JP7459986B2 - Laminate for hand-tearable packages having a sealant layer containing plant-derived polyethylene - Google Patents

Description

In the present invention, at least a base material layer, an adhesive resin layer, a barrier layer, and a sealant layer are laminated in this order, and the sealant layer contains linear low-density polyethylene and plant-derived low-density polyethylene in a specific ratio. The present invention relates to laminates, packaging materials, and packages for hand-cut and sealed packages containing low-density polyethylene containing The present invention relates to a laminate, a packaging material, and a package that exhibits bag breakability and a high degree of biomass.

In recent years, in order to reduce the burden on the environment, consideration has been given to replacing some of the raw materials for polyethylene resin films such as sealant films from fossil fuel-derived polyethylene with plant-derived polyethylene (Patent Document 1). Plant-derived polyethylene is chemically structurally the same as conventional fossil fuel-derived polyethylene, and is expected to have equivalent physical properties.

However, in reality, a resin film containing plant-derived polyethylene does not exhibit properties equivalent to those of a resin film made only of fossil fuel-derived polyethylene.
In particular, it was found that resin films containing plant-derived polyethylene have reduced blocking resistance, ease of being cut by hand, and drop impact resistance when used as a sealant film as the plant-derived polyethylene content increases and the biomass content increases.
Therefore, polyethylene films with a high biomass content are unsuitable as sealant films for packaging materials that require blocking resistance, ease of cutting by hand, and resistance to impact when dropped, and are therefore lacking in practical use.

Japanese Patent Application Publication No. 2009-155516

The present invention aims to solve the above problems and provide a laminate for packaging materials, packaging materials, and packages that contain plant-derived polyethylene in the sealant layer, thereby reducing the burden on the environment while providing excellent productivity, blocking resistance, ease of opening by hand, and resistance to bag tearing.

As a result of various studies, the present inventors have found that a laminate having a specific layer structure, in which a sealant layer contains a linear low-density polyethylene and a low-density polyethylene containing a plant-derived low-density polyethylene in a specific ratio, can achieve the above-mentioned object.
The present invention is characterized in the following points.
1. A laminate for a hand-cut open package, comprising at least a base layer, an adhesive resin layer, a barrier layer, and a sealant layer, laminated in this order,
The adhesive resin layer contains low-density polyethylene,
The barrier layer and the sealant layer are adjacent to each other directly or via an anchor coat layer,
The base layer is made of a film laminated with one or more layers selected from a polyester film, a polypropylene film, and a synthetic paper,
the barrier layer is one or more selected from the group consisting of a metal foil, a metal vapor deposition film, and a metal oxide film;
the sealant layer is an outermost layer on one surface of the laminate,
the sealant layer has a two-layer structure consisting of a first sealant layer which is an outermost surface layer of the sealant layer, and a second sealant layer adjacent to the first sealant layer, the first sealant layer being made of linear low-density polyethylene derived from a fossil fuel,
the second sealant layer is a vegetable-derived low density polyethylene;
a thickness ratio of the second sealant layer to the first sealant layer is 1/1 or more and 7/3 or less;
The total thickness of the sealant layer is 25 μm or more and 40 μm or less.
A laminate for a hand-tearable package, comprising:
2. The laminate according to claim 1, wherein the adhesive resin layer contains a plant-derived low-density polyethylene.
3. The laminate according to the above item 1 or 2, wherein the adhesive resin layer and the barrier layer are adjacent to each other.
4. The laminate according to any one of 1 to 3 above, wherein the base layer contains a resin film made of recycled polyester or plant-derived polyester.
5. The laminate according to any one of 1 to 4 above, characterized in that the laminate has a half-cut line for manual tearing, the half-cut line being formed so as to penetrate the base material layer but not to penetrate the barrier layer and the sealant layer.
6. The laminate according to any one of 1 to 5 above, characterized in that the laminate has a group of marks for manual tearing, the group of marks being formed so as to penetrate the base layer but not the barrier layer and the sealant layer.
7. The laminate according to any one of 1 to 6 above, wherein the content of the C4 linear low density polyethylene in all the sealant layers is 45% by mass or more and 70% by mass or less.
8. The laminate according to any one of 1 to 7 above, wherein the linear low-density polyethylene is synthesized using a Ziegler-Natta catalyst.
9. A packaging bag produced using a packaging material produced from the laminate according to any one of 1 to 8 above.

