WO2022054589A1 - Mat-style laminated film, laminate formed by laminating said mat-style laminated film and plastic substrate, and packaging material using same - Google Patents

Abstract

Provided is a mat-style laminated film in which a surface resin layer (A) containing high-density polyethylene (a1) derived from a plant having a melt flow rate of 1 g/10 min or less and a propylene-based resin (a2) having a melt flow rate of 0.5 g/10 min to 30 g/10 min, and a resin layer (B) containing a polyolefin-based resin (b1) are laminated, the mat-style laminated film containing, as the propylene-based resin (a2), a propylene homopolymer (a2-1) and a propylene-α-olefin block copolymer (a2-2).

Description

A matte-like laminated film, a laminated body made by laminating the matte-like laminated film and a plastic base material, and a packaging material using these.

The present invention relates to a packaging material for packaging foods, miscellaneous goods, magazines, etc., and is specifically used by printing on a single film or surface, or laminating Japanese paper or other films. The present invention relates to a matte-like (matte) laminated film and a packaging material made of the film.

In recent years, various wrapping materials for costumes have been used in various packagings for foods such as bread and confectionery, miscellaneous goods, and magazines. In particular, the need for a matte film having a matte surface is increasing. The matte-like film has a texture similar to that of Japanese paper as compared with a general transparent film, and thus brings out a high-class feeling of the contents. As such a matte film, for example, in order to obtain a sufficient matte feeling, a multilayer film of a resin layer in which a propylene-based material and high-density polyethylene are mixed and a resin layer containing a propylene-based resin (Patent Documents). 1) etc. are disclosed.
On the other hand, major domestic distributors and food manufacturers are aiming to respond to COP21 and to secure a sustainable production and consumption form, which is one of the Sustainable Development Goals (SDGs). As an initiative, we are actively promoting packages to reduce environmental impact. Conventional efforts for the environmental load reduction package have been to promote the "3Rs" (volume reduction, reuse, recycling), but in recent years, fossils such as petroleum have been promoted from the viewpoint of saving petroleum resources. The adoption of resins using plant-derived components as the main raw material (hereinafter referred to as "plant-derived resins") is increasing in place of resins containing fuel-derived components as the main component.
As a plant-derived resin, there is a biodegradable resin typified by polylactic acid (PLA), but the resin has a problem in generalization in terms of cost and processability. On the other hand, as a general-purpose resin, polyethylene derived from plants, which is a renewable resource derived from sugar cane, has shown increasing worldwide demand, and the cost has become general-purpose due to an increase in production volume. As a package for reducing environmental load, such general-purpose plant-derived resins are often used for sanitary and food packaging containers, miscellaneous goods, and plastic shopping bags, but recently, they have been applied to food packaging films. Adoption is expanding.
In addition, since the needs for reducing the environmental load are increasing, it is desired to increase the ratio (biomass degree) of the plant-derived resin in the film (biomass film) using the plant-derived resin. There is.

Japanese Unexamined Patent Publication No. 2016-68417

Although plant-derived resins are highly environmentally friendly, they often exhibit different properties from fossil fuel-derived resins. Therefore, when a film is produced by replacing the fossil-derived resin with a plant-derived resin, various physical properties of the film such as impact resistance, rigidity, film forming property, glossiness, and cloudiness may be deteriorated. In particular, when the proportion of the plant-derived resin is increased, the influence on the physical characteristics of the film becomes large. However, the effect of using a plant-derived resin in the matte laminated film has not been investigated so far.
As a result of examining various physical properties by using a plant-derived resin in a matte-like film, the present inventors have found that there is a problem that the film-forming property, which is one of the most basic performances in film production, is deteriorated. rice field.
The subject of the present invention has been made in view of the above problems, has excellent film forming property even when a plant-derived resin is used, and has excellent packaging suitability and mechanical properties required for packaging materials. It is an object of the present invention to provide a laminated film capable of obtaining a sufficient matte feeling without impairing the strength, a laminated body formed by laminating the film and a plastic base material, and a packaging material made of the laminated film or the laminated body thereof.

