JP7725052B2 - Laminate, laminate manufacturing method, container, and container manufacturing method - Google Patents

Description

The present invention relates to a laminate, a method for manufacturing a laminate, a container, a method for manufacturing a container, and a composition.

In order to reduce the proportion of petroleum-derived raw materials contained in container and packaging materials, various technologies have been proposed for blending inorganic fillers with these raw materials. For example, Patent Document 1 below discloses a thermoforming sheet that satisfies specific requirements and is formed by extrusion molding a composite material consisting of an inorganic filler whose main component is talc, a polypropylene-based resin, high-density polyethylene, and an ethylene-containing auxiliary polymer, as well as a talc container for food packaging formed from the thermoforming sheet. Patent Document 2 below discloses a multi-layer hollow container that contains 50 to 80% by weight of an inorganic filler, at least one layer of which is a composition consisting of 60 to 90% by weight of the inorganic filler and 40 to 10% by weight of a specific polyethylene, and that satisfies specific requirements.

Japanese Patent Application Laid-Open No. 2000-127237 JP 2014-162495 A

While increasing the proportion of inorganic filler in the container material is expected to improve the rigidity of the container, it may also result in a decrease in tear resistance and impact resistance. Therefore, there is a demand for a laminate that contains an inorganic filler and has good tear resistance, impact resistance, and rigidity when formed into a container shape.
Therefore, a main object of the present invention is to provide a laminate that contains an inorganic filler and has good tear resistance, impact resistance, and rigidity.

That is, the present invention provides:
a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer;
the first outer layer is made of a first resin composition containing a first polyolefin-based resin,
the second outer layer is made of a second resin composition containing a second polyolefin-based resin,
The present invention provides a laminate in which the intermediate layer is made of a third composition containing talc, an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, and the talc content exceeds 50% by mass.
The content of the ethylene/α-olefin copolymer in the third composition may be 1% by mass or more and 30% by mass or less.
The ethylene/α-olefin interpolymer contained in the third composition may be a metallocene-based ethylene/α-olefin interpolymer.
The third polyolefin resin may include block polypropylene.
The first resin composition and/or the second resin composition may further contain an inorganic filler.
The first polyolefin resin and/or the second polyolefin resin may contain at least one selected from the group consisting of homopolypropylene, high-density polyethylene, and ethylene/α-olefin copolymer.
The first polyolefin resin and/or the second polyolefin resin may contain the homopolypropylene, and the homopolypropylene may have a tensile modulus of elasticity of 1500 MPa or more.
The first polyolefin resin and/or the second polyolefin resin may contain the homopolypropylene, and the homopolypropylene may have a tensile modulus of elasticity of 1700 MPa or more.
The first polyolefin resin and/or the second polyolefin resin may include a combination of the homopolypropylene and the ethylene/α-olefin copolymer, and the homopolypropylene may have a tensile modulus of elasticity of 1700 MPa or more.
The present invention also provides a container formed using the laminate.
The expansion ratio of the container may be 2.0 or more.
The present invention provides
a first resin composition containing a first polyolefin-based resin;
a second resin composition containing a second polyolefin-based resin;
a third composition comprising talc, an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, wherein the talc content is more than 50% by mass; and
Using
a first outer layer made of the first resin composition;
a second outer layer made of the second resin composition; and
and an intermediate layer disposed between the first outer layer and the second outer layer and comprising the third composition.
The present invention provides
a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer;
the first outer layer is made of a first resin composition containing a first polyolefin-based resin,
the second outer layer is made of a second resin composition containing a second polyolefin-based resin,
the intermediate layer is made of a third composition containing talc, an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, and the talc content is more than 50% by mass;
The laminate
Also provided is a method for manufacturing a container, which includes molding with a solid state molding machine.
In the solid-phase molding machine, the amount of power consumed per unit volume of the laminate during molding of the container may be 90% or less of the amount of power consumed when the talc content in the third composition is 0 mass%.
The present invention provides
The present invention also provides a composition comprising talc, an ethylene/α-olefin copolymer, and a polyolefin resin other than the ethylene/α-olefin copolymer, wherein the content of the talc is more than 50% by mass.
The composition may be a container material.
The present invention provides
a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer;
the first outer layer is made of a first resin composition containing a first polyolefin-based resin,
the second outer layer is made of a second resin composition containing a second polyolefin-based resin,
The present invention also provides a laminate in which the intermediate layer is made of a third composition comprising an inorganic filler, an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, and the content of the inorganic filler is more than 50 mass%.

The present invention provides a laminate that contains an inorganic filler and can be used to produce a container that has excellent tear resistance, impact resistance (particularly cold impact resistance, which is impact resistance at low temperatures), and rigidity. Note that the effects of the present invention are not limited to those described herein, and may be any of the effects described within this specification.

FIG. 2 is a perspective view showing an example of a testing machine used in an evaluation test of cold impact resistance. FIG. 1 is a front view showing a testing machine when a weight is dropped in a cold-shock resistance evaluation test.

Preferred embodiments for implementing the present invention are described below. The embodiments described below are representative embodiments of the present invention, and the scope of the present invention is not limited to these embodiments.

1. Laminated body

A laminate according to one embodiment of the present invention has a first outer layer, a second outer layer, and an intermediate layer disposed between the first and second outer layers. The layer structure, shape, uses, and manufacturing method of the laminate will be described below.

1-1. Layer structure of laminate

1-1-1. First outer layer

The first outer layer is made of a first resin composition containing a first polyolefin-based resin. In this specification, a polyolefin-based resin is a polymer having 50 mol% or more of olefin-derived structural units out of 100 mol% of all structural units. The first polyolefin-based resin is made of one or a combination of two or more polyolefin-based resins.

The polyolefin-based resins include, for example, olefin homopolymers and copolymers of olefins and other monomers. The copolymers of olefins and other monomers may be, for example, block copolymers or random copolymers. The olefin is preferably an α-olefin, more preferably propylene and ethylene. That is, the polyolefin-based resin is preferably a polyα-olefin-based resin, more preferably a polypropylene-based resin or a polyethylene-based resin.

Examples of the polypropylene-based resin include propylene homopolymers (homopolypropylenes) and copolymers of propylene and other monomers. The copolymers of propylene and other monomers may be, for example, block copolymers (block polypropylenes) or random copolymers (random polypropylenes).

Examples of the polyethylene resin include ethylene homopolymers and copolymers of ethylene and other monomers. The copolymer of ethylene and other monomers is preferably an ethylene/α-olefin copolymer. The types and properties of the ethylene/α-olefin copolymer are described below in "1-1-3. Intermediate Layer." That is, the description of the ethylene/α-olefin copolymer contained in the intermediate layer also applies to the ethylene/α-olefin copolymer contained in the first resin composition. However, the type and properties of the ethylene/α-olefin copolymer contained in the first resin composition may differ from the type and properties of the ethylene/α-olefin copolymer contained in the intermediate layer described below. The ethylene/α-olefin copolymer contained in the first resin composition is preferably a metallocene-based ethylene/α-olefin copolymer. The description of the metallocene-based ethylene/α-olefin copolymer is also described below in "1-1-3. Intermediate Layer."

Examples of the polyethylene resins include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), and linear low density polyethylene (LLDPE).

