JP2016050033A - Lid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid material for a sealed container such as a straw which has easily-penetrability and can achieve high heat resistance.SOLUTION: A lid material for a sealed container has a heat resistant coat layer on a resin base material. A surface layer on the other side of the side having the heat resistant coat layer of the resin base material is formed of a heat-sealable thermoplastic resin layer. The resin base material is a resin base material of which a piercing strength when a 0.5 mmR semi semispherical needle pierces the resin base material at a piercing speed of 50 mm/min is less than 6 N. A favorable seal strength and excellent low adsorptivity can be achieved by a lid material of which the heat resistant coat layer is a layer formed of a cellulose acetate-based coating agent.SELECTED DRAWING: None

Description

  The present invention relates to a lid member that seals the mouth of a container filled with a liquid or gel-like material such as a beverage or jelly.

  Conventionally, as a lid to seal the opening of containers filled with liquids or gels such as beverages (teas and juices) and jelly, overcaps with straws and opening blades, etc. without removing the lid from the container Thus, a lid material is used in which an opening is directly formed in the lid material and the contents can be taken out (see, for example, Patent Documents 1 and 2). As such a lid material, since easy penetrability by a tip of a straw or an opening blade is required, a film using an easily penetrable resin provided with an aluminum foil layer is widely used (for example, , See Patent Document 2).

  In addition, as a cover material that does not use an aluminum foil layer, for example, a multilayer cover material having a laminate structure in which a paper base material is disposed in an intermediate layer, biaxially oriented polypropylene on one side, polyethylene terephthalate on the other side, and a sealant layer is provided. It has been proposed (see, for example, Patent Document 3).

JP 2010-2222051 A JP 2010-269848 A JP 2004-136918 A

  The lid material using the aluminum foil layer disclosed in Patent Document 2 exemplified above guarantees easy penetration by the aluminum foil, but when the film having the aluminum foil layer as a surface layer is printed. However, there is a problem that ink dullness occurs due to the metallic luster of the aluminum foil, and the color developability of the ink is inferior. In addition, when aluminum foil is used, there is a problem that separation and recycling at the time of disposal tend to be complicated, and energy consumption during production and carbon dioxide emission are increased. Further, when aluminum foil is used, there is a problem that a metal detector cannot be used in quality checks such as contamination inspection in food applications. Due to these problems, there has been a strong demand in the market for a lid material having easy penetration without using an aluminum foil.

  The lid material disclosed in Patent Document 3 exemplified above is a lid material that does not use an aluminum foil layer. However, in order to suppress moisture permeability and ensure heat resistance during heat sealing, the lid material is not provided on both sides of the paper substrate. It is a cover material that requires a complicated and multilayer structure provided with a laminate layer of axially stretched polypropylene or polyethylene terephthalate. From the viewpoint of environmental response in recent years, the volume of materials used has been reduced by reducing the thickness of the cover material, the lamination process has been reduced by the coextrusion method, the organic solvent used in the adhesive has been reduced, and the adhesive has not been used. There is a high demand, and there has been a demand for a lid that can achieve easy penetration and heat resistance with a simple configuration and man-hours. Moreover, the lid material used for these foods and the like is extremely demanded for cost reduction, and as a measure for reducing production cost, the heat sealing temperature is raised to increase the production speed by shortening the sealing time. Therefore, the high heat resistance which can be heat-sealed under high temperature was calculated | required.

  The problem to be solved by the present invention is to provide a lid member for a sealed container that has easy penetration such as a straw and can realize high heat resistance in response to the above demand.

  Furthermore, the present invention is to provide a lid for a sealed container that has the above excellent heat resistance and easy penetration without using an aluminum foil, and is easy to manufacture.

  The present invention is a lid used for a sealed container, having a heat-resistant coating layer on a resin base material, a surface layer on the other side comprising a heat-sealable thermoplastic resin layer, and the heat-resistant coating layer being a cellulose acetate type It is an object of the present invention to provide an easy-penetrating lid material that is a layer made of a coating agent.