The laminate, packaging material, and packaging body of the present invention contain plant-derived polyethylene and exhibit excellent productivity, blocking resistance, manual tear-sealing property, and bag breakage resistance while reducing the burden on the environment. .
From the perspective of carbon neutrality, we can suppress the increase in the amount of _CO2 in the atmosphere, and
It can also contribute to saving on the use of petroleum resources.
Carbon neutral means that even if you burn plants, the amount of CO ₂ emitted during that process is equal to the amount of CO ₂ absorbed by the plants during growth, so it does not affect the increase or decrease in the amount of CO ₂ in the atmosphere. It refers to something that is not there. Therefore, the more plant-derived raw materials are included, the more the amount of CO ₂ can be suppressed.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a sealant film (single layer) for packaging materials of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a laminate for a packaging material of the present invention. FIG. 1 is a front view showing an example of the structure of a refill pouch formed using the packaging material of the present invention.

The present invention will be explained in more detail below.
The resin names used in the present invention are those commonly used in the industry.
In the present invention, density is a value measured in accordance with JIS K 6760 (1981) for a 1 mm thick sheet obtained by press molding at 150°C, and MFR is a value measured in accordance with JIS K 7210 (1995). According to the test temperature 190℃, test load 21.18
This is the value measured in N.

<Laminated body>
The laminate for a hand-cut and sealed package of the present invention has at least a base material layer, an adhesive resin layer, a barrier layer, and a sealant layer, which are laminated in this order, and the sealant layer is on one side of the laminate. It is the outermost layer and is adjacent to the barrier layer either directly or via an anchor coat layer.
The base material layer and the barrier layer are preferably laminated by a sandwich lamination method via a melted resin composition for the adhesive resin layer.
Furthermore, it is preferable that the laminate has half-cut lines and/or scar groups for manual cutting and sealing. By having these, it is possible to improve the manual tearing and sealing properties of the laminate, packaging materials and packages made from the laminate.

(Base layer)
The substrate layer may contain any resin film or sheet depending on the application of the laminate. For example, when applied to a refill pouch for sealing and packaging refillable shampoo, rinse, food, etc., it is preferable that the film has excellent mechanical strength such as tensile strength, flexural strength, impact strength, etc., and excellent printability. For example, biaxially oriented nylon film, biaxially oriented polyester film such as biaxially oriented polyethylene terephthalate film, biaxially oriented polypropylene film, etc. can be suitably used, and synthetic paper, etc. can also be used. These may be used alone or in combination.

Among the above resin films, it is preferable to include a resin film made of polyester, and more preferably a resin film made of recycled polyester and/or plant-derived polyester.
The adhesive strength between the layers can be increased by applying an anchor coating agent to the laminated surface of the base material layer in advance or performing a pretreatment such as corona treatment.

(Adhesive resin layer)
The adhesive resin layer included between the base layer and the barrier layer preferably contains low density polyethylene (LDPE).
By containing low-density polyethylene as the adhesive resin layer, the base material layer and barrier layer can be easily laminated by the sandwich lamination method, exhibiting excellent productivity and adhesion, and making packaging bags tear-resistant. It can also improve your sexuality.
Furthermore, the low-density polyethylene may be fossil fuel-derived low-density polyethylene, plant-derived low-density polyethylene, or a mixture of both. Therefore, it is preferable to contain plant-derived low density polyethylene.
An adhesive resin layer may be provided between the base material layer and the barrier layer, and a dry lamination adhesive or an extrusion adhesive may be used.

(barrier layer)
The barrier layer is a layer that imparts gas barrier properties to the laminate, and the barrier layer is preferably adjacent to the adhesive resin layer and bonded to the base material layer via the adhesive resin layer. When adhering, the adhesive strength between the layers can be increased by applying an anchor coating agent to the laminated surface of the barrier layer in advance or performing a pretreatment such as corona treatment.
The barrier layer is preferably one or more selected from the group consisting of metal foil, metal vapor deposited film, and metal oxide film, and among these, metal foil is more preferred.
Examples of the metal foil include aluminum foil, examples of the metal vapor deposited film include aluminum, silicon, etc., and examples of the metal oxide film include aluminum oxide, silicon oxide, and the like.
The above metal vapor deposited film and metal oxide film can also be used in the form of a film with a vapor deposited film deposited on a resin film. As the resin film, biaxially stretched polyethylene terephthalate film, polyacrylonitrile film, ethylene-vinyl alcohol copolymer film, etc. can be used.

