Sealant film
A resin composition of polypropylene, polyethylene, and silylated polyolefin addresses content sticking and inadequate heat sealing in packaging films by enhancing easy peelability and liquid repellency, ensuring effective and hygienic removal of viscous substances.
Patent Information
- Application Number
- JP2025012336
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2025-01-28
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2040-08-21
AI Technical Summary
Existing packaging films face issues with contents sticking to the inner surface, difficulty in removal, especially with viscous substances, and inadequate heat sealing and liquid repellency, leading to hygiene problems and reduced seal strength.
A resin composition containing polypropylene, polyethylene, and silylated polyolefin, with specific weight ratios and properties, is used to create a sealing layer that balances heat sealing, easy peelability, and liquid repellency.
The film allows easy removal of contents, maintains heat sealing properties, and exhibits excellent slip and anti-blocking characteristics, even with viscous substances.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a sealant film and a laminate using the same. More specifically, the present invention relates to a sealant film that is excellent in liquid repellency, heat sealing properties, slip properties, and anti-blocking properties, and to a laminate packaging bag using the same. [Background technology]
[0002] Packaging bags made of plastic film are lightweight, airtight, transparent, strong, and easy to handle, and are therefore widely used to package foods, medicines, and other solid, liquid, powder, paste, viscous substances, and mixtures thereof.
[0003] However, it is well known from experience that when removing food, medicine, or other sticky contents from a packaging bag, they tend to stick to the inner surface of the bag, making them difficult to remove. Furthermore, discarding a packaging bag with remaining contents can pose a hygiene problem.
[0004] To solve these problems, films with a surfactant applied to the surface or films with a surfactant kneaded into them have been proposed (see, for example, Patent Documents 1 and 2). However, these films have problems such as making it difficult to remove the contents and reducing the heat seal strength.
[0005] Furthermore, films containing silicone resin or silicone oil and having improved liquid repellency have been proposed (see, for example, Patent Documents 3 and 4), but the liquid repellency is also insufficient.
[0006] Furthermore, films made of silylated polyolefins and having improved liquid repellency have also been proposed (see, for example, Patent Documents 5, 6, and 7). Additionally, a film has been proposed in which polyethylene resin is mixed with polypropylene resin to impart easy peelability, but the liquid repellency is insufficient (see, for example, Patent Document 8). [Prior art documents] [Patent documents]
[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-355362 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-48229 [Patent Document 3] Japanese Patent Application Publication No. 08-337267 [Patent Document 4] Patent No. 3539723 [Patent Document 5] Patent No. 5990131 [Patent Document 6] Japanese Patent Application Laid-Open No. 2014-177541 [Patent Document 7] Japanese Patent Application Laid-Open No. 2015-024548 [Patent Document 8] Patent No. 5394096 Summary of the Invention [Problem to be solved by the invention]
[0008] The present invention has been made in consideration of the above technical background, and aims to provide a film and / or a packaging bag that is easy to remove from the packaging bag even if the contents are viscous, exhibits sufficient heat sealing properties, and exhibits excellent easy-peel properties. [Means for solving the problem]
[0009] In view of the above circumstances, the present inventors have conducted extensive research and have found that the above problems can be solved by using a resin composition containing a polypropylene resin and a silylated polyolefin, and by setting the temperature dependency of the heat seal strength of a layer made of this resin composition within a specific range, thereby completing the present invention. That is, the present invention is a film for sealant use that includes a sealing layer made of a resin composition containing the following (a), (b), and (c), and that satisfies the following (1), (2), and (3): (a) Polypropylene resin (b) Polyethylene resin (c) Silylated polyethylene resin (1) The contents of (a), (b), and (c) are 30 to 70% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, based on the total weight of the resin composition. (2) Silylated polyethylene resin is represented by the following formula: CH3-(CH2) n-2 -CH2-S i (CH3)2O-(-S i (CH3)2-O-) d -S i (CH3)2-CH2-(CH2) n-2 -CH3 (In the formula, d is an integer of 1 or more, and n is an integer of 100 or more.) (3) The polyethylene resin is at least one polyethylene resin selected from the group consisting of high-pressure low-density polyethylene and linear low-density polyethylene.
[0010] Alternatively, the film is a film for sealant comprising a sealing layer made of a resin composition containing the following (a), (b), and (c), and satisfies the following (4), (5), and (6): (a) Polypropylene resin (b) Polyethylene resin (c) Silylated polyethylene resin (4) The contents of (a), (b), and (c) are 30 to 85% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, based on the total weight of the resin composition. (5) Silylated polyethylene resin is represented by the following formula: CH3-(CH2) n-2 -CH2-S i (CH3)2O-(-S i (CH3)2-O-) d -S i (CH3)2-CH2-(CH2) n-2 -CH3 (In the formula, d is an integer of 1 or more, and n is an integer of 100 or more.) (6) The polyethylene resin is an elastomer made of a copolymer of ethylene monomer and α-olefin.
[0011] In these cases, it is preferable that the resin composition contains particles made of an inorganic oxide or a synthetic resin.
[0012] Furthermore, in these cases, it is preferable that the resin composition contains (d) a fatty acid ester or a fatty acid amide.
[0013] In these cases, it is preferable to satisfy the following (7) and (8): (7) The ratio of silicon atoms Si to carbon atoms C contained in the sealing layer (S i / C) is 0.001 or more and 0.02 or less. (8) The ratio of silicon atoms Si to carbon atoms C on the surface of the sealing layer (S i / C) is 0.05 or more and 0.2 or less.
[0014] Furthermore, in these cases, it is preferable to satisfy the following (9): (9) Silicon atoms S contained in the sealing layer i and the abundance ratio of carbon atoms (S i / C) silicon atoms S on the surface of the sealing layer i and the abundance ratio of carbon atoms (S i / C) ratio is 2 or more.
[0015] Furthermore, in these cases, it is preferable that the blocking value of the surface of the sealing layer is 200 mN / 70 mm or less.
[0016] Furthermore, a laminate comprising the sealant film and a base film is preferred. [Effects of the Invention]
[0017] The present invention provides a packaging bag that allows easy removal of contents even when the contents are paste-like, viscous, or other sticky, and also provides a sealant film and a laminate thereof that have good heat sealing properties as well as excellent slip properties and blocking resistance. [Brief explanation of the drawings]
[0018] [Figure 1] Average Si concentration and surface Si concentration of the films described in Comparative Examples 1 and 4, Examples 2 to 4, and 13 [Figure 2] Schematic diagram of the procedure for liquid repellency evaluation [Figure 3] EDX mapping measurement photograph of film surface [Figure 4] TEM observation photograph of film cross section [Figure 5] Photo of the area around the die nozzle of a resin extruder DETAILED DESCRIPTION OF THE INVENTION
[0019] (Sealing layer) In the present invention, the resin composition constituting the sealing layer must contain (a) a polypropylene-based resin, (b) a polyethylene-based resin, and (c) a silylated polyolefin resin.
[0020] (Polypropylene resin) The polypropylene resin used in the present invention is a homopolymer of a propylene monomer, a random copolymer and / or a block copolymer of a propylene monomer and an α-olefin, or a mixture thereof. Examples of the α-olefin include ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, octene-1, and decene-1.
[0021] The polypropylene resin used is preferably a homopolypropylene or a polypropylene random copolymer, and more preferably a polypropylene-α-olefin random copolymer, which is a random copolymer of 85% by weight or more of propylene and 15% by weight or less of an α-olefin. As the α-olefin monomer for obtaining such a polypropylene random copolymer, ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, etc. can be used, but from the viewpoint of productivity, ethylene and butene-1 are particularly preferred. The α-olefin used for copolymerization may be at least one type, and if necessary, two or more types can be mixed and used.
[0022] The peak melting point of the polypropylene resin is preferably 130°C or higher. The melting point is measured by the method described in the Examples below. When the melting point peak temperature of the polypropylene resin is 130°C or higher, the shape of the package is less likely to collapse, the film can be conveyed more smoothly during high-speed packaging processing, and the resulting bag is less likely to wrinkle. In addition, retort processing or semi-retort processing is also possible.
[0023] The lower limit of the density of the polypropylene resin is preferably 880 kg / cm 3 and more preferably 885 kg / cm 3 880kg / cm 3 The upper limit of the density of the polypropylene resin added to the sealing layer is preferably 920 kg / cm. 3 and more preferably 900 kg / cm 3 920kg / cm 3 It is preferable that the thickness is not more than 100 μm, since it is possible to achieve both heat resistance and heat sealability.
[0024] The lower limit of the melt flow rate (MFR) of the polypropylene resin is preferably 2.0 g / 10 min, more preferably 2.5 g / 10 min, and even more preferably 2.7 g / 10 min. If it is 2.0 g / 10 min or more, the polypropylene resin and the polyethylene resin tend to be finely dispersed without layer separation, and the peel strength between the seal layers after heat sealing does not decrease too much. The upper limit of the melt flow rate of the polypropylene resin is preferably 10.0 g / 10 min, more preferably 8.0 g / 10 min, and even more preferably 7.0 g / 10 min. If the melt flow rate is 10.0 g / 10 min or less, the polypropylene and polyethylene resin are not compatible with each other and tend to be finely dispersed, and the peel strength between the seal layers after heat sealing is not excessively reduced.
[0025] (Polyethylene resin) The polyethylene resin used in the present invention is a copolymer of an ethylene monomer and an α-olefin. Examples of the α-olefin include propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, decene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. The copolymer of ethylene monomer and α-olefin referred to here is generally also called high-pressure low-density polyethylene, linear low-density polyethylene, or polyethylene-based elastomer. Elastomer refers to an olefin-based thermoplastic copolymer that exhibits rubber-like elasticity around room temperature. The melting points of high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polyethylene-based elastomer are preferably in the range of 50 to 140°C.
