JP2006181797A - Re-sealable coextrusion multilayered film and re-sealable laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a re-sealable coextrusion multilayered film having oxygen gas barrier properties and easy opening properties and having good adhesiveness even under a high temperature and high pressure condition, and a re-sealable laminated film. <P>SOLUTION: The re-sealable coextrusion multilayered film is constituted by successively laminating an oxygen gas barrier resin layer (A) containing a saponified material of an ethylene/vinyl alcohol copolymer or a polyamide resin, a pressure-sensitive adhesive resin layer (B), which contains an amorphous olefinic resin (b1) and/or a hydrogenated material (b2) of a block copolymer having a styrene block and a diene block, and a heat-sealing resin layer (C) containing an olefinic resin. The re-sealable laminated film is constituted by laminating a base material on the re-sealable coextrusion multilayered film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resealable coextruded multilayer film having oxygen gas barrier properties and easy opening properties, and capable of resealing even under high temperature and high humidity and capable of resealing.

  A conventional multilayer film that can be resealed is a flexible packaging material comprising a base layer, a pressure-sensitive adhesive layer adjacent to the base layer, and a skin layer covering the pressure-sensitive adhesive layer. Each surface has a coefficient of friction that allows the material to be machined in the packaging machine, which material is sealed to itself by the sealing jaws of the packaging machine and remains closed during normal handling For initial opening, a package with a seal that can be easily separated by hand can be formed. Flexible packaging material that is exposed at the surface of the sealing area so that the packaging material can be sealed against itself in the area of the sealing by the application of hand pressure only to reclose the package Known (e.g., see Patent Document 1.).

  In Patent Document 1, there is a description that a coextrusion method (coextrusion method) in which a base layer is coextruded with a pressure-sensitive adhesive layer and a skin layer can be adopted as a method for producing a flexible packaging material. Are exemplified by a multilayer film obtained by an extrusion lamination method in which a pressure-sensitive adhesive layer and a skin layer are coextruded on a base layer, for example, a styrene / isoprene / styrene layer on a base layer made of a poly (ethylene terephthalate) film. Multi-layer film having easy-openability and resealability obtained by extrusion lamination method such as co-extrusion of pressure-sensitive adhesive layer containing block copolymer and aliphatic petroleum hydrocarbon resin and skin layer made of polystyrene A coextruded multilayer film having oxygen gas barrier properties, easy-opening properties and resealability produced by a coextrusion method, and a substrate laminated on the coextruded multilayer film. No or suggestion described specifically showing preferred layer configuration of the re-sealable laminated film was collected.

  Under such circumstances, due to recent environmental considerations and cost reductions, the sealant film itself retains the function of having an oxygen gas barrier property, has an appropriate easy-opening strength, and is excellent in high temperature and high humidity. A coextruded multilayer film exhibiting sealing properties and a laminate film using the coextruded multilayer film are desired.

Japanese National Publication No. 04-502588 (page 2-3)

  An object of the present invention is to provide a coextruded multilayer film having oxygen gas barrier properties and appropriate easy opening strength, and excellent resealability even under high temperature and high humidity, and a substrate on the resealable multilayer film. Is to provide a resealable laminate film that is laminated.

  As a result of intensive studies, the present inventors have found that the oxygen gas barrier resin layer (A), the pressure-sensitive adhesive resin layer (B), and the heat seal resin layer (C) are (A) / (B) / (C). Resealable coextruded multilayer film laminated in order by coextrusion method, resin layer comprising saponified ethylene-vinyl alcohol copolymer or polyamide resin as oxygen gas barrier resin layer (A) And a pressure sensitive resin layer (B) containing an amorphous olefin resin (b1) and / or a hydrogenated block copolymer (b2) having a styrene block and a diene block (b2) And select a resin layer containing a heat-sealable olefin resin as the heat-seal resin layer (C), and combine them so that they are in the order of (A) / (B) / (C) The laminated coextruded multilayer film and the laminated film in which the base material is laminated on the oxygen gas barrier resin layer (A) of the coextruded multilayer film are bonded to the oxygen gas barrier resin layer (A) by pressure-sensitive adhesion. Since the interlayer adhesive strength of the resin layer (B) is appropriate and lower than the interlayer adhesive strength of the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C), the heat seal resin layer (C) and this heat The sealing resin layer (C) and the heat-sealable thermoplastic resin layer may be heat-sealed [the heat-sealing of the heat-sealing resin layer (C) may be used. ], The heat seal resin layer (C) and the pressure sensitive adhesive resin layer (B) are broken and the pressure sensitive adhesive resin layer (B) and the oxygen gas barrier resin layer (A) are separated. The adhesive resin layer (B) is exposed in an adhesive state that can be resealed in the heat seal portion, and the reseal strength when repeated opening and resealing is high even under high temperature and high humidity, oxygen gas via The present invention has been completed by finding that the film is suitable as a resealable film having good properties and easy-openability.

  That is, the present invention relates to an oxygen gas barrier resin layer (A) comprising a saponified ethylene-vinyl alcohol copolymer or a polyamide resin, an amorphous olefin resin (b1) and / or a styrene block. And a pressure-sensitive adhesive resin layer (B) containing a hydrogenated block copolymer (b2) having a diene block, and a heat seal resin layer (C) containing an olefin resin capable of heat sealing And (A) / (B) / (C) are laminated by the coextrusion method in order to provide a resealable coextruded multilayer film.

  The present invention also provides a resealable laminate film, wherein a base material is laminated on the oxygen gas barrier resin layer (A) of the resealable coextruded multilayer film.

  The resealable coextrusion multilayer film and resealable laminate film of the present invention both have an oxygen gas barrier property and appropriate easy-opening strength, and can maintain good resealability. Play.

