JP2018069683A - Laminate for foaming and foamed laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate for foaming which has high productivity and exhibits excellent heat insulation properties and foam appearance.SOLUTION: A laminate for foaming contains at least layer (A)/paper base material layer/layer (B), where the layer (A) is composed of low density polyethylene (a) satisfying (i) to (iii), and the layer (B) is composed of a polyethylene-based resin (b) having a density measured according to JIS K6922-1 (1997) of 930 kg/mor more and 970 kg/mor less. (i) melt mass flow rate (MFR) measured according to JIS K6922-1 (1997) of 5 g/10 min or more and 50 g/10 min or less. (ii) density measured according to JIS K6922-1 (1997) of 910 kg/mor more and 930 kg/mor less. (iii) static contact angle with water in non-adhesion surface of paper base material of 104° or more and 115° or less.SELECTED DRAWING: None

Description

  The present invention relates to a foamed laminate and a foamed laminate having high productivity and good heat insulation and foam appearance.

  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.

  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 the low melting point heat is applied to the outer wall surface of the base material of the container body member. There has been proposed a heat-insulating paper container in which a plastic synthetic resin film is laminated and the low-melting thermoplastic synthetic resin film is foamed by heat treatment (see, for example, Patent Document 4).

  However, heat insulating paper containers with high melting point thermoplastic synthetic resin on the inner wall surface have good heat insulation, but if the processing speed when laminating low melting point thermoplastic resin is increased, the foam appearance deteriorates and production It was inferior.

Japanese Patent Publication No. 48-32283 JP-A-57-110439 JP 2001-270571 A JP 2004-58534 A

  An object of the present invention is to provide a foamed laminate and a foamed laminate that have high productivity and exhibit good heat insulation and foam appearance.

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific foam laminate and foam laminate are highly productive and exhibit excellent heat insulation and foam appearance. The invention has been completed.

That is, the low-density polyethylene (a) including at least (A) layer / paper base material layer / (B) layer, wherein the (A) layer satisfies (i) to (iii), and the (B) layer is JIS K692-1. it relates foaming laminate wherein the density measured by the (1997) is composed of 930 kg / ^{m 3} or more 970 kg / ^{m 3} or less is polyethylene resin (b).

(I) The melt mass flow rate (MFR) measured by JIS K6922-1 (1997) is 5 g / 10 min or more and 50 g / 10 min or less. (Ii) The density measured by JIS K6922-1 (1997) is 910 kg / m. ³ or more and 930 kg / m ³ or less (iii) The static contact angle with water on the non-adhesive surface of the paper substrate is 104 ° or more and 115 ° or less. The layer (A) of the foaming laminate is foamed. It is related with the foaming laminated body characterized by these.

  Hereinafter, the present invention will be described in detail.

  The low density polyethylene (a) constituting the laminate for foaming of the present invention is composed of a high pressure method low density polyethylene (c), a linear low density polyethylene (d) or a composition thereof.

  The high pressure method low density polyethylene (c) can be obtained by a conventionally known high pressure method radical polymerization method.

  Linear low density polyethylene (d) can be obtained by copolymerizing ethylene and α-olefin by high, medium and low pressure ion polymerization using Ziegler-Natta catalyst, Phillips catalyst, metallocene catalyst, It may have a long chain branched structure. Since it is excellent in production efficiency and foam appearance, an ethylene / α-olefin copolymer having no long chain branched structure is preferable.

  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.

The density (hereinafter simply abbreviated as density) measured by JIS K6922-1 (1997) of low density polyethylene (a) is excellent in heat insulation and foam appearance, and is in the range of 910 to 930 kg / m ³ . more preferably 914~925kg / ^{m 3,} still more preferably from 916~920kg / ^{m 3.} If the density of the low density polyethylene (a) is less than 910 kg / m ^3, it is not preferable because it is inferior in foam appearance, and if it exceeds 930 kg / m ³ , it is not preferable because it is inferior in heat insulation.