[0026] In the present invention, the density range of the raw polyethylene resin used for blending is 850 to 970 kg / m 3 is preferable, and 860 to 965 kg / m 3 More preferably, 865 to 960 kg / m 3 More preferably, the density is 850 kg / m 3 The above polyethylene resin does not reduce the peel strength between the sealing layers after heat sealing. The density is 970 kg / m 3 The following polyethylene resins also do not reduce the peel strength between the seal layers after heat sealing and are easy to polymerize.
[0027] The lower limit of the melt flow rate (MFR) of the polyethylene resin is preferably 0.6 g / 10 min, more preferably 1.0 g / 10 min, and even more preferably 1.5 g / 10 min. If it is 0.6 g / 10 min or more, fine dispersion of the polypropylene and polyethylene resin is easily achieved, and the peel strength between the seal layers after heat sealing is not excessively reduced. The upper limit of the melt flow rate of the polyethylene resin is preferably 5.0 g / 10 min, more preferably 4.0 g / 10 min, even more preferably 3.5 g / 10 min, and particularly preferably 3.0 g / 10 min or less. If it is 5.0 g / 10 min or less, fine dispersion of the polypropylene and polyethylene resin is likely to be achieved, which tends to reduce the peel strength between the seal layers after heat sealing.
[0028] When the polypropylene-based resin and polyethylene-based resin are blended and melted, a finely dispersed state can be created, which can reduce the strength at the time of peeling after heat sealing between the sealing layers or between the sealing layer and the periphery of the opening of another container component.
[0029] After heat sealing between seal layers or between a seal layer and the periphery of the opening of another container component, peel strength tends to decrease in the following order: ethylene copolymer (polyethylene elastomer), LLDPE, LDPE. The reason for this is presumably that ethylene copolymers are incompatible with polypropylene resins only in the ethylene portion, while LLDPE has side chains that allow for fine dispersion, and LDPE has long side chains that allow for strong fine dispersion.
[0030] Specifically, density 885 kg / m 3 , ethylene-butene copolymer elastomer (Tafmer A1085S manufactured by Mitsui Chemicals, Inc.) with MFR (230°C, 2.16 kg) of 2.2 g / 10 min, and density of 869 kg / m 3 An example of such a polymer is an ethylene-propylene copolymer elastomer (Tafmer P0480 manufactured by Mitsui Chemicals, Inc.) having a MFR (230°C, 2.16 kg) of 1.8 g / 10 min.
[0031] (Silylated polyolefin resin) The silylated polyolefin resin used in the present invention has S in the molecule. i It is obtained by reacting a silicon-containing compound having two or more H groups with a vinyl group-containing compound, which is a polymer of at least one olefin selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, and 1-hexene and contains vinyl groups at its terminals.
[0032] S i Examples of silicon-containing compounds having two or more H groups include methylhydrogenpolysiloxanes represented by formula (1) and compounds of formula (1) in which some or all of the methyl groups have been substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. Formula (1) (CH3)3S i O-(-S i H(CH3)-O-) a -S i (CH3)3 (In formula (1), a is an integer of 2 or more, and the upper limit is preferably 1000, more preferably 300, and even more preferably 50.)
[0033] S i Other examples of silicon-containing compounds having two or more H groups include dimethylsiloxane-methylhydrogensiloxane copolymers represented by formula (2), and compounds of formula (2) in which some or all of the methyl groups have been substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. Formula (2) (CH3)3S i O-(-S i (CH3)2-O-) b -(-S i H(CH3)-O-) c -S i (CH3)3 (In formula (2), b is an integer of 1 or more, c is an integer of 2 or more, and the upper limit of the total of b and c is preferably 1000, more preferably 300, and even more preferably 50.) In formula (2), -S i (CH3)2-O- unit and -S i The order in which the H(CH3)-O- units are arranged is not particularly limited, and they may be block-like, disordered, or statistically random.
[0034] S i Further examples of silicon-containing compounds having two or more H groups include methylhydrogenpolysiloxanes represented by formula (3) and compounds of formula (3) in which some or all of the methyl groups have been substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. Formula (3) HS i (CH3)2O-(-S i (CH3)2-O-) d -S i (CH3)2H (In formula (3), d is an integer of 1 or more, and the upper limit is preferably 1000, more preferably 300, and even more preferably 50.)
[0035] More specifically, such compounds include compounds whose structures corresponding to their number average molecular weights correspond to the structures shown below, but are not limited to these. HS i (CH3)2O-(-S i (CH3)2-O-)5-S i (CH3)2H HS i (CH3)2O-(-S i (CH3)2-O-)8-S i (CH3)2H HS i (CH3)2O-(-S i (CH3)2-O-) 18 -S i (CH3)2H HS i (CH3)2O-(-S i (CH3)2-O-)80 -S i (CH3)2H HS i (CH3)2O-(-S i (CH3)2-O-) 230 -S i (CH3)2H
[0036] (vinyl group-containing compound) The vinyl group-containing compound used in the present invention is obtained by copolymerizing or polymerizing at least one olefin selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, and 1-hexene.
[0037] The vinyl group-containing compound is preferably an ethylene-α-olefin copolymer containing 81 to 100 mol% of ethylene-derived structural units and 0 to 19 mol% of C3 to C20 α-olefin-derived structural units. More preferably, it is an ethylene-α-olefin copolymer containing 90 to 100 mol% of ethylene-derived structural units and 0 to 10 mol% of C3 to C20 α-olefin-derived structural units. It is particularly preferred that the ethylene-derived structural units are 100 mol%.
[0038] Furthermore, the vinyl group-containing compound preferably has a molecular weight distribution (ratio of weight average molecular weight to number average molecular weight, Mw / Mn) measured by gel permeation chromatography (GPC) in the range of 1.1 to 3.0.
[0039] The vinyl group-containing compound preferably has a number average molecular weight (Mn) in the range of 100 to 500,000, more preferably 500 to 300,000, and even more preferably 1,500 to 100,000.
[0040] The vinyl group-containing compound preferably has a melting point of 70° C. or higher and 130° C. or lower. The number average molecular weight of the vinyl group-containing compound of the present invention, determined by GPC, is preferably 100 or higher and 500,000 or lower, more preferably 500 or higher and 300,000 or lower, and even more preferably 1,500 or higher and 100,000 or lower.
[0041] The vinyl group of the vinyl group-containing compound is preferably present at the terminal of the main chain, and more preferably present only at the terminal of the main chain.
[0042] In addition, when the vinyl group-containing compound contains a vinyl group only at the end of the main chain, 1 The percentage of terminal unsaturation calculated by H-NMR is 80 mol % or more and 99.5 mol % or less, more preferably 90 mol % or more and 99 mol % or less.
[0043] (Method of producing silylated polyolefin resin) The silylated polyolefin resin used in the present invention is a silylated polyolefin resin or a derivative thereof, or a mixture thereof, obtained by reacting the above-mentioned vinyl group-containing compound with a silicon-containing compound in the presence of a transition metal catalyst according to the method described in JP 2014-223752 A.
[0044] Specific examples of silylated polyolefin resins include those having structures represented by formulas (4) to (6), but the combinations of silicon-containing compounds and vinyl group-containing compounds are not limited to these examples.
[0045] Formula (4) (CH3)3S i O-(-S i [CH2-(CH2) n-2 -CH3](CH3)-O-) a -Si(CH3)3 (In formula (4), a is an integer of 2 or more, and the upper limit is preferably 1000, more preferably 300, and even more preferably 50.)
[0046] Formula (5) (CH3)3S i O-(-S i (CH3)2-O-) b -(-S i [CH2-(CH2) n-2 -CH3](CH3)-O-) c -S i (CH3)3 (In formula (5), b is an integer of 1 or more, c is an integer of 2 or more, and the upper limit of the total of b and c is preferably 1000, more preferably 300, and even more preferably 50.)
[0047] Formula (6) CH3-(CH2) n-2 -CH2-S i (CH3)2O-(-S i (CH3)2-O-) d -S i (CH3)2-CH2-(CH2) n-2 -CH3 (In formula (6), d is an integer of 1 or more, and the upper limit is preferably 1000, further preferably 300, further preferably 50, and particularly preferably 25.)
[0048] The silylated polyolefin resin used in the present invention preferably contains 80% by weight or more, and particularly preferably 90% by weight or more, of a block copolymer in which both ends of polydimethylsiloxane are polyethylene, as represented by formula (6). In formula (6), d is preferably an integer of 3 or more, and more preferably 10 or more. In the formulas (4) to (6), n is preferably an integer of 100 or more, and more preferably 150 or more.
[0049] The silylated polyolefin resin used in the present invention preferably satisfies the following i) and ii) in order to obtain the properties of the film of the present invention and in order to produce the film of the present invention, more preferably satisfies the following i) to iii), and even more preferably satisfies the following i) to iv). i) Density is 900-1000 kg / m 3 The range is. ii) The melting point is in the range of 100 to 140°C. iii) The number average molecular weight is in the range of 1,000 to 20,000. iv) The copolymerization rate of silicone is in the range of 1 to 50% by weight. The chemical formula and molecular weight of the silylated polyolefin resin are identified by the method described in the Examples.
