JP2016078351A - Foam laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam laminate that exhibits an excellent insulation property and foam exterior appearance, and is excellent in economy.SOLUTION: Provided is a foam laminate comprising at least a layer (A)/a paper substrate layer/a layer (B) and in which the layer (A) is a foam layer, and in which the layer (A) is composed of a high pressure process low density polyethylene (a) having a density measured in accordance with JIS K6922-1 (year 2010) of 910 kg/mor more and 930 kg/mor less, and the layer (B) is composed of a polyethylene-based resin (b) having a density measured in accordance with JIS K6922-1 (year 2010) of 935 kg/mor more and 970 kg/mor less; and the following (i) to (iii) are satisfied. (i) the ratio of a thickness (μm) of layer (A) after the foaming to a basis weight (g/m) of the paper substrate is 2.5 or more and 5.0 or less; (ii) the basis weight (g/m) of the paper substrate is 160 or more and 260 or less; and (iii) the moisture content in the paper substrate after laminating the high pressure process low density polyethylene (a) and the polyethylene-based resin (b) is 14 g/mor more and less than 22 g/m.SELECTED DRAWING: None

Description

  The present invention relates to a foamed laminate having a large thickness of a foamed layer, exhibiting good heat insulating properties and foamed appearance, and being excellent in economic efficiency.

  Conventionally, as a container having a heat insulating property, a synthetic resin, in particular, a polystyrene foamed one is often used. However, the expanded polystyrene container has drawbacks such as high environmental load at the time of disposal and poor printability, and alternatives to other materials are being studied. Under such circumstances, a container in which corrugated paper is pasted on the outer peripheral surface of the paper cup body to form a heat insulating layer, a container in which a laminate of pulp nonwoven fabric and coated paper is bonded to the outer peripheral surface of the paper cup, etc. Has been developed and used.

  However, each method has a drawback that it is not easy to process and mold, and the cost is high. Therefore, by laminating and heating a low-melting-point thermoplastic synthetic resin film on at least one surface of the moisture-containing base material, the synthetic resin film is foamed into irregularities using the moisture contained in the base material. Has been devised (see, for example, Patent Documents 1 to 3). However, the material thus obtained has a thin foam layer and insufficient heat insulation.

  Further, the container body member and the bottom plate member are composed of a high-melting point thermoplastic synthetic resin film laminated on the inner wall surface of the base material of the container body member and the bottom plate member, and low density polyethylene is formed on the outer wall surface of the base material of the container body member. A heat insulating paper container is proposed in which a resin composition film obtained by mixing an ethylene / α-olefin copolymer is laminated, and the resin composition film is foamed by heat treatment (for example, Patent Documents). 4).

  However, in the heat insulating paper container using the resin composition film formed by mixing low density polyethylene and ethylene / α-olefin copolymer on the outer wall surface, the smoothness of the foam layer surface is poor and the foam appearance is poor. .

Japanese Patent Publication No. 48-32283 JP-A-57-110439 JP 2001-270571 A Japanese Patent Laid-Open No. 2007-217024

  An object of the present invention is to provide a foamed laminate having a large foamed layer, exhibiting good heat insulation and foam appearance, and being excellent in economic efficiency.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific foam laminate exhibits excellent heat insulation and foam appearance, and is excellent in economy, and has completed the present invention. It was.

That is, at least (A) layer / paper substrate / (B) layer, and (A) layer is a foamed laminate, and (A) layer is in accordance with JIS K6922-1 (2010). measured density is 910 kg / ^{m 3} or more 930 kg / ^{m 3} or less is high-pressure low-density polyethylene (a), (B) layer is JIS K6922-1 density measured by (2010) is 935 kg / ^{m 3} or more The foamed laminate is composed of a polyethylene resin (b) that is 970 kg / m ³ or less and satisfies the following (i) to (iii).

(I) The ratio of the thickness (μm) of the foamed (A) layer to the basis weight (g / m ² ) of the paper substrate is 2.5 or more and 5.0 or less.

(Ii) The basis weight (g / m ² ) of the paper substrate is 160 or more and 260 or less.

(Iii) The water content of the paper base material after laminating the high-pressure method low-density polyethylene (a) and the polyethylene-based resin (b) is 14 g / m ² or more and less than 22 g / m ² .

  Hereinafter, the present invention will be described in detail.

  The high pressure low density polyethylene (a) constituting the laminate of the present invention can be obtained by a conventionally known high pressure method radical polymerization method.

