Laminated sealant film

Abstract

The present invention provides a laminated sealant film that has excellent low temperature bag-making properties and heat sealing strength and that comprises a propylene resin and a polyethylene resin, said laminated sealant film satisfying all of conditions 1) to 8) below. 1) The laminated sealant film includes at least a laminate layer and a sealing layer. 2) The laminate layer comprises a resin composition having, as the main component, a polypropylene resin. 3) The sealing layer comprises a resin composition having, as the main component, a mixture of a polypropylene resin and a polyethylene resin. 4) With respect to 100 mass% of the mixture of the polypropylene resin and the polyethylene resin constituting the sealing layer, the polypropylene resin is contained in an amount of 1-90 mass%, and the polyethylene resin is contained in an amount of 10-99 mass%. 5) The polyethylene resin constituting the sealing layer contains not less than 90 mass% of a straight-chain linear polyethylene resin. 6) There is a difference of not less than 15°C between the respective melting points of the straight-chain linear polyethylene resin and the polypropylene resin of the sealing layer. 7) The ratio of the melt flow rate of the polypropylene resin with respect to the melt flow rate of the straight-chain linear polyethylene resin of the sealing layer is 0.5-2.0. 8) The melt flow rates of the straight-chain linear polyethylene resin and the polypropylene resin of the sealing layer are not more than 9 g / 10 minutes.

Description

Laminated Sealant Film

[0001] The present invention relates to a laminated sealant film having excellent bag-forming properties, low-temperature bag-forming properties, and excellent seal strength.

[0002] Packaging materials have been developed to suit the contents of many products, such as foods, beverages, pharmaceuticals, and chemicals. Packaging materials are used in various forms, such as pillow packaging, gusset packaging, and three-sided seal packaging, and the sealant films used in packaging materials also have the required functions depending on the application.

[0003] The lower the temperature at which sealant film can be heat-sealed, the better. It is particularly suited to automated bag-making processes for pillowcase bags, gusset bags, and three-sided seal bags while packaging the contents, improving workability by reducing electricity costs and the risk of burns. It also leads to increased packaging and bag-making speed and reduced packaging material waste. It also produces cleaner finished packaging bags. However, sealant film must be able to perform packaging and bag-making processes smoothly, and the resulting packaging bags must also have various functions, such as airtightness and good seal strength.

[0004] For example, when heavy contents are packaged in vertical pillowcases automatically, it is required that the seal strength be sufficient even immediately after heat sealing when the resin of the sealant film is in a molten state, and that the seal portion will not peel off even when subjected to the impact of pressure generated when the heavy contents are filled into the bag.

[0005] Furthermore, when the contents are packaged in horizontal pillow packaging automatically, the sealant film must have sufficient seal strength even when the resin is in a molten state, and the seal must not peel off due to high-pressure gas (nitrogen flush) when filling the bag. None of the conventional sealant films have satisfied all of the following requirements: bag formability, low-temperature bag formability, and heat seal strength (see, for example, Patent Documents 1 to 5).

[0006] Japanese Patent No. 4731699 Japanese Patent Application Laid-Open No. 2000-272064 Japanese Patent Application Laid-Open No. 2000-272065 Japanese Patent Application Laid-Open No. 2020-241716 Japanese Patent Application Laid-Open No. 2020-192695 Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a sealant film containing a propylene-based resin and a polyethylene-based resin, which has excellent low-temperature bag-forming properties and heat-sealing strength.

[0008] As a result of extensive research conducted to achieve the above object, the present invention has succeeded in obtaining a laminate sealant film having excellent low-temperature bag-forming properties and seal strength by controlling the raw material composition of each layer of the laminate sealant film. That is, the laminate sealant film of the present invention has the following composition.

[0009] [1] A laminate sealant film that satisfies all of the following requirements 1) to 8). 1) The laminate sealant film includes at least a laminate layer and a seal layer. 2) The laminate layer is made of a resin composition primarily composed of a polypropylene-based resin. 3) The seal layer is made of a resin composition primarily composed of a mixture of a polypropylene-based resin and a polyethylene-based resin. 4) The seal layer contains 1% by weight or more and 90% by weight or less of a polypropylene-based resin and 10% by weight or more and 99% by weight or less of a polyethylene-based resin, relative to 100% by weight of the mixture of a polypropylene-based resin and a polyethylene-based resin that constitutes the seal layer. 5) The polyethylene-based resin that constitutes the seal layer contains 90% by weight or more of a linear polyethylene resin. 6) The difference in melting point between the polypropylene-based resin and the linear linear polyethylene resin in the seal layer is 15°C or more. 7) The ratio of the melt flow rate of the polypropylene-based resin to the melt flow rate of the linear linear polyethylene resin in the seal layer is 0.5 or more and 2.0 or less. 8) The polypropylene-based resin and the linear polyethylene resin in the seal layer have melt flow rates of 9 g / 10 min or less. [2] The laminate sealant film according to [1] above, wherein the polypropylene-based resin in the seal layer is a propylene random copolymer. [3] The laminate sealant film according to [1] or [2] above, wherein the tensile modulus of elasticity in the longitudinal direction of the film is less than 600 MPa. [4] The laminate sealant film according to any one of [1] to [3] above, wherein the main peak of the melting point of the film is 120°C or higher. [5] The laminate sealant film according to any one of [1] to [4] above, wherein the static friction coefficient between the sealing surfaces is 0.5 or less. [6] The laminate sealant film according to any one of [1] to [5] above, wherein the kinetic friction coefficient between the sealing surfaces is 0.5 or less. [7] The laminate sealant film according to any one of [1] to [6] above, wherein the seal layer contains organic particles as an antiblocking agent. [8] The laminate sealant film according to any one of [1] to [7], wherein the sealing layer contains two or more types of fatty acid amides as organic lubricants.

[0010] The laminated sealant film of the present invention has excellent low-temperature bag-forming properties and is therefore suitable as a packaging material for many products, such as foods, beverages, pharmaceuticals, and chemicals. It is particularly suitable for automatic bag-forming processing into pillow packaging bags, gusset packaging bags, three-side seal packaging bags, etc. while packaging the contents.

[0011] The present invention will be described below. The laminated sealant film of the present invention includes at least a laminate layer and a sealing layer. The laminate layer and the sealing layer will be described in detail below.