The present invention comprises a plant-derived high-density polyethylene (a1) having a melt florate of 1 g / 10 minutes or less and a propylene resin having a melt florate of 0.5 g / 10 minutes or more and 30 g / 10 minutes or less (a1). A matte laminated film in which a surface resin layer (A) containing a2) and a resin layer (B) containing a polyolefin resin (b1) are laminated, as the propylene resin (a2). A matte laminated film characterized by containing a propylene homopolymer (a2-1) and a propylene-ethylene block copolymer (a2-2), and the matte laminated film and a plastic base material are laminated. The subject of the present invention is solved by the laminated body and the packaging material made of these laminated films or laminated bodies.

The laminated film of the present invention can reduce the environmental load by containing a plant-derived resin, has excellent film-forming properties, and has the packaging suitability and mechanical strength required for packaging materials. It develops a sufficient matte feeling without damaging it. The laminated film of the present invention can be used alone, and can be adhered to or fused to other plastic substrates or plastic containers, so that it is excellent in suitability as a packaging material. Therefore, it can be suitably used for foods used to bring out a sense of quality, especially as a bread packaging bag that is stored and transferred at room temperature.

The laminated film in the present invention is a matte laminated film having at least a surface resin layer (A) and a resin layer (B).
The surface resin layer (A) in the laminated film of the present invention contains a plant-derived high-density polyethylene (a1) having a melt retard rate of 1 g / 10 minutes or less and a melt retard rate of 0.5 g / 10 minutes or more. It contains 30 g / 10 minutes or less of a propylene-based resin (a2).

The plant-derived high-density polyethylene (a1) is a polyethylene-based resin produced from plant-derived ethylene using sugar cane, corn, beat or the like as a starting material. Examples of the biomass polyethylene (a1) include linear high-density polyethylene (LHDPE) and high-density polyethylene (HDPE), which may be used alone or in combination. Among these, high density polyethylene (HDPE) is particularly preferable.
The plant-derived high-density polyethylene (a1) of the present invention requires that the melt flow rate (temperature 190 ° C., load 2.16 kg) be 1 g / 10 minutes or less. If the melt flow rate exceeds 1 g / 10 minutes, it becomes difficult to obtain a matte film having a texture similar to that of Japanese paper. A particularly preferable melt flow rate is in the range of 0.05 to 0.8 g / 10 minutes.

Further, the density of the plant-derived high-density polyethylene (a1) is in the range of 0.935 to 0.970 g / cm ² , but the matte feeling, mechanical strength, film uniformity, etc. of the obtained laminated film are obtained. From the viewpoint of the above, it is more preferably in the range of 0.940 to 0.965 g / cm ² .

The propylene-based resin (a2) contains a propylene homopolymer (a2-1) and a propylene-ethylene block copolymer (a2-2). By containing two components of the propylene homopolymer (a2-1) and the propylene-ethylene block copolymer (a2-2) as the propylene resin, the film forming property can be improved and the matte feeling can be obtained. , The surface roughness can be easily adjusted.
As the propylene-based resin (a2), resins other than the propylene homopolymer (a2-1) and the propylene-ethylene block copolymer (a2-2), for example, a propylene-ethylene random copolymer and a propylene-α-olefin copolymer weight. It may contain a coalescence (propylene-1-butene random copolymer, propylene-1-hexene random copolymer, etc.), propylene-ethylene-1-butene random copolymer, and metallocene-catalyzed polypropylene.

The propylene-based resin (a2) of the present invention is essential to have an MFR (temperature 230 ° C., load 2.16 kg) of 0.5 g / 10 minutes or more and 30 g / 10 minutes or less. From the viewpoint of less shrinkage of the film during bag making and further improving the film forming property of the film, it is preferably 4 g / 10 minutes or more and 20 g / 10 minutes or less, and 5 g / 10 minutes or more and 15 g / 10 minutes or less. It is more preferable to have.
The propylene-based resin (a2) of the present invention preferably has a melting point of 120 to 172 ° C, preferably 125 to 170 ° C. When the MFR and the melting point are in this range, the shrinkage of the film during bag making can be further reduced, and the film forming property of the film is further improved.