[0050] (Resin composition) When the polyethylene is LDPE or LLDPE, the contents of (a) polypropylene-based resin, (b) polyethylene-based resin, and (c) silylated polyolefin resin in the resin composition constituting the sealing layer must be 30 to 70% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, relative to the total resin composition. (a) The content of the polypropylene resin in the resin composition is more preferably 35% by weight or more, even more preferably 40% by weight or more, and particularly preferably 55% by weight or more. (a) When the polypropylene resin is contained in an amount of 30% by weight or more, the firmness is maintained. The content of the polypropylene resin in the resin composition is more preferably 65% by weight or less, and even more preferably 60% by weight or less. (a) When the content of the polypropylene resin is 70% by weight or less, easy peel property is observed. (b) The content of the polyethylene resin in the resin composition is more preferably 12% by weight or more, even more preferably 15% by weight or more, and particularly preferably 20% by weight or more. If the polyethylene resin content is 10% by weight or more, the peel strength between the seal layers after heat sealing is likely to decrease. The content of (b) polyethylene resin in the resin composition is more preferably 35% by weight or less, more preferably 30% by weight or less, and even more preferably 20% by weight or less. When the content of (b) polyethylene resin is about 40% by weight, the heat resistance is less likely to decrease. (c) The content of the silylated polyolefin resin in the resin composition is more preferably 5% by weight or more, even more preferably 7% by weight or more, and particularly preferably 12% by weight or more. When the silylated polyolefin resin is contained in an amount of 3% by weight or more, sufficient liquid repellency is obtained, and the liquid repellency against edible oils is particularly excellent. The content of (c) silylated polyolefin resin in the resin composition is more preferably 28% by weight or less, even more preferably 25% by weight or less, even more preferably 20% by weight or less, and even more preferably 15% by weight or less. A content of (c) silylated polyolefin resin of about 30% by weight does not significantly improve the liquid repellency effect. A lower content of (c) silylated polyolefin resin results in less segregation on the surface of the sealing layer.
[0051] When the polyethylene-based resin is an elastomer, the contents of (a) polypropylene-based resin, (b) polyethylene-based resin, and (c) silylated polyolefin resin in the resin composition constituting the sealing layer must be 30 to 85% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, relative to the total resin composition. (a) The content of the polypropylene resin in the resin composition is more preferably 35% by weight or more, even more preferably 40% by weight or more, and particularly preferably 55% by weight or more. (a) When the polypropylene resin is contained in an amount of 30% by weight or more, the firmness is maintained. The content of the polypropylene resin in the resin composition is more preferably 80% by weight or less, and even more preferably 75% by weight or less. (a) When the polypropylene resin is contained in an amount of 70% by weight or less, easy peel properties are maintained. (b) The content of the polyethylene resin in the resin composition is more preferably 12% by weight or more, even more preferably 15% by weight or more, and particularly preferably 20% by weight or more. If the polyethylene resin content is 10% by weight or more, the peel strength between the seal layers after heat sealing is likely to decrease. The content of (b) polyethylene resin in the resin composition is more preferably 35% by weight or less, even more preferably 30% by weight or less, and even more preferably 20% by weight or less. When the content of (b) polyethylene resin is about 40% by weight, heat resistance is less likely to decrease. (c) The content of silylated polyolefin resin in the resin composition is more preferably 5% by weight or more, even more preferably 7% by weight or more, and particularly preferably 12% by weight or more. When the content of silylated polyolefin resin is 3% by weight or more, sufficient liquid repellency is obtained, and liquid repellency against edible oils is particularly excellent. The content of (c) silylated polyolefin resin in the resin composition is more preferably 25% by weight or less, even more preferably 20% by weight or less, and even more preferably 15% by weight or less. A content of (c) silylated polyolefin resin of about 30% by weight does not significantly improve the liquid repellency. A lower content of (c) silylated polyolefin resin results in less segregation on the surface of the sealing layer. The contents of (a) polypropylene resin, (b) polyethylene resin, and (c) silylated polyolefin are determined by the method described in the Examples.
[0052] (particle) The resin composition constituting the sealing layer preferably contains particles, preferably particles made of an inorganic oxide or synthetic resin. The inclusion of particles facilitates achieving an arithmetic mean roughness Ra of the surface of the sealing layer of 0.03 μm or more and 0.3 μm or less. As a result, the coefficient of dynamic friction between the surfaces of the sealing layers of the film or between the sealing layer and its opposite surface, and the blocking strength of the lubricity between the surfaces of the sealing layers of the film, tend to be significantly reduced. The reason for this is thought to be that (c) the silylated polyolefin resin is unevenly distributed on the surface of the sealing layer, and by imparting specific irregularities to the film surface, which has reduced crystallinity and hardness, the impact of these decreases is reduced, and the dynamic friction coefficient and blocking strength are significantly reduced. The weight average particle size of the particles made of inorganic oxide or synthetic resin is preferably 2 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The weight average particle size is measured by the method described in the examples. Examples of particles made of synthetic resin include crosslinked acrylic particles, polymethacrylic acid particles, silicone resin particles, and polyethylene particles. Examples of inorganic oxide particles include silicon oxide particles, calcium carbonate particles, zeolite, and diatomaceous earth particles. Among silicon oxide particles, silica particles and synthetic silica particles are preferred, but diatomaceous earth may also be used in combination. The content of inorganic oxide or synthetic resin particles in the resin composition is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, and even more preferably 0.4 wt% or more. It is also preferably 3.0 wt% or less, more preferably 2.5 wt% or less, and even more preferably 2.0 wt% or less. When the content of inorganic oxide or synthetic resin particles is 3.0 wt% or less, the surface protrusions do not become too large, and the liquid repellency is not easily reduced.
[0053] (organic lubricant) The resin composition constituting the sealing layer preferably contains an organic lubricant, preferably a fatty acid amide, which has a synergistic effect of setting the arithmetic mean roughness Ra of the surface of the sealing layer to 0.03 μm or more and 0.3 μm or less, thereby easily improving the blocking resistance and slip properties of the sealing layer. Examples of fatty acid amides include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, etc. These may be used alone, but it is preferable to use two or more of them in combination, since this allows the lubricity and anti-blocking effects to be maintained even under harsh environments. On the other hand, fatty acid esters are widely known as emulsifiers and are also known to have the effect of imparting hydrophilicity to the film surface as anti-fogging agents, but in the present invention, they are not preferred because they not only reduce water repellency but also impair oil repellency. Furthermore, many fatty acid esters have low melting points, which raises concerns about stickiness and poor appearance due to bleed-out. Considering these points, fatty acid amides are preferred. It is preferable to add an organic lubricant with a melting point of 25°C or higher. The content of (d) fatty acid amide and fatty acid ester in the resin composition is preferably 0.01 to 0.5 wt%, more preferably 0.05 to 0.4 wt%, and particularly preferably 0.1 to 0.3 wt%. If the fatty acid amide is 0.5 wt% or less, the seal strength is unlikely to decrease.
[0054] (others) The resin composition may contain additives such as antioxidants, heat stabilizers, weather stabilizers, and crystal nucleating agents, as well as ethylene-vinyl acetate copolymers and ethylene-acrylate copolymers, as needed, within the range that does not impair the performance of the sealant film of the present invention.
[0055] (Film forming method) The method for producing the sealant film of the present invention preferably includes, for example, a step of melt-kneading a polypropylene-based resin composition containing a polyethylene-based resin, a step of melt-extruding the melt-kneaded resin composition to form a molten resin composition sheet, and a step of cooling and solidifying the molten resin composition sheet. The sealant film of the present invention may be a single layer, but is preferably a laminated film. In the laminated film, a layer containing a polyethylene resin and a silylated polyolefin and having an arithmetic mean roughness of 0.03 μm or more and 0.3 μm or less on at least one surface thereof may be provided with another layer made of a thermoplastic resin composition, preferably a polyolefin resin composition. In the case of a single layer, the film thickness is preferably 3 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and particularly preferably 20 μm or more. Also, the film thickness is preferably 200 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less. If the film thickness is less than 3 μm, the effect of the silica particles is reduced, and the effects of anti-slip and anti-locking properties are not easily achieved. The details are explained below: The longitudinal direction means the direction in which the unstretched sheet travels, and the width direction means the direction perpendicular to the longitudinal direction.
[0056] (raw material mixing process) When mixing a silylated polyolefin resin with a polyethylene-based resin, or particles such as silica particles with a polypropylene-based resin, any method may be used as long as they are mixed uniformly. When a masterbatch is used, examples of the method include mixing using a ribbon blender, a Henschel mixer, a tumbler mixer, etc.
[0057] (Melting and kneading process) First, the film raw material, such as polypropylene resin, is dried or hot-air dried so that the moisture content is less than 1000 ppm. Next, the raw materials are weighed, mixed, and fed into an extruder where they are melt-kneaded. The lower limit of the melt mixing temperature of the polyethylene resin composition is preferably 200°C, more preferably 210°C, and even more preferably 220°C. If the temperature is lower than this, discharge may become unstable. The upper limit of the resin melting temperature is preferably 260°C. If the temperature exceeds this limit, decomposition of the resin progresses, and the amount of cross-linked organic matter, so-called gel, and other foreign matter generated as a result of recombination increases. When the polyethylene resin composition contains the above-mentioned antioxidant, melt extrusion at a higher temperature becomes possible, but it is preferable to keep the temperature at 270°C or lower.
[0058] (filtration) In the melt-kneading process, high-precision filtration can be performed to remove foreign matter contained in the molten polyethylene resin composition.The filter material used for high-precision filtration of the molten resin is not particularly limited, but in the case of a filter material made of sintered stainless steel, it is excellent in removing foreign matter such as gel, as well as aggregates mainly composed of Al, Si, Ti, Sb, Cu, and Ge derived from additives such as catalysts.In addition, its filtration precision is preferably 200 μm or less.
[0059] (filter boost) The amount of pressure increase during melt-kneading of the polyethylene resin composition is preferably small.
[0060] (Melt extrusion process) Next, the molten polypropylene resin composition sheet is melt-extruded, for example, through a T-die, cast onto a chill roll, and cooled and solidified to obtain an unstretched sheet. A specific method for this is preferably casting onto a chill roll. The silylated polyolefin used in the present invention is a copolymer with polyethylene, so no bleeding out is observed even after undergoing melt-kneading and extrusion processes, and the accumulation of foreign matter and gunk that occurs when silicone resins are added is extremely unlikely to occur. Examples of methods include melt-extruding a melt-kneaded polypropylene resin composition sheet and forming it into a film using the T-die method or inflation method, but the T-die method is particularly desirable because it allows the melting temperature of the resin to be increased.
[0061] (Lip stains (bleed-out)) When silylated polyolefin, silica particles, and a polypropylene resin are melt-extruded through a T-die, it is preferable that the lip opening of the T-die is less soiled. The lip soiling was measured by the method described in the Examples.