  The lid material of the present invention has a heat-sealable thermoplastic resin layer, and is provided with a heat-resistant coating layer made of a cellulose acetate-based coating agent on a resin base material having a piercing strength of less than 6N, thereby allowing easy penetration. The surface heat resistance can be effectively improved while maintaining the properties. For this reason, heat sealing at a high heat sealing temperature is possible, and the temperature range that can be sealed is greatly expanded, which can greatly contribute to improvement in production efficiency. In addition, high heat resistance can be achieved by applying a coating layer without using a laminate layer, making it possible to reduce the thickness and manufacture with a simple configuration and man-hours. It is an advantage.

  Since the lid material of the present invention can realize suitable easy penetration and heat sealability without using aluminum foil, the dullness of ink due to the influence of metallic luster and the reduction of color development do not occur, and the design and print finish It is possible to realize a lid material having good color matching properties. In addition, by not using aluminum foil, energy consumption during production and carbon dioxide emission can be reduced, and separation and recycling at the time of disposal are facilitated, thus providing excellent environmental compatibility. Furthermore, since a metal detector can be used, quality checks such as contamination inspection of contents in various applications, particularly food applications, can be easily realized with high certainty.

  In addition to the above, the lid material of the present invention can realize a suitable heat resistance without using a large number of laminate layers, and can also realize a suitable dead hold property because the bendability of the heat-resistant coating layer is also good. Even when an overcap or the like is used, the cap can be suitably fitted (fitted), and the production efficiency is also good.

  The present invention is a lid for a sealed container 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. The resin base material is a resin base material having a puncture strength of less than 6N when pierced with a 0.5 mmR hemispherical needle at a speed of 50 mm / min, and the heat-resistant coating layer is a cellulose acetate coating agent It is the layer which consists of.

[Resin substrate]
One surface of the resin base material used in the present invention is a heat-sealable thermoplastic resin layer (hereinafter referred to as heat-sealable thermoplastic resin layer (A1)), and a 0.5 mmR hemispherical needle is pierced at a speed of 50 mm. It is a resin substrate having a puncture strength of less than 6N when punctured at / min.

  The resin base material used in the present invention has a puncture strength of less than 6N, preferably less than 5N, more preferably less than 4N when a 0.5 mmR hemispherical needle is pierced at a puncture speed of 50 mm / min. By setting the piercing strength, a suitable easy-penetrating lid material can be obtained. The lower limit of the puncture strength is not particularly limited, but it is preferably 0.5N or more because it is easy to ensure suitable breaking resistance, and is 1N or more from the viewpoint of preventing bag breakage at the time of dropping. Is more preferable.

  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. Among these, a polyolefin resin can be preferably used because it is easy to obtain suitable heat sealability and the above-mentioned puncture strength at low cost.

  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 within this range, the film shrinkage is small even when performing secondary molding such as heat molding after multilayering, and thus it is easy to maintain the appearance and to suppress warping of the medium itself, 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 within this range, due to appropriate rigidity, it is easy to improve dead hold property, mechanical strength such as pinhole resistance is excellent, 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, the sealing performance when heat sealing is also 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-based polymer includes a ring-opening polymer of a norbornene-based monomer (hereinafter referred to as “COP”), a norbornene-based copolymer obtained by copolymerizing a norbornene-based 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.

  In addition, the heat-sealable thermoplastic resin layer (A1) is essentially composed of 1-butene copolymer having 1-butene and propylene as essential components as described in JP-A-2006-213065, and propylene and ethylene. By setting it as the heat seal layer containing the copolymer which becomes a component, it can be set as an easily openable cover material.

  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, and more preferably 1.0 or less in order to impart processing suitability and packaging suitability at the time of film forming, so that a lubricant, an antiblocking agent, and an antistatic agent are appropriately added. It is preferable to do. 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 lid 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, particularly 1.0 or less in order to impart processing suitability and packaging suitability at the time of film formation. Therefore, in the resin layer corresponding to the surface layer of the multilayer film, It is preferable to add a lubricant, an antiblocking agent and 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 layer (A2) containing the acid-modified polyolefin resin. 1-5 mass parts is more preferable.

  As thickness of the resin base material used for this invention, it is preferable that it is 20-120 micrometers.

  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 1 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.

  Since the stretching temperature is affected by each resin characteristic, it is not limited, 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. .