  Also, the melt mass flow rate (hereinafter simply abbreviated as MFR) measured by JIS K6922-1 (1997) of low density polyethylene (a) is in the range of 5 to 50 g / 10 min. Since it is excellent, the range of 12-30 g / 10min is preferable, More preferably, it is 12-18 g / 10min, Most preferably, it is the range of 12-16g / 10min. When the MFR of the low density polyethylene (a) is less than 5 g / 10 minutes, the foamed appearance is inferior, which is not preferable, and when it exceeds 30 g / 10 minutes, the laminate processability is inferior.

  The swell ratio (hereinafter simply abbreviated as SR) measured at 235 ° C. of the low density polyethylene (a) constituting the present invention is preferably in the range of 1.40 to 1.80, more preferably, because of excellent foaming performance. The range is 1.40 to 1.65, most preferably 1.45 to 1.60.

This SR uses the melt indexer used in JIS K6922-1 (1997), extrudes the resin filled in the device under the conditions of a temperature of 235 ° C. and an extrusion rate of 3 g / min, and installs directly under the orifice. The strand-shaped extrudate is collected with a graduated cylinder containing isopropanol and the diameter (D) of the strand is divided by the orifice diameter (D ₀ ) of the melt indexer.

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

  When the polyolefin is mixed with the low density polyethylene (a) constituting the laminate of the present invention, a pellet mixture in which the pellets of the low density polyethylene (a) and the polyolefin pellets are mixed in a solid state may be used. 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 kneader, the melting temperature is preferably about the melting point of the polyolefin resin to about 300 ° C.

  In addition, the low density polyethylene (a) constituting the laminate of the present invention is generally used for polyolefin resins such as antioxidants, light stabilizers, antistatic agents, lubricants, antiblocking agents, and the like as necessary. The additives may be added within a range not impairing the object of the present invention.

Because of excellent foam appearance, low density polyethylene (a) has a density of 910 kg / ^{m 3} or more 930 kg / ^{m 3} or less is high-pressure low-density polyethylene (c) is 30 parts by weight or more 90 parts by weight or less, density of 850kg / M ³ or more and 940 kg / m ³ or less linear low density polyethylene (d) containing 10 parts by weight or more and 70 parts by weight or less (total of (c) and (d) is 100 parts by weight) It is preferable that it is a thing (e).

The MFR (hereinafter referred to as MFR _c ) of the high-pressure method low-density polyethylene (c) contained in the polyethylene resin composition (e) is preferably in the range of 8 to 50 g / 10 minutes because of excellent productivity and foam appearance. More preferably, it is 10-30 g / 10min, Most preferably, it is 10-20g / 10min.

  The SR of such a high pressure method low density polyethylene (c) is preferably in the range of 1.40 to 1.80, more preferably 1.40 to 1.65, and most preferably because of excellent productivity and foaming performance. Is in the range of 1.45 to 1.60.

The density of the high-pressure low-density polyethylene (c) is excellent in heat insulating property and foaming appearance, more preferably in the range of 914~924kg / ^{m 3,} still more preferably from 916~920kg / ^{m 3.}

In addition, the MFR (hereinafter referred to as MFR _d ) of the ethylene / α-olefin copolymer (d) contained in the polyethylene resin composition (e) is excellent in productivity and foam appearance, and therefore 1-30 g / 10 min. The range is preferably 3 to 25 g / 10 min, and most preferably 6 to 20 g / 10 min.

The density of such a linear low-density polyethylene (d) are for excellent heat insulation and foam appearance, more preferably in the range of 880~930kg / ^{m 3,} more preferably in the range of 890~920kg / ^{m 3} .

Moreover, since the melt tension (hereinafter abbreviated as MS ₁₉₀ ) measured at a temperature of 190 ° C. and a take-off speed of 10 m / min of the linear low density polyethylene (d) is excellent in foam appearance, a range of 2 to 20 mN is preferable. More preferably, it is the range of 2-10 mN.

This MS ₁₉₀ (mN) is a set temperature under the condition that a capillary viscometer with a barrel diameter of 9.55 mm is equipped with a die having a length of 8 mm, a diameter of 2.095 mm, an inflow angle of 90 °, and a heat retaining chamber. It is a value measured at 190 ° C., an extrusion speed of 10 m / min, and a take-up speed of 10 m / min.

