JP2016117515A - Heat-sealing film and packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer film which can reduce the thickness in a packaging material and has excellent aroma retention property.SOLUTION: A multilayer film has at least a seal layer (A) and a resin layer (B). One surface layer is the seal layer (A). A film having aroma retention property can achieve thin thickness and suitable aroma retention property, in which the resin layer (B) contains a cyclic polyolefin resin, a thickness between the surface on the seal layer (A) side of the resin layer (B) and the surface of the seal layer (A) which becomes one surface layer of the multilayer film is 1-15 μm, the thickness of the seal layer (A) is 1-10 μm, and the total thickness is 50 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a heat sealing film used for packaging viscous materials, and a packaging material using the heat sealing film.

  Food sticky materials used in various foods such as confectionery and bread paste flower pastes tend to remain on the surface of the packaging material when taken out from the packaging material. Is required to be away from viscous materials.

  As a packaging material having releasability (removability) with respect to a viscous material, for example, a packing shrinkage packaging body in which a film of a nonionic surfactant is formed on the surface of a polyolefin resin sealant layer is disclosed. (See Patent Document 1). It is disclosed that the packaging body is provided with a surfactant film on the surface in contact with the viscous material and shrink-wrapped to ensure releasability for the viscous material.

JP 2001-48229 A

  However, since the above-mentioned filling shrinkage package uses a surfactant in the sealing layer in order to impart releasability, the adhesive strength of the sealing layer tends to be low, and is used for heavy business use. In some cases, the sealing strength may be insufficient. Moreover, in order to give fixed sealing strength, since the usage-amount of surfactant is restrict | limited largely, it was difficult to ensure the separability of a viscous thing fully.

  In addition, if the surfactant is simply used, the surfactant may fall off during the transfer, and if it is not contracted, it may not be able to stably keep away from it, or it may be contracted after filling the contents. Since it was necessary, there was a problem that the number of steps increased and the cost increased.

  The present invention is intended to solve the above-described problems. Even when used for packaging viscous materials, the present invention provides a good sealability with viscous materials and has a suitable sealing strength. The object is to provide a film.

  The present invention is a heat sealing film used for packaging viscous materials, wherein the surface in contact with the viscous material is a heat sealing film comprising a sealing layer containing a polybutene-1-based resin. Is a solution.

  The film for heat sealing of the present invention contains a polybutene-1 resin as a sealing layer, so that it is possible to suitably secure the releasability of the viscous content without using a surfactant or the like, which is favorable. Seal strength can be realized. For this reason, it can be suitably applied to the packaging use of viscous foods used in various foods such as confectionery and bakery material flour pastes, in particular, the packaging use of heavy goods for business use.

  In addition, since it does not require the formation of a surfactant layer or a shrinking step after filling the contents, film formation and food filling can be performed at low cost.

  The film for heat sealing of the present invention is a laminated film used for packaging viscous materials, and the surface in contact with the viscous material is a laminated film comprising a sealing layer containing a polybutene-1 resin.

[Seal layer]
The sealing layer used for the heat sealing film of the present invention is a sealing layer containing a polybutene-1 resin. As the polybutene-1 resin, a homopolymer of a butene-1 monomer or a copolymer of a butene-1 monomer and another α-olefin can be used. The α-olefin may be used alone or in combination of two or more. Examples of the α-olefin include ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and the like. Among these, a homopolymer of a butene-1 monomer, an ethylene-butene-1 copolymer having a butene-1 monomer as a main component, a propylene-butene-1 copolymer, and the like can be preferably used. As content of the butene-1 monomer in polybutene-1 type-resin, 60-100 mol% is preferable and 70-100 mol% is more preferable. The melting point of the polybutene-1 resin is preferably 70 to 140 ° C, more preferably 80 to 135 ° C, and further preferably 90 to 130 ° C. If melting | fusing point is this range, it will become easy to prevent blocking of films, and it will become easy to obtain suitable low-temperature heat-sealing property.

  Said melting | fusing point can be measured using a differential scanning calorimeter (DSC). As a differential scanning calorimeter device used for the melting point measurement, for example, “DSC6200” manufactured by Seiko Electronics Industry Co., Ltd. can be used. The melting points of the resins described below can be measured in the same manner.

