Multilayer film

Abstract

To provide a laminate film having mechanical characteristics necessary to use as a film and excellent adhesion to fabrics, handleability, and touching feel by improving defects of the prior art.SOLUTION: A laminate film has different peel strengths on both sides with respect to fabrics, wherein the laminate film is characterized by that, when the outermost layer on a side having relatively large peel strength with respect to fabrics is defined as A layer, a surface of the A layer includes a resin and particles, the maximum roughness (Rz) which is a surface roughness of the A layer is 80 μm or over and 200 μm or under, and the skewness (Rsk) is 1.00 or over and 4.00 or under.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a laminated film having excellent adhesion and touch feeling to materials having irregularities on the surface such as cloth and non-woven fabric.

Background Art

[0002] In recent years, there has been a demand for a single film that has mechanical properties necessary for use as a film and further has another function. For example, in the field of medical and hygienic materials, a film having mechanical properties as a film and excellent adhesion and touch feeling to materials such as cloth and non-woven fabric (hereinafter sometimes referred to as cloth etc.) having an uneven shape, stretchability, and flexibility on the surface is desired.

[0003] So far, various developments have been made to improve these properties. For example, Patent Document 1 discloses a film in which a filler having a particle size larger than the layer thickness is dispersed and contained in an adhesive resin layer. By adopting such a mode, adhesion to a roll or the like in a production line or the like can be reduced, and the handleability of the film is improved. Further, Patent Document 2 discloses a film having a surface formed of particles and an adhesive resin. By adopting such a mode, when touching the surface, the contact between the adhesive layer and the skin is suppressed by the particles, so that the touch feeling of the film is improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology of Patent Document 1, although it is possible to achieve both adhesion to cloth and handling properties, there is a problem that the outermost surface becomes an adhesive layer and the tactile sensation deteriorates. Further, in the technology of Patent Document 2, there is a problem that the tactile sensation deteriorates due to the particles on the surface falling off or being buried.

[0006] An object of the present invention is to improve the drawbacks of such conventional technologies, provide a laminated film having mechanical properties necessary for use as a film, and excellent in adhesion and tactile sensation to cloth and the like.

Means for Solving the Problems

[0007] To solve the above problems, the present invention has the following configuration. (1) A laminated film having different peel strengths with respect to cloth on both sides. When the outermost layer on the side with a relatively large peel strength with respect to cloth is defined as the A layer, the surface of the A layer contains a resin and particles, the maximum roughness (Rz) of the surface roughness of the A layer is 80 μm or more and 200 μm or less, and the skewness (Rsk) is 1.00 or more and 4.00 or less. A laminated film characterized by the above. (2) The laminated film according to (1), wherein the average particle diameter of the particles contained in the A layer is 10 μm or more and 100 μm or less. (3) The laminated film according to (1) or (2), wherein the amount of the particles contained in the A layer is 10% by mass or more and 55% by mass or less. (4) The laminated film according to any one of (1) to (3), wherein the maximum value of the Young's modulus is 50 MPa or more and 2000 MPa or less. (5) The laminated film according to any one of (1) to (4), wherein when a rosin resin, a terpene resin, and a petroleum resin are used as the adhesive resin, the A layer contains at least one kind of adhesive resin. (6) The laminated film according to any one of (1) to (5), wherein when the outermost layer on the side opposite to the A layer is defined as the B layer, the A layer contains more of the adhesive resin than the B layer.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a laminated film having mechanical properties necessary for use as a film and excellent in adhesion to cloth or the like and touch feeling.

Brief Description of Drawings

[0009]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0010] The laminated film of the present invention is a laminated film having different peel strengths with respect to cloth on both sides. When the outermost layer on the side with a relatively large peel strength with respect to cloth is defined as the A layer, the surface of the A layer contains a resin and particles, the maximum roughness (Rz) which is the surface roughness of the A layer is 80 μm or more and 200 μm or less, and the skewness (Rsk) is 1.00 or more and 4.00 or less.

[0011] A film refers to a sheet-shaped molded body mainly composed of a thermoplastic resin, and a laminated film refers to a film having a plurality of layers with different compositions. Here, "mainly composed of a thermoplastic resin" means that the thermoplastic resin is contained in an amount of more than 50% by mass and 100% by mass or less of all the components constituting the film.

