JP5198333B2 - Polyethylene resin material for foamable laminate, foamable laminate, foamed paper using the same, and heat insulating container - Google Patents

Description

  The present invention relates to a polyethylene resin material for a foamable laminate, a foamable laminate, a foamed paper using the same, and a heat-insulating container, and more specifically, water vapor released from a paper-based substrate by heating, A polyethylene resin material, a foamable laminate, a foamed paper using the same, a cup, and the like as a raw material of a foamable laminate that can obtain a foam cell (foamed layer) having a sufficiently high height by a gas such as a volatile gas It relates to an insulated container.

  Conventionally, as a container having heat insulation properties, a synthetic resin foam is often used. In addition, as a container that is easy to dispose and has good printability, a heat-insulated paper container that uses multiple sheets of paper, or a material in which both sides of a paper substrate are laminated with a polyethylene resin layer, foam the surface of the polyethylene resin layer to insulate it. There is a paper container that has been imparted.

As a paper-based technology, polyethylene is extruded and laminated on at least one side of the paper, a vapor pressure holding layer is formed on the other side, and heated to produce a processed paper having irregular irregular patterns on the surface. (For example, refer to Patent Document 1). In addition, a technique has been proposed in which a thermoplastic resin film is laminated or coated on one side wall surface of a body member, and a foamed heat insulation layer is formed by foaming the film by heating (see, for example, Patent Document 2). Further, in a paper container composed of a container body member and a bottom member, a part of the outer wall surface of the container body member is printed with an organic solvent-containing ink, and the entire outer surface of the body member is covered with a thermoplastic synthetic resin film. A technique has been proposed in which a relatively thick foam layer is present in a printed portion by heating a paper container (see, for example, Patent Document 3). Furthermore, the foaming which consists of the laminated body provided with the ethylene-alpha olefin copolymer polymerized using the single site catalyst at least from the outer surface side or the foaming layer containing the same, the base material layer mainly made of paper, and the thermoplastic resin layer Processed paper has been proposed (see, for example, Patent Documents 4 and 5).
Moreover, in patent document 6, the time until a thermoplastic resin in a molten state comes into contact with the paper base material from the T-die on at least one surface of the paper base material of the body member raw material sheet in the paper container is 0.11 to 0.33. A raw material sheet for a body member of a paper container formed by extrusion lamination so as to be seconds is shown, and a composition in which two kinds of low density polyethylene are mixed to adjust MFR is described. The processed paper having the foamed layer thus obtained, when used as a container, is well-familiar with the hand due to the foamed layer and is not slippery and has excellent heat insulation properties, as compared to a heat-insulated container using multiple sheets of paper. There is an advantage that the cost is low.

However, the conventional laminate having a foam layer and processed paper using the same have not been sufficiently foamable, and further improvement in foamability has been desired. Further, when the MFR is increased in order to improve the foamability, there is a problem that the appearance of the foam layer becomes poor and the workability at the time of extrusion laminating becomes unstable.
Furthermore, since it is necessary to set the temperature at the time of foaming higher in these foaming processes, not only the energy efficiency tends to be bad, but it is necessary to set the temperature at the time of heat sealing and making the body member high. For this reason, a material with good heat sealability is desired.

Japanese Patent Publication No. 48-32283 JP-A-57-110439 Japanese Patent Laid-Open No. 7-232774 Japanese Patent Laid-Open No. 10-128928 JP 2007-168178 A JP 2008-105747 A

  In view of the above problems, an object of the present invention is to provide foaming cells (foaming layers) having a sufficiently high height by a gas such as water vapor or volatile gas released from a paper-based substrate by heating. It is providing the heat insulation container, such as a polyethylene resin material used as the raw material for manufacture of a laminated body, a foamable laminated body, a foamed paper using the same, and a cup.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has heated the paper substrate (I) on one surface of the substrate (I) mainly composed of paper and the substrate mainly composed of the paper. As a raw material for producing a laminate having a polyethylene-based resin layer (I) that is foamed by water vapor or the like released from water, a specific amount of a specific ethylene-α-olefin copolymer and radical polymerization polyethylene resin is blended, By using a polyethylene resin material in which the CFC elution component amount and elution temperature of this blend are adjusted to specific values, a laminate excellent in heat sealability and foamability at a low temperature can be obtained. The present inventors have found that a foamed paper and a heat-insulated container having a good appearance of the foamed layer can be produced.

That is, according to the first aspect of the present invention, at least the gas released from the base material by heating on one side of the base material (I) mainly composed of paper and the base material mainly composed of the paper. A polyethylene-based resin material (X) for a foamable laminate having a polyethylene-based resin layer (II) foamed by an ethylene-α-olefin copolymer having the following characteristics (a1) and (a2) ( A) It is obtained by blending more than 50% by weight and 90% by weight or less and 10% by weight or more and less than 50% by weight of the high-pressure radical polymerization polyethylene resin (B), and has the following characteristics (X1) to (X5) A polyethylene-based resin material for a foamable laminate is provided.
(A1) MFR measured according to JIS K7210 is 1 to 50 g / 10 min,
(A2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 to 0.935 g / cm ³ .
(X1) Melt flow rate (MFR) measured in accordance with JIS K7210 is 1 to 30 g / 10 min,
(X2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 g / cm ³ or more,
(X3) The amount of elution components at an elution temperature of 80 ° C. or higher by a cross fractionation chromatograph (CFC) is 10% by weight or less,
(X4) The maximum peak temperature of elution temperature by cross fractionation chromatograph (CFC) is 70 ° C. or less,
(X5) MFR and memory effect (ME) satisfy the following formula (1).
−0.467 × Ln (MFR) + 2.75 ≦ ME (1)
(In the formula, Ln is a natural logarithm.)

  According to a second invention of the present invention, in the first invention, the ethylene-α-olefin copolymer (A) is a resin produced using a single site catalyst. A polyethylene-based resin material for a laminate is provided.

According to a third invention of the present invention, in the first or second invention, the high pressure radical polymerization polyethylene resin (B) is a low density polyethylene resin satisfying the following properties (b1) to (b2). There is provided a polyethylene resin material for a foamable laminate, which is characterized in that
(B1) The melt flow rate (MFR) measured according to JIS K7210 is 1 to 30 g / 10 min.
(B2) The density measured according to the test temperature of 23 ° C. and JIS K7112 is 0.910 to 0.940 g / cm ³ .

According to a fourth invention of the present invention, in any one of the first to third inventions, the high-pressure radical polymerization polyethylene resin (B) satisfies the following properties (b1) to (b2): It is characterized by comprising a high-pressure radical polymerization method low-density polyethylene resin in which at least two kinds of polyethylene resin (B11) and low-density polyethylene resin (B12) satisfying the following properties (b3) to (b5) are mixed. A polyethylene-based resin material for foamable lamination is provided.
(B1) MFR measured according to JIS K7210 is 1 to 30 g / 10 min.
(B2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.910 to 0.935 / cm ³ .
(B3) MFR measured according to JIS K7210 is 0.1 to 100 g / 10 min.
(B4) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.910 to 0.940 g / cm ³ .
(B5) A memory effect (ME) measured using a melt indexer used in JIS K7210 under the conditions of a cylinder temperature of 240 ° C. and a constant speed extrusion rate of 3 g / min is 1.5 or more.

  According to a fifth invention of the present invention, according to any one of the first to fourth inventions, the polyethylene-based resin material (X) is formed on one surface of the base material (I) mainly composed of paper. A foamable laminate obtained by forming a polyethylene resin layer (II) is provided.

  According to the sixth aspect of the present invention, in the fifth aspect, the heat for holding the gas released from the base material (I) on the other surface of the base material (I) mainly composed of paper. A foamable laminate is provided in which a thermoplastic resin layer (III) made of a plastic resin (D) is formed.

  According to the seventh aspect of the present invention, there is provided foamed paper obtained by heating the foamable laminate and foaming the polyethylene resin layer (II) in the fifth or sixth aspect.

  According to an eighth invention of the present invention, in the seventh invention, there is provided a foam-processed paper characterized in that the height of the foamed cell formed by foaming the polyethylene resin layer (II) is 300 μm or more. Provided.

  According to a ninth invention of the present invention, according to the fifth or sixth invention, after the container is formed using the foamable laminate, the container is heated to foam the polyethylene resin layer (II). Insulated containers are obtained.

  According to a tenth aspect of the present invention, in the ninth aspect, there is provided a heat insulating container characterized in that the heat insulating container is a cup-shaped container.

  According to an eleventh aspect of the present invention, in accordance with any one of the first to fourth aspects of the invention, one side of the base material (I) mainly composed of paper using the foamable laminated polyethylene resin material. A thermoplastic resin (D) having a polyethylene resin layer (II) formed thereon and holding the gas released from the base material (I) on the other side of the base material (I) mainly comprising paper, if necessary After forming the thermoplastic resin layer (III) consisting of the above, to obtain a foamable laminate, this is molded into a container, and subsequently heated to a temperature of 100 to 200 ° C. to form a base material mainly composed of paper ( There is provided a method for producing a heat-insulating container, wherein the polyethylene-based resin layer (II) is foamed by a gas released from I).

