpose of controlling the adhesive properties, etc., the pressure-sensitive adhesive layer may include, for example, terpene resins such as α-pinene, β-pinene polymer, diterpene polymer, α-pinene / phenol copolymer, fat Appropriate tackifiers such as aromatic resins, aromatic resins, aliphatic / aromatic copolymer systems, other rosin resins, coumarone indene resins, (alkyl) phenol resins and xylene resins Can be blended. Among these, when laminating a layer (A1) and a layer (A2) to be described later by a coextrusion method, a method of simultaneously laminating an adhesive layer on the layer (A1) opposite to the layer (A2) by coextrusion Is preferable in the manufacturing cycle.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these. In the examples, “part” and “%” are based on mass unless otherwise specified.

[Preparation Example 1 of Cellulose Acetate Coating Agent (b-1)]
In a vessel equipped with a stirrer, 250 parts of acetone and 600 parts of toluene were charged, and 100 parts of cellulose acetate (L-20 manufactured by Daicel Corporation; acetylation degree 55%, 6% viscosity 50 mPa · s) was added and stirred. It was completely dissolved. To this, 25 parts of TDI polyisocyanate (Hardener No. 50 manufactured by DIC Corporation; nonvolatile content 50%) was added and completely dissolved to obtain a cellulose acetate coating agent (b-1) (nonvolatile content 11.5%). ) Was prepared.

[Preparation Example 2 for Cellulose Acetate-Based Coating Agent (b-2)]
In a container equipped with a stirrer, 300 parts of acetone and 600 parts of toluene were charged, and 100 parts of cellulose acetate (L-20 manufactured by Daicel Corporation; acetylation degree 55%, 6% viscosity 50 mPa · s) was added and stirred. It was completely dissolved. To this, 35 parts of MDI polyisocyanate (Hardener No. 10 manufactured by DIC Corporation; non-volatile content 60%) 35 parts was added and completely dissolved to obtain a cellulose acetate-based coating agent (b-2) (non-volatile content 11.5%). ) Was prepared.

[Preparation Example 3 for Cellulose Acetate-Based Coating Agent (b-3)]
A container equipped with a stirrer is charged with 300 parts of acetone, 600 parts of toluene, and 300 parts of N-methyl-2-pyrrolidone (NMP), and cellulose acetate (L-70 manufactured by Daicel Corporation; 60% acetylation, 6% viscosity) (50 mPa · s) 100 parts were added and completely dissolved while stirring. To this, 35 parts of MDI polyisocyanate (Hardener No. 10 manufactured by DIC Corporation; non-volatile content 60%) 35 parts was added and completely dissolved to obtain a cellulose acetate-based coating agent (b-2) (non-volatile content 11.5%). ) Was prepared.

Example 1
As the resin for the resin layer (A1), a propylene-ethylene copolymer [MFR: 8 g / 10 min (230 ° C., 21.18 N), melting point: 138 ° C .; hereinafter referred to as “COPP”] was used. As the resin for the resin layer (A2), ethylene- (meth) methyl acrylate copolymer (density: 0.940 g / cm ³ , MA content 18%; hereinafter referred to as “MA1”) was used. Each of these resins is supplied to an extruder for a resin layer (A1) (caliber 50 mm) and an extruder for a resin layer (A2) (caliber 50 mm) and melted at 200 to 250 ° C. Co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 250 ° C.) having T die / chill roll method and co-melt extrusion are carried out, and the layer structure of the film is (A1) / (A2) A two-layered coextruded multilayer film having a thickness of 45 μm / 5 μm (total 50 μm) was obtained. Film thickness after drying the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 after subjecting the surface of the (A2) layer of this support to corona discharge treatment so that the wetting tension is 40 mN / m. Was applied to give a heat-resistant olefin-based laminated film of Example 1.

(Example 2)
A heat-resistant olefin-based laminated film was prepared in the same manner as in Example 1 except that the cellulose acetate -based coating agent (b-1) in Example 1 was changed to the cellulose acetate-based coating agent (b-2) obtained in Preparation Example 2. Created.