(Sealant Layer)
In the laminate of the present invention, the sealant layer is the outermost layer on one side of the laminate and is adjacent to the barrier layer directly or via an anchor coat layer.
The sealant layer of the laminate of the present invention preferably contains a low density polyethylene and a linear low density polyethylene.
Here, the mass ratio of low-density polyethylene/linear low-density polyethylene is preferably in the range of 3/7 or more and 7/3 or less, and the low-density polyethylene preferably contains plant-derived low-density polyethylene.

The sealant layer may contain any thermoplastic resin generally used as a constituent of a sealant film. For example, depending on the purpose, a resin having various functions such as a resin having excellent low-temperature sealability, a resin having excellent content resistance, a resin having excellent adhesiveness, a resin that increases the stiffness of the entire film and contributes to thinning the film, etc. may be selected.
The mass ratio of the linear low-density polyethylene to the low-density polyethylene is preferably in the range of 3/7 to 7/3. If it is lower than the above range, the laminate or the packaging bag will elongate greatly when torn, which tends to deteriorate the ease of opening by hand, and the seal strength tends to be low, so that the packaging bag may not be able to withstand impacts such as being dropped, resulting in a decrease in resistance to bag breakage. If it is higher than the above range, the tear strength of the laminate will be too high to be cut by hand, and scissors or the like will likely be required.
Furthermore, the low-density polyethylene contained in the sealant layer preferably contains plant-derived low-density polyethylene.

The sealant layer preferably has a multi-layer structure of two or more layers having the same or different compositions.
For example, when the outermost surface layer in the sealant layer is a first sealant layer and the layer adjacent to the inside of the first sealant layer is a second sealant layer, the first sealant layer preferably contains a linear low-density polyethylene derived from a fossil fuel, the second sealant layer preferably contains a plant-derived low-density polyethylene, and the thickness ratio of the second sealant layer/the first sealant layer is preferably 3/7 or more and 7/3 or less.
In addition, it is preferable that the first sealant layer does not contain a plant-derived polyethylene resin.

The sealant layer may have a third sealant layer or the like further inside, but it must have a two-layer structure consisting only of the first sealant layer and the second sealant layer adjacent to the barrier layer. is preferred.
The total thickness of the sealant layer is preferably in the range of 25 μm or more and 40 μm or less. When it is smaller than the above range, the reduction in environmental load is small, and when it is larger than the above range, the hand-cutting properties and drop impact resistance of the sealant film tend to deteriorate.
The total thickness of the adhesive resin layer and sealant layer between the base material layer and the barrier layer is preferably 50 μm or more and 90 μm or less. Within the above range, it is easy to achieve an excellent balance between adhesive properties, sealing properties, and high biomass content. The biomass content of the sealant layer is 10% or more,
It is preferably 50% or less.
If it is smaller than the above range, the biomass degree of the laminate will be low, and the environmental load reduction effect will likely be low.
Examples of the method for laminating the sealant layer include a method of laminating the sealant layer on the barrier layer by a melt (co)extrusion coating method.

The sealant layer may contain any additives as long as the effects of the present invention are not significantly impaired. Additives include various resin additives that are commonly used to adjust moldability, productivity, and various physical properties of resin films, such as anti-blocking agents, slip agents, antioxidants, pigments, and flow control agents. materials, flame retardants, fillers, ultraviolet absorbers, surfactants, etc.
The sealant layer can be formed from a polyethylene resin composition containing the above-mentioned polyethylene resin, thermoplastic resin, additives, and the like.

(Half cut line)
The half-cut line can be formed by processing using a known laser or cutter.
The half-cut line is formed so as to penetrate the base layer but not the barrier layer and the sealant layer. The half-cut line may or may not penetrate the adhesive layer, depending on the processing method of the half-cut line. For example, the half-cut line may penetrate when processed with a laser, but may not penetrate when processed with a cutter or the like.
By having a half-cut line in the laminate, the laminate and the packaging material and package made from the laminate have improved hand-tear-opening properties.
There is no particular limit to the number of half-cut lines, and the number may be one, two or more.
When there are two or more half-cut lines, the half-cut lines may be parallel or convergent, or may be arranged in a combination of multiple parallel half-cut lines and diagonal half-cut lines that diagonally intersect the parallel half-cut lines.

