JP2014073625A - Laminate for heat foaming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene resin composition for extrusion lamination, exhibiting sufficient film formation property in extrusion laminate molding and achieving reduction in roll contamination.SOLUTION: A laminate for heat foaming contains at least a constitution of (A) layer/substrate layer/(B) layer, where the (A) layer is made of low density polyethylene, the (B) layer comprises a resin composition which are composed of 50 to 90 wt.% of (a) an ethylene-α-olefin copolymer obtained by copolymerizing ethylene having a density of 945 to 955 kg/mand MFR of 10 to 50 g/10 min. and α-olefin having 3 to 6 carbon atoms, and 10 to 50 wt.% of (b) high-pressure-processed low density polyethylene having the density of 915 to 930 kg/mand MFR of 1 to 10 g/10 min., and which satisfies following requirements (I) to (II). (I) a density of 932 to 953 kg/m(II) an MFR of 3 to 43 g/10 min.

Description

  The present invention relates to a laminate that is foamed by heating, has a thick foam layer, is excellent in heat insulation, and has both cup formability and heat resistance.

  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, by laminating a thermoplastic synthetic resin film with a low melting point on at least one surface of moisture-containing base material and heating it, the synthetic resin film is foamed into irregularities using the moisture contained in the base material. And a technique for forming a foamed layer has been devised (see, for example, Patent Documents 1 and 2). In addition, a method has been proposed in which a laminate is foamed by using a thermoplastic resin having a higher melting temperature than the foamed layer on the opposite side of the foamed layer (non-foamed layer) with respect to the base material, and heating at an intermediate temperature between the two. High density polyethylene is exemplified as the thermoplastic resin of the non-foamed layer (for example, see Patent Documents 3 to 5). Moreover, the method of using polyethylene with high melting temperature for a non-foaming layer is described (for example, refer patent document 6). However, none of the patent documents describes details of high-density polyethylene. As a method for producing a laminate, an extrusion laminate molding method is widely used because it is easy to obtain a product with high production efficiency and stable quality. However, since high-density polyethylene is inferior in moldability, it has been difficult to obtain a laminate by extrusion lamination. Therefore, a method of performing extrusion lamination by mixing high-density polyethylene with high-pressure low-density polyethylene is used. However, with this method, the hot tack property is not sufficient, and there are cases where problems such as the heat seal portion being easily peeled off or the temperature conditions being difficult to set during secondary processing.

  On the other hand, a method has been devised in which a non-foamed layer is provided with a barrier layer that suppresses permeation of water vapor, thereby improving the foaming ratio of the foamed layer. By providing a layer made of aluminum foil or stretched polyester film as a barrier layer on the opposite side of the foamed layer, and further providing a sealant layer on it, it prevents the transmission of water vapor during heat foaming while allowing cup molding by heat sealing. A method is described (for example, see Patent Documents 7 and 8). However, in this method, since it is necessary to provide a barrier layer and a sealant layer, there is a problem that the layer configuration is complicated and the cost is increased.

Japanese Patent Publication No. 48-32283 JP 2001-270571 A Japanese Patent Laid-Open No. 10-128928 Japanese Patent Laid-Open No. 11-189279 JP 2007-168178 A Japanese Patent Laid-Open No. 10-167248 JP 2003-261128 A JP 2004231197 A

  The present invention has been made in view of the situation as described above, and is excellent in productivity of a laminate, can be simplified in layer structure, has excellent heat resistance when heated and foamed, has a high expansion ratio, The object is to provide a laminate.

  As a result of intensive studies to solve the above problems, the present inventors have found that a laminate using a specific ethylene polymer exhibits excellent foamability when foamed by heating, and the present invention It came to be completed.

That is, the present invention is a laminate comprising at least (A) layer / base material layer / (B) layer, and (B) layer being the outermost layer, wherein (A) layer is composed of low-density polyethylene. is, (B) layer density 945 kg / ^{m 3} or more 955 kg / ^{m 3} or less, JIS K6922-1 (hereinafter referred to as MFR) the melt flow rate measured by the method described in (1998) 10 g / 10 minutes or more 50g / 10 min or less is ethylene and C 3 obtained by copolymerizing 6 of α- olefins ethylene -α- olefin copolymer (a) 50 to 90 wt% and a density 915 kg / ^{m 3} or more 930 kg / ^{m 3} Hereinafter, the high-pressure low-density polyethylene (b) having an MFR of 1 g / 10 min to 10 g / 10 min (b) is contained in an amount of 10 to 50 wt% (the sum of (a) and (b) is 100 wt%), and the following requirements (I) to (II) Composed of a resin composition which satisfies, to a heat foaming laminate.
(I) Density 932 kg / m ³ or more and 953 kg / m ³ or less (II) MFR ³ g / 10 min or more and 43 g / 10 min or less In addition, a method of laminating (A) layer / base material layer / (B) layer is extrusion lamination. The present invention relates to a laminate for heating and foaming, which is a molding method.

  Moreover, it is related with the foam obtained by heat-foaming said laminated body.

  The present invention is described in detail below.

  The layer (A) constituting the laminate of the present invention is mainly composed of low density polyethylene. Examples of the low density polyethylene include a high pressure method low density polyethylene, an ethylene / α-olefin copolymer, and a mixture thereof. 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, -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. Furthermore, 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 appropriately selected from commercially available products.

  When mixing a plurality of olefin polymers as low-density polyethylene, the mixing method may be any of a method of mixing pellets and powder in a solid state, a method of melt kneading with a single screw extruder, twin screw extruder, kneader, Banbury, etc. It doesn't matter. When using a melt-kneading apparatus, the temperature is not particularly limited as long as it is equal to or higher than the melting temperature, but it is preferably performed at 150 ° C. or higher and 250 ° C. or lower in order to suppress thermal deterioration and obtain a stable quality resin composition.

  In the laminate of the present invention, the melt mass flow rate (MFR) measured by JIS K6922-1 (1998) of the low density polyethylene used for the layer (A) is in the range of 4 to 100 g / 10 min. It is preferable because the laminate has excellent foamability.

In the laminated body of the present invention, the density measured by JIS K6922-1 (1998) of the low density polyethylene used for the (A) layer can reduce the amount of heat applied when foaming the laminated body. / M ³ is preferable.