[0062] (Cooling solidification process) For example, it is preferable to cast a molten sheet of the polyethylene resin composition melt-extruded from a T-die onto a cooling roll and then cool it. The lower limit of the cooling roll temperature is preferably 10°C. If the temperature is lower than this, not only may the crystallization suppression effect become saturated, but problems such as condensation may also occur, which is not preferable. The upper limit of the cooling roll temperature is preferably 70°C or lower. If the temperature exceeds this range, crystallization will proceed and transparency will deteriorate, which is not preferable. Furthermore, when the cooling roll temperature is within the above range, it is preferable to reduce the humidity of the environment around the cooling roll to prevent condensation. During casting, the surface of the chill roll rises in temperature because the hot resin comes into contact with the surface. Typically, chill rolls are cooled by running cooling water through piping inside. However, it is necessary to minimize the temperature difference across the width of the chill roll surface by ensuring a sufficient amount of cooling water, devising an appropriate piping layout, 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 to 200 μm.
[0063] (Multi-layer configuration) The sealant film of the present invention preferably has a multilayer structure. In the case of a multilayer structure, in addition to having a layer containing a polyolefin resin and a silylated polyolefin and having a surface layer with an arithmetic mean roughness of 0.03 μm or more and 0.3 μm or less on at least one side, one or more other layers made of a thermoplastic resin composition, preferably a polyolefin resin composition, may be provided. By using a multi-layer film and including a silylated polyolefin resin only in the surface layer, the amount of silylated polyolefin resin used can be reduced, and its precipitation can be minimized.Furthermore, other properties of the film can be improved and new functions can be imparted. As a specific method for forming the layers in this way, a general layering device (such as a multi-layer feed block, a static mixer, or a multi-layer multi-manifold) can be used. For example, a method can be used in which thermoplastic resins discharged from different passages using two or more extruders are laminated into multiple layers using a feed block, a static mixer, a multi-manifold die, etc. It is also possible to use only one extruder and introduce the above-mentioned layering device into the melt line from the extruder to the T-die.
[0064] In the case of a two-layer structure, it is preferable that at least one layer contains a polyolefin resin and a silylated polyolefin resin and has an arithmetic mean roughness of the surface layer of 0.03 μm or more and 0.3 μm or less, and be the sealing layer (layer A), and the other layer made of a thermoplastic resin composition, preferably a polyolefin resin composition, be the laminate layer (layer C).
[0065] In the case of a three-layer structure, it is preferable that at least one layer contains a polyolefin resin and a silylated polyolefin resin, and the layer having an arithmetic mean roughness of the surface layer of 0.03 μm or more and 0.3 μm or less is designated as a sealing layer (layer A), and other layers made of a thermoplastic resin composition, preferably a polyolefin resin composition, are designated as an intermediate layer (layer B) and a laminate layer (layer C), in that order. The outermost layers are layer A and layer C, respectively.
[0066] The polyolefin resin used for the intermediate layer (layer B) and laminate layer (layer C) is preferably a polyethylene resin or a polypropylene resin.
[0067] (Polyethylene resin) The polyethylene resin used in the intermediate layer (B layer) and laminate layer (C layer) is any one of a homopolymer of an ethylene monomer, a copolymer of an ethylene monomer and an α-olefin, a copolymer of an ethylene monomer and another monomer, and a mixture thereof. Examples of the α-olefin include propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, decene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1. Examples of other monomers include vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters. The polyethylene resin may be a crystalline, low-crystalline or non-crystalline random or block copolymer, or a mixture thereof. Copolymers of ethylene monomer and α-olefins are generally also called high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene. The use of these polyethylene resins provides excellent heat seal strength, hot tack, impurity sealability, and impact resistance, but it is preferable that they contain a small amount of, or no, copolymers of ethylene monomers with other monomers. In this case, the polyethylene resins used in the intermediate layer (B layer) and the laminate layer (C layer) may be the same or different.
[0068] In this case, it is preferable that the average density of the polyethylene resin in each layer of the film is such that: sealant layer (layer A) ≦ intermediate layer (layer B) ≦ laminate layer (layer C). The organic lubricant contained therein does not easily migrate to layers with higher densities, and is therefore effective in maintaining the lubricity of the sealant layer after lamination. In this case, the lower limit of the density of the intermediate layer (B layer) is preferably 880 kg / m 3 and more preferably 890 kg / m 3 and more preferably 900 kg / m 3 is. If the thickness is less than the above, the strength may be weak and difficult to process. The upper limit of the density of the intermediate layer (B layer) is preferably 940 kg / m 3 and more preferably 930 kg / m 3 and more preferably 920 kg / m 3 is.
[0069] (Polypropylene resin) The polypropylene resin used in the intermediate layer (B layer) and laminate layer (C layer) is a homopolymer of a propylene monomer, a random copolymer and / or a block copolymer of a propylene monomer and an α-olefin, or a mixture thereof. Examples of the α-olefin include ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, octene-1, and decene-1.
[0070] The organic lubricant may be used in the intermediate layer (layer B) of the film of the present invention, and the lower limit of the organic lubricant is preferably 200 ppm, more preferably 400 ppm. If the amount is less than the above, the lubricating properties may deteriorate. The upper limit of the erucic acid amide concentration in the intermediate layer is preferably 2000 ppm, more preferably 1500 ppm. If the upper limit is exceeded, the film becomes too slippery and may become misaligned during winding.
[0071] The intermediate layer (layer B) of the film of the present invention may contain 10 to 30% by mass of recycled resin. In the present invention, it is preferable to subject the laminate layer (layer C) surface of the polyethylene sealant film exemplified above to actinic ray treatment such as corona treatment, which improves the laminate strength.
[0072] (Film characteristics) The properties of the sealant film of the present invention will now be described in detail. (Ratio of silicon atoms Si to carbon atoms C in the sealing layer (Si / C) (average Si concentration)) The ratio of silicon atoms Si to carbon atoms C (Si / C) in the seal layer of the sealant film of the present invention is preferably 0.001 or more. When the ratio is 0.001 or more, the liquid repellency against sticky contents such as edible oil, pork cutlet sauce, and soy sauce is improved. A ratio of 0.005 or more is more preferable, 0.007 or more is even more preferable, and 0.01 or more is particularly preferable. The ratio of silicon atoms Si to carbon atoms C (Si / C) in the seal layer of the sealant film of the present invention is preferably 0.02 or less. When it is 0.02 or less, the peel strength is less likely to decrease. It is more preferably 0.018 or less, and even more preferably 0.016 or less. The measurement is carried out by the method described in the Examples.
[0073] (Silicon atoms S on the surface of the sealing layer i and the abundance ratio of carbon atoms (S i / C)(Surface S i concentration)) The ratio of silicon atoms Si to carbon atoms C (S i / C) is preferably 0.05 or more. When it is 0.05 or more, the liquid repellency against viscous contents such as edible oil, pork cutlet sauce, and soy sauce is improved, and the effect of improving the liquid repellency against edible oil is particularly great. It is more preferably 0.07 or more, even more preferably 0.1 or more, preferably 0.13 or more, and particularly preferably 0.15 or more. Silicon atoms S on the surface of the sealing layer of the sealant film of the present invention i and the abundance ratio of carbon atoms (S i / C) is preferably 0.3 or less. If it is 0.3 or less, the heat seal strength tends to decrease. It is more preferably 0.2 or less. The measurement is carried out by the method described in the Examples.
[0074] (Ratio of surface Si concentration to average Si concentration) Silicon atoms S contained in the sealing layer of the sealant film of the present invention i and the abundance ratio of carbon atoms (S i / C) silicon atoms S on the surface of the sealing layer i and the abundance ratio of carbon atoms (S i / C) is preferably 2 or more, more preferably 3 or more, even more preferably 5 or more, even more preferably 6 or more, particularly preferably 8 or more, and most preferably 10 or more. The measurement is carried out by the method described in the Examples. (arithmetic mean roughness Ra) The arithmetic mean roughness Ra of the surface of the sealing layer of the sealant film of the present invention is preferably 0.03 μm or more. A roughness of 0.03 μm or more reduces the coefficient of dynamic friction between the layers or between the layer and the film surface opposite the layer, which tends to reduce the coefficient of dynamic friction between the surfaces of the sealing layers of the film or between the sealing layer and the surface opposite the layer. It also tends to reduce the blocking strength of the lubricity between the surfaces of the sealing layers of the film. As a result, the film is easier to handle. The arithmetic mean roughness of the surface of the sealing layer is more preferably 0.05 μm or more, and even more preferably 0.07 μm or more. The arithmetic mean roughness Ra of the surface of the seal layer of the sealant film of the present invention is preferably 0.3 μm or less. If it is 0.3 μm or less, the coefficient of dynamic friction between the layers or between the layer and the film surface opposite the layer is not too small, making the film less likely to slip when wound and improving the handling of the film. It is more preferably 0.25 or less. The measurement is carried out by the method described in the Examples.
[0075] (Maximum protrusion height Rz) The maximum protrusion height Rz on the surface of the sealing layer of the sealant film of the present invention is preferably 1 μm or more. When the maximum protrusion height Rz is 1 μm or more, the contact area between the layers or between the layer and the film surface opposite the layer is reduced, significantly improving the anti-blocking effect and improving the handleability of the film. The maximum protrusion height Rz on the surface of the sealing layer is more preferably 1 μm or more, and even more preferably 3 μm or more. The maximum protrusion height Rz on the surface of the sealing layer of the sealant film of the present invention is preferably 30 μm or less. If it is 30 μm or less, the volume of the gap between the layers or between the layer and the film surface on the opposite side of the layer is not too large, making the film less susceptible to slippage during winding and improving the handling of the film. It is more preferably 25 μm or less. The measurement is carried out by the method described in the Examples.