  The polyethylene-based resin material for foamable laminates of the present invention contains a specific amount of a specific ethylene-α-olefin copolymer and a radical polymerization polyethylene resin, and has a specific CFC elution component amount and elution temperature. Therefore, low temperature heat sealability is good, and it is not necessary to set the temperature at the time of foaming high in the foaming process of the laminate obtained by using this, energy efficiency is improved and the body member is heat sealed Therefore, it is not necessary to set a high temperature when creating. In addition, by using this material, it is possible to easily produce foamed paper and a heat-insulated container having a good appearance of the foamed layer.

Method for obtaining molecular weight distribution when peak of BHT added to solvent at first elution temperature of CFC overlaps low molecular weight side of elution component when preparing polyethylene-based resin material for foamable laminate in the present invention Is shown.

  Hereinafter, the polyethylene resin material for a foamable laminate of the present invention, the foamable laminate, foamed paper using the same, and a heat insulating container will be described in detail for each item.

1 [Polyethylene resin material (X) for foamable laminate]
The polyethylene resin material for a foamable laminate of the present invention is a gas released from a base material by heating on at least one surface of the base material (I) mainly composed of paper and the base material mainly composed of paper. An ethylene-α-olefin copolymer having the following characteristics (a1) and (a2), which is a polyethylene resin material (X) for a foamable laminate having a polyethylene resin layer (II) foamed by: (A) It is obtained by blending more than 50 and 90% by weight or less and high-pressure radical polymerization polyethylene resin (B) in a range of 10 to less than 50% by weight, and has the following characteristics (X1) to (X5) And
(A1) MFR measured according to JIS K7210 is 1 to 50 g / 10 min,
(A2) The test temperature is 23 ° C. and the density measured according to JIS K7112 is 0.880 to 0.935 g / cm ³ .
(X1) Melt flow rate (MFR) measured in accordance with JIS K7210 is 1 to 30 g / 10 min,
(X2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 g / cm ³ or more,
(X3) The amount of elution components at an elution temperature of 80 ° C. or higher by a cross fractionation chromatograph (CFC) is 10% by weight or less,
(X4) The maximum peak temperature of elution temperature by cross fractionation chromatograph (CFC) is 70 ° C. or less,
(X5) MFR and memory effect (ME) satisfy the following formula (1).
−0.467 × Ln (MFR) + 2.75 ≦ ME (1)
(In the formula, Ln is a natural logarithm.)

(1) [Ethylene / α-olefin copolymer (A)
In the present invention, the ethylene / α-olefin copolymer (A) has (a1) a melt flow rate (MFR) measured in accordance with JIS K7210 of 1 to 50 g / 10 minutes, and (a2) a test temperature of 23 ° C. , An ethylene / α-olefin copolymer having a density measured in accordance with JIS K7112 of 0.880 to 0.935 g / cm ³ .

  The melt flow rate (MFR) of the ethylene / α-olefin copolymer (A) is measured in accordance with (a1) JIS K7210, and is 1 to 50 g / 10 minutes, preferably 1.5 to 45 g / 10 minutes. More preferably, it is selected in the range of 2 to 40 g / 10 minutes. An MFR of less than 1 g / 10 minutes is not preferable because the extrusion load during extrusion lamination is high and high-speed workability deteriorates. Moreover, when the MFR exceeds 50 g / 10 min, the processability of the extrusion laminate becomes unstable, which is not preferable.

The density of the ethylene / α-olefin copolymer (A) is (a2) 0.880 to 0.935 g / cm ³ , preferably 0.890 to 0.933 g / cm ³ , more preferably 0.895. ˜0.930 g / cm ³ . The said seal degree 0.880 g / cm less than ^3, the roll peeling property is deteriorated at the time of lamination, if it exceeds 0.935 g / cm ^3, the polyethylene-based resin material CFC elution temperature 80 ° C. or more of the (X) There is a possibility that the elution component amount may not satisfy the condition of 10 wt% or less.

The α-olefin is preferably a linear or branched olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1- Examples include octene and 1-decene. Among these copolymers, binary such as ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene / 1-octene copolymer, etc. A terpolymer such as a copolymer, an ethylene / propylene / 1-hexene copolymer, and an ethylene / 1-butene / 1-hexene copolymer is preferred.
The total content of these α-olefins is usually 30 mol% or less, preferably 3 to 20 mol%.

  The ethylene / α-olefin copolymer (A) is a low, medium and high pressure, slurry polymerization method, solution using an ion polymerization catalyst such as a Ziegler catalyst, a Phillips catalyst, a single-site catalyst, etc. It can be produced by a polymerization method, a gas phase polymerization method, etc., and can be suitably produced by controlling polymerization conditions such as polymerization temperature and pressure, a co-catalyst and the like.

Among the ethylene / α-olefin copolymers (A), a resin produced with a single-site catalyst is preferable, and in particular, an ultra-low density polyethylene resin or a linear low density polyethylene having a density of 0.880 to 0.935 g / cm ^3. Resin is included.
Ultra-low density polyethylene resins and linear low density polyethylene resins produced with these single-site catalysts have fewer low molecular weight components than those produced with conventional Ziegler catalysts and Philips catalysts, and have transparency and blocking resistance. In addition, it has a low melting point and good high-speed sealing properties, and is suitably used for extrusion laminate molding, sealant film and the like.
In the present invention, a linear low-density polyethylene resin having a long-chain branch and an ultra-low-density polyethylene resin produced with a single-site catalyst, which has been remarkably developed recently, are also preferable. Specific examples of linear low density polyethylene and ultra-low density polyethylene produced with these single-site catalysts include Kernel (registered trademark), Harmolex (registered trademark, manufactured by Nippon Polyethylene Co., Ltd.), Evolue (registered trademark, Mitsui Chemicals, Inc.), Exact (registered trademark, manufactured by ExxonMobil), Affinity (registered trademark, manufactured by Dow Chemical Company), and the like.

  The ethylene / α-olefin copolymer produced by the above single-site catalyst is generally a group IV transition metal compound containing a ligand having a cyclopentadienyl skeleton, and if necessary. It is obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a catalyst containing a cocatalyst, an organoaluminum compound and a carrier. For example, JP-A-60-35006 And a metallocene catalyst disclosed in JP-A-60-35007, JP-A-60-35008, JP-A-03-163088, JP-A-61-296008, etc. Can do.

The ethylene / α-olefin copolymer in the present invention is produced by a gas phase polymerization method, a slurry polymerization method, a solution polymerization method or the like substantially free of a solvent in the presence of the catalyst, and substantially contains oxygen, water, etc. Inactive carbon exemplified by aliphatic hydrocarbons such as butane, pentane, hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. It is produced in the presence or absence of a hydrogen fluoride solvent. The polymerization conditions are not particularly limited, but the polymerization temperature is usually 15 to 350 ° C., preferably 20 to 200 ° C., more preferably 50 to 110 ° C., and the polymerization pressure is usually from normal pressure to low pressure. 70 kg / ^cm 2 G, preferably normal pressure to 20 kg / cm ² G, the case of high pressure process, usually less desirable 1500kg / cm ² G. In the case of the low and medium pressure method, the polymerization time is usually 3 minutes to 10 hours, preferably about 5 minutes to 5 hours. In the case of the high pressure method, it is usually 1 minute to 30 minutes, preferably about 2 minutes to 20 minutes. In addition, the polymerization is not particularly limited to a one-stage polymerization method, but also a two-stage or more multi-stage polymerization method in which polymerization conditions such as a hydrogen concentration, a monomer concentration, a polymerization pressure, a polymerization temperature, and a catalyst are different from each other.
In addition, the ethylene / α-olefin copolymer is not particularly limited to the production catalyst, process, etc., but the book “Polyethylene Technology Reader” (edited by Kazuo Matsuura and Naotaka Mikami, published by the Industrial Research Council, 2001) P. 123-160, p. It is possible to manufacture by the method described in 163-196 etc.

2 High pressure radical polymerization polyethylene resin (B)
In the present invention, the high-pressure radical polymerization polyethylene resin (B) is a polyethylene resin produced by a high-pressure radical polymerization method. The high-pressure radical polymerization low-density polyethylene resin (B1) (hereinafter referred to as low-density polyethylene), or 2 Including low-density polyethylene resin composition of more than species, copolymer of ethylene and vinyl ester (B2), copolymer of ethylene and α, β-unsaturated carboxylic acid or derivative thereof (B3), and mixtures thereof To do.

(B1) Low-density polyethylene resin In the present invention, the low-density polyethylene resin (LDPE) has a melt flow rate (MFR) measured in accordance with JIS K7210 (190 ° C., 21.18 N load) of 1 to 30 g / 10. Minutes, preferably 1.5 to 28 g / 10 minutes, more preferably 2 to 25 g / 10 minutes. When the melt flow rate (MFR) is less than 1 g / 10 minutes, the extrusion load is high and high-speed processability is deteriorated. On the other hand, those having a melt flow rate (MFR) exceeding 30 g / 10 min are not preferred because the processing stability during extrusion lamination molding deteriorates.