In the laminate of the present invention, the melt tension at 130 ° C. (hereinafter referred to as MS _{130. The} unit is mN) of the low density polyethylene used for the layer (A) is as long as that of a capillary viscometer with a barrel diameter of 9.55 mm. 8mm, 2.095mm in diameter, 90 ° inflow dice is installed, temperature is set to 130 ° C, piston descent speed is 10mm / min, draw load is required (mN) And when MS ₁₃₀ is in the range of 80 to 180 mN, when the laminate is heated, it is preferable because a foam with excellent foaming ratio and excellent surface appearance can be obtained which is less likely to cause large unevenness on the foamed surface.

  In the laminate of the present invention, the low density polyethylene used for the layer (A) may be a resin composition in which a plurality of thermoplastic resins are mixed. Above all, when the resulting laminate is heated, a foam having a thick foam layer and a good heat insulating property can be obtained. Therefore, the low density polyethylene comprises a high pressure method low density polyethylene and an ethylene / α-olefin copolymer. Those mixed at a weight ratio of 50/50 to 99/1 are preferred.

  In the laminate of the present invention, the low density polyethylene and olefin polymer used in the layer (A) include an antioxidant, a light stabilizer, an antistatic agent, a lubricant, an antiblocking agent, etc., if necessary. You may add the additive generally used for polyolefin resin in the range which does not impair the objective of this invention.

  The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention is a repeating unit derived from ethylene and a repeating unit derived from an α-olefin having 3 to 6 carbon atoms. It is an ethylene-α-olefin copolymer. Examples of the α-olefin having 3 to 6 carbon atoms include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 3-methyl-1-butene. You may use together at least 2 types of these C3-C6 alpha olefins.

The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention has a density measured by the method described in JIS K6922-1 (1998) of 945 kg / m. ³ or more and 955 kg / m ³ or less. Here, when the density is less than 945 kg / m ³ , the heat resistance of the resin composition for extrusion lamination is inferior, which is not preferable. On the other hand, when it exceeds 955 kg / m ³ , the melting temperature of the ethylene-α-olefin copolymer is high, and the resin composition for extrusion lamination is excellent in heat resistance and rigidity, but the hot tack property is deteriorated. Absent. The density can be measured by a density gradient tube method in accordance with JIS K6922-1 (1998).

  The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention has a melt flow rate (hereinafter referred to as “the melt flow rate”) measured by the method described in JIS K6922-1 (1998). MFR) is 10 g / 10 min to 50 g / 10 min, preferably 10 g / 10 min to 50 g / 10 min. Here, when the MFR is less than 10 g / 10 min, the load on the extruder when making the resin composition for extrusion lamination is increased, the productivity is lowered, and the drawdown (upper limit of take-up speed) is inferior. Absent. On the other hand, when it exceeds 50 g / 10 minutes, the neck-in (decrease in the width of the molten film) becomes large, and the extrusion laminate formability may be inferior.

The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention preferably has a long chain branch in the structure. By having a long chain branch in the structure, the melt tension of the ethylene-α-olefin copolymer (a) is increased, and the laminate processability of the resin composition for extrusion lamination is improved. Furthermore, when having 0.01 to 0.04 long-chain branches having 1000 or more carbon atoms per 1000 carbon atoms, the balance between neck-in and draw-down during lamination is excellent, and the layer (B) is made thin It is preferable because of its excellent molding stability. The number of long-chain branches is the number of branches of hexyl groups or more (6 or more carbon atoms) detected by ¹³ C-NMR measurement.

Furthermore, the ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention is in the presence of a macromonomer that satisfies the following requirements (iii) to (v), or A polyethylene polymer obtained by polymerizing ethylene, a macromonomer, and optionally an olefin having 3 to 6 carbon atoms simultaneously with the synthesis of the macromonomer is desirable.
(Iii) obtained by polymerizing ethylene or copolymerizing ethylene and an olefin having 3 to 6 carbon atoms and having a vinyl group at the terminal (iv) a number average molecular weight (Mn) of 2000 or more (v) a weight average molecular weight ( Mw) to number average molecular weight ratio Mw / Mn is 2 to 5
A macromonomer is an olefin polymer having a vinyl group at the end, preferably an ethylene polymer having a vinyl group at the end obtained by polymerizing ethylene, or a copolymer of ethylene and an olefin having 3 to 6 carbon atoms. It is an ethylene copolymer having a vinyl group at the terminal obtained by the process.

  Examples of the olefin having 3 to 6 carbon atoms include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-butene, α-olefin such as vinylcycloalkane, butadiene or 1,4 -A diene such as hexadiene can be exemplified. Two or more of these olefins can be mixed and used.

  When an ethylene polymer having a vinyl group at the terminal or an ethylene copolymer having a vinyl group at the terminal is used as the macromonomer, the number average molecular weight (Mn) in terms of linear polyethylene is 2,000 or more, Preferably it is 5,000 or more, More preferably, it is 10,000 or more. The weight average molecular weight (Mw) in terms of linear polyethylene is 4,000 or more, preferably 10,000 or more, more preferably more than 15,000. By increasing the molecular weight of the macromonomer, the length of the long chain branch introduced into the ethylene-α-olefin copolymer (a) is increased, and the melt tension is increased, thereby reducing the neck-in. The ratio of the weight average molecular weight (Mw) to Mn (Mw / Mn) is 2 or more and 5 or less, preferably 2 or more and 4 or less, more preferably 2 or more and 3.5 or less. By narrowing the molecular weight distribution of the macromonomer, the length of the long chain branch introduced into the ethylene-α-olefin copolymer (a) becomes substantially constant, the melt tension increases, and the neck-in decreases.

  The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention has a weight average molecular weight (Mw) to number average molecular weight ratio Mw / Mn in the range of 2 to 5. It is desirable to be in Mw / Mn can be calculated by measuring the weight average molecular weight (Mw) and the number average molecular weight (Mn), which are standard polyethylene equivalent values, by gel permeation chromatography (GPC). When Mw / Mn is in this range, the content ratio of the low molecular weight component in the resin is small, so roll contamination during lamination molding due to leaching of the low molecular weight component, stickiness of the surface of the laminate molded product, heat seal failure, etc. The adverse effect is suppressed, and at the same time, the extrusion load becomes higher than necessary, and the amount of extrusion during lamination is not limited.

  The ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention may be obtained by any method, for example, production of Examples described later. It can be arbitrarily created by fine adjustment of the conditions themselves or the condition factors.

  The catalyst used for the copolymerization of ethylene and α-olefin is not particularly limited, and a Ziegler catalyst, a Phillips catalyst, a metallocene catalyst, or the like can be used. Preferably, the catalyst is polymerized by a metallocene catalyst.