The density (hereinafter simply abbreviated as density) measured by JIS K6922-1 (2010) of the high-pressure method low-density polyethylene (a) is excellent in heat insulating properties and foamed appearance, and is in the range of 910 to 930 kg / m ³ . More preferably 914 to 926 kg / m ³ , and still more preferably 916 to 924 kg / m ³ . When the density of the high-pressure method low-density polyethylene (a) is less than 910 kg / m ^3, it is not preferable because it is inferior in foamed appearance, and in the range exceeding 930 kg / m ³ , it is not preferable because it is inferior in heat insulation.

  The melt mass flow rate (hereinafter simply abbreviated as MFR) measured by JIS K6922-1 (2010) of the high pressure method low density polyethylene (a) is 10 to 30 g / 10 min. In addition, it is preferable because of its excellent foam appearance, more preferably in the range of 12-30 g / 10 min, still more preferably 13-24 g / 10 min, and most preferably 13-18 g / 10 min.

  You may mix | blend other polyolefins, such as an ethylene-alpha-olefin copolymer, with the high pressure method low density polyethylene (a) which comprises this invention.

  When the polyolefin is mixed with the high-pressure method low-density polyethylene (a) constituting the laminate of the present invention, the pellet mixture obtained by mixing the pellets of the high-pressure method low-density polyethylene (a) and the polyolefin pellets in a solid state. Although a mixture obtained by melt-kneading with a single screw extruder, twin screw extruder, kneader, Banbury or the like is preferable, a product with stable quality can be obtained. When using a melt kneader, the melting temperature is preferably about the melting point of the polyolefin resin to about 300 ° C.

  In addition, the high-pressure low-density polyethylene (a) constituting the laminate of the present invention is generally used for polyolefin resins such as an antioxidant, a light stabilizer, an antistatic agent, a lubricant, and an antiblocking agent as necessary. The additives that have been used may be added within a range that does not impair the object of the present invention.

Density of the polyethylene resin (b) constituting the laminate of the present invention, thermal insulation, due to excellent stability of the foam is in the range of 935~970kg / ^{m 3,} more preferably 945~970kg / ^{m 3} Most preferably, it is 950 to 965 kg / m ³ . When the density of the polyethylene resin (b) is less than 935 kg / m ^3, it is not preferable because the heat insulation is poor, and when it exceeds 970 kg / m ³ , it is not preferable because the foam appearance is poor.

  The polyethylene resin (b) constituting the laminate of the present invention is an ethylene homopolymer, an ethylene / α-olefin copolymer or a composition thereof, and the molecular chain may be linear, It may have a long chain branch having 6 or more carbon atoms. Such a polyethylene-based resin (b) is not particularly limited, and it is sufficient that the density range is not exceeded.

  Examples of the ethylene homopolymer include low-pressure ethylene homopolymer and high-pressure low-density polyethylene. The low-pressure ethylene homopolymer can be obtained by a conventionally known low-pressure ion polymerization method. The high pressure method low density polyethylene can be obtained by a conventionally known high pressure radical polymerization method.

  Examples of the α-olefin used in the ethylene / α-olefin copolymer include propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene and the like can be mentioned, and one or more of these can be used.

  A method for obtaining such an ethylene / α-olefin copolymer is not particularly limited, and examples thereof include a high / medium / low pressure ion polymerization method using a Ziegler-Natta catalyst, a Philips catalyst, or a metallocene catalyst. Can do. Such a copolymer can be conveniently selected from commercially available products.

  Since the polyethylene resin (a) is excellent in laminate moldability, an ethylene resin composition (e) comprising 10 to 90% by weight of high density polyethylene (c) and 90 to 10% by weight of high pressure method low density polyethylene (d). ) Is preferable.

  Examples of the high-density polyethylene (c) include a low-pressure ethylene homopolymer and an ethylene / α-olefin copolymer.

  In the high-density polyethylene (c), the MFR is preferably in the range of 6 to 100 g / 10 minutes, more preferably in the range of 8 to 60 g / 10 minutes because of excellent laminating properties of the ethylene-based resin composition (e). is there.

Further, in the high density polyethylene (c), the ethylene resin composition (e) is excellent in laminate processability and productivity, so that the density is preferably in the range of 935 to 980 kg / m ³ , more preferably 945 to 975 kg / m. ³ range.