The density of the polybutene-1 resin is preferably 0.89~0.93g / cm ^3, more preferably 0.90~0.92g / cm ^3. If the density is within this range, moderate rigidity can be easily obtained, blocking is small, mechanical strength such as pinhole resistance is excellent, and film film formability and extrusion suitability are improved. The melt flow rate of the polybutene-1 resin (measured at 190 ° C. and 21.18 N in accordance with JIS K7210; hereinafter referred to as “MFR”) is 0.1 to 50 g / 10 min. Preferably, 1 to 45 g / 10 min is more preferable. When the MFR is within this range, the extrusion moldability of the film is improved.

  The seal layer used in the present invention may be a seal layer made only of the polybutene-1 resin or a seal layer containing another resin. As said other resin, the heat-sealable thermoplastic resin used for a packaging material etc. can be used preferably, Polyolefin-type resin other than the said polybutene-1 type-resin, polyester-type resin, and polystyrene-type resin can be used preferably. Especially, since it is easy to obtain suitable heat-sealing property at low cost, polyolefin resin can be preferably used.

  As said polyolefin resin, the homopolymer or copolymer of a C2-C6 alpha olefin is mentioned. The copolymerization type may be a block copolymer or a random copolymer.

  As said polyolefin resin, what is known as polyethylene resin, polypropylene resin, cyclic olefin resin etc. can be used preferably, for example. These resins may be used alone or in combination. Among these, polyethylene resin is preferable because it is easy to obtain suitable heat sealability and easy peel properties.

  Examples of the polyethylene resin include very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high Polyethylene resin such as density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate ( EMA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) Copolymer, further ethylene-acrylic acid Ionomeric polymers, ethylene - ionomers of methacrylic acid copolymer. Among these, LDPE, LLDPE, LMDPE, and MDPE are preferable because a suitable heat sealability and pinhole resistance can be easily obtained, and branched LDPE obtained by a high-pressure radical polymerization method is particularly preferable.

Preferably the density of the polyethylene resin is 0.880~0.970g / cm ^3, more preferably particularly ^{0.905~0.965g / cm 3, 0.915~0.935g / cm} 3 Is more preferable, and 0.915 to 0.930 g / cm ³ is particularly preferable. If the density is within this range, it is easy to have appropriate rigidity, mechanical strength such as pinhole resistance is excellent, and it is easy to improve film film formability and extrusion suitability. Moreover, it is preferable that melting | fusing point is the range of 95-130 degreeC, 100-125 degreeC is more preferable, and 105-115 degreeC is further more preferable. If the melting point is within this range, the film shrinks little even when heated during secondary molding, and this is advantageous in maintaining the appearance of the film and suppressing warpage of the film itself. Moreover, it becomes easy to improve the sealing performance when heat-sealing with the sealing layers inside.

  Further, the melt flow rate of polyethylene resin (in accordance with JIS K7210, measured at 190 ° C. and 21.18 N; hereinafter referred to as “MFR”) is preferably 1 to 50 g / 10 minutes, preferably 3 to 45 g / 10 minutes is more preferable, and 5 to 40 g / 10 minutes is more preferable. If MFR is within this range, it is preferable because extrusion moldability is improved.

  The content of the polybutene-1-based resin in the seal layer is preferable because it is easy to realize suitable separation of the film obtained to be 3% by mass or more in the resin component included in the seal layer. Moreover, it is more preferable that it is 5-70 mass%, and it is further more preferable that it is 8-60 mass% since it is easy to acquire the more suitable personality and easy peel property.

  When the polybutene-1 resin and the polyethylene resin are used in combination, the content of the polyethylene resin in the resin component contained in the seal layer is preferably 97% by mass or less, and is 50 to 95% by mass. It is preferable that it is 70 to 92% by mass. The total amount of the polybutene-1 resin and the polyethylene resin in the resin component contained in the seal layer is preferably 80% by mass or more, more preferably 90 to 100% by mass, and substantially polybutene- More preferably, the sealing layer is made of a 1-series resin and a polyolefin-series resin. By setting it as the said content, it becomes easy to ensure moderate sealing strength suitable for easy opening property, and transparency suitably with a separability.

