JP2023079117A - Laminated film, coat film, and adhesive label - Google Patents

Abstract

To provide an adhesive label which has a small amount of carbon dioxide gas, has high whiteness, and leaves little adhesive remaining in an adherend when peeled, and a laminated film and a coat film used in the same.SOLUTION: A laminated film has a base material layer, and a first surface layer on one surface of the base material layer. The laminated film contains a porous stretched film containing an olefinic resin and an inorganic filler. The olefinic resin contains a propylene-based resin, and the propylene-based resin contains a biomass-derived propylene-based resin. The first surface layer has a porosity of 40% or less.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to laminated films, coated films and adhesive labels.

Conventionally, resin films have been widely used as printing paper for labels, wrapping paper, posters, calendars, catalogs, advertisements, and the like. In particular, resin films are in high demand as labels that can be used outdoors because of their excellent water resistance.

A label is usually provided with a printed layer on one side of a resin film for information, design, or the like. Furthermore, a pressure-sensitive adhesive layer is provided on the other surface of the resin film, and the film may be used as a pressure-sensitive adhesive label to be attached to an adherend. Patent Literature 1 discloses a resin film that can be used as a base material for such adhesive labels.

On the other hand, as a countermeasure against global warming, there is a demand for an environment in which the dependence on oil is eliminated and the amount of carbon dioxide gas emitted is low. Patent Literature 2 proposes a resin film in which petroleum-derived polyolefin is used in combination with biomass-derived polyolefin.

JP-A-6-102826 JP 2012-251006 A

When the adhesive label is peeled off from the adherend, if the adhesive remains on the adherend, it tends to cause contamination. Adhesive labels are also required to have a high degree of whiteness so that printed content can be displayed more clearly. Regarding the resin film used for adhesive labels, there is room for further reducing the amount of carbon dioxide gas emitted during the manufacturing process by improving the materials used or the film structure.

The present invention provides a pressure-sensitive adhesive label that emits a small amount of carbon dioxide gas, has a high degree of whiteness, and leaves a small amount of pressure-sensitive adhesive on the adherend when peeled off, and a laminated film and a coated film used therefor. With the goal.

As a result of intensive studies by the present inventors to solve the above problems, the above problems can be solved by using a porous stretched film containing a resin component derived from biomass and adjusting the porosity of the surface layer to be relatively small. I found that the problem can be solved, and completed the present invention.
That is, the present invention is as follows.

[1] A laminated film comprising a substrate layer and a first surface layer on one surface of the substrate layer,
including a porous stretched film containing an olefinic resin and an inorganic filler;
The olefin-based resin contains a propylene-based resin,
The propylene-based resin includes a biomass-derived propylene-based resin,
A laminated film, wherein the first surface layer has a porosity of 40% or less.

[2] The laminated film according to [1] above, wherein the propylene-based resin further contains a petroleum-derived propylene-based resin.

[3] The laminated film according to [1] or [2] above, wherein the olefin-based resin further contains an ethylene-based resin.

[4] The laminated film according to [3] above, wherein the ethylene-based resin contains a biomass-derived ethylene-based resin.

[5] The laminated film according to the above [3] or [4], wherein the ethylene-based resin contains a petroleum-derived ethylene-based resin.

[6] The laminated film according to any one of [1] to [5] above, wherein the first surface layer has a porosity of 0.1 to 30%.

[7] comprising a second surface layer on the other surface of the base layer;
The laminated film according to any one of [1] to [6] above, wherein the second surface layer has a porosity of 30 to 55%.

[8] The laminated film according to any one of [1] to [7] above;
a coat layer on at least one surface of the laminated film,
A coat film, wherein the coat layer contains a (meth)acrylic ester-based resin.

[9] The laminated film according to any one of [1] to [7] above;
and an adhesive layer provided on one surface of the laminated film.

ADVANTAGE OF THE INVENTION According to the present invention, a pressure-sensitive adhesive label that emits a small amount of carbon dioxide gas, has a high degree of whiteness, and leaves a small amount of pressure-sensitive adhesive on the adherend when peeled off, and a laminated film and a coated film used therefor are provided. can do.

1 is a cross-sectional view showing an example of an adhesive label of the present invention; FIG.

The laminated film, coated film and pressure-sensitive adhesive label of the present invention are described in detail below. The following description is an example (representative example) of the present invention, and the present invention is not limited thereto.

In the following description, the description of "(meth)acrylic" indicates both acrylic and methacrylic.

(Laminated film)
The laminated film of the present invention comprises a substrate layer and a first surface layer on one side of the substrate layer. The laminated film of the present invention includes a stretched film made porous by stretching a resin film containing an olefinic resin and an inorganic filler. The porous stretched film is stretched at least uniaxially, but from the viewpoint of increasing the porosity and mechanical strength of the film, it is more preferably a stretched film biaxially stretched.

In the porous stretched film, the whiteness of the laminated film is increased due to the large number of pores formed with the inorganic filler as the nucleus. Therefore, it is possible to provide a laminated film capable of clearly displaying printed contents. In addition, due to the porosity, the resin component in the laminated film is replaced with air with a carbon dioxide emission coefficient of zero or an inorganic filler with a lower carbon dioxide emission coefficient than the resin, so the unit volume is less than that of a resin film without pores. The amount of resin component used per unit is small. A considerable amount of carbon dioxide gas is emitted from the resin component during its manufacturing process, and it is possible to reduce the amount of carbon dioxide gas emitted by reducing the amount used.

Moreover, in the laminated film of the present invention, the olefin-based resin includes a propylene-based resin. Propylene-based resins are harder than ethylene-based resins and the like, and have the characteristic of being more likely to form more pores by stretching. The porosity of the stretched film can be increased by the propylene-based resin having such characteristics, and the amount of carbon dioxide gas emitted can be easily reduced.

Further, the propylene-based resin includes a biomass-derived propylene-based resin. In the present invention, biomass means resources derived from biomass. Biomass can include the raw material plant itself, as well as oils and sugars derived from the same plant. Since the plant used as a raw material absorbs carbon dioxide gas during the growth stage, compared to petroleum-derived propylene-based resins that do not absorb such carbon dioxide gas, the production process of biomass-derived propylene-based resins Carbon dioxide gas emission factor is small. Therefore, the amount of carbon dioxide gas emitted per unit volume of the laminated film can be reduced, and the environmental load can be further reduced.

Thus, according to the present invention, the amount of resin components that emit carbon dioxide gas in the manufacturing process is reduced, and among the resin components, petroleum-derived resins with relatively high carbon dioxide gas emission coefficients are used. The amount of resin component used is small. It is possible to effectively reduce the emission of carbon dioxide gas, and to provide a laminated film with low environmental load.

Moreover, in the laminated film of the present invention, the porosity of the first surface layer is 40% or less. When a pressure-sensitive adhesive layer is formed on such a first surface layer and the laminated film of the present invention is used as a substrate for a pressure-sensitive adhesive label, the adhesion between the first surface layer and the pressure-sensitive adhesive layer is improved. Even if the pressure-sensitive adhesive label is attached to the adherend and then peeled off, the pressure-sensitive adhesive layer can be easily maintained in close contact with the first surface layer, and the pressure-sensitive adhesive layer remaining on the adherend can be reduced. Therefore, it is possible to provide a pressure-sensitive adhesive label that is easy to peel off and does not easily get dirty after peeling.

The laminated film can include one or more layers of the porous stretched film containing the above biomass-derived propylene-based resin and filler. From the viewpoint of reducing the environmental load, it is preferable that there are many layers of such a porous stretched film, and it is more preferable that all the layers are such a porous stretched film.
Each layer will be described below.

(Base material layer)
The base layer imparts stiffness or rigidity to the laminated film, and can improve transportability during printing. From the viewpoint of whiteness, the substrate layer is preferably a porous stretched film containing an olefin resin and an inorganic filler, and from the viewpoint of reducing the environmental load, it contains a biomass-derived propylene resin as the olefin resin. preferably. .

<Olefin resin>
Examples of olefinic resins include propylene-based resins, ethylene-based resins, polymethyl-1-pentene, and the like. Among them, the olefin-based resin preferably contains a propylene-based resin as a main component because the propylene-based resin is excellent in mechanical strength. In this specification, the main component refers to a component whose content in the layer is 50% by mass or more.