The first polyolefin resin contained in the first resin composition is preferably one or a combination of two or more poly-α-olefin resins, more preferably one or a combination of two or more selected from polypropylene resins and polyethylene resins. The first polyolefin resin more preferably contains at least one selected from the group consisting of homopolypropylene, high-density polyethylene, and ethylene/α-olefin copolymer. The first polyolefin resin particularly preferably contains homopolypropylene, a combination of homopolypropylene and high-density polyethylene, or a combination of homopolypropylene and ethylene/α-olefin copolymer. The combination of homopolypropylene and ethylene/α-olefin copolymer is particularly preferably a combination of homopolypropylene and metallocene-based ethylene/α-olefin copolymer. The inclusion of such a first polyolefin resin can improve the extensibility of the laminate during molding and processing.

When the first polyolefin resin includes homopolypropylene, the density of the homopolypropylene may be, for example, 0.880 g/cm ³ or more and 0.920 g/cm ³ or less, 0.885 g/cm ³ or more and 0.915 g/cm ³ or less, or 0.890 g/cm ³ or more and 0.910 g/cm ³ or less.

When the first polyolefin resin contains homopolypropylene, the melt flow rate (MFR) of the homopolypropylene may be, for example, 0.1 g/10 min or more and 5.0 g/10 min or less, 0.2 g/10 min or more and 4.0 g/10 min or less, 0.3 g/10 min or more and 3.5 g/10 min or less, 0.3 g/10 min or more and 2.5 g/10 min or less, or 0.4 g/10 min or more and 2.0 g/10 min or less. The MFR of the homopolypropylene is a value measured under conditions of a temperature of 230°C and a load of 2.16 kg.

When the first polyolefin resin contains homopolypropylene, the lower limit of the tensile modulus of the homopolypropylene is, for example, 1400 MPa or more, preferably 1500 MPa or more, and more preferably 1600 MPa or more. Having the tensile modulus within this range can contribute to improving the rigidity of the laminate. The upper limit of the tensile modulus may be, for example, 2600 MPa or less, 2500 MPa or less, or 2400 MPa or less. When the first polyolefin resin contains a combination of homopolypropylene and an ethylene/α-olefin copolymer (particularly a combination of homopolypropylene and a metallocene-based ethylene/α-olefin copolymer), the tensile modulus of the homopolypropylene is preferably high, preferably 1700 MPa or more, more preferably 1800 MPa or more, even more preferably 1900 MPa or more, and particularly preferably 2000 MPa or more. In this way, using a combination of homopolypropylene, which has a high tensile modulus, and ethylene/α-olefin copolymer is preferable for obtaining a laminate with good tear resistance, impact resistance (particularly cold impact resistance, which is impact resistance at low temperatures), and rigidity. The tensile modulus of the homopolypropylene is a value measured in accordance with JIS K7161-1:2014.

When the first polyolefin resin contains high-density polyethylene, the density of the high-density polyethylene may be, for example, 0.940 g/cm ³ or more and 0.980 g/cm ³ or less, 0.945 g/cm ³ or more and 0.975 g/cm ³ or less, or 0.950 g/cm ³ or more and 0.970 g/cm ³ or less.

When the first polyolefin resin contains high-density polyethylene, the MFR of the high-density polyethylene may be, for example, 0.1 g/10 min or more and 2.0 g/10 min or less, 0.1 g/10 min or more and 1.0 g/10 min or less, 0.1 g/10 min or more and 0.5 g/10 min or less, or 0.2 g/10 min or more and 0.4 g/10 min or less. The MFR of the high-density polyethylene is a value measured under conditions of a temperature of 190°C and a load of 2.16 kg.

When the first polyolefin resin contains a combination of homopolypropylene and high-density polyethylene, the mass ratio of the homopolypropylene to the high-density polyethylene contained in the first polyolefin resin (homopolypropylene:high-density polyethylene) may be adjusted within the range of, for example, 50:50 to less than 100:0, but is not particularly limited.

When the first polyolefin resin contains a combination of homopolypropylene and ethylene/α-olefin copolymer, the mass ratio of homopolypropylene to ethylene/α-olefin copolymer (homopolypropylene:ethylene/α-olefin copolymer) contained in the first polyolefin resin is preferably 99.5:0.5 to 50:50, more preferably 99:1 to 60:40, and even more preferably 95:5 to 70:30.

The one or more polyolefin-based resins that make up the first polyolefin-based resin may be petroleum-derived or biomass-derived, or may be a combination of petroleum-derived and biomass-derived resins. Including a biomass-derived polyolefin-based resin in the first polyolefin-based resin can contribute to reducing the amount of petroleum-derived raw materials in the laminate.

The first resin composition may contain components other than the first polyolefin-based resin. These components may be included in the first resin composition to the extent that the effects of the present invention are not impaired. These components may be, for example, inorganic fillers. That is, the first resin composition may further contain an inorganic filler. This may reduce the proportion of petroleum-derived raw materials contained in the laminate. Furthermore, the first resin composition may not contain any components other than the first polyolefin-based resin. That is, the first resin composition may consist of the first polyolefin-based resin.

1-1-2. Second outer layer

The second outer layer is made of a second resin composition containing a second polyolefin-based resin. The second polyolefin-based resin is made of one or a combination of two or more polyolefin-based resins. Examples of such polyolefin-based resins are described above in "1-1-1. First Outer Layer." In other words, the explanation regarding the first polyolefin-based resin also applies to the second polyolefin-based resin.

The second polyolefin resin contained in the second resin composition is preferably one or a combination of two or more poly-α-olefin resins, more preferably one or a combination of two or more selected from polypropylene resins and polyethylene resins. The second polyolefin resin more preferably contains at least one selected from the group consisting of homopolypropylene, high-density polyethylene, and ethylene/α-olefin copolymer. The second polyolefin resin particularly preferably contains homopolypropylene, a combination of homopolypropylene and high-density polyethylene, or a combination of homopolypropylene and ethylene/α-olefin copolymer. The combination of homopolypropylene and ethylene/α-olefin copolymer is particularly preferably a combination of homopolypropylene and metallocene-based ethylene/α-olefin copolymer. The inclusion of such a second polyolefin resin can improve the extensibility of the laminate during molding and processing.

Examples of the properties and mass ratios of the homopolypropylene and high-density polyethylene in the second polyolefin resin may be as described above in "1-1-1. First Outer Layer." The ethylene/α-olefin copolymer in the second polyolefin resin may also be as described above in "1-1-1. First Outer Layer."

The one or more polyolefin-based resins that make up the second polyolefin-based resin may be petroleum-derived or biomass-derived, or may be a combination of petroleum-derived and biomass-derived resins. Including a biomass-derived polyolefin-based resin in the second polyolefin-based resin can contribute to reducing the amount of petroleum-derived raw materials in the laminate.

The second resin composition may contain components other than the second polyolefin-based resin. These components may be included in the second resin composition to the extent that the effects of the present invention are not impaired. These components may be, for example, inorganic fillers. That is, the second resin composition may further contain an inorganic filler. This may reduce the proportion of petroleum-derived raw materials contained in the laminate. Furthermore, the second resin composition may not contain any components other than the second polyolefin-based resin. That is, the second resin composition may consist of the second polyolefin-based resin.

