JP6504225B2 - Sealant film and packaging material and packaging bag using the same - Google Patents

Description

  The present invention relates to a sealant film comprising a plant-derived polyethylene-based resin, and a packaging material and a packaging bag using the same, more specifically showing a high degree of biomass while exhibiting high laminate strength with an adjacent layer, In addition, the present invention relates to a sealant film excellent in slippery, and a packaging material and a packaging bag using the same.

  In recent years, in order to reduce the burden on the environment, some of the raw materials of resin films should be replaced with resins derived from petroleum, and resins mainly composed of plant-derived components (hereinafter referred to as "plant-derived resins") It is examined (patent document 1). The plant-derived resin is expected to have the same physical properties as the conventional petroleum-derived resin in terms of chemical structure.

  However, in practice, a resin film containing a plant-derived resin, for example, a sealant film containing a plant-derived polyethylene-based resin, exhibits properties different from those of a sealant film consisting only of a petroleum-derived polyethylene-based resin.

  For example, in a sealant film comprising a polyethylene-based resin derived from petroleum, a base material is laminated on a part of the raw material polyethylene-based resin when it is converted to a plant-derived polyethylene-based resin as the compounding ratio becomes higher. It was found that the laminate strength with the layer was reduced, and delamination was likely to occur.

Thus, it was difficult to achieve both high laminate strength with the substrate layer and high biomass.
With respect to this problem, although the presence of the bleed out inhibitor in the sealant film has made it possible to enhance the laminate strength with the base material layer, on the other hand, there has been a problem that the slipperiness decreases.

  Then, the slipperiness of the sealant film is reduced, so that so-called blocking phenomenon occurs in which the films adhere to each other in the film forming step, the slitting step, the bag making step, the contents filling step, etc. If the film is stored for a long time or in a high temperature state, the developability of the film at the time of use is deteriorated, and the bagging workability, the filling workability and the like are remarkably reduced.

JP, 2009-155516, A

  The present invention solves the above problems, exhibits high laminate strength with a base layer, is excellent in slipperiness, and exhibits a high degree of biomass of at least 45% as a whole film, thereby reducing environmental load. It is an object of the present invention to provide a sealed film, and a packaging material and a packaging bag using the same.

As a result of various studies, the inventor of the present invention has found that the decrease in laminate strength that occurs as the compounding ratio of the plant-derived polyethylene resin increases is caused by the low molecular weight compounds in the plant-derived polyethylene resin, such as monomers and oligomers, on the film surface. It was found that it was due to bleed out (precipitation). Furthermore, in the sealant film containing a plant-derived polyethylene-based resin, the base layer laminated surface is covered with a layer made of a petroleum-derived polyethylene-based resin containing few low molecular weight components, without reducing slipperiness. It has been found that it is possible to prevent the bleed out of the low molecular weight compound in the plant-derived resin to the base layer lamination surface and to enhance the lamination strength with the base layer.

And this invention is characterized by the following points.
1. A multi-layer laminate film comprising: a sealant film to be laminated to a substrate layer, the layer comprising one or more layers of petroleum-derived polyethylene resin and one layer or more of a layer of plant-derived polyethylene resin The outermost layer forming the base material layer laminated surface is a layer made of a petroleum-derived polyethylene resin, and the petroleum-derived polyethylene resin has a molecular weight distribution chart obtained by its gel permeation chromatography (GPC) method Area ratio of the low molecular weight region with a molecular weight of 1,000 or less is 0.5 area% with respect to the total peak area
The above sealant film, characterized in that the degree of biomass of the entire sealant film is 45 to 80%.
2. A two-layer laminated film comprising a layer consisting of a petroleum-derived polyethylene-based resin in one layer and a layer composed of a plant-derived polyethylene-based resin in one layer. The sealant film as described in.
A three-layer laminated film comprising a layer of 3.2 layers of petroleum-derived polyethylene resin and a layer of one layer of plant-derived polyethylene resin, and an outermost layer forming a base layer lamination surface, The outermost layer forming the heat seal surface on the opposite side is a layer comprising a petroleum-derived polyethylene resin, and the intermediate layer therebetween is a layer comprising a plant-derived polyethylene resin. The sealant film as described in.
4. A base material layer; ~ 3. And a layer comprising the sealant film according to any of the above.
5. Above 4. A packaging bag using the packaging material described in 4.
6. The above-mentioned 5., characterized in that it is a standing pouch for refilling. Packaging bag described in.

The sealant film of the present invention contains a resin derived from plants at a high blending ratio, that is, has a high degree of biomass. Therefore, from the viewpoint of carbon neutrality, it suppresses the increase of the amount of CO _{2 in} the atmosphere, and contributes to the saving of petroleum resource utilization.