[0012] (Sealing layer) The sealing layer in the present invention is made of a resin composition mainly composed of a mixture of polypropylene resin and polyethylene resin. Here, "main component" means that the mixture of polypropylene resin and polyethylene resin accounts for 90% by mass or more of the resin composition, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0013] (Polypropylene Resin) The polypropylene resin in the seal layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, random copolymers and block copolymers of propylene with α-olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Note that "main component" means that the proportion of propylene in the polypropylene resin is 90% by mass or more, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0014] The polypropylene resin constituting the sealing layer preferably has a melt flow rate of 0.1 g / 10 min or more and 9 g / 10 min or less, more preferably 0.5 g / 10 min or more and 8 g / 10 min or less, and even more preferably 1 g / 10 min or more and 7 g / 10 min or less. The polypropylene resin constituting the sealing layer preferably has a melting point of 120°C or more, more preferably 125°C or more and 150°C or less, and even more preferably 130°C or more and 140°C or less.

[0015] The polypropylene resin content is preferably 1% by weight or more and 90% by weight or less, and more preferably 5% by weight or more and 90% by weight or less, relative to 100% by weight of the mixture of polypropylene resin and polyethylene resin constituting the seal layer. When the polypropylene resin content is 1% by weight or more, the slipperiness is excellent and the ultimate heat seal strength is less likely to vary.

[0016] (Polyethylene Resin) The polyethylene resin in the seal layer is primarily composed of linear low-density polyethylene. In addition to linear low-density polyethylene, at least one ethylene homopolymer selected from the group consisting of high-pressure low-density polyethylene, medium-density polyethylene, and high-density polyethylene can be used. Furthermore, random or block copolymers containing ethylene as the main component and copolymerized with other monomers such as α-olefins (e.g., propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1), vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof, can also be used. These may be crystalline, low-crystalline, or amorphous.

[0017] The polyethylene resin constituting the sealing layer has a melt flow rate of 0.1 to 9 g / 10 min, preferably 0.5 to 8 g / 10 min, more preferably 1 to 7 g / 10 min, and a melting point of 100 to 140°C, preferably 105 to 135°C, more preferably 110 to 130°C.

[0018] The polyethylene resin constituting the sealing layer preferably contains 90% by weight or more of straight-chain linear polyethylene resin, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0019] The seal layer preferably contains 1% by weight or more and 90% by weight or less of polypropylene resin and 10% by weight or more and 99% by weight or less of polyethylene resin, and more preferably 20 to 90% by weight, based on 100% by weight of the mixture of polypropylene resin and polyethylene resin constituting the seal layer. If the polypropylene resin content is less than 1% by weight, delamination between the seal layer and the intermediate layer is likely to occur, resulting in variations in the sealing strength and seal strength. The difference in melting point between the polypropylene resin and the polyethylene resin constituting the seal layer is preferably 15°C or more, more preferably 16°C or more, even more preferably 17°C or more, even more preferably 18°C ​​or more, and particularly preferably 19°C or more. If the difference in melting point between the polypropylene resin and the polyethylene resin is 15°C or more, low-temperature bag-forming properties are improved, the polypropylene resin and the polyethylene resin are well mixed, and variations in the sealing strength and seal strength are reduced. The arithmetic mean melting point of the polypropylene resin and polyethylene resin constituting the seal layer is preferably 100° C. or higher, more preferably 112° C. or higher, even more preferably 115° C. or higher, even more preferably 116° C. or higher, and particularly preferably 121° C. or higher. When the arithmetic mean melting point of the polypropylene resin and polyethylene resin is 100° C. or higher, the boiling suitability as a packaging material is improved, when it is 105° C. or higher, the semi-retort suitability is improved, when it is 116° C. or higher, the retort suitability is improved, and when it is 121° C. or higher, the high-retort suitability is improved.

[0020] (Anti-blocking agent) In the resin composition of the sealing layer, the anti-blocking agent can be inorganic particles such as synthetic silica, diatomaceous earth, talc or mica, or organic particles such as silicone particles, acrylic particles, nylon particles or polyethylene particles.The average particle size of the particles used in the present invention is preferably 2 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.The average particle size is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

[0021] The content of particles in the resin composition in the sealing layer is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, and even more preferably 0.4 wt% or more, relative to the sealing layer of the film. Also, it is preferably 2 wt% or less, more preferably 1.5 wt% or less, and even more preferably 1.0 wt% or less. If the amount of particles added is less than 0.1 wt%, it becomes difficult to achieve a surface roughness Ra of 0.1 μm or more on at least one surface layer, making it difficult to obtain anti-blocking properties and slip properties. Furthermore, if the amount of particles added is more than 2 wt%, the number of surface protrusions increases, resulting in poor appearance and poor abrasion resistance.

[0022] (Organic Lubricant) The resin composition in the seal layer preferably contains 0.01 to 2.0 wt % of fatty acid amide as an organic lubricant, more preferably 0.05 to 1.5 wt %, and particularly preferably 0.1 to 1.0 wt %. If the fatty acid amide content is less than 0.01%, blocking between films will be strong, and the film will not be easy to handle. If it is 2.0% or more, the seal strength will decrease. Examples of fatty acid amides include erucic acid amide, ethylene bisoleic acid amide, and behenic acid amide, and these may be used in combination.

[0023] The closer the melt flow rates of the resin composition or raw resins constituting the seal layer, the better the appearance. The ratio of the melt flow rates of the raw resins mixed in the seal layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. When the melt flow rate ratio is within this range, poor appearance such as layer misalignment, blemishes, and unevenness is less likely to occur.

[0024] (Laminate Layer) The laminate layer in the present invention is made of a resin composition mainly composed of a polypropylene resin. Here, "main component" means that the proportion of the polypropylene resin in the resin composition is 90% by mass or more, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0025] (Polypropylene Resin) The polypropylene resin in the laminate layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, random copolymers and block copolymers of propylene with α-olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Among these, random copolymers and / or block copolymers of propylene with α-olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1 are preferred. Note that "main component" means that propylene accounts for 90% by mass or more of the polypropylene resin, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0026] The polypropylene resin constituting the laminate layer preferably has a melt flow rate (JIS K7112) of 0.1 g / 10 min or more and 9 g / 10 min or less, more preferably 0.5 g / 10 min or more and 8 g / 10 min or less, and even more preferably 1 g / 10 min or more and 7 g / 10 min or less. The polypropylene resin constituting the laminate layer preferably has a melting point (JIS K7121) of 120°C or more and 160°C or less, more preferably 125°C or more and 155°C or less, and even more preferably 130°C or more and 150°C or less. The polypropylene resin constituting the laminate layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, random copolymers and block copolymers of propylene with α-olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Among these, a random copolymer of propylene and ethylene and / or butene-1 is preferred.

[0027] In addition to polypropylene-based resins, the resin composition of the laminate layer can also include at least one ethylene homopolymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene. Furthermore, random or block copolymers containing ethylene as the main component and copolymerized with other monomers, such as α-olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof, can also be used. These may be crystalline, low-crystalline, or amorphous.

