JP2712875B2 - Manufacturing method of material for liquid container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a material for a liquid container, and more particularly, to a method for producing a material for a liquid container which is mainly made of paper and does not contain a metal foil and has a high gas barrier property.

[0002]

2. Description of the Related Art Conventionally, a liquid container material mainly composed of paper is made of a paper base material made of a laminate of paper and polyethylene resin, and is provided with water resistance (waterproofness) on the side in contact with the contents and the material. It has a polyethylene resin layer (sealant layer) for imparting thermal adhesiveness to the surface, and a polyethylene terephthalate film for shape retention is used. Further, it prevents oxidation deterioration of the contents. Laminated aluminum foil of about 9 μm is widely used as a gas barrier layer.

[0003] In recent years, the polyethylene resin of the sealant layer has a property of adsorbing and sorbing aroma components of the contents, and the polyethylene resin releases a low-molecular substance, which is transferred to the contents. By doing so, it is considered that the taste of the contents is impaired, and there is no adsorption or sorption of the above-mentioned fragrance component, and there is no release of low-molecular substances, and non-adsorbent resin such as polyester resin is used on the inner surface. Layers used as layers have been proposed (for example, see JP-A-57-163).
654, JP-A-1-139336).

[0004] On the other hand, since the liquid container uses a plastic film, it is difficult to reuse it industrially after it is used. Therefore, the liquid container is generally incinerated. When aluminum foil is used as the gas barrier layer, there is a problem that incineration is difficult. For this reason, in some European countries, the use of liquid paper containers using metal foil is regulated. In addition, there is a problem due to the use of metal foil that microwave heating desired in some cases is not possible in relation to contents.

It has been proposed to use a resin film having excellent oxygen barrier properties, such as an ethylene-vinyl alcohol copolymer or polyvinylidene chloride, instead of using a metal foil as a gas barrier layer. Resin films have remarkably inferior oxygen barrier properties as compared with aluminum foil, and have high moisture permeability. It is difficult to obtain an oxygen barrier property and a moisture-proof property equivalent to those of a metal foil using this film, and the thickness (30 μm) of a practical level is difficult.
m) or less, sufficient oxygen barrier properties and moisture-proof properties cannot be obtained.

As a technique for satisfying gas barrier properties without using a metal foil, Japanese Utility Model Application Laid-Open No. 1-96879 has been proposed.
A gazette is known. Here, a technique is disclosed in which a microwave-permeable sheet mainly composed of a plastic film provided with a silicon oxide thin film layer is used instead of a metal foil as a paper base material for a liquid container. According to this technique, sufficient oxygen barrier properties and moisture resistance can be obtained without using a metal foil.

The following is a comparison of oxygen barrier properties of aluminum foil, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and silicon oxide.

[0008]

[Table 1]

[0009]

In view of the above, if a thin film of a non-adsorbing resin and silicon oxide is used in a layer structure by combining the above techniques, the adsorption of the fragrance component by the sealant layer,
An excellent liquid container that solves the problems unique to metal foil can be obtained.

In the production of such a material for a liquid container, as a means for laminating a paper substrate or a plastic sheet and another plastic film, a plastic film is formed into a film in advance and laminated by an adhesive ( Dry laminating method), a method of laminating by applying heat to both (thermal laminating method), or melting a resin on a paper base or plastic sheet and extruding it into a film,
A method of laminating at the same time as film formation (extrusion laminating method) is known.

However, a thin film layer of an inorganic compound such as silicon oxide generally has poor flexibility. When the base sheet expands or contracts due to heat, the thin film layer of the inorganic compound cannot follow the expansion and contraction, and cracks occur. It has been found that the inherent gas barrier properties are significantly reduced.

Therefore, when manufacturing a material for a liquid container having a thin film layer of the above-mentioned inorganic compound in the layer constitution, a method of applying heat to the substrate sheet on which the thin film layer of the inorganic compound is formed cannot be adopted as a laminating means. There was a problem.

[0013] For this reason, the dry lamination method must necessarily be adopted. However, lamination using only the dry lamination method is disadvantageous not only in cost because of using a large amount of adhesive, but also in disadvantageous cost. Since the film to be laminated is produced by the inflation method, the film surface is smooth, and the workability is inferior due to blocking during the winding operation during the production process. Since the surface of the liquid container blank sheet is also smooth, the blank sheets are blocked from each other, and there is a disadvantage that automatic supply to the assembling work in a box shape is not performed stably.