The one or more resins contained in the second polyolefin resin may be entirely the same as, or partially or entirely different from, the one or more resins contained in the first polyolefin resin. That is, the second polyolefin resin may be the same as or different from the first polyolefin resin. Furthermore, the composition of the second resin composition containing the second polyolefin resin may be the same as or different from the composition of the first resin composition containing the first polyolefin resin. That is, the composition of the second outer layer may be the same as or different from the first composition.

In the laminate of this embodiment, the first polyolefin resin and the second polyolefin resin are preferably the same, the first resin composition and the second resin composition preferably have the same composition, and the first outer layer and the second outer layer preferably have the same composition. Sharing the raw materials for the first and second outer layers in this way can contribute to simplifying the manufacturing process of the laminate or reducing manufacturing costs.

1-1-3. Middle class

The intermediate layer is made of a third composition containing an inorganic filler, an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, with the inorganic filler content exceeding 50% by mass.

Examples of the inorganic filler include talc, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium silicate, magnesium silicate, calcium sulfate, barium sulfate, calcium sulfite, titanium dioxide, silicon dioxide, glass, clay, and diatomaceous earth. The inorganic filler contained in the third composition may be, for example, one or a combination of two or more of these inorganic fillers, and is preferably talc and/or calcium carbonate, and more preferably talc.

The inorganic filler content in the third composition is greater than 50% by mass, preferably greater than 51% by mass, and more preferably greater than 55% by mass. Such a high inorganic filler content improves the rigidity of the laminate and reduces the proportion of petroleum-derived raw materials contained in the laminate. The inorganic filler content is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. Setting the inorganic filler content at this upper limit improves the extensibility of the laminate during molding. A preferred range for the inorganic filler content may be a combination selected from the lower and upper limits described above, and is preferably greater than 50% by mass but less than 80% by mass, more preferably 51% by mass or more but less than 80% by mass, even more preferably 55% by mass or more but less than 80% by mass, and particularly preferably 55% by mass or more but less than 75% by mass, or 55% by mass or more but less than 70% by mass.

The ethylene/α-olefin copolymer contained in the third composition is a copolymer of ethylene and an α-olefin. The ethylene/α-olefin copolymer contained in the third composition is preferably a metallocene-based ethylene/α-olefin copolymer. The metallocene-based ethylene/α-olefin copolymer is a copolymer produced by polymerizing ethylene and an α-olefin in the presence of a metallocene catalyst. The metallocene-based ethylene/α-olefin copolymer is preferably a metallocene-based plastomer. In this specification, the metallocene-based plastomer is a metallocene-based ethylene/α-olefin copolymer having a density lower than that of very low-density polyethylene resin (VLDPE). The density of the metallocene-based plastomer may be, for example, 0.920 g/cm ³ or less. When a commercially available product is used as the metallocene-based plastomer, the product may be selected from, for example, "Yumerit" manufactured by Ube Maruzen Polyethylene Co., Ltd., "Evolue" manufactured by Prime Polymer Co., Ltd., and "Kernel" and "Harmolex" manufactured by Japan Polyethylene Corporation.

The density of the ethylene/α-olefin copolymer is preferably 0.870 g/cm ^{or more} , more preferably 0.880 g/cm ^{or more} , even more preferably 0.890 g/cm ^or more, and particularly preferably 0.900 g/cm or ^more . The density is preferably 0.920 g/cm ^{or less} , more preferably 0.915 g/cm ^or less, and even more preferably 0.910 g/cm ^{or less} . A preferred numerical range for the density may be a combination selected from the lower and upper limits described above, and is preferably 0.870 g/cm or ^{more and} 0.920 g/cm ^or less, more preferably 0.880 g/cm ^{or more} and 0.915 g/cm ^{or less} , even more preferably 0.890 g/cm ^{or more} and 0.915 g/cm ^{or less} , and particularly preferably 0.890 g/cm ^{or more and} 0.910 g/cm or ^less , or 0.900 g/cm or more and 0.910 g/cm ^{or less} . A density within this numerical range is preferred for obtaining a laminate having good tear resistance, impact resistance (particularly cold impact resistance, which is impact resistance at low temperatures), and rigidity. The density of the ethylene/α-olefin copolymer is a value measured in accordance with JIS K7112:1999.

The MFR of the ethylene/α-olefin copolymer is preferably 1.0 g/10 min or more, more preferably 1.5 g/10 min or more, even more preferably 1.8 g/10 min or more, and particularly preferably 2.0 g/10 min or more, or 2.1 g/10 min or more. The MFR is preferably 3.5 g/10 min or less, more preferably 3.0 g/10 min or less, even more preferably 2.5 g/10 min or less, and particularly preferably 2.3 g/10 min or less. A preferred numerical range of the MFR may be a combination selected from the above-mentioned lower and upper limits, and is preferably 1.0 g/10 min to 3.5 g/10 min, more preferably 1.5 g/10 min to 3.5 g/10 min, even more preferably 1.8 g/10 min to 3.5 g/10 min, particularly preferably 2.0 g/10 min to 3.5 g/10 min, 2.1 g/10 min to 3.5 g/10 min, 2.1 g/10 min to 3.0 g/10 min, 2.1 g/10 min to 2.5 g/10 min, or 2.1 g/10 min to 2.3 g/10 min. An MFR within such a numerical range is preferred to obtain a laminate having good tear resistance, impact resistance (particularly cold impact resistance), and rigidity. The MFR of the above ethylene/α-olefin copolymer is a value measured in accordance with JIS K6922-2:2018 under conditions of a temperature of 190°C and a load of 2.16 kg.

The third composition contains a third polyolefin resin other than the ethylene/α-olefin copolymer (hereinafter simply referred to as the "third polyolefin resin"). Examples of this polyolefin resin may be as described above in "1-1-1. First Outer Layer."

The third polyolefin resin contained in the third composition is preferably one or a combination of two or more poly-α-olefin resins, and more preferably one or a combination of two or more polypropylene resins. The third polyolefin resin particularly preferably contains block polypropylene. When the third polyolefin resin contains block polypropylene, the third polyolefin resin may further contain homopolypropylene. That is, the third polyolefin resin preferably contains a combination of block polypropylene and homopolypropylene.

When the third polyolefin resin contains a block polypropylene, the density of the block polypropylene is preferably 0.880 g/cm or ^more , more preferably 0.885 g/cm ^{or more} , even more preferably 0.890 g/cm or ^more , particularly preferably 0.892 g/cm ^{or more} , or 0.895 g/cm or ^more . The density is preferably 0.920 g/cm or ^less , more preferably 0.915 g/cm ^{or less} , even more preferably 0.913 g/cm ^or less, particularly preferably 0.910 g/cm ^or less. A preferred numerical range for the density may be a combination selected from the above-mentioned lower limit and upper limit, and is preferably 0.880 g/ ^cm3 or more and 0.920 g/ ^cm3 or less, more preferably 0.885 g/ ^cm3 or more and 0.915 g/cm3 or ^less , even more preferably 0.890 g/ ^cm3 or more and 0.915 g/cm3 or ^less , and particularly preferably 0.892 g/ ^cm3 or more and 0.913 g/cm3 or ^less , or 0.895 g/ ^cm3 or more and 0.910 g/cm3 or ^less .