(Example 3)
The acid-modified olefin resin of the resin layer (A2) of Example 1 was replaced with an ethylene-methyl acrylate copolymer (MA content 12%, density: 0.933 g / cm ³ ; hereinafter referred to as “MA2”). A heat-resistant olefin-based laminated film was prepared in the same manner as in Example 1 except that the cellulose acetate-based coating agent (b-1) was applied so that the film thickness after drying was 0.5 μm.

Example 4
The acid-modified olefin resin of the resin layer (A2) of Example 1 is an ethylene-methyl acrylate-maleic anhydride copolymer [density: 1.00 g / cm ³ , copolymer content: 15%; hereinafter referred to as “MA3”. A heat-resistant olefin-based laminated film was produced in the same manner as in Example 1 except that the description was replaced.

(Example 5)
50% of resin MA1 for resin layer (A2) of Example 2 and propylene-ethylene copolymer [density: 0.900 g / cm ³ , MFR: 7 to 9 g / 10 min (230 ° C., 21.18 N), Melting point: 150 ° C .; hereinafter referred to as “COPP”] A heat-resistant olefin-based laminated film was produced in the same manner as in Example 2 except that the composition was replaced with 50%.

(Example 6)
A heat-resistant olefin-based laminated film was produced in the same manner as in Example 1 except that the resin MA1 for the resin layer (A2) of Example 2 was replaced with a blend of 20% and COPP of 80%.

(Example 7)
COPP of the resin layer (A1) of Example 5 was made of high-density polyethylene [density: 0.93 g / cm ³ , MFR: 5 g / 10 min (190 ° C., 21.18 N), melting point 120 ° C .; hereinafter referred to as “MDPE”. A heat-resistant olefin-based laminated film was produced in the same manner as in Example 5 except that the description was replaced.

(Example 8)
COPP of the resin layer (A1) of Example 5 was changed to linear low density polyethylene [density: 0.905 g / cm ³ , MFR: 5.0 g / 10 min (190 ° C., 21.18 N), melting point 100 ° C .; , Described as “LLDPE”], and the thickness of each layer of the layer structure (A1) / (A2) of the film is 25 μm / 5 μm (total 30 μm), and the cellulose acetate-based coating agent (b-1) is dried. A heat-resistant olefin-based laminated film was produced in the same manner as in Example 5 except that the film thickness was 5 μm.

Example 9
Example 1 except that the acrylic acid-modified resin of Example 1 was replaced with an ethylene- (meth) acrylic acid copolymer [density: 0.940 g / cm ³ , acid modification rate 12%; hereinafter referred to as “MA4”] In the same manner as in Example 2, a heat-resistant olefin-based laminated film was produced.

(Example 10)
The thickness of each layer of the layer structure (A1) / (A2) of the film of Example 1 is 114 μm / 6 μm (total 120 μm), and the film thickness after drying the cellulose acetate coating agent (b-1) is 2 μm. A heat-resistant olefin-based laminated film was produced in the same manner as in Example 1 except that the coating was performed as described above.

(Example 11)
The thickness of each layer of the layer structure (A1) / (A2) of the film of Example 1 is 90 μm / 30 μm (total 120 μm), and the film thickness after drying the cellulose acetate-based coating agent (b-1) is 2 μm. A heat-resistant olefin-based laminated film was produced in the same manner as in Example 1 except that the coating was performed as described above.

(Example 12)
An olefin-based single layer film composed of the resin layer (A1) was produced in the same manner as in Example 1 except that the resin layer (A2) of Example 1 was not extruded. After performing a corona discharge treatment on one surface of this support so that the wetting tension is 40 mN / m, the film thickness after drying the cellulose acetate coating agent (b-3) obtained in Preparation Example 3 is 2 μm. The heat-resistant olefin-based laminated film of Example 12 was produced.

(Comparative Example 1)
An olefin-based laminated film was produced in the same manner as in Example 1 except that the cellulose acetate-based coating agent (b-1) was not applied.

  The films obtained in Examples 1 to 12 and Comparative Example 1 were evaluated as follows. The results obtained are shown in the table below.

[Evaluation of coating properties of cellulose acetate coating agent]
The coating agent was applied to an A4 size film with a bar coater so as to be 1.5 g / m ^2, and the number of repellings was measured visually.
○: No repelling.
X: There are one or more repels.