(scar group)
The scar group can be formed by processing with a known laser or cutter.
The scar group is formed so as to penetrate the base material layer but not the barrier layer and the sealant layer. The adhesive layer may or may not be penetrating, depending on the method of processing the scar group. For example, when processing with a laser, it may be penetrating, but when processing with a cutter or the like, it does not need to be penetrating.
By having the scar group in the laminate, the laminate and packaging materials and packages made from the laminate have improved manual tear-sealability.
There are no particular restrictions on the pattern or width of the scar group, or the shape or number of scars.

[Polyethylene resin]
Polyethylene is classified into fossil fuel-derived polyethylene resins and plant-derived polyethylene resins depending on the raw materials from which it is derived, and is further classified into linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) depending on its molecular structure, density, and MFR.
That is, for example, plant-derived polyethylene resins include plant-derived linear low-density polyethylene and plant-derived low-density polyethylene.

Furthermore, examples of catalysts used in the polymerization include single-site catalysts such as metallocene catalysts and multi-site catalysts such as Ziegler-Natta catalysts. In the case of a single-site catalyst such as a metallocene catalyst, polyethylene excellent in structural uniformity, strength, transparency and sealability and in a well-balanced relationship between physical properties and moldability can be obtained, while in the case of a multi-site catalyst such as a Ziegler-Natta catalyst, polyethylene excellent in mechanical properties can be obtained.
In the present invention, copolymers of ethylene with various unsaturated compounds are also considered to be a type of polyethylene.
Furthermore, in the present invention, the term "based resin" is added as a general term for various types, for example, polyethylene-based resin is also used as a general term for various types of polyethylene.

(Fossil fuel-derived polyethylene resin)
In the present invention, the fossil fuel-derived polyethylene resin refers to polyethylene that is produced, without using raw materials derived from plants, by polymerizing ethylene obtained by thermal decomposition of naphtha obtained from petroleum, and α-olefins (1-butene, 1-hexene, etc.) as raw materials, as in the conventional method.
Generally, the polymerization method used for low density polyethylene is a high pressure method, and for linear low density polyethylene, a high pressure method, a slurry method, a solution method, a gas phase polymerization method or the like is used.

(Plant-derived polyethylene resin)
In the present invention, "plant-derived" means containing carbon derived from plant raw materials, which is produced from alcohol obtained using plants as raw materials.
The plant-derived polyethylene resin can be selected to have an appropriate density and MFR depending on the physical properties of the petroleum-derived polyethylene resin used together and the application of the sealant film.

The method for producing plant-derived polyethylene is to produce bioethanol by fermenting sugar solution and starch obtained from plants such as sugar cane, corn, and sweet potatoes using microorganisms such as yeast, and then fermenting this in the presence of a catalyst. Ethylene and α-olefins (1-butene, 1-hexene, etc.) are obtained through intramolecular dehydration reaction and the like. Next, by using these as monomers and polymerizing them in the presence of a conventional catalyst in the same manner as in the production of petroleum-derived polyethylene, a plant-derived polyethylene resin can be produced. In some cases, petroleum-derived α-olefins can also be used as the comonomer species.
The catalyst and polymerization method during polymerization are the same as those for fossil fuel-derived polyethylene resins.

(Low density polyethylene)
Low density polyethylene is polyethylene that is radically polymerized under high pressure of 100 to 400 MPa.
The low-density polyethylene used in the present invention has a density of 0.920 kg/m3 or ^more .
The viscosity is preferably 0.933 kg/ ^m3 or less, and more preferably 0.920 kg/ ^m3 or more and 0.925 kg/ ^m3 or less. The MFR is 0.5 g/10 min or more and 3.5 g/10 min or less.
It is preferable that the viscosity is 0.8 g/10 min or less, and more preferable that the viscosity is 0.8 g/10 min or more and 3.0 g/10 min or less.