[0012] It is important that the laminated film of the present invention has different peel strengths with respect to cloth on both sides. "Having different peel strengths with respect to cloth on both sides" means that the difference between the peel strength with respect to cloth on the surface with a relatively large peel strength with respect to cloth and the peel strength with respect to cloth on the opposite surface is 0.05 N / cm or more. At this time, the outermost layer on the side with a relatively large peel strength with respect to cloth is defined as the A layer, and the outermost layer on the opposite side is defined as the B layer.

[0013] The peel strength against the cloth can be measured by the following procedure. First, a rectangular film sample of 10 mm × 100 mm is obtained, and the obtained film sample is placed on a white polyester cloth (hereinafter sometimes simply referred to as cloth) compliant with JIS L 0803:2011, and a laminating roller with a load of 1 kg is reciprocated once to bring the two into close contact. Then, the film sample is peeled off from the short side at a tensile speed of 300 mm / min, and the peel strength against the cloth is measured by the method specified in JIS Z 0237:2009.

[0014] The method of making the laminated film in a mode where "the peel strength against the cloth is different on both sides" is not particularly limited as long as the effects of the present invention are not impaired. For example, a method of making one arbitrarily selected outermost layer and the other outermost layer have different compositions from each other can be mentioned. More specifically, it is a method in which the content of the pressure-sensitive adhesive resin (described later) in one arbitrarily selected outermost layer is different from the content of the pressure-sensitive adhesive resin in the other outermost layer. In such a mode, usually, the surface on the outermost layer side with a large content of the pressure-sensitive adhesive resin becomes the "surface with a relatively large peel strength against the cloth", the outermost layer with a large content of the pressure-sensitive adhesive resin is the A layer, and the outermost layer on the opposite side is the B layer. At this time, by increasing the difference between the content of the pressure-sensitive adhesive resin in the A layer and the content of the pressure-sensitive adhesive resin in the B layer, the difference in the peel strength against the cloth on both sides can be increased.

[0015] Note that the content of the pressure-sensitive adhesive resin in the A layer means the content (% by mass) of the pressure-sensitive adhesive resin when the total constituent components of the A layer are 100% by mass, and the content of the pressure-sensitive adhesive resin in the B layer is interpreted in the same way. At this time, the B layer does not necessarily have to contain a pressure-sensitive adhesive resin. The pressure-sensitive adhesive resin can improve the adhesion to cloth or the like, but is inferior in terms of mechanical strength compared to the resin that can be used in the B layer described later. Therefore, by adopting such a mode, it is possible to easily achieve both the mechanical properties of the film and the adhesion to cloth or the like. At this time, another layer may exist between the A layer and the B layer as long as the effects of the present invention are not impaired.

[0016] It is important that the surface of the A layer of the laminated film of the present invention contains a resin and particles. The resin in the A layer preferably contains a thermoplastic elastomer and a tacky resin from the viewpoints of adhesion to cloth and productivity.

[0017] A thermoplastic elastomer has a hard segment phase and a soft segment phase, and thus has rubber elasticity at 25°C. On the other hand, in the temperature range of 100°C to 300°C, which is a general thermoplastic molding temperature range, fluidity appears in the hard segment phase, enabling the same molding process as general thermoplastic resins. It refers to a high molecular weight substance. As the thermoplastic elastomer that can be used in the A layer, for example, polyester-based elastomers, polyolefin-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, styrene-based elastomers, and polyacrylic-based elastomers can be used alone or in combination. Among them, from the viewpoint of adhesion of the obtained film to cloth and the like, it is preferable to use a styrene-based elastomer.

[0018] Examples of styrene-based elastomers include styrene-butadiene block copolymers, styrene-ethylene propylene block copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene butylene-styrene block copolymers, and styrene-ethylene propylene-styrene block copolymers.

[0019] Tacky resins are rosin-based resins, terpene-based resins, and petroleum-based resins. When such tacky resins are blended with polymer materials, they exhibit tackiness due to a plasticizing effect. Therefore, when the A layer contains more tacky resin than the B layer, the adhesion between the A layer and cloth and the like is improved. "The A layer contains more tacky resin than the B layer" means that the content (mass%) of the tacky resin in the A layer is greater than the content (mass%) of the tacky resin in the B layer.