[Evaluation of heat resistance of film]
After coating the coating agent, the appearance of the film was visually evaluated when dried at 80 ° C. for 2 minutes.
○: Almost no defects in appearance such as kinks, wrinkles and film deformation.
Δ: Appearance defects such as slight kinks, wrinkles and film deformation are observed.
X: Appearance defects such as significant kinks, wrinkles, and film deformation are observed.

[Coating adhesion evaluation]
A cellophane tape (manufactured by Nichiban) peel test was conducted and visually evaluated.
○: No peeling of the coat layer.
X: There exists peeling of a coating layer.

[Packaging machine suitability]
The films prepared in Examples and Comparative Examples were subjected to the following vertical pillow packaging with an automatic packaging machine, made into bags, and evaluated as follows.
Packaging machine: Rika Kaken Co., Ltd. Unipacker NUV472

  Horizontal sealing: Resin layers (B) were sealed while changing at a rate of 30 bags / minute, a vertical heat seal temperature of 150 ° C., an air gauge pressure of 4 kg / cm 2, and a horizontal heat seal temperature of 140 ° C. to 200 ° C. in increments of 10 ° C. A flat bag measuring 200 mm long and 150 mm wide was used.

(Shrinkage / wrinkle test)
The appearance of the seal portion of the flat bag subjected to horizontal (gap-attached) sealing and vertical sealing was evaluated by shrinkage and the state of film fusion to the heat seal bar and the degree of wrinkles.
○: No shrinkage of seal part, fusion to seal bar, wrinkles, etc. Δ: Some shrinkage of seal part, fusion to seal bar, wrinkles, etc. Etc.

(Horizontal sealability)
The film made under the above conditions was naturally cooled at 23 ° C., and then a test piece was cut into a strip shape having a width of 15 mm. The test piece was peeled 90 ° at a rate of 300 mm / min using a tensile tester (manufactured by A & D Co., Ltd.) in a thermostatic chamber at 23 ° C. and 50% RH, and the heat seal strength was measured. The heat sealability was evaluated according to the following criteria from the obtained heat seal strength value.
○: Heat seal strength is 300 g / 15 mm width or more ×: Heat seal strength is less than 300 g / 15 mm width, or the melt / shrinkage of the film is large and measurement is impossible

(Example 13)
As the resin for the resin layer (A1), a propylene-ethylene copolymer [MFR: 8 g / 10 min (230 ° C., 21.18 N), melting point: 138 ° C .; hereinafter referred to as “COPP”] was used. As the resin for the resin layer (A2), ethylene- (meth) methyl acrylate copolymer (density: 0.940 g / cm ³ , MA content 18%; hereinafter referred to as “MA1”) was used. Each of these resins is supplied to an extruder for a resin layer (A1) (caliber 50 mm) and an extruder for a resin layer (A2) (caliber 50 mm) and melted at 200 to 250 ° C. Co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 250 ° C.) having T die / chill roll method and co-melt extrusion are carried out, and the layer structure of the film is (A1) / (A2) A two-layered coextruded multilayer film having a thickness of 45 μm / 5 μm (total 50 μm) was obtained. Film thickness after drying the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 after subjecting the surface of the (A2) layer of this support to corona discharge treatment so that the wetting tension is 40 mN / m. The coating layer was formed by coating and drying to a thickness of 1 μm. On the coating layer, nitrified cotton / urethane-based ink (c-1) (Ultima NT507 primary color indigo manufactured by DIC Graphics Co., Ltd.) was printed after drying so as to have a film thickness of 1 μm. A laminated film was produced.

(Example 14)
Except for using the nitrified cotton / polyamide-based ink (c-2) (Glossa 507 primary indigo produced by DIC Graphics) as the nitrified cotton / urethane-based ink (c-1) in Example 13, the same as in Example 13. A heat-resistant olefin-based laminated film was prepared.

(Example 15)
The same procedure as in Example 13 was repeated except that the nitrified cotton / urethane-based ink (c-1) in Example 13 was changed to urethane-based ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

(Example 16)
A heat-resistant olefin-based laminated film in the same manner as in Example 13 except that the cellulose acetate -based coating agent (b-1) in Example 13 is the cellulose acetate-based coating agent (b-2) obtained in Preparation Example 2. It was created.