Among these, because of excellent productivity and foam appearance, the ratio _MFR c / MFR _d of MFR _d of MFR _c and linear low density polyethylene high-pressure low-density polyethylene (c) (d) 0.8 The polyethylene resin composition (e) satisfying ˜15.0 is preferred, and since the foam appearance is excellent, MFR _c / MFR _d is more preferably in the range of 0.8 to 6.0, most preferably The range is 1.0 to 4.0.

The density of the polyethylene resin (b) constituting the foamed laminate of the present invention is excellent in heat insulation and foaming stability, and is therefore in the range of 930 to 970 kg / m ³ , more preferably 935 to 970 kg / m ³ , most preferably 945 to 965 kg / m ³ . If the density of the polyethylene resin (b) is less than 930 kg / m ^3, it is not preferable because the heat insulating property is poor, and if 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, You may have a branch. 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 medium / low pressure ethylene homopolymer and high pressure low density polyethylene. The medium / low pressure ethylene homopolymer can be obtained by a conventionally known medium / low pressure ion polymerization method. Moreover, 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.

  The method for obtaining the 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. Such a copolymer can be conveniently selected from commercially available products.

Among these, since it is excellent in laminate moldability, the density is 930 to 980 kg / m ³ , and it is a medium or high medium composed of at least one of ethylene / α-olefin copolymer and medium / low pressure ethylene homopolymer. An ethylene-based resin composition comprising 90 to 10 parts by weight of a high-pressure low-density polyethylene (g) having a density polyethylene (f) of 10 to 90 parts by weight, an MFR of 1 to 20 g / 10 minutes, and an SR of 1.50 to 2.20 It is preferable that the product (h) (the sum of (f) and (g) is 100 parts by weight) is included.

  Medium / high-density polyethylene is an ethylene homopolymer obtained by a conventionally known medium / low pressure ion polymerization method, ethylene obtained by a high / medium / low pressure ion polymerization method using a Ziegler-Natta catalyst, a Philips catalyst, or a metallocene catalyst. -An alpha olefin copolymer is illustrated.

  In addition, in the medium / high-density polyethylene (f), 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, since the ethylene-based resin composition (h) is excellent in laminate processability. The range of minutes.

Furthermore, the density of the medium / high-density polyethylene (f) is more preferably 945 to 975 kg / m ³ , because the ethylene resin composition (h) has excellent laminate processability and productivity.

  The MFR of the high-pressure method low-density polyethylene (g) is more preferably in the range of 0.3 to 10 g / 10 min, and most preferably 1 to 4 g / min because of excellent extrusion lamination processability of the ethylene-based resin composition (h). The range is 10 minutes.

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

  Furthermore, the SR of the high-pressure method low-density polyethylene (g) is more preferably in the range of 1.75 to 2.20, most preferably 1.75, since the SR of the ethylene-based resin composition (h) is excellent in film formation stability. It is in the range of 90 to 2.20.

  The MFR of the ethylene-based resin composition (h) is preferably in the range of 1 to 50 g / 10 minutes, and more preferably in the range of 3 to 20 g / 10 minutes because of excellent laminate moldability.

  The polyethylene resin (h) 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 foamed laminate of the present invention, a pellet mixture in which the pellets of the polyethylene resin (b) and the polyolefin pellets are mixed in a solid state may be used. A mixture obtained by melt-kneading with a single 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 foaming laminate of the present invention is not particularly limited as long as the object of the present invention is achieved, but is excellent in foaming appearance, and therefore has a range of 60 to 150 μm. More preferably, it is 80-120 micrometers, More preferably, it is 80-100 micrometers.

  Further, the thickness of the layer (B) is not particularly limited as long as the object of the present invention is achieved, but it is preferably 20 to 100 μm because of excellent foamability and small problems such as breakage. From the viewpoint of economy, the range of 20 to 50 μm is most preferable.

  The thickness of the layer (A) constituting the foamed laminate of the present invention is preferably 800 μm or more, more preferably 900 μm or more, and most preferably 1000 μm or more because of excellent heat insulation.