Further, the test temperature is 23 ° C., and the density according to JIS K7112 is 0.910 to 0.935 g / cm ³ , preferably 0.912 to 0.933 g / cm ³ , 0.915 to 0.930 g / cm ³ . A range of ³ is selected. When the density is less than 0.910 g / cm ³ , slip during lamination molding is deteriorated and handling of the laminate is deteriorated. Moreover, when the density exceeds 0.935 g / cm ³ , the low-temperature heat seal deteriorates, which is not preferable.

(B2) Copolymer of ethylene and vinyl ester The ethylene and vinyl ester copolymer (B2) is mainly composed of ethylene, vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, stearin. It is a copolymer with vinyl ester monomers such as vinyl acid and vinyl trifluoroacetate. Among these, vinyl acetate is particularly preferable.
A copolymer comprising 50 to 99.5% by weight of ethylene, 0.5 to 50% by weight of vinyl ester, and 0 to 49.5% by weight of other copolymerizable unsaturated monomers is preferred. Further, the vinyl ester content is selected in the range of 3 to 20% by weight, particularly preferably 5 to 15% by weight.

(B3) Copolymer of ethylene and α, β-unsaturated carboxylic acid or derivative thereof As a typical copolymer of a copolymer of ethylene and α, β-unsaturated carboxylic acid or derivative thereof, , Ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene-maleic anhydride copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate copolymer Polymers, ethylene / (meth) acrylic acid alkyl ester copolymers such as ethylene / ethyl methacrylate copolymer; ethylene / maleic anhydride / vinyl acetate copolymer, ethylene / maleic anhydride / methyl acrylate copolymer Binary copolymer such as ethylene, maleic anhydride / ethyl acrylate copolymer, ethylene / glycidyl acrylate / vinyl acetate, etc. Examples thereof include a polymer or a multi-component copolymer.

That is, these comonomers include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, acrylic acid-n -Butyl, methacrylic acid-n-butyl, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, glycidyl acrylate and the like.
Among these, alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate are particularly preferable. In particular, the (meth) acrylic acid ester content is in the range of 3 to 30% by weight, preferably 5 to 20% by weight.

(3) High-pressure radical polymerization method (i) Polymerization conditions The high-pressure radical polymerization method according to the present invention is produced by bulk or solution polymerization under ultrahigh pressure in the presence of a radical initiator such as oxygen or organic peroxide. .
The polymerization temperature is 100 to 300 ° C, preferably 120 to 280 ° C, more preferably 150 to 250 ° C. If the polymerization temperature is less than 100 ° C., the yield may be lowered or a stable product may not be produced. On the other hand, if the polymerization temperature exceeds 300 ° C., the reaction may not be stable and a polymer having a large molecular weight may be obtained. It becomes difficult.
The polymerization pressure is 50 to 400 MPa, preferably 70 to 350 MPa, more preferably 100 to 300 MPa. If the polymerization pressure is less than 50 MPa, a product having a sufficient molecular weight cannot be obtained, and the processability and physical properties are low. On the other hand, when the pressure exceeds 400 MPa, it is difficult to perform a stable production operation.

(Ii) Polymerization Operation In production, basically, the production equipment and technology of ordinary high-pressure radical polymerization method low-density polyethylene can be used. As the reactor type, an autoclave type with a stirring blade or a tubular type can be used. If necessary, a plurality of reactors are connected in series or in parallel to perform multistage polymerization. You can also. Further, in the case of an autoclave type reactor, it is possible to provide temperature distribution by dividing the inside of the reactor into a plurality of zones, and to perform more precise temperature control. By such an operation, it is possible to control a memory effect or the like.

(Iii) Radical initiator As the radical initiator, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2 , 5-Dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (t-butylperoxy) hexane, lauroyl peroxide, t-butylperoxy Benzoate, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, t-butylcumyl peroxide, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, di -T-Butyldiperoxyisophthalate, n-butyl-4,4-bis (t-butylperoxy ) Valerate, t-butyl peroxybenzoate, t-butyl peroxyacetate, cyclohexanone peroxide, t-butyl peroxylaurate, acetyl peroxide, i-butyl peroxide, octanoyl peroxide, t-butyl peroxide Valate, t-butyl hydroperoxide, cumene hydroperoxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 1,1-bis t-butylperoxycyclohexane, 2,2-bis Organic peroxides such as t-butylperoxyoctane and 2,2-azobisisobutyronitrile are exemplified. Among these, a decomposition temperature for obtaining a half-life of 1 minute is preferably 160 to 200 ° C.

  The blending amount of the radical initiator is not particularly limited, but is 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, more preferably 0.5 to 2 parts by weight with respect to 100 parts by weight of polyethylene. It is a range. If necessary, the molecular weight may be adjusted using a chain transfer agent or the like.

(Iv) Chain transfer agent Examples of the chain transfer agent include hydrogen, propylene, butene-1, C _{1 to} C ₂₀ or more saturated aliphatic hydrocarbons or halogen-substituted hydrocarbons such as methane, ethane, propane, and butane. , isobutane, n- hexane, n- heptane, cycloparaffins, chloroform, carbon _{tetrachloride,} C 1 _{-C 20} or more saturated aliphatic alcohols, such as methanol, ethanol, propanol and _isopropanol, C 1 _{-C 20} or Further saturated aliphatic carbonyl compounds such as acetone and methyl ethyl ketone, and aromatic compounds such as toluene, diethylbenzene and xylene are mentioned.

In the present invention, the high-pressure radical polyethylene resin (B) is more preferably a low-density polyethylene resin (LDPE), its composition, or a composition mainly composed of it, because it has good moldability during laminate molding.
Specifically, low density polyethylene resin (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene- Ethylene- (meth) acrylic acid ester copolymers such as glycidyl acrylate (EGMA), ethylene-glycidyl acrylate-vinyl acetate copolymer (E-GMA-VA), ethylene-maleic anhydride-methyl acrylate copolymer Ternary copolymer such as coalescence, two kinds of low density polyethylene resin compositions, composition of low density polyethylene resin and ethylene-vinyl acetate copolymer (EVA), low density polyethylene resin and ethylene-methyl acrylate copolymer Examples thereof include a composition with a polymer (EMA).

(4) Low Density Polyethylene Resin Composition In the present invention, the low density polyethylene resin composition is a low density polyethylene resin composition in which two or more of the high pressure radical polymerization polyethylene resins (B11) and (B12) are mixed. Preferably, a composition of a specific high MFR low density polyethylene resin (B11) and a specific low MFR and low density polyethylene resin (B12) having a high memory effect (ME), comprising the following (b1) to ( Low density polyethylene resin (B11) 95-5% by weight satisfying the requirements of b2) and low density polyethylene resin (B12) 95% satisfying the following requirements (b3) to (b5) other than the (B11) resin A low density polyethylene resin composition comprising 5% by weight.
(B1) MFR (b) measured in accordance with JIS K7210 (190 ° C., 21.18 N load) is 1 to 30 g / 10 minutes,
(B2) The test temperature is 23 ° C., and the density according to JIS-K7112 is 0.910 to 0.940 g / cm ³ .
(B3) MFR (b) measured in accordance with JIS K7210 (190 ° C., 21.18 N load) is 0.1 to 100 g / 10 min.
(B4) Test temperature 23 ° C., density according to JIS K7112 is 0.910 to 0.940 g / cm ³ ,
(B5) A memory effect (ME) measured by using a melt indexer defined by JIS K7210 under the conditions of a cylinder temperature of 240 ° C. and a constant speed extrusion rate of 3 g / min is 1.5 or more.

(B11) Low density polyethylene resin The low density polyethylene resin (B11) has an MFR of 1 to 30 g / 10 min measured according to (b1) JIS K7210 (190 ° C., 21.18 N load), (b2) Test temperature It is a low density polyethylene resin satisfying a density of 0.905 to 0.940 g / cm ³ or less at 23 ° C. and JIS K7112.

  The MFR of the low-density polyethylene resin (B11) is (b1) MFR (b2) measured in accordance with JIS K7210 (190 ° C., 21.18 N load) is 1 to 30 g / 10 minutes, preferably 1.2 to 27 g. / 10 minutes, more preferably in the range of 1.5 to 25 g / 10 minutes. When the MFR is less than 1 g / 10 minutes, the extrusion load during extrusion lamination is high, and high-speed workability is deteriorated. Moreover, when MFR exceeds 30 g / 10 minutes, since extrusion laminate processability may become unstable, it is not preferable.

The density of the low density polyethylene resin (B11) is (b2) measured at a test temperature of 23 ° C. in accordance with JIS K7112, and is 0.910 to 0.940 g / cm ³ , preferably 0.912 to 0.937 g. / Cm ³ , more preferably in the range of 0.915 to 0.935 g / cm ³ . If the density is less than 0.910 g / cm ³ , slip during lamination molding is worsened, and there is a concern that handling of the laminate is worsened. Moreover, what a density exceeds 0.940 g / cm < ³ > becomes a thing which is difficult to manufacture industrially.

