JPH08244173A - Laminate - Google Patents

Abstract

PURPOSE: To manufacture a laminate for minimizing as far as possible bleeding matters from its sealant layer, preventing the change of taste for a content in a paper container formed by the laminate and making respective interlaminar bonding very firmly. CONSTITUTION: A gas burner layer is formed between a base paper and a sealant layer, and the value of contact angle measured by the aluminum foil contamination process for the sealant layer is 70 deg.C or under, and the value of carbon amount to aluminum is 0.80 or less in the laminate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate having a gas barrier layer provided between a base paper and a sealant layer.

[0002]

2. Description of the Related Art Conventionally, a laminate having a gas barrier layer provided between a base paper and a sealant layer constituting a laminate has been used, and in particular, when a paper container is molded by using the laminate, a sealant with which the contents contact is formed. The bleeding material from the layer was transferred to the contents, which was one of the causes for causing the off-taste or the change of taste especially when the contents were foods or beverages. Also,
The bleeding material from the sealant layer has a problem that it hinders the heat sealability of the sealant layer and reduces the adhesive strength between the sealant layer and the gas barrier layer. Furthermore, when a film in which a sealant layer and a gas barrier layer are combined is laminated on the base paper, the surface of the composite film that is bonded to the base paper is contaminated, and sufficient adhesive strength between the base paper and the composite film cannot be obtained. There was also.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is a laminate having a gas barrier layer between a base paper and a sealant layer constituting the laminate, and a paper container formed by the gas barrier layer. The purpose is to develop a laminate in which the bleeding material from the sealant layer with which the contents are in contact is reduced as much as possible so that the taste of the contents is not changed and the adhesion between the layers is strong.

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies on the above matters, and as a result, the present invention, namely, a laminate having a gas barrier layer provided between a base paper and a sealant layer, The above object is achieved by a laminate characterized in that the sealant layer has a contact angle value of 70 degrees or less measured by an aluminum foil contamination method and a carbon content value of 0.80 or less relative to aluminum. It has been found.

The present invention will be described in detail below.

The laminate of the present invention is a laminate in which a gas barrier layer is provided between a base paper and a sealant layer, and the sealant layer has a contact angle measured by an aluminum foil contamination method and a carbon amount against aluminum. Momo is a value in a specific range. In the present specification, the aluminum foil contamination method is to measure the amount of bleeding material from the sealant layer, and an aluminum foil having a contact angle of deionized water of less than 5 degrees is laid on the sealant layer to obtain 2 kg / m ² After heating at 40 ° C for 49 hours in the pressed state with the above weight, after leaving for 17 hours at 20 ° C and 60% RH, peel off the aluminum foil from the sealant layer, and contact the surface of the aluminum foil that was in contact with the sealant layer. The contact angle value is obtained by measuring the contact angle with deionized water by the droplet method, and the carbon amount value is obtained by ESCA from the peak area ratio of the carbon amount ratio to aluminum. This measurement may be performed with the sealant layer alone before the production of the laminate or after the production of the laminate. Hereinafter, the contact angle and the amount of carbon with respect to aluminum measured by the aluminum foil contamination method may be simply referred to as the contact angle and the amount of carbon, respectively.

The laminate of the present invention is used for various purposes as described later, but since it is particularly effective when used for a paper container, the laminate for a paper container will be mainly described below.

The sealant layer in the present invention is a layer which is provided on the outermost back surface of the laminate and is sealed when the laminate is molded into a paper container, and is a layer with which the contents of the paper container come into direct contact. For example, an unstretched film having a heat-sealing property of a polymer such as polyethylene, polyester, polyamide, and ethylene-vinyl alcohol copolymer can be used.

In the present invention, as the sealant layer of the laminate, one having a contact angle of 70 degrees or less and a carbon content of 0.80 or less with respect to aluminum is used. As a result, it has been found that a surprisingly excellent action effect is exhibited, and in the present invention, the sealant layer has a contact angle value of 7 or less.
It is necessary that it is 0 degrees or less, preferably 65 degrees or less, and the value of carbon amount is 0.80 or less, preferably 75 degrees or less.

When the value of the contact angle exceeds 70 degrees, the bleeding material from the sealant layer causes a taste change of the contents and inhibits the wettability of the sizing material for adhering the sealant layer and the gas barrier layer, which is sufficient. I can not get the adhesive strength,
The adhesive strength may decrease over time. When the amount of carbon exceeds 0.80 with respect to aluminum, the bleeding material from the sealant layer causes a taste change of the content, and when a film obtained by combining the sealant layer and the gas barrier layer is laminated on the base paper, The surface of the composite film that is laminated or laminated with the base paper is contaminated, and sufficient adhesive strength between the base paper and the composite film cannot be obtained, or the heat sealability of the sealant layer is impaired, and in either case, it is extremely undesirable.