When the third polyolefin resin contains a block polypropylene, the MFR of the block polypropylene is preferably 0.1 g/10 min or more, more preferably 0.2 g/10 min or more, and even more preferably 0.3 g/10 min or more. The MFR is preferably 2.0 g/10 min or less, more preferably 1.5 g/10 min or less, even more preferably 1.0 g/10 min or less, and particularly preferably 0.8 g/10 min or less, 0.6 g/10 min or less, or 0.5 g/10 min or less. A preferred numerical range for the MFR may be a combination selected from the lower and upper limits described above, and is preferably 0.1 g/10 min or more and 2.0 g/10 min or less, more preferably 0.1 g/10 min or more and 1.5 g/10 min or less, even more preferably 0.1 g/10 min or more and 1.0 g/10 min or less, and particularly preferably 0.1 g/10 min or more and 0.8 g/10 min or less, 0.2 g/10 min or more and 0.6 g/10 min or less, or 0.3 g/10 min or more and 0.5 g/10 min or less. The MFR of the block polypropylene is a value measured at a temperature of 230°C and a load of 2.16 kg.

When the third polyolefin resin contains a combination of block polypropylene and homopolypropylene, the homopolypropylene preferably has a high tensile modulus, preferably 1700 MPa or more, more preferably 1800 MPa or more, even more preferably 1900 MPa or more, and particularly preferably 2000 MPa or more. In this way, by combining block polypropylene with homopolypropylene, which has a high tensile modulus, the rigidity of the laminate can be improved.

The third composition may contain components other than the inorganic filler, ethylene/α-olefin copolymer, and third polyolefin resin. Examples of such components include resins other than the ethylene/α-olefin copolymer and third polyolefin resin, and additives. The third composition preferably does not contain components other than the inorganic filler, ethylene/α-olefin copolymer, and third polyolefin resin; that is, it preferably consists of the inorganic filler, ethylene/α-olefin copolymer, and third polyolefin resin.

In the third composition, the total content of the ethylene/α-olefin copolymer and the third polyolefin resin is less than 50% by mass, preferably 49% by mass or less, and more preferably 45% by mass or less. The total content of the ethylene/α-olefin copolymer and the third polyolefin resin is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. A preferred range for this total content may be a combination selected from the lower and upper limits described above, and is preferably 20% by mass or more but less than 50% by mass, more preferably 20% by mass or more but 49% by mass or less, even more preferably 20% by mass or more but 45% by mass or less, and particularly preferably 25% by mass or more but 45% by mass or less, or 30% by mass or more but 45% by mass or less.

The content of the ethylene/α-olefin copolymer in the third composition is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 4% by mass or more. At such a lower limit, the tear resistance and impact resistance (particularly cold impact resistance) of the laminate can be improved. The content of the ethylene/α-olefin copolymer in the third composition is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 11% by mass or less. At such an upper limit, a decrease in the rigidity of the laminate can be prevented. A preferred numerical range for the content of the ethylene/α-olefin copolymer may be a combination selected from the lower and upper limits described above, and is preferably 1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 20% by mass or less, even more preferably 1% by mass or more and 15% by mass or less, particularly preferably 2% by mass or more and 15% by mass or less, 3% by mass or more and 15% by mass or less, or 4% by mass or more and 11% by mass or less. By ensuring that the content of the ethylene/α-olefin copolymer is within the above range, a laminate with a better balance of tear resistance, impact resistance (particularly cold impact resistance), and rigidity can be obtained.

In general, layers with a high inorganic filler content tend to have lower impact resistance, tear resistance, and extensibility during molding. Specifically, the impact resistance and tear resistance of a layer with a high inorganic filler content may be lower than that of a layer without inorganic filler. Furthermore, the extensibility of a layer with a high inorganic filler content during molding may be lower than that of a layer without inorganic filler, which may result in holes being formed in the layer or uneven layer thickness during molding. On the other hand, the laminate of this embodiment has good impact resistance, tear resistance, and extensibility during molding, despite having an intermediate layer with a high inorganic filler content of over 50% by mass. Specifically, the laminate of this embodiment has good impact resistance because the intermediate layer contains an ethylene/α-olefin copolymer and a third polyolefin resin. Furthermore, the laminate of this embodiment has first and second outer layers on the outside of the intermediate layer, resulting in good tear resistance and good extensibility during molding.

In the laminate of this embodiment, the third composition, which has a high inorganic filler content, improves the rigidity of the laminate and can also contribute to reducing the amount of petroleum-derived materials in the laminate. Therefore, the present invention can also provide the composition containing more than 50% by mass of an inorganic filler (e.g., talc). That is, the present invention can also provide a composition containing an inorganic filler (e.g., talc), an ethylene/α-olefin copolymer, and a polyolefin resin other than the ethylene/α-olefin copolymer, and having a content of the inorganic filler (e.g., talc) of more than 50% by mass. The composition according to one embodiment of the present invention may be, in particular, a laminate material, i.e., a laminate composition. Furthermore, the laminate may be used for a container, as described below. Therefore, the composition may be, in particular, a container material, i.e., a container composition. Details of the container are as described below in "2. Container," and the composition may be used to form the container described below in "2. Container."

1-1-4. Other layers

The laminate of this embodiment only needs to have a first outer layer, a second outer layer, and an intermediate layer disposed between the first outer layer and the second outer layer, and may also have one or more other layers. The one or more other layers may be located either outside or inside the first outer layer and/or the second outer layer. The laminate may also not include the other layers. In other words, the laminate may consist of a first outer layer, a second outer layer, and an intermediate layer disposed between the first outer layer and the second outer layer.

1-2. Laminate shape

The laminate according to this embodiment is preferably in the form of a sheet or film. That is, the laminate is preferably a sheet or film. The thickness of the sheet may be, for example, 0.2 mm or more and 2.5 mm or less, 0.3 mm or more and 2.2 mm or less, or 0.5 mm or more and 2.0 mm or less. The thickness of the film may be, for example, 10 μm or more and 200 μm or less.

As described below, the present invention also provides a container formed using the laminate. In other words, the shape of the laminate may be the shape of a container.

1-3. Uses of laminates

The laminate of this embodiment has good tear resistance, impact resistance (particularly cold impact resistance), and rigidity when formed into a container. Therefore, this laminate may be used to form a container, i.e., it may be intended for use as a container. Details of this container are as described below in "2. Container," and the laminate of this embodiment can be used to form the container described below in "2. Container."

1-4. Laminate manufacturing method

The laminate of this embodiment is produced using the first resin composition, the second resin composition, and the third composition. That is, the present invention also provides a method for producing a laminate, using a first resin composition containing a first polyolefin resin, a second resin composition containing a second polyolefin resin, and a third composition containing an inorganic filler (e.g., talc), an ethylene/α-olefin copolymer, and a third polyolefin resin other than the ethylene/α-olefin copolymer, wherein the inorganic filler (e.g., talc) content exceeds 50% by mass, to produce a laminate having a first outer layer made of the first resin composition, a second outer layer made of the second resin composition, and an intermediate layer disposed between the first outer layer and the second outer layer and made of the third composition.

The laminate may be obtained by a manufacturing method known in the art. Examples of such manufacturing methods include coextrusion and lamination (e.g., thermal lamination and dry lamination). When using the coextrusion method, for example, the first resin composition, the second resin composition, and the third composition are each placed in separate extruders and heated and melted, and then these melts are laminated and extruded through a multi-layer die to obtain a laminate. When using the lamination method, for example, a laminate may be obtained by bonding a first outer layer made of the first resin composition, an intermediate layer made of the third composition, and a second outer layer made of the second resin composition together using heat or an adhesive. The coextrusion method allows molding and lamination to be performed simultaneously, which may simplify the manufacturing process compared to the lamination method. Therefore, the laminate of this embodiment may be manufactured by, for example, the coextrusion method.