  In the sealing layer, in addition to the above resin components, anti-fogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, UV absorbers as necessary Components such as a colorant and a colorant can be added within a range that does not impair the object of the present invention. In particular, the surface friction coefficient is preferably 1.5 or less, more preferably 1.0 or less in order to impart processing suitability when forming a film or packaging suitability when used as a packaging material. It is preferable to add an antistatic agent as appropriate. When these additives such as a lubricant and an antistatic agent are contained, the amount is preferably 10 parts by mass or less, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin component contained in the seal layer.

[Heat seal film]
The film for heat sealing of the present invention may be a film composed of the above-mentioned single sealing layer or a laminated film with other layers. A laminated film obtained by laminating a highly rigid layer or various functional layers as another layer is preferable because it can improve strength, rigidity, heat resistance, barrier properties such as oxygen and water vapor, and pinhole resistance.

  The thickness of the heat sealing film of the present invention may be appropriately adjusted depending on the use mode, but is preferably 15 to 150 μm because it is easy to ensure suitable heat sealing properties and film forming properties, and 20 to 100 μm. Is more preferable, and it is more preferable that it is 25-60 micrometers.

  Moreover, when giving the suitable easy peel property when making the film for heat seals of this invention into a laminated film, the thickness of the seal layer (A) in the film for heat seals shall be 1.5 micrometers or more. It is preferably 3 to 50 μm, more preferably 5 to 25 μm.

  When the heat sealing film of the present invention has a laminated structure, the structure is not particularly limited as long as the sealing layer is a surface layer, and the sealing layer (hereinafter may be referred to as “sealing layer (A)”). Two-layer configuration with resin layer (B) ((A) / (B)), three-layer configuration with seal layer (A), resin layer (B) and resin layer (C) ((A) / (B) / (C)) and a four-layer structure ((A) / (B) / (C) / (D)) in which a resin layer (D) is further laminated can be used. Each of the resin layers (B) to (D) may be appropriately selected according to the laminated form, application, and the like.

  Examples of the resin used for the resin layers (B) to (D) include polyolefin resins, polyester resins, polystyrene resins, polyamide resins, ethylene-vinyl alcohol copolymers, and the like exemplified in the seal layer (A). Can be preferably used. Among these, polyolefin resins can be preferably used because they are inexpensive and easy to stack and handle with the seal layer (A).

  As the polyolefin resin used for the resin layers (B) to (D), for example, those known as polyethylene resins, polypropylene resins, cyclic olefin resins and the like can be preferably used. These resins may be used alone or in combination.

  Examples of the polyethylene resin include very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high Polyethylene resin such as density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate ( EMA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) Copolymer, further ethylene-acrylic acid Ionomeric polymers, ethylene - ionomers of methacrylic acid copolymer. Among these, linear low-density polyethylene is preferable, and an ethylene monomer as a main component and butene-1, hexene-1, octene-1, and 4 as comonomers by a low-pressure radical polymerization method using a single site catalyst. -Copolymerized α-olefin such as methylpentene. As comonomer content in a linear low density polyethylene, 0.5-10 mol% is preferable and 1-7 mol% is more preferable. In addition, when hexene-1 and octene-1 are used as a comonomer, since transparency, impact resistance, etc. improve, it is especially preferable.

Preferably the density of the polyethylene resin is 0.880~0.970g / cm ^3, more preferably particularly ^{0.905~0.965g / cm 3, 0.915~0.935g / cm} 3 Is more preferable, and 0.915 to 0.930 g / cm ³ is particularly preferable. If the density is within this range, it is easy to have appropriate rigidity, mechanical strength such as pinhole resistance is excellent, and it is easy to improve film film formability and extrusion suitability. Moreover, it is preferable that melting | fusing point is the range of 95-130 degreeC, 100-125 degreeC is more preferable, and 105-115 degreeC is further more preferable. If the melting point is within this range, the film shrinks less even when heated during secondary molding, and this is advantageous for maintaining the appearance of the film.

