JPH11300913A - Multi-layered film for heat seal, its manufacture, and paper container using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve low-temperature heat-sealing properties, slip characteristics, processability, sealing properties at the time of heat-sealing by containing at least one type of inorganic fine particles of specified amount in a heat sealant layer having specified composition/physical properties. SOLUTION: A multi-layered film 10 for HS is formed by sequentially co- extruding a heat sealant(HS) layer 1 composed of a low-density ethylene-αolefin copolymer (S-PE) which is polymerized by using a single-site catalyst having a melt index (MFR) of 0.2-20 g/10 min and a density of 0.890-0.925 g/cm<3> , an inner resin layer 2 composed of a thermoplastic resin, and a laminated layer 3 composed of a thermoplastic resin having a softening temperature higher than that of the HS layer 1. The HS layer 1 contains at least one type of inorganic fine particles having an average particle diameter of 5-20 μm 0.1-5 pts.wt. with respect to 100 pts.wt. blended resin, which is composed of 60-95 wt.% S-PE and 5-40 wt.% polyethylene having MFR of 0.2-20 g/10 min and a density of 0.926-0.965 g/cm<3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate (multilayer film for heat sealing, hereinafter multilayer film for HS) used as a component of a heat sealant layer (hereinafter, described as HS layer) of a container. The present invention relates to a multi-layer film for heat sealing which is excellent in processability of a film, moldability (sealing property) of a container, performance of retaining taste of contents, and a paper container technology using the same.

[0002]

2. Description of the Related Art It is needless to say that a paper container filled with a liquid, especially food, as a content must not have a liquid leakage or a vapor permeability from a sealed container (liquid sealing property). Furthermore, depending on the contents, the contents may be adversely affected by the permeation of oxygen in the air, such as deterioration or discoloration. Therefore, in order to preserve the contents for a long period of time, it is necessary that the above-mentioned paper container has not only water vapor but also gas containing oxygen (gas tightness).

FIG. 11 is a perspective view showing a part for checking the sealing property of the paper container 90. FIG.
FIG. 12B is a schematic enlarged view showing a portion of a cross section of the center seal portion CS in FIG. 11.
The liquid tightness and airtightness of the paper container 90 will be described with reference to the example of the goebel top type container shown in FIG. 11.
And a center seal portion CS at the center of the gobel. FIG.
As shown in FIG. 3A, a space X formed by the panels V2 and SV1 is provided in the cross section of the step portion DS. As shown in FIG. 12 (b), in the cross section of the center seal portion CS, gap portions Y are respectively formed at the junctions of the folded portions SV1 and SV2 of the side panels of the panels V1 and V2. In the step of forming the paper container, the resin on the inner surface of the paper container laminate must be melted to securely seal the gaps X and Y.

[0004] In order to ensure the sealing as described above, there is a method in which the heating and pressing conditions in the step of heating and melting the resin of the HS layer at the time of molding the container and pressing the resin together are strengthened. However, in such a case, the resin in the HS layer is removed, the resin in the heat-sealed portion is thinned, the adhesive strength is reduced (root breakage phenomenon), and breakage is likely to occur during distribution, which causes liquid leakage. . Also, if the heating conditions are increased,
In some cases, the HS layer in contact with the contents is oxidized, and low-molecular-weight decomposition products generated at that time are transferred to the contents and cause a deterioration in flavor. Under such contradictory heat sealing conditions, it is difficult to set the heat sealing conditions in the box making / filling / sealing process and to maintain a stable operation, it is difficult to avoid instability of the heat sealing, and the thickness of the HS layer is difficult. Had to be increased. Therefore, the structure of the laminate for obtaining a paper container having good heat sealability has been desired to have a wide range of working conditions, particularly a material that can stably heat seal even at a low sealing temperature.

On the other hand, low-density polyethylene (hereinafter, referred to as LDPE), which has been conventionally used for the HS layer of the above-mentioned gobel-top type paper container, is not only inferior in heat-sealing stability but also inferior in heat-sealing stability. In addition, when the contents adhere to the heat seal portion at the time of filling / sealing, there is a problem that a heat seal failure occurs.

The basic layer structure of a paper container used for filling a liquid of the above-mentioned goebel top type or brick type is as follows: "LDPE (surface resin layer) / paper (base material) / LD
PE (HS layer) ”. When strength or water vapor or gas barrier properties are required for the paper container, aluminum foil, a biaxially stretched polyethylene terephthalate film, a biaxially stretched nylon film, which is a film having a barrier property or strength between the paper and the HS layer. And a plastic film selected from aluminum-deposited plastic films and silicon oxide-deposited plastic films.