Note that the carbon neutral, even burning plant, the amount of CO ₂ is discharged to occasion, since equal amount of CO ₂ plants absorbed during growth, affect the increase or decrease of the amount of CO ₂ in the atmosphere Point to no. Therefore, the increase in the amount of CO ₂ can be suppressed as the amount of the plant-derived material increases.

  In addition, the sealant film of the present invention has a small change in various physical properties of the film surface even after storage of the film for a long time, for example after exposure to sunlight for a long time, and is high with the substrate layer It exhibits laminate strength and excellent slipperiness, and is less likely to cause deterioration with time, delamination due to it, adhesion between films, and the like. That is, it shows excellent weather resistance.

  Furthermore, in the present invention, the film surface of the low molecular weight compound in the plant-derived polyethylene resin, since the outermost layer forming the base material layer laminated surface is a layer comprising a petroleum-derived polyethylene resin containing few low molecular weight components. Up bleed-out can be extremely effectively prevented.

In particular, in the outermost layer forming the base material layer laminated surface, the petroleum-derived polyethylene-based resin constituting the same has an area ratio occupied by low molecular weight components having a molecular weight of 1000 or less in the molecular weight distribution chart obtained by GPC. It is 0.5 area% or less with respect to an area. Thereby, even if the outermost layer has a thin layer thickness, it effectively blocks the permeation of the low molecular weight compound in the plant-derived polyethylene resin and adsorbs the slip agent etc. added to the sealant film. No slippage reduction. Thus, the sealant film of the present invention can achieve a degree of biomass as high as 80%, exhibits high laminate strength with the substrate layer, and exhibits excellent slipperiness.

  Further, the outermost layer forming the base material layer laminated surface is made of a petroleum-derived polyethylene-based resin, and those having various physical properties have been developed as the petroleum-derived polyethylene-based resin. Therefore, the petroleum-derived polyethylene-based resin that forms the base material layer lamination surface can be appropriately selected from a wide variety of options, and adjustment of the lamination strength with the base material layer, lamination conditions, and the like becomes easy.

  Also, even when the outermost layer forming the heat seal surface is a layer made of petroleum-derived polyethylene resin, petroleum-derived polyethylene suitable for desired heat seal strength and heat seal conditions among various choices The resin can be selected appropriately.

  Furthermore, the packaging material and the packaging bag comprising the sealant film of the present invention and the base material layer can suppress the reduction in the interlayer adhesion even after being subjected to the heating and cooling steps, and have excellent bagging workability and the like. It is useful as various packaging materials to show.

It is a schematic sectional drawing which shows the example about the laminated constitution of the sealant film of this invention. It is a schematic sectional drawing which shows another example about the laminated constitution of the sealant film of this invention. It is a schematic sectional drawing which shows the example about the laminated constitution of the packaging material of this invention.

  The above invention will be described in more detail below. Hereinafter, as the resin name used in the present invention, those commonly used in the industry are used. In the present invention, the density is a value measured in accordance with JIS-K7112. Moreover, MFR is a value measured based on JIS-K7210.

<I> Layer Structure of the Sealant Film of the Present Invention FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the sealant film of the present invention. As shown in FIG. 1, in the sealant film of the present invention, an optional base layer is laminated on one side, ie, the base layer laminating side [A], and the other side is a heat seal side [ B) is used by facing it with an arbitrary adherend, laminating, and heat sealing. In the following specification, the surface in contact with the base material layer of the sealant film is referred to as "substrate layer lamination surface", and the surface in contact with the adherend of the sealant film is referred to as "heat seal surface".

  Here, the sealant film is a two-layer laminated film comprising a layer [1] of one layer of petroleum-derived polyethylene resin and a layer [2] of one layer of plant-derived polyethylene resin. And, in the molecular weight distribution chart obtained by the GPC method, the petroleum-derived polyethylene-based resin constituting the layer [1] forming the base layer laminated surface has an area ratio of a low molecular weight region having a molecular weight of 1000 or less that the total peak area In contrast to the above, one having an area of 0.5% or less is used.

According to the above-mentioned configuration, while showing good laminate strength with the base material layer and excellent slip properties,
And the sealant film which shows a high degree of biomass can be manufactured easily with low cost and with sufficient productivity.

  FIG. 2 is a schematic cross-sectional view showing an example of the layer configuration of the sealant film of the present invention. As shown in FIG. 2, the sealant film of the present invention comprises two layers of petroleum-derived polyethylene resin [1, 3] and a layer of plant-derived polyethylene resin [2] sandwiched between them. It may be a three-layer laminated film consisting of And petroleum origin polyethylene system resin which constitutes layer [1] which forms this base material layer lamination side consists of a resin composition similar to a sealant film shown by the above-mentioned Drawing 1. On the other hand, the layer [3] forming the heat seal surface may be made of any petroleum-derived polyethylene-based resin. This configuration makes it possible to produce a sealant film exhibiting a high degree of biomass while exhibiting good laminate strength with the base layer, excellent slipperiness, and good heat sealability.