[0028] The polyethylene resin constituting the laminate layer preferably has a melt flow rate (JIS K7112) of 0.1 g / 10 min or more and 9 g / 10 min or less, more preferably 0.5 g / 10 min or more and 8 g / 10 min or less, and even more preferably 1 g / 10 min or more and 7 g / 10 min or less. The polyethylene resin constituting the laminate layer preferably has a melting point (JIS K7121) of 100°C or more and 140°C or less, more preferably 105°C or more and 135°C or less, and even more preferably 110°C or more and 130°C or less. The melting point of the polyethylene resin may show two or more melting endothermic peaks, and the peak with the largest melting endothermic amount was defined as the main peak.

[0029] (Anti-blocking agent) In the resin composition of the laminate layer, the anti-blocking agent can be inorganic particles such as synthetic silica, diatomaceous earth, talc, mica, etc., or organic particles such as silicone particles, acrylic particles, nylon particles, polyethylene particles, etc. The average particle size of the particles used in the present invention is preferably 2 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The average particle size is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

[0030] The particle content in the resin composition in the laminate layer is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, and even more preferably 0.4 wt% or more, relative to the seal layer of the film. Also, it is preferably 2 wt% or less, more preferably 1.5 wt% or less, and even more preferably 1.0 wt% or less. If the particle content is less than 0.1 wt%, it becomes difficult to achieve a surface roughness Ra of 0.1 μm or more on at least one surface layer, making it difficult to obtain anti-blocking properties and slip properties. Furthermore, if the particle content is more than 2 wt%, the number of surface protrusions increases, resulting in poor appearance and poor abrasion resistance.

[0031] (Organic Lubricant) The resin composition in the laminate layer preferably contains 0.01 to 2.0 wt % of fatty acid amide as an organic lubricant, more preferably 0.05 to 1.5 wt %, and particularly preferably 0.1 to 1.0 wt %. If the fatty acid amide content is less than 0.01%, blocking between films will be strong, resulting in unsatisfactory film handling. If it is 2.0% or more, the seal strength will decrease. Examples of fatty acid amides include erucic acid amide, ethylene bisoleic acid amide, and behenic acid amide, and these may be used in combination.

[0032] The closer the melt flow rates of the resin compositions or raw resins constituting the laminate layer, the better the appearance. The ratio of the melt flow rates of the raw resins mixed in the seal layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. When the melt flow rate ratio is within this range, poor appearance such as layer misalignment, blemishes, and unevenness is less likely to occur.

[0033] (Intermediate layer) The laminated sealant film of the present invention may include an intermediate layer between the laminate layer and the seal layer. The intermediate layer in the present invention is made of a resin composition mainly composed of a polypropylene resin. The term "main component" means that the proportion of the polypropylene resin in the resin composition is 90% by mass or more, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0034] (Polypropylene Resin) The polypropylene resin in the intermediate layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, random copolymers and block copolymers of propylene and an α-olefin such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Among these, random copolymers of propylene and an α-olefin such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1 are preferred. Note that "main component" means that propylene accounts for 90% by mass or more of the polypropylene resin, more preferably 95% by weight or more, even more preferably 97% by weight or more, and even more preferably 99% by weight or more.

[0035] The polypropylene resin constituting the intermediate layer preferably has a melt flow rate of 0.1 g / 10 min or more and 9 g / 10 min or less, more preferably 0.5 g / 10 min or more and 8 g / 10 min or less, and even more preferably 1 g / 10 min or more and 7 g / 10 min or less. The polypropylene resin constituting the intermediate layer preferably has a melting point of 120°C or more and 160°C or less, more preferably 125°C or more and 150°C or less, and even more preferably 130°C or more and 140°C or more. The polypropylene resin constituting the intermediate layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, random copolymers and block copolymers of propylene and α-olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Among these, random copolymers of propylene and ethylene and / or butene-1 are preferred.

[0036] In addition to polypropylene-based resins, the resin composition for the intermediate layer can be, for example, at least one ethylene homopolymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene. Furthermore, random or block copolymers containing ethylene as the main component and copolymerized with other monomers such as α-olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof, can also be used. These may be crystalline, low-crystalline, or amorphous.

[0037] The polyethylene resin constituting the intermediate layer preferably has a melt flow rate of 0.1 g / 10 min or more and 9 g / 10 min or less, more preferably 0.5 g / 10 min or more and 8 g / 10 min or less, and even more preferably 1 g / 10 min or more and 7 g / 10 min or less. The polyethylene resin constituting the intermediate layer preferably has a melting point of 100°C or more and 140°C or less, more preferably 105°C or more and 135°C or less, and even more preferably 110°C or more and 130°C or less.

[0038] (Anti-blocking agent) The resin composition in the intermediate layer may contain an anti-blocking agent, and examples thereof include inorganic particles such as synthetic silica, diatomaceous earth, talc, and mica, and organic particles such as silicone particles, acrylic particles, nylon particles, and polyethylene particles. The average particle size of the particles used in the present invention is preferably 2 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The average particle size is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

[0039] The content of the particles in the resin composition in the intermediate layer is preferably 0.1 wt % or more, more preferably 0.3 wt % or more, and even more preferably 0.4 wt % or more, based on the seal layer of the film, and is preferably 2 wt % or less, more preferably 1.5 wt % or less, and even more preferably 1.0 wt % or less.

[0040] (Organic Lubricant) The resin composition in the intermediate layer preferably contains 0.01 to 2.0 wt % of fatty acid amide as an organic lubricant, more preferably 0.05 to 1.5 wt %, and particularly preferably 0.1 to 1.0 wt %. If the fatty acid amide content is less than 0.01%, blocking between films will be strong, and the film will not be easy to handle. If it is 2.0% or more, the seal strength will decrease. Examples of fatty acid amides include erucic acid amide, ethylene bisoleic acid amide, and behenic acid amide, and these may be used in combination.

[0041] The closer the melt flow rates of the resin composition or raw resins constituting the intermediate layer, the better the appearance. The ratio of the melt flow rates of the raw resins mixed in the seal layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. When the melt flow rate ratio is within this range, poor appearance such as layer misalignment, blemishes, and unevenness is less likely to occur.

[0042] (Layer structure) Examples of the layer structure of the laminated sealant film of the present invention include laminate layer / sealing layer, laminate layer / intermediate layer / sealing layer, and laminate layer / intermediate layer 1 / intermediate layer 2 / sealing layer. It is preferable to provide an intermediate layer between the laminate layer and the sealing layer because peeling between the laminate layer and the sealing layer is less likely to occur and recycled raw materials can be easily used, and the raw material composition of the intermediate layer is preferably intermediate between that of the laminate layer and the sealing layer in order to make peeling between the laminate layer and the sealing layer less likely to occur.