[0020] The rosin-based resin refers to a resin mainly composed of rosin acids (such as abietic acid, palustric acid, isopimaric acid, etc.). The rosin-based resin that can be used in the film of the present invention can be obtained, for example, as a residue remaining after distilling terpene essential oil by collecting balsams such as pine resin, which is the sap of plants of the Pinaceae family. Specific examples of rosin-based resins include unmodified rosins such as gum rosin, wood rosin, and tall oil rosin, and modified rosins obtained by modifying these unmodified rosins by hydrogenation, disproportionation, polymerization, and other chemical modifications, etc.

[0021] The petroleum resin refers to a resin obtained by polymerizing a part of the by-product oil of naphtha cracking (such as highly unsaturated dienes, etc.) into a resinous form. Examples of petroleum resins that can be used in the film of the present invention include aliphatic petroleum resins, aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, and hydrogenated products thereof, etc.

[0022] The terpene resin refers to a polymer of terpene monomers, a copolymer of terpene monomers and other monomers, and derivatives thereof. Examples of terpene resins include α-pinene polymers, β-pinene polymers, and dipentene polymers, etc., as well as modified terpene resins such as terpene phenol resins, styrene-modified terpene resins, and hydrogenated terpene resins, etc.

[0023] The particles contained in the A layer are not particularly limited as long as the effects of the present invention are not impaired, and may be either inorganic particles or organic particles, or a combination of organic particles and inorganic particles, or a combination of multiple types of inorganic particles or multiple types of organic particles. Examples of inorganic particles include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium oxide, and titanium oxide, etc. Examples of organic particles that can be used in the laminated film of the present invention include polyethylene resin, polyolefin resin, acrylic resin, urethane resin, styrene resin, urea resin, phenol resin, and epoxy resin, etc.

[0024] The shape of the particles is not particularly limited as long as it does not impair the effects of the present invention, and may be any of spherical, lumpy, rod-like, flat, etc., and different shapes can be used in combination as necessary, but spherical is preferable in terms of the feel of the resulting laminated film.

[0025] The average particle size of the particles contained in the A layer is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 80 μm or less, and particularly preferably 40 μm or more and 60 μm or less. If the average particle size of the particles in the A layer is 10 μm or more, it is easy to form unevenness on the surface of the A layer, and it is easy to improve the tactile feel of the A layer surface. On the other hand, if the average particle size of the particles in the A layer is 100 μm or less, it is possible to reduce the particles from falling off from the A layer.

[0026] The average particle size of the particles in the A layer can be determined by the following procedure. First, the surface of the A layer is observed using a laser microscope at a magnification where 3 to 10 particles that form a convex shape with a height of 5 μm or more on the A layer surface and are not aggregated are captured on the screen, and an observation image is obtained. A square or rectangle is drawn so as to completely surround the non-aggregated particles in the A layer in the obtained observation image and have the smallest area, and the average value of the length of one side in the case of a square, and the average value of the lengths of the long and short sides in the case of a rectangle is taken as the particle size of the particles. The measurement was performed on all non-aggregated particles captured in the obtained observation image, and the average value excluding the maximum and minimum particle sizes was obtained. Furthermore, the same measurement was performed 9 times at different measurement locations, and the average value of the obtained 10 values ​​was taken as the average particle size (μm) of the particles in the A layer.

[0027] In the laminated film of the present invention, the amount of particles contained in the A layer is preferably 10% by mass or more and 55% by mass or less, more preferably 20% by mass or more and 45% by mass or less. If the amount of particles contained in the A layer is 10% by mass or more, unevenness can be easily formed on the surface of the A layer. On the other hand, if the amount of particles contained in the A layer is 55% by mass or less, the adhesion of the resulting laminated film to cloth or the like is improved. The "amount of particles contained in the A layer" refers to the amount of particles in the A layer when the total components constituting the A layer are 100% by mass.