  In such a high pressure method low density polyethylene (d), since the extrusion laminating property of the ethylene resin composition (e) is excellent, the MFR is preferably in the range of 0.1 to 20 g / 10 min, more preferably 0.8. It is in the range of 3 to 10 g / 10 minutes, most preferably 1 to 4 g / 10 minutes.

Moreover, in such a high-pressure method low-density polyethylene (d), since the film-forming stability of the ethylene-based resin composition (e) is excellent, the density is preferably in the range of 910 to 935 kg / m ³ .

  Since MFR of such an ethylene resin composition (e) is excellent in laminate moldability, it is preferably in the range of 1 to 50 g / 10 minutes, more preferably in the range of 3 to 20 g / 10 minutes.

  Further, the polyolefin resin (b) constituting the present invention may be blended with other polyolefins such as polypropylene, and the blending ratio of these polyolefins is 1 to 30% by weight of laminate moldability and laminate appearance. It is preferable from the point.

  When the polyolefin is mixed with the polyethylene resin (b) constituting the laminate of the present invention, it may be a pellet mixture in which the pellets of the polyethylene resin (b) and the polyolefin pellets are mixed in a solid state. A mixture obtained by melt kneading with a screw extruder, twin screw extruder, kneader, Banbury or the like is preferable because a product with stable quality can be obtained. When using a melt-kneading apparatus, the melting temperature is preferably about the melting point of polyethylene resin to about 300 ° C.

  Furthermore, for the polyethylene resin (b) constituting the present invention, additives generally used for polyolefin resins, such as an antioxidant, a light stabilizer, an antistatic agent, a lubricant, and an antiblocking agent, as necessary. May be added as long as the object of the present invention is not impaired.

  The thickness before foaming of the layer (A) constituting the laminate of the present invention is not particularly limited as long as the object of the present invention is achieved, but is preferably in the range of 30 to 70 μm because of excellent foam appearance. More preferably, it is 35-65 micrometers, Most preferably, it is 40-60 micrometers.

  The thickness of the (B) layer is not particularly limited as long as the object of the present invention is achieved, but is preferably 15 μm to 5 mm in thickness because of excellent foamability and small problems such as breakage. From the viewpoint of properties, the range of 15 to 100 μm is most preferable.

Since the paper base material which comprises the laminated body of this invention is excellent in heat insulation and economical efficiency, the basic weight of a paper base material is 160-260 g / m < ² >. When the basis weight of the paper is less than 160 g / m ² , the thickness after foaming is inferior, which is not preferable, and when the paper weight exceeds 260 g / m ² , the economic efficiency is inferior, which is not preferable. Since it is excellent in foaming thickness, Preferably it is 180-260 g / m < ² >, More preferably, it is 180-230 g / m < ² >.

The moisture contained in the paper base material constituting the laminate of the present invention is to foam the (A) layer by heating, and is not particularly limited as long as the object of the present invention is achieved. 10-22 g / m ² is preferable because the foamed appearance of the layer (A) is excellent, and more preferably 15-20 g / m ² .

Moreover, since it is excellent in heat insulation, the moisture content of the paper base material after laminating the high-pressure method low density polyethylene (a) and the polyethylene resin (b) is 14 g / m ² or more and less than 22 g / m ² , Since it is excellent in foaming thickness and foaming appearance, 17 g / m < ² > or more and less than 22 g / m < ² > are preferable, More preferably, it is 17-20 g / m < ² >. It is not preferable because the poor thermal insulation is less than 14 g / ^{m 2,} unfavorably poor in foaming appearance at 22 g / ^{m 2} or more.

  As a technique for obtaining the laminate of the present invention, a technique obtained by extrusion laminating high pressure method low density polyethylene (a) and polyethylene resin (b) and heating and foaming, and (A) foam to be a layer to paper An example is a method of bonding and obtaining a polyethylene resin (b) by extrusion lamination. Since processing is easy, a method obtained by tandem laminating a high-pressure low-density polyethylene (a) and a polyethylene resin (b) and heating and foaming is preferable.

  Examples of the method for obtaining a laminate by an extrusion laminate molding method include various extrusion lamination methods such as a single lamination method, a tandem lamination method, a sandwich lamination method, and a coextrusion lamination method. The temperature of the resin in the extrusion laminating method is preferably in the range of 260 to 350 ° C, and the surface temperature of the cooling roll is preferably in the range of 10 to 50 ° C.