Further, it has a low-temperature heat-sealing property, a narrow molecular weight distribution, and a low-density polymerized by using a single-site catalyst having heat-sealing (seal with liquid) stability even when a liquid as a content is attached. It has also been attempted to use a film of the ethylene-α-olefin copolymer (hereinafter, referred to as S-PE). However, there is a problem that S-PE is inferior in film forming property and processing suitability of a paper container because of poor slip. In order to solve the slippage failure, the polyethylene resin composition constituting the HS layer was
There is known a method of improving slipperiness by adding 0.05 to 2.0 parts by weight of a crosslinked acrylic resin powder or a crosslinked silicone resin powder to 00 parts by weight (Japanese Patent Application Laid-Open No. Hei 7-1995). 179679). However, although these additives are effective for improving the slipperiness, they not only sediment on the heat seal surface during heat sealing and impair the heat sealability of the HS layer, but also hinder the seal with liquid. And it was difficult to obtain stable heat sealing properties. Further, in the manufacturing process of the paper container, the laminate is subjected to skive hemming (coating by folding the end face) at high speed, or frame sealing (cylinder sticking with hot air or a gas frame to form the container, or heat sealing of the top and bottom). Supplied to the machine. At that time, when the embossed film was used as the HS layer of the laminate on the innermost surface of the paper container, if the paper container blanks were stacked too much, the emboss was crushed and slippage became poor, or the ink container was formed with ink. There were inconveniences such as shaving off the surface of the blank picture layer. In addition, when pulling out the blanks from the stacked state and supplying them to the processing machine, when slippage is poor, a plurality of sheets are pulled out at once, or it is necessary to reduce the processing speed because traveling between processes is not performed smoothly. As a result, there were problems such as a decrease in production efficiency.

[0008] By embossing the film surface in a film forming step which is performed as a general method for improving the slipperiness of a film, the contact area can be reduced and slipperiness can be imparted. Equipment is required, and in order to provide an embossed shape that has an effect on slipperiness, it is necessary to reduce the processing speed, and as a result, there has been a problem that production efficiency is reduced.

Further, as a method for improving the slipperiness of a film, a method of mixing inorganic fine particles into a film, which is generally used, impedes the flow of the resin in the HS layer during heat sealing. Therefore, as shown in FIGS. 11 and 12 (a) and (b), there is a problem that a gap X and a gap Y formed in the cross section of the step portion DS are easily generated.

[0010]

As an inner layer film for a gobel-top type or brick type paper container, it has stable physical properties such as low-temperature heat-sealing properties and slipperiness, and can be formed into a film, laminated with a paper substrate, and a container. It is an object of the present invention to provide an inner layer film which is excellent in workability in each step of molding, particularly excellent in sealing property at the time of heat sealing of a container, and excellent in retention of physical properties of taste contents, and a laminate using the same. It is assumed that.

[0011]

In order to solve the above problems, the present invention provides at least a melt index (hereinafter referred to as MF).
Described as R. ) Of 0.2 to 20 g / 10 min and a density of 0.890 to 0.925 g / cm ^3, an HS layer made of S-PE, an intermediate resin layer made of thermoplastic resin, and HS
In a multilayer film formed by co-extrusion of a laminating layer made of a thermoplastic resin having a higher softening temperature than the layer,
The layer is composed of 60 to 95% by weight of the above S-PE,
0.2-20 g / 10 min, density 0.926-0.965
g / cm ³ of polyethylene and 5 to 40% by weight of a blend resin of 100 parts by weight, and at least one kind of inorganic fine particles having an average particle size of 5 to 20 μm is 0.1 to 0.1 parts by weight.
It is a multilayer film for heat sealing containing 5 parts by weight. The second invention is characterized in that the intermediate resin layer has at least 2
A softening temperature of the intermediate resin layer M in contact with the HS layer, which is higher than the softening temperature of the HS layer,
The MFR of the intermediate resin layer F in contact with the bonding layer side is 0.2 to 20.
g / 10 min and density 0.890-0.925 g / c
It is a multilayer film for heat sealing composed of m ³ S-PE. In a third aspect of the present invention, the thermoplastic resin forming the bonding layer has a MFR of 0.2 to 20 g / 10 min and a density of 0.925 to 0.965 g / cm ^{3 made} of polyethylene. It is a multilayer film for use. And
A fourth invention is a multilayer film for heat sealing, wherein the intermediate resin layer made of S-PE contains 0.1 to 3 parts by weight of inorganic fine particles having an average particle size of 5 to 20 μm. Further, the method is a method for producing a multilayer film for heat sealing in which the inorganic fine particles are blended as a master batch. Further, the bonding layer of the heat-sealing multilayer film and one side of the paper used as the base material are laminated with an adhesive resin layer or an adhesive therebetween, and a resin layer is formed on the other side. It is a paper container made of the laminated body provided. And it is the paper container which consists of a laminated body containing a water vapor and / or a gas barrier layer between the bonding layer of the said multilayer film for heat sealing, and the said paper base material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a multilayer film for HS of the present invention has an MFR of 0.2 to 20 g / 10 min and a density of 0.890 to 0.925 g / cm ³ S-PE.
Layer 10 made of a thermoplastic resin, an intermediate resin layer 2 made of a thermoplastic resin, and a bonding layer 3 made of a thermoplastic resin having a softening temperature higher than the softening temperature of the HS layer. However, the S-PE is 60 to 9
5% by weight, MFR 0.2-20 g / 10 min, density 0.
926 to 0.965 g / cm ³ of polyethylene
The heat-sealing multilayer film 10 includes 0.1 to 5 parts by weight of at least one kind of inorganic fine particles 21 having an average particle diameter of 5 to 20 μm with respect to 100 parts by weight of a blend resin composed of 0% by weight. .