  In the resealable coextruded multilayer film and resealable laminate film of the present invention, the resin layers (A) to (C) are laminated by a coextrusion method in the order of (A) / (B) / (C). Therefore, the heat seal resin layer (C) and the heat seal resin layer (C) and the heat-sealable thermoplastic resin layer may be heat sealed [a heat seal of the heat seal resin layer (C) may be used. ], When peeled off, the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) are broken and the gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) are separated from each other. The pressure-sensitive adhesive resin layer (B) is a coextruded multilayer film that is exposed in an adhesive state that can be resealed on the surface of the heat seal region.

  The oxygen gas barrier resin layer (A) in the resealable coextruded multilayer film and resealable laminate film of the present invention contains a saponified ethylene-vinyl alcohol copolymer or a polyamide resin as a main component. The resin layer may be a single layer resin layer or a multilayer resin layer.

  Saponified product of ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH). ] Is preferably an ethylene-derived component content of 30 to 60 mol% and a saponification degree of 95% or more because it is excellent in moldability and oxygen gas barrier properties, and in particular, oxygen gas barrier properties are reduced due to moisture absorption. Since it is comparatively few, the thing of 20-50 mol% of ethylene origin component content is more preferable, and the thing of 27-48 mol% of ethylene origin component content is the most preferable. Examples of the polyamide-based resin include nylon 6, nylon 66, nylon 6/66, nylon 6/12, and aromatic nylon.

  Further, if necessary, the oxygen gas barrier resin layer (A) includes an antifogging agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a release agent, and an ultraviolet ray. You may add components, such as an absorber and a coloring agent, in the range which does not impair the objective of this invention.

  The pressure-sensitive adhesive resin layer (B) in the resealable coextruded multilayer film and resealable laminate film of the present invention is an amorphous olefin resin (b1) and / or a block having a styrene block and a diene block A resin layer containing the copolymer hydrogenated product (b2) may be used, but since it is more easily opened and resealable, it further contains a tackifier (b3). A resin layer comprising an amorphous olefin resin (b1), a hydrogenated block copolymer (b2) having a styrene block and a diene block, and a tackifier (b3). Most preferably it is.

  The amorphous olefin-based resin (b1) is not particularly limited, and examples thereof generally include those having an α-olefin-derived component content of 3 or more carbon atoms of 50 mol% or more. The content of 3 to 20 α-olefin-derived component is preferably 50 mol% or more, more preferably 3 to 12 α-olefin-derived component content of 80 mol% or more, and carbon atoms. The content of the α-olefin-derived component of 3 to 4 is most preferably 80 mol% or more.

  Further, as the amorphous olefin resin (b1), for example, even if it is a homopolymer of an α-olefin having 3 or more carbon atoms, two or more α-olefins having 3 or more carbon atoms are used. It may be a copolymer, a copolymer of an α-olefin having 3 or more carbon atoms and another monomer, or a mixture thereof.

  Examples of the amorphous olefin resin (b1) include homopolymers such as amorphous polypropylene and amorphous poly-1-butene, 50 mol% or more of 1-butene and other α-olefins (for example, , Propylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-dexene, etc.), 50 mol% or more of propylene and other α-olefins (for example, 1 -Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-dexene, etc.), and specific examples include amorphous propylene homopolymers. An amorphous 1-butene homopolymer, an amorphous propylene-1-butene copolymer having a propylene-derived component content of 50 mol% or more, and an amorphous material having a 1-butene-derived component content of more than 50 mol% 1-butene -A propylene copolymer, the amorphous propylene-1-butene copolymer in which the total content rate of a propylene origin component and a 1-butene origin component exceeds 80 mol%, etc. are mentioned.

  The number average molecular weight of the amorphous olefin resin (b1) is preferably 100,000 to 500,000. Further, when the amorphous olefin resin (b1) is a copolymer, it may be either a random copolymer or a block copolymer, but a random copolymer is preferred.

  Examples of the commercially available amorphous olefin resin having a content of 3 to 4 carbon atom-derived α-olefin that can be preferably used as the amorphous olefin resin (b1) are 80 mol% or more. Huntsman's "Letax", Sun Allomer's "Cataloy", Ube Lexelen's "Ubetak", Ube Industries' "CAP", Sumitomo Chemical Co., Ltd.'s "Tufselen", and the like.

  In the present invention, the amorphous property of the amorphous olefin resin (b1) is measured using a differential scanning calorimeter (DSC) with a sample of 5 mg at a temperature increase rate of 10 ° C./min from 20 to 230 ° C. When melting, no melting peak is observed, and the heat of fusion of the maximum peak in the endothermic curve is 0.7 J / g or less.

  The amorphous olefin-based resin (b1) has a large amount of low molecular weight and is sticky or resin pellets tend to adhere to each other. There is a problem in raw material handling, such as adhesion of oil is likely to occur, and accurate formulation is difficult, but in order to improve raw material handling, it is derived from other olefinic resins, for example, α-olefins having 3 or more carbon atoms Olefin resin (b4) other than the amorphous olefin resin (b1) having a component content of 50 mol% or more [hereinafter abbreviated as other olefin resin (b4). ] Are preferably used in combination. As a method of using the amorphous olefin resin (b1) and the other olefin resin (b4) in combination, the amorphous olefin resin (b1) and the other olefin resin (b4) are mixed with a twin screw extruder or the like. It is preferable to heat knead and pelletize in advance. When the amorphous olefin resin (b1) and other olefin resin (b4) are used in combination, the weight ratio (b1) / (b4) is preferably 95/5 to 60/40, and 90/10 to 70/30. Is more preferable.