2. container

The above-mentioned laminate has good tear resistance, impact resistance (particularly cold impact resistance), and rigidity in the shape of a container. Therefore, the present invention also provides a container formed using the above-mentioned laminate. A container according to one embodiment of the present invention has good tear resistance, impact resistance (particularly cold impact resistance), and rigidity, similar to the above-mentioned laminate. The laminate used in the container of this embodiment is as described above in "1. Laminate," and this description also applies to this embodiment. Below, the shape, use, and manufacturing method of the container will be described in order.

2-1. Container shape

The container of this embodiment may have, for example, a bottom surface, side surfaces extending upward from the periphery of the bottom surface, and an opening surrounded by the upper end of the side surfaces. The container may further have, for example, a flange portion formed by extending outward from the opening.

In the above-mentioned container, the shape of the bottom and opening may be, for example, circular, elliptical, polygonal, or approximately polygonal, but is not particularly limited. The shapes of the bottom and opening may be the same or different. The side surfaces may be perpendicular to the bottom, or may be tapered or inverted tapered. The shape of the container having the above-mentioned bottom, side surfaces, and opening may be, for example, a cylindrical shape with a bottom or an inverted truncated cone with a bottom, but is not particularly limited.

The container of this embodiment may be, for example, a container formed by drawing using the laminate. The drawing may be, for example, deep drawing. That is, the container of this embodiment may be a deep drawn container. In this specification, a deep drawn container means a container having an expansion ratio of 2.5 or more. In this specification, the expansion ratio of a container is the ratio of the total area of the side and bottom surfaces to the area of the opening, and is a value calculated by the following formula. The larger the expansion ratio, the more deeply the container is drawn.
Container expansion ratio = (side area + bottom area) / opening area

The expansion ratio of the container may be, for example, 2.0 or more, 2.5 or more, 3.0 or more, 4.0 or more, or 5.0 or more. The laminate used for the container has good extensibility when formed into the container shape, making it possible to obtain a container with such an expansion ratio. The expansion ratio is preferably 7.0 or less, and more preferably 6.0 or less. Setting the expansion ratio at this upper limit can prevent the thickness of the side portion of the container from becoming excessively thin and unsuitable for practical use.

2-2. Container Use

As shown in the examples below, the container of this embodiment has good impact resistance at low temperatures (specifically, impact resistance at -20°C). Therefore, the container is suitable for storing the contents in a refrigerator or freezer. That is, the container may be, for example, for refrigerator storage or freezer storage, and preferably for freezer storage.

In addition, in the container of this embodiment, the intermediate layer containing the inorganic filler is present between the first outer layer and the second outer layer. Therefore, if the first and second outer layers do not contain inorganic filler, contact between the inorganic filler in the intermediate layer and the contents of the container can be prevented. Therefore, the container may contain contents that require consideration from a hygienic standpoint, such as food. That is, the container may be, for example, for food. Furthermore, since the container has good impact resistance at low temperatures, the container may be, for example, for refrigerated or frozen foods, and preferably for frozen foods.

2-3. Container manufacturing method

The container of this embodiment can be manufactured by a manufacturing method including a step of molding the laminate described above in "1. Laminate" using a solid-state molding machine. Specifically, the present invention also provides a container manufacturing method including a step of molding, using a solid-state molding machine, a laminate having a first outer layer, a second outer layer, and an intermediate layer disposed between the first and second outer layers, wherein the first outer layer is made of a first resin composition containing a first polyolefin-based resin, the second outer layer is made of a second resin composition containing a second polyolefin-based resin, and the intermediate layer is made of a third composition containing an inorganic filler (e.g., talc), an ethylene/α-olefin copolymer, and a third polyolefin-based resin other than the ethylene/α-olefin copolymer, the third composition containing the inorganic filler (e.g., talc) in an amount of more than 50% by mass.

In this specification, a solid-state molding machine refers to a machine that produces molded products by solid-state molding, which heats a laminate and molds the laminate in a non-molten (solid or semi-solid) state. Specifically, this non-molten laminate is a laminate that has been heated at a temperature lower than the melting point of the resin with the highest melting point contained in the laminate and higher than the crystallization temperature of the resin with the lowest crystallization temperature contained in the laminate. In other words, the method for manufacturing a container according to this embodiment may include the steps of heating the laminate at a temperature lower than the melting point of the resin with the highest melting point contained in the laminate and higher than the crystallization temperature of the resin with the lowest crystallization temperature contained in the laminate, and molding the heated laminate.

Compared to melt molding, which molds a molten laminate, solid-state molding produces a lower laminate temperature during molding, requiring less heat when heating the laminate. Furthermore, since the amount of heat required to heat an inorganic filler is generally the same as that required to raise the temperature to the same as that of the resin, the amount of heat required when heating a laminate containing inorganic filler in solid-state molding is less than when heating a laminate without inorganic filler. Therefore, adopting solid-state molding reduces the amount of electricity required in the manufacturing process, enabling energy savings.

In the container manufacturing method according to this embodiment, the solid-state forming method is preferably a solid-state pressure forming method. That is, the container manufacturing method preferably includes a step of molding the laminate using a solid-state pressure forming machine. As used herein, a solid-state pressure forming machine refers to a machine that produces a molded product using a solid-state pressure forming method, in which a laminate is heated, the laminate in a non-molten (solid or semi-solid) state is pressurized with compressed air, and the laminate is tightly attached to a mold for molding. The heating temperature of the laminate to obtain a non-molten laminate in the solid-state pressure forming method is the same as that of the solid-state forming method described above. Like the solid-state forming method described above, the solid-state pressure forming method enables energy savings in the manufacturing process. Because a solid-state pressure forming machine is capable of applying high pressure to the laminate, it is suitable for manufacturing deep-draw containers, which require the laminate to be deeply stretched. That is, the container manufacturing method according to this embodiment may preferably be a deep-draw container manufacturing method that includes molding the laminate using a solid-state pressure forming machine.

In the container manufacturing method according to this embodiment, the power consumption of the solid-state molding machine (particularly, a solid-state pressure molding machine) is less than the power consumption when the inorganic filler (e.g., talc) content in the third composition is 0% by mass. Specifically, in the solid-state molding machine (particularly, a solid-state pressure molding machine), the power consumption per unit volume of the laminate during molding of the container can be 90% or less of the power consumption when the inorganic filler (e.g., talc) content in the third composition is 0% by mass. The power consumption per unit volume of the laminate during molding of the container [kW·h/cm ³ ] is a value calculated by multiplying the power [kW] measured by connecting a wattmeter to the wiring of the main breaker of the solid-state molding machine (particularly, a solid-state pressure molding machine) by the time [h] required to mold 10,000 containers, to calculate the power amount [kW·h], and dividing this value by the volume [cm ³ ] of the laminate per shot. The volume [cm ³ ] of the laminate per shot is a value calculated by the thickness [cm] × width [cm] × feed [cm] of the laminate supplied to a solid-state molding machine (particularly a solid-state pressure molding machine) to mold 10,000 containers.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

(1) Test Example 1: Container Evaluation

(1-1) Manufacturing of laminated sheets and containers

A laminate sheet (laminate) and container were manufactured using the following raw materials and following the manufacturing procedure below.