[0043] The greater the difference in melt flow rate between the raw resins of adjacent layers and / or the greater the difference in melt flow rate between the raw resins mixed in each layer, the more poor the appearance. The ratio of the melt flow rates of the raw resins of adjacent layers is preferably 0.5 to 2.0. A melt flow rate ratio within this range is less likely to cause poor appearance, such as layer misalignment, blemishes, or unevenness. Furthermore, the main peak of the melting point of the laminated sealant film of the present invention is preferably 121°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, even more preferably 150°C or higher, and particularly preferably 160°C or higher. When the main peak of the melting point of the film is 121°C or higher, the suitability for high retort is further improved.

[0044] (Method for producing laminate sealant film) The method for producing the laminate sealant film of the present invention will be described in detail below, but is not limited thereto. The resin composition of the laminate layer and the seal layer may be prepared by blending the above-mentioned resin raw materials and, if necessary, various additives in a mixer such as a Henschel mixer, a Banbury mixer, or a tumbler mixer, and then pelletizing the mixture using a single- or twin-screw extruder to form a film. Alternatively, the components may be blended together and fed to a film-forming machine.

[0045] (Melt Extrusion Process) The mixed resin composition is melted, for example, at a resin temperature of 110 to 300°C, melt-extruded into a sheet from, for example, a T-die, cast onto a chill roll, and cooled and solidified to obtain an unstretched sheet. A preferred specific method for this is casting onto a chill roll. Multilayering can be achieved using a multilayering device such as a multilayer feed block, a static mixer, or a multi-manifold die. For example, resins delivered from different flow paths using two or more extruders are laminated into multiple layers using a multilayer feed block or a multi-manifold die. Examples of methods include melt-extruding a melt-kneaded laminated resin composition sheet and forming it into a film using a T-die method or an inflation method. However, the T-die method is particularly preferred because it allows for a high resin melt temperature.

[0046] (Cooling and Solidification Process) For example, it is preferable to cast a sheet melt-extruded from a T-die onto a chill roll and cool it. The lower limit of the chill roll temperature is preferably 10°C. If the temperature is lower than this, not only may the crystallization suppression effect saturate, but problems such as condensation may also occur, which is undesirable. The upper limit of the chill roll temperature is preferably 70°C or lower. If the temperature exceeds this range, crystallization will progress and transparency will deteriorate, which is undesirable. Furthermore, when the chill roll temperature is within the above range, it is preferable to reduce the humidity of the environment near the chill roll to prevent condensation. During casting, the surface temperature of the chill roll rises because the hot resin comes into contact with the surface. Typically, chill rolls are cooled by flowing cooling water through piping inside. However, it is necessary to reduce the temperature difference across the width of the chill roll surface by ensuring a sufficient amount of cooling water, optimizing the piping arrangement, and performing maintenance to prevent sludge from adhering to the piping. In this case, the thickness of the unstretched sheet is preferably in the range of 3 μm to 200 μm. The thickness of the film is preferably in the range of 5 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less.

[0047] (Film characteristics) The film characteristics of the present invention will be described. In the laminate sealant film of the present invention, the "longitudinal direction" is the direction corresponding to the flow direction in the film production process, and the "width direction" is the direction perpendicular to the flow direction in the film production process. Hereinafter, the "longitudinal direction" may be abbreviated as the "MD direction" and the "width direction" may be abbreviated as the "TD direction".

[0048] (Film Appearance) The laminated sealant film of the present invention is required to have general uniformity and excellent appearance. For example, it is desirable that the thickness variation is small, there are few fish eyes, foreign matter, streaks, scratches, color unevenness, wrinkles, and there are no pinholes. When measured by the method described in the examples, it is desirable that the number of foreign matter of 1 mm or more and less than 2 mm square is not detected in 10,000 m ２ It is preferable that there are less than 100 foreign matters per unit area, and it is more preferable that no foreign matter of 1 mm square or larger is detected.

[0049] (Haze) The haze of the laminate sealant film of the present invention is preferably 10% or less, more preferably 9% or less, even more preferably 8% or less, even more preferably 7% or less, and particularly preferably 5% or less. If the haze exceeds 10%, the film often has streaks or scratches, and the contents become difficult to see. The haze of the laminate sealant film of the present invention is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more. If the haze is 1% or more, the blocking strength is less likely to decrease.

[0050] (Static Friction Coefficient) The static friction coefficient of the laminate sealant film of the present invention between the sealing surfaces at a load of 0.5 kgf is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. If the static friction coefficient is 2.0 or more, the slipperiness between the films becomes insufficient, and the handling properties as a packaging material will not be satisfactory. Furthermore, the static friction coefficient of the laminate sealant film of the present invention between the sealing surfaces at a load of 1.5 kgf is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. If the static friction coefficient is 2.0 or more, the slipperiness between the films becomes insufficient, and the handling properties as a packaging material will not be satisfactory.

[0051] (Dynamic Friction Coefficient) The dynamic friction coefficient of the laminate sealant film of the present invention between the sealing surfaces at a load of 0.5 kgf is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. When the dynamic friction coefficient is 2.0 or more, the sliding property between the films becomes insufficient, and the handling properties as a packaging material are not satisfactory. Furthermore, the dynamic friction coefficient of the laminate sealant film of the present invention between the sealing surfaces at a load of 1.5 kgf is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. When the dynamic friction coefficient is 2.0 or less, the sliding property between the films is sufficient, and the handling properties as a packaging material are likely to be satisfactory.

[0052] (Scratch Resistance) In a friction test between the sealing surface and the laminate surface of the laminate sealant film of the present invention, the smaller the change in haze before and after treatment, the better the scratch resistance can be said to be. The change is preferably 3% or less, more preferably 2% or less, and particularly preferably 1% or less. Furthermore, the haze after a friction test between the sealing surface and the laminate surface of the laminate sealant film of the present invention is preferably 10% or less, more preferably 8% or less, even more preferably 6% or less, and particularly preferably 5% or less.

[0053] (Blocking strength) The blocking value of the laminated sealant film of the present invention is preferably 500 N / 15 mm or less. When the blocking value is 500 N / 15 mm or less, bag-making processing is easier. The blocking value is preferably 200 N / 15 mm or less, and more preferably 100 N / 15 mm or less.