  The other olefin-based resin (b4) may be an olefin-based resin other than the amorphous olefin-based resin (b1) in which the content of the α-olefin-derived component having 3 or more carbon atoms is 50 mol% or more. For example, propylene-based resin, 1-butene-based resin, trimethylpentene-1 (TPX) and the like can be mentioned. Among them, propylene-based resin is preferable because it has heat resistance, a high melting point, and is easily available.

  Examples of the hydrogenated product (b2) of the block copolymer having a styrene block and a diene block include a hydrogenated product (HSBR) of a styrene-butadiene block copolymer (SB) and a styrene-butadiene-styrene block copolymer. Hydrogenated product of combination (SBS) (SEBS), hydrogenated product of styrene-isoprene-styrene block copolymer (SIS) (styrene-ethylene-propylene-styrene block copolymer, SEPS), styrene-isoprene block copolymer Examples include coal (SI) hydrogenated products, especially low odor, no appearance defects such as gels, fish eyes, fluid turbulence, etc., and continuous production for a long time and good resealability. Since a pressed film is obtained, a hydrogenated product of styrene-butadiene block copolymer (SB) (HS R), hydrogenated product of styrene-butadiene-styrene block copolymer (SBS) (SEBS), hydrogenated product of styrene-isoprene-styrene block copolymer (SIS) (styrene-ethylene-propylene-styrene block copolymer) Coalescence, SEPS) is preferred.

  The hydrogenation ratio of the hydrogenated product (b2) of the block copolymer having a styrene block and a diene block is usually 10 to 100 mol%, and preferably 30 to 100 mol%. Further, the melt index (measured at 190 ° C. in accordance with MI, JIS K-7210) is preferably 2 to 30 g / 10 minutes because flow disturbance is unlikely to occur.

  Since the pressure-sensitive adhesive resin layer (B) is a resin layer having a good balance between adhesiveness and heat resealability, a block copolymer having an amorphous olefin resin (b1), a styrene block, and a diene block is used. A resin layer containing a hydrogenated polymer (b2) is preferred, and in particular, an amorphous olefin resin (b1), a hydrogenated block copolymer (b2) having a styrene block and a diene block, and A resin layer containing the tackifier (b3) is particularly preferable. In this case, the other olefin resin (b4) can be used in combination for improving the raw material handling of the amorphous olefin resin (b1), and the weight ratio (b1) / (b4) is 95 / 5-60 / 40 is preferable and 90 / 10-70 / 30 is more preferable.

  Resin in which the pressure-sensitive adhesive resin layer (B) contains an amorphous olefin resin (b1) and, if necessary, a hydrogenated product (b2) of a block copolymer having a styrene block and a diene block. In the case of a layer, the use ratio of (b1) and (b2) is preferably such that the weight ratio (b1) / (b2) is 20/80 to 100/0. It is more preferable that the weight ratio (b1) / (b2) is 30/70 to 80/20 because the resin layer has a good balance of resealability.

  The pressure-sensitive adhesive resin layer (B) contains an amorphous olefin resin (b1), a hydrogenated block copolymer (b2) having a styrene block and a diene block, and a tackifier (b3). In the case of the resin layer, the use ratio of (b1), (b2) and (b3) is such that the weight ratio (b1) / (b2) is 20/80 to 100/0 and the weight ratio (b1 + b2 ) / (B3) is preferably a ratio of 50/50 to 98/2, and the weight ratio (b1) / (b2) is particularly favorable because the resin layer has a good balance between adhesiveness and heat resealability. ) Is 30/70 to 80/20, and the weight ratio (b1 + b2) / (b3) is more preferably 60/40 to 90/10.

  In the pressure-sensitive adhesive resin layer (B), when the amorphous olefin resin (b1) and the other olefin resin (b4) are used in combination, the amorphous olefin resin (b1) and the other olefin resin are used. The resin (b4) is preferably used after being melt-kneaded and then pelletized. The melt index (measured at 230 ° C. according to MI, JIS K-7210) of the pellets is preferably 0.1 to 30 g / 10 minutes because flow disturbance is unlikely to occur. More preferably, it is 5 to 20 g / 10 minutes.

  In the pressure-sensitive adhesive resin layer (B), the styrene block and the diene block are also used when the hydrogenated product (b2) of the block copolymer having a styrene block and a diene block and the tackifier (b3) are used in combination. The block copolymer hydrogenated product (b2) and tackifier (b3) are preferably melt-kneaded and then pelletized for use.

  Examples of the tackifier (b3) include resins having an adhesive property at room temperature made of natural resin or synthetic resin, such as natural resin rosin, polymerized rosin, hydrogenated rosin, glycerinster rosin, pentaerythritol and the like. Rosin resin; Terpene resin such as terpene, aromatic modified terpene, terpene phenol, hydrogenated terpene; Petroleum resin such as aliphatic petroleum resin, aromatic petroleum resin, hydrogenated alicyclic petroleum resin; Examples thereof include liquid polybutadiene, polyisoprene which is liquid at normal temperature, and polyisobutylene which is liquid at normal temperature, among which rosin resin, terpene resin and petroleum resin are preferable.

  Various additives such as softener, oil (mineral oil), stabilizer (antioxidant, etc.), surfactant, liquid paraffin, etc. are added to the pressure-sensitive adhesive resin layer (B) as necessary. May be.

  The heat-sealing resin layer (C) in the resealable coextruded multilayer film and resealable laminate film of the present invention may be a resin layer containing an olefin-based resin capable of heat heel, such as ethylene. Heat sealing according to the material of the heat seal part of the adherend such as a container for heat sealing the resealable coextruded multilayer film or resealable laminate film of the present invention. A possible resin may be selected as appropriate.