  FIG. 3 is a schematic cross-sectional view showing an example of the layer configuration of the packaging material of the present invention. As shown in FIG. 3, the packaging material of the present invention is obtained by laminating the base material layer [4] on the base material layer laminated surface of the sealant film of the present invention.

  The sealant film of the present invention may have any thickness depending on the application, desired seal strength, degree of biomass to be achieved, desired weather resistance, etc., but it is generally about 5 to 200 μm as a sealant film , Preferably 20 to 150 μm. Moreover, when the application is a packaging bag of a weight bag or a standing pouch for refilling, it is preferably 100 to 150 μm.

  In the sealant film, the thickness ratio of each layer is set such that the degree of biomass of the entire sealant film is 45 to 80%, more preferably 50 to 80%. The higher the thickness ratio of the layer of plant-derived polyethylene resin, the higher the degree of biomass is achieved. However, this layer is too thick compared to layer [1] made of petroleum-derived polyethylene-based resin forming the base layer laminated surface, and when the degree of biomass exceeds 80%, the low molecular weight compound is transferred to the film surface. Bleed out can not be sufficiently prevented, and the desired laminate strength can not be obtained when the base material layer is laminated.

The layer thickness of the layer [1] made of petroleum-derived polyethylene resin forming the base material layer laminated surface is at least 0.1 μm, and in the case of a weight bag or a packaging pouch of a standing pouch for refilling, preferably 3 μm or more And the thickness at which the degree of biomass of the entire sealant film is 45 to 80%.

<II> A Layer Consisting of a Plant-Derived Polyethylene-Based Resin In the present invention, “plant-derived” means containing carbon derived from a plant material, which is produced from an alcohol obtained using a plant as a material.

  In the present invention, the plant-derived polyethylene resin is a homopolymer of plant-derived ethylene derived from bioethanol obtained from plant raw materials, or a copolymer of the plant-derived ethylene and a small amount of other comonomers. .

Specifically, high density polyethylene (HDPE, density 0.940 g / cm ³ or more) obtained by polymerizing ethylene derived from bioethanol, medium density polyethylene (MDPE, density 0.925 to 0.940 g / cm) Less than ³ ), high pressure low density polyethylene (LDPE,
Density less than 0.925 g / cm ³ ), linear low density polyethylene (LLDPE, density 0.91
0 to 0.925 g / cm ³ , copolymers of ethylene and α-olefins), and mixtures thereof.

  For example, for application to sealants for weight bags and standing pouches, it is particularly preferable to use plant-derived LLDPE since a film with a suitable stiffness can be obtained and excellent impact resistance can be obtained.

  As the α-olefin to be a comonomer of the above LLDPE, an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene And mixtures thereof. These α-olefins may be plant-derived α-olefins derived from bioethanol or non-plant-derived, ie petroleum-derived α-olefins. Since a wide variety of petroleum-derived α-olefins are available, the physical properties and the like of the polyethylene-based resin can be easily adjusted by using them. By using the plant-derived α-olefin, the degree of biomass of the final product can be further enhanced.

  As a method for producing plant-derived ethylene and plant-derived α-olefin, sugar solutions and starches obtained from plants such as sugar cane, corn and sweet potato are fermented by microorganisms such as yeast according to a conventional method to produce bioethanol These can be heated in the presence of a catalyst to obtain plant-derived ethylene and plant-derived .alpha.-olefins (1-butene, 1-hexene, etc.) by an intramolecular dehydration reaction or the like. Then, using the plant-derived ethylene obtained and the plant-derived α-olefin, a plant-derived polyethylene-based resin can be produced in the same manner as in the production of a petroleum-derived polyethylene-based resin.

About the manufacturing method of plant origin ethylene, plant origin alpha-olefin, and plant origin polyethylene-type resin, it describes in detail in Japanese Patent Application Publication No. 2011-506628 etc., for example.
Examples of the plant-derived polyethylene-based resin suitably used in the present invention include green PE manufactured by Braschem SA and the like.

  In the sealant film of the present invention, the “layer made of a plant-derived polyethylene resin” is a layer formed by melting the above-mentioned plant-derived polyethylene resin and co-extruding it with a multilayer material resin. Here, in the plant-derived polyethylene-based resin, a small amount of, for example, 5% by mass or less of an additive, specifically, a slip agent (sliding agent), if necessary, as long as the effects of the present invention are not impaired. Antistatic agent, flame retardant, anti-blocking agent, crystallization accelerator, stabilizer (anti-aging agent, antioxidant, antiozonant, ultraviolet absorber, light stabilizer etc.), tackifier, softener , Colorants, coupling agents, preservatives, fungicides, etc. may be added.