  When producing an ethylene-α-olefin copolymer (a) using a metallocene catalyst, the metallocene catalyst to be used has a metallocene complex, an activation co-catalyst, and, if necessary, an organoaluminum compound as constituent components, Simultaneously with the synthesis of the macromonomer, it is preferable to carry out copolymerization of the macromonomer, ethylene and optionally an olefin having 3 to 6 carbon atoms.

As a metallocene catalyst for synthesizing a macromonomer and copolymerizing a macromonomer, ethylene, and optionally an olefin having 3 to 6 carbon atoms, a metallocene complex, a non-bridged bis (indenyl) zirconium complex, a non-bridged bis (cyclo Pentadienyl) zirconium complex, bridged bis (cyclopentadienyl) zirconium complex, bridged bis (indenyl) zirconium complex, bridged (cyclopentadienyl) (indenyl) zirconium complex, bridged (cyclopentadienyl) A catalyst using a (fluorenyl) zirconium complex or a cross-linked (indenyl) (fluorenyl) zirconium complex is preferred.
Specific examples of metallocene complexes include, for example, bis (indenyl) zirconium dichloride, dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (indenyl) zirconium dichloride, dimethylsilanediyl (cyclopenta). Dienyl) (2-methylindenyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (4,7-dimethylindenyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (2,4,7- Trimethylindenyl) zirconium dichloride, diphenylmethylene (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (1-cyclopenta Dichlorides such as enyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, isopropylidene (1-cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride Examples of the transition metal compound include dimethyl, diethyl, dihydro, diphenyl, and dibenzyl. Moreover, although the compound which substituted the zirconium atom of the said transition metal compound with the titanium atom or the hafnium atom can also be illustrated, it is not limited to these. Among these, you may use 1 type or multiple types.

  The activation co-catalyst used as a component of the metallocene catalyst is a metallocene complex or a compound that plays a role in converting a reaction product of a metallocene complex and an organoaluminum compound into an active species capable of olefin polymerization. It is preferable that it is a compound which produces | generates a reactive compound, and the produced | generated cationic compound acts as a polymerization active seed | species which can superpose | polymerize an olefin. An activation co-catalyst is a compound that provides a compound that, after forming a polymerization active species, coordinates weakly or interacts with the generated cationic compound, but does not react directly with the active species.

  Specific examples of the activation promoter include alkylaluminoxanes such as methylaluminoxane, silica gel-supported alkylaluminoxanes, tris (fluorinated aryl) borons such as tris (pentafluoreophenyl) boron, N, N-dimethylammonium-tetrakis ( Examples thereof include boron compounds such as tetrakis (fluorinated aryl) boron salts such as pentafluorophenyl) boron, silica gel-supported materials thereof, clay minerals, clay minerals treated with organic compounds, and the like. Among them, it is preferable to use a clay mineral treated with an organic compound.

  When a clay mineral treated with an organic compound is used as the activation promoter, the clay mineral used is preferably a clay mineral belonging to the smectite group, and specific examples include montmorillonite, beidellite, saponite, hectorite and the like. It is also possible to use a mixture of a plurality of these clay minerals.

  The organic compound treatment means introducing an organic ion between clay mineral layers to form an ionic complex.

  Examples of the organic compound used in the organic compound treatment include N, N-dimethyl-n-octadecylamine hydrochloride, N, N-dimethyl-n-eicosylamine hydrochloride, N, N-dimethyl-n-docosylamine hydrochloride, N, N-dimethyloleylamine hydrochloride, N, N-dimethylbehenylamine hydrochloride, N-methyl-bis (n-octadecyl) amine hydrochloride, N-methyl-bis (n-eicosyl) amine hydrochloride, N-methyl -Alkylammonium salts such as dioleylamine hydrochloride, N-methyl-dibehenylamine hydrochloride, N, N-dimethylaniline hydrochloride can be exemplified.

The metallocene catalyst is not particularly limited in the method for preparing the metallocene catalyst such as a method in which a metallocene complex is reacted with an activation promoter.
As the metallocene catalyst, an alkylaluminum such as triethylaluminum or triisobutylaluminum may be used as necessary for the activation of the metallocene complex and the removal of impurities in the solvent during the preparation of the catalyst.

  When producing the ethylene-α-olefin copolymer (a) which is a component of the polyethylene resin composition for extrusion lamination of the present invention, it is preferable to carry out at a polymerization temperature of −100 to 120 ° C., particularly considering productivity. Then, 20-120 degreeC is preferable, and also it is preferable to carry out in 60-120 degreeC. The polymerization time is preferably in the range of 10 seconds to 20 hours, and the polymerization pressure is preferably in the range of normal pressure to 300 MPa. The polymerizable monomer is ethylene and an α-olefin having 3 to 6 carbon atoms, and the supply ratio of ethylene and the α-olefin having 3 to 6 carbon atoms is ethylene / α-olefin having 3 to 6 carbon atoms ( A feed ratio of 1 to 200, preferably 3 to 100, and more preferably 5 to 50 can be used. It is also possible to adjust the molecular weight using hydrogen during polymerization. The polymerization can be carried out by any of batch, semi-continuous and continuous methods, and can be carried out in two or more stages by changing the polymerization conditions. In addition, the ethylene copolymer can be obtained by separating and recovering from the polymerization solvent by a conventionally known method after the completion of the polymerization and drying.

  Polymerization can be carried out in a slurry state, a solution state, or a gas phase state. In particular, when the polymerization is performed in a slurry state, an ethylene-based copolymer having a powder particle shape is efficiently and stably produced. Can do.

  The number of long chain branches of the ethylene-α-olefin copolymer (a) constituting the resin composition contained in the layer (B) of the present invention can be increased by increasing the number of terminal vinyls of the macromonomer. The number of terminal vinyls of the macromonomer can be controlled by selecting a metallocene complex.

  Similarly, Mw / Mn of the ethylene-α-olefin copolymer (a), which is a component of the polyethylene resin composition for extrusion lamination of the present invention, can be controlled by selecting a metallocene complex.

  The high-pressure method low-density polyethylene (b) constituting the resin composition contained in the layer (B) of the present invention can be obtained by a conventionally known high-pressure radical polymerization method, and is appropriately selected within the scope of the present invention.

High-pressure low-density polyethylene constituting the resin composition contained in the (B) layer (b) of the present invention, JIS K6922-1 density measured by the method (1998) of 915 kg / ^{m 3} or more 930 kg / ^{m 3} or less, preferably those 915 kg / ^{m 3} or more 925 kg / ^{m 3} or less of. When the density is less than 915 kg / m ³ , the heat resistance of the resin composition for extrusion lamination of the present invention may be lowered. On the other hand, when the density is higher than 930 kg / m ³ , the melting temperature of the high-pressure low-density polyethylene is high, and the extrusion laminating resin composition is excellent in heat resistance and rigidity, but is inferior in laminating workability.