In addition, in the extrusion laminating process, when a method in which the base material adhesion surface of the layer is bonded to the base material by exposing the base material adhesion surface of the layer to the oxygen-containing gas or the ozone-containing gas immediately after forming the extruded layer in a molten state, It is preferable because of its excellent adhesiveness with the material layer. When the adhesiveness between the thermoplastic resin and the substrate is improved by the ozone-containing gas, the ozone gas treatment amount is 0.5 mg or more of ozone per 1 m ^{2 of the} film made of the thermoplastic resin extruded from the die. It is preferable to spray.

  The extrusion laminating method in the method of obtaining the laminate of the present invention by heat foaming further improves the adhesion between the thermoplastic resin layer and the base material layer, so that the polyethylene resin does not foam, for example, 30 ° C. Heat treatment can be performed at a temperature of ˜60 ° C. for 10 hours or more. Moreover, you may perform well-known surface treatments, such as a corona treatment, a flame treatment, and a plasma treatment, with respect to the adhesive surface of a paper base material as needed. If necessary, an anchor coating agent may be applied to the paper substrate.

  As a method for obtaining the foam laminate of the present invention, in order to excel in the heat insulation and economy of the foam laminate, water is applied to one or both sides of the paper substrate before laminating the polyethylene resin and the substrate layer. It is preferable.

  The method of applying moisture is not particularly limited as long as the object of the present invention is achieved, and examples thereof include methods using a roll coater, a lip coater, a spray device, a die coater, a gravure device, a dampening device, and the like. be able to. A method using a dampening device is preferable because the amount of water applied is uniform.

  Such a dampening apparatus includes, for example, a product name “High Rotor S” from Suzuki Sangyo Co., Ltd., a product name “WEKO Rotor Dampening” from Nikka Co., Ltd., and a trade name “Toko Electronics Co., Ltd.” "TSD-3000" is sold. In particular, it is preferable to use “High Rotor S” because there is no uneven application of water and the quality is stable.

The amount of water applied in the present invention is not particularly limited as long as the object of the present invention is achieved, but the expansion ratio of the high-pressure method low-density polyethylene (a) can be increased, and the paper base material and the high-pressure method low-density can be used. Since the adhesive strength with polyethylene (a) and / or polyethylene-based resin (b) does not decrease, 0.5 to 20 g / m ² is preferable, more preferably 0.5 to 10 g / m ² or less, and most preferably 1. 0.0 to 6.0 g / m ² .

  As a heating method in the method of obtaining the laminate of the present invention by heat foaming, in addition to hot air, electric heat, and electron beam, the laminate is formed into a container shape, and a high-temperature object is filled to use the heat of the filling. Any means can be used. Heating can be performed by a batch method in an oven, a continuous method using a conveyor, or the like.

  The heating temperature and the heating time vary depending on the substrate to be used and the type of the thermoplastic resin, but the heating temperature is generally 110 ° C. to 200 ° C., and the heating time is 10 seconds to 5 minutes. .

  The thickness after foaming of the layer (A) constituting the laminate of the present invention is preferably 500 μm or more, more preferably 600 μm or more, and most preferably 700 μm or more because of excellent heat insulation.

The ratio of the thickness (μm) after foaming of the (A) layer to the basis weight (g / m ² ) of the paper is in the range of 2.5 to 5.0, because it is excellent in foam appearance and economy. Preferably it is 3.5-5.0, More preferably, it is 3.5-4.5. If the ratio of the thickness of the (A) layer after foaming to the basis weight of the paper is less than 2.5, it is not preferable because it is inferior in economic efficiency, and if it exceeds 5.0, it is not preferable because it is inferior in foam appearance.

  The laminate of the present invention is characterized in that at least (A) layer / paper substrate / (B) layer is laminated, and (A) layer, paper substrate, and (B) layer 3 It may contain not only the component but also other components such as the (C) layer. Specifically, (A) layer / paper substrate / (B) layer, (A) layer / paper substrate / (B) layer / (A) layer, (B) layer / paper substrate / (A) Layer / (B) layer, (A) layer / paper substrate / (B) layer / (B) layer, (A) layer / (A) layer / paper substrate / (B) layer, (A) layer / Paper substrate / (B) layer / (C) layer, (B) layer / paper substrate / (A) layer / (C) layer, (C) layer / (B) layer / paper substrate / (A) Layer / (B) layer / (C) layer, (A) layer / paper substrate / (B) layer / (C) layer / (B) layer / (A) layer, (B) layer / paper substrate / Examples include (A) layer / (C) layer / (A) layer / (B) layer.