[0076] (Young's modulus / longitudinal direction) The lower limit of the Young's modulus (longitudinal direction) of the sealant film of the present invention is preferably 100 MPa, more preferably 150 MPa, still more preferably 200 MPa, and particularly preferably 250 MPa. If it is 100 MPa or more, the film is not too weak and is easy to process. The upper limit of the Young's modulus (longitudinal direction) of the sealant film of the present invention is preferably 600 MPa, more preferably 500 MPa, and even more preferably 400 MPa.
[0077] (Young's modulus / width direction) The lower limit of the Young's modulus (width direction) of the sealant film of the present invention is preferably 100 MPa, more preferably 150 MPa, still more preferably 200 MPa, and particularly preferably 250 MPa. If it is 100 MPa or more, the film is not too weak and is easy to process. The upper limit of the Young's modulus (width direction) of the sealant film of the present invention is preferably 600 MPa, more preferably 500 MPa, and even more preferably 400 MPa.
[0078] (Hayes) The upper limit of the haze of the sealant film of the present invention is preferably 15%, more preferably 10%, and even more preferably 6%. If it is 15% or less, the contents can be easily seen. The lower limit of the haze of the sealant film of the present invention is preferably 0%, but even 2% is practically satisfactory. The measurement is carried out by the method described in the Examples.
[0079] (liquid repellency) The remaining amount of sticky contents such as edible oil, pork cutlet sauce, and soy sauce, which is an index for evaluating the liquid repellency of the sealant film of the present invention, is 0.08 mg / 28 cm for at least two of these. 2 It is preferable that the concentration is less than 0.8 mg / 28 cm for the three types. 2 More preferably, it is: The measurement is carried out by the method described in the Examples.
[0080] (Silylated Polyolefin Resin State) The seal layer of the sealant film of the present invention preferably has the silylated polyolefin resin segregated on the surface, but it is preferable that the silylated polyolefin resin does not accumulate in a separated state on the surface of the seal layer. In this case, it is preferable that the silylated polyolefin resin is finely dispersed in the seal layer of the sealant film of the present invention, and that the film exhibits a microphase-separated structure. The state of the silylated polyolefin resin or silicone resin on the surface of the sealing layer can be observed using a scanning electron microscope, and qualitative analysis of the Si and C elements can also be performed using energy dispersive X-rays. The cross section of the sealing layer can also be observed using a transmission electron microscope. The measurement is carried out by the method described in the Examples.
[0081] (dynamic friction coefficient) The upper limit of the dynamic friction coefficient between the seal layers of the sealant film of the present invention is preferably 1.5, more preferably 1.0, even more preferably 0.7, even more preferably 0.5, particularly preferably 0.4, and most preferably 0.3. When the dynamic friction coefficient between the seal layers is 1.5 or less, the opening properties after bag formation are good and loss during processing is likely to be reduced. The lower limit of the dynamic friction coefficient between the seal layers of the sealant film of the present invention is preferably 0.05, more preferably 0.08, and more preferably 0.1. When it is 0.05 or more, heat sealing during bag formation is easy and loss during processing is likely to be reduced. The upper limit of the dynamic friction coefficient between the sealing layer and the opposite surface of the film in the sealant film of the present invention is preferably 2.0, more preferably 1.5, even more preferably 1.2, still more preferably 1.0, particularly preferably 0.7, and most preferably 0.5. When the dynamic friction coefficient between the sealing layer and the opposite surface of the film is 2.0 or less, the film is less likely to wrinkle during winding, and loss during processing is likely to be reduced. The lower limit of the dynamic friction coefficient between the sealing layer and the opposite surface of the film of the sealant film of the present invention is preferably 0.05, more preferably 0.08, and even more preferably 0.1. When the coefficient is 0.05 or more, the film does not slip too much during winding, and is less likely to slip during winding. The measurement is carried out by the method described in the Examples.
[0082] (coefficient of static friction) The upper limit of the coefficient of static friction between the seal layers of the sealant film of the present invention is preferably 1.5, more preferably 1.0, even more preferably 0.7, still more preferably 0.5, particularly preferably 0.4, and most preferably 0.3. When the coefficient of dynamic friction between the seal layers is 1.5 or less, the opening property after bag formation is good, and loss during processing is likely to be reduced. The lower limit of the static friction coefficient between the sealing layers of the sealant film of the present invention is preferably 0.05, more preferably 0.08, and even more preferably 0.1. When the coefficient is 0.05 or more, heat sealing during bag production is easy to perform, and loss during processing is likely to be reduced. The measurement is carried out by the method described in the Examples.
[0083] (Blocking value) The upper limit of the blocking value of the lubricity between the surfaces of the seal layer of the sealant film of the present invention is preferably 100 mN / 70 mm, more preferably 90 mN / 70 mm, even more preferably 80 mN / 70 mm, particularly preferably 70 mN / 70 mm, and most preferably 60 mN / 20 mm. When the blocking strength of the lubricity between the surfaces of the seal layer is 100 mN / 70 mm or less, the film can be smoothly unwound from the film roll for processing. The lower limit of the blocking strength of the surface-to-surface lubrication of the sealing layer of the sealant film of the present invention is preferably 0 mN / 70 mm, but even 15 mN / 70 mm is practically satisfactory. The measurement is carried out by the method described in the Examples.
[0084] (150℃ easy peel strength) The 150° C. easy peel strength of the sealant film of the present invention is preferably 25 mN / 15 mm or less, more preferably 20 mN / 15 mm or less, and even more preferably 15 mN / 10 mm or less. The measurement is carried out by the method described in the Examples.
[0085] (190℃ easy peel strength) The 190° C. easy peel strength of the sealant film of the present invention is preferably 30 mN / 15 mm or less, more preferably 25 mN / 15 mm or less, and even more preferably 20 mN / 15 mm or less. The measurement is carried out by the method described in the Examples.
[0086] (200℃ easy peel strength) The 200° C. easy peel strength of the sealant film of the present invention is preferably 35 mN / 15 mm or less, more preferably 30 mN / 15 mm or less, and even more preferably 25 mN / 20 mm or less. The measurement is carried out by the method described in the Examples.
[0087] (150℃ peel strength) The 150°C peel strength of the sealant film of the present invention is preferably 0.5 N / 15 mm or more, more preferably 0.7 N / 15 mm or more, and even more preferably 0.9 N / 15 mm or more. The measurement is carried out by the method described in the Examples.
[0088] (190℃ peel strength) The 190°C peel strength of the sealant film of the present invention is preferably 1 N / 15 mm or more, more preferably 1.5 N / 15 mm or more, and even more preferably 1.8 N / 15 mm or more. The measurement is carried out by the method described in the Examples.
[0089] (200℃ peel strength) The 200°C peel strength of the sealant film of the present invention is preferably 1 N / 15 mm or more, more preferably 1.5 N / 15 mm or more, and even more preferably 1.8 N / 15 mm or more. The measurement is carried out by the method described in the Examples.
[0090] (Laminate) The sealant film of the present invention is configured as a laminate with at least one other base film laminated thereon, and is generally used as a packaging film or packaging sheet. The substrate film is not particularly limited, and may be appropriately selected and used depending on the intended use of the laminate, including polyolefin films such as polyethylene and polypropylene, styrene resin films, polyester films such as polyethylene terephthalate and polybutylene terephthalate, polyamide films such as nylon 6 and nylon 6,6, or stretched films thereof, laminated films of polyolefin films and gas-barrier resin films such as polyamide films or ethylene-vinyl alcohol copolymer films, metal foils such as aluminum, or vapor-deposited films or paper on which aluminum, silica, etc. are vapor-deposited. These substrate films may be used singly or in combination of two or more.
[0091] The substrate film adjacent to the sealant layer preferably does not contain the silylated polyolefin, and the substrate film adjacent to the sealant layer is preferably a polyolefin film.
[0092] The method for laminating the sealant film onto the base film may include dry lamination of the base film (Y) and the sealant film, extrusion lamination in which only the sealant layer resin is extruded and laminated onto the base film, etc. Among these, dry lamination is preferred from the viewpoint of productivity.
[0093] In order to more firmly bond the sealant film of the present invention to another substrate film, the structure may be sealant film / adhesive layer / another substrate film. The adhesive layer may use an anchor coating agent such as a urethane-based or isocyanate-based adhesive, or a modified polyolefin such as an unsaturated carboxylic acid-grafted polyolefin as an adhesive resin, thereby firmly bonding adjacent layers.
[0094] There are no particular restrictions on the thickness of the laminate, but when the laminate is used as a film for a lid or the like, it is preferably 10 to 200 μm, and when it is used as a sheet for cups or trays, it is preferably 200 to 1000 μm.
[0095] (packaging) A container can be produced by placing the sealant films of the laminate face to face, or by placing the sealant film layer of the laminate face to another substrate film, and then heat-sealing at least a portion of the periphery from the outer surface side to form a desired container shape. Alternatively, a sealed bag-like container can be produced by heat-sealing the entire periphery. By combining this bag-like container forming process with a filling process, i.e., by heat-sealing the bottom and sides of the bag-like container, filling it with contents, and then heat-sealing the top, a package can be produced. Therefore, this laminate can be used in automatic packaging equipment for solid, powder, or liquid ingredients such as snack foods.
[0096] Alternatively, a container with the contents packaged therein can be obtained by filling a container formed into a cup shape by vacuum forming or pressure forming, a container obtained by injection molding or blow molding, or a container formed from a paper base material with the contents, and then covering it with the laminate of the present invention as a lid material and heat sealing it. [Example]
[0097] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. The measured values of the various items in the detailed description of the present invention and in the examples and comparative examples were measured by the following methods.
[0098] (Characteristics of raw materials) The density, melt flow rate (MFR), and melting point of the polyolefin resin and silylated polyolefin used to prepare the sealant film, as well as the weight average particle size and content ratio of particles made of inorganic oxide or synthetic resin, were measured using the following methods. These values can be obtained by checking the boundaries of all layers if the sealant film is a single layer, or by checking the boundaries of the relevant layers if the film is multilayered, using an electron microscope, scraping off only the relevant layer, dissolving only the target raw material in a solvent that is insoluble, filtering the solution, and then removing the solvent and measuring the residue in the same manner. Scraping off only the relevant layer from a multilayer film can be done relatively easily by laminating the sealant film onto a polyethylene terephthalate (PET) film or the like and then scraping it off with a razor or the like.