[0028] The amount of particles in the A layer can be measured by the following procedure. First, cut the laminated film into 10 cm × 10 cm and measure its mass. Further, immerse the cut laminated film in toluene for 30 minutes or more and take it out, and measure the mass of the dried film. The difference in mass before and after toluene immersion is the mass of the A layer. Next, take out the particles in the toluene solution and measure the mass of the dried particles. The value of (particle mass) / (A layer mass) is taken as the amount of particles in the A layer. If the particles are components that dissolve in toluene, other organic solvents can be appropriately substituted as the organic solvent for immersing the laminated film.

[0029] The maximum roughness (Rz), which is the surface roughness of the A layer in the laminated film of the present invention, is 80 μm or more and 200 μm or less, and it is important that the skewness (Rsk) of the A layer is 1.00 or more and 4.00 or less. The Rz of the A layer is preferably 90 μm or more and 200 μm or less, more preferably 100 μm or more and 200 μm or less. If Rz is 80 μm or more, a film with excellent touch can be obtained. If Rz is 200 μm or less, the dropout of particles in the A layer can be reduced. The Rsk is preferably 1.20 or more and 4.00 or less, more preferably 1.70 or more and 4.00 or less. If Rsk is 1.00 or more, a film with excellent touch can be obtained. If Rsk is 4.00 or less, the dropout of particles in the A layer can be reduced.

[0030] The tactile sensation referred to here means the tactile sensation when touching the A layer side of the laminated film, which can be evaluated using the coefficient of friction of the A layer as an index. More specifically, the smaller the coefficient of friction of the A layer, the less sticky feeling when touched, which means that the tactile sensation is excellent. The coefficient of friction of the A layer can be measured with a known roughness / friction sensation tester (for example, KES-SESRU, manufactured by Kato Tech Co., Ltd.), and the measurement conditions when using the device are as shown in the examples.

[0031] Rz and Rsk on the surface of the A layer can be adjusted by the average particle size of the particles, the addition amount of the particles, and the coating amount of the composition for forming the A layer. Specifically, Rz and Rsk can be increased by increasing the average particle size of the particles, increasing the addition amount of the particles, or decreasing the coating amount of the composition for forming the A layer. Also, Rz and Rsk can be decreased by decreasing the average particle size of the particles, decreasing the addition amount of the particles, or increasing the coating amount of the composition for forming the A layer.

[0032] Rz and Rsk can be measured by the following procedure. First, the surface of the A layer is observed with a laser microscope at a magnification at which 3 or more and 10 or less non-agglomerated particles that form convex portions on the A layer surface are within the screen. Then, the surface roughness of the captured image is determined using the measurement function of the laser microscope. The surface roughness is calculated for Rz and Rsk using the calculation formula conforming to JIS B0601:2001 without a cut-off.

[0033] The A layer may contain components other than the above-mentioned components as long as the effects of the present invention are not impaired. Such components include, for example, lubricants, antioxidants, ultraviolet stabilizers, matting agents, antibacterial agents, deodorants, weathering agents, antioxidants, ion exchangers, coloring pigments, and dyes.

[0034] The B layer in the laminated film of the present invention is not particularly limited, but it is preferably mainly composed of a thermoplastic resin such as a polyester resin, a polyolefin resin, and a polystyrene resin. Here, the "main component" means a component contained in the layer in an amount of more than 50% by mass and 100% by mass or less when the total resin components constituting the layer are 100% by mass.

[0035] The polyester resin refers to a homopolyester or a copolyester which is a polycondensate of a dicarboxylic acid component skeleton and a diol component skeleton. Here, examples of the homopolyester include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene diphenylate, and the like. The copolyester refers to a polycondensate composed of at least two or more components selected from the components having a dicarboxylic acid skeleton and the components having a glycol skeleton described below.

[0036] Examples of the component having a dicarboxylic acid skeleton include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid, and their ester derivatives.

[0037] Examples of the component having a glycol skeleton include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, polyalkylene glycol, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, isosorbide, 1,4-cyclohexanedimethanol, spiroglycol, and the like.

[0038] The polyolefin resin refers to a homopolymer of olefins such as ethylene and propylene, or a copolymer containing a plurality of olefins. Examples of the homopolymer of olefins include polyethylene and polypropylene. Examples of the copolymer containing olefins include ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and ethylene-vinyl chloride copolymer.