Examples of the ethylene resin include ethylene resins such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). Ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate -Ethylene copolymers such as maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA); and ethylene-acrylic acid Metal neutralized copolymer, ethylene-methacrylic acid copolymer Metal neutralized products and the like, among density 0.895~0.940g / cm ³ of ethylene-based resin, for example, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE ) Is preferred.

  Examples of the propylene-based resin include propylene homopolymers, copolymers of propylene and other α-olefins such as ethylene and butene, and propylene and other α-olefins such as propylene-ethylene copolymer. Polymers, propylene-1-butene copolymers and the like are preferable. As the copolymer, either a random copolymer or a block copolymer can be used, but usually a random copolymer is used. Examples of the propylene homopolymer include isotactic polypropylene, syndiotactic polypropylene, and attack polypropylene. Among these, isotactic polypropylene is preferable.

  In addition, as said olefin resin, since it is excellent in the adhesiveness of a container and a lid | cover material, stability of seal strength, etc., it is 190 degreeC in ethylene resin, and 210 in a propylene resin system based on JISK-7210. Those having an MI (melt index) measured at 0 ° C. of 2 to 80 g / 10 minutes are preferred.

  The heat seal resin layer (C) has a friction coefficient of 0.7 or less, particularly 0.5 or less, considering the processability during film formation and the packaging suitability of the filling machine. It is desirable to be. For this reason, it is preferable to add a lubricant and an antiblocking agent to the heat seal resin layer (C) as appropriate.

  Further, on the surface of the heat seal resin layer (C), low molecular weight components and the like from the amorphous olefin resin (b1) and the tackifier (b3) in the adhesive resin layer (B) are blitted over time. Precipitation) may occur, and the problem of deterioration of slipperiness and film blocking tends to occur. As a solution, it is effective to emboss the surface of the multilayer film and to add a filler to the heat seal resin layer (C). As the filler, inorganic materials such as calcium carbonate and talc are desirable because they are in a state where large irregularities are expressed on the price and surface, and a good friction coefficient can be maintained.

  Furthermore, for the heat seal resin layer (C), an anti-fogging agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a release agent, and an ultraviolet absorber, if necessary. Further, a colorant and the like may be added within a range that does not impair the object of the present invention.

  In addition, the resealable coextruded multilayer film and resealable laminate film of the present invention are formed between the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) when the heat seal portion is peeled off. Since peeling does not occur, even if additives such as lubricants and antiblocking agents are added to the heat seal resin layer (C), there is no effect on the delamination part due to the addition of lubricants and antiblocking agents. There is an advantage that the stability of reseal strength is high without lowering the adhesiveness.

  The resealable coextrusion multilayer film and resealable laminate film multilayer film of the present invention have a resin layer (adhesive resin layer) having the same composition as the heat seal resin layer (C), such as a heat seal. When a container or film having a resin layer having the same composition as that of the resin layer (C) is heat sealed and peeled off, the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) are broken. At the same time, the oxygen gas barrier resin layer (A) and the pressure sensitive adhesive resin layer (B) are separated from each other, and the pressure sensitive adhesive resin layer (B) is exposed in a resealable state on the surface of the heat seal region. Yes, as the heat seal resin layer (C), the interlayer adhesive strength with the pressure-sensitive adhesive resin layer (B) is larger than the interlayer adhesive strength between the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B). The resin layer must be It is. Therefore, the olefin resin used in the heat seal resin layer (C) is a resin that can be heat sealed according to the material of the heat seal portion of the adherend such as a container, preferably a pressure sensitive adhesive resin from the same type of resin. It is preferable to select and use a resin having a high interlayer adhesion strength with the layer (B).

  For such a heat seal resin layer (C), the oxygen gas barrier resin layer (A) contains a saponified ethylene-vinyl alcohol copolymer or a polyamide resin as pressure-sensitive adhesive, Since the interlayer adhesive strength of the pressure-sensitive adhesive resin layer (B) is appropriate and lower than the interlayer adhesive strength of the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C), the heat seal resin layer (C) When heat-sealing with a resin layer having the same composition and peeling off, the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) are easily separated.

  In the resealable coextruded multilayer film and resealable laminate film of the present invention, the interlayer adhesive strength between the oxygen gas barrier resin layer (A) and the pressure sensitive adhesive resin layer (B) is 2 to 23 N / 15 mm. And it is preferable that it is smaller than the interlayer adhesive strength of an adhesive resin layer (B) and a heat seal resin layer (C). This interlayer adhesive strength is a strength that can maintain the function as a multilayer film, and is a strength that allows relatively easy delamination, and the oxygen gas barrier resin layer (A) when the heat seal portion is peeled off There is little roughness of the delamination surface of the pressure-sensitive adhesive resin layer (B), and the reseal strength is high when opening and resealing are repeated. The interlayer adhesive strength between the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) is more preferably 2 to 18 N / 15 mm, and the pressure-sensitive adhesive resin layer (B) and the heat seal resin More preferably, it is 2 N / 15 mm or less smaller than the interlayer adhesive strength of the layer (C).

  The method for producing the resealable coextruded multilayer film of the present invention is not particularly limited as long as it is a coextrusion method. For example, it contains a saponified ethylene-vinyl alcohol copolymer or a polyamide resin. An oxygen gas barrier resin layer (A) resin, a saponified ethylene-vinyl alcohol copolymer or a polyamide resin, and, if necessary, a tackifier (b3), another olefin resin (b4) The resin for pressure-sensitive adhesive resin layer (B) containing the resin and the resin for heat sealing resin layer (C) containing the heat-sealable olefin resin are heated and melted in separate extruders. And after lamination in the order of (A) / (B) / (C) in a molten state by a known method such as a coextrusion multilayer die method or a feed block method, inflation or T-die chill Coextrusion method or the like to co-extrusion laminated molded into a film shape by Lumpur method. Further, in order to improve the adhesion of the printing ink and the suitability for lamination with the substrate, it is desirable to subject the oxygen gas barrier resin layer (A) to a surface treatment.