<III> A Layer Consisting of a Petroleum-Derived Polyethylene-Based Resin In the present invention, “petroleum-derived” does not contain carbon derived from plant raw materials and is derived from ethylene conventionally obtained by thermal decomposition of naphtha obtained from petroleum Structure is the main component. In addition, "petroleum-derived polyethylene-based resin" refers to any polyethylene-based resin generally used as one having a heat sealability as a sealant film.

More specifically, it is a homopolymer of petroleum-derived ethylene, or a copolymer of petroleum-derived ethylene and a small amount of other comonomers, such as HDPE (density 0.940 g / cm ³ or more), MDPE (density 0. less 925 than 0.940g / cm ^3), LDPE (density less than 0.925g / cm ^3), LLDPE (density 0.910~0.925g / cm ^3, a copolymer of ethylene and α- olefin), and A mixture of these can be mentioned. As the α-olefin to be a comonomer of the above LLDPE, an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene And mixtures thereof.

  In the sealant film of the present invention, as the petroleum-derived polyethylene-based resin constituting the outermost layer forming the base layer laminated surface, a petroleum-derived polyethylene-based resin containing hardly any low molecular weight component is used. What the ratio of a molecular weight component is 0.5 area% or less, more preferably 0.3 area% or less in the molecular weight distribution chart obtained by GPC is used. Here, most of low molecular weight components having a molecular weight of 1000 or less are melt decomposition products and unreacted products of petroleum-derived polyethylene resins.

  Such a layer made of a petroleum-derived polyethylene-based resin effectively blocks the permeation of low molecular weight compounds in a plant-derived polyethylene-based resin even with a thin layer thickness, and a slip agent or the like added to a sealant film It does not adsorb and does not cause a decrease in slipperiness. Thus, the sealant film of the present invention can achieve a degree of biomass as high as 80%, exhibits high laminate strength with the substrate layer, and exhibits excellent slipperiness.

Here, in the petroleum-derived polyethylene-based resin constituting the outermost layer forming the base material layer lamination surface, when the proportion of the low molecular weight component having a molecular weight of 1000 or less is more than 0.5 area%, low in the plant-derived polyethylene-based resin The effect of preventing permeation of the molecular compound is inferior and not preferable.

  In addition, the ratio (area%) of the said low molecular weight component is a ratio with respect to the total peak area of the area which the peak of molecular weight 1000 or less occupies in the derivative molecular weight distribution chart which consists of a derivative molecular weight distribution curve obtained by GPC method. Here, the horizontal axis of the differential molecular weight distribution chart is the molecular weight (logarithmic value) obtained using polystyrene as a standard substance, and the vertical axis is the value obtained by differentiating the concentration fraction by the logarithmic value of the molecular weight is there.

The specific measurement conditions of the GPC method are as shown in Examples.
Furthermore, the petroleum-derived polyethylene-based resin forming the base layer laminated surface may be a resin composition comprising any petroleum-derived polyethylene, for example, HDPE, MDPE, LDPE, LLDPE, and a mixture thereof, From the viewpoint of preventing impact and permeation of low-molecular compounds in plant-derived polyethylene resins, petroleum-derived LLDPE is 15 to 100% by mass, preferably 50 to 100%, more preferably 60 to 100% by mass, and other petroleum-derived polyethylene It is a resin composition containing 0 to 85% by mass, preferably 0 to 50% by mass, and more preferably 0 to 40% by mass of a base resin, such as LDPE, MDPE, HDPE and the like.

  Moreover, in the said resin composition, there exists an advantage that it is excellent in hand-cutting property by mixing and using petroleum origin LLDPE and petroleum origin LDPE. On the other hand, using petroleum-derived LLDPE alone has an advantage that the effect of preventing the impact resistance and the permeation of the low molecular weight compound in the plant-derived polyethylene resin is further enhanced.

  Further, in the above resin composition, as the petroleum-derived LLDPE, although those produced using either a Ziegler catalyst or a metallocene catalyst can be used, the amount of low molecular weight components is small, so a metallocene catalyst is used. Petroleum-derived LLDPE produced in this way is more preferably used.

  In the sealant film of the present invention, a layer other than the outermost layer forming the laminated surface of the base layer, for example, a petroleum-derived polyethylene resin constituting the outermost layer forming the heat seal surface, may be made of any polyethylene resin. Can be selected appropriately and used.

  Also, in any of the layers, the petroleum-derived polyethylene-based resin may have any properties, and depending on the type of the base material layer and the adherend to be laminated in a later step, it is also desired. Those skilled in the art can appropriately determine the sealing strength, the hot tackiness, the heat sealing condition to be selected, and the like.

  For example, it is particularly preferable to use petroleum-derived LLDPE alone, or a mixture of petroleum-derived LLDPE and petroleum-derived LDPE, for application to sealants for heavy bags and standing pouches. Thereby, the film can have a suitable stiffness and excellent impact resistance. In addition, petroleum-derived LLDPE or a mixture of petroleum-derived LLDPE and petroleum-derived LDPE is used as a material resin of a layer derived from a petroleum-derived polyethylene resin, and a plant material resin is further included as a material resin of a layer derived from a plant-derived polyethylene resin. Use of the derived LLDPE is more preferable because adhesion between the layers of the sealant film is enhanced.