In the surface resin layer (A), the content of the plant-derived high-density polyethylene (a1) is preferably 50% by mass or more, and preferably 55% by mass or more.

As for the ratio of the plant-derived high-density polyethylene (a1) and the propylene-based resin (a2), the high-density polyethylene (a1) is used in order to give the obtained film a sufficient matte feeling (high cloudiness and low gloss). ) And the propylene-based resin (a2) are preferably in the range of 60/40 to 40/60 in mass ratio (a1) / (a2). When the usage ratio of the plant-derived high-density polyethylene (a1) is lower than this, it is difficult to obtain the desired matte feeling, while when the usage ratio is higher than this, the obtained film is mechanical. The strength, especially the impact strength, is insufficient, and it is difficult to obtain a practical level packaging bag.
Further, the mass ratio (a2-1) / (a2-2) of the propylene homopolymer (a2-1) and the propylene-ethylene block copolymer (a2-2) is in the range of 45/55 to 65/35. It is preferable to have.

The total content of the plant-derived high-density polyethylene (a1) and the propylene-based resin (a2) in the surface resin layer (A) is preferably 80% by mass or more in the surface resin layer (A). , 85% by mass or more, more preferably 90% by mass or more. Within this range, it becomes easy to obtain a film having suitable mechanical strength. More preferably, the total content of the plant-derived high-density polyethylene (a1), the propylene homopolymer (a2-1), and the propylene-ethylene block copolymer (a2-2) is the surface resin layer. It is more preferably 80% by mass or more, 85% by mass or more, and 90% by mass or more in (A).

The surface resin layer (A) may contain components other than the plant-derived high-density polyethylene (a1) and the propylene-based resin (a2) as long as the effects of the present invention are not impaired. Examples of the other components include polystyrene-based resins, polyurethane-based resins, polyester-based resins, and polyamide-based resins. Further, an ethylene resin derived from fossil fuel may be used in combination with an ethylene resin derived from a plant.

Further, in the laminated film of the present invention, the surface roughness (Ra) of the surface resin layer (A) based on JIS B-0601 is preferably 0.5 to 2.0. With the surface roughness in this range, a suitable matte-like film having the texture of Japanese paper can be obtained, so that the designability can be improved.

In order to adjust the range of the surface roughness (Ra), the mass ratio of the high-density polyethylene (a1) and the propylene-based resin (a2) is set to 60 / (a2) as described above. It may be used in a ratio of 40 to 40/60 and does not require any particular adjustment.

The difference in MFR between the plant-derived high-density polyethylene (a1) and the propylene-based resin (a2) is preferably 5 g / 10 minutes or more, and more preferably 6 g / 10 minutes or more. Within this range, it becomes easy to obtain a suitable matte resin layer.

The laminated film of the present invention is formed by laminating the above-mentioned specific surface resin layer (A) on a resin layer (B) containing a polyolefin resin (b1). By forming a film having such a multi-layer structure, it has a matte feeling even when used alone, and it is possible to develop strength and the like for use in packaging bags.