a. Raw material [talc]
Nippon Talc Co., Ltd. Average particle size: 15 μm
[Homopolypropylene (A) (H-PP(A))]
MFR (temperature 230℃, load 2.16kg): 0.5g/10 minutes Density: 0.9g/cm ³
Tensile modulus: 1600 MPa
[Homopolypropylene (B) (H-PP(B))]
MFR (temperature 230℃, load 2.16kg): 1.6g/10 minutes Density: 0.9g/cm ³
Tensile modulus: 2000 MPa
[Block polypropylene (B-PP)]
MFR (temperature 230℃, load 2.16kg): 0.4g/10min Density: 0.9g/cm ³
[High density polyethylene (HDPE)]
MFR (temperature 190℃, load 2.16kg): 0.3g/10min Density: 0.96g/cm ³
[Metallocene-based ethylene/α-olefin copolymer (metallocene-based plastomer)]
MFR (temperature 190℃, load 2.16kg): 2.2g/10min Density: 0.9g/cm ³

b. Manufacturing Procedure (Example 1)
A compound masterbatch was prepared by kneading 71.2% by mass of talc and 28.8% by mass of block polypropylene using a twin-screw extruder. 100 parts by mass of this compound was blended with 9.4 parts by mass of block polypropylene and 10.8 parts by mass of a metallocene-based ethylene/α-olefin copolymer, and the blend was kneaded using a twin-screw extruder. This resulted in a third composition containing 55.9% by mass of talc, 33.3% by mass of block polypropylene, and 10.8% by mass of a metallocene-based ethylene/α-olefin copolymer. A first resin composition and a second resin composition, each consisting of 100% by mass of homopolypropylene (A), were prepared using a single-screw extruder. The first resin composition, the second resin composition, and the third composition were kneaded and extruded. This resulted in a three-layer laminate sheet having, in that order, a first outer layer made of the first resin composition, an intermediate layer made of the third composition, and a second outer layer made of the second resin composition. During the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 15 μm, the thickness of the intermediate layer was 770 μm, and the thickness of the second outer layer was 15 μm. The resulting laminate sheet had a thickness of 0.80 mm. The laminate sheet was molded by solid-state pressure molding using a solid-state pressure molding machine to obtain a container in the shape of an inverted truncated cone with a bottom. The opening of the container had a diameter (caliber) of 96 mm, a depth of 41 mm, and an expansion ratio of 2.1.

Example 2
100 parts by mass of the compound of Example 1 was blended with 13.7 parts by mass of block polypropylene and 6.5 parts by mass of metallocene-based ethylene/α-olefin copolymer and kneaded using a twin-screw extruder. This resulted in a third composition containing 55.9% by mass of talc, 37.6% by mass of block polypropylene, and 6.5% by mass of metallocene-based ethylene/α-olefin copolymer. A single-screw extruder was used to prepare a first resin composition and a second resin composition, each consisting of 50% by mass of homopolypropylene (A) and 50% by mass of high-density polyethylene. A laminate sheet and a container were then obtained using the same procedure as in Example 1. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Example 1.

Example 3
100 parts by mass of the compound of Example 1 was blended with 14.8 parts by mass of block polypropylene and 4.3 parts by mass of metallocene-based ethylene/α-olefin copolymer and kneaded using a twin-screw extruder. This resulted in a third composition containing 55.9% by mass of talc, 39.8% by mass of block polypropylene, and 4.3% by mass of metallocene-based ethylene/α-olefin copolymer. A laminate sheet was then obtained using the same procedure as in Example 1. However, during the kneading and extrusion process, the extrusion conditions were set so that the first outer layer had a thickness of 30 μm, the intermediate layer had a thickness of 740 μm, and the second outer layer had a thickness of 30 μm. The thickness of the resulting laminate sheet was 0.80 mm. The laminate sheet was molded in the same manner as in Example 1 to obtain a container. The shape of the container was the same as in Example 1.

Example 4
A third composition was prepared using the same procedure as in Example 1. A first resin composition and a second resin composition each consisting of 50% by mass of homopolypropylene (A) and 50% by mass of high-density polyethylene were prepared using a single-screw extruder. A laminate sheet and a container were then obtained using the same procedure as in Example 1. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Example 1.

Example 5
A laminate sheet was obtained using the same procedure as in Example 4. However, during the kneading and extrusion processing, the extrusion conditions were set so that the thickness of the first outer layer was 30 μm, the thickness of the intermediate layer was 740 μm, and the thickness of the second outer layer was 30 μm. The sheet thickness of the obtained laminate sheet was 0.80 mm. The laminate sheet was molded in the same manner as in Example 1 to obtain a container. The shape of the container was the same as in Example 1.

Example 6
A third composition was prepared using the same procedure as in Example 3. A first resin composition and a second resin composition each consisting of 80% by mass of homopolypropylene (B) and 20% by mass of a metallocene-based ethylene/α-olefin copolymer were prepared using a single-screw extruder. The first resin composition, the second resin composition, and the third composition were kneaded and extruded. Thereafter, a laminate sheet and a container were obtained using the same procedure as in Example 1. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Example 3.

Example 7
100 parts by mass of the compound of Example 1 was blended with 14.8 parts by mass of homopolypropylene (B) and 4.3 parts by mass of a metallocene-based ethylene/α-olefin copolymer, and kneaded using a twin-screw extruder. This resulted in a third composition containing 55.9% by mass of talc, 14.8% by mass of homopolypropylene (B), 25.0% by mass of block polypropylene, and 4.3% by mass of the metallocene-based ethylene/α-olefin copolymer. A laminate sheet and a container were then obtained using the same procedures as in Example 6. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Example 6.

(Comparative Example 1)
A compound masterbatch was prepared by kneading 61.3% by mass of talc, 19.3% by mass of homopolypropylene (A), and 19.4% by mass of high-density polyethylene using a twin-screw extruder. 7.0 parts by mass of high-density polyethylene was blended with 100 parts by mass of the compound and kneaded using a twin-screw extruder. This resulted in a third composition containing 57.0% by mass of talc, 17.2% by mass of homopolypropylene (A), and 25.8% by mass of high-density polyethylene. A first resin composition and a second resin composition, each consisting of 40% by mass of homopolypropylene (A) and 60% by mass of high-density polyethylene, were prepared using a single-screw extruder. The first resin composition, the second resin composition, and the third composition were kneaded and extruded. This resulted in a three-layer laminate sheet having, in that order, a first outer layer made of the first resin composition, an intermediate layer made of the third composition, and a second outer layer made of the second resin composition. During the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 35 μm, the thickness of the intermediate layer was 780 μm, and the thickness of the second outer layer was 35 μm. The resulting laminate sheet had a thickness of 0.85 mm. The laminate sheet was molded by solid-state pressure molding using a solid-state pressure molding machine to obtain a container in the shape of an inverted truncated cone with a bottom. The opening of the container had a diameter (caliber) of 88 mm, a depth of 55 mm, and an expansion ratio of 2.6.