  Examples of the layer (C) include layers formed from synthetic polymer, woven fabric, non-woven fabric, metal foil, papers, cellophane and the like. For example, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon 6 and nylon 66, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene- Methacrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyethylene resin such as ionomer, polypropylene resin, polybutene, acrylic resin, polyvinyl alcohol, polymethylpentene, polyvinyl chloride, Examples thereof include a layer formed from a synthetic polymer such as polyvinylidene chloride, polystyrene, polycarbonate, polyurethane, and cellulose resin. Further, these polymer films and sheets may be further subjected to aluminum vapor deposition, alumina vapor deposition, silicon dioxide vapor deposition, or acrylic treatment. Further, these polymer films and sheets may be further printed using urethane ink or the like. Examples of the metal foil include aluminum foil and copper foil, and examples of paper include kraft paper, fine paper, stretched paper, glassine paper, paperboard such as base paper for cups and photographic paper.

  According to the present invention, it is possible to obtain a foamed laminate having a large thickness of the foamed layer, showing good heat insulating properties and foamed appearance, and being excellent in economic efficiency.

Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.
(1) Density Density was measured based on JIS K6922-1 (2010).
(2) Melt mass flow rate (MFR)
MFR was measured according to JIS K6922-1 (2010).
(3) Heating foaming In a gear aging tester (No. 102-SHF-77, manufactured by Yasuda Seiki Seisakusho), a sample obtained by cutting the laminate obtained in the example into 10 cm × 20 cm and forming it into a cylindrical shape was heated to 120 ° C. And then left to stand for a predetermined time, and then taken out and cooled in air to room temperature.
(4) Moisture content of paper substrate The paper substrate before and after the lamination of the polyethylene resin was measured using a Karl Fischer method moisture measurement device (trade name CA-05, manufactured by Mitsubishi Chemical Corporation). The measurement temperature is 165 ° C.
(5) Foam Layer Thickness Samples were taken of the foam obtained in the examples and the laminate laminate before foaming as a blank, and a cross-sectional photograph was taken with an optical microscope. The thickness of the foam layer was measured from the cross-sectional photograph and measured at five locations. When the thickness of the foamed layer was less than 500 μm, it was rated as ×, when it was 500 μm or more and less than 600 μm, Δ when it was 600 μm or more and less than 700 μm, and ○ when 700 μm or more. In addition, it evaluated that it was favorable if the foamed layer thickness was 500 micrometers or more.
(6) State of foam surface The smoothness of the surface of the obtained foam was visually observed. The case where the smoothness of the surface was good was marked with ◯, the case where it was good but slightly inferior was marked with Δ, and the case where it was poor was marked with ×.
(7) with respect to the basis weight of the paper layer (A) thickness of the foam layer was measured from the cross section photograph taken by the thickness optical microscope (A) layer thickness (hereinafter abbreviated as D _A), basis weight of the paper ( The ratio (D _A / B) of the thickness of (A) layer to (hereinafter abbreviated as B) was obtained. If D _A / B is 2.5 or more, the economy is good.

Example 1
As the high pressure method low density polyethylene (a), a high pressure method low density polyethylene (trade name Petrocene 212, manufactured by Tosoh Corporation) having an MFR of 13 g / 10 min and a density of 919 kg / m ³ is used as a polyethylene resin ( As b), high-density polyethylene (trade name Petrocene LW04-1 manufactured by Tosoh Corporation) (B1) having an MFR of 7 g / 10 min and a density of 940 kg / m ³ was used.