As the polyolefin resin (b1), various polyolefin resins used for packaging films can be used, and for example, a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, and a propylene-α. -Olefin copolymer, propylene-based resin such as (propylene-1-butene random copolymer, propylene-1-hexene random copolymer, etc.), propylene-ethylene-1-butene random copolymer, metallocene-catalyzed polypropylene, etc. (B1-2), ultra-low density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE) and other polyethylene resins, ethylene-vinyl acetate copolymer (EVA), ethylene-methylmetha. Acrylate copolymer (EMMA), ethylene-ethylacryllate copolymer (EEA), ethylene-methylacrelate (EMA) copolymer, ethylene-ethylacryllate-maleic anhydride copolymer (E-) EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) and other ethylene-based copolymers, as well as ethylene-acrylic acid copolymer ionoma-, ethylene-methacryl. An acid copolymer ionoma or the like can be used. Of these, it is preferable to use a propylene-based resin because it is easy to improve the adhesion to the surface resin layer (A). As described above, by using the same type of resin for the surface resin layer (A) and the resin layer (B), the interlayer strength of the laminated film can be enhanced. Particularly preferably, a propylene-ethylene copolymer can be used.
Further, in order to increase the proportion of the plant-derived biomass resin, it is preferable to use a plant-derived resin as the polyolefin-based resin (b1). As the plant-derived resin, since it is easy to improve the adhesion to the surface resin layer (A), the same resin as the plant-derived high-density polyethylene (a1) used in the surface resin layer (A) or an ethylene-based resin of the same type is used. It is preferable to use a resin. Specifically, it is a polyethylene-based resin produced from plant-derived ethylene using sugar cane, corn, beat or the like as a starting material, and is, for example, linear low-density polyethylene (LLDPE) or linear medium-density polyethylene (LMDPE). ), Linear high-density polyethylene (LHDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), etc. May be. Among these, linear low-density polyethylene (b1-1) is particularly preferable. The linear low-density polyelene preferably has a density of 0.925 g / cm ³ or less, and more preferably 0.920 g / cm ³ or less. By setting the density of the linear low-density polyethylene to be used in the above range, it becomes easy to combine suitable fusing strength, high impact resistance, and bag-breaking resistance.

The MFR of the plant-derived polyethylene used for the resin layer (B) is preferably 0.1 to 30 g / 10 minutes, and particularly preferably 0.5 to 20 g / 10 minutes. When it is 1 g / 10 minutes or more, it becomes easy to obtain a suitable film-forming property, and when it is 20 g / 10 minutes or less, it becomes easy to obtain a suitable formability.

The plant-derived high-density polyethylene (a1) used for the surface resin layer (A) and the plant-derived ethylene resin used for the resin layer (B) are made of sugar cane or the like as compared with the petroleum-derived production method. The production method is the same for other plants, except for the production of monomer. The production method is not particularly limited, and can be produced by a known method. For example, a manufacturing method using a Ziegler-Natta catalyst or a metallocene catalyst can be mentioned.

Specifically, it is a catalyst system in which the titanium-containing compound itself or a titanium-containing compound supported on a carrier such as a magnesium compound is used as a main catalyst and an organic aluminum compound is used as an auxiliary catalyst, and propylene alone or desired α such as ethylene is used. -A method of adding an olefin to carry out polymerization can be mentioned. This polymerization may be carried out by any process such as a slurry polymerization method, a solution polymerization method, and a gas phase polymerization method.

Further, a uniform catalyst may be used, and a conventionally used catalyst composed of a vanadium compound and an organic aluminum compound, a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, or the like may be used. A metallocene system consisting of transition metal compounds such as zirconium, titanium, and hafnium having one or two ligands, transition metal compounds whose ligands are geometrically controlled, and cocatalysts such as aluminoxane and ionic compounds. A uniform system such as a catalyst can also be mentioned. As the metallocene catalyst, if necessary, an organic aluminum compound may be used, and in addition to uniform polymerization in the presence of a solvent, any process such as slurry polymerization method or vapor phase polymerization method may be used.

Examples of commercially available products of such plant-derived polyethylene include SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, and SLH0820 manufactured by Braskem.

Among them, the resin layer (B) is directly derived from a plant because it enhances the strength and rigidity of the laminated film, can further emphasize the matte feeling with the surface resin layer (A), and further enhances the degree of biomass of the laminated film. It is preferable to use a chain low-density polyethylene (b1-1) in combination with one or more propylene-based resins (b1-2). The ratio of use at this time is more preferably in the range of plant-derived linear low-density polyethylene (b1-1) / propylene-based resin (b1-2) = 5/95 to 30/70.

In the resin layer (B), the content of the plant-derived linear low-density polyethylene (b1-1) is preferably 10% by mass or more, preferably 15% by mass or more, from the viewpoint of high impact resistance and bag breaking resistance. More preferably, it is by mass.