<Propylene resin>
Propylene-based resins include, for example, propylene homopolymers such as isotactic homopolypropylene resins and syndiotactic homopolypropylene resins obtained by homopolymerizing propylene; propylene-ethylene copolymers obtained by copolymerizing propylene as a main component with ethylene; Propylene α obtained by copolymerizing propylene as the main component with α-olefins such as 1-butene, 1-hexene, 1-heptene, 1-octene, and 4-methyl-1-pentene, which are alkylenes with 4 or more carbon atoms. - Olefin copolymers, etc.; include propylene/ethylene/α-olefin copolymers mainly composed of propylene. The propylene copolymer may be a binary system or a multicomponent system of ternary or higher, and may be a random copolymer, a block copolymer, or a reactor blend copolymer. Specifically, propylene homopolymer, propylene/ethylene copolymer, propylene/1-butene copolymer, propylene/ethylene/1-butene copolymer, propylene/4-methyl-1-pentene copolymer, A propylene/3-methyl-1-pentene copolymer or a propylene/ethylene/3-methyl-1-pentene copolymer may be mentioned. Among these, crystalline homopolypropylene resins obtained by homopolymerizing propylene are preferred, and isotactic homopolypropylene resins are more preferred, from the viewpoint of film stretchability.

As propylene resin, depending on the manufacturing method, polypropylene produced by Ziegler-Natta polymerization catalyst, polypropylene produced by metallocene polymerization catalyst (single-site polymerization catalyst), olefinic thermoplastic elastomer also called reactor TPO, or high melt tension polypropylene. etc.

The melt flow rate (MFR) conforming to JIS K7210:2014 (temperature of 230° C., load of 2.16 kg) for propylene-based resin is 0.2 to 20 g/10 from the viewpoint of improving the mechanical strength of the porous stretched film. minutes, more preferably 1 to 10 g/10 minutes, even more preferably 2 to 6 g/10 minutes.

<<Biomass-derived propylene-based resin>>
In the present invention, one or more of the above propylene-based resins can be used for the porous stretched film, and part or all of the resin is a biomass-derived propylene-based resin.
The biomass-derived propylene-based resin is a propylene polymer using propylene, which is derived from biomass as a raw material, as a monomer. Some or all of the propylene used as a monomer may be derived from biomass, and some or all of the ethylene or α-olefin used as comonomers may be derived from biomass.

From the viewpoint of improving the degree of biomass, the biomass-derived propylene-based resin preferably contains a propylene homopolymer containing biomass-derived propylene, and more preferably contains a homopolymer composed of biomass-derived propylene.

Biomass-derived propylene, which is a raw material for propylene-based resin, can be produced from biomass-derived ethylene and the same equivalent amount of butene through a metathesis reaction.

Biomass-derived propylene as a raw material can be produced, for example, by producing isopropanol from sugar produced by biomass fermentation through a fermentation process including a glycolytic process, and then subjecting the same isopropanol to a dehydration reaction. Sugars produced by fermentation include, for example, maltose, sucrose, glucose and fructose. In the fermentation process, bacteria of the genus Clostridium or bacteria of the genus Clostridium, or E. coli, yeast, or the like into which genes derived from bacteria of the genus Clostridium have been introduced act on these sugars in the fermentation process.

Biomass includes, for example, rapeseed, soybean, oil palm fruit, oil palm seed, sunflower seed, cottonseed (cotton seed), peanut, olive fruit, corn germ, coconut endosperm, sesame, perilla sesame, linseed. , plants such as castor, rice bran, safflower seeds, and grape seeds, or vegetable oils obtained by squeezing from plants.

Examples of commercially available biomass-derived propylene resins include HC101BF (MFR: 3.2 g/10 minutes), HC110BF (MFR: 3.2 g/10 minutes), and Bormed HE125MO (MFR: 12 g/10 minutes) manufactured by Borealis. ), HF840MO (MFR: 19 g/10 min), HG430MO (MFR: 25 g/10 min), HJ325MO (MFR: 50 g/10 min), or Circulen HP456J manufactured by Rondelbassell (MFR: 3.4 g/10 min), Circulen HP483R (MFR: 27g/10min), Circulen HP500N (MFR: 12g/10min), Circulen HP501H (MFR: 2.1g/10min), Circulen EP310M HP (MFR: 7.5g/10min), Circu len EP540P (MFR: 15 g/10 minutes) or the like can be used.

<<Petroleum-derived propylene resin>>
A petroleum-derived propylene-based resin can also be used together with the biomass-derived propylene-based resin. A petroleum-derived propylene-based resin is a propylene polymer obtained by using propylene, whose starting material is petroleum, as a monomer. Petroleum-derived propylene-based resins are inexpensive and readily available. In addition, there are a wide variety of these products, including those whose melt viscosity is increased by adjusting the polymerization conditions and those which are chemically modified. Therefore, when these are used together with a biomass-derived propylene-based resin, it is easy to adjust the moldability and quality of the porous stretched film.

<<Mass ratio of biomass-derived propylene-based resin to petroleum-derived propylene-based resin>>
The mass ratio of the biomass-derived propylene-based resin to the petroleum-derived propylene-based resin (biomass-derived propylene-based resin: petroleum-derived propylene-based resin) is preferably 1:99 to 99:1. From the viewpoint of increasing the degree of biomass and reducing the amount of carbon dioxide gas emitted, it is preferable that the content of the biomass-derived propylene-based resin is large. On the other hand, biomass-derived resins are more expensive than petroleum-derived resins, so from the viewpoint of reducing production costs, it is preferable that the content of the petroleum-derived propylene-based resin is large. Therefore, the mass ratio is more preferably 5:95 to 70:30, more preferably 10:90 to 40:60.

<Ethylene resin>
The olefin resin used for the porous stretched film preferably further contains an ethylene resin. By using a propylene-based resin and an ethylene-based resin in combination, the stretchability of the film is improved, and a film with less stretch unevenness and good appearance can be easily obtained. In addition, by using an ethylene-based resin that melts more easily than a propylene-based resin, it becomes easier to stretch in a molten state. The formation of fibril-like pores is facilitated, the pore-formability is improved, and the manufacturing cost of the porous stretched film can be reduced.

When an ethylene-based resin is used in combination, if the amount of the propylene-based resin in the total resin amount of the porous stretched film is the majority, a sea-island structure in which the propylene-based resin is the sea and the ethylene-based resin is the islands is likely to be formed. The stress applied during stretching of the resin composition causes not only shearing at the interface between the resin and the inorganic filler, but also shearing at the interface of the sea-island structure, so that a large number of pores can be formed with a weaker force. It becomes possible.

Examples of ethylene-based resins include high-density polyethylene resins, medium-density polyethylene resins, high-pressure low-density polyethylene resins, and linear low-density polyethylene resins. Among these, a high-density polyethylene resin having a density of 0.950 to 0.965 g/cm ³ is preferable from the viewpoint of film formability.

When ethylene resin is used in combination with propylene resin, ethylene resin with a melt flow rate close to that of propylene resin is selected from the viewpoint of facilitating uniform kneading or from the viewpoint of facilitating the formation of a dense phase-separated structure during melt kneading. preferably. The melt flow rate (MFR) of such ethylene-based resins according to JIS K7210:2014 (temperature 190° C., 2.16 kg load) is preferably 0.2 to 20 g/10 minutes, and 1 to 10 g/ It is preferably 10 minutes, more preferably 2 to 8 g/10 minutes.

<<Biomass-derived ethylene-based resin>>
The ethylene-based resin contained in the porous stretched film in the present invention may be either petroleum-derived or biomass-derived, but preferably contains biomass-derived ethylene-based resin from the viewpoint of further reducing the environmental load. The biomass-derived ethylene-based resin is an ethylene polymer obtained by using biomass-derived ethylene as a monomer.

Ethylene derived from biomass can be produced, for example, by dehydration of ethanol produced by fermentation of biomass as described above. The α-olefin used as a comonomer for the biomass-derived ethylene-based resin may be a biomass-derived α-olefin or a petroleum-derived α-olefin.