[0054] (Tensile modulus) The tensile modulus in the longitudinal direction of the laminate sealant film of the present invention is preferably 200 MPa or more, more preferably 250 MPa or more, even more preferably 300 MPa or more, even more preferably 330 MPa or more, and particularly preferably 345 MPa or more. When the tensile modulus is 200 MPa or more, bag-making processing is easier. When the tensile modulus is 200 MPa or more, the tensile modulus in the width direction of the laminate sealant film of the present invention is preferably 200 MPa or more, more preferably 250 MPa or more, even more preferably 300 MPa or more, even more preferably 300 MPa or more, even more preferably 330 MPa or more, and particularly preferably 345 MPa or more. When the tensile modulus is 200 MPa or more, bag-making processing is easier.

[0055] (Ultimate Heat Seal Strength) The ultimate heat seal strength of the laminate sealant film of the present invention is preferably 10 N / 15 mm or more, more preferably 12 N / 15 mm or more, even more preferably 14 N / 15 mm or more, and particularly preferably 16 N / 15 mm or more. In the case of general packaging bags and the like, where the mass of the contents is large and a relatively high heat seal strength is required, a strength of 15 N / 15 mm or more is required.

[0056] The rate of variation in the ultimate heat seal strength of the laminate sealant film of the present invention is preferably 20% or less, more preferably 19% or less, even more preferably 17% or less, and particularly preferably 16% or less. One way to reduce the variation in the ultimate heat seal strength to 20% or less is to make it difficult for peeling to occur between the seal layer and the laminate layer of the laminate sealant film. The condition between the seal layer and the laminate layer can be confirmed by, for example, observing the cross section of the test piece with a microscope after measuring the ultimate heat seal strength.

[0057] (Heat sealing temperature) The heat sealing temperature is preferably 60°C or higher and 180°C or lower, more preferably 70°C or higher and 170°C or lower, and even more preferably 80°C or higher and 160°C or lower. The lower limit of the heat sealing temperature is preferably 20°C or higher than the lowest melting point of the polyethylene resin and / or polypropylene resin in the seal layer, and the upper limit is preferably 10°C or higher than the highest melting point of the polyethylene resin and / or polypropylene resin in the laminate layer. The low-temperature sealing effect of the heat sealing temperature is evaluated based on the degree of decrease in the heat sealing temperature, using the heat sealing temperature in Comparative Example 1 described below as a reference. The low-temperature sealability of the heat sealing temperature is preferably 5°C or higher, more preferably 10°C or higher, even more preferably 15°C or higher, even more preferably 22°C or higher, particularly preferably 25°C or higher, and most preferably 27°C or higher.

[0058] (Hot tack property) The hot tack property of the laminated sealant film of the present invention is desirably such that the tack peel distance is 20 mm or less at a lower temperature. Here, good hot tack property means that the seal strength between sealant films is sufficient even when the resin of the sealant film is in a molten state. The low-temperature sealing effect of hot tack property is evaluated by the degree of decrease in heat sealing temperature, based on the hot tack temperature in Comparative Example 1 described below. The low-temperature sealability of hot tack property is preferably 5°C or higher, more preferably 10°C or higher, even more preferably 15°C or higher, even more preferably 18°C ​​or higher, and particularly preferably 20°C or higher.

[0059] (Bag Breaking Strength) The bag breakage strength of the laminated sealant film of the present invention is evaluated using bags made from the laminated sealant film. When high burst strength is required, such as for containers for retort sterilization, the bursting strength is preferably 20 kPa or more, more preferably 23 Pa or more, and even more preferably 27 Pa or more. The low-temperature sealing effect of bag breakage strength is evaluated based on the temperature at which the bag breakage strength becomes 0 kPa, using the temperature at which the bag breakage strength becomes 0 kPa in Comparative Example 1 described below as the reference temperature. The low-temperature sealing effect of bag breakage strength is preferably 5°C or more, more preferably 10°C or more, even more preferably 15°C or more, and even more preferably 18°C ​​or more.

[0060] (Melting Point of Resin) The melting point of the resin was measured in accordance with JIS K7121 using a differential scanning calorimeter (Seiko Instruments Inc., DSC60). Specifically, about 5 mg of a sample was packed into an aluminum pan, heated from room temperature to 200°C at a heating / cooling rate of 10°C / min, held at 200°C for 3 minutes, cooled to 23°C, held at 23°C for 3 minutes, and then heated again to 200°C. The temperature of the highest melting endothermic peak was taken as the melting point. When there were two or more melting endothermic peaks, the highest melting endothermic peak was taken as the melting point.

[0061] (Melt Flow Rate) According to JIS K7112, polypropylene resins were measured at a temperature of 230°C, and polyethylene resins such as L-LDPE were measured at a temperature of 190°C using a thermal flow evaluation device (Shimadzu Corporation, Capillary Rheometer, CFT-500D).

[0062] (Average particle size of particles) Inorganic particles or polyethylene particles were dispersed in ion-exchanged water stirred at a predetermined rotation speed (about 5000 rpm) using a high-speed stirrer, and the resulting dispersion was added to Isotone (physiological saline) and further dispersed using an ultrasonic disperser. The particle size distribution was then determined by the Cole counter method, and the volume average particle size was calculated. The refractive indexes used were 1.30 for physiological saline, 1.457 for synthetic silica and diatomaceous earth, and 1.54 for polyethylene.

[0063] (Film Appearance 1) The film appearance is inspected for fisheyes, foreign matter, streaks, and scratches. Fisheyes, foreign matter, streaks, and scratches were evaluated using a defect detector (MaxEye.X Series, Hutec Corporation). The evaluation criteria are as follows: ◯: Can be used without problems. △: It is necessary to check the intended use, but it can be used without problems in most cases. ×: It may be usable with limited uses. Measurement conditions ◯: No fisheyes, foreign matter of 1 mm or more, streaks, or scratches were detected. △: The number of fisheyes, foreign matter of 1 mm or more and less than 2 mm square, streaks, and scratches detected was 10,000 m. ２ x: The number of fish eyes and foreign matter of 1 mm or more and less than 2 mm square, as well as streaks and scratches, detected was less than 100 per 10,000 m. ２ More than 100 foreign objects per unit area and / or foreign objects measuring 2 mm square or larger were detected. Note that the color of the foreign objects is not important here.

[0064] (Film Appearance 2) The film appearance was also evaluated by haze. (Haze) The haze of the laminate sealant film was measured using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., model: ZE2000) in accordance with JIS K8701. The laminated laminate sealant film was also measured in the same manner.