Various film forming methods can be adopted for forming the sealant layer, but the value of the contact angle is 70.
It is desirable to form a film by an inflation method or a casting method in order to obtain a carbon amount of 0.80 or less.

The gas barrier layer in the present invention is a layer having an effect of preventing gas, particularly oxygen gas, from entering from the outside into the paper container, and having an effect of retaining moisture and flavor components from the paper container. , A plastic film, a vapor deposition film, a metal foil, or the like can be used.

The plastic film may be a uniaxially or biaxially stretched polymer such as polyester, polyamide, polycarbonate, polyvinylidene chloride, polyvinyl alcohol or ethylene-vinyl alcohol copolymer, or may not be stretched. The thickness thereof can be 6 to 60 μm.

The vapor-deposited film may be made of aluminum on one or both sides of the plastic film described above.
Silicon oxide, alumina, titanium oxide, etc. are vapor-deposited, and the thickness of the vapor-deposited layer is 200 nm or less, preferably 60 nm or less. Further, during the vapor deposition, the plastic film may be subjected to surface treatment such as corona treatment or application of an anchor coating agent to enhance the adhesiveness of the vapor deposition layer.

Further, as the metal foil, aluminum foil, iron foil,
Tin foil, copper foil, etc. can be used, and the thickness is 3 to
It is 50μ, preferably 5 to 15μ.

As the gas barrier layer, any one of a plastic film, a vapor deposition film and a metal foil may be used alone or in combination. Further, one or both surfaces of the gas barrier layer may be subjected to corona discharge treatment, anchor coating agent coating, resin coating, or the like.

In the present invention, the base paper constituting the laminate is one obtained by paper-making a natural fiber, a synthetic fiber or a mixture thereof, and has a thickness of 0.1 to 1.2 mm. And the gas barrier layer is laminated or laminated (hereinafter, the lamination or laminating may be simply referred to as laminating) with a printing or resin coat on the opposite surface. Good.

The base paper and the gas barrier layer and the gas barrier layer and the sealant layer are laminated, and there are various methods for laminating. First, in order to bond the base paper and the gas barrier layer, a dry laminating method, a wet laminating method, a sandwich laminating method or the like can be used. If necessary on both the base paper side and the gas barrier layer side, an anchor coating agent coating,
Corona treatment, ozone treatment, etc. may be applied and then laminated.
When laminating the gas barrier layer and the sealant layer, the laminating can be performed by the same method as described above, and the laminating of the gas barrier layers in the case of using the gas barrier layer in combination can also use the same method. .

Further, the sealant layer may be stuck to the one in which the base paper and the gas barrier layer are stuck, or the one in which the gas barrier layer and the sealant layer are stuck may be stuck to the base paper.

Further, a method of laminating a gas barrier layer and a sealant layer together with a sizing agent onto a base paper at once by a multi-layer co-extrusion laminating method, a multi-layer co-extrusion inflation film or a cast film including the gas barrier layer and the sealant layer, A method of laminating to the base paper by a dry laminating method, a wet laminating method, a sandwich laminating method or the like may be used.

It is preferable to further provide a resin layer having a heat-sealing property such as polyethylene on the raw paper surface of these laminates, which may be carried out before the raw paper and the gas barrier layer are pasted together, or after the pasting. You can go.

In order to make a paper container by using the thus obtained laminate, the laminate is creased or not, and is formed into a paper container through steps such as cutting, bending and sealing. The shape of the paper container can be cup type, gobel top type, flat top type, etc., but take a structure such that the end face of the base paper is not exposed inside the container by folding the skive or applying protective tape. Is desirable.

In the paper container obtained from the laminate of the present invention, the bleeding material from the sealant layer with which the contents come into contact can be reduced as much as possible so that the taste change of the contents does not occur, and the interlayer of each layer The bond becomes strong.

The laminate of the present invention is effectively used for paper containers, lid materials, pouch-shaped packaging materials, paper boxes and the like.

[0025]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. In the examples, a low-density polyethylene unstretched inflation film was used as a PE film, and an ethylene-methacrylic acid copolymer resin "Nucrel N-0908C" was used.
(Trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd., thickness 20 μ) may be referred to as EMAA.

Further, in the taste sensory test, 10 panelists scored 5 4, 3.2.1 points in order from the one with the least taste, and the total score was used as the taste score of the subject.
Therefore, the larger the total score, the smaller the change in taste.