(B12) Low density polyethylene resin The low density polyethylene resin (B12) has an MFR (c) of 0.1 to 100 g / 10 min measured according to (b3) JIS K7210 (190 ° C., 21.18 N load), (B4) The test temperature is 23 ° C., the density according to JIS K7112 is 0.910 to 0.940 g / cm ³ , (b5) The melt indexer used in JIS K7210 is used, and the measurement conditions are a cylinder temperature of 240 ° C. A low-density polyethylene resin having a memory effect (ME) of 1.5 or more measured under conditions of a constant speed extrusion rate of 3 g / min.

  Regarding the MFR of the low density polyethylene resin (B12), the MFR (c) measured in accordance with (b3) JIS K7210 (190 ° C., 21.18 N load) is 0.1 to 100 g / 10 min, preferably 0.8. It is 5 to 80 g / 10 minutes, more preferably 1 to 70 g / 10 minutes. An MFR (c) of less than 0.1 g / 10 minutes is not preferable because the extrusion load during extrusion lamination is high and the high-speed workability deteriorates. Moreover, when MFR exceeds 100 g / 10min, since the processing stability at the time of an extrusion lamination process may worsen, it is unpreferable.

Moreover, about the density of the said low density polyethylene resin (B12), the density based on (b4) test temperature 23 degreeC and JISK7112 is 0.910-0.940g / cm < ³ >, Preferably it is density 0.912-0. It is 937 g / cm < ³ >, More preferably, it is the range of 0.915-0.935 g / cm < ³ >. If the density is less than 0.910 g / cm ³ , slip during lamination molding is worsened, and there is a concern that handling of the laminate is worsened. Moreover, what a density exceeds 0.940 g / cm < ³ > becomes a thing which is difficult to manufacture industrially.

  Further, the memory effect of the low density polyethylene resin (B12) was measured using (b5) a melt indexer defined by JIS K7210, under the measurement conditions of a cylinder temperature of 240 ° C. and a constant speed extrusion rate of 3 g / min. The memory effect (ME) is 1.5 or more, preferably 1.7 or more, more preferably 1.9 or more. If the memory effect is less than 1.5, the preparation range for adjusting the polyethylene resin material (X) described later is limited, which causes excessive neck-in at the time of processing such as extrusion laminating, and causes unstable processability. In addition, there is a concern that the expansion ratio may be improved and a uniform foam cell may not be obtained.

Moreover, also in the said low density polyethylene resin (B1) and a low density polyethylene composition, MFR (c) and a memory effect (ME) satisfy | fill following formula (2), Preferably Formula (2-1) More preferably, it is desirable to satisfy the formula (2-2).
−0.467 × Ln (MFR (c)) + 2.75 ≦ ME −−−- type (2)
(Where Ln is the natural logarithm)
−0.467 × Ln (MFR (c)) + 2.77 ≦ ME −−−- type (2-1)
−0.467 × Ln (MFR (c)) + 2.79 ≦ ME −−−- formula (2-2)
When the memory effect (ME) is less than −0.467 × Ln (MFR) +2.75, the height of the foam cell does not increase, the neck-in during processing such as extrusion lamination increases, and the workability also increases. There is a risk of instability.

Further, the relationship between the MFR (b) of the low density polyethylene resin (B11) and the MFR (c) of the low density polyethylene resin (B12) of the low density polyethylene resin composition of the present invention is the following formula (3), preferably It is desirable to satisfy Formula (3-1).
MFR (b) / MFR (c)> 1 ----- (3)
MFR (b) / MFR (c)> 2 ----- (3-1)

  By satisfying the above expression (3), the moldability at the time of laminate molding becomes smoother and the loss due to neck-in is greatly improved. Moreover, the foamability at the time of manufacturing a foamed paper and a heat insulation container becomes favorable.

The blending ratio of the high pressure radical polymerization method low density polyethylene resin (B11) and the high pressure radical polymerization method low density polyethylene resin (B12) is 5 to 95% by weight of the resin (B11), and the high pressure radical polymerization method low density polyethylene resin (B12). ) 95-5 wt%, preferably 10-90 wt% resin (B11) and 90-10 wt% resin (B12), more preferably 15-85 wt% resin (B11) and 85-15 wt% resin (B12). % Range.
However, it is important that the low-density polyethylene composition satisfies the physical properties (b1) and (b2) of the high-pressure radical polymerization polyethylene resin (B) depending on the blending amount.

The polyethylene-based resin material (X) for the foamable laminate of the present invention has (a1) a melt flow rate (MFR) measured in accordance with JIS K7210 of 1 to 50 g / 10 min, (a2) a test temperature of 23 ° C., The density measured in accordance with JIS K7112 consists of an ethylene-α-olefin copolymer (A) having 0.880 to 0.935 g / cm ³ and a high-pressure radical polymerization polyethylene resin (B). The blending ratio of () exceeds 50 wt% and 90 wt% or less, the blending ratio of (B) is 10 wt% or more and less than 50 wt%, and has the following characteristics (x1) to (x5).
(X1) Melt flow rate (MFR) measured in accordance with JIS K7210 is 1 to 30 g / 10 min,
(X2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 g / cm ³ or more,
(X3) The amount of elution components with an elution temperature of 80 ° C. or higher in a cross fractionation chromatograph (CFC) is 10% by weight or less,
(X4) The maximum peak temperature of the elution temperature of the cross fractionation chromatograph (CFC) is 70 ° C. or less,
(X5) MFR and memory effect (ME) satisfy the following formula (1).
−0.467 × Ln (MFR) + 2.75 ≦ ME (Formula 1)
(In the formula, Ln is a natural logarithm.)

(X1) Melt flow rate (MFR)
The MFR of the polyethylene resin material (X) for the foamable laminate of the present invention is measured in accordance with (x1) JIS K7210, and is 1 to 30 g / 10 min, preferably 1.2 to 27 g / 10 min. Preferably it is 1.5-25g / 10min. When the MFR is less than 1 g / 10 minutes, the extrusion load is high and the high-speed workability deteriorates. On the other hand, when the MFR exceeds 30 g / 10 min, the processing stability at the time of extrusion lamination molding deteriorates, which is not preferable.
The MFR of the present invention is a value measured according to JIS-K7210 (190 ° C., 21.18 N load) unless otherwise specified.

(X2) Density The density of the polyethylene-based resin material for foamable laminates of the present invention is (x2) measured at a test temperature of 23 ° C. in accordance with JIS K7112, and is 0.880 g / cm ³ or more, preferably 0.8. It is selected in the range of 890 to 0.935 g / cm ³ , more preferably 0.900 to 0.930 g / cm ³ . When the density is less than 0.880 g / cm ³ , slip during lamination molding is deteriorated and handling of the laminate is deteriorated. Moreover, when the density exceeds 0.935 g / cm ³ , there is a possibility that the processing stability at the time of extrusion lamination molding deteriorates.

(X3) Cross-fractionation chromatograph (CFC) elution amount The cross-fractionation chromatograph (CFC) of the polyethylene-based resin material for foamable laminates of the present invention is measured by the test method described later, and temperature rising elution is performed for crystalline fractionation. It consists of a fractionation (TREF) part and a gel permeation chromatography (GPC) part for molecular weight fractionation.

  The amount of elution components with an elution temperature of 80 ° C. or higher as measured by (x3) CFC is 10% by weight or less. If the amount of the elution component with a CFC elution temperature of 80 ° C. or more exceeds 10% by weight, the low temperature heat sealability is not improved, and the foam cell height and uniformity at low temperatures may not be obtained.

(X4) Maximum peak temperature of elution temperature of cross fractionation chromatograph (CFC) In the present invention, it is important that the maximum peak temperature of elution temperature of (x4) cross fractionation chromatograph (CFC) is 70 ° C or less. is there. When the maximum peak temperature of the CFC elution temperature exceeds 70 ° C., the low-temperature heat sealability is not improved, and there is a possibility that the adhesive strength at low temperatures, the desired foam cell height, and uniformity may not be obtained. Arise.
The elution component amount and the maximum peak temperature can be adjusted mainly by the density of the ethylene-α-olefin copolymer, the distribution of the comonomer during the polymerization, etc., and these control methods are general and well known. .

(X5) Relationship between MFR and Memory Effect (ME) In the present invention, it is essential that (x5) MFR and the memory effect (ME) satisfy the following formula (1), and preferably the formula (1-1) More preferably, it is desirable to satisfy the formula (1-2).
−0.467 × Ln (MFR) + 2.75 ≦ ME −−−− (1)
(In the formula, Ln is a natural logarithm.)
Preferably,
−0.467 × Ln (MFR) + 2.77 ≦ ME −−−− (1-1)
More preferably,
−0.467 × Ln (MFR) + 2.79 ≦ ME −−−− (1-2)
If the memory effect (ME) is less than −0.467 × Ln (MFR) +2.75, the height of the foam cell does not increase, the neck-in during processing such as extrusion lamination increases, and the workability also increases. Since it becomes unstable, it is not preferable.