  In the sealant film of the present invention, the “layer made of a petroleum-derived polyethylene-based resin” is a layer formed by melting the above-mentioned petroleum-derived polyethylene-based resin and co-extrusion with the material resin of other layers. Here, in the petroleum-derived polyethylene-based resin, if necessary, a small amount of, for example, 5% by mass or less of an additive, specifically, a slip agent (sliding agent), as long as the effect of the present invention is not impaired. Antistatic agent, flame retardant, anti-blocking agent, crystallization accelerator, stabilizer (anti-aging agent, antioxidant, antiozonant, ultraviolet absorber, light stabilizer etc.), tackifier, softener , Colorants, coupling agents, preservatives, fungicides, etc. may be added.

<IV> Film Forming The sealant film of the present invention can be produced by preparing the resin or resin composition constituting each layer, melt-kneading, and co-extrusion using a conventional film forming method.
The resin film is required to have slipperiness in order to ensure processability. Then, as needed, slipperiness imparting agents such as a slip agent and an antistatic agent are blended in the film to improve the slipperiness. However, the improvement of the slip properties generally leads to a decrease in the laminate strength of the film.

  To this problem, the sealant film of the present invention has a layer made of a petroleum-derived polyethylene-based resin as the outermost layer forming the base layer laminated surface. Even if the sealant film of the present invention contains a slipperiness imparting agent such as a slip agent, this layer suppresses the bleeding out of the low molecular weight compound contained in the plant-derived polyethylene-based resin to the substrate layer lamination surface And the effect of the slip agent is not inhibited. Thus, the sealant film of the present invention can exhibit excellent slipperiness while exhibiting high laminate strength.

<V> Base Material Layer The sealant film of the present invention can be used as a laminate in which various base material layers are laminated according to the application.
The substrates to be laminated on the sealant film of the present invention may be metals, ceramics, woods, papers, etc., but in the field of packaging materials, films and / or papers made of thermoplastic resin It is often the case.

  As a thermoplastic resin which comprises a base material, olefin resin (polyethylene resin, polypropylene resin etc.), halogen containing resin (vinyl chloride resin etc.), vinyl alcohol resin, (meth) acrylic resin, styrene resin Resin, polyester resin (polyalkylene terephthalate resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate etc.), polyamide resin (polyamide 6, polyamide 66 etc), polycarbonate resin, polysulfone resin (polyether sulfone, Polysulfone etc.), polyphenylene ether resin, cellulose ester etc. can be illustrated.

Furthermore, in order to increase the degree of biomass, the substrate film may also be a plant-derived resin film. Such a film can be composed of a polylactic acid based resin, a polyester based resin, a polyamide based resin or the like. These films may be formed of a single thermoplastic resin, or may be a composite (alloy-based film) or a laminate formed of two or more thermoplastic resins.

Among these films, usually, a polypropylene resin film, a polyester resin film, a polyamide resin film, a polylactic acid resin film, etc. are often used.
These base films may be unstretched or uniaxially or biaxially stretched films.

  In addition, these base films may be composite films in which two or more are laminated. Furthermore, it is also possible to use any barrier film, for example, a material having a property of shielding light such as sunlight, or a property of transmitting no gas such as water vapor, water or oxygen.

  Specifically, for example, a metal foil such as aluminum foil, a resin film having a deposited film such as aluminum, a resin film having a deposited film of an inorganic oxide such as silicon oxide or aluminum oxide having a barrier property, water vapor, etc. A light shielding property obtained by kneading a coloring agent such as a pigment with a resin film having barrier properties, a film of resin such as polyvinyl alcohol having gas barrier properties, saponified ethylene-vinyl acetate copolymer, MXD6 nylon, etc. The various colored resin films etc. which it has can be used.

  Furthermore, the laminated surface of these base films may be surface-treated (for example, corona discharge treatment, anchor coating treatment, primer treatment, etc.) in order to enhance adhesion with the sealant film of the present invention. The thickness of the substrate film is not particularly limited, and can be selected usually in the range of about 1 μm to 2 mm, preferably about 5 μm to 1 mm, according to the application.

<VI> Lamination The lamination of the base material layer and the sealant film can be laminated by a dry lamination method via an adhesive. Examples of the adhesive to be used include a two-component curable polyurethane-based adhesive for dry lamination.

  Moreover, it can also bond together by the extrusion lamination method (what is called a sandwich lamination method) through an adhesive layer. In this case, as the adhesive layer, a polyolefin-based heat adhesive resin, for example, LDPE, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, ionomer alone, or hard resin etc. Resin etc. which blended the adhesion improving agent can be used.