As shown in FIG. 2, the intermediate resin layer 2 is composed of at least two layers and is in contact with the HS layer 1.
(26) The intermediate resin layer F made of a thermoplastic resin having a softening temperature higher than the softening temperature of the HS layer and in contact with the bonding layer 3 side.
(27) The heat-sealing multilayer film 10 made of S-PE having an MFR of 0.2 to 20 g / 10 min and a density of 0.890 to 0.925 g / cm ³ .

As shown in the figure, the thermoplastic resin forming the bonding layer has a MFR of 0.2 to 20 g / 10 minutes and a density of 0.925 to 0.965 g / cm ³ for heat sealing. It is a multilayer film 10.

As shown in FIG. 3, the average particle size is 5 to 20 μm.
S-PE containing 0.1 to 3 parts by weight of the inorganic fine particles 21
Is a multilayer film for heat sealing 10 having an intermediate resin layer B (25) made of:

A method for producing a multilayer film for heat sealing 10 in which the inorganic fine particles are blended as a master batch.

As shown in FIG. 7, the bonding layer 3 of the multilayer film 10 for heat sealing and the paper 6
The paper container 90 shown in FIG. 11 is formed from a paper container laminate 9 in which one side of the paper container is laminated with an adhesive resin 5 or an adhesive therebetween and a resin layer 8 is further provided on the other side. It is. In addition, as shown in FIG. 8, water vapor and / or water between the bonding layer of the multilayer film for heat sealing 10 and the paper base 6.
Alternatively, it is a paper container made of the laminate 9 including the gas barrier layer 7.

The laminated body for a paper container of the present invention, not only is produced by laminating a multilayer film on paper serving as a base material, but also by using the resin constituting the layer of the above-mentioned multilayer film for HS, and bonding the laminated layer. Can be formed by multi-layer coextrusion coating so as to contact one side of the paper used as the substrate.
As described above, the production method using multilayer coextrusion coating is a production method suitable for mass production.

The HS layer of the present invention is composed of S-PE and has no heat seal hindrance caused by contents.
Further, the multilayer film for the HS layer is formed by a step seal portion DS and a center seal portion CS of the paper container 90 shown in FIGS.
It is preferable to have physical properties to fill the gaps X and Y generated in the above. Therefore, the HS layer has a low melting point and an MFR
It is preferable that the material has a property of easily flowing when the heat seal is heated. In that sense, the MFR is 0.2
２０20 g / 10 min and a relatively low density of 0.890 to 0.925 g / cm ³ S- having a melting point of 90 ° C. to 120 ° C.
PE can form a preferred HS layer.

In the present invention, a problem associated with poor sliding may occur particularly when S-PE having a low density and a high MFR is used. In such a case, S-PE is set to 9
MFR compatible with S-PE for 5 to 60 parts by weight
Is 0.2 to 20 g / 10 min and the density is 0.926 to 0.2 g.
Medium to high density polyethylene of 965 g / cm ³
The problem can be solved by forming an HS layer in which 3.0 parts by weight of inorganic fine particles are blended with 100 parts by weight of a resin blend containing 0% by weight.

When the content of the above medium / high-density polyethylene is 5% by weight or less, the effect of improving poor slip is small, and when the content is 40% by weight or more, the heat sealing temperature rises. Not only can the portions X and Y not be sufficiently filled, but also the heat seal inhibiting effect due to contact with the contents, which is a characteristic of S-PE, is reduced.

The inorganic fine powder used for solving the above-mentioned problem associated with poor slip properties is prepared by adding 0.1 to 5 parts by weight of an inorganic filler having an average particle size of 5 to 20 μm by a master batch method. It is more preferable to form a film by uniformly dispersing the film. Since the inorganic filler does not melt even in the heated state,
Although effective in improving slippage, the thermal fluidity of the HS layer is impaired, and a gap is likely to be formed in the step seal portion and the center seal portion of the paper container. In order to prevent this drawback, the multilayer film for heat sealing of the present invention is obtained by adding a uniform and thin inorganic filler only to the portion where the HS layer is formed. This improves the surface slippage, maintains the thermal fluidity of the intermediate resin layer or the laminating layer, and prevents gaps generated in the step seal portion and the center seal portion of the paper container.

The inorganic filler used in the present invention is Si
O ₂ , Al ₂ O ₃ , TiO ₂ , ZnO, Fe ₂ O ₃ , S
nO ₂ , CeO ₂ , NiO, PbO, S ₂ Cl ₂ , Zn
Cl ₂ , FeCl ₂ , CaCO ₃ , MgCO ₃ , B ₂ O
_The average particle size can be selected from those having an average particle size of 5 to 20 μm from _{3 and the} like. And this inorganic filler is LDPE, S
-It can be uniformly dispersed in the HS layer or the intermediate resin layer B by using a masterbatch dispersed at a high concentration in PE for use. The content of the inorganic filler contained in the masterbatch is 2 to 20% by weight, depending on the density and type of the particles.
It is. Of course, the HS layer can be formed from a masterbatch blended with a medium / high density polyethylene containing inorganic fine particles and S-PE. In such a case, the blend of S-PE and high-density polyethylene can be omitted.