In the present invention, unless otherwise specified, the memory effect (ME) uses a melt indexer (semi-automatic ME meter manufactured by Misuzu Erie Co., Ltd.) used in JIS K7210, and the measurement conditions are a cylinder temperature of 240 ° C. and constant speed extrusion. It is measured as follows under the condition of an amount of 3 g / min.
A 2.095 mmφ MFR measuring nozzle is set in the apparatus, and the furnace is filled with resin. Place the piston, hold at 0.09 g / min constant speed extrusion for 5 minutes, then perform 3 g / min constant speed extrusion and release air until 6 minutes 30 seconds. After 6 minutes and 30 seconds, the strand was cut while maintaining 3 g / min. The diameter of the strand when the strand length from the lower end of the orifice became 20 mm was measured at 15 mm from the lower end of the orifice. Measure using a measuring instrument (LS-3033). ME is calculated | required by following Formula by making the diameter of the measured strand D and the orifice diameter of die | dye D0 (2.095 mm).
ME = D / D0

The blending ratio of the ethylene / α-olefin copolymer (A) and the high-pressure radical polyethylene resin (B) is (A) 90-50% by weight and (B) 10-50% by weight, preferably (A) 85-55 wt% / (B) 15-45 wt%, more preferably (A) 80-60 wt% / (B) 20-40 wt%.
When the resin (A) exceeds 90% by weight and the resin (B) is less than 10% by weight, or the resin (A) is less than 50% by weight and the resin (B) exceeds 50% by weight, Inconveniences such as inability to adjust various physical properties of the polyethylene resin material (X) occur, and as a result, the neck-in at the time of extrusion laminating is large, the stability at the time of processing deteriorates, and the purpose such as low-temperature foaming is not achieved. Since it occurs, it is not preferable.

  Polyethylene resin materials for foamable laminates are phenolic and phosphorous antioxidants, metal soaps and other neutralizers, antiblocking agents, lubricants, dispersants, pigments, as long as the object of the present invention is not impaired. Additives such as colorants such as dyes, antifogging agents, antistatic agents, ultraviolet absorbers, light stabilizers, and nucleating agents may be blended. In addition, other polyolefin resins such as linear low density polyethylene, medium / high density polyethylene, and polypropylene may be blended within a range not impairing the object of the present invention.

2 [Foaming laminate]
The polyethylene-based resin material (X) for the foamable laminate of the present invention is not only excellent in laminate performance (high-speed molding additivity, drawdown property, low neck-in, etc.) particularly when producing a laminate by lamination, Excellent foaming characteristics when producing heat-insulating materials such as paper cups. Further, when producing foamed paper, a heat insulating container and the like using a base material mainly composed of paper, a unique effect is exhibited.

  The laminate of the present invention is obtained from a polyethylene-based resin material (X) for a foamable laminate and a base material (I) mainly composed of paper, and the foamable laminate is formed on one surface of the base material mainly composed of paper. A polyethylene resin layer (II) formed using the body polyethylene resin material (X) is provided. Can be used as general processed paper, and by heating the laminate, the water contained in the base material mainly composed of paper can be evaporated to foam the polyethylene resin layer (II) (Hereinafter also referred to as foamable resin layer (II)).

  In the present specification, foaming refers to the property of foaming by heating. Good foaming refers to a state in which a high foaming ratio can be obtained mainly, water vapor generated mainly by heating of water contained in the paper base material, and foam cells in the thickness direction of the laminate. The height of the foam cell when growing is a measure. Also, the uniformity of the foam cell height is taken into account.

(1) Base material mainly composed of paper (I)
In the present invention, the base material (I) mainly composed of paper is one that can foam the polyethylene resin layer on the surface by a gas such as water vapor or volatile gas contained in the base material. There is no particular limitation. The base material (I) mainly composed of paper is (i) paper or (ii) a base material previously coated with a substance that generates volatile gas by heating, and paper and a polyethylene resin layer ( I) Means a substrate coated with a substance that generates a volatile gas by heating, and (iii) a substrate in which a substance that generates a volatile gas by heating is blended into a substrate mainly composed of paper.

  In the present invention, the polyethylene resin layer (II) on the substrate surface is foamed by the action of water vapor generated mainly by heating of water contained in the paper, but by the volatile gas generated by thermal decomposition, The material may be capable of foaming the polyethylene-based resin layer (II) on the surface of the substrate, and is not particularly limited.

Examples of the paper (i) include high-quality paper, craft paper, art paper, cup base paper, recycled paper, synthetic paper, sheets containing an inorganic substance such as resin and zeolite, and calcium carbonate. The basis weight of the paper is preferably 100 to 400 g / m ² , particularly 150 to 350 g / m ² . The water content of the paper is 3 to 15%, preferably 4 to 13%, more preferably about 4 to 12%.

  (Ii) Examples of the substrate coated with a substance that generates volatile gas by heat include a substrate coated with solvent-based ink, water-soluble ink, paint, and adhesive on paper, for example, As seen in Japanese Patent Application Laid-Open No. 2000-238225, etc., an adhesive layer to which a foamable substance is added is provided between the base material and the polyethylene resin layer (I), and the volatility generated from the foamable substance generated by heating. By the gas, it is possible to promote foaming of the polyethylene resin layer (II) on the substrate surface.

In addition, (iii) a substance that generates a volatile gas used in a base material mixed with a substance that generates a volatile gas by heating includes an inorganic or organic foaming agent, a water-containing polymer, a microcapsule encapsulating a foaming agent, and the like. For example, as seen in Japanese Patent Application Laid-Open No. 2002-145239 and the like, paper made by adding a heat-foaming foaming agent in the paper making process, or microcapsules encapsulating the foaming agent in paper, water-containing Examples thereof include a base material containing a water-absorbing polymer.
Furthermore, a picture, a character, a pattern, etc. can also be printed on paper, such as a pulp paper and a synthetic paper, with an ink etc. on the base material mainly made of paper.

(2) Polyethylene resin layer (II)
The polyethylene-based resin layer (II) according to the present invention is formed by laminating the polyethylene-based resin material (X) on at least one surface of a base material mainly made of paper by a usual laminating method, and mainly made of paper. In order to form a uniform foam cell having a high foaming ratio, the moisture contained mainly in the base material is evaporated and foamed by heating. The polyethylene-based resin material (X) for the foamable laminate Can be achieved by selecting the melting point within the range of 80 to 120 ° C., preferably within the range of about 90 to 110 ° C.

The thickness of the polyethylene-based resin layer (II) formed from the polyethylene-based resin material (X) for the foamable laminate is not particularly limited, but is 20 to 100 μm, and is 30 in that the thickness of the foamed layer is increased. ˜100 μm is preferred. If the thickness of the polyethylene-based resin layer (II) is less than 20 μm, there is a risk of bursting during foaming, and if it exceeds 100 μm, there is a possibility that the height of the foamed cells cannot be sufficiently increased.
Moreover, you may print on the polyethylene-type resin layer (II) used for this invention as needed. Printing may be partially printed with colored ink or may be printed entirely. For the printing position, the size of the printing area, the printing method, the ink used, etc., a conventionally known technique can be appropriately selected and used.

(3) Thermoplastic resin layer (III)
The thermoplastic resin layer (III) used in the foamable laminate of the present invention has a role of holding gas released from the substrate.
Here, holding gas etc. released from the base material means that gas such as water vapor, volatile gas, etc. released from the base material is diffused to the polyethylene resin layer (II) side, and the foamable polyethylene resin layer (II ) Refers to barriering gas such as water vapor and volatile gas so as to preferentially foam.
The thermoplastic resin layer (III) is composed of the thermoplastic resin (D) and has a melting point higher than that of the polyethylene resin forming the polyethylene resin layer (II), or any resin that does not melt. Not done. However, in order to preferentially foam the polyethylene resin layer (II) and easily obtain a uniform and high cell thickness, the polyethylene resin layer (II) foamed by water vapor or the like released from the substrate by heating. ) And the thermoplastic resin layer (III) that retains water vapor or the like released from the substrate, it is desirable that the following equation (4) be satisfied.
Tm (D) −Tm (X) ≧ 10 −−−−− Formula (4)
(However, Tm (X): melting point (° C.) of polyethylene resin of layer (II), Tm (D): melting point (° C.) of thermoplastic resin of layer (III))

  Examples of the thermoplastic resin (D) used in the present invention include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene-based resin, polybutene-1 resin, and poly-4-methyl- Alpha-olefin homopolymers having 2 to 10 carbon atoms such as pentene-1 resin, or polyolefin resins such as their intercopolymers, polyamide resins, polyester resins, saponified ethylene-vinyl acetate copolymers, chlorides Examples thereof include vinyl resins, vinylidene chloride resins, polystyrene resins, and mixtures thereof. Among these, polyolefin resins such as high density polyethylene, medium density polyethylene, and linear low density polyethylene are preferable.