  As the resin base material used for the lid material of the present invention, a layer other than the layer (A1) or (A2) may be appropriately used depending on the application to be used. For example, it is possible to make it easy to open by adopting a multilayer structure as described in JP-A-2004-75181 and JP-A-2008-80543.

  The resin base material used for the lid material 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 for 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 without impairing easy penetration of 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, and 0.5 to 10 μm is even 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, a coating agent having high heat resistance, easy penetration, and packaging machine properties can be preferably used from the viewpoint of forming a coat 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 when considering particularly mechanical strength, and the use of aliphatic or cycloaliphatic diisocyanate compounds when considering particularly durability and light resistance. Use is desirable.

  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 crosslinking agent is used as the crosslinking agent, the crosslinking agent is used in an amount of 5 parts by mass or more in terms of solid content with respect to 100 parts by mass of the cellulose acetate coating agent (b). 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.

[Cover material]
The lid material of the present invention is a lid material used for a sealed container, has the above heat-sealable thermoplastic resin layer (A1), and has the above acetic acid on a resin base material having a piercing strength of less than 6N. It is a lid | cover material formed from the laminated | multilayer film of the structure in which the heat-resistant coating layer (B) which consists of a cellulose-type coating agent (b) was provided. The lid material of the present invention can realize extremely high heat resistance by the simple configuration without impairing the packaging machine suitability by a packaging machine such as a cup sealer or the easy penetration of the resin base material. In addition, the surface layer does not adhere to the seal bar, and deterioration of the appearance due to generation of dirt on the seal bar, wrinkles of the seal portion, or the like can be suitably suppressed. 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 laminating a stretched substrate or the like. In addition, since it is possible to achieve easy penetration without using aluminum foil, it is possible to realize suitable design and environmental friendliness, and it is possible to check the quality with a metal detector after filling the sealed container with the contents It becomes. Furthermore, since it is easy to obtain a suitable dead hold property, a suitable workability can be realized even when an overcap is used.

  The thickness of the lid material of the present invention is preferably 15 to 150 μm because heat sealability, handling property, dead hold property and the like are favorable, and more preferably 20 to 120 μm.

  The lid material of the present invention is prepared by adjusting the cellulose acetate-based coating agent (b) to an arbitrary resin concentration, then applying it on the resin base material, drying it, and performing a curing treatment such as thermosetting as necessary. After obtaining the laminated film, it can be produced by processing by punching or the like according to the use mode. 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 for volatilizing the medium contained in the coating agent after coating the cellulose acetate-based coating agent (b) on the resin substrate is not particularly limited. For example, using a dryer The method of drying is common. The drying temperature may be a temperature that can volatilize the medium and does not adversely affect the substrate.

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

  The laminated film used in the present invention can be made into a substantially unstretched laminated film by the above-described manufacturing method, so that secondary forming such as deep drawing by vacuum forming, foil pressing, embossing, etc. is also possible. It becomes.

  The lid material of the present invention may be provided with a decorative layer such as characters, figures, symbols, etc. 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.

  The lid material of the present invention preferably has a piercing strength of 7N or less, more preferably 6N or less, and more preferably 5N or less when piercing a 0.5 mmR hemispherical needle at a piercing speed of 50 mm / min. Is more preferable. The lower limit is not particularly limited, but is preferably 0.5N or more because it is easy to ensure a suitable breaking resistance, and more preferably 1N or more from the viewpoint of preventing bag breakage during dropping. When the puncture strength is within this range, it is easy to penetrate and it is possible to prevent tearing and tearing from the portion after the opening is formed. The liquid content can be taken out from the opening, and the outflow of the content can be suppressed to some extent even when the container falls.

  The lid material of the present invention can be applied to various sealed containers. For example, a lid material for sealing a plastic cup opening filled with beverages such as juice and coffee, and a plastic lid for sealing these cup openings. Opening lid provided in the lid, lid for sealing the container such as powdered glass such as powdered milk and instant coffee, etc., lid for sealing the opening provided in a part of the pack filled with beverage It can be used in various modes that require easy penetration through straws or fingers.