  Further, the melt flow rate of polyethylene resin (in accordance with JIS K7210, measured at 190 ° C. and 21.18 N; hereinafter referred to as “MFR”) is preferably 1 to 50 g / 10 minutes, preferably 3 to 45 g / 10 minutes is more preferable, and 5 to 40 g / 10 minutes is more preferable. If MFR is within this range, it is preferable because extrusion moldability is improved.

  Examples of the polypropylene resin include a propylene homopolymer, a copolymer of propylene and an α-olefin such as ethylene and butene-1, and the copolymer includes a random copolymer and a block copolymer. Any of these can be used. Among them, preferred are propylene-ethylene random copolymer, propylene-ethylene-butene-1 random copolymer and the like. These propylene-based resins may be used alone or in combination.

  As the resin layers (B) to (D), by using a heat-resistant polypropylene resin, polyamide resin, and polyester resin, the film is not melted by sticking to the heat seal or sticks to the seal bar. This is preferable.

  Examples of the polyamide resin having high heat resistance include aliphatic nylon such as 6 nylon and 6-6 nylon, and aromatic nylon represented by MXD nylon. In addition, as the polyester having high heat resistance, the polybutylene terephthalate resin having high crystallinity and the resin layers (B) to (D) having a high copolymer glass transition point of a bulky diol component and polyethylene terephthalate are used. It is preferable to use a high polypropylene resin, polyamide resin, and polyester resin because the film is not melted by the heat seal and does not stick to the seal bar.

  The sealing resin layer (A), the resin layers (B), (C) and (D) of the coextruded multilayer film of the present invention may include an antifogging agent, an antistatic agent, a heat stabilizer, 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, in order to provide processing suitability during film forming and packaging suitability when used in a filling machine, the friction coefficient of the surface of the sealing resin layer (A) and the back layer thereof is 1.5 or less, especially 1.2 or less. Therefore, it is preferable to add a lubricant or an antiblocking agent to these resin layers as appropriate.

  The method for producing the heat-sealing film of the present invention is not particularly limited, but the resin constituting the heat-sealing film is heated and melted with an extruder and formed into a film shape by inflation, T-die / chill roll method, etc. can do.

  When the heat sealing film is a multilayer heat sealing film, the resin constituting each layer is heated and melted in a separate extruder, and in a molten state by a method such as a coextrusion multilayer die method or a feed block method. After lamination, a heat sealing film having a multilayer structure can be produced by a coextrusion method in which a film is formed by inflation, a T-die / chill roll method or the like. Further, even when the heat sealing film is only the sealing layer, the resin forming the sealing layer may be coextruded in the same manner using a plurality of extruders. This coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a multilayer film excellent in hygiene and cost performance can be obtained.

  Furthermore, the heat sealing film of the present invention may be stretched in at least one axial direction. As the stretching method, a known method such as longitudinal or lateral uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, or tubular method biaxial stretching can be employed. Further, the stretching process may be inline or offline. The stretching method for uniaxial stretching may be a proximity roll stretching method or a rolling method. The stretching ratio of uniaxial stretching is preferably 1.1 to 80 times, more preferably 3 to 30 times in the longitudinal or transverse direction. On the other hand, the draw ratio of biaxial stretching is preferably 1.2 to 70 times in terms of area ratio, more preferably 4 to 6 times in length, 5 to 9 times in width, and 20 to 54 times in terms of area ratio.

  In addition, the longitudinal or lateral stretching step is not necessarily limited to one-stage stretching, and may be multi-stage stretching. In particular, in longitudinal uniaxial stretching such as longitudinal uniaxial roll stretching and longitudinal uniaxial rolling stretching in sequential biaxial stretching, it is preferable to perform multistage stretching in terms of uniformity of thickness and physical properties. Further, in the proximity roll stretching, either a flat method or a cross method may be used, but multistage proximity cross stretching that can reduce width shrinkage is more preferable. By stretching, the rigidity of the film is improved, so that it is easy to handle.

  Since the heat-sealing film of the present invention is easy to obtain suitable packaging suitability and bag-breaking resistance, the sealing layers are sealed when heat-sealed for 0.1 seconds at a temperature of 170 ° C. and a sealing pressure of 0.2 MPa. The strength is preferably 2 N / 15 mm or more.