Although there is no limitation in particular about the paper base material which comprises the laminated body for foaming of this invention, since the expansion ratio of a low density polyethylene (a) can be improved, the basic weight of a paper base material is 150-400 g / m. ² is more preferable, and 250 to 350 g / m ² is more preferable.

Although there is no restriction | limiting in particular about the water | moisture content contained in such a paper base material, it is preferable that it is 15-30 g / m < ² > from the foaming magnification of low density polyethylene (a) improving, More preferably, 20-20. 30 g / ^{m 2,} and most preferably 20~26g / ^{m 2.}

  As a method for obtaining the foamed laminate of the present invention, a method of extrusion laminating low-density polyethylene (a) and polyethylene-based resin (b) is exemplified, but low-density polyethylene (a) is easy to process. And a technique of tandem laminating polyethylene resin (b) is preferred.

  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 240 to 350 ° C, and the surface temperature of the cooling roll is preferably in the range of 10 to 50 ° C.

  In particular, the resin temperature directly under the T-die when extrusion laminating the low density polyethylene (a) has a large static contact angle with water of the low density polyethylene (a) and is excellent in foam appearance. Is preferable, more preferably 250 to 300 ° C, and most preferably 260 to 290 ° C.

  Further, in the extrusion laminate molding method, the processing speed when forming the (A) layer made of low-density polyethylene (a) is preferably in the range of 50 to 200 m / min because of excellent foam appearance and productivity. Preferably it is 70-150 m / min, Most preferably, it is 80-130 m / min.

In such an extrusion laminating process, immediately after the polyethylene-based resin is made into an extruded layer in a molten state, the base material adhesion surface of the layer is exposed to an oxygen-containing gas or an ozone-containing gas, and a method of bonding to the base material is used. It is preferable because of excellent adhesiveness with the base 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.

In particular, since it has excellent foam appearance, it is preferable to perform ozone treatment when extrusion laminating low density polyethylene (a), and ozone gas per 1 m ^{2 of} molten film made of low density polyethylene (a) extruded from a die. Is preferably sprayed with 0.5 to 100 mg of ozone, more preferably 3 to 50 mg, and most preferably 5 to 40 mg.

  The extrusion laminating method in the method of obtaining the laminate of the present invention further improves the adhesiveness between the thermoplastic resin layer and the base material layer, so that the polyethylene resin does not foam, for example, 3 to 60 ° C. Heat treatment can be performed at a temperature 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.

  The static contact angle (°) with water on the non-adhesive surface of the paper substrate of the low density polyethylene (a) constituting the foam laminate of the present invention is 104 to 115 ° because of excellent foam appearance. More preferably, it is the range of 105-115 degrees, Most preferably, it is the range of 107-115 degrees. When the static contact angle with water is less than 104 ° or more than 115 °, the foaming performance is inferior.

  The static contact angle (°) with water is measured by the droplet method. In an environment of a temperature of 23 ° C. and a relative humidity of 50%, pure water or ultrapure water having an electric conductivity of 1 μS / cm or less is used as a measurement solvent, and 1.0 μL of the measurement solvent is dropped on the surface of the low density polyethylene (a). 2 seconds later, an image of a droplet is obtained and analyzed by the 2 / θ method. In addition, surface treatment such as corona treatment and frame treatment for the purpose of improving printability, surface decoration such as printing, transfer, metal vapor deposition, and improvement of surface roughness for the purpose of improving cosmetics, etc. is reduced. When performing to a density polyethylene (a), a static contact angle is measured in the state before processing.

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

  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 low density polyethylene (a) can be increased, and the paper base material and the low density polyethylene (a) and / or because the adhesive strength between the polyethylene resin (b) is not lowered, preferably in the range of 1.5~30g / ^{m 2,} the range of 3 to 15 g / ^{m 2} is more preferable.

  By heating the foaming laminate of the present invention, a foaming laminate in which the layer (A) is foamed can be obtained.