(Example 17)
The same procedure as in Example 16 was conducted except that the nitrified cotton / urethane ink (c-1) in Example 16 was changed to nitrified cotton / polyamide ink (c-2) (Glosser 507 primary indigo produced by DIC Graphics). A heat-resistant olefin-based laminated film was prepared.

(Example 18)
The same procedure as in Example 16 was conducted except that the nitrified cotton / urethane ink (c-1) in Example 16 was urethane ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

(Example 19)
A heat-resistant olefin-based laminated film in the same manner as in Example 13 except that the cellulose acetate -based coating agent (b-1) in Example 13 is the cellulose acetate-based coating agent (b-3) obtained in Preparation Example 3. It was created.

(Example 20)
The same procedure as in Example 19 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 19 was changed to nitrified cotton / polyamide ink (c-2) (Glosser 507 primary color indigo manufactured by DIC Graphics). A heat-resistant olefin-based laminated film was prepared.

(Example 21)
The same procedure as in Example 19 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 19 was changed to urethane ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

  The following evaluation was performed about the film obtained in the said Examples 13-21. The results obtained are shown in the table below.

[Evaluation of coating properties of printing ink]
On the coat layer, the ink was applied to an A4 size film with a bar coater so as to be 1.5 g / m ^2, and the number of ink repelling was visually measured.
○: No repelling.
X: There are one or more repels.

[Evaluation of heat resistance of film]
The appearance of the film was visually evaluated when the printed film was dried at 80 ° C. for 2 minutes.
○: Almost no defects in appearance such as kinks, wrinkles and film deformation.
Δ: Appearance defects such as slight kinks, wrinkles and film deformation are observed.
X: Appearance defects such as significant kinks, wrinkles, and film deformation are observed.

(Example 22)
As the resin for the resin layer (A1), a propylene-ethylene copolymer [MFR: 8 g / 10 min (230 ° C., 21.18 N), melting point: 138 ° C .; hereinafter referred to as “COPP”] was used. As the resin for the resin layer (A2), ethylene- (meth) methyl acrylate copolymer (density: 0.940 g / cm ³ , MA content 18%; hereinafter referred to as “MA1”) was used. Each of these resins is supplied to an extruder for a resin layer (A1) (caliber 50 mm) and an extruder for a resin layer (A2) (caliber 50 mm) and melted at 200 to 250 ° C. Co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 250 ° C.) having T die / chill roll method and co-melt extrusion are carried out, and the layer structure of the film is (A1) / (A2) A two-layered coextruded multilayer film having a thickness of 45 μm / 5 μm (total 50 μm) was obtained. Corona discharge treatment was applied to the surface of the (A2) layer of the support so that the wetting tension was 40 mN / m, and then the nitrified cotton / urethane ink (c-1) (Ultima NT507 primary color indigo by DIC Graphics) was applied. It printed so that a film thickness might be set to 1 micrometer after drying. The cellulose acetate-based coating agent (b-1) obtained in Preparation Example 1 was applied to the obtained printed surface so as to have a film thickness after drying of 1 μm and dried to heat-resistant olefin-based laminate of Example 22. A film was prepared.

(Example 23)
The same procedure as in Example 22 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 22 was changed to nitrified cotton / polyamide ink (c-2) (Glosser 507 primary indigo produced by DIC Graphics). A heat-resistant olefin-based laminated film was prepared.

(Example 24)
The same procedure as in Example 22 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 22 was changed to urethane ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

(Example 25)
A heat-resistant olefin-based laminated film in the same manner as in Example 22 except that the cellulose acetate -based coating agent (b-1) in Example 22 is the cellulose acetate-based coating agent (b-2) obtained in Preparation Example 2. It was created.

(Example 26)
The same procedure as in Example 25 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 25 was changed to nitrified cotton / polyamide ink (c-2) (Glosser 507 primary indigo produced by DIC Graphics). A heat-resistant olefin-based laminated film was prepared.

(Example 27)
The same procedure as in Example 25 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 25 was changed to urethane ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

(Example 28)
A heat-resistant olefin-based laminated film in the same manner as in Example 22 except that the cellulose acetate -based coating agent (b-1) in Example 22 is the cellulose acetate-based coating agent (b-3) obtained in Preparation Example 3. It was created.