[0065] (Static Friction Coefficient, Dynamic Friction Coefficient) In accordance with JIS K7125, the dynamic friction coefficient and static friction coefficient were determined under the following conditions in an environment of 23°C and 65% RH. The load was 0.5 kgf or 1.5 kgf. The measurement surfaces were opposing seal surfaces, or seal surfaces and laminate surfaces. The measurement device used was a TENSILON STM-T-50BP manufactured by Toyo Baldwin Co., Ltd.

[0066] (Scratch Resistance) Measurement was performed according to the following procedure with reference to JIS K7316. First, the haze of the laminated sealant film was measured in advance. Next, a load of 20 g was applied to the flat friction element of a Gakushin-type abrasion tester (Yasuda Seiki Seisakusho Co., Ltd., friction tester type II, flat friction element 20 x 20 mm, flat test piece stand, sliding arc length 100 mm), and a 60 x 60 mm laminated sealant film was neatly placed on it and fixed with the attached jig. The same laminated sealant film was also placed on the test piece stand. Each film was set so that the sealant surface faced each other, as in the heat seal. Next, a friction test was performed 50 times back and forth (10 m), and then the haze was measured. Scratch resistance was evaluated by subtracting the haze before the friction test from the haze after the friction test.

[0067] (Blocking strength) was measured in accordance with ASTM-D-1893-67. First, a laminated sealant film (10 cm x 15 cm) was stacked with the measurement surfaces facing each other, and a 7 cm x 7 cm aluminum plate (2 mm thick) was placed on the film in a heat press (manufactured by Tester Sangyo Co., Ltd., model: SA-303) at the center of the sample width (10 cm) and 1 cm inside in the length direction (15 cm) so that the edge of the plate was aligned with the edge of the aluminum plate, and the film was then pressed at 50°C under a pressure of 440 kgf / cm. ２ The sample was subjected to a pressure treatment for 15 minutes at a pressure of 1000 kJ / s. Next, the sample blocked by this pressure treatment and an aluminum rod with a diameter of 6 mm were attached to an autograph (Shimadzu Corporation, Model: UA-3122), and the force required for the aluminum rod to peel off the blocked portion at a speed of 200 mm / min was measured. In this case, it was assumed that the aluminum rod and the peeled surface were horizontal. Four measurements were taken on the same sample, and the average value was shown.

[0068] (Tensile modulus) Measurement was performed in accordance with JIS K7127 under the following conditions: The tensile modulus in the machine direction (MD) and transverse direction (TD) of the film was measured three times with a sample length of 100 mm, a sample width of 15 mm, a chuck distance of 20 mm, and a speed of 200 mm / min, and the average value was taken as the tensile modulus in each direction.

[0069] (Preparation of Laminate) A laminate with a biaxially oriented polypropylene film (Pylen (registered trademark), P2161, 20 μm, manufactured by Toyobo Co., Ltd.) was prepared as follows. A dry laminating adhesive (TM569, CAT-10L, manufactured by Toyo-Morton Co., Ltd.) was applied to the corona surface of the biaxially oriented polypropylene film so as to give a solid content of 3 g / m2, and after the solvent was volatilized and removed in an oven at 80°C, the corona surface of the laminate sealant film and the adhesive-coated surface were nipped and laminated between temperature-controlled rolls at 60°C. This laminated laminate sealant film was left to stand at 40°C for 2 days.

[0070] (Attained heat seal strength) This was measured in accordance with JIS Z1707 under the following conditions. Laminated laminate sealant films, each with the laminate sealant surfaces facing each other, were heat-sealed using a 10 mm-wide seal bar with a test sealer (semi-automatic mouthpiece sealing machine, manufactured by Seibu Kikai Co., Ltd., TYB-300) at a sealing pressure of 0.2 MPa, a sealing time of 1.0 second, and heat seal temperatures of 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and 160°C, and then allowed to cool. The samples obtained with this test sealer were cut into strips with a heat seal width of 15 mm and placed in a tensile tester (manufactured by Instron, universal material testing machine, 5980 series), and the maximum strength at which the sealant surfaces were peeled off was measured at a speed of 200 mm / min. The measurement was carried out three times for each temperature, and the average value was taken as the heat seal strength at the heat seal temperature. The highest value among these heat seal strengths was taken as the achieved heat seal strength.

[0071] (Variation Rate of Final Heat Seal Strength) The variation rate of final heat seal strength is calculated by the following formula (1): Variation Rate of Final Heat Seal Strength = (Maximum Final Heat Seal Strength / Minimum Final Heat Seal Strength) / Average Final Heat Seal Strength × 100 (%) (1)

[0072] (Heat sealing temperature) Measurement was performed under the following conditions in accordance with JIS Z1707. Laminated laminate sealant films, each with the laminate sealant surfaces facing each other, were heat-sealed using a 10 mm-wide seal bar with a test sealer (semi-automatic mouthpiece sealing machine, manufactured by Seibu Kikai Co., Ltd., TYB-300) at a sealing pressure of 0.2 MPa, a sealing time of 1.0 second, and heat sealing temperatures of 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and 160°C, followed by cooling. Samples obtained with these test sealers were cut into strips with a heat seal width of 15 mm and placed in a tensile tester (manufactured by Instron, universal material testing machine, 5980 series), and the maximum strength at which the sealant surfaces were peeled off was measured at a speed of 200 mm / min. Measurement was carried out three times in total for each temperature, and the average value was taken as the heat seal strength at the heat seal temperature. The temperature at which the heat seal strength reached 10 N / 15 mm was taken as the heat seal temperature.

[0073] (Low-temperature sealing effect of heat-sealing temperature) The low-temperature sealing effect of the heat-sealing temperature was evaluated by the difference in heat-sealing temperature (°C) based on the heat-sealing temperature in Comparative Example 1 described below. Specifically, the low-temperature sealability evaluation for Example 1 and Comparative Example 7 was as follows: (heat-sealing temperature in Comparative Example 1: 135°C) - (heat-sealing temperature in Example 1: 115°C) = 20°C, and (heat-sealing temperature in Comparative Example 1: 135°C) - (heat-sealing temperature in Comparative Example 17: 135°C) = 0°C.

[0074] (Hot tack temperature) The laminates were stacked with the sealant surfaces facing each other, and subjected to a pressure of 2 kg / cm at temperatures of 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and 160°C. ２ After heat sealing for 1 second at a pressure of 1000 kJ / s, a load of 46 g was applied and the distance the sealed portion peeled off was measured. The device used was a HEAT SEAL TESTER, TP-701-B, manufactured by Tester Sangyo Co., Ltd. The temperature at which the sealed portion peeled off the distance was 20 mm was defined as the hot tack temperature.