The total content of the polyolefin resin (b1) in the resin layer (B) is preferably 80% by mass or more, more preferably 85% by mass or more, and 90% by mass. It is more preferably mass% or more. Within this range, it becomes easy to obtain a film having suitable mechanical strength. The total content of the plant-derived linear low-density polyethylene (b1-1) and the propylene-based resin (b1-2) is preferably 80% by mass or more in the resin layer (B). It is more preferably 85% by mass or more, and further preferably 90% by mass or more.

When the laminated film in which the surface resin layer (A) and the resin layer (B) are laminated is used as a packaging bag, the resin layer (B) is excellent in balance between mechanical strength and heat sealability. It is preferable that the seal layer (C) is further provided on the) side.

The seal layer (C) is designed so that the seal strength can be easily obtained at the time of heat sealing between the seal layers (C) of the laminated film or in a container made of other materials. The resin type can be selected depending on the use of the obtained laminated film. In particular, when it is used as a packaging bag and the seal layers (C) are heat-sealed with each other, an appropriate seal strength can be obtained, so that the seal layer (C) contains a propylene-ethylene random copolymer. Is preferable. Further, in order to adjust the seal strength, it is also possible to use an ethylene-α-olefin copolymer in combination.

The matte laminated film of the present invention may have one or two or more other layers in addition to the surface resin layer (A), the resin layer (B) and the seal layer (C). As the other layer, various resin materials used for the packaging film can be used, and it is preferable that the other layer is provided between the resin layer (B) and the seal layer (C).

The total mass of polyethylene contained in the matte laminated film of the present invention is preferably 20% by mass or more, more preferably 23% by mass or more, and 24% by mass or more with respect to the mass of the laminated film. It is more preferable to have. In order to increase the amount of plant-derived components in the mat-like laminated film and increase the degree of biomass, it is preferable that the total mass of the plant-derived polyethylene is 20% by mass or more with respect to the mass of the mat-like laminated film, and the total mass is 23. % Or more, more preferably 24% by mass or more.
Further, the total mass of polyethylene, preferably the total mass of polyethylene derived from plants, should be 24% by mass or more with respect to the total mass of the surface resin layer (A) and the resin layer (B) adjacent to the surface resin layer. Is more preferable, and it is more preferably 27% by mass or more, and further preferably 28% by mass.

Since the laminated film of the present invention has sufficient strength as a film by itself, its total thickness is preferably in the range of 20 to 50 μm, and is particularly used for packaging relatively lightweight contents such as bread. In this case, it is preferably 25 to 40 μm.

Further, in order to give a sufficient matte feeling (high cloudiness and low glossiness) to the laminated film, it is preferable that the surface resin layer (A) is 10 to 40% of the total thickness. The thickness of the resin layer (A) is preferably 2 to 20 μm, more preferably 4 to 16 μm, because it is easy to obtain suitable design.
Further, it is preferable that the resin layer (B) has a total thickness of 30 to 90%. The thickness of the resin layer (B) is preferably 6 to 45 μm, more preferably 10 to 30 μm.
Further, when the seal layer (C) is provided, it is preferable that the seal layer (C) has a total thickness of 10 to 25%. The thickness of the seal layer (C) is preferably 2 to 12.5 μm, more preferably 3 to 10 μm.

The degree of fogging of the laminated film of the present invention is preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more in order to obtain a sufficient matte feeling.

The glossiness of the laminated film of the present invention is preferably 20% or less, more preferably 10% or less, and 5% or less in order to suppress the gloss of the surface and give a texture close to that of Japanese paper. Is more preferable.
The rigidity of the laminated film of the present invention is preferably 500 MPa or more, more preferably 600 MPa or more, still more preferably 650 MPa or more, in order to maintain suitable strength when applied as a packaging material. ..
The impact strength of the laminated film of the present invention is preferably 0.15 J (23 ° C.) or higher, and more preferably 0.17 J (23 ° C.) or higher. The impact strength is determined by holding the sample in a constant temperature room adjusted to 23 ° C. for 6 hours and then measuring the impact strength by the film impact method using a spherical impact head having a diameter of 25.4 mm.