Examples of biomass-derived high-density polyethylene resins include SHC7260 (MFR; 7.2 g/10 min, density; 0.959 g/cm ³ ) and SHD7255LSL (MFR; 4.5 g/10 min, manufactured by Braskem). Commercial products such as density: 0.954 g/cm ³ ) and SGE7252 (MFR: 2.2 g/10 min, density: 0.953 g/cm ³ ) can also be used. The MFR of the Braskem product is a measured value according to JIS K7210:2014, and the density is a measured value according to ASTM D1505/D792.

<<Petroleum-derived ethylene resin>>
A petroleum-derived ethylene-based resin is an ethylene polymer obtained by using ethylene, which is petroleum as a raw material, as a monomer. Since petroleum-derived ethylene-based resins are readily available and have a wide variety of types, it is easy to adjust the moldability and quality of the porous stretched film, which is preferable.

The petroleum-derived and biomass-derived ethylene-based resins can be produced in the same manner, except that petroleum or biomass is used as the raw material. Ziegler-Natta catalysts, metallocene catalysts and the like are generally used as catalysts for the polymerization reaction in the production.

<<Amount ratio of propylene-based resin and ethylene-based resin>>
The mass ratio of the propylene-based resin and the ethylene-based resin in the resin component constituting the porous stretched film (total amount of biomass-derived and petroleum-derived propylene-based resin: total amount of biomass-derived and petroleum-derived ethylene-based resin) From the viewpoint of formability, the ratio is preferably 1:99 to 99:1, more preferably 10:90 to 97:3, even more preferably 65:35 to 95:5.

<<Quantity ratio of resin component derived from biomass and resin component derived from petroleum>>
As described above, biomass-derived propylene-based resins can be used in combination with petroleum-derived propylene-based resins and biomass-derived and petroleum-derived ethylene-based resins. The mass ratio of the total amount of the resin components combined to the total amount of the resin components combined with the petroleum-derived propylene-based resin and the ethylene-based resin is preferably 1:99 to 99:1. The lower limit of the content ratio of the biomass-derived resin component at the same mass ratio is more preferably 5:95, and the upper limit of the content ratio of the biomass-derived resin component at the same mass ratio is 45:55. more preferred. Within this range, it is possible to increase the mass ratio of the biomass-derived resin component, increase the degree of biomass, and effectively reduce the amount of carbon dioxide gas emitted.

From the viewpoint of compatibility between biomass degree and cost, the olefin resin used for the porous stretched film is 5 to 90 parts by mass of biomass-derived propylene resin, 40 to 90 parts by mass of petroleum-derived propylene resin, and 40 to 90 parts by mass of biomass-derived propylene resin. It preferably contains 0 to 20 parts by mass of an ethylene resin and 0 to 20 parts by mass of a petroleum-derived ethylene resin.

In addition, the porous stretched film may be olefin-based resins other than the above-mentioned propylene-based resins and ethylene-based resins, ester-based resins, styrene-based resins, amide-based resins, (meta- ) may contain acrylic resins, urethane resins, and the like.

<Inorganic filler>
Inorganic fillers that can be used in porous stretched films include inorganic particles such as calcium carbonate, titanium oxide, calcined clay, talc, barium sulfate, aluminum sulfate, silica, zinc oxide, magnesium oxide, or diatomaceous earth. Blending the inorganic filler facilitates the formation of porosity by stretching. Among them, fine powder of calcium carbonate, clay or diatomaceous earth is preferable because it has good pore moldability and is inexpensive. In particular, fine powder of calcium carbonate is preferable because it is easy to adjust the porosity because there are many types of calcium carbonate, and it is easy to adjust the whiteness of the porous stretched film.

The average particle diameter of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, from the viewpoint of ease of forming pores. From the viewpoint of increasing the strength of the porous stretched film, the average particle size of the inorganic filler is preferably 10 μm or less, more preferably 8 μm or less. Therefore, the average particle size of the inorganic filler is preferably 0.01-10 μm, more preferably 0.05-8 μm.
The average particle size of the inorganic filler is the volume average particle size measured with a particle size distribution meter using laser diffraction.

The content of the inorganic filler with respect to 100 parts by mass of the total resin components in the porous stretched film is preferably 3 to 233 parts by mass.

<Other additives>
The porous stretched film may contain additives such as heat stabilizers (antioxidants), light stabilizers, dispersants and lubricants, if necessary. When the porous stretched film contains a heat stabilizer, it usually contains 0.001 to 1% by weight of the heat stabilizer. Examples of heat stabilizers include sterically hindered phenol-based, phosphorus-based, and amine-based stabilizers. When the porous stretched film uses a light stabilizer, it usually contains 0.001 to 1% by weight of the light stabilizer. Examples of light stabilizers include sterically hindered amine-based, benzotriazole-based, and benzophenone-based light stabilizers. Dispersants or lubricants can be used, for example, for the purpose of dispersing inorganic fillers. The amount of dispersant or lubricant used in the porous stretched film is usually within the range of 0.01 to 4% by weight. Examples of dispersants or lubricants include silane coupling agents, higher fatty acids such as oleic acid and stearic acid, metal soaps, polyacrylic acid, polymethacrylic acid, and salts thereof.

<Porosity>
The higher the porosity of the stretched porous film, the more whiteness can be imparted to the laminated film, and the more the ratio of the resin component in the stretched porous film is reduced, the more the amount of carbon dioxide gas emitted can be reduced. Therefore, the porosity of the porous stretched film that constitutes the substrate layer is preferably 3% or more, more preferably 5% or more, and even more preferably 10% or more. From the viewpoint of imparting mechanical strength such as tear resistance, the porosity is preferably 55% or less, more preferably 45% or less, and even more preferably 42% or less.
The porosity can be adjusted by the average particle size of the filler, the composition of the film such as the mass ratio of the propylene-based resin and the ethylene-based resin, the stretching conditions such as the stretching temperature or the stretching ratio, and the like.

The porosity can be obtained from the ratio of the area occupied by pores in a certain region of the cross section of the film observed with an electron microscope. Specifically, an arbitrary portion of the film to be measured is cut, embedded in epoxy resin, and solidified. Using a microtome, the film to be measured is cut perpendicularly to the surface direction of the film, and the cut surface is attached to the observation sample stand so that the observation surface is the observation surface. Vapor-deposit gold or gold-palladium on the observation surface, observe the pores in the film at any magnification that is easy to observe with an electron microscope (for example, magnification of 500 times to 3000 times), and image the observed area. Import as data. The obtained image data is subjected to image processing by an image analysis device, and the area ratio (%) of the void portions in a certain region of the film is obtained and defined as the porosity (%). In this case, the porosity can be obtained by averaging the measured values obtained by observation at arbitrary 10 or more points.

(First surface layer)
The first surface layer can improve the strength of the laminated film and enhance tear resistance and the like. Further, when the laminated film is used as an adhesive label, the adhesion between the adhesive layer and the laminated film can be easily adjusted by the first surface layer.

The first surface layer is, like the substrate layer, a porous stretched film containing an olefin resin and an inorganic filler from the viewpoint of pore formation or reduction of environmental load. It preferably contains a propylene-based resin. The materials used for the first surface layer and the base layer and their compounding amounts may be the same or different.

The olefinic resins that can be used for the first surface layer include the same olefinic resins as those used for the substrate layer described above, and one of them can be used alone or two or more of them can be used in combination. The first surface layer preferably contains two or more propylene-based resins having different melt flow rates from the viewpoint of adhesion to the adhesive layer. For example, the first surface layer comprises a first propylene-based resin having a melt flow rate of 0.1 g/10 min or more and less than 5.0 g/10 min, and a melt flow rate of 5.0 g/10 min or more and 20 g/10 min or less. A second propylene-based resin having a rate may be included. From the viewpoint of improving the mechanical strength, a propylene-based resin having a melting point (peak temperature of DSC curve) of 130 to 210° C. is preferable as the propylene-based resin used for the first surface layer. Among them, the melting point (peak temperature of the DSC curve) is 155 to 174 ° C., the melt flow rate (MFR) in accordance with JIS K7210: 2014 is 0.5 to 20 g / 10 minutes, and the crystallinity is 45 to A propylene homopolymer that is 70% is more preferred.