[0075] (Low-temperature sealing effect of hot tack temperature) The low-temperature sealing effect of the hot tack temperature is evaluated by the difference in hot tack temperature (°C) based on the hot tack temperature in Comparative Example 1 described below. Specifically, the low-temperature sealing effect evaluations for Example 1 and Comparative Example 7 are (hot tack temperature in Comparative Example 1: 128°C) - (hot tack temperature in Example 1: 118°C) = 10°C, and (hot tack temperature in Comparative Example 1: 118°C) - (heat sealing temperature in Comparative Example 7: 135°C) = -7°C.

[0076] (Bag Breaking Strength) Using a horizontal pillow packaging machine (Fujikikai Co., Ltd., FW3301 II / B BD100), the cut length was 250 mm, the height was 45 mm, and the rotation speed was 40 rpm. The temperature of the center seal portion was lowered from 160°C in 10°C intervals, and the temperature of the end seal portion was fixed at 140°C. Bags were also made using a sponge scrubber (Kikuron Co., Ltd., Kikuron A (size: 75 x 115 x 36 mm)) as the contents. Evaluation was performed by visual appearance and burst strength (JIS Z0238 Test method for heat-sealed flexible packaging bags and semi-rigid containers). Burst strength was measured using a seal strength / burst strength measuring device (Sun Scientific Co., Ltd., SEAL TESTER, FKT-100-J).

[0077] (Low-Temperature Sealability of Bag Breaking Strength) The low-temperature sealability of bag breakage strength is evaluated by the difference (°C) between the temperature at which the bag breakage strength becomes 0 kPa and the temperature at which the bag breakage strength becomes 0 kPa in Comparative Example 1 described below. Specifically, the evaluation of the low-temperature sealability of bag breakage strength for Example 1 and Comparative Example 7 is as follows: (Temperature at which the bag breakage strength becomes 0 kPa in Comparative Example 1: 110°C) - (Temperature at which the bag breakage strength becomes 0 kPa in Example 1: 100°C) = 10°C, (Temperature at which the bag breakage strength becomes 0 kPa in Comparative Example 1: 110°C) - (Temperature at which the bag breakage strength becomes 0 kPa in Comparative Example 7: 130°C) = -20°C.

[0078] (Propylene-based copolymers) PP-1: FL6745A (manufactured by Sumitomo Chemical Co., Ltd., Noblene (registered trademark), propylene-ethylene-butene random copolymer, melting point 132°C, melt flow rate 6.0g / 10min) PP-2: F744NP (manufactured by Prime Polymer Co., Ltd., Prime Polypro (registered trademark), ethylene-propylene random copolymer, melting point 133°C, melt flow rate 7.0g / 10min) PP-3: FS2011DG3 (manufactured by Sumitomo Chemical Co., Ltd., Noblene (registered trademark), propylene random copolymer, melting point 158°C, melt flow rate 2.5g / 10min) PP-4: WF893R9 (manufactured by Sumitomo Chemical Co., Ltd., Noblene (registered trademark), propylene random copolymer, melting point 137°C, melt flow rate 7.0g / 10min) PP-5: FLX64G2 (manufactured by Sumitomo Chemical Co., Ltd., Noblen (registered trademark), propylene-ethylene-butene random copolymer, melting point 138°C, melt flow rate 7.0 g / 10 min) PP-6: F-201SPB (manufactured by Prime Polymer Co., Ltd., Prime Polypro (registered trademark), propylene-random copolymer, melting point 160°C, melt flow rate 2.0 g / 10 min)

[0079] (Ethylene-based polymers) PE-1: FV401 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark) E, linear low-density polyethylene resin, melting point 112°C, melt flow rate 3.8g / 10min) PE-2: FV402 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark) E, linear low-density polyethylene resin, melting point 115°C, melt flow rate 3.8g / 10min) PE-3: FV403 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark) E, linear low-density polyethylene resin, melting point 117°C, melt flow rate 3.8g / 10min) PE-4: FV405 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark) E, linear low-density polyethylene resin, melting point 118°C, melt flow rate 3.8g / 10min) PE-5: FV407 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark) E, linear low-density polyethylene resin, melting point 124°C, melt flow rate 3.2g / 10min) PE-6: FV104 (manufactured by Sumitomo Chemical Co., Ltd., Sumikathene (registered trademark), linear low-density polyethylene resin, melting point 121°C, melt flow rate 1.0g / 10min) PE-7: 3600F (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark), high-density polyethylene resin, melting point 133°C, melt flow rate 1.0g / 10min) PE-8: 031GLD (manufactured by Ube Maruzen Polyethylene Co., Ltd., Yumerit (registered trademark), linear low-density polyethylene resin, melting point 100°C, melt flow rate 10.0g / 10min) PE-9: M12P (manufactured by Mitsui Chemicals, Inc., Ultzex ​​(registered trademark), low-density polyethylene resin, melting point 114°C, melt flow rate 3.0 g / 10 min)

[0080] (Anti-blocking agent) Synthetic silica: KMP130-2 (average particle size 2 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) Diatomaceous earth: Dicalite WF (average particle size 4 μm, manufactured by Grefco. Inc.) Ultra-high molecular weight polyethylene particles: PM200 (average particle size 10 μm, manufactured by Mitsui Chemicals, Inc.)

[0081] (Organic lubricants) Erucamide: Brand name Diamid L-200 (melting point 81°C, manufactured by Mitsubishi Chemical Corporation) Behenic amide: Brand name D1007 (melting point 110°C, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0082] (Masterbatches) 1) Silica masterbatch: Silica (KMP-130-2, manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 2 μm) was mixed with Noblen (registered trademark) FL6745 manufactured by Sumitomo Chemical Co., Ltd. to prepare a masterbatch containing 15% by weight of silica. 2) Diatomaceous earth masterbatch: Diatomaceous earth (Dicalite WF, manufactured by Grefco. Inc., average particle size 4 μm) was mixed with Noblen (registered trademark) FL6745 manufactured by Sumitomo Chemical Co., Ltd. to prepare a masterbatch containing 12% by weight of diatomaceous earth. 3) Ultra-high molecular weight polyethylene particle masterbatch: Ultra-high molecular weight polyethylene particles (Mipelon PM200, manufactured by Mitsui Chemicals, Inc., average particle size 10 μm) were mixed with Noblen (registered trademark) FL6745 manufactured by Sumitomo Chemical Co., Ltd. to prepare a masterbatch containing 10% by weight of ultra-high molecular weight polyethylene particles. 4) Erucamide masterbatch: A masterbatch containing 5% by weight of erucamide was prepared by mixing erucamide with Noblen (registered trademark) FL6745 manufactured by Sumitomo Chemical Co., Ltd. 5) Behenamide masterbatch: A masterbatch containing 2% by weight of behenamide was prepared by mixing behenamide with Noblen (registered trademark) FL6745 manufactured by Sumitomo Chemical Co., Ltd.