When the particle size of the inorganic filler is less than 5 μm, the effect of improving the slipperiness is small. Further, when the size exceeds 20 μm or when the amount of addition is too large, a heat seal failure occurs, or a layer inside the heat seal multilayer film during film formation, for example, an intermediate resin layer or a bonding layer,
Or it may damage the silicon oxide (Si0 _x) or aluminum deposition layer forming the barrier layer. Such a phenomenon is likely to occur when the softening temperature of the resin constituting the intermediate resin layer is close to that of the HS layer or when the MFR is relatively large (for example, 20.0 g / 10 min or more).

The use of two or more kinds of inorganic fine particles having different average particle diameters has a great effect on the improvement of slip. For example, by using a small amount of the filler having a small particle size with respect to the addition amount of the filler having a large particle size, an effect of improving processability including film forming aptitude was achieved. Further, the HS layer composed of the low-density S-PE is composed of 0.1 to 5% by weight of inorganic fine particles having an average particle size of 5 to 20 μm, and an average particle size of 5 to 20 μm having a smaller particle size than the inorganic fine particles. 4 to 6 containing 0.05 to 2% by weight of the inorganic fine particles are also preferable.

In the intermediate resin layer of the present invention, the inorganic fine particles are concentrated only on the surface of the multilayer film. The multilayer film as a whole has an effect of preventing a decrease in thermal fluidity due to excessive addition of inorganic fine particles. Then, even if the HS layer is melted at the temperature of heat sealing, the intermediate resin layer M and the bonding layer having a high softening temperature are
This prevents inorganic fine particles from entering the inside (HS layer) of the HS multilayer film from the surface (HS layer), thereby maintaining the surface slippage.

The intermediate resin layer M is selected from those which are higher than the softening temperature of the HS layer S-PE of 80 to 110 ° C., have excellent thermal fluidity, and adhere to the S-PE by coextrusion. For example, a medium / high density polyethylene having a density of 0.926 to 0.965 (softening temperature is 110 to 130 ° C., MFR
(0.2 to 20 g / 10 min) is preferred. In addition, it is a carrier for smoothly performing laminar flow during co-extrusion film formation, and it is preferable to select a material with emphasis on film formation suitability. For example, in the configuration shown in FIGS. 2 and 5, the intermediate resin layer M (26) at a temperature higher than the melting point of the HS layer causes the inorganic fine particles to flow into the low-density intermediate resin layer F (27) during heat sealing. This prevents the intermediate resin layer F (27) from flowing to the space as a whole in the multilayer film for heat sealing.

The intermediate resin layer F flows into the space at the time of heat sealing of the paper container to complete the sealing, has excellent heat fluidity, and is bonded to the intermediate resin layer M by coextrusion molding. I do. For example, there are the above-mentioned S-PE, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylate ester copolymer, and ionomer. In addition, it is preferable from the viewpoint of resource saving and recycling to appropriately mix and use scrap by-produced when producing the multilayer film of the present invention.

The bonding layer 3 can be selected from essentially the same material as the intermediate resin layer M. Preferably, a resin higher than the softening temperature of S-PE is preferable. Further, scrap produced as a by-product when producing the multilayer film of the present invention can be used by appropriately blending not only in the intermediate layer but also in the bonding layer.

The multilayer film for heat sealing of the present invention comprises:
The film can be formed with a T-type die or a circular die for producing an ordinary multilayer film.

The layer giving the water vapor and / or gas barrier properties to the paper container of the present invention, formed by depositing Si0 _x layer, metal aluminum on a plastic film was deposited a thermoplastic resin as the base material in stretched or unstretched And those coated with a layer of polyvinyl alcohol or vinylidene chloride. Also, there are saponified ethylene / vinyl acetate copolymer, acrylonitrile, polyvinyl alcohol, vinylidene chloride, nylon film and metal aluminum foil.

The lamination of the bonding layer of the multilayer film for heat sealing of the present invention and the above-mentioned barrier layer can be carried out by a usual method. For example, dry lamination using an adhesive (including non-solami laminating using an adhesive that does not contain a solvent at the time of coating) or sandwich lamination forming an adhesive resin layer by melt extrusion via a primer layer is appropriately selected. it can.

Although depending on the required degree of barrier property, the water vapor barrier of S-PE can be obtained by using nylon or saponified ethylene / vinyl acetate copolymer for the multilayer film intermediate resin layer M or F or the bonding layer. It is also possible to form a heat-sealing multilayer film having a synergistic effect with the properties. For example, S-PE (HS layer) containing inorganic fine particles / medium density polyethylene (intermediate resin layer M / ethylene / acrylic acid copolymer (intermediate resin layer F) / saponified ethylene / vinyl acetate copolymer (laminate layer) )) There is a constitution of a multilayer film for heat sealing.