Each of the resin layers (A), (B) or (C) may contain an anti-fog agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an anti-blocking agent, if necessary. Ingredients such as a mold release agent, an ultraviolet absorber, and a colorant can be added within a range that does not impair the object of the present invention.

The method for producing the laminated film of the present invention is not particularly limited, but for example, each resin or resin mixture used for the surface resin layer (A), the resin layer (B) and the seal layer (C) is separately used. It is heated and melted by an extruder, laminated in the order of (A) / (B) / (C) in a molten state by a method such as a coextrusion multi-layer die method or a feed block method, and then inflation or T-die. Examples thereof include a coextrusion method in which the film is formed into a film by a chill roll method or the like. This coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a coextruded multilayer film having excellent hygiene and cost performance can be obtained. Further, since the high-density polyethylene (a1) and the propylene-based resin (a2) used in the present invention have a large difference in melting point between them, the appearance of the film may be deteriorated during the coextrusion process. In order to suppress such deterioration, the T-die chill roll method, which can perform melt extrusion at a relatively high temperature, is preferable.

Since the laminated film of the present invention can be obtained as a substantially unstretched multilayer film by the above manufacturing method, secondary molding such as deep drawing by vacuum forming is also possible.

Further, when printing or the like is performed on the surface resin layer (A), it is preferable to apply a surface treatment to the resin layer (A) in order to improve the adhesiveness with the printing ink. When the other film is attached to the surface of the resin layer (B) or the seal layer (C), the resin layer (B) or the seal layer (C) is used in order to improve the adhesion with the adhesive. Is preferably surface-treated. Examples of such surface treatments include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable.

In the packaging bag, the seal layer (C) of the laminated film of the present invention is used as a heat seal layer, and the seal layers (C) are overlapped with each other to form a heat seal or a surface resin layer (A). ) And the seal layer (C) are overlapped and heat-sealed to form a packaging bag with the seal layer (C) as the inside. For example, two laminated films are cut out to the desired size of a packaging bag, and they are stacked to form a bag by heat-sealing three sides, and then one side without heat-sealing. It can be used as a packaging bag by filling it with the contents, heat-sealing it, and sealing it. Furthermore, it is also possible to form a packaging bag by sealing the end of a roll-shaped film in a cylindrical shape with an automatic packaging machine and then sealing the top and bottom.

Further, the laminated film of the present invention and another film can be laminated and used as a composite film. The other film may be provided on the surface resin layer (A) side or on the resin layer (B) or seal layer (C) side, but the resin layer (B) or seal layer (C) may be provided. It is preferable to provide a sealant film on the) side.
At that time, as another film to be used, a film such as LDPE, EVA, or polypropylene having a relatively weak mechanical strength can be used, and it is preferable to use a biaxially stretched polypropylene film (OPP). Further, a lamine in which a film such as LDPE, EVA, polypropylene and a stretched film having relatively good tearability, for example, a biaxially stretched polyethylene terephthalate film (OPET), a biaxially stretched polypropylene film (OPP), etc. are bonded together. -Polyethylene film can also be used.
Further, as a method of laminating a laminated body formed by laminating a laminated film of the present invention and another film, in addition to the above heat seal, for example, dry lamination, wet lamination, non-solvent, etc. Examples thereof include methods such as laminating and extrusion laminating.

Examples of the adhesive used in the dry lamination include a polyether-polyurethane-based adhesive, a polyester-polyurethane-based adhesive, and the like.

As a packaging material using the laminated film of the present invention or a laminated body obtained by laminating the laminated film of the present invention and a plastic base material, a packaging bag used for foods, chemicals, industrial parts, miscellaneous goods, magazines, etc. , Containers, container lids, etc. In particular, since the matte feeling is superior to that of the past, it is possible to provide a packaging material similar to Japanese paper and the like, and it can be suitably used for foods and the like used to bring out a high-class feeling.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. Hereinafter, unless otherwise specified, "part" is based on mass.