  As a heating method in the method of obtaining the foamed laminate of the present invention by heat foaming, in addition to hot air, electric heat, electron beam, the laminate is formed into a container shape, and the heat of the filling is used by filling a hot object. 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 heat source for heating is not particularly limited as long as this object is achieved, and examples of the laminated body and molded container include hot air, electric heat, and electron beam, and the container formed with the laminated body contains a high-temperature object. For example, the heat of the filling can be used. Further, the heating method can be performed by a batch method in an oven, a continuous method using a conveyor, or the like.

Conditions such as the heating temperature and the heating time are not particularly limited as long as the object of the present invention is achieved. In general, when hot air is used as a heat source, the heating temperature is not less than the melting point of the low density polyethylene (a) to 150. C. or less, the air volume is 0.5 to 2.0 m ³ / hour, and the heating time is 10 seconds to 6 minutes.

  The foaming laminate of the present invention comprises at least (A) layer / paper substrate / (B) layer, and is composed of three components: (A) layer, paper substrate, and (B) layer. It may contain not only what consists of only other components, for example, (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. In addition, the symbol / between layers represents that it is an adjacent 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.

  The foam laminate of the present invention is used as a heat insulating paper container used for at least a trunk member.

  The foamed laminate of the present invention is highly productive and becomes a foamed laminate that exhibits good thermal insulation and foam appearance when foamed.

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 according to JIS K6922-1 (1997).
(2) Melt mass flow rate (MFR)
MFR was measured according to JIS K6922-1 (1997).
(3) Swell ratio (SR)
Using the melt indexer used in JIS K6922-1 (1997), the resin filled in the apparatus was extruded from the orifice under the conditions of a temperature of 235 ° C. and an extrusion rate of 3 g / min, and isopropanol placed immediately below the orifice was placed. The strand-shaped extrudate was collected with a graduated cylinder, and the strand diameter (D) was divided by the orifice diameter (D ₀ ) of the melt indexer.
(4) Heating foaming A gear aging tester (No. 102-SHF-77 manufactured by Yasuda Seiki Seisakusakusho Co., Ltd.) in which 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 a predetermined temperature. The mixture was allowed to stand for a predetermined time while applying hot air therein, and then taken out and cooled to room temperature in air.
(5) Water content of paper base material The paper base material before lamination of the polyethylene resin was measured using a Karl Fischer method water measuring device (trade name CA-05, manufactured by Mitsubishi Chemical Corporation). The measurement temperature is 165 ° C.
(6) Static contact angle with water The laminate for foaming obtained according to the example is cut out to 5 cm × 10 cm, the surface of the layer (B) is pasted on an acrylic plate, and the paper substrate of the layer (A) is non-coated. Sample with adhesive surface as surface, measuring device is DM-300 manufactured by Kyowa Interface Science, measurement software is FAMAS, measurement environment is temperature 23 ° C, relative humidity 50%, measurement solvent has electrical conductivity of 1 μS / cm or less The ultrapure water and the measurement solvent amount to be dropped are 1.0 μL, and an image of a droplet after 2 seconds after the ultrapure water is dropped on the surface of the low density polyethylene (a) is obtained. The static contact angle with water analyzed by the above. The average value of the values measured at 10 locations was used.
(7) Melt tension at 190 ° C. (MS ₁₉₀ )
A capillary viscometer with a barrel diameter of 9.55 mm equipped with a die and a heat retaining chamber having a length of 8 mm, a diameter of 2.095 mm, an inflow angle of 90 °, and a temperature set at 190 ° C. in a thermostatic chamber set at 23 ° C. (Toyo Seiki Seisakusho, trade name: Capillograph) is filled with 18 g of polyethylene resin, the piston lowering speed is set to 10 mm / min, the take-up speed is set to 10 m / min, and the load (mN) required for take-up is melt tension (MS ₁₉₀ ).
(8) Foam Layer Thickness Samples were taken of the foam obtained in 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.
(9) 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 rated as ◎, the case where it was slightly good as ○, the case where it was good but slightly inferior as Δ, and the case where it was poor as x. "
Example 1
As the resin of the (A) layer, a high-pressure low-density polyethylene (A1) manufactured by Tosoh Corporation having an MFR of 14 g / 10 min, a density of 917 kg / m ³ , and an SR of 1.74 is used. As the resin, 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, (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 the T die so that the resin temperature immediately below the T die is 305 ° C. 6 / ^{m 2,} a basis weight of 320 g / ^m speed take-off on a ² at a paper substrate is 80 m / min, was extrusion lamination molding to air gap length a thickness of 70μm at 130 mm. Further, (B1) was supplied to a single screw extruder (made by Musashinokikai Co., Ltd.) having a screw having a diameter of 90 mmφ, and a temperature of 320 ° C., a take-up speed of 80 m / min, and an air gap length of 130 mm, (B1) Was extruded so as to have a thickness of 40 μm, and a foamed laminate obtained by laminating a high-pressure method low-density polyethylene (A1), a paper base material, 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 foaming laminated body, the thickness of the foaming layer and the state of the foaming surface were evaluated. The evaluation results are shown in Table 1.