[0099] (Density:kg / cm 3 ) Measurement was carried out by the density gradient tube method according to JIS-K7112.
[0100] (Melt flow rate (MFR): g / 10 min) The measurements were made in accordance with JIS-K7210 at a temperature of 190°C for polyethylene resins and 230°C for polypropylene resins.
[0101] (Melting point: °C) Measurement was performed using a differential scanning calorimeter (DSC) manufactured by SII, with a sample weight of 10 mg and a heating rate of 10° C. / min. The detected melting endothermic peak temperature was taken as the melting point.
[0102] (Content of inorganic oxide or synthetic resin particles in the film: wt%) The content of particles made of inorganic oxide or synthetic resin in the film was calculated from the amount added in the raw material resin composition before processing. Even after film formation, it is possible to separate and measure the silica particles by dissolving the film in decane as a solvent at a temperature at which it completely dissolves, and then filtering the residue through a filter with a filtration accuracy of 2 μm. (weight average particle size of particles made of inorganic oxide or synthetic resin: μm) Particles made of inorganic oxides or synthetic resins can be calculated as the particle diameter that corresponds to a cumulative 50% by mass of the smallest particle size on a particle size distribution curve measured using, for example, a laser diffraction / scattering particle size distribution analyzer "MT3200II" manufactured by Nikkiso Co., Ltd.
[0103] The ease of precipitation of compounds from the resin composition constituting the seal layer of the obtained sealant film was measured by the following method. (Ease of precipitation of compounds from the resin composition constituting the seal layer) The resin composition used in the sealing layer of Comparative Example 1 was extruded as molten resin at 230°C from multiple 4 mm diameter nozzles arranged across the width of the extruder die, and the degree of compound accumulation (degree of contamination) around the nozzles was visually observed one hour after the start of extrusion, and the results were classified as either ○ or × using the standard (○) as follows. ○: No deposition of compounds around the nozzle was observed. ×: Deposition of compounds around the nozzle is clearly observed.
[0104] (Characteristics of sealant film) The properties of the resulting sealant films were measured by the following methods.
[0105] (Ratio of silicon atoms Si to carbon atoms C on the surface of the sealing layer) Before measurement, the surface of the sealing layer of the sealant film was wiped with ethanol. The surface of the sealing layer was excited using an X-ray electron spectrometer (ESCA) (K-Alpha, Thermo Fisher Scientific) with monochromatic ALKα radiation, an X-ray output of 12 kV, 6 mA, a photoelectron escape angle of 90°, a spot size of 400 μmφ, pass energy of 50 eV (narrow scan), and a step of 0.1 eV (narrow scan). The surface composition ratio of the detected elements was calculated. The obtained surface composition ratio of elements is for a depth region of about several nm to 10 nm from the film surface.
[0106] (Ratio of silicon atoms Si and carbon atoms C contained in the sealing layer (S i / C)(Average Si concentration)) 1) After roughly understanding the layer structure through cross-sectional observation, only the resin composition that constitutes the seal layer is scraped off with a feather blade. The scraped material is completely dissolved at 135°C in a mixed solvent of o-dichlorobenzene / deuterated benzene = 80 / 20 volume ratio. The sample concentration is about 25-30 mg / 0.7 mL. One-dimensional S i For the NMR measurements, approximately 1 wt% of acetylacetonate chromium (III) was added to the measurement solution. The following measurements were carried out on this sample to identify the chemical formula, molecular weight, and content of the silylated polyolefin resin contained in the resin composition constituting the sealing layer. 2) First, 1D NMR 1 H-NMR spectrum, 13 C-NMR spectrum, 13 C-DEPT spectrum, and 29 S i Using NMR spectra, the bonding of H, C, and Si elements was investigated while referring to Aldrich standard spectra and standard samples, and the general structure of the compound was identified. The measurement conditions are shown below. Equipment: Fourier transform nuclear magnetic resonance spectrometer (Bruker Japan, AVANCE NEO 600) Resonance frequency::1 H-NMR: 600.13 MHz, 13 C-NMR: 150.92 MHz, 29 S i -NMR: 119.22MHz Measurement temperature:: 1 H-NMR: 110 or 115 ° C. 13 C-NMR: 110 or 115 ° C. 13 C-DEPT: 110 or 115°C, 29 Si-NMR: 110℃ Pulse repetition time: 1 H-NMR: 3.75 seconds, 13 C-NMR: 2.8~2.9 seconds, 13 C-DEPT: 3.5 seconds, 29 S i -NMR:7.0 seconds Detected pulse angle: 1 H-NMR: 30°, 13 C-NMR: 30°, 29 S i -NMR: 90° 1 H-decoupling methods: 13 C-NMR: fully decoupled, 29 S i -NMR: Inverse gate decoupled (FID acquisition time 0.7 seconds) Accumulation count: :1 H-NMR: 16 times, 13 C-NMR: about 300 to 1200 times, 13 C-DEPT: Approximately 100 to 1100 times, 29 S i -NMR: Approximately 4000 times 3) Furthermore, two-dimensional NMR such as COSY and TOCSY 13 C-HSQC, HMBC, 29 S i -HMBC is used to 1 The correlation peak between H is connected to the neighboring H and the neighboring H. 1 Correlation peak between H, directly bonded 1 H, 13 C correlation peak, heteronuclear species separated by two or three bonds ( 1 H, 13C), the correlation peak of heteronuclear species separated by two or three bonds ( 1 H, 29 The correlation peaks of Si) were examined to identify in more detail the structural connections found by 1D NMR. 4) The ratio of silicon atoms present per carbon atom in the resin composition constituting the seal layer of the sealant film (S i / C) (average Si concentration) can be calculated from the molecular formula and molecular weight of the silylated polyolefin resin contained in the resin composition, and the content ratio in the resin composition that constitutes the sealing layer. As a specific example, the calculation method is given below when the resin composition constituting the seal layer is a mixture of a polymer consisting only of ethylene-derived structural units containing a vinyl group at the end of the main chain, a silylated polyolefin resin made from dimethylsiloxane as a raw material compound, and a polyethylene resin. The dimethylsiloxane concentration in the silylated polyolefin resin was calculated from the molecular formula of the silylated polyolefin resin. If this resin concentration is assumed to be 26% by weight, the average polydimethylsiloxane concentration in a composition in which 10 parts by weight of this silylated polyolefin is added to 90 parts by weight of polypropylene resin will be 2.6% by weight. The molecular formula for one unit of dimethylsiloxane is C2H6S i The molecular formula per polyolefin unit of silylated polyolefin resin is C2H4 (unit molecular weight 28.05), and the molecular formula per propylene unit of polypropylene resin is C3H6 (unit molecular weight 42.08). The amount of dimethylsiloxane per 1 kg of resin composition is (1000 × 2.6 / 100) / 74.15 = 0.35 mol, the amount of polyolefin in the silylated polyolefin resin is (1000 × (10-2.6) / 100) / 28.05 = 2.6 mol, and the amount of polypropylene resin is (1000 × 90 / 100) / 42.08 = 21.4 mol. Therefore, per 1 kg of resin composition, S i The amount of silicon (C) is 0.35 mol, and the amount of carbon (C) is 0.35 × 2 + 2.6 × 2 + 21.4 × 2 = 48.7 mol. The ratio of silicon atoms per carbon atom in the resin composition (S i / C) is calculated as 0.35 / 48.7 = 0.007.
[0107] (Arithmetic mean roughness Ra:μm) The arithmetic mean roughness Ra of an arbitrary 1 mm x 0.2 mm area on the surface of the sealing layer of a 3 cm x 3 cm square sealant film was measured using a contact surface roughness tester (Kosaka Laboratory, Model ET4000A) in accordance with JIS B0601-2001. Measurements were taken at three locations, and the average value was taken as the arithmetic mean roughness Ra.
[0108] (Maximum protrusion height Rz:μm) The maximum peak height Rz of any 1mm x 0.2mm area on the surface of the sealing layer of a 3cm x 3cm square sealant film was measured using a contact surface roughness tester (Kosaka Laboratory, Model ET4000A) in accordance with JIS B0601-2001. Measurements were taken at three locations, and the average value was taken as the maximum peak height Rz.
[0109] (Young's modulus, tensile breaking strength, tensile breaking elongation) The Young's modulus of the obtained sealant film in the longitudinal direction and width direction of the film was measured at 23°C in accordance with JIS K7127. A sample of 15 mm × 200 mm was cut out from the film and set in a tensile tester (Instron 5965, dual column tabletop tester, manufactured by Instron Japan Co., Ltd.) with a chuck width of 100 mm. A tensile test was carried out at a tensile speed of 200 mm / min. From the obtained strain-stress curve, Young's modulus was calculated from the slope of the linear portion at the beginning of elongation. The tensile breaking strength and tensile breaking elongation were the strength and elongation, respectively, at the time when the sample broke.