Example 1
As the surface layer (A), 20 parts of a propylene homopolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and high-density polyethylene derived from sugar cane (Brackem SGM9450F density: 0.952 g / cm3). , MFR: 0.05 g / 10 min) 55 parts and propylene-ethylene block copolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 min) 25 parts board.
Further, as the resin layer (B), 85 parts of a propylene-ethylene block copolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and a linear low-density polyethylene derived from sugar cane (Brackem). SLH218 Density: 0.916 g / cm3, MFR: 2.3 g / 10 minutes) A mixture consisting of 15 parts was used.
Further, as the seal layer (C), 80 parts of (1) propylene-ethylene random copolymer (density: 0.90 g / cm3, MFR: 5.0 g / 10 minutes) and (2) propylene-. A mixture consisting of 20 parts of an ethylene random copolymer (density: 0.90 g / cm3, MFR: 8.0 g / 10 minutes) was used.
These are each supplied to three extruders and co-extruded so that the average thickness of the surface resin layer (A), the resin layer (B) and the seal layer (C) is 7: 10: 3. A three-layer film having a thickness of 30 μm was formed. Next, the seal layer (C) of the obtained three-layer film was subjected to a corona discharge treatment so that the surface energy was 36 mN / m to obtain a laminated film.

Example 2
As the surface resin layer (A) of Example 1, 27 parts of propylene homopolymer / 55 parts of high-density polyethylene derived from sugar cane / 18 parts of propylene-ethylene block copolymer were replaced with the same thickness as in Example 1. A coextruded multilayer film having three layers of 30 μm was obtained. Next, the surface of the seal layer (C) of the obtained film was subjected to a corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1.

Comparative Example 1
As the surface resin layer (A), 40 parts of a propylene homopolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and high-density polyethylene derived from sugar cane (SGM9450F density of Braskem): 0.952 g / A mixture consisting of 60 parts (cm3, MFR: 0.05 g / 10 minutes) was used.
In addition, as the intermediate layer (B), 85 parts of a propylene-ethylene block copolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and a linear low-density high-density polyethylene derived from sugar cane. (Brackem SLH218 Density: 0.916 g / cm3, MFR: 2.3 g / 10 minutes) A mixture consisting of 15 parts was used.
Further, as the seal layer (C), 80 parts of (1) propylene-ethylene random copolymer (density: 0.90 g / cm3, MFR: 5.0 g / 10 minutes) and (2) propylene-. A mixture consisting of 20 parts of an ethylene random copolymer (density: 0.90 g / cm3, MFR: 8.0 g / 10 minutes) was used.
These are each supplied to three extruders and co-extruded so that the average thickness of the surface resin layer (A), the resin layer (B) and the seal layer (C) is 7: 10: 3. A three-layer film having a thickness of 30 μm was formed. Next, the surface of the seal layer (C) of the obtained film was subjected to a corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1.

Comparative Example 2
As the surface resin layer (A), 40 parts of a propylene homopolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and high-density polyethylene derived from fossil fuel (density: 0.955 g / cm3). , MFR: 0.35 g / 10 min) 60 parts mixture was used.
Further, as the intermediate layer (B), 90 parts of a propylene-ethylene block copolymer (density: 0.90 g / cm3, MFR: 7.0 g / 10 minutes) and linear low-density polyethylene derived from fossil fuel are used. A mixture consisting of 15 parts (density: 0.905 g / cm3, MFR: 4 g / 10 minutes) was used.
Further, as the seal layer (C), 80 parts of (1) propylene-ethylene random copolymer (density: 0.90 g / cm3, MFR: 5.0 g / 10 minutes) and (2) propylene-. A mixture consisting of 20 parts of an ethylene random copolymer (density: 0.90 g / cm3, MFR: 8.0 g / 10 minutes) was used.
These are each supplied to three extruders and co-extruded so that the average thickness of the surface resin layer (A), the resin layer (B) and the seal layer (C) is 3: 5: 2. A three-layer film having a thickness of 30 μm was formed. Next, the surface of the seal layer (C) of the obtained film was subjected to a corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1.