Example 2
(A) A foam laminate was obtained in the same manner as in Example 1 except that the resin temperature immediately below the T die of the low density polyethylene (A1) when forming the layer was 280 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 3
(A) A foam laminate was obtained in the same manner as in Example 1 except that the resin temperature immediately below the T die of the low density polyethylene (A1) when forming the layer was 255 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 4
(A) When the layer is formed, the resin temperature immediately below the T die of the low density polyethylene (A1) is 255 ° C., and immediately after forming the extruded layer, 8 mg of ozone gas per 1 m ² of film on the base material adhesion surface of the layer A foam laminate was obtained in the same manner as in Example 1 except that the layered product was exposed. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 5
(A) Implementation was performed except that high-pressure low-density polyethylene (A2) manufactured by Tosoh Corp. with a MFR of 14 g / 10 min, a density of 917 kg / m ³ , and an SR of 1.82 was used as the layer resin. A foam laminate was obtained in the same manner as in Example 3. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 6
(A) Implementation was performed except that high-pressure low-density polyethylene (A3) manufactured by Tosoh Corporation having an MFR of 14 g / 10 min, a density of 917 kg / m ³ , and an SR of 1.64 was used as the resin for the layer (A). A foam laminate was obtained in the same manner as in Example 3. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 7
(A) Implemented except that high-pressure low-density polyethylene (A4 manufactured by Tosoh Corp., A4) having an MFR of 24 g / 10 min, a density of 918 kg / m ³ , and an SR of 1.45 was used as the layer resin. A foam laminate was obtained in the same manner as in Example 3. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 8
As the resin for the layer (A), high-pressure low-density polyethylene (A2) 90 parts by weight, MFR 12 g / 10 min, density 905 kg / m ³ , MS ₁₉₀ 2 mN, ethylene 1 -A hexene copolymer (trade name Nipolon-Z HM510R, C1 manufactured by Tosoh Corporation) blended to 10 parts by weight, and melt-kneaded with a single screw extruder (Placo Corporation diameter 50 mm) A foam laminate was obtained in the same manner as in Example 3 except that the resin composition (A5, MFR 14 g / 10 min, density 916 kg / m ³ , SR 1.49) was used. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Example 9
(A) A foam laminate was obtained in the same manner as in Example 8 except that the take-up speed of the low density polyethylene (A5) when forming the layer was 100 m / min. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 1.