  Examples of the 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 sand blasting. is there.

  In the resealable coextruded multilayer film of the present invention, as a preferable combination of each resin layer, for example, an oxygen gas barrier resin layer using a saponified ethylene-vinyl alcohol copolymer or a polyamide resin, and , Hydrogenated and Adhesive of Rubber Block Copolymer Containing Amorphous Olefin Resin with 3 to 12 Carbon Alpha-Olefin-Derived Component and 80 Mol% or More, Styrene Block, and Diene Block A combination of a pressure-sensitive adhesive resin layer using an imparting agent (b3) and a propylene resin and a heat seal resin layer using an ethylene resin or a propylene resin can be mentioned. Among these, as the tackifier (b3) in the pressure-sensitive adhesive resin layer, one using at least one resin selected from the group consisting of a rosin resin, a terpene resin and a petroleum resin is particularly preferable. Moreover, what uses the random copolymer of linear low density polyethylene or a propylene, and another (alpha) -olefin as ethylene-type resin or propylene-type resin in a heat seal resin layer is preferable.

  The packaging material having resealability using the resealable coextruded multilayer film or resealable laminate film of the present invention prevents the risk of being resealed and displayed for sale after being opened. Since it can do, it is preferable that the trace at the time of opening can be distinguished easily. As a method for leaving a trace at the time of opening, it is effective to add a colorant or a filler to the pressure-sensitive adhesive resin layer (B). As the filler, inorganic materials such as calcium carbonate and talc are desirable because the price and trace state are clear.

  Further, in the production of the resealable coextruded multilayer film and resealable laminate film of the present invention, it is necessary to consider that the interlayer adhesive strength varies depending on the thickness of the resin layer. Even if the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) are used in a combination that is relatively excellent in adhesiveness, for example, in the case of a heat seal resin layer made of polyethylene resin, the thickness is 0.1. If it is as small as ˜0.5 μm, the interlayer adhesive strength with the pressure-sensitive adhesive resin layer (B) is greatly reduced.

  The thickness of the resealable coextruded multilayer film of the present invention is usually in the range of 15 to 75 μm, and preferably in the range of 25 to 65 μm. If it is this thickness, it can laminate on base materials, such as an extending | stretching base film, and can each be used suitably as lid | cover materials, such as various containers.

  In the resealable coextruded multilayer film of the present invention, the thickness of the oxygen gas barrier resin layer (A) is usually 2 to 30 μm, preferably 4 to 20 μm, and the thickness of the pressure-sensitive adhesive resin layer (B) is usually 8 -30 μm, preferably 10-20 μm, and the thickness of the heat seal resin layer (C) is usually 5-35 μm, preferably 10-30 μm. The total thickness of the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) is usually 13 to 60 μm, preferably 20 to 50 μm.

  The resealable coextruded multilayer film of the present invention can be used as it is by sealing with heat adherence to the adherend as it is, but the base material is bonded to the oxygen gas barrier resin layer (A) via an adhesive resin or an adhesive. Is preferably laminated to form a resealable laminate film. Examples of the base material include biaxially oriented polypropylene (OPP) film, biaxially oriented nylon (ONY) film, biaxially oriented polyethylene terephthalate (PET) film, aluminum (AL) foil, paper, and non-woven fabric. It is not limited to these.

  Examples of the method for laminating the resealable coextruded multilayer film and the substrate of the present invention include wet lamination, non-solvent lamination, dry lamination, extrusion lamination, thermal lamination, and the like. Examples of the dry lamination adhesive include a polyester-polyurethane adhesive and a polyether-polyurethane adhesive.

  Conventionally, foods, stationery, pharmaceuticals, medical instrument supplies, etc. that are used several times are either individually packaged or packaged in a zippered bag. In individual packaging, packaging materials and packaging processes are bulky, and there are problems in terms of environmental resources and costs. For bag-making products with a zipper, it is necessary to install a device for attaching the zipper separately on the bag-making machine, and a certain degree of rigidity is required to attach it, so a laminated film or a thick film laminated with a stretched substrate is essential And the configuration was limited.

  In addition, with regard to the remaining items after consumption of a certain amount of lightweight items, confectionery, bread, etc., the opening after opening may be tied with a rubber band to prevent dirt, dust, etc. and contamination with insects, etc. In addition, it does not need to be sealed as much as a zipper, and it only needs to be able to be resealed several times. It is costly to use such a packaging bag for such contents. This is also not preferable in terms of resource saving. In particular, when packaging confectionery bread, bread, etc., there has been a demand for a packaging material that can be easily resealed at low cost without using a binding tool so as to prevent contamination by foreign substances such as insects.

  Multi-layer films with a structure such as paper / aluminum / hot melt are used for the lids of instant food containers such as ramen cups. This structure is easy to open. Using the function and plastic deformation characteristics of aluminum, keep the lid turned up when pouring hot water, and keep the lid closed by folding the handle part of the lid during cooking time. Because. However, when thin aluminum is used or in the case of a film with the aluminum removed, the plastic deformability cannot be maintained and the original state may not be restored. Is closed. Furthermore, there is a strong desire to suppress the use of aluminum for reasons such as the recent reduction of environmental impact and separation and collection, as well as the inspection of the contents with X-rays and the like to prevent foreign matter contamination and the use of defect detectors. . However, there is no material having plastic deformation performance equivalent to that of aluminum, and there are few materials that can easily maintain a resealed state during cooking. Furthermore, for the purpose of reducing the number of processing steps, a multilayer film that satisfies the above requirements has been desired. During cooking and heating under the above use conditions, the film is exposed to high temperature and high humidity.