The thickness of each layer of the multilayer film for heat sealing can be set arbitrarily. For example, the total thickness of the film is
30 to 100 μm, the ratio of each layer is HS layer / intermediate resin layer / laminated layer = 1/3/2 or HS layer / intermediate resin layer M / intermediate resin layer F / laminated layer = 2/2/5 / As shown in 4, the thinning of the HS layer containing the inorganic fine particles and the thickening of the intermediate resin layer F exert the effect of sliding by the inorganic fine particles and the effect of minimizing the flow inhibition, The intermediate resin layer F meets the purpose of filling the space in the heat seal portion of the paper container.

The base paper used in the laminate for a paper container of the present invention is a paperboard for a paper container which is uncoated or lightly coated (coated paper having a coating amount of 12 g / m ² or less). For example, ivory,
Select from card paper, general manila balls, etc. in consideration of rigidity, strength and thickness (basis weight g / m ² ). And preferably, a single layer papermaking or 150
It is those of ^{g / m 2 ~600g / m 2} .

The lamination of the heat-sealing multilayer film constituting the paper container laminate and the base paper is carried out by bonding the bonding layer of the heat-sealing multilayer film and the paper to an adhesive resin layer (usually LDPE). And lamination by sandwich lamination. When the bonding layer is made of a material other than polyethylene resin, such as a polyester film, a nylon film, or an aluminum foil, a primer layer is provided on the polyester film or aluminum to form an adhesive resin layer (LDP
Laminate using E). The thickness of the adhesive resin layer used for sandwich lamination for laminating the multilayer film for heat sealing and paper is 15 to 40 μm. The total thickness including the adhesive resin layer is not limited to the above numerical value, and can be arbitrarily set according to the size of the paper container.

When the side of the barrier layer is bonded to a resin having a carbonyl group such as nylon, saponified ethylene / vinyl acetate copolymer, or aluminum foil, the primer layer is not provided on the side of the barrier layer but directly HS by using an adhesive resin layer such as an acrylic acid copolymer, an ethylene / acrylate copolymer or an ionomer
The laminated body for a paper container can also be constructed by sandwich lamination with the bonding layer of the multilayer film for paper.

The lamination of the multi-layer film for heat sealing and the paper as the base material is not only performed by forming the laminated film in a separate process and laminating the paper, but also not shown in the drawing, the lamination layer and the paper are laminated. It can be constituted by coextrusion coating so as to be in contact with each other. For example, medium density polyethylene (laminated layer), low density S-PE
(Intermediate resin layer F), medium density polyethylene (intermediate resin layer M), and HS layer composed of S-PE, high density polyethylene and inorganic fine particles can be simultaneously co-extruded and coated. Further, an ethylene-acrylic acid copolymer (adhesive resin layer) composed of an acid polymer, a high-density polyethylene (lamination layer), a low-density S-PE ( An intermediate resin layer) and an HS layer composed of S-PE, medium-density polyethylene and inorganic fine particles can be simultaneously co-extruded and coated.

The laminated body for a paper container using the multilayer film for heat sealing of the present invention is used as the innermost film of the above-mentioned goebel top type or brick type paper container. The present invention can also be applied to containers containing liquid or viscous material, such as pouches, inner bags of bag-in-boxes, laminated tubes, paper cups, or round containers laminated with paper.

Hereinafter, the present invention will be described in more detail with reference to examples. Each of the films of the examples and the comparative examples was formed by a circular die.

[0041]

EXAMPLES Samples of Examples and Comparative Examples were prepared by using the following constitutions for a laminate for a paper container of a goebel top type. (Example 1) As shown in FIG.
S-PE having a melting point of 114 ° C. and 4.0 g of MFR was 70% by weight, a density of 0.958, a melting point of 132 ° C. and a MFR of 0.
10% by weight of 36 g of high-density polyethylene,
20% by weight of a master batch in which 15% of silica fine particles 21 having an average particle diameter of 7 μm are dispersed in PE [HS layer 1
1], containing 5% by weight of the master batch in the S-PE [intermediate resin layer B25], and having a density of 0.93.
5. Melting point 123 ° C., MFR 2.1 g [Laminating layer 3]
However, a multilayer film 10 for HS layer having a thickness of 40 μm and a layer ratio of 1: 3: 2 was prepared. Next, as shown in FIG.
And bonding layer 3 of 0, as a barrier layer, the thickness 1 deposited Si0 _x layer having a primer layer 32 of the isocyanate
2 μm polyester film 71 and 20 μm LD
PE was subjected to sandwich lamination using the adhesive resin layer 51. Furthermore, on the side of the polyester film,
A primer layer 33 is provided, and LDPE having a thickness of 30 μm is used as an adhesive resin layer 52, and one side of paper 6 serving as a base material having a basis weight of 400 g / m ² is sandwiched and laminated on another side of the paper to have a thickness of 20 μm. Example 1 of the present invention in which the resin layer 8 made of LDPE is formed by extrusion coating.
To form a laminate 9 for a paper container.