  As a method of sealing various filling containers with the lid material, the lid material of the present invention can be sealed by thermal bonding to the opening of the filling container. For example, in a plastic cup filled with beverages such as juice and coffee, when sealing a circular upper opening, a method of heat-sealing the lid material punched into the shape of the opening, Depending on the state of the filling container to be used, such as a method of installing a sheet-like lid material of the present invention in the upper opening of a plurality of cups and punching it into the shape of the opening together with heat sealing, etc. What is necessary is just to seal in the aspect.

  With the above configuration, the lid material of the present invention can effectively improve the surface heat resistance while maintaining good easy penetration. For this reason, it is advantageous in reducing the manufacturing cost by shortening the sealing time. Moreover, since it is possible to realize suitable easy penetration and suitability for packaging machinery without using an aluminum foil or a laminate layer, it is excellent in printability and environmental compatibility, and a metal detector can also be applied. Since it can be used, quality checks such as contamination inspection of contents in various applications, particularly food applications, can be easily realized with high certainty. Furthermore, since a large number of laminate layers are not required and the heat-resistant coating layer has good folding suitability, it can be applied to various shapes, and caps can be suitably fitted even when an overcap or the like is used. . Such a lid material of the present invention can be suitably applied to various aspects such as a lid material for sealing a beverage cup or a beverage pack, a lid material for a container for powder-preference items.

  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.

[Puncture strength test]
According to the test method defined in the Food Sanitation Law, the resin base material used in the examples and the film obtained in the comparative example was pierced with a 0.5 mmR hemispherical needle, and the angle was from the vertical direction (90 °). The puncture strength when pierced at a puncture speed of 50 mm / min was measured.
○: Puncture strength is less than 6N.
X: Puncture strength is 6N or more.

[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.
Δ: Partial peeling of coat layer.
X: There exists peeling of a coating layer.

[Packaging machinery proper evaluation]
The film obtained in the examples and comparative examples, as a lid material punched with 75 mmφ having a tab portion (13 mm), in each cup container (APET, PP, PE, PS, thickness 700 μm) from 140 ° C. to 190 ° C., Sealing was adjusted for optimum heat seal strength at a seal time of 1 second and a seal pressure of 100 MPa. Whether a film was taken on the seal head (heat source) was evaluated as follows.
○: Not taken by the seal head in all temperature zones △: Taken by the seal head only in the temperature zone of 190 ° C ×: Taken by the seal head in the temperature zone of 180 ° C or less

[Opening strength]
The opening strength after heat sealing was evaluated as follows. The tab portion was pinched with a chuck, and the strength was measured with a tensile tester.
○: 5N / 1 cup or more ×: Less than 5N / 1 cup

Moreover, about the opening strength after heat-sealing, it evaluated by the following. The tab part was pinched with a chuck, and the strength was measured with a tensile tester at an opening angle of 45 °.
○: 5N / 1 cup or more ×: Less than 5N / 1 cup

[Straw piercing evaluation]
The film obtained in the above Example and Comparative Example was punched with 75 mmφ having a tab portion (13 mm), and a cup container (APET or PP, thickness 700 μm) was 140 ° C. to 190 ° C., and the sealing time was 1 second. The seal was adjusted and sealed so that the optimum heat seal strength was obtained at a seal pressure of 100 MPa. In accordance with the test method stipulated in the Food Sanitation Law, a commercially available straw (tip angle 45 degrees, diameter 4.84 mm) is used instead of the measuring needle, and the piercing angle is vertical (90 degrees). ).
○: Puncture strength is less than 9N.
X: Puncture strength is 9N or more.

(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 of Cellulose Acetate 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 of Cellulose Acetate 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 resin base material made of a co-extruded multilayer film having a two-layer structure and a thickness of each layer of 45 μm / 5 μm (total 50 μm) was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. The film was applied so as to have a thickness of 2 μm, and the heat-resistant olefin-based multilayer film of Example 1 was produced.

(Example 2)
A heat-resistant olefin-based multilayer 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)
A heat-resistant olefin-based multilayer 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-3) obtained in Preparation Example 2. Created.