  When an amorphous olefin-based resin having a content of an α-olefin having 3 to 12 carbon atoms of the present invention having a content of 80 mol% or more is used as a cover material, the heat seal resin layer (C) of the cover material, By overlapping and heat-sealing the heat-seal resin layer of a container filled with an article such as food, a resealable packaging container having airtightness and practical strength can be obtained. The resulting resealable packaging container is exposed to the surface in a state where the pressure-sensitive adhesive resin layer (B) can be resealed on the peeled surface after opening, and is resealed only by pressure-sensitive adhesion by hand (reseal) Is possible. In addition, when pouring hot water into an instant food container such as a ramen cup and capping the container again during cooking time, the container is kept at high temperature and high humidity, but the lid material using the multilayer film of the present invention Is excellent in heat-sealing property, so that there is little decrease in resealing strength under high temperature and high humidity, and the lid does not open. Therefore, it is possible to keep the lid closed during cooking time without using a tack seal or the like when the container is covered again, and the plastic deformation performance of aluminum becomes unnecessary. The dealuminated film, which has long been requested, can be made, reducing the number of processing steps and contributing to the reduction of environmental burden.

  Examples of the container used for such a resealable packaging container include cups and trays produced by a molding method such as injection molding, vacuum molding, and pressure molding of propylene-based resin, and further, olefin such as polyethylene on paper. Examples thereof include a paper cup and a paper tray formed by laminating a series resin. These containers have a heat seal portion with the lid material, for example, a bowl-shaped heat seal portion, and select the type of heat seal resin of the lid material according to the type of resin in this portion, and seal The strength can be adjusted.

  As a container using a lid material made of the resealable coextruded multilayer film or resealable laminate film of the present invention, for example, a propylene-based resin or the like is formed by a molding method such as injection molding, vacuum molding or pressure molding. Examples thereof include manufactured cups and trays, and paper cups and paper trays formed by laminating olefinic resins such as polyethylene on paper. These containers can adjust the seal strength by selecting the type of heat seal resin according to the type of resin in the heat seal portion with the lid.

  Furthermore, as a preferable use in using the resealable coextruded multilayer film or resealable laminate film of the present invention, a lightweight food, stationery, cosmetic or pharmaceutical is filled in a bag and packaged. . Numbers such as instant noodle containers or lids, breads, confectionery breads, snacks, chocolate confectionery, delicacy bags or lids, processed meat bags or lids such as sliced ham, wet tissue, sweat paper, fragrance, disposable diapers, etc. Examples include lids and bags for cosmetics and sanitary products that are packaged in individual units and opened and used each time, and lids and bags for pharmaceuticals such as ship medicines, emergency bandages, and throat candy. In these applications, it is not intentionally exposed to high temperatures, but it is assumed that it will become hot when left in a car in the summer or when it is stored in a warehouse, so it has excellent heat resealability. The resealable coextruded multilayer film and resealable laminate film of the invention can be suitably used for container lids and bags.

Next, the present invention will be described in more detail with reference to examples and comparative examples.
Example 1
As a resin for the oxygen gas barrier resin layer (A), a saponified ethylene-vinyl alcohol copolymer (EVOH: ethylene-derived component content 32 mol%) is used, and as a resin for the pressure-sensitive adhesive resin layer (B), Crystalline propylene-based resin [Ubetack UT2780 manufactured by Ube Lexelen Co., Ltd., propylene-derived component content of 50 mol% or more] 80 parts by weight, density 0.90 g / cm ³ and propylene-ethylene of ethylene-derived component content 3% by weight A pellet (1) obtained by melt-kneading 20 parts by weight of a copolymer (COPP) with a twin screw extruder and pelletized, and a 1,2-bond portion of a styrene-butadiene-styrene block copolymer (SBS) are selectively used. Hydrogenated to 40% by mole of selected hydrogenated product [styrene-butadiene-butylene-styrene block copolymer (SBBS)] 7 29.5 parts by weight and petroleum resin (Arakawa Chemical Co., Ltd. hydrogenated petroleum resin, Alcon P-125) and 0.5 parts by weight of phenolic antioxidant are melt-kneaded with a twin screw extruder to form pellets. Using a resin mixture (12) obtained by dry blending the pellets (2) with a mixing ratio (1) / (2) of the pellets (1) and (2) of 50/50, a heat seal resin layer ( C) As a resin for resin, erucic acid amide (lubricant) and natural silica (anti-blocking agent) were added to propylene-ethylene copolymer (COPP) having a density of 0.90 g / cm ³ and an ethylene-derived component content of 3% by weight. Using the resin mixture (3) added and mixed in such a ratio that the amide concentration is 1000 ppm and the natural silica concentration is 2000 ppm, (A) layer extruder (caliber 50 mm), (B) layer extruder (caliber 50 mm) (C) A layer extruder (40 mm in diameter) and a T-die / chill roll co-extrusion multilayer film production apparatus having a feed block are respectively supplied to each extruder, temperature 200 to 230 ° C., feed block and T die temperature Co-melt extrusion is performed under the condition of 270 ° C., and the A / B / C three-layer structure has an average thickness of 5 μm / 15 μm / 20 μm and an overall thickness of 40 μm. A resealable coextruded multilayer film (X1) having a friction coefficient of 0.6 was obtained.