Examples of inorganic fillers that can be used in the first surface layer include inorganic fillers similar to those used in the base material layer, as well as precipitated calcium carbonate.

From the viewpoint of improving adhesion with the adhesive layer, the average particle size of the inorganic filler used in the first surface layer is preferably 6 μm or less, more preferably 4 μm or less, and even more preferably 2 μm or less. From the viewpoint of pore formation, the average particle diameter is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.07 μm or more.

The content of the inorganic filler in the first surface layer is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, and 40% by mass, from the viewpoint of improving adhesion with the adhesive layer. % or less is more preferable, and 30 mass % or less is particularly preferable. From the viewpoint of increasing the porosity and reducing the amount of carbon dioxide gas emitted, the content is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more.

<Porosity>
As described above, the porosity of the first surface layer is 40% or less. From the viewpoint of improving adhesion with the pressure-sensitive adhesive layer, the porosity is preferably 35% or less, more preferably 30% or less, even more preferably 25% or less, and particularly preferably 20% by mass or less. From the viewpoint of reducing the environmental load, etc., the porosity is preferably 0.1% or more, more preferably 5% or more, and even more preferably 10% or more.
The porosity can be adjusted by the average particle size of the filler, the composition of the film, stretching conditions, and the like.

<Thickness>
From the viewpoint of improving film strength, the thickness of the first surface layer is preferably 1 μm or more, more preferably 1.5 μm or more. Moreover, from the viewpoint of improving handling properties, the thickness is preferably 50 μm or less, more preferably 20 μm or less.

(Second surface layer)
The laminated film of the present invention can have a second surface layer on the surface opposite the first surface layer. The strength of the laminated film can be further improved by the second surface layer, and tear resistance and the like can be further improved. Further, when a printed layer made of ink is provided on the laminated film by printing, the second surface layer facilitates enhancing adhesion to the ink.

The second surface layer can be constructed similarly to the first surface layer. From the viewpoint of pore formation or reduction of environmental load, the second surface layer is a porous stretched film containing an olefin-based resin and an inorganic filler, and the olefin-based resin contains a biomass-derived propylene-based resin. is preferred. The olefinic resin and inorganic filler that can be used for the second surface layer include the same materials as for the first surface layer, and the preferred materials are also the same as those for the first surface layer. The materials used for the first surface layer and the second surface layer may be the same or different.

From the viewpoint of improving the scratch resistance of the printed layer, the content of the inorganic filler in the second surface layer is preferably 70% by mass or less, more preferably 65% by mass or less, even more preferably 60% by mass or less, and 55% by mass. The following are more preferable, and 50% by mass or less is particularly preferable. From the viewpoint of increasing the porosity and reducing the amount of carbon dioxide gas emitted, the content is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more.

<Porosity>
From the viewpoint of enhancing adhesion with ink by the anchoring effect, the porosity of the second surface layer is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more (or more than 30%). , more preferably 35% or more, and particularly preferably 40% or more. From the viewpoint of improving tear resistance, the porosity of the second surface layer is preferably 55% or less, more preferably 50% or less.
The porosity can be adjusted by the average particle size of the filler, the composition of the film, stretching conditions, and the like.

<Thickness>
From the viewpoint of image clarity in printing, the thickness of the second surface layer is preferably 20 μm or more, more preferably 25 μm or more. Moreover, from the viewpoint of improving handling properties, the thickness is preferably 100 μm or less, more preferably 50 μm or less.

(other layers)
The laminated film of the present invention can have layers other than the above-described first surface layer and second surface layer depending on the application or function. For example, from the viewpoint of increasing the degree of whiteness, a propylene-based resin film containing 8 to 55% by mass of an inorganic filler can be provided as an intermediate layer between the substrate layer and the first surface layer or the second surface layer.

(Biomass degree)
The biomass degree in the laminated film is preferably 1 to 97%. The higher the degree of biomass, the smaller the amount of carbon dioxide gas emitted during the manufacturing process of the laminated film, and the smaller the environmental load. Therefore, the biomass degree is more preferably 10% or more, and even more preferably 25% or more. On the other hand, since biomass-derived raw materials are more expensive than petroleum-derived raw materials, from the viewpoint of reducing manufacturing costs, the biomass degree is preferably 90% or less, more preferably 80% or less, and further preferably 70% or less. 60% or less is particularly preferred, and less than 50% is most preferred.

The biomass degree is calculated from the content of biomass-derived raw materials in the laminated film. Specifically, it is the mass ratio of the biomass-derived olefinic resin in the entire laminated film, and is calculated from the content of the biomass-derived olefinic resin.
Petroleum-derived propylene-based resins or ethylene-based resins do not contain radioactive carbon (14C) with a mass number of 14, whereas biomass-derived propylene-based resins or ethylene-based resins contain ^14C at a certain ratio. A distinction between the two is possible. The ratio of the biomass-derived raw material in the resin component of the laminated film can be calculated based on the measured ¹⁴ C content.

(whiteness)
The laminated film of the present invention preferably has a whiteness of 95% or more. Such a laminated film has a good appearance of printed characters, figures, etc., and can provide a printed material with an excellent appearance.
The whiteness can be measured according to JIS L1015:1999.

(Application)
The laminated film of the present invention can be used as printing paper or writing paper. That is, the first surface layer or the second surface layer of the laminated film is printable or writable. Examples of printing methods that can be used include ultraviolet curing offset printing, solvent offset printing, electrophotography, sublimation heat transfer, fusion heat transfer, direct thermal, letterpress printing, gravure printing, and flexographic printing. It is possible to print in a sheet form or a roll form by a rotary method. Among them, ultraviolet curing offset printing is preferable because the second surface layer has high adhesion to ultraviolet curing ink.

The laminated film of the present invention can also be used as a base material for adhesive labels. Since the first surface has high adhesion to the pressure-sensitive adhesive layer, it is preferable that the pressure-sensitive adhesive layer is provided on the first surface layer of the laminated film.

(Method for manufacturing laminated film)
The method for producing the laminated film of the present invention is not particularly limited, and the laminated film can be produced by molding and laminating each layer of film. A porous stretched film can be formed by molding a film from a resin composition containing an olefin resin and an inorganic filler and stretching the film.

<Film molding>
Examples of the method for forming a single layer film include cast molding, calendar molding, rolling molding, or inflation molding in which a molten resin is extruded into a sheet using a T die, I die, or the like connected to a screw extruder.

Methods for forming a multilayer film include a coextrusion method, an extrusion lamination method, a coating method, and the like, and these methods can also be combined. In the coextrusion method, resin compositions for each layer melted and kneaded in separate extruders are laminated and extruded in a feed block or multi-manifold, and film formation and lamination are performed in parallel. Extrusion lamination processes involve extruding a resin composition onto a preformed film to laminate another film. The coating method forms and laminates another film by coating a resin solution, emulsion or dispersion onto a film and drying it.

<Stretching>
The film may be stretched before lamination or after lamination. Since the first surface layer or the second surface layer is relatively thin, it is preferable to stretch it after laminating it on the substrate layer instead of stretching it as a single layer. As described above, when the porous stretched film is a biaxially stretched layer, the porosity is increased, the amount of carbon dioxide gas emitted can be further reduced, and the mechanical strength can be increased, which is preferable. Further, when the porous stretched film is a uniaxially stretched film, a fibril-like surface can be easily formed and ink permeability can be improved, which is preferable.

As the stretching method, for example, a longitudinal stretching method using a peripheral speed difference between roll groups, a transverse stretching method using a tenter oven, a sequential biaxial stretching method combining these, a rolling method, a simultaneous two-stretching method using a combination of a tenter oven and a pantograph. Examples include an axial stretching method and a simultaneous biaxial stretching method using a combination of a tenter oven and a linear motor. A simultaneous biaxial stretching (inflation molding) method can also be used, in which a circular die connected to a screw type extruder is used to extrude a molten resin into a tubular shape, and then air is blown into the tubular shape.