First, a paper having a moisture content of 15.5 g / m ² and a basis weight of 220 g / m ² using a high rotor S (manufactured by Suzuki Sangyo Co., Ltd.) on the surface of the paper substrate on which (A1) is laminated. After applying ² g / m ² of water to the substrate, (A1) is supplied to a single-screw extrusion laminator (manufactured by Musashinokikai Co., Ltd.) having a screw with a diameter of 90 mmφ, and extruded from a T-die at a temperature of 320 ° C. Extrusion lamination was performed on the substrate so that the take-up speed was 60 m / min, the air gap length was 130 mm, and the thickness was 40 μm. Further, (B1) was supplied to a single screw extruder (Musashi Nokikai Co., Ltd.) having a screw with a diameter of 90 mmφ, a temperature of 320 ° C., a take-up speed of 60 m / min, an air gap length of 130 mm, and 20 μm Extrusion laminating was performed to obtain a thickness, and a laminate obtained by laminating a high-pressure low-density polyethylene (A1), a paper base material having a water content of 16.5 g / m ² , and a high-density polyethylene (B1) in this order was obtained. . The obtained laminate was heated and foamed at 120 ° C. for 5 minutes to obtain a foam laminate. About the obtained laminated body before and behind foaming, the thickness of the foamed layer and the state of the foamed surface were evaluated. The evaluation results are shown in Table 1. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 2
A laminate before and after foaming by the same method as in Example 1 except that the polyethylene-based resin used in Example 1 was used and 3 g / m ² of water was applied to the surface of the paper substrate on which (A1) was laminated. Got. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 1. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 3
A laminated body before and after foaming by the same method as in Example 1 except that the polyethylene-based resin used in Example 1 was used and 6 g / m ² of water was applied to the surface of the paper substrate on which (A1) was laminated. Got. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 1. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 4
A laminated body before and after foaming was obtained in the same manner as in Example 3 except that the polyethylene resin used in Example 3 was used and (A1) was laminated so that the thickness before foaming was 50 μm. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 5
A laminated body before and after foaming was obtained in the same manner as in Example 3 except that the polyethylene resin used in Example 3 was used and (A1) was laminated so that the thickness before foaming was 60 μm. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 6
(B) As a resin for the layer, 90% by weight of high density polyethylene (trade name Nipolon Hard 2000 manufactured by Tosoh Corporation) having an MFR of 21 g / 10 min and a density of 952 kg / m ³ , and MFR of 1.6 g / 10 min The high-pressure low-density polyethylene having a density of 919 kg / m ³ (trade name Petrocene 360 manufactured by Tosoh Corporation) was blended to 10% by weight, and a single-screw extruder (Placo Corporation diameter 50 mm) was used. Laminate molding was carried out in the same manner as in Example 5 except that the melt-kneaded ethylene resin composition (B2, MFR 16 g / 10 min, density 949 kg / m ³ ) was used to obtain a laminate before and after foaming. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 1. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 7
(B) As the resin of the layer, 90% by weight of high density polyethylene (trade name Nipolon Hard 1000 manufactured by Tosoh Corporation) having an MFR of 20 g / 10 min and a density of 966 kg / m ³ , and MFR of 1.6 g / 10 min The high-pressure low-density polyethylene having a density of 919 kg / m ³ (trade name Petrocene 360 manufactured by Tosoh Corporation) was blended to 10% by weight, and a single-screw extruder (Placo Corporation diameter 50 mm) was used. Laminate molding was performed in the same manner as in Example 5 except that the melt-kneaded ethylene resin composition (B3, MFR 16 g / 10 min, density 961 kg / m ³ ) was used, and a laminate before and after foaming was obtained. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 1. The thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the adhesive strength with the paper substrate were all good.

Example 8
A laminated body before and after foaming by the same method as in Example 7 except that the polyethylene resin used in Example 7 was used and 10 g / m ² of water was applied to the surface of the paper substrate on which (A1) was laminated. Got. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 1. Both the thickness of the foamed layer after foaming, the smoothness of the foamed layer, and the economy were good.

Example 9
A laminate before and after foaming was obtained by the same method as in Example 4 except that a paper base having a water content of 13.5 g / m ² and a basis weight of 180 g / m ² was used as the paper base. . About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The thickness of the foamed layer after foaming, the foam appearance, and the economy were all good.

Example 10
A laminate before and after foaming was obtained in the same manner as in Example 4 except that a paper substrate having a water content of 17.5 g / m ² and a basis weight of 250 g / m ² was used as the paper substrate. . About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The thickness of the foamed layer after foaming, the foam appearance, and the economy were all good.

比較例１
実施例１に使用したポリエチレン系樹脂を使用し、紙基材に水を塗布しなかったこと以外は、実施例１と同様の手法により発泡前後の積層体を得た。得られた積層体について、発泡層の厚み、発泡表面の状態を評価した。結果を表２に示す。発泡層の平滑性は良好であったものの、発泡後の発泡層の厚み、経済性に劣っていた。

Comparative Example 1
A laminate before and after foaming was obtained in the same manner as in Example 1 except that the polyethylene-based resin used in Example 1 was used and water was not applied to the paper substrate. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the smoothness of the foam layer was good, the thickness of the foam layer after foaming was inferior to the economy.