When a polyolefin resin is employed as the thermoplastic resin (D), the MFR is 0.1 to 100 g / 10 minutes, preferably 0.3 to 80 g / 10 minutes, more preferably 0.5 to 60 g / 10. Minutes and densities of 0.920 to 0.970 g / cm ³ , preferably 0.925 to 0.960 g / cm ³ , more preferably about 0.930 to 0.950 g / cm ³ are preferable.
In consideration of the polyolefin resin layer (II), the melting point Tm (III) is selected in the range of 100 ° C. or higher, preferably 100 to 140 ° C., more preferably 110 to 140 ° C., and still more preferably 115 to 140 ° C. It is desirable that Here, the melting point Tm (III) is a melting point of the highest peak height in the second scanning melting point measured by DSC.
If the melting point is lower than 100 ° C., the heat resistance may be insufficient and the thermoplastic resin layer may foam, and if it exceeds 140 ° C., the low-temperature heat sealability may be poor.

  In addition, in the case of using a resin having poor adhesion to the paper substrate such as polyamide resin, polyester resin, saponified ethylene-vinyl acetate copolymer, vinyl chloride resin, vinylidene chloride resin, polystyrene resin, It is good also as a laminated body through usual adhesive resin etc., such as a copolymer with unsaturated carboxylic acid modified polyolefin resin and ethylene-unsaturated carboxylic acid.

  The thickness of the thermoplastic resin layer (III) is not particularly limited, but is usually selected in the range of 10 to 300 μm, particularly 10 to 200 μm, more preferably 10 to 150 μm in that the thickness of the foamed layer can be increased. It is preferred that If the thickness of the thermoplastic resin layer (III) is less than 10 μm, vapor or the like released from the substrate cannot be sufficiently retained, and the foam layer may not be sufficiently thick. On the other hand, if it exceeds 300 μm, further improvement in the effect is not expected, and there is a possibility that economic disadvantages will increase.

(4) Layer structure of foamable laminate In the foamable laminate of the present invention, other layers may be provided in the interlayer, or the inner layer and / or the outer layer, etc., as long as the object of the present invention is not impaired. . For example, {polyethylene film layer / foamable resin layer (II) / base material (I) / thermoplastic resin layer (III)}, {polyethylene film layer / barrier layer / adhesive layer / foamable resin layer (II) ) / Base material (I) / thermoplastic resin layer (III)}, {foamable resin layer (II) / base material (I) / barrier layer / thermoplastic resin layer (III)}, {foamable resin layer ( II) / base material (I) / thermoplastic resin layer (III) / barrier layer / thermoplastic resin layer (III)}, and the thermoplastic resin. An inner layer and / or an outer layer of the laminate provided with the layer (III), or one or more film layers, a decorative layer, a reinforcing layer, an adhesive layer, a barrier layer, or the like may be provided between the layers.
Moreover, you may print etc. as needed. The printing may be performed partially or entirely with colored ink. Moreover, you may provide a foaming site | part partially or entirely using a foamable ink as needed. For the printing position, the size of the printing area, the printing method, the ink used, etc., a conventionally known technique can be appropriately selected and used.

Examples of the decorative layer include printed paper, film, nonwoven fabric, and woven fabric.
The reinforcing layer is a polyethylene resin film or the like on the outer layer of the polyolefin resin layer (A) so that the foamed layer does not rupture when the polyolefin resin layer (A) laminated on the substrate is foamed by heating. It plays the role of preventing the explosion due to excessive foaming of the foamed layer, correcting uneven foam cells uniformly, or laminating films, nonwoven fabrics, etc. to give mechanical strength. The resin is not particularly limited, and may be a polyolefin resin such as polyethylene or polypropylene, a polyamide resin, a polyester resin, or the like.
Examples of the resin forming the adhesive layer include a copolymer of ethylene and an unsaturated carboxylic acid or a derivative thereof, a modified polyolefin resin obtained by grafting an unsaturated carboxylic acid on a polyolefin resin, an ethylene-vinyl acetate copolymer, etc. A hot melt, a normal adhesive, etc. are mentioned.
As the resin for forming the barrier layer, polyamide resin, polyester resin, ethylene-vinyl acetate copolymer saponified product (EVOH), polyvinylidene chloride resin, polycarbonate resin, stretched polypropylene (OPP), stretched polyester ( OPET), stretched polyamide, alumina vapor deposition film, inorganic oxide vapor deposition film such as silica vapor deposition film, metal vapor deposition film such as aluminum vapor deposition, and metal foil.

  In order to produce the foamable laminate of the present invention, any method that can laminate the polyolefin resin layer (II) and the thermoplastic resin layer (III) on both surfaces of a paper-based substrate can be employed, and particularly limited. However, there are an extrusion laminating process in which a molten resin is directly laminated, a coextrusion laminating method, a sand laminating process in which a film is previously laminated, a dry laminating method, and the like.

Extrusion laminating is a molding method in which a molten resin film extruded from a T-die is continuously coated and pressure-bonded on a substrate, and coating and adhesion are performed simultaneously. Sand laminating is a method in which a molten resin is poured between paper and a film to be laminated, and the molten resin acts as an adhesive to bond and laminate. Dehumidify the ambient humidity in the vicinity of the adhesive and / or adhesive application roll that bonds the film to be laminated with, or heat the temperature of the adhesive and / or adhesive application roll, or paste the film sheet This is a method of drying the surface.
In the sand laminating process and the dry laminating process, on the side where the thermoplastic resin layer (B) of the base material mainly composed of paper used in the present invention is formed, between the base material and the thermoplastic resin layer (B). In order to improve the barrier property, it is easy to laminate aluminum foil, polyester film, various barrier films and the like.

3 [foamed paper]
The foamed paper of the present invention is obtained by heating the foamable laminate and foaming the foamable resin layer (A). The height of the foamed cell of the foamed paper is desirably 300 μm or more, preferably 350 μm or more. If the height of the foamed cell is less than 300 μm, there is a possibility that sufficient heat insulating properties cannot be obtained.

The heating method is not particularly limited, and examples include hot air, microwave, high frequency, infrared, far infrared. Although there is no restriction | limiting in particular in heating temperature, It should be the temperature which evaporates the water | moisture content in paper and a foamable resin fuse | melts, for example, 100-200 degreeC, Preferably it is 100-160 degreeC, More preferably, it is 100- 140 ° C. is preferred. The heating time is preferably 10 seconds to 5 minutes. If the heating temperature is less than 100 ° C. and the heating time is less than 10 seconds, a sufficient foamed cell height may not be obtained. When the heating temperature exceeds 200 ° C. or the heating time exceeds 5 minutes, the sag and uniformity of the foamed cell may be impaired.
The foamed paper is not only used as a heat insulating and heat insulating material for heat insulating containers such as the following cups, but also used as a buffer material, sound insulating material, foamed paper, etc., sleeve material, paper plate, tray, anti-slip material, It is used as a packaging material for fruits, agricultural paper such as foamed paper, industrial materials, and daily life materials.

4 [Insulated container]
The heat insulating container of the present invention is obtained by forming a container using the foamable laminate and then heating the container to foam the polyethylene resin layer (II).
Even in the heat insulating container, like the foamed paper, the height of the foamed cell is preferably 300 μm or more, and more preferably 350 μm or more. If the height of the foamed cell is less than 300 μm, there is a possibility that sufficient heat insulating properties cannot be obtained.
The insulated container obtained by this is used as a tray, a cup, etc. Applications include hot beverage containers, cup soup containers, cup miso soup containers, cup noodle containers, natto containers, bento containers, coffee cup containers, microwave oven-compatible containers, and the like.