When an amorphous resin is used, the stretching temperature is preferably in the range of the glass transition temperature of the amorphous resin or higher. In the case of using a crystalline resin, the stretching temperature is preferably above the glass transition point of the non-crystalline portion of the crystalline resin and below the melting point of the crystalline portion of the crystalline resin. , preferably 2 to 60° C. lower than the melting point. Specifically, in the case of a propylene homopolymer (melting point 155-167°C), the stretching temperature is preferably 100-164°C, and in the case of a high-density polyethylene resin (melting point 121-134°C), the stretching temperature is 70-133°C. is preferred.

The stretching speed is not particularly limited, but from the viewpoint of stable stretching molding, it is preferably in the range of 20 to 350 m/min.

The draw ratio can also be appropriately determined in consideration of the properties of the resin component used. For example, when a propylene homopolymer or a propylene copolymer is used, the lower limit of the draw ratio when drawing in one direction is usually 1.1 times or more, preferably 2 times or more, and the upper limit is usually 10 times. times or less, preferably 9 times or less. On the other hand, the draw ratio in the case of biaxial stretching is an area draw ratio, and the lower limit is usually 1.5 times or more, preferably 4 times or more, and the upper limit is usually 75 times or less, preferably 50 times or less. . When another thermoplastic resin film is stretched in one direction, the lower limit of the draw ratio is usually 1.2 times or more, preferably 2 times or more, and the upper limit is usually 10 times or less, preferably 5 times or less. be. The draw ratio in biaxial stretching is an area draw ratio, and the lower limit is usually 1.5 times or more, preferably 4 times or more, and the upper limit is usually 20 times or less, preferably 12 times or less. If the draw ratio is within the above range, the desired porosity and basis weight are easily obtained, and the opacity is easily improved. In addition, the film is less likely to break, and the stretching process is more likely to be stabilized.

<Surface treatment>
The first surface layer or the second surface layer is preferably surface-treated to activate the surface. Thereby, the adhesion between the first surface layer or the second surface layer and the adjacent layers can be enhanced.
Surface treatments include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, ozone treatment, and the like, and these treatments can be combined. Among them, corona discharge treatment or flame treatment is preferable, and corona treatment is more preferable.

The amount of discharge when performing corona discharge treatment is preferably 600 J/m ² (10 W·min/m ² ) or more, more preferably 1,200 J/m ² (20 W·min/m ² ) or more. On the other hand, it is preferably 12,000 J/m ² (200 W·min/m ² ) or less, more preferably 10,800 J/m ² (180 W·min/m ² ) or less. The discharge amount when flame treatment is performed is preferably 8,000 J/m ² or more, more preferably 20,000 J/m ² or more, and preferably 200,000 J/m ² or less. It is preferably 100,000 J/m ² or less.

(coated film)
The coated film of the present invention includes the laminated film and a coat layer on at least one surface of the laminated film. Although the laminated film alone can be used as a printing paper, the coated film has high adhesion between the coated layer and the ink, so the printability is further improved. Also, by using a laminated film as a base material and providing a pressure-sensitive adhesive layer thereon, it can be used as a pressure-sensitive adhesive label. Therefore, by using the coated film as the base material of the adhesive label, the adhesion between the laminated film and the adhesive layer is enhanced through the coat layer, and the adhesive adheres even when the adhesive label is peeled off from the adherend. It is preferable because it does not easily remain on the body.

<Coating layer>
The coat layer preferably contains a (meth)acrylic acid ester resin. The (meth)acrylic acid-based resin improves the adhesion between the coat layer and the pressure-sensitive adhesive layer or ink. Such a coat layer can be formed by preparing a coating liquid for forming a coat layer containing an acrylic acid ester-based resin and applying the coating liquid to the surface of the laminated film.

From the viewpoint of improving adhesion with the pressure-sensitive adhesive layer or ink, the (meth)acrylic acid ester resin preferably has cationic properties, and more preferably has an amino group, a quaternary ammonium salt structure, or a phosphonium salt structure. , an amino group or a quaternary ammonium salt structure.

The content of the (meth)acrylic acid ester resin in the coat layer is preferably 5% by mass or more, more preferably 20% by mass or more, and still more preferably 40% by mass or more, from the viewpoint of improving adhesion with the adhesive. is. The upper limit of the content is not particularly limited, but may be 90% by mass or less, 80% by mass or less, or 70% by mass or less.

The coat layer preferably further contains an ethyleneimine polymer. Ethyleneimine-based polymers have a strong affinity with various printing inks, particularly ultraviolet curable inks, and thus easily improve printability.

The ethyleneimine-based polymer includes, for example, polyethyleneimine, poly(ethyleneimine-urea), ethyleneimine adducts of polyamine polyamides, modified products and hydroxides thereof. Modified compounds include, for example, alkyl modified compounds, cycloalkyl modified compounds, aryl modified compounds, allyl modified compounds, aralkyl modified compounds, benzyl modified compounds, cyclopentyl modified compounds, cycloaliphatic hydrocarbon modified compounds, and glycidol. Modified forms and the like can be mentioned.
These can be used individually or in combination of 2 or more types.

Epomin (trade name) manufactured by Nippon Shokubai Co., Ltd.; Polymin SK (trade name) manufactured by BASF; products can also be used.

In addition, from the viewpoint of improving the adhesion with the ink, the coat layer is composed of ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-(meth)acrylic acid copolymer. (Earth) metal salts or resin particles such as ethylene-(meth)acrylic acid ester-maleic anhydride copolymer can also be contained. The resin particles can be emulsion derived. The emulsion is a liquid obtained by dispersing the above copolymer as fine particles in an aqueous dispersion medium and emulsifying the particles. Such resin particles have a high affinity with ink.

The coat layer may contain other auxiliary components such as an antistatic agent, a cross-linking accelerator, an antiblocking agent, a pH adjuster, and an antifoaming agent, if necessary.

From the viewpoint of adhesion with the adhesive layer or ink, the thickness of the coat layer is preferably 0.01 μm or more, more preferably 0.02 μm or more, and further preferably 0.03 μm or more. preferable. From the viewpoint of suppressing cohesive failure of the coat layer, the thickness of the coat layer is preferably 7 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less.

(adhesive label)
The pressure-sensitive adhesive label of the present invention includes the laminated film and a pressure-sensitive adhesive layer on one surface of the laminated film. In the pressure-sensitive adhesive label of the present invention, it is preferred that a coat layer is provided on the laminated film. That is, the pressure-sensitive adhesive label of the present invention can also include the coat film and a pressure-sensitive adhesive layer on the coat layer of the coat film. The pressure-sensitive adhesive layer is preferably provided on the coat layer on the first surface layer side. As described above, not only is the adhesion between the adhesive layer and the coat layer high, but the adhesion between the coat layer and the first surface layer is also high, so when the adhesive label is peeled off from the adherend, the adhesive that remains on the adherend is reduced. A self-adhesive label with less agent can be provided.

FIG. 1 shows an example of an adhesive label.
As illustrated in FIG. 1, the adhesive label 30 includes a coat film 20 as a substrate and an adhesive layer 31 on one surface thereof. A printed layer 40 may be provided on the other side of the adhesive label 30 by printing. The coat film 20 has coat layers 21 on both sides of the laminate film 10 . The laminated film 10 includes a substrate layer 11 and a first surface layer 12 and a second surface layer 13 on both sides thereof. In the adhesive label 30, the first surface layer 12 of the laminated film 10 is arranged on the adhesive layer 31 side, and the second surface layer 13 is arranged on the printed layer 40 side.

<Adhesive layer>
Examples of the adhesive used for the adhesive layer include rubber-based adhesives, acrylic-based adhesives, and silicone-based adhesives.

Examples of rubber-based pressure-sensitive adhesives include polyisobutylene rubber, butyl rubber, mixtures thereof, and rubber-based pressure-sensitive adhesives obtained by blending these with a tackifier. Examples of the tackifier include abietic acid rosin ester, terpene-phenol copolymer, terpene-indene copolymer, and the like.
Examples of acrylic adhesives include compounds having a glass transition point of −20° C. or lower, such as 2-ethylhexyl acrylate/n-butyl acrylate copolymer or 2-ethylhexyl acrylate/ethyl acrylate/methyl methacrylate copolymer. is mentioned.
Examples of the silicone-based pressure-sensitive adhesive include an addition-curable pressure-sensitive adhesive that uses a platinum compound or the like as a catalyst, and a peroxide-curable pressure-sensitive adhesive that is cured with benzoyl peroxide or the like.
The form of the adhesive is not particularly limited, and various forms of adhesive such as solution type, emulsion type, or hot melt type can be used.