[0039] The polystyrene resin refers to a homopolymer of styrene or a copolymer containing styrene. An example of the homopolymer of styrene is polystyrene. Examples of the copolymer containing styrene include acrylonitrile styrene and acrylonitrile butadiene styrene.

[0040] Examples of the homopolymer of olefins include polyethylene and polypropylene. Examples of the copolymer with a different polyolefin include ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and ethylene-vinyl chloride copolymer. Among them, from the viewpoint of easily setting the Young's modulus of the obtained film within a preferable range described later, the B layer in the film of the present invention preferably contains polyethylene as a main component. Also, within a range not impairing the effects of the present invention, a plurality of polyolefin resins and other resins may be combined and used.

[0041] The B layer may contain a filler as long as its effects are not impaired. The filler refers to a substance added to improve various properties, or an inert substance added for the purpose of increasing the volume, increasing the capacity, or reducing the cost of the product. The type of the filler is not particularly limited as long as the effects of the present invention are not impaired, and an inorganic filler and / or an organic filler can be used. Also, as long as the effects of the present invention are not impaired, the filler may be of one type or a mixture of multiple types. From the viewpoint of easily making the Young's modulus of the obtained film fall within a preferable range described later, the filler is preferably an inorganic filler, and it is more preferable to use at least one of metal carbonates such as calcium carbonate, barium carbonate, and magnesium carbonate, metal sulfates such as barium sulfate and calcium sulfate, metal oxides such as titanium oxide and zinc oxide, composite oxides such as silicon oxide (silica), aluminosilicate, mica, talc, kaolin, clay, and montmorillonite. From the viewpoints of versatility and cost, it is even more preferable to use calcium carbonate alone or in combination with other fillers.

[0042] The content of the filler in the B layer is not particularly limited as long as the effects of the present invention are not impaired. However, from the viewpoint of easily making the Young's modulus of the obtained film fall within a preferable range described later, when the total resin component of the B layer is 100 parts by mass, it is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 150 parts by mass or less. Also, the B layer may contain components other than the above-described components as long as the effects of the present invention are not impaired. Examples of such components include lubricants, antioxidants, ultraviolet stabilizers, matting agents, antibacterial agents, deodorants, weathering agents, antioxidants, ion exchangers, coloring pigments, and dyes.

[0043] In order for the laminated film of the present invention to maintain mechanical properties and ensure followability with respect to cloth or the like when adhered to cloth or the like, it is preferable that the maximum value of the Young's modulus is 50 MPa or more and 2000 MPa or less. By setting the maximum value of the Young's modulus of the laminated film to 50 MPa or more, mechanical properties as a film are ensured, improving handleability. On the other hand, by setting the maximum value of the Young's modulus of the laminated film to 2000 MPa or less, followability with respect to cloth or the like is improved. From the above viewpoints, a more preferable range of the maximum value of the Young's modulus is 50 MPa or more and 500 MPa.

[0044] As a method for adjusting the maximum value of the Young's modulus of the laminated film, there is no particular limitation as long as the effects of the present invention are not impaired, and examples include a method of changing the composition of the base material layer. More specifically, by using a resin with low flexibility in the components of the base material layer or increasing its ratio, the maximum value of the Young's modulus can be increased.

[0045] Regarding the method for measuring the maximum value of the Young's modulus of the laminated film, it will be described using FIG. 1, which is a schematic diagram showing the measurement direction of the Young's modulus. First, a rectangular measurement sample with a size of 100 mm (width direction) × 10 mm (longitudinal direction) is prepared from the laminated film 1, and the Young's modulus in the width direction (2-2' in FIG. 1) is measured in accordance with ASTM-D882:1990 under the conditions of a tensile strength of 200 mm / min, a temperature of 23°C, and a humidity of 65%RH. The same measurement is repeated 5 times, and the average value of the obtained values is taken as the Young's modulus in the width direction. Subsequently, the sample is cut out in the same manner so that the direction rotated clockwise by 15° within the film plane from the width direction (3-3' in FIG. 1) becomes the measurement direction, and the measurement is performed in the same manner. Thereafter, as shown in FIG. 1, the measurement direction is shifted by 15° clockwise (4-4' → 8-8' (longitudinal direction)), and the Young's modulus is measured in the same manner. The values of the Young's modulus in the 7 directions thus obtained are compared, and the largest value is taken as the maximum value of the Young's modulus of the film. In the case where the width direction or the longitudinal direction cannot be specified, the first measurement direction can be arbitrarily determined, and the maximum value of the Young's modulus of the film can be determined by the same procedure.