[Packaging materials]
The heat sealing film of the present invention can be used alone or as a packaging material by laminating a substrate such as another film. The packaging material has the sealing layer (A) in the heat-sealing film as one surface layer, is processed into an appropriate mode, and the sealing layer (A) of one or more packaging materials is heat-sealed. Thus, various packaging bags can be formed.

  As a structural example of the packaging material using the heat sealing film of the present invention, a structure in which a heat sealing film and a substrate are laminated can be exemplified.

  Examples of the material constituting the base material include polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, resin films such as polypropylene resin, polyethylene resin, and cellophane, paper, paperboard, and fabrics. And a metal foil such as an aluminum foil, preferably a film made of polyamide resin, polyester resin or polypropylene resin, or aluminum foil. When the substrate is a film made of polyamide resin, polyester resin or polypropylene resin, it is preferably a stretched film. Further, the substrate may be a single layer or a multilayer. Examples of the multi-layer base material include a polyamide resin layer, an ethylene-vinyl alcohol copolymer resin layer, a three-layer base material laminated in the order of the polyamide resin layer, and a base material obtained by laminating a polyester resin layer and an aluminum foil. It is done. Among these, a base material using a polyamide resin such as nylon 6 or nylon 66 is preferable because suitable heat resistance and pinhole resistance are easily obtained. In addition, a base material using a polyester resin is preferable because suitable heat resistance is easily obtained.

  Moreover, the base material by which various functional layers were laminated | stacked on said resin film, metal foil, etc. may be sufficient, for example, you may have a barrier layer which blocks permeation | transmission of oxygen gas, water vapor | steam, etc.

  Examples of the barrier layer include a vapor deposition layer of an inorganic oxide such as silicon oxide or aluminum oxide, a polyvinylidene chloride resin layer, a vinyl alcohol resin layer, an ethylene-vinyl alcohol copolymer layer, a polyacrylonitrile resin layer, and a polyamide system. Examples thereof include a resin layer. In particular, a vapor deposition layer of an inorganic oxide such as silicon oxide or aluminum oxide is preferably used as the barrier layer. The laminate of the present invention having an inorganic oxide vapor-deposited layer has an advantage of excellent storage stability of contents.

  The barrier layer is a method of depositing an inorganic oxide on one side of the resin film or metal foil by physical vapor deposition or chemical vapor deposition, or a coating method such as roll coating, gravure roll coating, or kiss coating. And a method of forming a barrier layer by applying a solution in which a resin is dissolved by a printing method such as gravure printing, offset printing, or transfer printing.

  The thickness of the base material may be appropriately adjusted according to the mode to be used, but it is preferably 5 to 30 μm and preferably 10 to 20 μm because it is easy to obtain suitable heat sealability at low cost. More preferred.

  Examples of the method for laminating the heat sealing film and the substrate through an adhesive include known methods such as a dry laminating method, a wet laminating method, a sand laminating method, and a hot melt laminating method.

  Examples of the adhesive used for bonding the heat sealing film and the substrate include adhesive resins such as a two-component curable polyurethane adhesive, an epoxy adhesive, and an acid-modified olefin resin adhesive.

  The heat-sealing film of the present invention contains a polybutene-1 resin and a low-density polyethylene resin in the sealing layer in the above-mentioned composition, so that it can be used to remove food sticky foods such as flour paste and flour sheets (release function). In addition, a packaging material made of a laminate film using this film as a sealant can be suitably used as a packaging material for pillow bag type flower pastes and flower sheets.

  The packaging material of the present invention can take advantage of the ability to heat-seal between sealing surfaces, and can package contents by forming into a bag shape.