5 [Production method of heat insulation container]
The manufacturing method of the heat insulating container, particularly the cup, is based on at least a base material (I) mainly composed of paper and water vapor released from the base material by heating on one surface of the base material mainly composed of the paper. A polyethylene resin layer (II) having a thickness of 20 to 100 μm is formed using the foamed polyethylene resin material (X), and a thermoplastic resin (D) is used on the other surface of the substrate. A foamable laminate formed with a thermoplastic resin layer (III) having a thickness of 10 to 300 μm that retains water vapor released from the container is formed, and then molded into a container and then heated at a heating temperature of 100 to 200 ° C. Then, the polyethylene resin layer (II) is foamed by water vapor or the like released from the base material.
The method for manufacturing a heat insulating container is basically the same as the method for manufacturing foamed paper. For laminating the base material (I), a usual laminating method is applied. In the extrusion lamination, the resin temperature immediately below the die is 200 to 350 ° C, preferably 260 to 350 ° C, more preferably 270 to 350 ° C. The molding speed is 10 to 400 m / min, preferably about 10 to 350 m / min, and if necessary, in order to improve the adhesion between the base material and the polyethylene resin, corona discharge treatment, ozone treatment, Plasma treatment, flame treatment, or the like may be performed. Moreover, you may apply | coat an anchor coating agent as needed.
The foamed laminate produced in this way is rolled out or continuously drawn out, and a blank for a trunk member and a blank for a bottom plate member are punched out from the foamed laminate, and a barrel member is used with a conventional cup molding machine. After the bottom plate members are joined and molded into a cup shape, etc., they are transported to a batch or transfer belt conveyor and heated and foamed in a furnace, oven tunnel, etc. equipped with hot air, microwave, high frequency, infrared, far infrared, etc. A heat insulating container is formed.
In particular, for continuous production, preferably, a polyethylene resin layer (II) foamed by water vapor or the like released from the base material by heating, and a thermoplastic resin holding the water vapor or the like released from the base material It is desirable that the melting point difference with the layer (III) satisfies the relationship of the following formula (4).
Tm (D) −Tm (X) ≧ 10 −−−−− Formula (4)
(However, Tm (X): Melting point Tm (° C.) of polyethylene resin of layer (II), Tm (D): Melting point Tm (° C. of layer (III) thermoplastic resin for holding vapor etc. in substrate) )
As a result, high-speed moldability such as extrusion lamination is good, it is possible to continuously form a foam layer having a high foaming ratio and uniform foam cells, good appearance, good printability and productivity. improves. The heating time is preferably 10 seconds to 5 minutes. If the heating temperature is less than 100 ° C. and the heating time is less than 10 seconds, a sufficient foamed cell height may not be obtained. In addition, when the heating temperature exceeds 200 ° C. and / or the heating time exceeds 5 minutes, the generated foamed cell becomes excessively heated, causing the foamed cell to sag and the like, resulting in product variations. There is a fear.
As described above, in the production method of the present invention, by using the specific polyethylene resin material (X), the moldability at the time of extrusion lamination, the loss is small, the foaming ratio is high, and a uniform foam cell is obtained. It becomes the formed foamed layer, and a heat insulating container excellent in heat insulating properties, good appearance and the like can be easily obtained.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In addition, test methods, such as the polyethylene-type resin material (X) manufactured in a present Example, its physical property, and the obtained foaming laminated body, are as follows.

1. Test method (1) MFR: Measured according to JIS K7210 (190 ° C., 21.18 N load).
(2) Density: The pellets were hot-pressed to prepare a press sheet having a thickness of 2 mm. The sheet was placed in a beaker having a capacity of 1000 ml, filled with distilled water, covered with a watch glass, and heated with a mantle heater. After boiling boiling water for 60 minutes, the beaker was placed on a wooden table and allowed to cool. At this time, the boiling distilled water after boiling for 60 minutes was adjusted to 500 ml so that the time until reaching room temperature was not less than 60 minutes. Moreover, the test sheet was immersed in the substantially center part in water so that it might not contact a beaker and the water surface. The sheet was annealed at a temperature of 23 ° C. and a humidity of 50% within a period of 16 hours or more and within 24 hours, then punched out to a length of 2 mm and measured at a test temperature of 23 ° C. according to JIS-K7112.

(3) Cross fractionation chromatograph (CFC):
After completely dissolving the polymer sample in orthodichlorobenzene (ODCB) containing 0.5 mg / mL BHT at 140 ° C., this solution was passed through a sample loop of the apparatus, and the TREF column (inert glass beads) held at 140 ° C. Column) packed with a carrier, and gradually cooled to a predetermined first elution temperature to crystallize the polymer sample. After maintaining at a predetermined temperature for 30 minutes, ODCB is passed through a TREF column, whereby the eluted component is injected into the GPC section to perform molecular weight fractionation, and an infrared detector (MIRAN 1A IR detector manufactured by FOXBORO, A chromatogram is obtained with a measuring wavelength of 3.42 μm). Meanwhile, in the TREF part, the temperature is raised to the next elution temperature, and after obtaining the chromatogram of the first elution temperature, the elution component at the second elution temperature is injected into the GPC part. Thereafter, the same operation is repeated to obtain a chromatogram of the eluted components at each elution temperature.
<Measurement conditions>
Equipment: CFC-T102L manufactured by Dia Instruments
GPC column: Showa Denko AD-806MS (3 connected in series)
Solvent: ODCB
Sample concentration: 3 mg / mL
Injection volume: 0.4mL
Crystallization rate: 1 ° C / min
Solvent flow rate: 1 mL / min GPC measurement time: 34 minutes Stabilization time after GPC measurement: 5 minutes Elution temperature:
LLDPE: linear low density polyethylene 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120, 140
HPLDPE: high pressure radical polymerization method low density polyethylene 0, 10, 20, 30, 35, 40, 45, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88 , 91, 100, 120, 140
<Data analysis>
The chromatograms of the eluted components at each elution temperature obtained by the measurement are processed by the data processing program attached to the device, and the standardized elution amount (proportional to the area of the chromatogram) is obtained so that the total is 100%. It is done. In addition, an integrated elution curve for the elution temperature is calculated. The integrated elution curve is differentiated with temperature to obtain a differential elution curve. Moreover, molecular weight distribution is calculated | required by the following procedure from each chromatogram. Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene. Standard polystyrenes used are the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.
A calibration curve is created by injecting 0.4 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method. Conversion to molecular weight uses a general-purpose calibration curve with reference to “Size Exclusion Chromatography” written by Sadao Mori (Kyoritsu Shuppan). The following numerical value is used for the viscosity formula [η] = K × Mα used in that case.
PS K = 1.38 × 10−4, α = 0.7
PE K = 3.92 × 10 −4, α = 0.733
PP K = 1.03 × 10−4, α = 0.78
In the chromatogram at the first elution temperature, the peak due to BHT added to the solvent may overlap with the low molecular weight side of the eluted component. In this case, the baseline is drawn as shown in FIG. 1 to obtain the molecular weight distribution. Define the section.

(4) Memory effect (ME): Measured using a semi-automatic ME meter manufactured by Misuzu Erie. The melt indexer used in JIS K7210 was used, and the measurement conditions were as follows under the conditions of a cylinder temperature of 240 ° C. and a constant speed extrusion rate of 3 g / min.
A 2.095 mmφ MFR measuring nozzle is set in the apparatus, and the furnace is filled with resin. Place the piston, hold at 0.09 g / min constant speed extrusion for 5 minutes, then perform 3 g / min constant speed extrusion and release air until 6 minutes 30 seconds. After 6 minutes and 30 seconds, the strand was cut while maintaining 3 g / min. The diameter of the strand when the strand length from the lower end of the orifice became 20 mm was measured at 15 mm from the lower end of the orifice. Measure using a measuring instrument (LS-3033). Was determined ME by the following equation the measured diameter of the strand D, and the orifice diameter of the die as _D 0 _(2.095mm).
ME = D / D ₀

(5) Melting point: A pellet was formed into a sheet by hot pressing, and punched out to obtain a sample. The measurement was carried out under the following conditions under the procedure of first temperature rise, temperature drop, and second temperature rise, and the temperature at the maximum peak height of the second temperature rise was taken as the melting point.
Apparatus: DSC220 manufactured by Seiko Instruments Inc.
Temperature raising / lowering conditions: First temperature rise from 30 ° C to 200 ° C at 40 ° C / min
Temperature drop 10 ° C / min from 200 ° C to 20 ° C
Second temperature increase from 20 ° C. to 200 ° C. at 10 ° C./min Temperature holding time: 5 minutes after first temperature increase, 5 minutes after temperature decrease Sample amount: 5 mg
Reference: Aluminum

(6) Processability: When polyethylene resin (X) was extrusion laminated, it was visually evaluated whether processing could be performed stably.
○: The molten film is stable and can be processed.
X: The molten film is unstable and it is impossible to collect a sample having a uniform thickness.

(7) Low-temperature heat-sealing properties Combine the polyolefin resin material layer (I) surface and the thermoplastic resin layer (D) surface of the foam laminate, heat sealer (only the upper part is a heat seal bar, the lower part is a rubber set at 30 ° C) The temperature was increased from 85 ° C. in increments of 5 ° C., and pressure was applied at 2 kg / cm ² pressure for 2 seconds at each temperature to perform heat sealing.
The obtained heat seal laminate was pulled in a T shape at a speed of 500 mm / min with a tensile tester, and the heat seal strength was measured. From the obtained heat seal strength curve, the temperature at which the heat seal strength was 2 N / 15 mm was determined.

(8) Foaming property: The cross section of the foamed laminate was magnified 50 times with a microscope, the thickness of the foamed layer was measured, and the foamed cell height was obtained.

(9) Uniformity of foamed cells: The surface of the foamed laminate was visually observed to evaluate the presence and uniformity of partial excessive foaming.
○: Good, Δ: Cell height is uneven, ×: Cell rupture occurs.