Comparative Example 1
A foam laminate was obtained in the same manner as in Example 1 except that the resin temperature immediately below the T die of the low density polyethylene (A1) when forming the layer (A) was 315 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 2
(A) A foam laminate was obtained in the same manner as in Example 5 except that the resin temperature immediately below the T die of the low density polyethylene (A2) when forming the layer was 315 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 3
A foam laminate was obtained in the same manner as in Example 6 except that the resin temperature immediately below the T die of the low density polyethylene (A3) when forming the layer (A) was 315 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 4
(A) A foam laminate was obtained in the same manner as in Example 7, except that the resin temperature immediately below the T die of the low density polyethylene (A4) when forming the layer was 315 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 5
A foam laminate was obtained in the same manner as in Example 8 except that the resin temperature immediately below the T die of the low density polyethylene (A5) when forming the layer (A) was 315 ° C. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 6
(A) Implementation was performed except that high-pressure low-density polyethylene (A6 manufactured by Tosoh Corp., A6) having an MFR of 3 g / 10 min, a density of 924 kg / m ³ , and an SR of 1.86 was used as the resin for the layer (A). A laminate before foaming was obtained in the same manner as in Example 1. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 7
(A) Implementation was performed except that high-pressure low-density polyethylene (A7 manufactured by Tosoh Corporation) having an MFR of 58 g / 10 min, a density of 917 kg / m ³ , and an SR of 1.26 was used as the resin for the layer (A). A laminate before foaming was obtained in the same manner as in Example 1. The evaluation results are shown in Table 2. When the (A) layer was formed, the laminate thickness was not stable, and the foamed laminate could not be evaluated.

Comparative Example 8
(A) A foam laminate is obtained in the same manner as in Example 1 except that the resin temperature immediately below the T die of the low density polyethylene (A1) when forming the layer is 310 ° C. and the take-up speed is 50 m / min. It was. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

Comparative Example 9
(A) Except that the molding machine for forming the layer was a single screw extrusion laminator (made by Plako Co., Ltd.) having a screw with a diameter of 25 mmφ, the resin temperature just below the T die was 300 ° C., and the take-up speed was 10 m / min. A foamed laminate was obtained in the same manner as in Example 1. About the obtained foaming laminated body, the foaming layer thickness and foaming external appearance were evaluated. The evaluation results are shown in Table 2. The foam appearance was inferior.

  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)

Low density polyethylene (a) that includes at least (A) layer / paper base material layer / (B) layer, and (A) layer satisfies the following (i) to (iii), and (B) layer is JIS K6922-1 ( foam laminate body density measured is characterized in that it is composed of 930 kg / ^{m 3} or more 970 kg / ^{m 3} or less is polyethylene resin (b) by 1997).
(I) The melt mass flow rate (MFR) measured by JIS K6922-1 (1997) is 5 g / 10 min or more and 50 g / 10 min or less. (Ii) The density measured by JIS K6922-1 (1997) is 910 kg / m. ^{3 to} 930 kg / m ³ or less (iii) The static contact angle with water on the non-adhesive surface of the paper substrate is 104 ° to 115 ° The foamed laminate according to claim 1, wherein SR of the low-density polyethylene (a) is 1.40 or more and 1.80 or less. Low-density polyethylene (a) is, JIS K6922-1 (1997 years) measured density is 910 kg / ^{m 3} or more 930 kg / ^{m 3} 90 parts by weight or less is high-pressure low-density polyethylene (c) 30 parts by weight or more or less by And a linear low density polyethylene (d) having a density measured by JIS K6922-1 (1997) of 850 kg / m ³ or more and 940 kg / m ³ or less (10) to 70 parts by weight ((c)) The foamed laminate according to claim 1, wherein the foamed laminate is a polyethylene resin composition (e) containing 100 parts by weight of (d). The foaming laminated body in which the (A) layer of the laminated body for foaming in any one of Claims 1-3 is foaming. A heat insulating paper container, wherein at least the body member is the foamed laminate according to claim 4. A method for producing a laminate in which low-density polyethylene (a) is extrusion laminated to a paper substrate, and the processing speed when extrusion laminating the (A) layer made of low-density polyethylene (a) is 70 m / min or more. 150 m / min or less, The manufacturing method of the foaming laminated body in any one of Claims 1-3 characterized by the above-mentioned. 4. The production of a foamed laminate according to claim 1, wherein the resin temperature when forming the (A) layer made of low-density polyethylene (a) is 240 ° C. or higher and 310 ° C. or lower. Method. When forming the (A) layer made of low-density polyethylene (a), 0.5 mg to 100 mg of ozone is sprayed per 1 m ^{2 of the} melt film made of low-density polyethylene (a) extruded from the die. The manufacturing method of the laminated body for foaming of Claim 7.