  The high-pressure low-density polyethylene (b) constituting the resin composition contained in the layer (B) of the present invention has an MFR measured by the method of JIS K6922-1 (1998) of 1 g / 10 min or more and 10 g / 10 min. In the following, it is preferably 1 g / 10 min or more and 5 g / 10 min or less. Here, when the MFR is less than 1 g / 10 min, the extrusion load at the time of laminating the resin composition for extrusion laminating is increased, productivity is lowered, and the drawdown is inferior. On the other hand, if it exceeds 10 g / 10 minutes, the melt tension becomes small and the neck-in at the time of lamination increases, which is not preferable.

  The resin composition contained in the layer (B) in which a specific amount of the ethylene-α-olefin copolymer (a) and the high-pressure method low-density polyethylene (b) satisfying the above requirements is blended is formed into a laminate by extrusion lamination. Excellent balance between heat resistance and hot tack. The resin composition contained in the layer (B) of the present invention comprises an ethylene-α-olefin copolymer (a) of 50 to 90% by weight, preferably 50 to 70% by weight, and high pressure method low density polyethylene (b) 10 -50% by weight, preferably 30-50% by weight. When the blending amount of the high-pressure low-density polyethylene (b) is less than 10% by weight, the melt tension of the resin composition for extrusion lamination is decreased, and the neck-in at the time of laminating is increased. When it exceeds%, the density of the resin composition for extrusion lamination becomes low, and the heat resistance of the layer (B) and the expansion ratio of the laminate are inferior.

  The resin composition contained in the layer (B) of the present invention has an MFR measured by the method of JIS K6922-1 (1998) of 3 g / 10 min to 43 g / 10 min, preferably 7 g / 10 min. 30 g / 10 min or less, more preferably 7 g / 10 min or more and 15 g / 10 min or less. When the MFR is less than 3 g / 10 minutes, the drawdown at the time of laminating may be inferior, which is not preferable. On the other hand, when MFR exceeds 43 g / 10 minutes, the neck-in at the time of a lamination process becomes large and is not preferable.

The resin composition contained in the layer (B) of the present invention has a density measured by the method described in JIS K6922-1 (1998) of 932 kg / m ³ or more and 953 kg / m ³ or less, preferably 932 kg / m ³ or more and 945 kg / m ³ or less. When the density is less than 932 kg / m ^3, the heat resistance of the layer (B) and the expansion ratio of the laminate may be inferior, which is not preferable. On the other hand, when the density exceeds 953 kg / m ³ , the hot tack property may be inferior.

  In the resin composition contained in the layer (B) of the present invention, a stabilizer, a lubricant, a flame retardant, a dispersing agent, a filler, a foaming agent, a foaming nucleus are included in the range not departing from the gist of the present invention. An agent, a crosslinking agent, an ultraviolet ray inhibitor, an antioxidant, a colorant and the like can be contained. Moreover, it can be used by mixing with other thermoplastic resins.

  The resin composition for extrusion laminating according to the present invention can be prepared by a method usually used as a resin composition. For example, as a melting / mixing method, extrusion kneading using a single screw extruder or twin screw extruder, roll kneading. And the like, and can be obtained by melt-kneading by this method.

  The laminate of the present invention has at least (A) layer / base material layer / (B) layer in this order, and has a configuration in which the (B) layer is the outermost layer. Moreover, you may print on the surface of (A) layer and (B) layer. Moreover, a barrier layer etc. can be provided between a base material layer and (B) layer. However, since the layer which comprises a laminated body can be decreased, the laminated body has the preferable structure of (A) layer / base material layer / (B) layer.

  In the laminate of the present invention, examples of the method of laminating the (A) layer, the base material layer, and the (B) layer include an extrusion laminate molding method, a dry laminate molding method, and a press molding method. Among them, the extrusion lamination molding method is preferable because of high production efficiency and easy stabilization of the quality of the molded laminate. Examples of the extrusion laminating method include a single laminating method, a tandem laminating method, a sandwich laminating method, and a coextrusion laminating method.

As a base material constituting such a laminate of the present invention, kraft paper, kurpack paper, fine paper, glassine paper, paper mainly composed of natural pulp such as paperboard, and woven made of synthetic fibers such as nylon and polyester fibers Examples include cloth, cloth cloth, foamed sheets made of thermoplastic resins such as polyethylene and polyurethane, and sheets in which porous inorganic materials such as zeolite are mixed with thermoplastic resins. Among them, the amount of moisture contained in the substrate Paperboard is preferred because it is relatively easy to adjust. Moreover, the base material may be printed with colored ink etc. by a conventionally well-known technique. When using the paperboard substrate, excellent moldability during molding into a container, since the more easy to adjust the water content, basis weight 150~500g / ^{m 2,} more preferably 200 to 400 g / ^{m 2} It is preferable that

The moisture contained in the substrate constituting the laminate of the present invention is preferably 10 to 40 g / m ² , more preferably 20 to 35 g / m ² . When the moisture content is in this range, the foamed layer is thick when the laminate is foamed, and it is also preferable because large irregularities on the foamed surface due to bonding of foamed cells and foam breakage are unlikely to occur.

Further, in the extrusion laminating process, immediately after the material of the layer (A) or the layer (B) 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, It is preferable to use a bonding method because of excellent adhesion to 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 order to further improve the adhesion between the (A) layer or the (B) layer and the base material layer, the laminate of the present invention has a temperature at which the polyethylene-based resin does not foam, for example, 10 to 30 ° C to 60 ° C. It can be heat-treated for more than an hour. Moreover, you may perform well-known surface treatments, such as a corona treatment, a flame treatment, and a plasma treatment, to the adhesion surface of a base material as needed. If necessary, an anchor coating agent may be applied to the substrate.

  In the laminate of the present invention, the thickness of the layer (A) is not particularly limited as long as the object of the present invention is achieved, and is excellent in foaming properties and has few problems such as breakage. Therefore, the thickness is 30 μm to 450 μm. It is preferable that the range is 30 μm to 150 μm from the viewpoint of economy.

  Further, in the laminate of the present invention, the thickness of the layer (B) is not particularly limited as long as the object of the present invention is achieved, and the thickness of the layer is 10 μm to 200 μm because problems of curling and gas barrier properties are small. The range of 10 μm to 60 μm is most preferable from the viewpoint of economy.