[0046] Regarding the configuration of the laminated film of the present invention, the configuration shown in FIGS. 2 and 3 (two types and two-layer configuration) will be taken as an example for explanation. However, the layer configuration of the laminated film of the invention is not limited to this as long as the effects are not impaired. FIG. 2 is an enlarged top view of the laminated film according to an embodiment of the present invention when observed from the A layer side, and FIG. 3 is a cross-sectional view taken along the line I-I' of the laminated film of FIG. 2. The laminated film 1 of the present invention has a two types and two-layer configuration of an A layer 9 and a B layer 10, and the A layer 9 is composed of particles and a resin 12. The particles in the A layer include particles 11 contained in the A layer and particles 13 protruding from the A layer. That is, all the particles may be buried in the A layer 9, or a part of them may be exposed on the surface of the A layer 9. Convex portions 14 are formed on the surface of the A layer 9 by the particles 11 contained in the A layer and the particles 13 protruding from the A layer.

[0047] As a method for manufacturing the laminated film of the present invention, there are a method of extruding a composition for obtaining an A layer using a T-die or the like onto a sheet corresponding to the B layer to form the A layer, a method of applying a composition for obtaining a solutionized A layer with a known solvent or the like onto the B layer and drying it (hereinafter sometimes referred to as a coating method), a method of separately forming a film of a sheet corresponding to the B layer and a sheet for obtaining the A layer and then thermally laminating them, and the like. The coating method is preferable because a desired surface roughness can be easily obtained for the A layer of the laminated film.

[0048] Specifically, the following methods can be used as the coating method. First, to obtain a composition for obtaining the A layer, components for obtaining the A layer other than particles are dissolved in a known solvent (for example, toluene, methyl ethyl ketone (MEK), etc.), and then particles are added. Next, the solution containing particles is applied onto the B layer, and the solvent is removed by drying in an oven to form the A layer. The coating method of the solution is not particularly limited, and for example, a bar coating method, a comma coating method, a slit die coating method, a gravure coating method, and the like can be preferably used.

Examples

[0049] Examples are shown below to more specifically explain the present invention, but the present invention is not limited thereto.

[0050] [Measurement and Evaluation Methods] The measurements and evaluations shown in the examples were carried out under the following conditions.

[0051] (1) Rz and Rsk of Layer A The A-layer side of the laminated film was observed with a laser microscope (VK-X100, manufactured by Keyence Corporation) at a magnification of 20 times to obtain an observation image. The surface roughness of the obtained observation image was determined using the attached analysis application. Specifically, the entire surface of the observation image was designated as the evaluation area, and Rz and Rsk were calculated using a calculation formula conforming to JIS B0601:2001 without a cut-off. The same measurement was performed 10 times by changing the observation position, and the average values obtained from the 10 surface roughnesses were taken as the Rz and Rsk of Layer A.

[0052] (2) Average Particle Size of Particles in Layer A Using a laser microscope (VK-X100, manufactured by Keyence Corporation), the surface of Layer A was observed at a magnification such that 3 or more and 10 or fewer non-aggregated particles forming convex shapes with a height of 5 μm or more were within the screen, and an observation image was obtained. For the obtained observation image, a square or rectangle was drawn so as to completely enclose the non-aggregated particles in Layer A and have the smallest area. In the case of a square, the length of one side, and in the case of a rectangle, the average value of the lengths of the long side and the short side were taken as the particle diameter of the particle. The measurement was performed for all non-aggregated particles shown in the obtained observation image, and the average value excluding the maximum and minimum particle diameters was determined. Furthermore, the same measurement was performed 9 times by changing the measurement location, and the average value of the 10 obtained values was taken as the average particle size (μm) of the particles in Layer A. At this time, the selection of whether the particles form convex shapes with a height of 5 μm or more was performed using the function of the laser microscope.