Example 1
Polybutene-1 resin (1) (ethylene-butene-1 copolymer, MFR: 4 g / 10 min, melting point: 104 ° C., butene-1 monomer content: 83 as the resin for the sealing layer (A) A resin containing 13% by mass of mol%) and 87% by mass of low-density polyethylene (1) (MFR: 35 g / 10 min, melting point: 105 ° C., density: 0.919 g / cm ³ ) was used. Medium density polyethylene (1) (MFR: 8 g / 10 min, melting point: 125 ° C., density: 0.933 g / cm ³ ) was used as the resin for the resin layer (B) and the resin layer (C). These resins were respectively supplied to a seal layer (A) extruder (50 mm diameter), a resin layer (B) extruder (50 mm diameter), and a resin layer (C) extruder (50 mm diameter) at 230 ° C. The melted resin is supplied to a co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 250 ° C.) of a T-die / chill roll method having a feed block, and the layer structure of the film is (A) / (B) / (C) in a three-layer configuration, each layer has a thickness of 10 μm / 30 μm / 10 μm (total 50 μm), melt-extruded, cooled with a cooling roll, and then the resin layer (C) The surface was subjected to corona discharge treatment so that the wetting tension was 40 mN / m, to obtain a heat-sealing film (1) comprising a coextruded multilayer film.

(Example 2)
A heat seal film (2) was obtained in the same manner as in Example 1 except that only the polybutene-1 resin (1) was used as the resin for the seal layer (A).

(Example 3)
As resin for sealing layer (A), polybutene-1 resin (2) (MFR: 4 g / 10 min, melting point: 90 ° C., butene-1 monomer content: 85 mol%) 7% by mass, low density A heat sealing film (3) was obtained in the same manner as in Example 1 except that a resin containing 93% by mass of polyethylene (1) was used.

Example 4
For heat sealing, as in Example 1, except that the resin containing 9% by mass of polybutene-1 resin (2) and 91% by mass of low-density polyethylene (1) was used as the resin for the sealing layer (A). A film (4) was obtained.

(Example 5)
For heat sealing, as in Example 1, except that the resin containing 13% by mass of polybutene-1 resin (2) and 87% by mass of low density polyethylene (1) was used as the resin for the sealing layer (A). A film (5) was obtained.

(Example 6)
For heat sealing, as in Example 1, except that the resin for sealing layer (A) was 30% by mass of polybutene-1 resin (2) and 70% by mass of low-density polyethylene (1). A film (6) was obtained.

(Example 7)
For heat sealing, as in Example 1, except that the resin containing 40% by mass of polybutene-1 resin (2) and 60% by mass of low density polyethylene (1) was used as the resin for the sealing layer (A). A film (7) was obtained.

(Example 8)
For heat sealing, as in Example 1, except that the resin containing 50% by mass of polybutene-1 resin (2) and 50% by mass of low-density polyethylene (1) was used as the resin for the sealing layer (A). A film (8) was obtained.

Example 9
As for the sealing layer (A), the resin for heat sealing was used in the same manner as in Example 1 except that a resin containing 60% by mass of polybutene-1 resin (2) and 40% by mass of low-density polyethylene (1) was used. A film (9) was obtained.

(Example 10)
For heat sealing, as in Example 1, except that the resin containing 70% by mass of polybutene-1 resin (2) and 30% by mass of low-density polyethylene (1) was used as the resin for the sealing layer (A). A film (10) was obtained.

(Example 11)
For heat sealing, as in Example 1, except that the resin containing 80% by mass of polybutene-1 resin (2) and 20% by mass of low-density polyethylene (1) was used as the resin for the sealing layer (A). A film (11) was obtained.

(Example 12)
A heat seal film (12) was obtained in the same manner as in Example 1 except that only the polybutene-1 resin (2) was used as the resin for the seal layer (A).

(Comparative Example 1)
A laminated film (H1) was obtained in the same manner as in Example 1 except that only the low density polyethylene (1) was used as the resin for the seal layer (A).

(Comparative Example 2)
Implemented except using only ethylene-vinyl acetate copolymer (EVA) (MFR: 2.4 g / 10 min, melting point: 85 ° C., density: 0.94 g / cm ³ ) as the resin for the sealing layer (A). In the same manner as in Example 1, a laminated film (H2) was obtained.

(Comparative Example 3)
As a resin for the sealing layer (A), only propylene-ethylene random copolymer (hereinafter referred to as polypropylene (1)) (MFR: 9 g / 10 min, melting point: 140 ° C., density: 0.89 g / cm ³ ) A laminated film (H3) was obtained in the same manner as in Example 1 except that it was used.

(Comparative Example 4)
As the resin for the sealing layer (A), high density polyethylene (HDPE) (MFR: 8 g / 10 min, melting point: 134 ° C., density: 0.96 g / cm ³ ) 50% by mass, polypropylene (1) 50% by mass is contained. A laminated film (H4) was obtained in the same manner as in Example 1 except that the resin used was used.