(Example 29)
The same procedure as in Example 28 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 28 was changed to nitrified cotton / polyamide ink (c-2) (Glosser 507 primary color indigo manufactured by DIC Graphics). A heat-resistant olefin-based laminated film was prepared.

(Example 30)
The same procedure as in Example 28 was repeated except that the nitrified cotton / urethane ink (c-1) in Example 28 was changed to urethane ink (c-3) (Univia NT R507 primary color indigo K-1 manufactured by DIC Graphics). Thus, a heat-resistant olefin-based laminated film was prepared.

  The following evaluation was performed about the film obtained in the said Examples 22-30. The results obtained are shown in the table below.

[Evaluation of coating properties of cellulose acetate coating agent]
On the printed surface, a coating agent was applied to an A4 size film at 1.5 g / m ² with a bar coater, and the number of repellings was measured visually.
○: No repelling.
X: There are one or more repels.

[Evaluation of heat resistance of film]
After coating the coating agent, the appearance of the film was visually evaluated when dried at 80 ° C. for 2 minutes.
○: Almost no defects in appearance such as kinks, wrinkles and film deformation.
Δ: Appearance defects such as slight kinks, wrinkles and film deformation are observed.
X: Appearance defects such as significant kinks, wrinkles, and film deformation are observed.

  As is clear from the above table, the laminated films of the present invention of Examples 1 to 12 were excellent in surface heat resistance and had suitable packaging machine suitability. On the other hand, the laminated film of Comparative Example 1 having no heat-resistant coating layer had low heat resistance and was inferior in packaging machine suitability at a high heat seal temperature. Moreover, as shown in Examples 13 to 21, the laminated film of the present invention was capable of printing with various inks on the heat-resistant coating layer, and had suitable printability. Moreover, as shown in Examples 22 to 30, a coat layer can be suitably laminated even when a resin film having a printed layer surface is used, and in particular, lamination of Examples 23 to 24, 26 to 27, and 28 to 29. The film was particularly excellent in the adhesion of the coat layer.

Claims (14)

A laminated film used for a packaging material, having a heat-resistant coating layer on a resin substrate, and the surface of the resin substrate having the heat-resistant coating layer is a heat-sealable thermoplastic resin layer on the other surface. , laminated film said refractory coating layer Ri layer der consisting a cellulose acetate coating, the resin base material is characterized in that it consists of an extruded resin film.   The laminated film according to claim 1, wherein the cellulose acetate-based coating agent contains cellulose acetate, a crosslinking agent, and an organic solvent, and the acetylation degree of the cellulose acetate is 40 to 70%.   The laminated film according to claim 2, wherein the organic solvent is an organic solvent having a boiling point of 150 ° C or lower. The laminated film according to any one of claims 1 to 3, wherein the heat-resistant coating layer has a thickness of 0.1 to 10 µm.   The laminated film according to any one of claims 1 to 4, wherein the resin base material comprises a heat-sealable thermoplastic resin layer.   The laminated film according to any one of claims 1 to 4, wherein the resin base material has a heat-sealable thermoplastic resin layer and a layer containing an acid-modified olefin resin.   The laminated film according to claim 6, wherein the resin base material is formed by co-extrusion of a heat-sealable thermoplastic resin and an acid-modified olefin resin. The laminated film according to any one of claims 1 to 7, wherein 50% by mass or more of the thermoplastic resin contained in the heat-sealable thermoplastic resin layer is a polyolefin resin. The laminated film according to claim 1, wherein the resin base material has a thickness of 20 to 70 μm.   The laminated film according to claim 1, further comprising a printed layer on the heat resistant coating layer.   The laminated film according to any one of claims 1 to 10, wherein the resin substrate is a resin substrate having a printed layer on a surface layer having a heat-resistant coating layer.   A packaging material using the laminated film according to claim 1.   The packaging material according to claim 12, wherein the laminated film is used alone.   The packaging material according to claim 12 or 13, wherein the laminated film is formed into a bag with the heat-sealable thermoplastic resin layer side surface as an inner surface.