[0053] (3) Mass of Layer A and Amount of Particles in Layer A The laminated film was cut into 10 cm × 10 cm pieces and weighed. Then, the cut laminated film was immersed in toluene for 30 minutes or more and taken out, and after drying, the weight of the film was measured. Next, the difference in weight before and after toluene immersion was determined and taken as the weight of layer A. Further, the particles in the toluene solution were taken out and the weight of the dried particles was measured, and the value of (particle weight) / (weight of layer A) was determined and taken as the amount of particles in layer A.

[0054] (4) Maximum value of Young's modulus A rectangular laminated film sample with dimensions of 100 mm (width direction) × 10 mm (longitudinal direction) was prepared. Using a tensile testing machine manufactured by Orientech Co., Ltd. (“Tensilon” (registered trademark) type), in accordance with ASTM-D882:1990 under the conditions of a tensile strength of 200 mm / min, a temperature of 23°C, and a humidity of 65%RH, the Young's modulus in the width direction (2-2' in Figure 1) was measured. The same measurement was repeated 5 times, and the average value of the obtained values was taken as the Young's modulus in the width direction. Subsequently, the sample was cut out in the same manner so that the measurement direction was the direction rotated clockwise by 15° within the film plane from the width direction, and the measurement was performed in the same way. Thereafter, as shown in Figure 1, the measurement direction was shifted by 15° clockwise (4-4' → 8-8' (longitudinal direction) in Figure 1), and the Young's modulus was measured in the same way. The maximum value of the Young's modulus values in the 7 directions thus obtained was taken as the maximum value (MPa) of the Young's modulus of the laminated film.

[0055] (5) Thickness of layer B The laminated film was cut parallel to the thickness direction at a knife tilt angle of 3° using a microtome. Then, the cross-section of layer B was observed using a scanning electron microscope, and the thickness of layer B was measured using the length measurement function of the microscope at locations where no particles were present. Thereafter, the same measurement was performed 9 times with different sampling positions, and the average value of the thickness of layer B at the total 10 locations obtained was taken as the thickness (μm) of layer B of the laminated film.

[0056] (6) Peel strength with respect to cloth A rectangular laminated film sample with dimensions of 10 mm (width direction) × 100 mm (longitudinal direction) was obtained. With the layer (A layer) having a high content of the adhesive resin on the lower side, the laminated film sample was placed on a white polyester cloth (hereinafter sometimes simply referred to as cloth) conforming to JIS L 0803:2011, and a laminating roller with a load of 1 kg was reciprocated once to bring the two into close contact. Then, the film sample was peeled off from the short side at a tensile speed of 300 mm / min, and the peel strength with respect to the cloth was measured by the method specified in JIS Z 0237:2009. The same measurement was performed 5 times, and the average value of the obtained values was taken as the peel strength (N / cm) of the A layer with respect to the cloth. Usually, to determine the A layer, it is necessary to measure the peel strength with respect to the cloth on both sides, confirm that the difference between the two is 0.05 N / cm or more, and then determine the outermost layer on the side with a relatively large peel strength with respect to the cloth as the A layer. However, in this example and the comparative example, since it is clear from the layer composition that the layer with a high content of the adhesive resin corresponds to the A layer, this procedure was omitted.

[0057] (8) Coefficient of friction of the A layer The film was cut into a square size of 50 mm (width direction) × 150 mm (longitudinal direction) to obtain a measurement sample. The coefficient of friction was measured under the following conditions using a roughness / friction sensation tester (KES-SESRU, manufactured by Kato Tech Co., Ltd.). The measurement was performed 5 times by changing the measurement position, and the average value was taken as the coefficient of friction of the A layer. [Measurement conditions] Friction terminal type: fingerprint type Friction terminal load: 25 gf Speed: 5 mm / sec.