  The interlayer adhesive strength of the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) of the obtained resealable coextruded multilayer film (X1) is 5 N / 15 mm, and the pressure-sensitive adhesive resin layer (B) The interlayer adhesive strength of the heat seal resin layer (C) was 25 N / 15 mm. The surface of the oxygen gas barrier resin layer (A) was subjected to corona treatment.

  In addition, when the amorphous propylene-based resin Ubetak UT2780 5 mg was used and measured at a temperature increase rate of 10 ° C./min from 20 ° C. to 230 ° C., no melting peak was observed, and the heat of fusion of the maximum peak in the endothermic curve was 0. 0.7 J / g or less.

  Next, a biaxially stretched polyethylene terephthalate film substrate (thickness 12 μm) was bonded to the oxygen gas barrier resin layer (A) side of the obtained resealable coextruded multilayer film (X1) by dry lamination, and resealed. A stop laminate film (Y1) was obtained. At this time, a two-component curable adhesive (polyester adhesive LX63F and a curing agent KP90) manufactured by Dainippon Ink & Chemicals, Inc. was used as an adhesive for dry lamination.

  This resealable laminate film (Y1) has a heat-sealing resin layer (C) and a pressure-sensitive adhesive resin layer (B) when the heat-sealing resin layer (C) is heat-sealed with a resin layer having the same composition and peeled off. ) Is broken and the pressure-sensitive adhesive resin layer (B) and the oxygen gas barrier resin layer (A) are separated from each other so that the pressure-sensitive adhesive resin layer (B) can be resealed in the heat seal region. It was an exposed laminate film.

  The obtained resealable laminate film (Y1) is used as a lid material, and the heel portion of a round cup container having a heel with an outer shape of 70 mm and a width of 5 mm made of the material shown in Table 1 below is shown in Table 1 below. After heat sealing under heat sealing conditions (sealing temperature, sealing time, sealing pressure), the sealing strength was measured. Moreover, the opening feeling at the time of opening was evaluated. Furthermore, hot water of 95 ° C is put into the opened container, and the lid part of the container is pressure-bonded again with a finger, and then left as it is for 5 minutes, and the sealing strength (resealing strength) after being left is determined. It was measured. The results are shown in Table 2.

  The feeling of opening is when the lid is actually peeled from the container and the force required for peeling is constant and smooth peeling is easy, and the force required for peeling is not constant, and peeling is not smooth. It evaluated as x.

Example 2
As a resin for the oxygen gas barrier resin layer (A), a saponified ethylene-vinyl alcohol copolymer (EVOH: ethylene-derived component content 32 mol%) is used, and as a resin for the pressure-sensitive adhesive resin layer (B), A crystalline propylene-based resin (Tufsen T3712 manufactured by Sumitomo Chemical Co., Ltd., propylene-derived component content of 50 mol% or more) is used as a heat seal resin (C) resin with a density of 0.90 g / cm ³ and an ethylene-derived component Add erucic acid amide (lubricant) and natural silica (anti-blocking agent) to propylene-ethylene copolymer (COPP) with a content of 3% by weight at a ratio of erucic acid amide concentration of 1000 ppm and natural silica concentration of 2000 ppm. (A) Extruder for layer (caliber 50 mm), (B) Extruder for layer (caliber 50 mm), (C) To each extruder of a co-extruded multilayer film manufacturing apparatus of T die / chill roll method having a feed block (diameter 40 mm) and a feed block, conditions of temperature 200-230 ° C., feed block and T die temperature 250 ° C. In the three-layer configuration of A / B / C, the average thickness of each layer is 5 μm / 15 μm / 20 μm, the total thickness is 40 μm, and the coefficient of friction on the surface of the heat seal resin layer (C) is A resealable coextruded multilayer film (X2) of 0.6 was obtained.

  The interlayer adhesive strength of the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) of the obtained resealable coextruded multilayer film (X2) is 3 N / 15 mm, and the pressure-sensitive adhesive resin layer (B) The interlayer adhesive strength of the heat seal resin layer (C) was 28 N / 15 mm. The surface of the oxygen gas barrier resin layer (A) was subjected to corona treatment.

  In addition, when the amorphous propylene-based resin Tufsen T3712 5 mg was used and measured at a temperature increase rate of 10 ° C./min from 20 ° C. to 230 ° C., no melting peak was observed, and the heat of fusion of the maximum peak in the endothermic curve was 0. 0.7 J / g or less.

  Next, a biaxially stretched polyethylene terephthalate film substrate (thickness 12 μm) was bonded to the oxygen gas barrier resin layer (A) side of the obtained resealable coextruded multilayer film (X2) by dry lamination, and resealed. A stop laminate film (Y2) was obtained. At this time, a two-component curable adhesive (polyester adhesive LX63F and a curing agent KP90) manufactured by Dainippon Ink & Chemicals, Inc. was used as an adhesive for dry lamination.

  When the heat-sealing resin layer (C) and the resin layer having the same composition are heat-sealed and peeled off, the resealable laminate film (Y2) has a heat-sealing resin layer (C) and a pressure-sensitive adhesive resin layer (B). ) Is broken and the pressure-sensitive adhesive resin layer (B) and the oxygen gas barrier resin layer (A) are separated from each other so that the pressure-sensitive adhesive resin layer (B) can be resealed in the heat seal region. It was an exposed laminate film.