Example 2 As shown in FIG. 2, the [HS layer 1] used in Example 1 was made of medium density polyethylene having a density of 0.935, a melting point of 123 ° C., and an MFR of 2.1 g [intermediate. A resin layer M (26)], a two-layer intermediate resin layer 2 composed of S-PE [intermediate resin layer F (27)] having a density of 0.913, a melting point of 114 ° C., and an MFR of 4.0 g; The multilayer film for HS of Example 2 having a thickness of 40 μm and a composition ratio of 0.935, a melting point of 123 ° C., and an MFR of 2.0 [laminating layer 3], each having a layer ratio of 2: 2: 5: 4. 10 was created. Then, as in Example 1,
Si0 _x layer deposited polyester film 71 to prepare a laminate 9 for paper container according to Example 2 of the present invention to provide a sheet 6 and a resin layer 8 as a base material.

Example 3 As shown in FIG. 6, SP having a density of 0.913, a melting point of 114 ° C., and an MFR of 4.0 g was used.
E70% by weight, density 0.958, melting point 132 ° C,
0.36 g of MFR and 10% by weight of high density polyethylene;
10% by weight of a master batch in which 15% of silica 21 having an average particle diameter of 7 μm is dispersed in the S-PE and 5% by weight of a master batch in which 15% of silica 22 having an average particle diameter of 5 μm is dispersed in the S-PE. [HS layer 1]
A master batch in which the above-mentioned silica 22 having an average particle diameter of 7 μm is dispersed in PE at 5% by weight [intermediate resin layer B (2
5)], a density of 0.935, a melting point of 123 ° C., and an MF
R2g consisting of medium density polyethylene [Laminating layer 3]
Were prepared so as to have a layer ratio of 1: 3: 2, respectively, to produce a multilayer film 10 for HS of Example 3 having a thickness of 40 μm. Then, in the same manner as in Example 1, Si0 _x layer deposited polyester film 71 to prepare a laminate 9 for paper container according to Example 3 of the present invention to provide a sheet 6 and a resin layer 8 as a base material.

Example 4 As shown in FIG. 4, the [HS layer 11] used in Example 3 is composed of S-PE having a density of 0.913, a melting point of 114 ° C., and an MFR of 4.0 g [intermediate. Resin layer 2] and [Laminate layer 3] made of medium density polyethylene used in Example 2 were formed so that the layer ratio was 1: 3: 2, respectively. Film 10 was made. Then, in the same manner as in Example 1, Si0 _x layer deposited polyester film 71 to prepare a laminate 9 for paper container according to Example 5 of the present invention to provide a sheet 6 and a resin layer 8 as a base material.

Example 5 As shown in FIG. 5, a SP having a density of 0.913, a melting point of 114 ° C., and an MFR of 2.0 g was used.
E70% by weight, density 0.958, melting point 132 ° C,
0.36 g of MFR and 10% by weight of high density polyethylene;
From 15% by weight of a masterbatch in which 15% of silica 21 having an average particle diameter of 7 μm is dispersed in the S-PE and 5% by weight of a masterbatch in which 10% of silica 22 having an average particle diameter of 5 μm is dispersed in the S-PE. [HS layer 1], a medium density polyethylene having a density of 0.935, a melting point of 123 ° C. and an MFR of 2.0 g [intermediate resin layer M (26)], and S-PE used in Example 4 [ Intermediate resin layer F (27)
And an intermediate resin layer 2 composed of: and a [laminating layer 3] composed of the medium-density polyethylene used in Example 4, each having a layer ratio of 2: 2: 5: 4 and a thickness of 40 μm. 5 was prepared. Then, in the same manner as in Example 1, Si0 _x layer deposited polyester film 7 to prepare a laminate 9 for paper container according to Example 5 of the present invention to provide a sheet 6 and a resin layer 8 as a base material.

[0046] (Example 6) Si0 _x layer deposited polyester film 71 of the paper container stack 9 prepared in Example 1
Was replaced with aluminum vapor-deposited polyester, and a laminate 9 for a paper container of Example 6 was formed in the same manner as in Example 1.

[0047] (Example 7) Si0 _x layer deposited polyester film 71 of the paper container stack 9 prepared in Example 2
Was replaced with aluminum-evaporated polyester, and a laminate 9 for a paper container of Example 7 was formed in the same manner as in Example 2.

[0048] (Example 8) Si0 _x layer deposited polyester film 71 of the paper container stack 9 prepared in Example 3
The laminated body 9 for a paper container of Example 8 was formed in the same manner as in Example 3 except that was replaced with aluminum-evaporated polyester.

[0049] (Example 9) Si0 _x layer deposited polyester film 71 of the paper container stack 9 prepared in Example 4
Was replaced with aluminum-evaporated polyester, and a laminate 9 for a paper container of Example 9 was formed in the same manner as in Example 4.

[0050] (Example 10) Si0 _x layer deposited polyester film 7 of a paper container stack 9 prepared in Example 5
A laminate 9 for a paper container of Example 10 was formed in the same manner as in Example 5 except that 1 was changed to aluminum-deposited polyester.