The pressure-sensitive adhesive layer may be formed by directly applying the pressure-sensitive adhesive to the surface of the coated film, or may be formed by applying the pressure-sensitive adhesive to the surface of the release sheet described later to form the pressure-sensitive adhesive layer, and then coating it. You may make it stick together on the surface of a film.
Apparatuses for applying the adhesive include bar coaters, blade coaters, comma coaters, die coaters, air knife coaters, gravure coaters, lip coaters, reverse coaters, roll coaters, spray coaters, and the like. The pressure-sensitive adhesive layer is formed by smoothing and drying the pressure-sensitive adhesive coating film applied by these coating devices, if necessary.

<Coating amount>
The coating amount of the adhesive is not particularly limited, but the solid content after drying is preferably 3 to 60 g/m ² , more preferably 10 to 40 g/m ² .

<Release sheet>
A release sheet may be provided on the pressure-sensitive adhesive layer as necessary for the purpose of protecting the surface of the pressure-sensitive adhesive layer.
As the release sheet, for example, high-quality paper, kraft paper, calendered, resin-coated or film-laminated sheets, glassine paper, coated paper, or silicone-treated resin films can be used. be able to. Among these, it is preferable to use a sheet having a silicone-treated surface on the surface in contact with the pressure-sensitive adhesive layer, because it has good releasability from the pressure-sensitive adhesive layer.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Descriptions of "parts", "%", etc. in the examples are based on mass unless otherwise specified.

Table 1 is a list of materials used in Examples and Comparative Examples.

Table 2 is a list of compounding ratios of materials in each resin composition.

Table 3 is a list of compounding ratios of materials used in the coating solution for forming the coat layer.

(Preparation of coating liquid (a) for forming coat layer)
As shown in Table 3, as the coating agent, 50 parts by mass (in terms of solid content) of an acrylic acid ester resin (trade name: Saftomer ST3200, manufactured by Mitsubishi Chemical Corporation) and a polyethyleneimine resin (trade name: Saftomer AC72, Mitsubishi (manufactured by Chemical Co., Ltd.) was prepared as a coating liquid (a) for forming a coat layer.

(Preparation of coating liquid (b) for forming coat layer)
As a coating agent, 10 parts by mass (in terms of solid content) of acrylic acid ester resin (trade name: Saftomer ST3200), 10 parts by mass (in terms of solid content) of polyethyleneimine resin (trade name: Saftomer AC72), and ethylene methacrylic An aqueous solution containing 80 parts by mass (in terms of solid content) of an acid copolymer (trade name: Aquatex AC3100, manufactured by Japan Coating Resin Co., Ltd.) was prepared as a coating liquid (b) for forming a coat layer.

(Preparation of coating liquid (c) for forming coat layer)
As a coating agent, an aqueous solution containing 100 parts by mass (in terms of solid content) of a polyethyleneimine resin (trade name: Saftomer AC72) was prepared as a coating liquid (c) for forming a coat layer.

(Example 1)
<Production of laminated film>
41 parts by mass of a propylene homopolymer (trade name: HC101BF, manufactured by Borealis, MFR: 3.2 g/10 min) produced using vegetable oil as a raw material, and a petroleum-derived propylene homopolymer (trade name: Novatec PP FY6, Japan Polypropylene Corporation, MFR: 2.4 g/10 min (JIS K7210), Density: 0.90 g/cm ³ ) 41 parts by mass, and petroleum-derived propylene homopolymer (trade name: Novatec PP MA3, Japan Polypropylene Corporation) 14 parts by mass of MFR: 11 g/10 min (JIS K7210), density: 0.90 g/cm ³ , and petroleum-derived maleic acid-modified polypropylene (trade name: Yumex 1001, manufactured by Sanyo Chemical Industries, Ltd., acid value: 26 mg KOH /g, density: 0.90 g/cm ³ ) 1 part by mass, and petroleum-derived high-density polyethylene (trade name: Novatec HD HJ580N, manufactured by Japan Polyethylene Co., Ltd., MFR: 12 g/10 min (JIS K7210), density: 0 .96 g/cm ³ ) 13 parts by mass, and 20 parts by mass of heavy calcium carbonate particles (trade name: Softon 1800, manufactured by Bihoku Funka Kogyo Co., Ltd., average particle size: 1.25 μm, density: 2.72 g/cm ³ ). and were mixed to prepare a resin composition B. This was melt-kneaded by an extruder with a cylinder temperature set to 230° C., extruded into strands, cooled and cut to obtain resin composition B pellets.

Separately, 9 parts by mass of the biomass-derived propylene homopolymer (trade name: HC101BF), 85 parts by mass of the petroleum-derived propylene homopolymer (trade name: Novatec PP FY6), and a petroleum-derived propylene homopolymer 16 parts by mass of coalescence (trade name: Novatec PP MA3), 1 part by mass of petroleum-derived maleic acid-modified polypropylene (trade name: Umex 1001), and 13 parts by mass of petroleum-derived high-density polyethylene (trade name: Novatec HD HJ580N) and 6 parts by mass of heavy calcium carbonate particles (trade name: Softon 1800) to prepare a resin composition A. This was melt-kneaded by an extruder with a cylinder temperature set to 230° C., extruded into strands, cooled and cut to obtain resin composition A pellets.

In addition, 10 parts by mass of a propylene homopolymer (trade name: HE125MO, manufactured by Borealis, MFR: 10 g/10 min) produced using vegetable oil as a raw material, and the petroleum-derived propylene homopolymer (trade name: Novatec PP FY6 ) 20 parts by mass, 30 parts by mass of petroleum-derived propylene homopolymer (trade name: Novatec PP MA3), 1 part by mass of petroleum-derived maleic acid-modified polypropylene (trade name: Umex 1001), and petroleum-derived high-density A resin composition C was prepared by mixing 13 parts by mass of polyethylene (trade name: Novatec HD HJ580N) and 58 parts by mass of heavy calcium carbonate particles (trade name: Softon 1800). This was melt-kneaded by an extruder with a cylinder temperature set to 230° C., extruded into strands, cooled and cut to obtain resin composition C pellets.

After the resin composition B was melt-kneaded by an extruder set at 250° C., it was supplied to an extrusion die set at 250° C. and extruded into a sheet. The extruded sheet was cooled to 60° C. by a cooling device to obtain a non-stretched sheet. This unstretched sheet was heated to 150° C. and stretched 4.8 times in the machine direction (MD direction) by utilizing the peripheral speed difference of the roll group to form a sheet of the substrate layer.

Next, the resin compositions A and C were melt-kneaded by two extruders set at 250° C., and then melt-extruded onto both sides of the substrate layer sheet. As a result, the first surface layer made of the resin composition A is laminated on one side of the substrate layer made of the resin composition B, and the second surface layer made of the resin composition C is laminated on the other side 3. A layered sheet was obtained.

The three-layer sheet was cooled to 60°C by a cooling device, reheated to 150°C, stretched 9 times in the sheet width direction (TD direction) using a tenter, and annealed at 165°C. After cooling to 60° C. again, the lugs were slit to obtain a laminated film of Example 1. The laminated film of Example 1 has a three-layer structure (uniaxially stretched/biaxially stretched/uniaxially stretched), the total thickness is 80 μm, and the thickness of each layer of resin compositions A/B/C is 18 μm/36 μm/ It was 26 μm.

<Manufacture of coated film>
Both surfaces of the laminated film of Example 1 were subjected to corona discharge treatment under conditions of 30 W·min/m ² . Next, the coating liquid (a) for forming a coat layer was applied by a roll coater so that the thickness after drying was 0.03 μm. The coating film was dried in an oven at 60° C. to form a coating layer to obtain a coating film.