(Linear low density polyethylene)
Linear low-density polyethylene is polyethylene in which ethylene and α-olefin are polymerized under low pressure of normal pressure to 1 MPa using a transition metal catalyst such as a Ziegler catalyst or a metallocene catalyst.
In the present invention, the linear low density polyethylene may include C4 linear low density polyethylene and/or C6 linear low density polyethylene.
Here, C4 linear low-density polyethylene is a linear low-density polyethylene made of a copolymer of ethylene and 1-butene, and C6 linear low-density polyethylene is a copolymer of ethylene and 1-hexene. It is a linear low-density polyethylene made of a copolymer.
Among these linear low-density polyethylenes, one synthesized using a Ziegler-Natta catalyst is preferable because it has excellent hand cutability and tearability when included in the sealant layer.

The C4 linear low density polyethylene used in the present invention has a density of 0.910 kg/
It is preferable that it is 0.930 kg/m ³ or more and 0.930 kg/m ³ or less. The MFR is preferably 0.9 g/10 minutes or more and 3.0 g/10 minutes or less, more preferably 0.9 g/10 minutes or more and 2.7 g/10 minutes or less.

The content of the C4 linear low density polyethylene in the entire sealant layer is preferably 45% by mass or more and 70% by mass or less.
If the thickness is smaller than the above range, the package stretches when torn, making it difficult to tear by hand, and the seal strength is likely to be low, so that the package cannot withstand an impact such as being dropped and may break. If the thickness is larger than the above range, the tear strength of the package becomes too high to be torn by hand, and scissors or the like are likely to be required.
The content of the plant-derived C4 linear low-density polyethylene in the entire sealant layer is preferably 10% by mass or more and 60% by mass or less.

The density of C6 linear low density polyethylene is 0.930 g/cm ³ or more, 0.950 g/c
It is preferably less than m ³ , more preferably 0.935 g/cm ³ or more and less than 0.945 g/cm ³ . MFR is preferably 0.9 g/10 minutes or more and 3.0 g/10 minutes or less, more preferably 0.9 g/10 minutes or more and 2.7 g/10 minutes or less.
When the density and MFR are outside the above ranges, drop impact resistance tends to decrease.

The total content of the C4 linear low density polyethylene and the C6 linear low density polyethylene in the entire sealant layer is preferably 60% by mass or more and 85% by mass or less.
If the content is less than the above range, the package stretches when torn, making it difficult to tear by hand, and the seal strength is likely to be low, so that the package bag may not be able to withstand an impact such as being dropped and may break. If the content is greater than the above range, the tear strength of the package becomes too high, making it difficult to cut by hand and often requiring scissors or the like.

The mass ratio of C4 linear low density polyethylene/C6 linear low density polyethylene in the entire sealant layer is more preferably greater than 2 and less than or equal to 5.
If the mass ratio is smaller than the above range, the tear strength of the package will be too high to be cut by hand, and scissors or the like will likely be required. If it is larger than the above range, the package will stretch when it is torn, making it difficult to cut by hand, and the sealing strength will also tend to decrease, so the packaging bag will not be able to withstand the impact of being dropped and the bag will break. There is a possibility that

(Biomass degree)
Biomass degree is an index that expresses the mixing ratio of raw materials derived from fossil fuels and raw materials derived from plants (biomass), and is determined by measuring the concentration of radioactive carbon ( ¹⁴ C), and is expressed by the following formula. .
Biomass degree (%) = ¹⁴ C concentration (pMC) x 0.935
This ¹⁴ C is contained at a certain concentration in plant-derived raw materials, but it is hardly present in fossil fuels trapped underground. Therefore, by measuring the concentration of ¹⁴ C by accelerator mass spectrometry, it can be used as an indicator of the content ratio of plant-derived raw materials.

In the present invention, the concentration of ¹⁴ C in the laminate is measured by burning the laminate, which is the sample to be measured, to generate carbon dioxide, collecting and purifying it in a vacuum line, and reducing it with hydrogen using iron as a catalyst. and generate graphite. Then, this graphite was filled into a ¹⁴ C-AMS dedicated device (manufactured by NEC Corporation) based on a tandem accelerator, and the ¹⁴ C count, ¹³ C concentration ( ¹³ C/ ¹² C), and ¹⁴ C concentration ( ¹⁴ C/ ¹² C) is measured, and from this measurement value the ratio of the ¹⁴ C concentration of the sample carbon to the standard modern carbon is calculated. As the standard sample, use the oxalic acid standard sample (HOxII) provided by the U.S. National Institute of Standards (NIST).

<Packaging materials>
The packaging material of the present invention is a packaging material produced using the laminate of the present invention.