Example 11 As shown in FIG. 10, an aluminum foil 72 having a thickness of 7 μm and a polyester film 73 having a thickness of 12 μm were laminated by dry lamination using a polyester-isocyanate adhesive 31. Next, an isocyanate-based primer layer 32 is provided on the polyester film, and a 20 μm thick L
Using the DPE 51, the lamination layer 3 of the multilayer film for HS 10 prepared in Example 1 was subjected to sandwich lamination. Next, using an ethylene / methacrylic acid copolymer having a thickness of 30 μm, the aluminum foil and the paper serving as the base material are sandwich-laminated with one side of the paper 6 serving as the base material having a basis weight of 400 g / m ² , Thickness 2 on the other side of the paper
A resin layer 8 made of 0 μm LDPE was formed, and a laminate 9 for a paper container of Example 11 of the present invention was formed.

(Example 12) HS used in Example 11
A laminate 9 for a paper container of Example 11 of the present invention was formed in the same manner as in Example 11 except that the multilayer film 10 for use was changed to that prepared in Example 2.

(Example 13) HS used in Example 11
A laminate 9 for a paper container of Example 13 of the present invention was formed in the same manner as in Example 11 except that the multilayer film 10 for use was changed to that prepared in Example 3.

(Example 14) HS used in Example 11
A laminate 9 for a paper container of Example 14 of the present invention was formed in the same manner as in Example 11 except that the multilayer film 10 for use was changed to that prepared in Example 4.

(Example 15) HS used in Example 11
A laminate 9 for a paper container of Example 15 of the present invention was formed in the same manner as in Example 11, except that the multilayer film for use was changed to that prepared in Example 5.

Comparative Example 1 The multilayer film for HS used in Example 1 was converted into a single-layer S-PE layer having a density of 0.913 g / cm ³ , an MFR of 4.0 g / 10 min, and a melting point of 114 ° C. Except having changed, the laminated body of the comparative example 1 was comprised like Example 1.

Comparative Example 2 A laminate 9 of Comparative Example 2 was constructed in the same manner as in Example 1 except that the HS multilayer film used in Example 6 was replaced with S-PE of Comparative Example 1.

Comparative Example 3 A laminate 9 of Comparative Example 2 was constructed in the same manner as in Example 1 except that the HS multilayer film used in Example 11 was replaced with S-PE of Comparative Example 1.

Comparative Example 4 The multilayer film for HS used in Example 1 was replaced with a single-layer LDPE layer having a density of 0.923 g / cm ³ , an MFR of 4.5 g / 10 min, and a melting point of 111 ° C. Except for the above, the same procedure as in Example 1 was repeated, except that the laminate 9 of Comparative Example 4 was used.
Was configured.

Comparative Example 5 A laminate 9 of Comparative Example 5 was constructed in the same manner as in Example 6, except that the multilayer film for HS used in Example 6 was replaced with the single-layer LDPE layer of Comparative Example 4. .

Comparative Example 6 A laminate 9 of Comparative Example 6 was constructed in the same manner as in Example 11, except that the HS multilayer film used in Example 11 was replaced with the single-layer LDPE layer of Comparative Example 4.

(Comparative Example 7) The multilayer film for HS used in Example 1 was replaced with a single-layer medium-density polyethylene having a density of 0.935 g / cm ³ , an MFR of 2.0 g / 10 min, and a melting point of 123 ° C. A laminate 9 of Comparative Example 7 was formed in the same manner as in Example 1 except for the above.

Comparative Example 8 A laminate 91 of Comparative Example 8 was produced in the same manner as in Example 6 except that the multilayer film for HS used in Example 6 was replaced with a single-layer medium density polyethylene of Comparative Example 5.
Was configured.

Comparative Example 9 A laminate 9 of Comparative Example 9 was constructed in the same manner as in Example 11 except that the HS multilayer film used in Example 11 was replaced with the single-layer medium density polyethylene of Comparative Example 5. did.

Next, in the process of preparing a 1.8-liter gobel-top paper container using each of the paper container laminates of Examples and Comparative Examples, the processability of the paper container including slippage of the laminate was evaluated. And mineral water and sake using a liquid filling machine, and the following evaluations were performed.

(Sealability) The seal check solution made of an organic solvent colored with a dye is used to seal the stepped portion of the heat seal portion and the space portion (X or Y) of the center seal portion with a seal check solution made of a dye. It is visually evaluated according to the degree of seepage. (Workability) The skive hebbing step of the paper container laminate and the supply property (the presence or absence of supply failure due to slippage failure) in the frame sealer, and the presence or absence of scratches generated when the paper container is pulled out from the stacked blanks are visually evaluated. (Effect on taste) 15 minutes after filling mineral water at 80 ° C or sake at 65 ° C into a gobel top paper box.
After cooling with a shower at 0 ° C., the sample is allowed to stand at 20 ° C. for 1 month, and the taste is evaluated by a sensory test. (Evaluation criteria) ◎ Good ○ There is some problem, but there is no problem in practical use △ It can be used depending on use conditions and applications × It can be used only for extremely limited applications Unusable

The method of evaluating each physical property is as follows.
[Seal Property (Heat Seal Property)] The presence or absence of voids (X or Y shown in FIG. 12) generated in the step portion and the center seal portion of the gobel top is visually evaluated by the degree of liquid leakage or seepage with a seal check liquid.・ ◎: Sealing condition is very good ・ ○: No voids and pinholes ・ △: No voids are found immediately after filling, but voids are found 6 months later ・ ×: Immediately after filling Gaps and pinholes are observed