  Although the heating temperature and heating time in foam molding vary depending on the base material used and the type of thermoplastic resin, the heating temperature is generally 110 ° C. to 200 ° C., and the heating time is 10 seconds to 5 seconds. For minutes.

  The 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 by heating and foaming.

  The laminate of the present invention is easily foamed by heating, large irregularities are hardly formed on the surface after foaming, the surface appearance is good, the heat sealing of the non-foamed layer is easy, and the cup moldability is good. It is an excellent laminate from which a foamed laminate can be obtained.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

-Measurement of molecular weight and molecular weight distribution-
The weight average molecular weight (Mw), the number average molecular weight (Mn), and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of the macromonomer and the ethylene-α-olefin copolymer (a) are determined by gel permeation. Measured by chromatography (GPC). Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC apparatus, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 140 ° C., and 1 is used as the eluent. Measurement was performed using 2,4-trichlorobenzene. A measurement sample was prepared at a concentration of 1.0 mg / ml, and 0.3 ml was injected and measured. The calibration curve of molecular weight is calibrated using a polystyrene sample having a known molecular weight. In addition, Mw and Mn were calculated | required as a value of linear polyethylene conversion.

~ Measurement of density ~
The density was measured by a density gradient tube method in accordance with JIS K6922-1 (1998).

~ Measurement of MFR ~
MFR was measured with a melt indexer based on JIS K6922-1 (1998).

-Measurement of the number of long chain branches-
The number of long chain branches of the ethylene-α-olefin copolymer (a) was measured by ¹³ C-NMR using a Varian VNMRS-400 type nuclear magnetic resonance apparatus. The solvent is tetrachloroethane -d _2. The number per 1,000 main chain methylene carbons was determined from the following formula (4) described in “Macromolecules” Vol. 31, No. 25, pages 8679-8683 (1998).

Number of long chain branches = IA _α / (3 × IA _tot ) (4)
[Wherein, IA _α is the integrated intensity of a long-chain branched α-carbon peak (chemical shift: 34.6 ppm) above the hexyl group, and IA _tot is the integrated intensity of the main chain methylene carbon peak (30.0 ppm). It is. ]
~ Measurement of melt tension ~
A capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) with a barrel diameter of 9.55 mm was equipped with a die having a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 °. The temperature was set to 130 ° C., the piston lowering speed was set to 10 mm / min, the stretch ratio was set to 47, and the load (mN) required for take-up was taken as the melt tension. The measurement was performed in a constant temperature room set at 23 ° C.

~ Neck-in ~
(B) The resin composition of the layer is supplied to an extruder of an extrusion laminator (manufactured by Musashinokikai Co., Ltd.) having a 90 mmφ screw, and is extruded from a T die having an opening width of 600 mm at a temperature of 315 ° C. T die opening width and extrusion laminating resin composition when extrusion lamination is performed on a kraft paper substrate having a basis weight of 50 g / m ² and a thickness of 20 μm. The difference from the coat width was determined as neck-in, and the value was measured. The smaller the neck-in, the better. The evaluation was ○ for 79 mm or less and x for 80 mm or more.

~ Drawdown ~
(B) The resin composition of the layer is supplied to an extruder of an extrusion laminator (manufactured by Musashinokikai Co., Ltd.) having a 90 mmφ screw, and is extruded from a T die having an opening width of 600 mm at a temperature of 315 ° C. The film end stability was evaluated when extrusion lamination was performed on a kraft paper substrate having a basis weight of 50 g / m ^{2 so that} the resin composition for extrusion lamination had a thickness of 10 μm. When the film edge was stable, the film edge was stable. The film edge was shaken. The film edge was shaken. The film edge was shaken greatly and the film was not formed. .

-Heat resistance (pinhole)-
The laminates obtained in the examples were cut into 20 cm × 30 cm, allowed to stand for 150 seconds in a small oven heated to 120 ° C. (manufactured by Werner Mathis AG), then taken out and cooled to room temperature in air. A sample of the laminated body after foaming was taken, and it was confirmed whether or not pinholes were generated on the surface of the (B) layer. The case where no pinhole was generated was evaluated as ◯, and the case where a pinhole was generated was evaluated as ×.

~ Hot tackiness ~
Using a hot tack tester (manufactured by Tester Sangyo Co., Ltd.), the laminate obtained in the examples was stacked in two pieces so that the (B) layer surface was in contact with the inside, and heated on both sides. Immediately after heat sealing with a seal bar having a pressure of 0.2 MPa, a sealing time of 2 seconds and a width of 10 mm and a length of 300 mm, T peeling (180 °) was performed with a weight (45 g each) attached to the end of the laminate. It was. Measurement was performed at a seal temperature of 100 to 200 ° C. (at intervals of 10 ° C.), and the peeled distance of the seal portion was measured. A value obtained by subtracting the upper limit temperature and the lower limit temperature at which the peeling distance was 90 mm or less was defined as a sealable temperature range. The wider the sealable temperature range, the better. The sealable temperature range of 40 ° C. or higher was evaluated as ◯, and the temperature of 30 ° C. or lower was evaluated as ×.

~ Thickness of foam layer ~
The laminates obtained in the examples were cut into 20 cm × 30 cm, allowed to stand for 150 seconds in a small oven heated to 120 ° C. (manufactured by Werner Mathis AG), then taken out and cooled to room temperature in air. A sample of the laminate after foaming was taken, and a cross-sectional photograph was taken with an optical microscope. The thickness of the foamed layer was measured from the cross-sectional photograph, and the case where the thickness of the average foamed layer measured at five locations was 500 μm or more was evaluated as “◯”, and less than 500 μm was evaluated as “x”.