[0110] (Hayes) The obtained sealant film alone was measured for haze using a direct reading haze meter manufactured by Toyo Seiki Seisaku-sho, Ltd., in accordance with JIS-K-7105. Haze (%) = [Td (diffuse transmittance %) / Tt (total light transmittance %)] x 100
[0111] (liquid repellency) The liquid repellency of the resulting sealant film was evaluated as follows. (1) The sealant film was cut into a size of 10 cm in the longitudinal direction and 5 cm in the width direction, and double-sided tape (Nichiban Co., Ltd., NW-5, 5 mm wide) was attached to the surface of the laminate layer at the end of one longitudinal side and the end of one adjacent width direction. The film was then folded at the center of the width direction so that the sealing surface was facing out, and the double-sided tape was attached to the other surface of the laminate layer to create a 10 cm x 2.5 cm cylindrical strip. (2) The weight of the cylindrical strip prepared in (1) was measured. (3-1) The following evaluation liquids were poured into a 100 ml death cup so that each liquid accounted for approximately 70% of the volume. A weighed cylindrical strip was immersed in the evaluation liquid for 1 second, so that it was immersed up to a position 5.6 cm from the bottom. Inserting a metal ruler or similar support into the opening of the cylindrical strip during immersion facilitates handling and prevents the opening of the bag from being accidentally immersed in the evaluation liquid. Evaluation liquids: edible oil (product name: Nissin Salad Oil, manufactured by Nissin Oillio Group, Inc.), tonkatsu sauce (product name: Rich Sauce, manufactured by Kagome Co., Ltd.), soy sauce (name: Koikuchi Soy Sauce (Honjozo), manufactured by Kikkoman Foods Corporation). (3-2) With the evaluation liquid still attached to the cylindrical strip, the cylindrical strip was hung for 10 seconds with the longitudinal direction vertical, and then hung for 50 seconds with the longitudinal direction tilted at 45° to the horizontal while keeping the width direction horizontal. (4) The weight of the cylindrical strip with the evaluation liquid attached immediately after (3-2) was weighed, and the amount of remaining liquid was calculated from the difference between the weight and (2). The surface area of the cylindrical strip from the bottom to the position 5.6 cm was 28 cm. 2 is. Two or more of the three evaluation liquids were 0.08 / 8cm 2 If it exceeds 0.08 / 8cm, it is considered inferior. 2 The following cases are good, three types are 0.08 / 8cm 2 The following cases were rated as excellent ◎.
[0112] (Observation of the dispersion state of silylated polyolefin) The surface of the sealing layer of the obtained sealant film was observed using a scanning electron microscope and irradiated with energy dispersive X-rays to perform elemental qualitative analysis and mapping of the surface. The cross section was also observed using a transmission electron microscope. The observation method is described in detail below.
[0113] (Energy dispersive X-ray (EDX) elemental qualitative analysis) A sample (1 cm x 1 cm) was cut out of the obtained sealant film, placed on a sample stage with carbon tape attached, and coated with approximately 2 nm of platinum-palladium using a magnetron sputtering device to ensure conductivity, and then observed in high vacuum mode. Measurements were performed using a Hitachi S-3400N scanning electron microscope and a Bruker XFlash5010 energy dispersive X-ray detector, irradiating the samples with X-rays at an accelerating voltage of 8 kV. A qualitative analysis of elements was carried out from the X-ray spectrum of the entire observation field of the sealant film sample, and of the elements observed, carbon (C) was mapped in red and silicon (Si) in green.
[0114] (Transmission electron microscope (TEM) observation) Both sides of the resulting sealant film (1 cm x 1 cm) were subjected to osmium vapor deposition, and after treatment to prevent peeling from the epoxy resin, it was embedded in the epoxy resin. The embedded samples were cut perpendicular to the film surface in a frozen state using a cryomicrotome set at -130°C to obtain ultrathin sections. The cross section was stained in ruthenium tetroxide vapor for 30 minutes, then carbon deposition was performed, and the cross section was observed and photographed using a JEOL JEM2100 transmission electron microscope at an accelerating voltage of 200 kV.
[0115] (dynamic friction coefficient) The coefficient of dynamic friction between the film surfaces of the polyethylene resin sealant films was measured in accordance with JIS-K-7125, except for the conditions below. Environmental conditions: Measurement was performed after regulating humidity for 2 hours or more under 23°C and 50% RH. Measuring device: Toyo Baldwin TENSILON STM-T-50BP Measurement conditions: Size of fixed test piece: 297mm (longitudinal direction) x 105mm (lateral direction) Size of moving test piece: 70mm (longitudinal direction) x 50mm (lateral direction) Weight of the load: 0.5 kg Crosshead speed: 20mm / min Travel distance: 100mm or more Calculation method: Calculated using the average test force between 10mm and 50mm strokes and the mass of the load weight using the following formula. Friction coefficient = Average test force over a stroke of 10 mm to 40 mm / Mass of the load weight
[0116] (coefficient of static friction) The static friction coefficient was measured for each film surface of the polyethylene resin sealant film in accordance with JIS-P-8147, except for the conditions below. Environmental conditions: Measurement was performed after regulating humidity for 2 hours or more under 23°C and 50% RH. Measuring device: Friction measuring machine AN manufactured by Toyo Seiki Seisakusho Co., Ltd. Measurement conditions: Test piece size: 200mm (longitudinal) x 100mm (lateral) Size of the load weight: 100mm (longitudinal direction) x 60mm (lateral direction) Weight of the load: 1.0 kg Tilt speed: 1.5° / sec Measurement method: One test piece was fixed to an inclined plate, and the load weight with the other test piece attached was gently placed on it. The inclined plate was then tilted at a constant speed, and the tangent of the angle (tanθ) when the test piece with the weight attached began to slide was calculated, and this was taken as the static friction coefficient. The test was performed three times, and the average value was calculated.
[0117] (Blocking value) The test was performed under the following conditions: The blocking value was measured in accordance with D1893-67. The samples (10 cm in width, 15 cm in length) with the measurement surfaces overlapping each other were placed in a heat press (Tester Sangyo Co., Ltd., model: SA-303) so that the edge of a 7 cm x 7 cm aluminum plate (2 mm thick) was aligned at the center of the sample width (10 cm) and 1 cm inside the length direction (15 cm). The temperature was 50 °C and the pressure was 440 kgf / cm. 2 The mixture was subjected to pressure treatment for 15 minutes. The sample blocked by this pressure treatment and a bar (diameter 6 mm, material: aluminum) were attached to an autograph (Shimadzu Corporation, model: UA-3122), and the force required for the bar to peel off the blocked portion at a speed of 100 m / min was measured. In this case, it is assumed that the bar and the peeled surface are horizontal. Measurements were taken four times for each sample and the average value was displayed.
[0118] (Easy peel) The easy peel property was measured by the easy peel strength when sealed at 190°C, with a strength of 20mN / 15mm or less being rated as excellent ⊚, 30mN / 15mm or less being rated as good ◯, and over 30mN / 15mm being rated as poor x.
[0119] (Easy peel strength: mN / 15mm) A dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to the corona surface of a nylon film (biaxially oriented nylon film manufactured by Toyobo: N1100, 15 μm) at a solid content of 3 g / m 2 The solvent was evaporated in an oven at 80°C, and then the corona surface of the sealant film and the adhesive-coated surface of the nylon film were nipped and laminated between temperature-controlled rolls at 60°C. The laminated film was aged at 40°C for 2 days, and then the laminated film was collected. The sealant surface of the collected laminated film was overlapped with 300 μm of unstretched CPP sheet (WF577PG x 100%), and heat-sealed with a seal width of 15 mm, a seal pressure of 0.2 MPa, a seal time of 1.0 second, and seal temperatures of 150, 190°C, and 200°C. The laminate obtained by heat sealing was cut parallel to the longitudinal direction to a width of 15 mm to obtain a test piece. The test pieces were placed in an autograph (Shimadzu Corporation, Model: UA-3122) and the seal surface was peeled at a speed of 200 mm / min, and the maximum peel strength was measured. Three test pieces were measured at each sealing temperature, and the average value was used as the easy peel strength at each sealing temperature.
[0120] (Peel strength: mN / 15mm) A dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to the corona surface of a nylon film (biaxially oriented nylon film manufactured by Toyobo: N1100, 15 μm) at a solid content of 3 g / m 2 The solvent was evaporated in an oven at 80°C, and then the corona surface of the sealant film and the adhesive-coated surface of the nylon film were nipped and laminated between temperature-controlled rolls at 60°C. The laminated film was aged at 40°C for 2 days, and then the laminated film was collected. The collected laminated films were heat-sealed with the longitudinal directions aligned and the sealant films facing each other, with a sealing width of 15 mm, sealing pressures of 0.2, 0.4, and 0.6 MPa, sealing time of 1.0 second, and sealing temperatures of 150, 190°C, and 200°C. The laminate obtained by heat sealing was cut parallel to the longitudinal direction to a width of 15 mm to obtain a test piece. The test pieces were placed in an autograph (Shimadzu Corporation, Model: UA-3122) and the seal surface was peeled at a speed of 200 mm / min, and the maximum peel strength was measured. Three test pieces were measured at each sealing temperature, and the average value was used as the peel strength at each sealing temperature.
[0121] The following raw materials were used in the examples and comparative examples. (Polypropylene resin) (1) WF577PG (ethylene copolymer polypropylene, manufactured by Sumitomo Chemical Co., Ltd., MFR 3.2 g / 10 min, melting point 142 ° C) (2) EP3721 (propylene-ethylene block copolymer, manufactured by Sumitomo Chemical Co., Ltd., MFR 2.5 g / 10 min, melting point 143°C) (2) (Polyethylene resin) (1) F222 (low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 922 kg / m 3 , MFR 2.0g / 10min, melting point 110℃) (2) FV407 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 930 kg / m 3 , MFR 3.2g / 10min, melting point 124℃) (3) A-4070S (ethylene-α-olefin copolymer, manufactured by Mitsui Chemicals, Inc., density 870 kg / m 3 , MFR 3.6g / 10min, melting point 55℃) (4) A-1085S (ethylene-α-olefin copolymer, manufactured by Mitsui Chemicals, Inc., density 885 kg / m 3 , MFR 1.2g / 10min, melting point 66℃) (5) RS1405 (ethylene-α-olefin copolymer mixture, manufactured by Mitsui Chemicals, Inc.) (6) P0480 (ethylene-α-olefin copolymer, manufactured by Mitsui Chemicals, Inc., MFR 1.8 g / 10 min)
[0122] (Silylated polyolefin resin) (1) Exfora PP2000 (manufactured by Mitsui Fine Chemicals, Inc., contains 30% by weight of silylated polyprefin (olefin-silicone copolymer), 70% by weight of polypropylene, and has a density of 917 kg / m 3 , MFR 20g / 10min, melting point 125℃ and 160℃) (2) Exfora PE3027 (manufactured by Mitsui Chemicals Fine Co., Ltd., contains 30% by weight of silylated polyprefin (olefin-silicone copolymer), 70% by weight of low-density polyethylene, density 932kg / m 3 , MFR 30g / 10min, melting points 114℃ and 122℃) (3) EXFORA LL1513 (manufactured by Mitsui Chemicals Fine Co., Ltd., containing 30% by weight of silylated polypreffin (olefin-silicone copolymer) and 70% by weight of metallocene-based linear low-density polyethylene, with a density of 921 kg / m 3 , MFR 15g / 10min, melting points 102℃ and 121℃)
[0123] (particles made of inorganic oxides) Mixed pellets (MB) with (1) / (2) / (3) = 90 / 6 / 4 (weight%) (1) WF577PG (ethylene copolymer polypropylene) (2) KMP-130-10 (spherical silica particles, manufactured by Shin-Etsu Silicone Co., Ltd., weight average particle size 10 μm) (3) KMP-130-4 (spherical silica particles, manufactured by Shin-Etsu Silicone Co., Ltd., weight average particle size 10 μm)
[0124] (organic lubricant) (1) MS07 (containing 5% by weight of erucic acid amide, manufactured by Sumitomo Chemical Co., Ltd.)