(Comparative Example 5)
As resin for sealing layer (A), high density polyethylene (MFR: 8 g / 10 min, melting point: 134 ° C., density: 0.96 g / cm ³ ) 50% by mass, polypropylene (1) 30% by mass, and nonionic interface As a resin for the resin layer (B), 20% by mass of an active agent master batch (Riken Vitamin Co., Ltd., Riquet Master PAR-380, surfactant concentration 10% by mass, hereinafter referred to as master batch (1)) is mixed. A laminated film (H5) was obtained in the same manner as in Example 1 except that 95% by mass of medium density polyethylene (1) and 5% by mass of master batch (1) were mixed and used.

  The following evaluation was performed about the film obtained by the said Example and comparative example. The results obtained are shown in the table. In addition, the numerical value of resin of each layer in a table | surface is content (mass%) of each resin in resin which forms each layer.

[Separation]
A biaxially stretched polyethylene terephthalate film having a thickness of 12 μm is dry-laminated using a polyurethane-based adhesive (Dick Dry LX500 / KR90S) on the corona-treated surface side of the resin layer (C) side of the obtained film, and 38 ° C. Was aged for 2 days to obtain a test film. Bag making so that the inner dimension is 30 mm x 100 mm with the sealing layer (A) on the inside, filling 12-15 g of hot cake mix to which a predetermined amount of water is added, and the film and contents are brought into close contact with each other. The bag was heat sealed. After storing this packaging body at 3 ° C. for 24 hours, the weight of the contents attached to the film surface when the film was peeled off was measured, and the weight of the contents attached per unit area of the film was calculated. The ability to leave was evaluated based on the criteria.
A: Adhesion weight of contents is less than 200 g / m ² O: Adhesion weight of contents is 200 to 350 g / m ²
(Triangle | delta): The adhesion weight of the content is 350-400 g / m < ² >.
X: The attached weight of the contents is 400 g / m ² or more.

[Seal strength]
The seal layers (A) of the test film were sealed under the conditions of a seal temperature of 170 ° C., a seal time of 0.1 S, and a seal pressure of 0.2 MPa. The sealed film was naturally cooled at 23 ° C., and then a sample was cut into a strip shape having a width of 15 mm. The cut sample was peeled 90 degrees at a rate of 300 mm / min using a tensile tester (manufactured by A & D Co., Ltd.) in a thermostatic chamber at 23 ° C. and 50% Rh, and the heat seal strength was measured. . From the value of the obtained heat seal strength, the heat seal strength was evaluated according to the following criteria.
○: Heat seal strength is 2N / 15mm width or more ×: Heat seal strength is less than 2N / 15mm width

  As is clear from the above table, the heat-sealing films of the present inventions of Examples 1 to 6 had good sealing properties and the ability to leave a viscous material. Further, the heat sealing films of Examples 1 and 3 to 10 can be suitably peeled off without causing stringing, and the heat sealing films of Examples 1 and 4 to 9 are particularly preferably easily peelable. It had easy peel properties. On the other hand, the laminated films of Comparative Examples 1 to 4 were inferior to the separability of viscous materials. Moreover, the laminated film of Comparative Examples 1-3 was inferior also in easy peel property.

Claims (6)

  A film for heat sealing, characterized in that it is a film used for packaging viscous materials, and a surface in contact with the viscous material is composed of a sealing layer containing a polybutene-1 resin.   The heat sealing film according to claim 1, wherein the sealing layer contains a polyethylene resin.   The film for heat sealing according to claim 1 or 2, wherein the content of the polybutene-1 resin in the resin component contained in the sealing layer is 3% by mass or more.   The film for heat sealing according to claim 2 or 3, wherein the content of the polyethylene resin in the resin component contained in the sealing layer is 5 to 97% by mass.   The film for heat sealing according to any one of claims 1 to 4, wherein a sealing strength when the sealing layers are heat sealed at 170 ° C and 0.2 MPa for 0.1 second is 2 N / 15 mm or more.   A packaging material comprising the heat sealing film according to claim 1.