Example 4
As resin for resin layer (A1), adhesive acid-modified polyethylene [manufactured by Tosoh Corporation, density: 0.940 g / cm ³ , MFR: 28 g / 10 min (190 ° C., 21.18 N) “MX28”; It is called “EVA”. ] Was used.
Example 1 The acid-modified olefin resin of the resin layer (A2) was replaced with an ethylene-methyl acrylate copolymer (MA content 12%, density: 0.933 g / cm ³ ; hereinafter referred to as “MA2”). A resin substrate comprising a coextruded multilayer film in which co-melt extrusion is carried out in the same manner as described above, and the layer structure of the film is a two-layer structure of (A1) / (A2), and the thickness of each layer is 40 μm / 20 μm (total 60 μm) The material was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. Coating was performed so that the thickness was 0.5 μm, and a heat-resistant olefin-based multilayer film of Example 4 was produced.

(Example 5)
As resin for the resin layer (A1), 80 parts by mass of EVA and high-density polyethylene [density: 0.960 g / cm ³ , melting point 128 ° C., MFR: 10 g / 10 min (190 ° C., 21.18 N); hereinafter, “HDPE” That's it. 20 parts by mass of a resin mixture was used.
The acid-modified olefin resin of the resin layer (A2) is an ethylene-methyl acrylate-maleic anhydride copolymer [density: 1.00 g / cm ³ , copolymer content 15%; hereinafter referred to as “MA3”] 50 mass And 50 parts by mass of a resin mixture of Homopropylene (MFR: 8 g / 10 min (230 ° C., 21.18 N), melting point: 160 ° C .; hereinafter referred to as “HOPP”).
Co-extrusion extrusion was performed in the same manner as in Example 1, and from a co-extruded multilayer film having a two-layer configuration of (A1) / (A2) and a thickness of each layer of 50 μm / 10 μm (total 60 μm) A resin base material was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. The film was applied to a thickness of 1 μm to produce the heat-resistant olefin-based multilayer film of Example 5.

(Example 6)
As resin for resin layer (A1), 90 parts by mass of HDPE and linear low density polyethylene [density: 0.900 g / cm ³ , melting point 85 ° C., MFR: 5 g / 10 min (190 ° C., 21.18 N); "LLDPE". 10 parts by mass of a resin mixture was used.
For the resin layer (A2), a resin mixture of 50 parts by mass of MA1 and 50 parts by mass of COPP was used.
Co-extrusion extrusion was performed in the same manner as in Example 1, and from a co-extruded multilayer film having a two-layer configuration of (A1) / (A2) and a thickness of each layer of 40 μm / 10 μm (total 50 μm) A resin base material was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. Coating was performed so that the thickness was 1 μm, and a heat-resistant olefin-based multilayer film of Example 6 was produced.

(Example 7)
As the resin for the resin layer (A1), COPP was used, and for the resin layer (A2), a resin mixture of 20 parts by mass of MA1 and 80 parts by mass of COPP was used.
Co-extrusion extrusion was carried out in the same manner as in Example 1, and from a co-extruded multilayer film in which the layer structure of the film was a two-layer structure of (A1) / (A2) and the thickness of each layer was 45 μm / 5 μm (total 50 μm) A resin base material was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. The film was applied so as to have a thickness of 1 μm, and a heat-resistant olefin-based multilayer film of Example 7 was produced.

(Example 8)
Resin layer (A2) is made of acrylic acid-modified resin and ethylene- (meth) acrylic acid copolymer [density: 0.940 g / cm ³ , acid modification rate 12%; hereinafter referred to as “MA4”] 50 parts by mass and COPP 50 The mixed resin product with the parts by mass was replaced by co-melt extrusion in the same manner as in Example 1, and the film layer structure was a two-layer structure (A1) / (A2), and the thickness of each layer was 40 μm / 10 μm A resin substrate made of a coextruded multilayer film having a total of 50 μm) was obtained. Using the obtained resin base material, a heat-resistant olefin-based multilayer film of Example 8 was produced in the same manner as in Example 7.