Synthesis Example 1 [Production of ethylene-α-olefin copolymer (a-1)]
(1) Denaturation of clay In 6 liters of distilled water, 150 g of concentrated hydrochloric acid, 642 g (1.2 mol) of methyldioleilamine (Lion Corporation (trade name) Armin M2O) and synthetic hectorite (trade name, manufactured by Rockwood Additives) (trade name) After adding 1 kg of Laponite RD), the mixture was heated to 60 ° C. and stirred for 1 hour while maintaining the temperature. This slurry was filtered, washed twice with 6 liters of distilled water at 60 ° C., and dried in an oven at 85 ° C. for 12 hours to obtain 1.4 kg of organically modified clay. This organically modified clay was crushed by a jet mill to have a median diameter of 15 μm.
(2) Preparation of catalyst suspension After substituting a 5 liter flask equipped with a thermometer and a reflux tube with nitrogen, 500 g of the modified clay obtained in (1) and 3.1 liter of hexane were added, and then bis (indenyl). ) Zirconium dichloride 7.06 g, isopropylidene (cyclopentadienyl) (2,7-di-tert-butyl-9-fluorenyl) zirconium dichloride 1.09 g and 20% triisobutylaluminum 1.4 l Stir at 0 ° C. for 3 hours. After cooling to 45 ° C., the supernatant was extracted, washed 5 times with 4 liters of hexane, and then added with 4 liters of hexane to obtain a catalyst suspension (solid weight: 11.0 wt%).
(3) Production of ethylene-α-olefin copolymer (a-1) A polymerizer having an internal volume of 540 L was charged with 145 kg / hour of hexane, 30 kg / hour of ethylene, 1.1 kg / hour of butene-1 and hydrogen. The catalyst suspension prepared in the above (2) was continuously fed so that the production amount was 50 NL / hour and the polymer production amount was 30 kg / hour, and the total pressure was 3,000 kPa and the polymerization vessel internal temperature was kept at 80 ° C. A polymerization reaction was performed. The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (a-1) powder. This was melt-kneaded using a single-screw extruder with a diameter of 50 mm set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (a-1) pellets. The density of the obtained ethylene-α-olefin copolymer (a-1) pellets was 945 kg / m ³ , MFR was 35 g / 10 min, the number of long chain branches was 0.03 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 2.5.

Synthesis Example 2 [Production of ethylene-α-olefin copolymer (a-2)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Synthesis Example 1 was performed.
(3) Production of ethylene-α-olefin copolymer (a-2) A polymerizer having an internal volume of 540 L was charged with 145 kg / hour of hexane, 30 kg / hour of ethylene, 0.4 kg / hour of butene-1 and hydrogen. The catalyst suspension prepared in the above (2) was continuously supplied so that the production amount was 60 NL / hour and the polymer production amount was 30 kg / hour, and the total pressure was 3,000 kPa and the polymerization vessel internal temperature was kept at 80 ° C. A polymerization reaction was performed. The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (a-2) powder. This was melt-kneaded using a single-screw extruder having a diameter of 50 mm set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (a-2) pellets. The density of the obtained ethylene-α-olefin copolymer (a-2) pellets was 955 kg / m ³ , MFR was 38 g / 10 min, the number of long chain branches was 0.02 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 2.3.

Synthesis Example 3 [Production of ethylene-α-olefin copolymer (a-3)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Synthesis Example 1 was performed.
(3) Production of ethylene-α-olefin copolymer (a-3) In a polymerization vessel having an internal volume of 540 L, hexane was 145 kg / hour, ethylene was 30 kg / hour, butene-1 was 1.0 kg / hour, and hydrogen was added. The catalyst suspension prepared in the above (2) was continuously supplied so that the production amount of 35 NL / hour and the polymer production was 30 kg / hour, and the total pressure was 3,000 kPa and the polymerization vessel internal temperature was kept at 80 ° C. A polymerization reaction was performed. Slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (a-3) powder. This was melt-kneaded using a single-screw extruder having a diameter of 50 mm set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (a-3) pellets. The density of the obtained ethylene-α-olefin copolymer (a-3) pellets was 945 kg / m ³ , MFR was 11 g / 10 min, the number of long chain branches was 0.03 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 2.5.

Synthesis Example 4 [Production of ethylene-α-olefin copolymer (a-4)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Synthesis Example 1 was performed.
(3) Production of ethylene-α-olefin copolymer (a-4) A polymerizer having an internal volume of 540 L was charged with 145 kg / hour of hexane, 30 kg / hour of ethylene, 1.6 kg / hour of butene-1 and hydrogen. The catalyst suspension prepared in the above (2) was continuously fed so that the production amount of 45 NL / hour and the polymer production amount was 30 kg / hour, and the total pressure was 3,000 kPa and the polymerization vessel internal temperature was kept at 80 ° C. A polymerization reaction was performed. The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (a-4) powder. This was melt-kneaded using a 50 mm diameter single screw extruder set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (a-4) pellets. The density of the obtained ethylene-α-olefin copolymer (a-4) pellets was 940 kg / m ³ , MFR was 35 g / 10 min, the number of long chain branches was 0.03 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 2.5.

Synthesis Example 5 [Production of ethylene-α-olefin copolymer (a-5)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Synthesis Example 1 was performed.
(3) Production of ethylene-α-olefin copolymer (a-5) A polymerizer having an internal volume of 540 L was charged with 145 kg / hour of hexane, 30 kg / hour of ethylene, 0.2 kg / hour of butene-1 and hydrogen. The catalyst suspension prepared in the above (2) was continuously supplied so that the production amount was 65 NL / hour and the polymer production amount was 30 kg / hour, and the total pressure was 3,000 kPa and the polymerization vessel internal temperature was kept at 80 ° C. A polymerization reaction was performed. The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (a-5) powder. This was melt-kneaded using a single-screw extruder having a diameter of 50 mm set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (a-5) pellets. The density of the obtained ethylene-α-olefin copolymer (a-5) pellets was 960 kg / m ³ , MFR was 35 g / 10 min, the number of long chain branches was 0.02 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 2.3.