<Package>
The packaging body of the present invention is a packaging body produced using the packaging material of the present invention, for example, by using the packaging material of the present invention and folding it in half, or by preparing two packaging materials. , overlap the sealant layers with their surfaces facing each other, and then seal the peripheral edges of the sealant layer, for example, side seal type, two side seal type, three side seal type, four side seal type, envelope sticker type, gassho sticker type (pillow sticker type). Various types of packaging bags can be manufactured by heat sealing using heat sealing methods such as a sealed type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type.

The packaging body of the present invention has a high biomass content while exhibiting excellent hand-tearability and drop impact resistance, and can therefore be particularly suitably used as a sealant film for refill pouches for hermetically packaging refillable shampoos, conditioners, foods, and the like.
In the above, the heat sealing can be performed by a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

FIG. 3 is a front view showing an example of the structure of a refill pouch, which is one embodiment of the package.
The refill pouch 100 shown in FIG. 3 is manufactured in the form of a standing pouch, and the bottom of the pouch is placed between the lower parts of the front and rear wall films 11 and 11' made of the packaging material of the present invention. The material may be the same as or different from the wall film) is folded inward and inserted up to the bottom film folded part 12 to form a gusset part 14, and both sides of the bottom film folded inward are formed. In this case, semicircular bottom film notches 13a and 13b are provided near the lower end, and the gusset portion 14 is heated with a boat bottom-shaped bottom seal portion 15 whose inner side is concave in a curved line from both sides to the center. The body of the pouch is formed by heat-sealing the edges of both sides of the front and rear wall films 11 and 11' with side seal parts 16a and 16b, and the body of the pouch is formed by heat-sealing the edges of both sides of the front and rear wall films 11 and 11' with the side seal parts 16a and 16b. In the corner part (the left corner part in the figure), there is a narrow spout part 20 with a tapered shape and a narrow width that faces diagonally outward and upward, the outer periphery of which is heat-sealed with a spout seal part 17, and a notch on both sides of the spout part 20. It is provided with portions 19a and 19b in a protruding shape.

At the opening position on the tip side of the spout portion 20, a half-cut line 21 and a notch 22 at the end above the half-cut line serve as easy-opening means.
Incidentally, the portion of the upper part of the pouch 100 where the pouring outlet 20 is not provided is heat-sealed with the upper seal portion 18. Since this portion is used as the filling port for the contents, it is left as an unsealed opening before filling with the contents, and is heat-sealed after filling with the contents.
In addition, although the half-cut lines 21 are shown as three parallel half-cut lines in the figure, they may be one or two, or multiple half-cut lines, such as one to three on each side of a central half-cut line, may be parallel to the central half-cut line, or may converge to the central half-cut line, or may be a combination of multiple parallel half-cut lines and diagonal half-cut lines that diagonally intersect the parallel half-cut lines, or may be any other shape.

The present invention can further have the following aspects.
1. A laminate for a hand-cut open package, comprising at least a base layer, an adhesive resin layer, a barrier layer, and a sealant layer, laminated in this order,
The adhesive resin layer contains low-density polyethylene,
The barrier layer and the sealant layer are adjacent to each other directly or via an anchor coat layer,
the sealant layer is an outermost layer on one surface of the laminate, and contains linear low-density polyethylene and low-density polyethylene;
The low-density polyethylene contains plant-derived low-density polyethylene,
A laminate for use in a hand-tearable package, characterized in that the mass ratio of said low-density polyethylene to said linear low-density polyethylene is 3/7 or more and 7/3 or less.
2. The laminate according to claim 1, wherein the adhesive resin layer contains a plant-derived low-density polyethylene.
3. The sealant layer has a multi-layer structure of two or more layers,
a first sealant layer which is an outermost surface layer of the sealant layers, comprising a linear low density polyethylene derived from a fossil fuel;
a second sealant layer adjacent to the first sealant layer comprising a vegetable-derived low density polyethylene;
The thickness ratio of the second sealant layer/the first sealant layer is 3/7 or more and 7/3 or less.
3. The laminate according to claim 1 or 2.
4. The laminate according to claim 3, wherein the sealant layer has a two-layer structure consisting of a first sealant layer and a second sealant layer adjacent to the barrier layer.
5. The laminate according to any one of the above 1 to 4, wherein the adhesive resin layer and the barrier layer are adjacent to each other.
6. The laminate according to any one of 1 to 5 above, wherein the sealant layer has a total thickness of 25 μm or more and 40 μm or less.
7. The laminate according to any one of 1 to 6 above, wherein the total thickness of the adhesive resin layer and the sealant layer is 50 μm or more and 90 μm or less.
8. The laminate according to any one of 1 to 7 above, wherein the barrier layer is one or more selected from the group consisting of metal foils, metal vapor deposition films, and metal oxide films.
9. The laminate according to any one of 1 to 8 above, wherein the barrier layer is a metal foil.
10. The laminate according to any one of 1 to 9 above, wherein the base layer includes a resin film.
11. The laminate according to any one of 1 to 10 above, wherein the base layer includes a resin film made of polyester.
12. The laminate according to any one of 1 to 11 above, wherein the base layer contains a resin film made of recycled polyester or plant-derived polyester.
13. The laminate has a half-cut line for manual opening,
The half-cut line is formed so as to penetrate the base material layer and not to penetrate the barrier layer and the sealant layer.
13. A laminate according to any one of 1 to 12 above.
14. The laminate has a set of marks for manual tearing,
The group of scars is formed so as to penetrate the base layer and not to penetrate the barrier layer and the sealant layer.
14. A laminate according to any one of 1 to 13 above.
15. A packaging material, characterized in that it is made from the laminate according to any one of 1 to 14 above.
16. A packaging body, characterized in that it is made from the packaging material described in 15 above.
17. A packaging bag, characterized in that it is made from the packaging material described in 15 above.