Furthermore, it is also possible to laminate on the substrate film by extrusion coating the resin constituting the sealant film of the present invention.
In a further aspect of the present invention, a printing layer such as characters, figures, symbols, pictures and the like may be provided on the substrate film or between the sealant film and the substrate film.
The degree of biomass can be further enhanced by using an adhesive or a printing ink containing a plant-derived resin as the adhesive or printing ink used above.

<VII> Packaging material The laminated film which has the said base material layer and the sealant film of this invention can be suitably used as packaging materials, such as a lid material and a packaging bag. For example, the laminated film is folded in two or two sheets of the laminated film are prepared, the surfaces of the sealant film are made to face each other, and the peripheral end is laminated, for example, side seal type, two way seal Heat-seal by heat seal form such as mold, three-way seal, four-way seal, envelope-sealed seal, combined palm-sealed seal (pillow seal), crimped seal, flat-bottomed seal, square-bottomed seal, gusset type Thus, various forms of packaging bags can be made.

  In the above, as a method of heat sealing, it can carry out by publicly known methods, such as bar seal, rotation roll seal, belt seal, impulse seal, high frequency seal, ultrasonic seal etc., for example.

  The sealant film of the present invention exhibits high degree of biomass while exhibiting high laminate strength with the adjacent substrate layer and also exhibits excellent slipperiness. Therefore, it can be suitably used as a packaging material for various uses. In particular, the packaging material using the sealant film of the present invention can be suitably used as a weight bag or a standing pouch for refilling, which has a large internal volume with respect to the film area used.

<VIII> Biomass Degree The “biomass degree” is an index that represents the mixing ratio of the petroleum-derived material and the plant-derived material (biomass), and is determined by measuring the concentration of radioactive carbon (C ¹⁴ ) , It is represented by the following formula.
Biomass degree (%) = C ¹⁴ concentration (pMC) × 0.935
The C ¹⁴ is during a plant-derived raw material include a constant concentration, hardly present in petroleum trapped underground. Therefore, by measuring the concentration of C ¹⁴ by accelerator mass spectrometry, it can be used as an indicator of the content rate of the plant-derived material.

  The sealant film of the present invention contains a plant-derived resin at a high blending ratio and exhibits a biomass as high as 45 to 80%, more preferably as high as 50 to 80%, while exhibiting excellent weatherability and high laminate strength with an adjacent layer. Can indicate the degree. If the layer of plant-derived polyethylene resin is thickened so that the degree of biomass exceeds 80%, bleed-out to the film surface can not be sufficiently prevented, and the desired laminate strength is obtained when the base layer is laminated. I can not.

In the present invention, the measurement of the concentration of C ¹⁴ in the film is performed as follows. That is, the sample to be measured is burned to generate carbon dioxide, and carbon dioxide purified by a vacuum line is reduced with hydrogen using iron as a catalyst to purify graphite. Then, the graphite, by mounting the C ¹⁴ AMS-only apparatus which is based on Tandem accelerator (manufactured by NEC Corporation), the count of C ^14, the concentration of the concentration ^{(C 13 / C 12),} C 14 of C ¹³ ( The measurement of C ¹⁴ / C ¹² ) is performed, and the ratio of the C ¹⁴ concentration of the sample carbon to the standard modern carbon is calculated from the measured value. As a standard sample, oxalic acid (HOX II) provided by the National Institute of Standards (NIST) is used.

  The present invention will be described in more detail based on examples given below, but the present invention is not limited by these examples.

[GPC method]
In the present invention, the molecular weight distribution of the petroleum-derived polyethylene-based resin and the ratio of low molecular weight components were measured by GPC under the following conditions.
Device: GPC-150 manufactured by Waters
Column: Showa Denko KK GPC HT-806m × 2, HT-803 × 1 Eluent: Dichlorobenzene (140 ° C)
Flow rate: 1 mL / min Sample concentration: 1 g / L
Injection volume: 5 mL
Detector: Infrared spectrometer Measurement temperature: 0 to 140 ° C
Reference material: polystyrene

Example 1
Petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd., density 0.9)
16 kg / m ³ , MFR = 2.3 g / 10 min) 70% by mass, petroleum-derived LDPE (Ube Maruzen Polyethylene Co., Ltd. LDPE-F 120 N, density 0.920 kg / m ³ , MFR = 1.2 g
A first resin composition was prepared by sufficiently melt-kneading 29% by mass and 1% by mass of a slip agent (M-3 manufactured by Nippon Unicar Co., Ltd.) per 10 minutes. The proportion of low molecular weight components having a molecular weight of 1,000 or less in the first resin composition was 0.5 area%.