Synthesis Example 6 [Production of ethylene-α-olefin copolymer (a-6)]
[Preparation of modified hectorite]
After adding 3 liters of ethanol and 100 ml of 37% concentrated hydrochloric acid to 3 liters of water, 330 g (1.1 mol) of N, N-dimethyl-octadecylamine was added to the resulting solution and heated to 60 ° C. A hydrochloride solution was prepared. 1 kg of hectorite was added to this solution. The suspension was stirred at 60 ° C. for 3 hours, the supernatant was removed, and then washed with 50 L of 60 ° C. water. Then, it dried at 60 degreeC and 10 < ^-3 > torr for 24 hours, and the modified | denatured hectorite with an average particle diameter of 5.2 micrometers was obtained by grind | pulverizing with a jet mill.
[Preparation of polyethylene production catalyst]
500 g of the modified hectorite prepared in [Preparation of modified hectorite] is suspended in 1.8 liters of hexane, 2.9 liters of a hexane solution of triisobutylaluminum (0.714 M) is added, and the mixture is stirred at room temperature for 1 hour. As a result, a contact product of modified hectorite and triisobutylaluminum was obtained. On the other hand, a catalyst slurry (100 g / L) was obtained by adding dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride 6.97 g (20 mmol) dissolved in toluene and stirring overnight at room temperature. .
[Manufacture of macromonomer]
Into a polymerization vessel having an internal volume of 540 liters, 300 liters of hexane and 7.6 liters of 1-butene were introduced, and the internal temperature of the autoclave was raised to 85 ° C. 135 ml of the polyethylene production catalyst was added to the autoclave, and ethylene gas was introduced until the ethylene partial pressure reached 1.2 MPa to initiate polymerization. The polymerization temperature was controlled at 85 ° C. During the polymerization, ethylene gas was continuously introduced so that the partial pressure was maintained at 1.2 MPa. 90 minutes after the start of polymerization, the internal pressure of the polymerization vessel was released to obtain a macromonomer. The macromonomer extracted from the polymerization vessel had Mn = 10,950, Mw / Mn = 2.61, and Z = 0.57.
[Production of ethylene polymer]
In the polymerization vessel containing the macromonomer produced above and having an internal volume of 540 liters, 0.22 liter of 1-butene, 0.75 liter of a hexane solution of triisobutylaluminum (0.714 mol / L) and diphenylmethylene (1- Indenyl) (9-fluorenyl) zirconium dichloride (3.75 mmol) was introduced, and the internal temperature of the autoclave was raised to 85 ° C. Polymerization was started by introducing an ethylene / hydrogen mixed gas (hydrogen: 22,000 ppm) until the partial pressure reached 0.2 MPa. During the polymerization, an ethylene / hydrogen mixed gas was continuously introduced so that the partial pressure was maintained at 0.2 MPa. The polymerization temperature was controlled at 85 ° C. After 90 minutes from the start of the polymerization, the internal pressure of the autoclave was released, and the contents were suction filtered. After drying, 54 kg of a polyethylene resin was obtained. The density of the obtained polyethylene resin is 948 kg / m ³ , the MFR is 30 g / 10 min, the number of long chain branches is 0.15 per 1000 carbon atoms, and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) Mw / Mn was 2.6.

下記実施例および比較例で（Ｂ）層の樹脂組成物に用いた高圧法低密度ポリエチレン、高密度ポリエチレンの特性を表２に示す。

Table 2 shows the characteristics of the high-pressure method low-density polyethylene and high-density polyethylene used for the resin composition of the layer (B) in the following examples and comparative examples.

下記実施例および比較例で（Ａ）層に用いた低密度ポリエチレンの特性を表３に示す。

Table 3 shows the characteristics of the low density polyethylene used for the layer (A) in the following Examples and Comparative Examples.

実施例１
合成例１に示したエチレン−α−オレフィン共重合体（ａ−１）６０重量％、高圧ラジカル重合法で得られた低密度ポリエチレン（東ソー（株）製 商品名ペトロセン ３６０；密度９１９ｋｇ／ｍ^３、ＭＦＲ１．６ｇ／１０分）（以下、（ｂ−１）という。）４０重量％をタンブラーミキサーにて予備混合した後、シリンダー温度１８０℃に調整した単軸押出機（（株）プラコー製、型式 ＰＤＡ−５０）で溶融混練、造粒し、（Ｂ）層に用いる樹脂組成物のペレットを得た。

Example 1
60% by weight of the ethylene-α-olefin copolymer (a-1) shown in Synthesis Example 1, low-density polyethylene obtained by a high-pressure radical polymerization method (trade name Petrocene 360 manufactured by Tosoh Corp .; density 919 kg / m ³ , MFR 1.6 g / 10 min) (hereinafter referred to as (b-1)) 40 wt% was premixed with a tumbler mixer, and then a single screw extruder adjusted to a cylinder temperature of 180 ° C. (manufactured by Plako Co., Ltd., The mixture was melt-kneaded and granulated with a model PDA-50) to obtain pellets of a resin composition used for the layer (B).

Using the resin composition used for the layer (B), the neck-in was measured by the method shown in the evaluation method. Furthermore, the pellet of the resin composition used for the layer (B) is supplied to a single screw extrusion laminator (manufactured by Musashinokikai Co., Ltd.) having a screw having a diameter of 90 mmφ, and is extruded from a T die at a temperature of 315 ° C. m ^2, and was subjected to extrusion lamination molding to a thickness of 20μm a paper substrate on a basis weight of 300 g / ^{m 2.} Further, on the back side of the base material layer with respect to the polyethylene-based resin layer of this laminate, a high-pressure low-density polyethylene having a MFR of 8 g / 10 min and a density of 919 kg / m ³ (trade name Petrocene 203, manufactured by Tosoh Corporation), A -1) is formed using the same extrusion laminator so as to have a thickness of 70 μm, and a laminate is obtained in which the (A) layer, the base material layer, and the (B) layer are laminated in this order. The cooling roll was a semi-mirror roll, and the substrate surface was subjected to corona discharge treatment under the condition of 100 W · min / m ² immediately before laminating the low-density polyethylene and ethylene polymer on the substrate. Using this laminate, hot tack measurement, heat resistance measurement, and foam layer thickness measurement were performed. The results are shown in Table 4.

Example 2
Resin composition pellets were obtained in the same manner as in Example 1 except that the blending ratio of the resin composition of the B layer was changed to 90 wt% a-1 and 10 wt% B-1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 3
Resin composition pellets were obtained in the same manner as in Example 1 except that the blending ratio of the resin composition of the B layer was changed to a-1 50 wt% and B-1 50 wt%. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 4
Example except that ethylene-α-olefin copolymer a-2 shown in polymerization example 2 was used instead of a-1 as the ethylene-α-olefin copolymer contained in the resin composition of layer (B) In the same manner as in No. 1, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 5
Example except that ethylene-α-olefin copolymer a-3 shown in polymerization example 3 was used instead of a-1 as the ethylene-α-olefin copolymer contained in the resin composition of layer (B) In the same manner as in No. 2, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 6
(B) High pressure method low density polyethylene b-2 (trade name Petrocene 213, manufactured by Tosoh Corporation); density 918 kg / m ³ , MFR 8 g / in place of b-1 as the high pressure method low density polyethylene contained in the resin composition of the layer Resin composition pellets were obtained in the same manner as in Example 3, except that 10 minutes) was used. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 7
(B) As a high-pressure method low-density polyethylene contained in the resin composition of the layer, instead of B-1, high-pressure method low-density polyethylene b-3 (trade name Petrocene 205 manufactured by Tosoh Corp .; density 924 kg / m ³ , MFR ³ g / Resin composition pellets were obtained in the same manner as in Example 3, except that 10 minutes) was used. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

Example 8
(A) As the low density polyethylene used for the layer, MFR 8 g / 10 min, high pressure method low density polyethylene (trade name Petrocene 203 manufactured by Tosoh Corporation) having a density of 919 kg / m ³ , MFR 14 g / 10 min, density 902 kg / m ³ 1-hexene copolymer (trade name Nipolon-Z04P67D manufactured by Tosoh Corporation) was mixed at a weight ratio of 85/15 and melted at 180 ° C. with a twin screw extruder (TEX30SS manufactured by Nippon Steel). The laminate was molded and evaluated in the same manner as in Example 1 except that low-density polyethylene (referred to as A-2) obtained by kneading was used. The results are shown in Table 4.