[0058] [Adhesive layer resin of the A layer] (A1) Adhesive layer solution (a mixture of toluene, styrene-isoprene-styrene copolymer, and adhesive resin (petroleum resin, terpene resin, terpene phenol resin), GR-1025M-1, manufactured by Big Technos Co., Ltd.) (A2) Adhesive layer solution (a mixture of toluene, styrene-isoprene-styrene copolymer, and adhesive resin (terpene resin, rosin-based resin, phenol resin), GR-1045M-1, manufactured by Big Technos Co., Ltd.) [Diluent Solvent for Layer A] (B1) Ethyl Acetate [Particles in Layer A] (C1) Polyethylene Particles (XM - 330, average particle size 65 μm, manufactured by Mitsui Chemicals, Inc.) (C2) Polyethylene Particles (XM - 220, average particle size 30 μm, manufactured by Mitsui Chemicals, Inc.) [Coloring Pigment in Layer A] (D1) Titanium Oxide (R - 101, manufactured by DuPont) [Layer B] (PET) Polyester Film (4F56, manufactured by Toray Industries, Inc.) (PE) Polyethylene Film (PFL - 10A, manufactured by Toyo Heisei Polymer Co., Ltd.).

[0059] (Example 1) The pressure - sensitive adhesive layer resin, diluent solvent, particles, and coloring pigment were mixed in the formulations shown in Table 1 to obtain a solution for forming Layer A. Then, per 1 m 2 when it was a laminated film (hereinafter simply referred to as "the mass of Layer A" including the table), the mass of Layer A was 10 g / m 2 The solution was applied onto the film of Layer B with a bar coater and dried at 80°C for 1 minute to obtain a laminated film. The physical properties and evaluation results of the obtained laminated film are shown in Table 1.

[0060] (Examples 2 - 9, Comparative Examples 1 - 3) A laminated film was obtained in the same manner as in Example 1, except that the composition of the solution for forming Layer A and Layer B were as described in Table 1. The physical properties and evaluation results of the obtained film are shown in Table 1.

[0061]

Table 1

Industrial Applicability

[0062] According to the present invention, it is possible to provide a laminated film that has mechanical properties necessary for use as a film, is excellent in adhesion to cloth and the like and tactile properties, and is less likely to cause particle dropout or embedding during storage and use. The laminated film of the present invention can be preferably used in applications that require adhesion and handling properties to cloth and the like, such as medical and sanitary materials such as back sheets of absorbent articles such as bed sheets, pillow covers, sanitary napkins, and paper diapers.

Explanation of Signs

[0063] 1: Laminated film 2-2’: Width direction 3-3’: Direction rotated 15° clockwise with respect to the width direction in the film plane 4-4’: Direction rotated 15° clockwise with respect to 3-3’ in the film plane 5-5’: Direction rotated 15° clockwise with respect to 4-4’ in the film plane 6-6’: Direction rotated 15° clockwise with respect to 5-5’ in the film plane 7-7’: Direction rotated 15° clockwise with respect to 6-6’ in the film plane 8-8’: Longitudinal direction 9: A layer 10: B layer 11: Particles contained in the A layer 12: Resin 13: Particles protruding from the A layer 14: Convex portion

Claims

Claim 1 A laminated film having different peel strengths on both sides with respect to a cloth. When the outermost layer on the side with a relatively high peel strength with respect to the cloth is defined as layer A, the surface of layer A contains a resin and particles. When a rosin-based resin, a terpene-based resin, and a petroleum-based resin are used as the adhesive resin, layer A contains at least one adhesive resin and a thermoplastic elastomer. The particles contain a polyolefin resin. The particles are spherical. The average particle diameter of the particles is 10 μm or more and 100 μm or less. The content of the particles is 10% by mass or more and 55% by mass or less. The maximum roughness (Rz) of the surface roughness of layer A is 80 μm or more and 200 μm or less, and the skewness (Rsk) is 1.00 or more and 4.00 or less. A laminated film characterized by the above. Claim 2 The laminated film according to claim 1, characterized in that the average particle diameter of the particles contained in layer A is 10 μm or more and 100 μm or less. Claim 3 The laminated film according to claim 1 or 2, characterized in that the amount of the particles contained in layer A is 10% by mass or more and 55% by mass or less. Claim 4 The laminated film according to any one of claims 1 to 3, characterized in that the maximum value of the Young's modulus is 50 MPa or more and 2000 MPa or less. Claim 5 The laminated film according to any one of claims 1 to 4, characterized in that when the outermost layer on the side opposite to layer A is defined as layer B, layer A contains more of the adhesive resin than layer B.

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