[0125] Examples 1 to 12 Polypropylene resin, polyethylene resin, silylated polyolefin, spherical silica, diatomaceous earth, ethylene bisoleic acid amide, and erucic acid amide were mixed and melted in a twin-screw extruder to obtain the content ratios (wt%) shown in Table 1 to form a sealing layer.
[0126] Further, polypropylene resin and erucic acid amide were mixed and melted in a twin-screw extruder so as to have the content ratio (wt %) shown in Table 1, to form an intermediate layer.
[0127] Furthermore, as shown in Table 1, polypropylene resin was melted in a twin-screw extruder to form a laminate layer.
[0128] Using a multilayer film molding device, the molten resin composition of the sealant layer, the resin composition of the intermediate layer, and the resin composition of the laminate layer were laminated, and a single multilayer molten sheet was co-extruded through a T-die. The sheet was then brought into contact with a cooling roll to cool and solidify, yielding an unstretched sheet. The laminate surface of the obtained sheet was subjected to a corona discharge treatment, and then wound into a roll at a speed of 20 m / min to obtain a sealant film with a thickness of 60 μm and a wet tension of the laminate surface of 45 N / m. The detailed conditions are as follows: Sealant layer extruder diameter: 60mm Diameter of middle layer extruder: 90mm Diameter of laminating layer extruder: 45mm Mixing melting temperature of raw materials for sealant layer, intermediate layer, and laminate layer: 250℃ T-die width: 1600mm Multilayer molten sheet take-up speed: 20m / min Cooling roll temperature: 40℃ Thickness of the sealant layer in the sealant film: 6 μm Thickness of the middle layer in the sealant film: 42 μm Thickness of the laminate layer in the sealant film: 12 μm The longitudinal direction refers to the direction in which the unstretched sheet is run, and the width direction refers to the direction perpendicular to that. The properties of the obtained film are shown in Table 2.
[0129] The sealant films obtained in Examples 1 to 13 were excellent in liquid repellency and heat sealability. They also had excellent easy peel properties. Furthermore, the resin composition used in the sealing layer exhibited little compound precipitation and excellent film-forming processability. The reason for this is that the silylated polyolefin used in the sealing layer contains a dimethylsiloxane component, which has a low surface energy and therefore segregates on the surface of the sealing layer. FIG. 1 shows the average Si concentration and surface Si concentration of the films described in Comparative Examples 1 and 4, and Examples 2 to 4, and 13. The Si concentration at the surface of the sealing layer of the films described in Comparative Examples 1 and 4, and Examples 2 to 4, and 13 is up to approximately 46.5 times higher than the average Si concentration in the entire sealing layer, indicating that silylated polyolefin segregates on the surface.
[0130] Figure 3 shows analytical images of silicon mapping on the surfaces of the sealing layers of Example 2 and Comparative Example 1. Silicon (green) is present over the entire surface in Example 2, but is not visible in Comparative Example 1. Silica particles are highlighted because they are primarily composed of silicon. Figure 4 shows TEM images of the cross sections of the sealing layers of Example 2 and Comparative Example 7. The silylated polyolefin of Example 2 is a copolymer of dimethylsiloxane and polyethylene, and therefore, since the dimethylsiloxane is difficult to separate from the polyethylene, it exhibits a microphase-separated structure, but it is only finely dispersed. On the other hand, Comparative Example 7 contains a silicone resin, which is thought to have undergone phase separation or precipitation. Figure 5 is a photograph of the die nozzle surrounding the seal layer raw materials of Example 2 and Comparative Example 7, which were melt-kneaded in a twin-screw extruder. No compound deposition was observed in Example 2, suggesting that the silylated polyolefin in the seal layer would not precipitate on its surface. On the other hand, precipitation of silicone resin was observed in Comparative Example 7, raising concerns about the presence of foreign matter in the film and a worsening of the working environment.
[0131] (Comparative Examples 1 to 7) A sealant film was obtained in the same manner as in Example 1, except that the compounds shown in Table 1 were used as raw materials for the resin compositions of the sealing layer, laminate layer, and intermediate layer.
[0132] The sealant film obtained in Comparative Example 1 was poor in liquid repellency and easy peelability.
[0133] The sealant film obtained in Comparative Example 2 was excellent in liquid repellency but had poor easy peel properties.
[0134] The sealant film obtained in Comparative Example 3 was poor in liquid repellency.
[0135] The sealant film obtained in Comparative Example 4 was excellent in liquid properties but had poor easy peel properties.
[0136] The sealant film obtained in Comparative Example 5 was excellent in liquid repellency but had poor easy peel properties.
[0137] The sealant film obtained in Comparative Example 6 was excellent in liquid repellency but had poor easy peel properties. Although the film had excellent liquid repellency and low blocking value and friction coefficient, the compound was prone to precipitate from the sealing layer, making it inferior as a sealant film.
[0138] The sealant film obtained in Comparative Example 7 was excellent in liquid properties but had poor easy peel properties. Although the film had excellent liquid repellency and low blocking value and friction coefficient, the compound was prone to precipitate from the sealing layer, making it inferior as a sealant film.
[0139] [Table 1]
[0140] [Table 2] [Industrial Applicability]
[0141] The sealant film of the present invention can easily remove even sticky contents such as pastes and viscous substances, and can provide a sealant film and laminate thereof that have good heat sealing properties and excellent easy peel properties, making a significant contribution to the industry.
Claims
1. A film for sealant comprising a sealing layer made of a resin composition containing the following (a), (b), and (c), and satisfying the following (1), (2), (3), (7), and (8): (a) Polypropylene resin (b) Polyethylene resin (c) Silylated polyethylene resin (1) The contents of (a), (b), and (c) are 30 to 70% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, based on the total weight of the resin composition. (2) Silylated polyethylene resin is represented by the following formula: CH 3 -(CH 2 ) n-2 -CH 2 -S i (CH 3 ) 2 O-(-S i (CH 3 ) 2 -O-) d -S i (CH 3 ) 2 -CH 2 -(CH 2 ) n-2 -CH 3 (In the formula, d is an integer of 1 or more, and n is an integer of 100 or more.) (3) The polyethylene resin is a high-pressure low-density polyethylene. (7) The resin composition contains particles made of an inorganic oxide or a synthetic resin. (8) The blocking value of the surface of the sealing layer is 200 mN / 70 mm or less.
2. A film for sealant comprising a sealing layer made of a resin composition containing the following (a), (b), and (c), and satisfying the following (1), (2), (3), (7), and (8): (a) Polypropylene resin (b) Polyethylene resin (c) Silylated polyethylene resin (1) The contents of (a), (b), and (c) are 30 to 70% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, based on the total weight of the resin composition. (2) Silylated polyethylene resin is represented by the following formula: CH 3 -(CH 2 ) n-2 -CH 2 -S i (CH 3 ) 2 O-(-S i (CH 3 ) 2 -O-) d -S i (CH 3 ) 2 -CH 2 -(CH 2 ) n-2 -CH 3 (In the formula, d is an integer of 1 or more, and n is an integer of 100 or more.) (3) The polyethylene resin is a linear low-density polyethylene. (7) The resin composition contains particles made of an inorganic oxide or a synthetic resin. (8) The blocking value of the surface of the sealing layer is 200 mN / 70 mm or less.
3. A film for sealant comprising a sealing layer made of a resin composition containing the following (a), (b), and (c), and satisfying the following (4), (5), (6), (7), and (8): (a) Polypropylene resin (b) Polyethylene resin (c) Silylated polyethylene resin (4) The contents of (a), (b), and (c) are 30 to 85% by weight, 10 to 40% by weight, and 3 to 30% by weight, respectively, based on the total weight of the resin composition. (5) Silylated polyethylene resin is represented by the following formula: CH 3 -(CH) 2 ) n-2 -CH 2 -S i (CH) 3 ) 2 O-(-Si(CH) 3 ) 2 -O-) d -Si(CH3) 2 -CH 2 -(CH) 2 ) n-2 -CH 3 (In the formula, d is an integer of 1 or more, and n is an integer of 100 or more.) (6) The polyethylene resin is an elastomer made of a copolymer of an ethylene monomer and an α-olefin. (7) The resin composition contains particles made of an inorganic oxide or a synthetic resin. (8) The blocking value of the surface of the sealing layer is 200 mN / 70 mm or less.
4. The sealant film according to any one of claims 1 to 3, wherein the resin composition contains a fatty acid amide.
5. A laminate comprising the sealant film according to any one of claims 1 to 3 and a substrate film.
6. A container comprising the laminate according to claim 5.
Citation Information
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