(Comparative Example 2)
A third composition was prepared by kneading 34.5% by mass of talc, 26.2% by mass of homopolypropylene (A), and 39.3% by mass of high-density polyethylene using a twin-screw extruder. A first resin composition and a second resin composition, each consisting of 40% by mass of homopolypropylene (A) and 60% by mass of high-density polyethylene, were prepared using a single-screw extruder. The first resin composition, the second resin composition, and the third composition were kneaded and extruded. This resulted in a three-layer laminate sheet having, in this order, a first outer layer made of the first resin composition, an intermediate layer made of the third composition, and a second outer layer made of the second resin composition. During the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 30 μm, the thickness of the intermediate layer was 740 μm, and the thickness of the second outer layer was 30 μm. The sheet thickness of the resulting laminate sheet was 0.80 mm. The laminated sheet was molded by solid-state pressure molding using a solid-state pressure molding machine to obtain a container in the shape of an inverted truncated cone with a bottom. The container had an opening diameter (caliber) of 96 mm, a depth of 41 mm, and an expansion ratio of 2.1.

(Comparative Example 3)
100 parts by mass of the compound of Example 1 was blended with 20.2 parts by mass of high-density polyethylene and kneaded using a twin-screw extruder. This resulted in a third composition containing 55.9% by mass of talc, 23.9% by mass of block polypropylene, and 20.2% by mass of high-density polyethylene. A laminate sheet and a container were then obtained using the same procedures as in Example 1. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Example 1.

(1-2) Container evaluation

The following evaluations were performed on the containers of Examples 1 to 7 and Comparative Examples 1 to 3.

a. Side breakage and shape reproducibility during molding Containers that did not break the side during molding were evaluated as good (○), those with low shape reproducibility were evaluated as poor (△), and containers with side breakage were evaluated as poor (×). In this specification, a container with low shape reproducibility means a container that did not break the side but did not reproduce the shape of the mold, or a container that did not break the side and reproduced the shape of the mold but was partially thin and uneven in thickness, making it unsuitable for practical use. A laminated sheet used for a container with a good evaluation result (○) can be said to have good extensibility during molding.

b. Tear Resistance The tear resistance of the container was measured according to the following procedure in accordance with JIS K6252-1:2015. First, the side of the container was cut with scissors and punched out with the blade of a punching die for angle-shaped test specimens to prepare angle-shaped unnotched test specimens. Both ends of the test specimen were clamped with the chucks of a universal testing machine (manufactured by Toyo Seiki Seisakusho, Ltd., "Strograph VES5D") and pulled upward at a test speed of 50 mm/min. The maximum point strength, which is the force (unit: N/cm) required when the test specimen began to break, was measured. The higher the maximum point strength, the better the tear resistance and the more difficult it was to tear. Based on the measured maximum point strength, the tear resistance of the container was evaluated as follows.
(Maximum strength): (Evaluation)
1000 N / cm or more: particularly good tear resistance (A)
750 N/cm or more and less than 1000 N/cm: Good tear resistance (B)
Less than 750 N/cm: Poor tear resistance (C)

c. Cold Impact Resistance A preliminary test was conducted in advance using 10 containers (n = 10) to estimate the 50% fracture energy _E50 described below. The main test was then conducted using the procedure described below. A testing machine 20, as shown in Figures 1 and 2, was used in the preliminary and main tests. The testing machine 20 has a weight 21 equipped with a weight that can slide up and down, and a base 22 to which a pedestal 23 (see Figure 2) on which the container is placed is fixed. As shown in Figure 2, the container 10 to be tested is placed on the pedestal 23, which is fixed on the base 22. In the main test, the containers (n = 20 or more) were first stored at -20°C for 24 hours or more. Then, as shown in Figure 2, the container 10 was placed horizontally on the pedestal 23 of the testing machine 20, and a weight 21 weighing 1.0 kg was allowed to fall freely from above the horizontally positioned container 10 (i.e., from above the side). If even the slightest crack or break occurred at the opening of the container, the container was judged to have broken. The 50% breaking energy _E50 (unit: J) was calculated using the staircase method. A larger value of the 50% breaking energy _E50 indicates better cold impact resistance. Based on the value of the 50% breaking energy _E50 , the cold impact resistance of the container was evaluated as follows.
(50% breaking energy _E50 ): (Evaluation)
0.9 J or more: Particularly good cold impact resistance (A)
0.6 J or more and less than 0.9 J: Good cold impact resistance (B)
0.3 J or more and less than 0.6 J: poor cold impact resistance (C)
Less than 0.3 J: Particularly poor cold impact resistance (D)

d. Rigidity The container was placed with its bottom side facing up in a universal testing machine ("Strograph VES5D" manufactured by Toyo Seiki Seisakusho, Ltd.), and a load was applied from above at a test speed of 50 mm/min. The force (unit: kgf) required when the container began to collapse was measured. A larger measured value indicates better rigidity. Based on the measured values, the rigidity of the container was evaluated as follows.
(Measurement value): (Evaluation)
25 kgf or more: Particularly good rigidity (A)
15 kgfg or more and less than 25 kgf: Good rigidity (B)
5 kgfg or more and less than 15 kgf: Stiffness is somewhat good (C)
Less than 5 kgf: Poor rigidity (D)

These evaluation results are shown in Table 1 below. Note that in Table 1 below, "%" means "% by mass."

Comparing the results of Example 1 and Comparative Example 3 shown in Table 1 above, it can be seen that the inclusion of a metallocene-based ethylene/α-olefin copolymer in the intermediate layer improves tear resistance and cold impact resistance. Comparing the results of Examples 1 to 3, the higher the content of the metallocene-based ethylene/α-olefin copolymer, the better the impact resistance, and the lower the content of the metallocene-based ethylene/α-olefin copolymer, the better the rigidity. These results demonstrate that adjusting the content of the metallocene-based ethylene/α-olefin copolymer makes it possible to obtain a laminate sheet (laminate) with a good balance of tear resistance, cold impact resistance, and rigidity. Furthermore, comparing the results of Examples 6 and 7, it can be seen that the inclusion of homopolypropylene (B) (tensile modulus: 2000 MPa) in the intermediate layer slightly reduces tear resistance and cold impact resistance, but improves rigidity. These results demonstrate that the homopolypropylene with a high tensile modulus contained in the intermediate layer contributes to improving the rigidity of the laminate sheet (laminate).

(Example 8)
A laminate sheet was obtained using the same procedure as in Example 5. However, during the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 50 μm, the thickness of the intermediate layer was 1300 μm, and the thickness of the second outer layer was 50 μm. The sheet thickness of the obtained laminate sheet was 1.40 mm. The laminate sheet was molded using a solid-state pressure molding machine by solid-state pressure molding to obtain a container in the shape of an inverted truncated cone with a bottom. The diameter (caliber) of the opening of the container was 77 mm, the depth was 120 mm, and the expansion ratio was 5.4. The container was evaluated according to "a. Side surface fracture during molding and mold reproducibility." The container did not experience side surface fracture during molding and had sufficient mold reproducibility. These results demonstrate that the laminate sheet (laminate) of the present invention is suitable for manufacturing deep-draw containers.

(2) Test Example 2: Measuring Power Consumption

(2-1) Production of Laminated Sheet and Container According to the following production procedures, laminated sheets (laminates) and containers of Comparative Examples 4 and 5 were produced. Details of the raw materials used were as described in "a. Raw materials" in Test Example 1 above.