[0068]

[Table 1]

[0069]

According to the present invention, the HS layer on the inner surface of the paper container is laminated on a paper which is a multi-layer base material for HS comprising S-PE, an intermediate resin layer (intermediate resin layer M, intermediate resin layer F) and a bonding layer. The paper container made of the paper container laminate has a low-temperature heat-sealing property and is excellent in hermeticity without generation of a space at the time of filling and sealing. The medium / high-density polyethylene and at least one or more inorganic fine particles contained in the HS layer having the minimum thickness are effective in improving the lack of sealing due to poor surface slippage and stabilizing the filling process.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a multilayer film for HS of the present invention.

FIG. 2 is a schematic sectional view of a multilayer film for HS having another configuration of the present invention.

FIG. 3 is a schematic cross-sectional view of a chemical resistant laminated film having another configuration of the present invention.

FIG. 4 is a schematic sectional view of a chemical resistant laminated film of an example.

FIG. 5 is a schematic cross-sectional view of a chemical resistant laminated film of another example.

FIG. 6 is a schematic cross-sectional view of a chemical resistant laminated film of another embodiment.

FIG. 7 is a schematic sectional view showing an example of a laminate for a paper container.

FIG. 8 is a schematic cross-sectional view showing another example of a paper container laminate including a barrier layer.

FIG. 9 is a schematic sectional view showing an example of a paper container laminate including a barrier layer according to an example.

FIG. 10 is a schematic cross-sectional view showing another example of the paper container laminate including the barrier layer of the example.

FIG. 11 is a perspective view showing an example of the paper container of the present invention.

FIG. 12 is an enlarged cross-sectional view of a seal portion for explaining a space portion. (a) Enlarged view of step seal part (b) Cross-sectional enlarged view of center seal part

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 HS layer 2 Intermediate fat layer 3 Bonding layer 4 Filler 5 Adhesive resin layer 6 Paper 7 Barrier layer 8 Resin layer 9 Paper container laminate 10 HS multilayer film 21, 22 inorganic fine particles 25 Intermediate fat layer layer B 26 Intermediate fat layer M 27 Intermediate fat layer F 31 Adhesive layer 32, 33 Primer layer 51, 52 LDPE layer 5 Adhesive resin layer 6 Paper 71 Evaporated film 72 Aluminum foil 73 Polyester film 90 Paper container DS Step seal CS Center seal portion X Void portion formed in step seal portion Y Void portion formed in center seal portion V1 to V2 Paper container panel

Claims (7)

[Claims] At least a melt index of 0.1.
2 to 20 g / 10 min, and a density of 0.890 to 0.92
Heat-sealant layer composed of low-density ethylene / α-olefin copolymer polymerized using 5 g / cm ³ single-site catalyst, intermediate resin layer composed of thermoplastic resin, and thermoplastic resin higher than the softening temperature of heat sealant layer In a multilayer film formed by co-extrusion of a bonding layer consisting of: a heat sealant layer comprising 60 to 95% by weight of the low-density ethylene / α-olefin copolymer and a melt index of 0.2 to 20 g / 10 Min, density 0.92
A blend resin consisting of 6 to 0.965 g / cm ³ of 5 to 40% by weight of polyethylene is added to 100 parts by weight,
A multilayer film for heat sealing, comprising 0.1 to 5 parts by weight of at least one kind of inorganic fine particles having an average particle size of 5 to 20 µm. 2. The intermediate resin layer comprising at least two intermediate resin layers, wherein the intermediate resin layer M in contact with the heat sealant layer is made of a thermoplastic resin having a temperature higher than the softening temperature of the heat sealant layer, and is in contact with the bonding layer side. F has a melt index of 0.2 to 20 g / 10 min and a density of 0.890 to
^3. The heat-sealing multilayer film according to claim 1, which is a low-density ethylene / α-olefin copolymer polymerized by using a single-site catalyst of 0.925 g / cm ³ . 3. The thermoplastic resin forming said bonding layer is made of polyethylene having a melt index of 0.2 to 20 g / 10 min and a density of 0.925 to 0.965 g / cm ^3. The multilayer film for heat sealing according to claim 1 or 2, wherein 4. An intermediate resin layer comprising said low-density ethylene / α-olefin copolymer, comprising 0.1 to 3 parts by weight of inorganic fine particles having an average particle diameter of 5 to 20 μm. Item 4. The multilayer film for heat sealing according to items 1 to 3. 5. A method for producing a multilayer film for heat sealing, wherein the inorganic fine particles according to claim 1 are blended as a master batch. 6. A laminating layer of the multilayer film for heat sealing according to claim 1 and one side of paper used as a substrate facing each other via an adhesive resin layer or an adhesive. ,
A paper container comprising a laminate having a resin layer provided on the other side. 7. A laminate comprising a water vapor and / or gas barrier layer between the bonding layer of the multilayer film for heat sealing according to claim 1 and the paper substrate. Item 7. The paper container according to Item 6.