Example 9
The resin layer (A2) is replaced with a mixed resin product of 50 parts by mass of MA1 and 50 parts by mass of COPP, and co-melt extrusion is performed in the same manner as in Example 1 so that the layer structure of the film is (A1) / (A2). The resin base material which consists of a coextrusion multilayer film whose structure is 40 micrometers / 20 micrometers (total 60 micrometers) in the thickness of each layer was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. Coating was performed so that the thickness was 5 μm, and a heat-resistant olefin-based multilayer film of Example 9 was produced.

(Example 10)
As the resin for the resin layer (A1), an amorphous polyethylene terephthalate copolymer (PETG6763 manufactured by Eastman Chemical Japan Co., Ltd .; hereinafter referred to as PETG) was used.
The resin layer (A2) was replaced with a mixed resin product of 60 parts by mass of MA3 and 40 parts by mass of COPP, and co-melt extrusion was carried out in the same manner as in Example 1 so that the layer structure of the film was (A1) / (A2). The resin base material which consists of a co-extrusion multilayer film whose thickness of each layer is 60 micrometers / 10 micrometers (total 70 micrometers) by the structure was obtained. After the corona discharge treatment is performed so that the wetting tension is 40 mN / m on the surface of the (A2) layer of the resin base material, the cellulose acetate coating agent (b-1) obtained in Preparation Example 1 is dried. Coating was performed so that the thickness was 1 μm, and a heat-resistant olefin-based multilayer film of Example 10 was produced.

(Comparative Example 1)
After applying a urethane adhesive to the treated surface side of 12 μm of biaxially stretched polyester so as to be ² g / m ² , 50 μm of PP film (manufactured by DIFAREN E3800T DIC) was dry laminated to obtain a laminate film. Because heat-resistant biaxially stretched polyester is used, the packaging machine suitability evaluation is not a film on the seal bar in all temperature zones (○), and the puncture strength is 7.5 N (×) In addition, there was no straw piercing property (x), and the opening strength when using a PP container was ○.

(Comparative Example 2)
Evaluation was carried out without applying a cellulose acetate-based coating agent to the co-pressed multi-layered multilayer film prepared in Example 1.
In the packaging machine suitability evaluation, a film is formed on the seal bar at a temperature range of 150 ° C or higher, (×), the piercing strength is 4N (○), and there is a straw piercing property (○). The opening strength when used was ○.

(Comparative Example 3)
After applying urethane adhesive to the treated surface side of aluminum foil 9 μm to 2 g / m ² , PP film 50 μm (manufactured by DIFAREN E3800T DIC) was dry laminated to obtain a laminate film as in Comparative Example 1. . Due to the use of aluminum foil as the base material, the packaging machine suitability is evaluated as a film on the seal bar in all temperature zones (○), the piercing strength is 3N (○), and there is a straw piercing property ( ○), it was confirmed that the opening strength when using a PP container was ○, but there was no visibility, and naturally a metal detector could not be used.

  As is apparent from the above table, the laminated films of the present invention of Examples 1 to 10 were excellent in surface heat resistance, had suitable packaging machine suitability, and had a low puncture strength. On the other hand, the laminated films of Comparative Examples 1, 2, and 3 that do not have a heat-resistant coating layer have too high puncture strength, low heat resistance, and poor packaging machine suitability at high heat seal temperatures, Since it was used, it was inferior in visibility.

Claims (5)

A lid for a sealed container,
It has a heat-resistant coating layer on the resin substrate,
The surface having the heat-resistant coating layer of the resin substrate is composed of a heat-sealable thermoplastic resin layer on the other surface.
The resin base material is a resin base material having a piercing strength of less than 6N when piercing a 0.5 mmR hemispherical needle at a piercing speed of 50 mm / min,
A lid material, wherein the heat-resistant coating layer is a layer made of a cellulose acetate-based coating agent.   The lid material according to claim 1, wherein the resin base material includes a heat-sealable thermoplastic resin layer.   The cover material according to claim 1, wherein the surface layer of the resin base material having the heat-resistant coating layer is a layer containing an acid-modified olefin resin.   The said cellulose acetate type coating agent contains a cellulose acetate, a crosslinking agent, and an organic solvent, The acetylation degree of the said cellulose acetate is 40 to 70%, The cover material in any one of Claims 1-3.   The lid according to any one of claims 1 to 4, wherein the lid has a thickness of 15 to 150 µm.