Therefore, the present invention overcomes the problems of the dry laminating method which does not cause cracking of the inorganic compound when producing a liquid container material having a thin film layer of an inorganic compound in the layer structure. It is another object of the present invention to provide a material for a liquid container having excellent gas barrier properties.

[0015]

That is, the present invention provides a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin, a base sheet on which a thin film layer of an inorganic compound is formed, and a paper base. In producing a material for a liquid container, the step of co-extruding the co-extruded film and the co-extruded resin, at a temperature at which the thin film layer of the inorganic compound does not crack, and at a temperature at which the thermal adhesion is not lost And cooling the co-extruded resin onto the base sheet on which the thin film layer of the inorganic compound is formed,
Production of a material for a liquid container, characterized in that a sheet having a constitution of a non-adsorptive resin / first heat-adhesive resin / inorganic compound-coated substrate sheet is prepared, and then the sheet and a paper substrate are laminated. Is the way.

Further, a material for a liquid container comprising a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin, a base sheet on which a thin film layer of an inorganic compound is formed, and a paper base material is manufactured. In doing so, a step of co-extruding the co-extruded film, a step of cooling the co-extruded resin to a temperature at which the thin film layer of the inorganic compound does not break, and a temperature at which the thermal adhesion is not lost, Laminating the co-extruded resin on the base sheet on which the inorganic compound thin film layer is formed, and further, melting and extruding the second heat-adhesive resin at a temperature at which the inorganic compound thin film layer is not cracked, and Cooling to a temperature not losing thermal adhesiveness and laminating on a substrate sheet on the side opposite to the side on which the co-extruded film is laminated, whereby a non-adsorbent resin / first thermal adhesive resin / inorganic compound is obtained. Coating Create a sheet body sheet / second thermal adhesive resin constituting, then, characterized by laminating the said sheet and the paper substrate, a manufacturing method of the material for the liquid container.

Further, a material for a liquid container comprising a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin, a base sheet on which a thin film layer of an inorganic compound is formed, and a paper base material is manufactured. In doing so, a step of co-extruding the co-extruded film, a step of cooling the co-extruded resin to a temperature at which the thin film layer of the inorganic compound does not break, and a temperature at which the thermal adhesion is not lost, Laminating the co-extruded resin on the base sheet on which the inorganic compound thin film layer is formed, and further melting and extruding the second heat-adhesive resin at a temperature at which the inorganic compound thin film layer is not cracked, and Cooling to a temperature not losing thermal adhesiveness and laminating on a substrate sheet on the side opposite to the side on which the co-extruded film is laminated, whereby a non-adsorbent resin / first thermal adhesive resin / inorganic compound is obtained. Suffered A sheet having a configuration of a base sheet / second heat-adhesive resin is prepared, and then a third heat-adhesive resin is sandwiched between the second heat-adhesive resin of the sheet and a paper substrate. And a method for producing a material for a liquid container, comprising laminating both.

[0018]

In the first aspect of the present invention, the base sheet on which the inorganic compound thin film layer is formed and the non-adsorptive resin layer are formed by cooling the first heat-adhesive resin which has been cooled to the limit showing the heat adhesion. Thus, the influence of heat on the thin film layer of the inorganic compound is prevented, and the occurrence of cracks in the thin film layer is prevented.

In the second invention of the present invention, the second heat-adhesive layer cooled to the limit of the heat-adhesive property is provided on the opposite side of the base sheet on which the non-adsorbent resin layer is laminated according to the first invention. Since the resin is laminated, the influence of heat on the thin film layer of the inorganic compound is prevented as in the above, and the occurrence of cracks in the thin film layer is prevented. Then, the second thermo-adhesive resin is further cooled after lamination, becomes a heat insulating layer, and makes it possible to use a lamination method to which heat is applied in bonding with the paper base material.

In a third aspect of the present invention, the second sheet of the second invention is provided with a second heat-adhesive resin laminated thereon.
By directly laminating the heat-adhesive resin and the paper base material with the melt-extruded resin interposed therebetween, there is no problem in the production only by the dry lamination method, and the material for a liquid container can be produced.

In the present invention, since the film to be laminated is formed by extrusion, the smoothness of the surface depends on the surface condition of the nip roll at the time of extrusion, and a matting process can be performed so as to have an appropriate sliding property.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a material for a liquid container according to the present invention, FIGS. 2 to 4 are explanatory views showing respective steps of a method for producing a material for a liquid container of the present invention, and FIGS. It is a top view showing an example of a blank sheet for manufacturing the liquid container concerning the present invention.