The present invention will be described more specifically below with reference to examples and comparative examples.

The raw materials used in the examples are as follows.
- Plant-derived ethylene glycol 1: Manufactured by India Glycol. 100% biomass.
・Fossil fuel-derived LDPE 1: High-pressure low-density polyethylene manufactured by Ube Maruzen Polyethylene Co., Ltd., UBE polyethylene F224N. Density 0.924g/cm3, MFR 2.0g/10min.
- Plant-derived LDPE1: SEB853 manufactured by Braskem. Density 0.923g/cm3, MFR 2.7g/10min.
- Aluminum foil 1: A1N30H-O manufactured by Nippon Seifuku Co., Ltd. Thickness: 7μm.
- Plant-derived LDPE2: SBC818 manufactured by Braskem. Density 0.918kg/m3, MFR 8.1g/10min.
- Fossil fuel-derived LLDPE 1: UZ2010L manufactured by Prime Polymer Co., Ltd. Fossil fuel derived C4LLDPE which is a copolymer of ethylene and 1-butene using a Ziegler-Natta catalyst. Density 0.922g/cm3, MFR 2.2g/10min.

[Preparation of plant-derived PET film 1]
A film was produced using plant-derived polyethylene terephthalate (PET) synthesized from fossil fuel-derived terephthalic acid and plant-derived ethylene glycol 1, and biaxially stretched to obtain a 12 μm-thick plant-derived PET film 1. The biomass ratio based on radiocarbon ( ¹⁴ C) measurement was 13%.

[Example 1]
A fossil fuel-derived LDPE 1 serving as an adhesive resin layer was melt-extruded onto a plant-derived PET film 1 serving as a base layer, while simultaneously placing an aluminum foil 1 serving as a barrier layer on the fossil fuel-derived LDPE 1 and sandwiching the aluminum foil between rolls to form a sandwich laminate.
Then, the plant-derived PE 1 and the fossil fuel-derived LLDPE 1 were co-extruded as a sealant layer on the surface of the aluminum foil 1 and passed through a roll to obtain a laminate. Various evaluations were then performed. The results are shown in Table 1.
The layer structure of the laminate is as follows:
Plant-derived PET film 1 (12 μm) / fossil fuel-derived LDPE 1 (20 μm) / aluminum foil 1 (7 μm) / plant-derived PE 1 (10.5 μm) / fossil fuel-derived LLDPE 1 (24.5 μm)

[Examples 2 to 6, Comparative Example 1]
A laminate was obtained in the same manner as in Example 1, except that the composition and thickness of the adhesive resin layer and sealant layer were changed to those listed in Table 1, and evaluated in the same manner.
In Example 6, a resin obtained by melting and mixing fossil fuel-derived LDPE 1 and plant-derived LDPE 1 at a mass ratio of 1/1 was used for the adhesive resin layer.