In addition, plant-derived LLDPE (Brasschem C4-SLL118, density 0.916 kg
/ M ³ , MFR = 1.0 g / 10 min, degree of biomass 87%) 99% by mass and 1% by mass of slip agent (Nippon Unicar Co., Ltd. M-3) are sufficiently melt-kneaded to obtain a second resin The composition was adjusted.

  The first and second resin compositions are used to form a film by a top-blowing air-cooled inflation co-extrusion film-forming machine, and the first resin composition (base layer laminated surface, thickness 25 μm) / second resin composition A sealant film of the present invention was produced, which was composed of three layers (intermediate layer, thickness 70 μm) / first resin composition (heat seal surface, thickness 25 μm). The biomass degree was 50%.

Example 2
In the first resin composition, instead of petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd.), petroleum-derived LLDPE (Evolue SP1540 manufactured by Prime Polymer Co., Ltd .; density 0.913 kg / m ³ ; MFR = 3. A sealant film of the present invention was produced in the same manner as in Example 1 except that 8 g / 10 min) was used. The proportion of low molecular weight components having a molecular weight of 1,000 or less in the first resin composition was 0.3 area%. In addition, the biomass degree was 50%.

[Example 3]
Petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd., density 0.9)
A first resin composition was prepared by sufficiently melt-kneading 99% by mass of 16 kg / m ³ , MFR = 2.3 g / 10 min) and 1% by mass of a slip agent (N-UNIKA Co., Ltd. M-3). did. The proportion of low molecular weight components having a molecular weight of 1,000 or less in the first resin composition was 0.4 area%.

In addition, plant-derived LLDPE (Brasschem C4-SLL118, density 0.916 kg
/ M ³ , MFR = 1.0 g / 10 min, degree of biomass 87%) 99% by mass and 1% by mass of slip agent (Nippon Unicar Co., Ltd. M-3) are sufficiently melt-kneaded to obtain a second resin The composition was adjusted.

  The first and second resin compositions are used to form a film by a top-blowing air-cooled inflation co-extrusion film-forming machine, and the first resin composition (base layer laminated surface, thickness 10 μm) / second resin composition A sealant film of the present invention was produced, which was composed of two layers (heat seal surface, thickness 120 μm). The biomass degree was 80%.

Comparative Example 1
In the first resin composition, in place of petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd.), petroleum-derived LLDPE (Ultrazex 2022 L manufactured by Prime Polymer Co., Ltd., density 0.919 kg / m ³ , MFR = 2) A sealant film was produced in the same manner as in Example 1 except that .0 g / 10 min) was used. The proportion of low molecular weight components having a molecular weight of 1,000 or less in the first resin composition was 0.6 area%. In addition, the biomass degree was 50%.

Comparative Example 2
In the first resin composition, instead of petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd.), petroleum-derived LDPE (Novatec LD manufactured by Nippon Polyethylene Co., Ltd., LC600A density 0.918 kg / m ³ , MFR = 7 A sealant film was produced in the same manner as in Example 3 except that .2 g / 10 min) was used. The proportion of low molecular weight components having a molecular weight of 1,000 or less in the first resin composition was 3.3 area%. In addition, the biomass degree was 80%.

Comparative Example 3
Plant-derived LLDPE (Braschem C4-SLL 118, density 0.916 kg / m ³ , MFR = 1.0 g / 10 min, degree of biomass 87%) 58 mass%, petroleum-derived LLDPE ((
Evolue SP2020, manufactured by Prime Polymer Co., Ltd., density 0.916 kg / m ³ , MFR = 2.3 g / 10 min) 12 mass%, petroleum-derived LDPE (Ube Maruzen Polyethylene Co., Ltd. LDP)
Obtained by sufficiently melt-kneading E-F 120N, density 0.920 kg / m ³ , MFR = 1.2 g / 10 min) 29% by mass, and slip agent (Nippon Unicar Co., Ltd. product M-3) 1% by mass The resulting resin composition was formed into a film by a top-blowing air-cooling inflation co-extrusion film-forming machine to produce a 120 μm-thick sealant film. The biomass degree was 50%.

Comparative Example 4
Petroleum-derived LLDPE (Evolue SP2020 manufactured by Prime Polymer Co., Ltd., density 0.9)
16 kg / m ³ , MFR = 2.3 g / 10 min) 70% by mass, petroleum-derived LDPE (Ube Maruzen Polyethylene Co., Ltd. LDPE-F 120 N, density 0.920 kg / m ³ , MFR = 1.2 g
Melt-kneading of 29% by mass and 1% by mass of slip agent (M-3 manufactured by Nippon Unicar Co., Ltd.), and the obtained resin composition is manufactured by a top-blowing air-cooling inflation co-extrusion film forming machine The membrane was formed to produce a 120 μm thick sealant film. The biomass degree was 0%.