As shown in FIG. 1, the material for a liquid container according to the present invention comprises at least a paper substrate 1 and a thin film layer 2 of an inorganic compound.
2, the non-adsorbent resin 31 and the first
This is a laminate including a co-extruded film 3 with a heat-adhesive resin 32.

The paper base material 1 is necessary for forming a container shape on paper 11 such as bleached kraft paper having a basis weight of about 200 to 500 g / m ² , which is conventionally used for this kind of container material. A material comprising a sealing layer 12 made of a polyolefin resin for imparting a good sealing property can be used. The seal layer 12 can be formed by laminating a polyolefin resin having a thickness of about 17 to 25 μm on the paper 11 by an appropriate method.

The base sheet 2 is formed on a base film 21 made of a heat-resistant film such as polyethylene terephthalate, stretched nylon, stretched ethylene-vinyl alcohol copolymer or the like, and a gas barrier such as silicon oxide, magnesium oxide or the like. Inorganic Compound Thin Film Layer 22
Is formed by a method such as vacuum evaporation, plasma evaporation, sputtering, or ion plating.

The thickness of the base film 21 should be about 6 to 20 μm in consideration of the suitability for handling in the step of forming the inorganic compound thin film layer 22 and the subsequent processing steps. preferable.

The thickness of the inorganic compound thin film layer 22 is at least 500 °, preferably at least 600 °. If the thickness of the thin film layer 22 is less than 500 °, sufficient gas barrier properties may not be obtained. Also,
If the thickness is more than 2000 °, cracks in the thin film layer will be remarkably generated in a later step, and this is not practical.

The co-extruded film 3 is made of a non-adsorptive resin 3
1 and a first heat-adhesive resin 32.

As the non-adsorptive resin 31, a resin which does not substantially adsorb and absorb odor components of the contents is used.

In the above-mentioned Japanese Patent Application Laid-Open No. 57-163654, the physical properties defining these non-adsorbing resins 31 are as follows.
The solubility index is increased, and one having a solubility index of 9.0 or more is used.

Specifically, an acid-modified and / or glycol-modified polyester resin in which polyethylene terephthalate, polybutylene terephthalate, or an acid component or a glycol component constituting these polyester resins is appropriately changed, and if necessary, Polyester resins, such as copolyesters, to which other third components have been added can be used.

Examples of the other non-adsorptive resin 31 include ethylene-vinyl alcohol copolymer, polyacrylonitrile and the like. These copolymers or blended resins, and blended resins of these with other resins Also,
It can be used in a range that satisfies the non-adsorption property of the present invention.

The non-adsorptive resin 31 is always formed on the side in contact with the contents of the liquid container in the present invention. For this reason, it is preferable that the non-adsorptive resin 31 has heat sealing properties in order to manufacture a liquid container from a liquid container material. For polyester resin,
By performing the above-mentioned acid modification and / or glycol modification, heat sealability can be obtained.

The non-adsorptive resin 31 is usually poor in extrusion suitability, and it is difficult to extrude alone and form a film. Therefore, a film can be formed by co-extrusion with another resin having excellent extrusion suitability. In the present invention, the first heat-adhesive resin 32 is used as a carrier.

As the first thermo-adhesive resin, a resin having thermo-adhesive properties such as low density polyethylene can be used.

Here, as the first heat-adhesive resin 32, the melt flow ratio (M
It is preferable to use a resin having a small FR). That is, by using a resin having a small MFR, neck-in of the non-adsorbent resin 31 during co-extrusion of the non-adsorbent resin 31 and the first heat-adhesive resin 32 can be suppressed to be small, and a uniform film can be formed. Can be easily processed, the flexibility of the film can be obtained, and the film can be formed favorably at low cost.

In co-extrusion of the non-adsorptive resin 31 and the first heat-adhesive resin 32, an adhesive resin 33 can be interposed if necessary.

The heat-adhesive resin 33 is made of the non-adsorptive resin 3
A resin having adhesive properties is used for both the first and first thermal adhesive resins 32. For example, when a polyester-based resin is used as the non-adsorptive resin 31 and low-density polyethylene is used as the first heat-adhesive resin 32, a modified polyolefin resin can be used as the adhesive resin 33.

According to the present invention, after extruding the above co-extruded film, it is cooled to an appropriate temperature, and on the base sheet 2 on which the inorganic compound thin film layer 22 has been formed, the thermal adhesiveness of the co-extruded film is utilized. To be laminated and integrated.