<Summary of evaluation results>
The laminates of all the Examples showed an excellent balance of bag rupture resistance, ease of opening by hand, and suitability for filling, but the laminate of Comparative Example 1 showed poor bag rupture resistance and suitability for filling.

<Evaluation method>

[Bag tear resistance]
Each of the 10 pouches was filled with 360 ml of water and dropped vertically (bottom down) 10 times and horizontally (surface down) 10 times from a height of 1.2 m, and the presence or absence of bag breakage and seal recession, especially at the cut and scar areas, was checked. Evaluation was performed at room temperature (25°C) and low temperature (3°C). The meaning of the results is as follows:
Evaluation criteria: .circle-solid.: No bag breakage or seal recession was observed.
○: Seal recession was observed very rarely.
△: Seal recession was observed.
×: Bag breakage was observed.

[Manual opening and sealability]
Ten pouches were opened from the notch along the half-cut line, and the presence or absence of any snags and stretch of the sealant film at the start of opening was checked. Five people divided the evaluation into two parts each.
Judgment Criteria ◎: Initial opening is smooth, with no catching or stretching of the sealant ○: Compared to ◎, there is slight catching or a slight stretching of the sealant.
△: There is a catch or there is expansion of the sealant.
×: Initial opening is difficult, there is severe catching or sealant stretching

[Filling suitability]
[Easy to open by hand]
The 10 pouches were filled with liquid contents and sealed, and the presence or absence of breakage of the pouches was visually checked.
Evaluation criteria: .circle-solid.: No breakage of the bag was observed.
×: Bag breakage was observed.

1 Laminate 2 Base material layer 3 Adhesive resin layer 4 Barrier layer 5 Sealant layer 6 Resin film 7 Anchor coat layer 11, 11' Wall film 12 Bottom film folded portion 13a, 13b Bottom film cutout portion 14 Gusset portion 15 Bottom seal portion 16a, 16b Side seal portion 17 Spout outlet seal portion 18 Top seal portion 19a, 19b Cutout portion 20 Spout outlet portion 21 Half cut line 22 Notch 100 Refill packaging bag (pouch)

Claims (9)

A laminate for a hand-cut and sealed package, comprising at least a base material layer, an adhesive resin layer, a barrier layer, and a sealant layer, which are laminated in this order,
The adhesive resin layer contains low density polyethylene,
The barrier layer and the sealant layer are adjacent to each other directly or via an anchor coat layer,
The base material layer is made of a laminated film of one or more selected from polyester film, polypropylene film, and synthetic paper,
The barrier layer is one or more selected from the group consisting of metal foil, metal vapor deposition film, and metal oxide film,
The sealant layer is the outermost layer on one side of the laminate,
The sealant layer includes a first sealant layer that is the outermost surface layer in the sealant layer;
It has a two-layer structure consisting only of the first sealant layer and an adjacent second sealant layer,
The first sealant layer is fossil fuel-derived linear low-density polyethylene,
The second sealant layer is a plant-derived low density polyethylene,
The thickness ratio of the second sealant layer/the first sealant layer is 1/1 or more and 7/3 or less,
The total thickness of the sealant layer is 25 μm or more and 40 μm or less,
A laminate for a hand-cut and sealed package, characterized in that: The laminate according to claim 1, characterized in that the adhesive resin layer contains plant-derived low-density polyethylene. The laminate according to claim 1 or 2, characterized in that the adhesive resin layer and the barrier layer are adjacent to each other. The laminate according to any one of claims 1 to 3, characterized in that the base layer contains a resin film made of recycled polyester or plant-derived polyester. The laminate has a half-cut line for manual opening,
The half-cut line is formed so as to penetrate the base material layer and not to penetrate the barrier layer and the sealant layer.
The laminate according to any one of claims 1 to 4. The laminate has a set of manual tear-opening marks;
The group of scars is formed so as to penetrate the base layer and not to penetrate the barrier layer and the sealant layer.
The laminate according to any one of claims 1 to 5. The content of C4 linear low density polyethylene in the entire sealant layer is 45% by mass or more and 70% by mass or less,
The laminate according to any one of claims 1 to 6. The linear low density polyethylene is synthesized using a Ziegler-Natta catalyst,
The laminate according to any one of claims 1 to 7. A packaging bag produced using a packaging material produced from the laminate according to any one of claims 1 to 8.

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