Comparative Example 2
A laminate before and after foaming was obtained in the same manner as in Example 4 except that the polyethylene-based resin used in Example 4 was used and water was not applied to the paper substrate. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the thickness of the foamed layer after foaming and the smoothness of the foamed layer were good, they were inferior in economic efficiency.

Comparative Example 3
A laminate before and after foaming was obtained in the same manner as in Example 5 except that the polyethylene-based resin used in Example 5 was used and water was not applied to the paper substrate. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the thickness of the foamed layer after foaming and the smoothness of the foamed layer were good, they were inferior in economic efficiency.

Comparative Example 4
A laminate before and after foaming by the same method as in Example 5 except that the polyethylene-based resin used in Example 5 was used and 12 g / m ² of water was applied to the surface of the paper substrate on which (A1) was laminated. Got. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the thickness and economy of the foamed layer after foaming were good, the smoothness of the foamed layer was poor.

Comparative Example 5
A laminated body before and after foaming was obtained in the same manner as in Example 9 except that the polyethylene resin used in Example 9 was used and water was not applied to the paper substrate. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the smoothness of the foam layer was good, the thickness of the foam layer after foaming was inferior to the economy.

Comparative Example 6
A laminate before and after foaming was obtained in the same manner as in Example 10 except that the polyethylene-based resin used in Example 10 was used and water was not applied to the paper substrate. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. The results are shown in Table 2. Although the foam layer thickness after foaming and the smoothness of the foam layer were good, they were inferior in economic efficiency.

Comparative Example 7
A laminated body before and after foaming was obtained by the same method as in Example 8 except that the polyethylene resin used in Example 8 was used and (A1) was laminated so that the thickness before foaming was 80 μm. About the obtained laminated body, the thickness of the foam layer and the state of the foam surface were evaluated. Although the thickness and economy of the foamed layer after foaming were good, the smoothness of the foamed layer was poor.

  The foamed laminate of the present invention is suitably used for containers that require heat insulation, such as paper containers for high-temperature beverages such as coffee and soup, and containers for instant foods such as instant noodles.

Claims (8)

A foam laminate comprising at least (A) layer / paper base material layer / (B) layer, wherein (A) layer is a foam layer, wherein (A) layer is measured according to JIS K6922-1 (2010) been density 910 kg / ^{m 3} or more 930 kg / ^{m 3} or less is high-pressure low-density polyethylene (a), (B) layer is JIS K6922-1 (2010 years) density measured by the 935 kg / ^{m 3} or more 970kg A foamed laminate comprising: a polyethylene-based resin (b) having a / m ³ or less and satisfying the following (i) to (iii):
(I) The ratio of the thickness (μm) of the foamed (A) layer to the basis weight (g / m ² ) of the paper substrate is 2.5 or more and 5.0 or less.
(Ii) The basis weight (g / m ² ) of the paper substrate is 160 or more and 260 or less.
(Iii) The water content of the paper base material after laminating the high-pressure method low-density polyethylene (a) and the polyethylene-based resin (b) is 14 g / m ² or more and less than 22 g / m ² . The water content of the paper base material after laminating the high-pressure method low density polyethylene (a) and the polyethylene resin (b) is 17 g / m ² or more and less than 22 g / m ² . Foam laminate. The ratio of the thickness (μm) of the foamed (A) layer to the basis weight (g / m ² ) of the paper substrate is 3.5 or more and 5.0 or less. The foamed laminate described in 1. The foamed laminate according to claim 1, wherein the thickness (μm) of the (A) layer before foaming is 30 or more and 70 or less. Polyethylene resin (b) is, according to claim 1, density measured by JIS K 6922-1 (2010 years) is equal to or less than 945 kg / ^{m 3} or more 970 kg / ^{m 3} Foam laminate method. Polyethylene resin (b) The foam laminate according to claim 5, density measured by JIS K 6922-1 (2010 years) is characterized in that it is 950 kg / ^{m 3} or more 965 kg / ^{m 3} or less. The polyethylene resin (b) is an ethylene resin composition (e) comprising 10 to 90% by weight of high density polyethylene (c) and 10 to 90% by weight of high pressure method low density polyethylene (d). The foamed laminate according to any one of claims 1 to 6. The container which consists of a foaming laminated body of Claims 1-7.