(Examples 2 to 5 and 7)
Pellets of resin compositions D to G were prepared in the same manner as for resin composition A, except that the amount of each material in resin composition A was changed as shown in Table 2.
Also, a biomass-derived propylene homopolymer (MFR: about 11 g/10 min (JIS K7210)) obtained by polymerizing propylene produced using sugarcane as a raw material according to the usual method using a Ziegler-Natta catalyst 9 parts by mass, 73 parts by mass of petroleum-derived propylene homopolymer (trade name: Novatec PP FY6), 14 parts by mass of petroleum-derived propylene homopolymer (trade name: Novatec PP MA3), and petroleum-derived maleic acid modification 1 part by mass of polypropylene (trade name: Yumex 1001), 13 parts by mass of petroleum-derived high-density polyethylene (trade name: Novatec HD HJ580N), and 20 parts by mass of heavy calcium carbonate particles (trade name: Softon 1800) are mixed. Then, resin composition J was prepared. Next, pellets of resin composition J were produced in the same manner as resin composition A.

Laminated films and coated films of Examples 2 to 5 and 7 were prepared in the same manner as in Example 1, except that the resin composition A was changed to resin compositions D to G and J to form the first surface layer. manufactured. The layer structures of the laminated films of Examples 2 to 5 and 7 are shown in Table 4.

(Example 6)
Pellets of resin composition H were prepared in the same manner as resin composition A except that the amount of each material of resin composition A was changed as shown in Table 2.

In addition, 32 parts by mass of the biomass-derived propylene homopolymer (trade name: HC101BF), 65 parts by mass of the biomass-derived propylene homopolymer (trade name: HE125MO), and petroleum-derived maleic acid-modified polypropylene (trade name: Umex 1001) 1 part by mass, petroleum-derived high-density polyethylene (trade name: Novatec HD HJ580N) 3 parts by mass, and heavy calcium carbonate particles (trade name: Softon 1800) 29 parts by mass were mixed to obtain a resin composition. Item I was prepared. This was melt-kneaded in an extruder with a cylinder temperature of 230° C., extruded into strands, cooled and cut to obtain resin composition I pellets.

The procedure of Example 1 was repeated except that the resin composition A was changed to the resin composition H to form the first surface layer, and the resin composition C was changed to the resin composition I to form the second surface layer. A laminated film and a coated film of Example 6 were produced. The layer structure of the laminated film of Example 6 is shown in Table 4.

(Example 8)
<Production of laminated film>
Pellets of each resin composition K, N and L were prepared in the same manner as for resin composition C except that the amount of each material of resin composition C was changed as shown in Table 2.

Pellets of resin compositions K, N and L were melt-kneaded by three extruders set at 250°C. These were supplied to one coextrusion die, laminated to form a three-layer structure of K/N/L inside the die, and extruded into a sheet from the die.

The extruded sheet was cooled by cooling rolls to obtain an unstretched sheet. After reheating this unstretched sheet to 150° C., it was stretched twice in the sheet flow direction (MD direction) using the speed difference between the rolls to obtain a longitudinally stretched resin film. Then, the longitudinally stretched resin film was cooled to 60°C, reheated to 150°C, stretched twice in the sheet width direction (TD direction) using a tenter, and annealed at 165°C. Thereafter, after cooling to 60° C. again, the tabs were slit to obtain a laminated film of Example 8. The laminated film of Example 8 has a three-layer structure (biaxially stretched/biaxially stretched/biaxially stretched), the total thickness is 80 μm, and the thickness of each layer of the resin composition K/N/L is 18 μm/36 μm/ It was 26 μm.

<Manufacture of coated film>
A coat layer was formed on the laminated film in the same manner as in Example 1 to produce a coated film of Example 8.

(Example 9)
<Production of laminated film>
Pellets of the above resin compositions A, B and C were melt-kneaded by three extruders set at 250°C. These were supplied to one co-extrusion die, laminated to form a three-layer structure of A/B/C inside the die, and extruded into a sheet from the die.

The extruded sheet was cooled by cooling rolls to obtain an unstretched sheet. After reheating this unstretched sheet to 150° C., it was stretched 4.8 times in the sheet flow direction (MD direction) using the speed difference between the rolls to obtain a longitudinally stretched film. Then, the longitudinally stretched film was cooled to 60°C, reheated to 150°C, stretched 9 times in the sheet width direction (TD direction) using a tenter, and annealed at 165°C. After cooling to 60° C. again, the lugs were slit to obtain a laminated film of Example 9. The laminated film of Example 9 has a three-layer structure (biaxially stretched/biaxially stretched/biaxially stretched), the total thickness is 80 μm, and the thickness of each layer of the resin composition A/B/C is 18 μm/36 μm/ It was 26 μm.

<Manufacture of coated film>
A coat layer was formed on the laminated film in the same manner as in Example 1 to produce a coated film of Example 9.

(Examples 10 and 11)
Each of Examples 10 and 10 in the same manner as in Example 2 except that the coating solution for forming the coat layer (a) was changed to the coating solution for forming the coat layer (b) and (c) to form the coat layer. Eleven coated films were produced.

(Example 12)
82 parts by mass of the biomass-derived propylene homopolymer (trade name: HC101BF), 14 parts by mass of the biomass-derived propylene homopolymer (trade name: HE125MO), and petroleum-derived maleic acid-modified polypropylene (trade name: Yumex 1001) ) 1 part by mass, biomass-derived high-density polyethylene (trade name: HDPE SHC7260, manufactured by Braskem, MFR; 7.2 g / 10 min, density; 0.959 g / cm ³ ) 6.5 parts by mass, petroleum-derived 6.5 parts by mass of high-density polyethylene (trade name: Novatec HD HJ580N) and 20 parts by mass of heavy calcium carbonate particles (trade name: Softon 1800) were mixed to prepare a resin composition M. This was melt-kneaded by an extruder with a cylinder temperature set to 230° C., extruded into strands, cooled and cut to obtain resin composition M pellets.

In the same manner as in Example 2, except that the resin composition B was changed to the resin composition M to form the base layer, and the resin composition C was changed to the resin composition I to form the second surface layer. A laminated film and coated film of Example 12 were produced.

(Example 13)
A laminated film and a coated film of Example 13 were produced in the same manner as in Example 1, except that the resin composition C was changed to the resin composition A to form the second surface layer.

(Example 14)
The procedure of Example 1 was repeated except that the resin composition A was changed to the resin composition E to form the first surface layer, and the resin composition C was changed to the resin composition N to form the second surface layer. A laminated film and a coated film of Example 14 were produced.

(Comparative example 1)
A laminated film and a coated film of Comparative Example 1 were produced in the same manner as in Example 1, except that the resin composition A was changed to the resin composition C to form the first surface layer.

(Comparative example 2)
After melt-kneading the resin composition M with an extruder set at 250° C., it was supplied to an extrusion die set at 250° C. and extruded into a sheet. The extruded sheet was cooled to 60° C. by a cooling device to obtain a non-stretched sheet. This unstretched sheet was heated to 150° C. and stretched 4.8 times in the machine direction (MD direction) by utilizing the peripheral speed difference of the roll group to form a sheet of the substrate layer.

The base layer sheet was cooled to 60°C by a cooling device, reheated to 150°C, stretched 9 times in the sheet width direction (TD direction) using a tenter, and annealed at 165°C. After cooling to 60° C. again, the tab was slit to obtain a laminated film of Comparative Example 2. The laminated film of Comparative Example 2 was a biaxially stretched film having a single layer structure and a total thickness of 80 µm.

(Measurement of physical properties)
The physical properties of the laminated films and coated films of Examples and Comparative Examples were measured as follows.

<Overall thickness>
The total thickness (μm) of the laminated film is measured using a constant pressure thickness measuring instrument (equipment name: PG-01J, manufactured by Teclock) based on JIS K7130: 1999 "Plastics - Films and sheets - Thickness measurement method". measured by

<Thickness of each layer>
The thickness (μm) of each layer in the multilayer structure was measured as follows.
The laminated film was cooled with liquid nitrogen to a temperature of -60°C or less, and a razor blade (trade name: Proline blade, manufactured by Sic Japan) was applied at right angles to the sample placed on the glass plate and cut. , a sample for cross-sectional measurement was prepared. The cross section of the obtained sample was observed with a scanning electron microscope (equipment name: JSM-6490, manufactured by JEOL Ltd.), and the boundary line of each layer was determined from the appearance that differs depending on the composition, and the thickness of each layer in the laminated film. I asked for the ratio. The total thickness measured above was multiplied by the thickness ratio of each layer to obtain the thickness of each layer.