[Evaluation]
(Laminated strength)
Corona treatment is applied to the base material layer lamination surface of the sealant film of Examples 1 to 3 and one surface of the sealant film of Comparative Examples 1 to 2, and biaxially oriented nylon on the treated surface through the adhesive layer. The film (thickness 15 μm) was dry laminated to produce a laminated film. The laminated film was aged at 40 ° C. for 3 days, and further after 2 weeks at 23 ° C., the laminate strength was evaluated as T-peel, tensile rate of 50 mm / min. It measured by.

(Slippery)
Two sealant films of Examples 1 to 3 and Comparative Examples 1 to 2 are prepared, respectively, and slip property of film (heat seal surface) to film (heat seal surface) is measured according to JIS K 7125: 1999 (friction coefficient test method). The coefficient of friction was measured according to the standard.
The results are shown in Table 1 below.

The sealant films of Examples 1 to 3 have excellent laminate strength and slip which are equivalent to the sealant film of Comparative Example 4 (biomass degree 0%) despite having biomass degree as high as 50 to 80%. Showed sex.
On the other hand, the sealant films of Comparative Examples 1 and 2 were somewhat inferior in laminate strength. Moreover, the sealant film of Comparative Example 3 was further inferior in laminate strength.

(Pouch appearance)
About the sealant film of Examples 1-3 and Comparative Examples 1-4, it carried out similarly to said lamination strength measurement, produced the laminated film, and obtained the packaging material for the trunk material of a pouch.

  Separately from this, the first resin composition of Example 3 was used to form a film by a top-blowing air-cooling inflation co-extrusion film-forming machine to produce a single-layer sealant film (130 μm in thickness). About the obtained sealant film, it carried out similarly to said lamination strength measurement, produced the laminated film, and obtained the packaging material for the bottom material of a pouch.

  Using the obtained packaging material for body material and base material, a standing pouch having an outer dimension of 230 mm in height × 130 mm in width, a height of 40 mm in a folded portion at the bottom, and a seal width of 5 mm was manufactured. In addition, the bottom was heat-sealed by a bottom-to-bottom seal pattern.

Ten pouches manufactured as described above were prepared for each example / comparative example, 380 cc of water was filled in each pouch, heat sealed and sealed. Then, after storing these pouches for 3 days at 3 ° C., from the height of 1.2 m, horizontally with the floor (with the body touching the floor) 5
The change in appearance of the pouch was visually observed by dropping it 5 times so that the bottom and the floor were in contact with the floor.
The results are shown in Table 2 below.

  The pouches using the sealant films of Examples 1 to 3 and Comparative Example 4 retained a beautiful appearance after the test. On the other hand, in the pouches using the sealant films of Comparative Examples 1 and 2, delamination was observed in part of the films under the impact of falling, and the appearance was inferior. Moreover, in the pouch using the sealant film of Comparative Example 3, the delamination of the film was observed in a larger area than Comparative Examples 1 and 2, and the appearance was further inferior.

A. Base layer laminated surface B. Heat seal surface 1, 3. Layer made of petroleum-derived polyethylene-based resin Layer composed of plant-derived polyethylene resin 4. Base layer

Claims (6)

A sealant film formed by coextrusion ,
A multilayer laminate film comprising a layer comprising one or more petroleum-derived polyethylene resins and a layer comprising one or more plant-derived polyethylene resins,
The outermost layer forming the laminated surface with the base material layer is a layer made of a petroleum-derived polyethylene-based resin,
The petroleum-derived polyethylene-based resin for preventing bleeding out of the low molecular weight compound in the plant-derived polyethylene-based resin to the surface of the base layer-laminated surface and enhancing the laminate strength with the substrate layer , which forms the outermost layer, In the molecular weight distribution map obtained by the ion chromatography method, the area ratio of the low molecular weight region having a molecular weight of 1,000 or less is 0.5 area% or less with respect to the total peak area,
The petroleum-derived polyethylene-based resin is a resin in which petroleum-derived LLDPE and petroleum-derived LDPE are mixed,
The above sealant film, wherein the degree of biomass of the entire sealant film is 45 to 80%.   The sealant film according to claim 1, wherein the sealant film is a two-layer laminated film comprising a layer consisting of one layer of petroleum-derived polyethylene resin and a layer consisting of one layer of plant-derived polyethylene resin. A three-layer laminated film comprising a layer consisting of two layers of petroleum-derived polyethylene resin and a layer consisting of one layer of plant-derived polyethylene resin,
In addition to the outermost layer forming the base material layer laminated surface, the outermost layer forming the heat seal surface on the opposite side is also a layer made of a petroleum-derived polyethylene resin,
The sealant film according to claim 1, wherein the intermediate layer between them is a layer made of a plant-derived polyethylene resin.   A packaging material comprising a base material layer and a layer comprising the sealant film according to any one of claims 1 to 3.   A packaging bag comprising the packaging material according to claim 4.   The packaging bag according to claim 5, characterized in that it is a refilling standing pouch.

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