[Raw resin]
1. Production of ethylene-α-olefin copolymer (A) (production of ethylene-α-olefin copolymer (A1))
[Production Example 1]
To a complex of ethylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride (2.0 mmol), methylaluminoxane manufactured by Toyo Stofer was added 1000 mol times the above complex, and diluted to 10 liters with toluene. A catalyst solution was prepared. This catalyst solution was put into a 1.5-liter stirred autoclave continuous reactor, and a mixture of ethylene, propylene and 1-hexene was further added into this reactor in the form of ethylene / propylene / 1-hexene = 70/21. / 9 (weight%) was supplied, the pressure in the reactor was kept at 800 kg / cm ² , and the reaction was performed at 220 ° C. After completion of the reaction, the MFR was 30 g / 10 min, the density was 0.907 g / cm ³ , the Mw / Mn was 2.1, the propylene molar fraction was 5.3 mol%, and the 1-hexene molar fraction was 1. 9 mol%, ethylene / propylene / 1-hexene terpolymer (A1) having a ratio Mp / Mh of 2.8 molar ratio of propylene (Mp) to 1-hexene (Mh) Got. The properties of the obtained polymer are shown in Table 1.

(Production of ethylene-α-olefin copolymer (A2))
[Production Example 2]
In Production Example 1, polymerization was carried out under the same conditions as in Production Example 1 except that propylene was not fed and the ethylene / 1-hexene feed ratio was changed, and the reaction temperature and reaction pressure were adjusted. An ethylene / 1-hexene copolymer (A2) was obtained. The properties of the obtained polymer are shown in Table 1.

(Production of ethylene-α-olefin copolymer (A3))
[Production Example 3]
In Production Example 1, polymerization was carried out under the same conditions as in Production Example 1 except that propylene was not fed and the ethylene / 1-hexene feed amount ratio was changed and the reaction temperature and reaction pressure were adjusted. -A 1-hexene copolymer (A3) was obtained. The properties of the obtained polymer are shown in Table 1.

(Ethylene-α-olefin copolymer by metallocene catalyst (A4))
MFR 11 g / 10 min, density 0.921 g / cm ³ , ME 1.2 Tm 122 ° C.

2. High pressure radical polymerization polyethylene resin (B)
B1: MFR 8 g / 10 min, density 0.918 g / cm ³ , ME 2.1 Tm 106 ° C.

3. Thermoplastic resin (D)
Medium density polyethylene resin (Nippon Polyethylene Corporation, trade name: HC170)
MFR 10 g / 10 min, density 0.936 g / cm ³ , Tm (D) 129 ° C.

Example 1
One side of a paper substrate having a basis weight of 157 g / m ² and a moisture content of 7% is subjected to corona treatment (30 W · min / m ² ), and a thermoplastic resin layer (extruding laminator with a 40Φ extruder and a die effective width of 360 mm is used) As a material constituting D), the above medium density polyethylene resin is extruded and laminated at a resin temperature of 320 ° C., a processing speed of 20 m / min, and a thickness of 20 μm, and a laminate of the thermoplastic resin layer (III) and a paper substrate is obtained. Obtained.
Next, the paper substrate surface opposite to the thermoplastic resin layer (III) of the laminate is subjected to corona treatment (30 W · min / m ² ), and the resin is obtained using a 40Φ extruder and an extrusion laminator having a die effective width of 360 mm. The polyethylene resin material (X1) obtained above is extruded and laminated as a material constituting the polyolefin resin material layer (II) at a temperature of 320 ° C., a processing speed of 20 m / min, and a thickness of 40 μm. A foamable laminate comprising (II), a paper substrate and a thermoplastic resin layer (III) was obtained.
The obtained foamable laminate was left in an oven at 113 ° C. for 2 minutes, then taken out of the oven and allowed to cool at room temperature to obtain foamed paper. The results are shown in Table 1. The foamed cell height of this foamed paper was 380 μm. The results are shown in Table 2.

(Examples 2-3)
It replaced with the polyethylene resin material (X1) of the said Example 1, and carried out similarly to Example 1 except having used the polyethylene resin material (X2) or (X3), and obtained the foaming laminated body and the foaming processed paper. . The results are shown in Table 2.

(Comparative Example 1)
It replaced with the polyethylene resin material (X1) of Example 1, and carried out similarly to Example 1 except having used the ethylene-alpha-olefin copolymer (A2) independently. As a result, the ethylene-α-olefin copolymer (A2) did not satisfy the formula (1) of the present invention, had poor moldability, could not be laminated, and could not produce a sample. The evaluation results are shown in Table 2.

(Comparative Example 2)
It replaced with the polyethylene resin material (X1) of Example 1, and performed similarly to Example 1 except having used the high pressure radical polymerization method low density polyethylene resin (B1) independently.
As a result, the low temperature heat sealability and the foamed cell were not sufficient. The evaluation results are shown in Table 2.

(Comparative Example 3)
It carried out like Example 1 except having replaced with the polyethylene resin material (X1) of Example 1, and having used the polyethylene resin material (X4). As a result, the low-temperature heat sealability was poor, and the foamed cells were not sufficient. The evaluation results are shown in Table 2.

Claims (11)

At least a base material (I) mainly composed of paper and a polyethylene-based resin layer (II) foamed by a gas released from the base material by heating on one surface of the base material mainly composed of the paper A polyethylene-based resin material (X) for a foamable laminate,
The ethylene-α-olefin copolymer (A) having the following properties (a1) and (a2): more than 50% by weight and 90% by weight or less, and 10% by weight to 50% by weight of the high-pressure radical polymerization polyethylene resin (B) A polyethylene-based resin material for a foamable laminate, which is obtained by blending less than 1% and has the following properties (x1) to (x5).
(A1) Melt flow rate (MFR) measured in accordance with JIS K7210 is 1 to 50 g / 10 min,
(A2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 to 0.935 g / cm ³ .
(X1) Melt flow rate (MFR) measured in accordance with JIS K7210 is 1 to 30 g / 10 min,
(X2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.880 g / cm ³ or more,
(X3) The amount of elution components at an elution temperature of 80 ° C. or higher by a cross fractionation chromatograph (CFC) is 10% by weight or less,
(X4) The maximum peak temperature of elution temperature by cross fractionation chromatograph (CFC) is 70 ° C. or less,
(X5) MFR and memory effect (ME) satisfy the following formula (1).
−0.467 × Ln (MFR) + 2.75 ≦ ME (1)
(In the formula, Ln is a natural logarithm.)   The polyethylene-based resin material for a foamable laminate according to claim 1, wherein the ethylene-α-olefin copolymer (A) is a resin produced using a single-site catalyst. The polyethylene for a foamable laminate according to claim 1 or 2, wherein the high-pressure radical polymerization polyethylene resin (B) is a low-density polyethylene resin that satisfies the following properties (b1) to (b2): Resin material.
(B1) The MFR measured according to JIS K7210 is 1 to 30 g / 10 min.
(B2) The density measured according to the test temperature of 23 ° C. and JIS K7112 is 0.910 to 0.940 g / cm ³ . The high-pressure radical polymerization polyethylene resin (B) is a low-density polyethylene resin (B11) that satisfies the following properties (b1) to (b2) and a low-density polyethylene that satisfies the following properties (b3) to (b5): The polyethylene resin material for foamable lamination according to any one of claims 1 to 3, wherein the polyethylene resin material is a high-pressure radical polymerization low-density polyethylene resin in which at least two kinds of resins (B12) are mixed.
(B1) MFR measured according to JIS K7210 is 1 to 30 g / 10 min.
(B2) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.910 to 0.935 / cm ³ .
(B3) MFR measured according to JIS K7210 is 0.1 to 100 g / 10 min.
(B4) The test temperature is 23 ° C., and the density measured according to JIS K7112 is 0.910 to 0.940 g / cm ³ .
(B5) A memory effect (ME) measured using a melt indexer used in JIS K7210 under the conditions of a cylinder temperature of 240 ° C. and a constant speed extrusion rate of 3 g / min is 1.5 or more.   Foamability formed by forming a polyethylene resin layer (II) comprising the polyethylene resin material (X) according to any one of claims 1 to 4 on one surface of a base material (I) mainly comprising paper. Laminated body.   Furthermore, the thermoplastic resin layer (III) made of the thermoplastic resin (D) that holds the gas released from the base material (I) was formed on the other surface of the base material (I) mainly composed of paper. The foamable laminate according to claim 5.   Foamed paper obtained by heating the foamable laminate according to claim 5 or 6 to foam the polyethylene resin layer (II).   The foamed paper according to claim 7, wherein the foamed cell formed by foaming the polyethylene resin layer (II) has a height of 300 μm or more.   A heat insulating container obtained by forming a container using the foamable laminate according to claim 5 or 6 and then heating the container to foam the polyethylene resin layer (II).   The heat insulation container according to claim 9, wherein the heat insulation container is a cup-shaped container.   A polyethylene-based resin layer (II) is formed on one surface of a base material (I) mainly composed of paper, using the polyethylene-based resin material for foaming lamination according to claim 1, and if necessary, paper is used. A thermoplastic resin layer (III) made of a thermoplastic resin (D) that holds the gas released from the base material (I) is formed on the other surface of the base material (I) as a main component, and foamable. After obtaining the laminate, this is molded into a container, and subsequently heated to a temperature of 100 to 200 ° C., and the polyethylene resin layer (II) is formed by the gas released from the base material (I) mainly composed of paper. A method for producing a heat-insulating container, comprising foaming.

Images