(Comparative Example 4)
A third composition was prepared by kneading 60.0% by mass of homopolypropylene (A) and 40.0% by mass of high-density polyethylene using a twin-screw extruder. A first resin composition and a second resin composition, each consisting of 50% by mass of homopolypropylene (A) and 50% by mass of high-density polyethylene, were prepared using a single-screw extruder. The first resin composition, the second resin composition, and the third composition were kneaded and extruded. This resulted in a three-layer laminate sheet having, in this order, a first outer layer made of the first resin composition, an intermediate layer made of the third composition, and a second outer layer made of the second resin composition. During the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 40 μm, the thickness of the intermediate layer was 1120 μm, and the thickness of the second outer layer was 40 μm. The sheet thickness of the resulting laminate sheet was 1.20 mm. The laminated sheet was molded by solid-state pressure molding using a solid-state pressure molding machine to obtain a container in the shape of an inverted truncated cone with a bottom. The container had an opening diameter (caliber) of 71 mm, a depth of 47 mm, and an expansion ratio of 2.3.

(Comparative Example 5)
A laminate sheet was obtained using the same procedure as in Comparative Example 2. However, during the kneading and extrusion process, the extrusion conditions were set so that the thickness of the first outer layer was 40 μm, the thickness of the intermediate layer was 1120 μm, and the thickness of the second outer layer was 40 μm. The sheet thickness of the obtained laminate sheet was 1.20 mm. Thereafter, a container was obtained using the same procedure as in Comparative Example 4. The thickness of each layer of the laminate sheet, the sheet thickness, and the shape of the container were the same as in Comparative Example 4.

(2-2) Container evaluation

The containers of Comparative Examples 4 and 5 were evaluated according to the procedures described in "a. Side surface fracture during molding and mold reproducibility" in Test Example 1 above.

(2-3) Measurement of power consumption The power consumption per unit volume of the laminated sheet during container molding in the solid-state pressure molding machine was measured for the containers of Comparative Examples 4 and 5 and the containers of Example 5 and Comparative Example 2 produced in Test Example 1, according to the procedure described below.

A wattmeter (manufactured by Hioki E.E. Corporation, trade name: Clamp-on Power Logger, model number: PW3365-10) was connected (clamped) to the wiring of the main breaker of the solid-state pressure molding machine to measure the power [kW], and this was multiplied by the time [h] required to mold 10,000 containers to convert it into an amount of power [kW·h]. Furthermore, the volume [cm ³ ] per shot of the laminate sheet fed to the solid-state pressure molding machine (sheet thickness [cm] × sheet width [cm] × sheet feed [cm]) was calculated. The amount of power was divided by the volume of the laminate sheet per shot to calculate the amount of power per unit volume of the laminate sheet [kW·h/cm ³ ].

The results of the above evaluations and measurements are shown in Table 2 below. Note that in Table 2 below, "%" means "% by mass."

When the talc content in the third composition was 0% by mass (Comparative Example 4), the power consumption was 0.565 kW·h/cm ^3. In contrast, when the talc content in the third composition was 55.9% by mass (Example 5), the power consumption was 0.488 kW·h/cm ^3. If the power consumption in Comparative Example 4 is taken as 100%, the power consumption in Example 5 was 86.4% of the power consumption in Comparative Example 4 (0.488 [kW·h/cm ³ ] / 0.565 [kW·h/cm ³ ] × 100 ≒ 86.4). This result supports the idea that when the talc content in the third composition exceeds 50% by mass, the power consumption can be reduced to 90% or less compared to when the talc content is 0% by mass.

Claims (10)

a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer;
the first outer layer is made of a first resin composition containing a first polyolefin-based resin,
the second outer layer is made of a second resin composition containing a second polyolefin-based resin,
the first polyolefin-based resin and/or the second polyolefin-based resin comprises homopolypropylene, a combination of homopolypropylene and high-density polyethylene, or a combination of homopolypropylene and metallocene-based ethylene/α-olefin copolymer;
the intermediate layer comprises talc, a metallocene- based ethylene/α-olefin copolymer, and a third polyolefin-based resin other than the metallocene -based ethylene/α-olefin copolymer (excluding high-density polyethylene) ;
the third polyolefin resin includes block polypropylene or a combination of block polypropylene and homopolypropylene,
The talc content is more than 50% by mass,
a third composition having a content of the metallocene-based ethylene/α-olefin copolymer of 1% by mass or more and 11% by mass or less ;
Laminate. The laminate according to claim 1 , wherein the first resin composition and/or the second resin composition further contains an inorganic filler. the first polyolefin resin and/or the second polyolefin resin contains the homopolypropylene,
The laminate according to claim 1 or 2 , wherein the homopolypropylene has a tensile modulus of 1500 MPa or more. the first polyolefin resin and/or the second polyolefin resin contains the homopolypropylene,
The laminate according to claim 1 or 2 , wherein the homopolypropylene has a tensile modulus of 1700 MPa or more. the first polyolefin-based resin and/or the second polyolefin-based resin comprises a combination of the homopolypropylene and the metallocene- based ethylene/α-olefin copolymer;
The laminate according to claim 1 or 2 , wherein the homopolypropylene has a tensile modulus of 1700 MPa or more. A container formed using the laminate according to any one of claims 1 to 5 . The container according to claim 6 , wherein the deployment ratio of the container is 2.0 or more. a first resin composition containing a first polyolefin-based resin;
a second resin composition containing a second polyolefin-based resin;
The present invention relates to a polyolefin resin composition comprising talc, a metallocene-based ethylene/α-olefin copolymer, and a third polyolefin resin other than the metallocene-based ethylene/α-olefin copolymer (excluding high-density polyethylene) ,
The talc content is more than 50% by mass,
a third composition having a content of the metallocene-based ethylene/α-olefin copolymer of 1% by mass or more and 11% by mass or less ;
Using
a first outer layer made of the first resin composition;
a second outer layer made of the second resin composition; and
an intermediate layer formed between the first outer layer and the second outer layer and comprising the third composition;
the first polyolefin-based resin and/or the second polyolefin-based resin comprises homopolypropylene, a combination of homopolypropylene and high-density polyethylene, or a combination of homopolypropylene and metallocene-based ethylene/α-olefin copolymer;
The third polyolefin resin includes block polypropylene or a combination of block polypropylene and homopolypropylene .
A method for manufacturing a laminate. a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer;
the first outer layer is made of a first resin composition containing a first polyolefin-based resin,
the second outer layer is made of a second resin composition containing a second polyolefin-based resin,
the first polyolefin-based resin and/or the second polyolefin-based resin comprises homopolypropylene, a combination of homopolypropylene and high-density polyethylene, or a combination of homopolypropylene and metallocene-based ethylene/α-olefin copolymer;
the intermediate layer comprises talc, a metallocene- based ethylene/α-olefin copolymer, and a third polyolefin-based resin other than the metallocene -based ethylene/α-olefin copolymer (excluding high-density polyethylene) ;
the third polyolefin resin includes block polypropylene or a combination of block polypropylene and homopolypropylene,
The talc content is more than 50% by mass,
a third composition having a content of the metallocene-based ethylene/α-olefin copolymer of 1% by mass or more and 11% by mass or less ;
The laminate
Molding the mixture by a solid-state molding machine.
Container manufacturing method. In the solid-phase molding machine, the amount of power consumed per unit volume of the laminate during molding of the container is:
The method for manufacturing a container according to claim 9 , wherein the power consumption is 90% or less of the amount of power consumed when the content of the talc in the third composition is 0% by mass.