That is, as shown in FIG. 2, the non-adsorptive resin 31 and the first heat-adhesive resin 32
Is cooled by a cooling means such as a chill roll 71 to a temperature at which the thin film layer 22 of the inorganic compound is not broken, and to a temperature at which the thermal adhesiveness is not lost. They are pressed and laminated. Here, if necessary, the surface of the first heat-adhesive resin 32 of the co-extruded film 3 may be subjected to a treatment for improving the adhesion to the base sheet 2, for example, a corona discharge treatment. The corona discharge treatment uses a well-known corona discharge treatment device 8 and may be the same treatment as that in the related art. If necessary, an adhesive anchor coat layer (not shown) may be formed on the laminated surface of the base sheet 2.

The upper limit of the cooling temperature of the co-extruded resin is different depending on the material and thickness of the base film 21, the kind of the inorganic compound and the thickness of the thin film layer 22, and the lower limit is the first heat. Although it depends on the material of the adhesive resin 32, the temperature is preferably in the range of 20 to 50 ° C.

If the temperature is higher than 90 ° C., cracks are likely to occur in the inorganic compound thin film layer 22, while
If the temperature is lower than 15 ° C., the adhesive strength between the first heat-adhesive resin 32 and the base sheet 2 becomes insufficient, and the first heat-adhesive resin 32 is easily peeled off and cannot be used as a packaging material.

The laminating position of the co-extruded film 3 is set at the thin film layer 22 side of the base sheet 2 and the base film 2.
Either one side may be used.

The obtained sheet can be laminated with the paper substrate 1 by a method that does not apply heat, such as a dry lamination method.

Here, the second invention of the present invention relates to a method in which the second extruded thermo-adhesive resin 4 is melted and extruded on the side of the base sheet 2 opposite to the side on which the co-extruded film 3 is laminated. The structure is cooled to a temperature at which the thin film layer 22 does not break and does not lose the thermal adhesiveness, and the composition of the non-adsorbent resin / first thermal adhesive resin / inorganic compound-coated base sheet / second thermal adhesive resin Is created.

That is, as described above, laminating the sheet composed of the base sheet 2 and the co-extruded film 3 and the paper substrate 1 by the dry lamination method has the problems of slipperiness and cost as described above. It still exists. Therefore, it is desirable that the second thermo-adhesive resin 4 be cooled to a predetermined temperature and directly laminated on the base sheet 2.

In the method of laminating the second thermo-adhesive resin 4, the second thermo-adhesive resin 4 is melted and extruded from the extrusion die 62 in the same manner as the above-described lamination of the co-extruded film 3, and this is extruded by a chill roll 72. The cooling means cools the inorganic compound thin film layer 22 to a temperature at which the thin film layer 22 is not broken and does not lose the thermal adhesive property. Then, the base sheet 2 is overlaid on the side opposite to the side on which the co-extruded film 3 is laminated. Then, they are laminated by crimping (see FIG. 3). Also, if necessary,
As described above, the corona discharge treatment and the adhesive anchor coat layer can be applied.

As the second thermo-adhesive resin 4, a resin similar to the first thermo-adhesive resin 32 described above can be used.

As described above, in the sheet on which the second heat-adhesive resin 4 is laminated, the second heat-adhesive resin 4 functions as a heat insulating layer, so that extreme heat is no longer applied to the base sheet 2. Absent. Therefore, a known laminating means using heat can be applied to the above-mentioned bonding between the sheet and the paper substrate 1.

In order for the second thermo-adhesive resin 4 to sufficiently function as a heat insulating layer, the second thermo-adhesive resin 4
Is preferably 15 μm or more.

The order of laminating the co-extruded film 3 and the second thermo-adhesive resin 4 on the base sheet 2 is not particularly limited.

The lamination of the sheet on which the second thermo-adhesive resin 4 is laminated and the paper substrate 1 may utilize heat as described above, and the non-adsorptive resin 31 / first The third extruded third heat-adhesive resin 5 is sandwiched between the paper substrate 1 and the sheet having the constitution of the second heat-adhesive resin 32 / inorganic compound-coated base sheet 2 / second second heat-adhesive resin 4. Then, they can be laminated by press bonding (see FIG. 4).

The third thermo-adhesive resin 5 is not particularly limited as long as it has an adhesive property to both the second thermo-adhesive resin 4 and the paper substrate 1. It is preferable to use the same resin because the adhesiveness can be improved.
It is sufficient that the thickness of the third thermo-adhesive resin 5 is 10 μm.