[0083] (Examples 1 to 6) The laminate layer and intermediate layer were made from FL6745A. The seal layer was made from the resins and additives shown in Table 1. Using three extruders, each was melted at 240°C, filtered through a sintered filter with a filtration accuracy of 60 μm, and co-extruded into a sheet from a T-die. The laminate layer, intermediate layer, and seal layer were melt-extruded to a thickness ratio of 25:50:25 vol.%, cooled and solidified on a cooling roll at 30°C, and then wound into a roll at a speed of 20 m / min to obtain a laminate sealant film with a thickness of 30 μm and a laminate layer wet tension of 45 mN / m. The evaluation results are shown in Table 1.

[0084] The laminated sealant films obtained in Examples 1 to 6 had excellent low-temperature sealing properties and hot tack, stable blocking resistance and friction coefficient, and good appearance and scratch resistance. Of course, there were no problems with film-forming processability, and sufficient burst strength was obtained. In particular, Example 4 had excellent scratch resistance.

[0085] Examples 7-11: The laminate layer was made from FL8115, and the intermediate layer from FL6745A. The seal layer was made from the resins and additives shown in Table 2. Using three extruders, each was melted at 240°C, filtered through a sintered filter with a filtration accuracy of 60 μm, and co-extruded into a sheet from a T-die. The laminate layer, intermediate layer, and seal layer were melt-extruded to a thickness ratio of 25:50:25 vol.%, cooled and solidified on a cooling roll at 30°C, and then wound into a roll at a speed of 20 m / min. A laminate sealant film with a thickness of 30 μm and a laminate layer wet tension of 45 mN / m was obtained. The evaluation results are shown in Table 2.

[0086] The laminated sealant films obtained in Examples 7 to 11 had excellent low-temperature sealing properties and hot tack, stable blocking resistance and friction coefficient, and good appearance and scratch resistance. Of course, there were no problems with film-forming processability, and sufficient burst strength was obtained.

[0087] (Example 12) The laminate layer and intermediate layer were made from FL8115. The sealing layer was made from the resins and additives shown in Table 2. Using three extruders, each was melted at 240°C, filtered through a sintered filter with a filtration accuracy of 60 μm, and co-extruded into a sheet from a T-die. The laminate layer, intermediate layer, and sealing layer were melt-extruded to a thickness ratio of 20:60:20 vol.%, cooled and solidified on a cooling roll at 30°C, and then wound into a roll at a speed of 20 m / min to obtain a laminate sealant film with a thickness of 30 μm and a laminate layer wet tension of 45 mN / m. The evaluation results are shown in Table 2.

[0088] The laminated sealant film obtained in Example 12 had excellent low-temperature sealing properties and hot tack, stable blocking resistance and friction coefficient, and good appearance and scratch resistance. Of course, there were no problems with film-forming processability, and sufficient burst strength was obtained.

[0089] (Comparative Examples 1 to 10) In the same manner as in Example 1, polypropylene-based resin films were obtained using the resins and additives shown in Tables 3 and 4 as raw materials. The evaluation results are shown in Tables 3 and 4. The film obtained in Comparative Example 1 was poor in low-temperature sealability in terms of heat sealing temperature, hot tack property, and bag-breaking strength. The film obtained in Comparative Example 2 was poor in low-temperature sealability in terms of heat sealing temperature, hot tack property, and bag-breaking strength. The film obtained in Comparative Example 3 was poor in slipperiness and had variable heat-sealing temperatures, resulting in insufficient bag-forming properties. The film obtained in Comparative Example 4 was poor in low-temperature sealability in terms of bag-breaking strength. The film obtained in Comparative Example 5 was poor in low-temperature sealability in terms of bag-breaking strength. The film obtained in Comparative Example 6 was poor in appearance. The film obtained in Comparative Example 7 was poor in low-temperature sealability in terms of appearance and bag-breaking strength. The film obtained in Comparative Example 8 was poor in ultimate heat-sealing strength, blocking resistance, and scratch resistance. The films obtained in Comparative Examples 9 and 10 were inferior in the ultimate heat seal strength, blocking resistance, scratch resistance, and low-temperature sealability of bag strength.

[0090]

[0091]

[0092]

[0093]

[0094] The laminated sealant film of the present invention has excellent low-temperature bag-forming properties and is therefore suitable as a packaging material for many products, such as foods, beverages, pharmaceuticals, and chemicals. In particular, it can be suitably used as a material for automatically forming pillow packaging bags, gusset packaging bags, three-side seal packaging bags, and other bags while packaging the contents.

Claims

1. A laminated sealant film that satisfies all of the following requirements 1) to 8). 1) A laminated sealant film including at least a laminate layer and a seal layer. 2) The laminate layer is made of a resin composition containing a polypropylene-based resin as a main component. 3) The sealing layer is made of a resin composition containing as its main component a mixture of a polypropylene resin and a polyethylene resin having a melting point of 100° C. or higher. 4) The seal layer contains 1% by weight or more and 90% by weight or less of polypropylene resin and 10% by weight or more and 99% by weight or less of polyethylene resin, based on 100% by weight of the mixture of polypropylene resin and polyethylene resin constituting the seal layer. 5) The polyethylene resin constituting the sealing layer contains 90% by weight or more of a straight-chain linear polyethylene resin. 6) The difference in melting point between the polypropylene resin and the linear polyethylene resin in the sealing layer is 15° C. or more. 7) The ratio of the melt flow rate of the polypropylene resin to the melt flow rate of the linear polyethylene resin in the seal layer is 0.5 or more and 1.8 or less. 8) The polypropylene resin and the linear polyethylene resin in the sealing layer have a melt flow rate of 9 g / 10 min or less.

2. 2. The laminate sealant film according to claim 1, wherein the polypropylene resin is a propylene random copolymer.

3. 3. The laminate sealant film according to claim 1 or 2, wherein the film has a main peak of melting point of 120° C. or higher.

4. 3. The laminate sealant film according to claim 1, wherein the static friction coefficient between sealing surfaces is 0.5 or less.

5. 3. The laminate sealant film according to claim 1, wherein the coefficient of dynamic friction between sealing surfaces is 0.5 or less.

6. 3. The laminate sealant film according to claim 1 or 2, wherein the sealing layer comprises organic particles as an antiblocking agent.

7. 3. The laminate sealant film according to claim 1, wherein the sealing layer contains two or more kinds of fatty acid amides as organic lubricants.