<Porosity>
Cut out an arbitrary part of the laminated film to be measured, embed it in epoxy resin and solidify it, cut it perpendicular to the surface direction of the laminated film to be measured using a microtome, and observe the cut surface It was affixed to the observation sample stand so as to be a plane. Gold or gold-palladium or the like is vapor-deposited on the observation surface, and the cut surface of the laminated film is observed at an arbitrary magnification that is easy to observe with a scanning electron microscope (for example, a magnification of 500 to 3000 times). Regions were captured as image data. The image data was image-processed by an image analyzer to determine the area ratio (%) of the void portions in a given region of each layer of the laminated film. The average value of the area ratios (%) determined at 10 or more arbitrary locations was taken as the porosity (%) of each layer.

(evaluation)
The laminated films and coated films of Examples and Comparative Examples were evaluated as follows.

<Biomass degree>
The ratio (%) of the total mass of biomass-derived polypropylene and biomass-derived polyethylene to the total mass of all raw materials constituting the laminated film was calculated as the degree of biomass (%).

<Whiteness>
The whiteness (%) of the laminated film was measured using a color meter according to the method specified in JIS L1015:1999. As a color meter, a touch panel type color computer SM-T manufactured by Suga Test Instruments Co., Ltd. was used. The measured whiteness was evaluated according to the following criteria. The higher the whiteness, the clearer the printed content. If the whiteness is 95% or more, a clear display equivalent to pulp paper is possible.
O: Whiteness is 95% or more.
x: Whiteness is less than 95%.

<Water scratch resistance of UV ink>
The coated film was cut into an A2 size (420 mm×594 mm), and a design was offset-printed on the coat layer on the second surface layer side. For printing, an offset printing machine (trade name: SM102, manufactured by Heidelberg) and UV curable sheet-fed process ink (trade name: UV BC161 (black, indigo, red, yellow), manufactured by T&K TOKA) were used. The pattern was printed in four colors of black, indigo, red and yellow, and the density of each color was 100%. Specifically, UV offset four-color printing was performed at a speed of 6000 sheets/hour under an environment of 23° C. temperature and 50% relative humidity, under two metal halide lamps (100 W/cm, manufactured by Eyegraphic Co., Ltd.). to dry the ink on the printed surface. 1000 sheets were continuously printed to obtain an offset printed matter.

The obtained offset printed material was punched out into a size of 70 mm×110 mm, which was immersed in deionized water at 23° C. for 24 hours, and then the printed material was taken out from the water. The printed material taken out was set in a Gakushin-type dyeing friction fastness tester (trade name: Friction tester II type, manufactured by Suga Test Instruments Co., Ltd.) to conduct a friction test. In the friction test, the printed surface was rubbed 100 times with a white cotton cloth (Kinfu No. 3) under a load of 215 g in accordance with JIS L0849:2004 (method for testing color fastness to rubbing).

The ink portion before and after the test was subjected to image processing using an image analyzer (type Luzex IID, manufactured by Nireco), and the residual ratio of the area of the ink portion was calculated and judged according to the following criteria.
◎: 95% or more of the ink remains on the recording paper, excellent level ○: 90% or more, less than 95% of the ink remains on the recording paper, good level △: 70% or more, 90% of the ink Less than practicable level remains on the recording paper ×: Less than 70% of the ink remains on the recording paper, impractical level

<Adhesive residual rate>
A pressure-sensitive adhesive layer was formed on the coated film in the following manner to produce a pressure-sensitive adhesive label.
A silicone-treated glassine paper (G7B, manufactured by Oji Tac Co., Ltd.) was used as a release sheet. An adhesive was applied to the silicone-treated surface of the glassine paper with a comma coater so that the basis weight after drying was 25 g/m ² and dried to form an adhesive layer. The adhesive is a solvent-based acrylic adhesive (Olibain BPS1109, manufactured by Toyochem Co., Ltd.), an isocyanate cross-linking agent (Oribain BHS8515, manufactured by Toyochem Co., Ltd.), and toluene mixed in a ratio of 100:3:45. prepared. A coat film was laminated on the pressure-sensitive adhesive layer so that the coat layer side on the first surface layer side was in contact with the pressure-sensitive adhesive layer, and pressure-bonded with a pressure bonding roll to form a pressure-sensitive adhesive layer on the coat layer.

The release sheet of the adhesive label was peeled off, and the surface on the adhesive layer side was attached to a transparent and highly smooth glass plate, and rubbed three times with a finger to sufficiently adhere the label. This glass plate was heat-treated for 24 hours in an environment at a temperature of 40° C., and then immersed in water at 23° C. for 24 hours. After 5 minutes from removing the glass plate from the water and lightly wiping off water with a waste cloth, the adhesive label was manually peeled off from the glass plate in a direction of 180 degrees at a speed of 300 m/min. The haze of the portion of the glass plate after peeling off the adhesive label was measured according to JIS K7136:2000. A haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., model name: NDH2000) was used for the measurement.

From the difference between the haze measured after peeling and the haze of the glass plate before sticking the adhesive label, the adhesive residual rate was determined according to the following criteria. It can be evaluated that the smaller the haze difference, the lower the residual rate of the adhesive.
◎: Haze difference is less than 3%, excellent level ○: Haze difference is 3% or more and less than 5%, good level △: Haze difference is 5% or more and less than 10%, practical level × : Haze difference is 10% or more, impractical level

Table 4 shows the evaluation results.

As shown in Table 4, Examples 1 to 14 have a biomass degree of 10 or more, and thus have a low environmental load. In addition, Examples 1 to 14, in which the porosity of the first surface layer is 40% or less, have a low adhesive residue rate, and can provide adhesive films in which the adhesive hardly remains on the adherend. On the other hand, in Comparative Example 1, in which the porosity of the first surface layer exceeds 40%, the adhesive tends to remain even after the coat layer is provided. Comparative Example 2, which does not have the first surface layer, has a high degree of biomass, but a high residual rate of the adhesive.

Also, when comparing Examples 1 to 9 with Examples 10 or 11, it can be seen that the adhesive remaining on the adherend can be more effectively reduced by including the acrylic acid ester resin in the coat layer. Adhesion to UV ink is also improved by the coating layer, and water scratch resistance is excellent.

10 Laminated film 11 Base layer 12 First surface layer 13 Second surface layer 20 Coat film 21 Coat layer 30 Adhesive label 31 Adhesive layer 40 Print layer

Claims (9)

A laminated film comprising a substrate layer and a first surface layer on one surface of the substrate layer,
including a porous stretched film containing an olefinic resin and an inorganic filler;
The olefin-based resin contains a propylene-based resin,
The propylene-based resin includes a biomass-derived propylene-based resin,
A laminated film, wherein the first surface layer has a porosity of 40% or less. The laminated film according to claim 1, wherein the propylene-based resin further contains a petroleum-derived propylene-based resin. The laminated film according to claim 1 or 2, wherein the olefin-based resin further contains an ethylene-based resin. The laminated film according to claim 3, wherein the ethylene-based resin contains a biomass-derived ethylene-based resin. The laminated film according to claim 3 or 4, wherein the ethylene-based resin contains a petroleum-derived ethylene-based resin. The laminated film according to any one of claims 1 to 5, wherein the first surface layer has a porosity of 0.1 to 30%. comprising a second surface layer on the other side of the base layer;
The laminated film according to any one of claims 1 to 6, wherein the second surface layer has a porosity of 30 to 55%. A laminated film according to any one of claims 1 to 7,
a coat layer on at least one surface of the laminated film,
A coat film, wherein the coat layer contains a (meth)acrylic ester-based resin. A laminated film according to any one of claims 1 to 7,
and an adhesive layer provided on one surface of the laminated film.

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