The following tests and evaluations were performed using the laminated films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 above.

(1) Measurement of cloudiness degree Using the obtained film, the cloudiness degree (unit:%) is measured for one film using a heads meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) based on JIS K7105. did.

(2) Measurement of glossiness Using the obtained film, the glossiness (unit:%) was measured for one film using a heat meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) based on JIS K7105. It was measured.

(3) Measurement of Surface Roughness (Ra) Using the obtained film, the surface roughness on the surface resin layer (A) side (A) was used for one film using SURFCOM 480A manufactured by Tokyo Seimitsu Co., Ltd. based on JIS B-0601. Ra) (unit: μm) was measured.

(4) Measurement of Rigidity Using the obtained film, the 1% tangential modulus (unit: MPa) at 23 ° C. is determined by the extrusion direction (hereinafter referred to as “MD”) at the time of film production based on ASTM D-882. , Tensilon tensile tester [manufactured by ASTM Co., Ltd.].

(5) Measurement of impact strength Using the obtained film, the sample was held in a constant temperature room adjusted to 23 ° C for 6 hours, and then measured by the film impact method using a spherical impact head with a diameter of 25.4 mm. did.

(6) Film formation property Using the obtained film, the appearance of the film was visually confirmed.
◯: No holes in the film ×: Holes in the film (7) Biomass degree The biomass degree was calculated from the mixing ratio of plant-derived polyethylene contained in the film.

Table 1 shows the results obtained above.

From the results in Table 1, the laminated film using the binary system of the plant-derived high-density polyethylene / propylene homopolymer as the surface resin layer (A) of Comparative Example 1 has holes during film formation and the impact strength is also lowered. did. Since no holes were generated in the laminated film using the binary system of the high-density polyethylene / propylene homopolymer as the surface resin layer (A) of Comparative Example 2, the cause of the holes in Comparative Example 1 was the plant-derived height. It is considered that this is due to the use of high density polyethylene. On the other hand, the laminated films of Examples 1 and 2 contain a plant-derived resin, have excellent cloudiness and glossiness while achieving a high level of biomass, and have suitable rigidity, impact strength, and surface slipperiness. Since it has a film-forming property, it is suitable as a packaging film that can reduce the environmental load.

Claims (8)

1. Plant-derived high-density polyethylene (a1) with a melt flow rate of 1 g / 10 minutes or less (temperature 190 ° C., load 2.16 kg) and melt flow rate of 0.5 g / 10 minutes or more and 30 g / 10 minutes. The surface resin layer (A) containing the propylene-based resin (a2) having the following (temperature 230 ° C., load 2.16 kg) and the like.
   A matte laminated film in which a resin layer (B) containing a polyolefin resin (b1) is laminated.
   A matte laminated film comprising a propylene homopolymer (a2-1) and a propylene-ethylene block copolymer (a2-2) as the propylene-based resin (a2).
2. The matte laminated film according to claim 1, which contains a plant-derived linear low-density polyethylene (b1-1) and a propylene-based resin (b1-2) as the polyolefin-based resin (b1).
3. Claim 1 or 2 in which the usage ratio (mass ratio) (a1) / (a2) of the plant-derived high-density polyethylene (a1) and the propylene-based resin (a2) is in the range of 60/40 to 40/60. The matte laminated film described.
4. The matte laminated film according to any one of claims 1 to 3, further having a seal layer on the resin layer side.
5. The matte laminated film according to any one of claims 1 to 4, wherein the total mass of polyethylene contained in the laminated film is 20% by mass or more with respect to the mass of the laminated film.
6. A laminated body obtained by laminating another film on the laminated film according to any one of claims 1 to 5.
7. A packaging material using the laminated film according to any one of claims 1 to 5 or the laminated body according to claim 6.
8. The packaging material according to claim 7, which is a packaging bag for food.