It is to be noted that a thermal adhesive resin such as polyethylene is provided on the side of the paper substrate 1 which is in contact with the second thermal adhesive resin 4, and the second thermal adhesive resin 4 and the thermal adhesive resin are combined. A so-called thermal lamination method of heating and laminating is also conceivable, but heat cannot be applied from the base sheet 2 side (a large amount of heat is applied to the base sheet 2 and cracks occur in the thin film layer). Will be put on paper 1
Because of the high thermal insulation of (1), the thermal efficiency is extremely poor, and this method is difficult to adopt.

The material for a liquid container of the present invention obtained as described above is punched into a blank 9 having a shape as shown in FIGS. 5 and 6, for example, and is a rectangular container having a roof-type top or a block. It can be assembled into a container in a shape. Further, it is also possible to form the obtained material into a cylindrical shape by forming the obtained material into a cylindrical shape and attaching appropriate lid members to the upper and lower openings.

The obtained container can be filled with various beverages as in the past, but the liquid container according to the present invention is particularly suitable for juices, sakes, spirits and teas, which need to value the aroma of the contents. When used for filling contents such as coffee, other soft drinks, or bath agents, the effect is remarkable.

An embodiment of the present invention will be described below.

A bleached kraft paper having a basis weight of 320 g / m ² (trade name: SIE, manufactured by Shin-Fuji Paper Co., Ltd.) has a thickness of 20 μm on one side.
m of polyethylene film was laminated to prepare a paper substrate.

Separately, silicon oxide is provided as a thin film layer of an inorganic compound on one side of a biaxially stretched polyethylene terephthalate film (manufactured by Teijin Ltd., trade name: NS) having a thickness of 12 μm to a thickness of 1500 mm. A base sheet was prepared.

Next, on the silicon oxide surface of the base sheet,
A polyethylene resin (trade name: M401PC, manufactured by Mitsui Petrochemical Industry Co., Ltd.) was extruded from an extrusion die to a thickness of 30 μm, cooled by a chill roll cooled to about 5 ° C., and subjected to corona discharge treatment (degree of treatment: 43 dyne wetness index). / Cm or more (according to JIS K6768))
They were pressed and laminated. At this time, the temperature of the extruded polyethylene resin was about 35 ° C. immediately before lamination.

Next, a polyester resin (manufactured by Mitsui Polychemical Dupont Co., Ltd., trade name: Sealer PT J-80)
2) An adhesive resin (manufactured by Mitsui Petrochemical Industry Co., Ltd., trade name Admar SE800) and a polyethylene resin (Mitsui Petrochemical Industry Co., Ltd., trade name M401PC) were extruded from a co-extrusion die and co-extruded. Resin (resin temperature:
About 280 ° C.), cooled with a chill roll cooled to about 5 ° C., and subjected to corona discharge treatment (treatment degree: wettability index 43 dyne /
cm or more (according to JIS K6768))
The sheet was laminated on the polyethylene terephthalate surface of the base sheet, pressed and laminated to prepare a sheet having a structure of polyester resin / adhesive resin / polyethylene / polyethylene terephthalate / silicon oxide thin film layer / polyethylene.

Next, the polyethylene of the above-mentioned sheet and the paper of the paper base are faced to each other, and between them, a polyethylene resin having a thickness of 20 μm is extruded from an extrusion die. A container material was obtained.

When the oxygen permeability and the moisture permeability of the obtained liquid container material were measured, the oxygen permeability was 1 cc / m ² · 2.
4 hr · atm, moisture permeability 0.7 g / m ² · 24 hr ·
atm (40 ° C., 90% RH) and sufficient gas barrier properties.

For the purpose of comparison, the same extruded resin was not cooled but was prepared in the same manner as described above, and the gas barrier property was evaluated. The oxygen permeability was 5 cc / m ^2.
・ 24hr ・ atm, moisture permeability 3g / m ²・ 24hr ・
atm (40 ° C., 90% RH), and sufficient gas barrier properties could not be obtained. When this was decomposed and the state of the inorganic compound thin film layer was observed with a microscope, countless fine cracks were generated in the thin film layer.

Next, the material for a liquid container of the present invention and a material for a liquid container using a conventionally known polyethylene as an inner surface layer are punched into blanks 9 having the shape shown in FIG. 3 and assembled to produce a liquid container. After filling with orange juice as a content and storing it for 4 weeks at 25 ° C. and 65% RH, a sensory test was carried out. On the other hand, in the case where the conventional polyethylene was used for the inner surface layer, it was faintly felt that the smell of the polyethylene was transferred to the contents.