Except that the obtained resealable laminate film (Y2) was used as a lid material, measurement of seal strength, evaluation of opening feeling when opened, and measurement of reseal strength were performed in the same manner as in Example 1. Was done. The results are shown in Table 2.
Example 3
6 nylon [1022B manufactured by Ube Industries, Ltd.] is used as the resin for the oxygen gas barrier resin layer (A), and an amorphous propylene resin [manufactured by Sumitomo Chemical Co., Ltd.] is used as the resin for the pressure-sensitive adhesive resin layer (B). Hydrogenation rate obtained by selectively hydrogenating 1,2-bonded portion of pellet (1) of Tuffsen T3712, propylene-derived component content of 50 mol% or more and styrene-butadiene-styrene block copolymer (SBS) 40 mol% of selective hydrogenated product [styrene-butadiene-butylene-styrene block copolymer (SBBS)] 70 parts by weight and petroleum resin [Arakawa Chemical Co., Ltd. hydrogenated petroleum resin, Alcon P-125] 29.5 Pellets (2) obtained by melting and kneading a weight part and 0.5 parts by weight of a phenolic antioxidant with a twin screw extruder into pellets (1) of amorphous propylene resin and pellets The weight ratio of (2) (1) / (2) is dry-blended resin mixture (12) used in a mixing ratio of the 50/50, a density 0.93 g / cm ³ as a heat seal resin layer (C) resin Using a resin mixture (3) in which erucic acid amide (lubricant) and natural silica (anti-blocking agent) were added and mixed in medium density polyethylene at a ratio of erucic acid amide concentration of 1000 ppm and natural silica concentration of 3000 ppm, (A ) Extruder for layer (caliber 50 mm), (B) Extruder for layer (caliber 50 mm), (C) Extruder for layer (caliber 40 mm) and T-die / chill roll co-extrusion multilayer film production apparatus To each extruder, and co-melt extrusion is performed under the conditions of a temperature of 200 to 230 ° C., a feed block and a T-die temperature of 250 ° C., and A / B / C 3 Resealable coextruded multilayer film (X3) having an average thickness of 15 μm / 15 μm / 25 μm, an overall thickness of 55 μm, and a friction coefficient of 0.5 on the surface of the heat-seal resin layer (C). Got.

  The interlayer adhesive strength of the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) of the obtained resealable coextruded multilayer film (X1) is 5 N / 15 mm, and the pressure-sensitive adhesive resin layer (B) The interlayer adhesive strength of the heat seal resin layer (C) was 25 N / 15 mm. The surface of the oxygen gas barrier resin layer (A) was subjected to corona treatment.

  Next, a biaxially stretched nylon film substrate (thickness 25 μm) was bonded to the oxygen gas barrier resin layer (A) side of the obtained resealable coextruded multilayer film (X3) by dry lamination, and resealed. An adhesive laminate film (Y3) was obtained. At this time, a two-component curable adhesive (polyester adhesive LX63F and a curing agent KP90) manufactured by Dainippon Ink & Chemicals, Inc. was used as an adhesive for dry lamination.

  When the heat-sealing resin layer (C) and the pressure-sensitive adhesive resin layer (B) are peeled off when the heat-sealing resin layer (C) is heat-sealed with a resin layer having the same composition and peeled off, the resealable laminate film (Y3) ) Is broken and the pressure-sensitive adhesive resin layer (B) and the oxygen gas barrier resin layer (A) are separated from each other so that the pressure-sensitive adhesive resin layer (B) can be resealed in the heat seal region. It was an exposed laminate film.

  Except that the obtained resealable laminate film (Y3) was used as a lid material, measurement of seal strength, evaluation of opening feeling when opened, and measurement of reseal strength were performed in the same manner as in Example 1. Was done. The results are shown in Table 2.

Claims (9)

Oxygen gas barrier resin layer (A) containing saponified ethylene-vinyl alcohol copolymer or polyamide resin, amorphous olefin resin (b1) and / or block having styrene block and diene block The pressure-sensitive adhesive resin layer (B) containing the copolymer hydrogenated product (b2) and the heat-seal resin layer (C) containing a heat-sealable olefin resin (A) A resealable coextruded multilayer film characterized by being laminated by a coextrusion method in the order of / (B) / (C). The pressure-sensitive adhesive resin layer (B) contains an amorphous olefin resin (b1) and / or a hydrogenated product (b2) of a block copolymer having a styrene block and a diene block, and a tackifier (b3). The resealable coextruded multilayer film according to claim 1, which is a resin layer. The resealable co-polymer according to claim 2, wherein the amorphous olefin resin (b1) is an amorphous olefin resin having a content of an α-olefin-derived component having 3 to 12 carbon atoms of 80 mol% or more. Extruded multilayer film. The resealable coextruded multilayer film according to claim 3, wherein the tackifier (b3) is at least one resin selected from the group consisting of rosin resins, terpene resins and petroleum resins. The pressure-sensitive adhesive resin layer (B) comprises an amorphous olefin resin (b1), a rubbery thermoplastic resin (b2), and a tackifier (b3), with a weight ratio (b1) / (b2) of 30/70 to The resealable coextruded multilayer film according to claim 3, which is a resin layer containing 80/20 and a weight ratio (b1 + b2) / (b3) of 60/40 to 90/10. The resealable coextruded multilayer film according to any one of claims 1 to 5, wherein the heat seal resin layer (C) is a resin layer containing a propylene resin or an ethylene resin. The interlayer adhesion strength between the oxygen gas barrier resin layer (A) and the pressure-sensitive adhesive resin layer (B) is 2 to 15 N / 15 mm, and the total of the pressure-sensitive adhesive resin layer (B) and the heat seal resin layer (C) The resealable coextruded multilayer film according to any one of claims 1 to 5, which has a thickness of 13 to 60 µm. A resealable laminate film, wherein a base material is laminated on the oxygen gas barrier resin layer (A) of the resealable coextruded multilayer film according to any one of claims 1 to 8. . The resealable laminate film according to claim 8, wherein the substrate is a stretched film.