比較例１
（Ｂ）層の樹脂組成物に含まれるエチレン−α−オレフィン共重合体としてａ−１の代わりに重合例４に示したエチレン−α−オレフィン共重合体ａ−４を使用した以外は実施例１と同様にして樹脂組成物のペレットを得た。得られたペレットを用いて、実施例１と同様にラミネート成形し評価を行った。これらの評価結果を表５に示す。

Comparative Example 1
Example except that ethylene-α-olefin copolymer a-4 shown in polymerization example 4 was used instead of a-1 as the ethylene-α-olefin copolymer contained in the resin composition of layer (B). In the same manner as in No. 1, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained laminate had pinholes and was inferior in heat resistance. Moreover, the foam layer thickness was thin.

Comparative Example 2
Example except that ethylene-α-olefin copolymer a-5 shown in polymerization example 5 was used instead of a-1 as the ethylene-α-olefin copolymer contained in the resin composition of layer (B) In the same manner as in No. 1, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained laminate had a narrow sealable temperature range and was inferior in hot tack property.

Comparative Example 3
(B) High-pressure method low-density polyethylene b-4 (trade name Petrocene 212 manufactured by Tosoh Corporation); density 919 kg / m ³ instead of b-1 as the high-pressure method low-density polyethylene (b) contained in the resin composition of the layer , MFR 13 g / 10 min) was used in the same manner as in Example 1 to obtain resin composition pellets. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained resin composition of the (B) layer had a large neck-in and was inferior in laminate processability.

Comparative Example 4
(B) Resin composition pellets were obtained in the same manner as in Example 1 except that the high-pressure low-density polyethylene (b) was not blended in the resin composition of the layer and the blending ratio was changed to a-2 100% by weight. It was. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

    The obtained resin composition of the (B) layer had a large neck-in and was inferior in laminate processability. Further, the obtained laminate had a narrow sealable temperature range and was inferior in hot tack property.

Comparative Example 5
(B) The resin composition of the layer was not blended with the ethylene-α-olefin copolymer (a), and the blending ratio was changed to 100 wt% of b-1 in the same manner as in Example 1, except that Pellets were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained resin composition of the (B) layer was inferior in high-speed spreadability, a laminated body could not be obtained, and was inferior in laminating property.

Comparative Example 6
(B) The blending ratio of the resin composition of the layer is A-1 60% by weight, b-1 25% by weight, high density polyethylene (C) (trade name Nipolon Hard 1000 manufactured by Tosoh Corporation, trade name Nipolon Hard 1000; density 966 kg / m ³ , MFR 20 g / 10 min) (hereinafter referred to as (c-1)) A pellet of the resin composition was obtained in the same manner as in Example 1 except that the content was changed to 15% by weight. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained laminate had a narrow sealable temperature range and was inferior in hot tack.

Comparative Example 7
Example 1 except that the ethylene-α-olefin copolymer (a) is not blended in the resin composition of the layer (B), and the blending ratio is changed to 40 wt% b-1 and 60 wt% c-1. Similarly, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained resin composition of the (B) layer had a large neck-in and was inferior in laminate processability. Moreover, the obtained laminated body had a narrow sealable temperature range and was inferior in hot tackiness.

Comparative Example 8
Example except that ethylene-α-olefin copolymer a-6 shown in polymerization example 5 was used instead of a-1 as the ethylene-α-olefin copolymer contained in the resin composition of layer (B). In the same manner as in No. 1, pellets of the resin composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 5.

  The obtained resin composition of the (B) layer was inferior in high-speed spreadability, and somewhat inferior in laminate workability at the time of forming a thin film.

Claims (7)

A laminate including at least a structure of (A) layer / base material layer / (B) layer, wherein (B) layer is an outermost layer, and (A) layer is composed of low-density polyethylene. , (B) layer density 945 kg / ^{m 3} or more 955 kg / ^{m 3} or less, JIS K6922-1 (hereinafter referred to as MFR) the melt flow rate measured by the method described in (1998) 10 g / 10 min or more 50 g / from more than 10 minutes of ethylene and C 3 obtained by copolymerizing 6 of α- olefins ethylene -α- olefin copolymer (a) 50 to 90 wt% and a density 915 kg / ^{m 3} or more 930 kg / ^{m 3} or less MFR 1 g / 10 min or more and 10 g / 10 min or less high pressure method low density polyethylene (b) 10 to 50 wt% (total of (a) and (b) is 100 wt%), and the following requirements (I) to ( II) Composed of the resin composition, the heat-foamable laminate for.
(I) Density 932 kg / m ³ or more and 953 kg / m ³ or less (II) MFR ³ g / 10 min or more and 43 g / 10 min or less The layered product used for heating and foaming according to claim 1, wherein the ethylene-α-olefin copolymer (a) of the layer (B) has a long chain branch. The layered product used for heating and foaming according to claim 1 or 2, wherein the ethylene-α-olefin copolymer (a) of the layer (B) satisfies the requirement (i).
(I) Long chain branches having 6 or more carbon atoms have 0.01 to 0.04 carbon atoms per 1000 carbon atoms The laminate used for heating and foaming according to any one of claims 1 to 3, wherein the ethylene-α-olefin copolymer (a) in the layer (B) satisfies the requirement (ii).
(Ii) The ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2 to 5 The ethylene-α-olefin copolymer (a) in the layer (B) is in the presence of a macromonomer satisfying the following requirements (iii) to (v) or simultaneously with the synthesis of the macromonomer, The laminate used for heating and foaming according to any one of claims 1 to 4, which is a polyethylene polymer obtained by arbitrarily polymerizing an olefin having 3 to 6 carbon atoms.
(Iii) obtained by polymerizing ethylene or copolymerizing ethylene and an olefin having 3 or more carbon atoms, and having a vinyl group at the terminal (iv) having a number average molecular weight (Mn) of 2000 or more (v) weight average molecular weight (Mw ) And the number average molecular weight ratio Mw / Mn is 2-5 The laminate for heating and foaming according to claim 1, wherein the method of laminating (A) layer / base material layer / (B) layer is an extrusion laminate molding method. A foam obtained by heating and foaming the laminate for heating and foaming according to claim 1.