When the material for a liquid container of the present invention and the material for a liquid container using a conventionally known aluminum foil as a gas barrier layer were respectively incinerated, the material of the present invention was completely burned and toxic gas was removed. Although it did not occur, the conventional one using aluminum foil had aluminum foil remaining without burning, and it was clear that the present invention was advantageous.

[0068]

As described above, according to the present invention, the gas barrier property is excellent without causing cracks in the thin film layer of the inorganic compound, and the problem in the case of using a metal foil is solved. An excellent material for a liquid container capable of preserving the scent of the contents can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid container material according to the present invention.

FIG. 2 is an explanatory view showing a step of laminating a co-extruded film in the method for producing a material for a liquid container of the present invention.

FIG. 3 is an explanatory view showing a step of laminating a second thermo-adhesive resin in the method for producing a material for a liquid container of the present invention.

FIG. 4 shows a method for producing a material for a liquid container of the present invention.
It is explanatory drawing which shows the lamination process of a lamination sheet and a paper base material using the 3rd thermoadhesive resin.

FIG. 5 is a plan view showing an example of a blank sheet for manufacturing the liquid container according to the present invention.

FIG. 6 is a plan view showing another example of a blank sheet for manufacturing the liquid container according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paper base material 11 ... Paper 2 ... Base sheet 21 ... Base film 22 ... Thin film layer of inorganic compound 3 ... Co-extruded film 31 ... Non-adsorbent resin 32 ... First heat-adhesive resin 33 ... Adhesiveness Resin 4 Second thermal adhesive resin 5 Third thermal adhesive resin 61, 62, 63 Extrusion dies 71, 72 Chill roll 9 Blank sheet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // B29K 23:00 67:00 B29L 9:00 22:00

Claims (3)

(57) [Claims] 1. A liquid container material comprising a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin, a base sheet on which a thin film layer of an inorganic compound is formed, and a paper base. In doing so, a step of co-extruding the co-extruded film, a step of cooling the co-extruded resin to a temperature at which the thin film layer of the inorganic compound does not break, and a temperature at which the thermal adhesion is not lost, A step of laminating the co-extruded resin on the base sheet on which the inorganic compound thin film layer is formed, to prepare a sheet having a configuration of non-adsorbent resin / first heat-adhesive resin / inorganic compound-coated base sheet; Next, the sheet and a paper substrate are laminated,
A method for producing a material for a liquid container. 2. A material for a liquid container, comprising a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin, a base sheet on which a thin film layer of an inorganic compound is formed, and a paper base material. In doing so, a step of co-extruding the co-extruded film, a step of cooling the co-extruded resin to a temperature at which the thin film layer of the inorganic compound does not break, and a temperature at which the thermal adhesion is not lost, Laminating the co-extruded resin on the base sheet on which the inorganic compound thin film layer is formed, and further melting and extruding the second heat-adhesive resin at a temperature at which the inorganic compound thin film layer is not cracked, and Cooling to a temperature not losing thermal adhesiveness and laminating on a substrate sheet on the side opposite to the side on which the co-extruded film is laminated, whereby a non-adsorbent resin / first thermal adhesive resin / inorganic compound is obtained. Coated substrate DOO / second into a sheet having a heat-adhesive resin structure, then, the sheet and is characterized by laminating a paper substrate material production method for a liquid container. 3. A material for a liquid container, comprising: a co-extruded film of a non-adsorbent resin and a first heat-adhesive resin; a base sheet on which a thin film layer of an inorganic compound is formed; and a paper base. In doing so, a step of co-extruding the co-extruded film, a step of cooling the co-extruded resin to a temperature at which the thin film layer of the inorganic compound does not break, and a temperature at which the thermal adhesion is not lost, Laminating the co-extruded resin on the base sheet on which the inorganic compound thin film layer is formed, and further melting and extruding the second heat-adhesive resin at a temperature at which the inorganic compound thin film layer is not cracked, and Cooling to a temperature not losing thermal adhesiveness and laminating on a substrate sheet on the side opposite to the side on which the co-extruded film is laminated, whereby a non-adsorbent resin / first thermal adhesive resin / inorganic compound is obtained. Coated substrate G / a sheet having the configuration of the second heat-adhesive resin is prepared, and then the third heat-adhesive resin is sandwiched between the second heat-adhesive resin of the sheet and the paper base, A method for producing a material for a liquid container, comprising laminating both.