Example 1 An aluminum foil (manufactured by Nippon Foil Co., Ltd., thickness: 7 μ) and a double-sided corona-treated polyester film “EF2002” (trade name, manufactured by Nimura Chemical Co., Ltd., thickness: 12 μ) were bonded by two-component curing. Agents "AD-590" and "CAT-55" (trade name, manufactured by Toyo Morton Co., Ltd., solid coating amount 3.5 g /
m ² ), a dry laminate is laminated, and a PE film (thickness: 60 μ) having a contact angle value of 36 degrees and a carbon amount value of 0.63 is formed on the polyester surface of the two-component curing adhesive. to obtain a composite film pasted dry lamination using the "AD-590" and "CAT-55" (solid content coating amount 3.5g / m ^2).

Further, the aluminum surface of this composite film and the base paper "Sake Pack Base Paper" (trade name, manufactured by Tokyo Paper Manufacturing Co., Ltd., weighing 400 g / m ² ) were laminated by sandwich sandwiching using EMAA. A low-density polyethylene "Petrocene 204" (trade name, manufactured by Tosoh Corporation, thickness: 20 µ) was extruded and laminated on the above to obtain a laminate. In order to evaluate the adhesion between the layers of the laminate obtained here, between EMAA / aluminum foil, polyester film / P
The results of measuring the adhesive strength between the E films are shown in Table 1.

This laminate was subjected to creasing, cutting, skiving, frame sealing, etc. to form a sleeve, and then a 1.8 liter gobel top paper container having a structure in which the cross section of the laminate was not exposed was filled with a filling molding machine. Sake 1.8
It was filled with liter and molded.

In order to evaluate the taste change of the contents of the obtained paper container, the sake in the paper container was filled with the sake 2 days after the filling.
The results of the taste sensory test by the comparative method are also shown in Table 1 together with those of the examples and comparative examples described below.

Example 2 A laminate was obtained in the same manner as in Example 1 except that a PE film (thickness 60 μ) having a contact angle value of 63 ° and a carbon amount value of 0.70 was used. It was

The results of measuring the adhesive strength of the obtained laminate in the same manner as in Example 1 are shown in Table 1.

The obtained laminate was filled and molded in the same manner as in Example 1 to obtain a paper container containing 1.8 liters of sake, and the sake in the paper container was subjected to the taste sensory test in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Examples 1 to 3 PE film (thickness 60 μ) having a contact angle value of 63 degrees and a carbon content value of 1.00 (Comparative Example 1), a contact angle value of 102 degrees and carbon Quantity value is 0.79
A PE film (thickness 60μ) (Comparative example 2) or a PE film (thickness 60μ) having a contact angle value of 103 degrees and a carbon amount value of 1.08 (Comparative example 3) is used. Was laminated in the same manner as in Example 1 to obtain a laminate. The results of measuring the adhesive strength of each of the obtained laminates in the same manner as in Example 1 are shown in Table 1.

The laminate was filled and molded in the same manner as in Example 1 to obtain a paper container containing 1.8 liters of sake, and the sake in the paper container was subjected to the taste sensory test in the same manner as in Example 1. The results are also shown in Table 1.

[0036]

[Table 1]

In Examples 1 and 2, the adhesive strength between the EMAA / aluminum foil and the polyester / PE film was high, the adhesiveness of each layer was good, and the change in taste was very small, and Comparative Example 1 2, the change in taste was smaller than that in Comparative Example 3, but it was larger than in Examples 1 and 2, and the adhesiveness of each layer was not sufficient.

On the other hand, in Comparative Example 3, the adhesion of each layer is insufficient and the change in taste is large.

Example 3 On the vapor-deposited surface of a silica single-side vapor-deposited polyester film "Tech Barrier U" (trade name, manufactured by Mitsubishi Chemical Corporation, thickness 12 µ), the contact angle was 36 degrees and the carbon content was 0. A PE film (thickness 60 μm) of 0.63 was laminated by dry lamination using two-component curing adhesives “AD-590” and “CAT-55” (solid content coating amount 3.5 g / m ² ). I got a film.

Further, on the polyester surface of this composite film, two-component curing type anchor coating agents "LX-63F" and "KP-90" (trade name, manufactured by Dainippon Ink and Chemicals, Inc., solid content coating amount 1.0 g) / M ² ), and using low density polyethylene “M-16P” (trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd., thickness 20 μ), base paper “cop base paper” (trade name, manufactured by Tokyo Paper Manufacturing Co., Ltd.) , Grammage 160g /
m ² ) and sandwich laminate, and the low-density polyethylene “PETROSEN 204” (thickness 20
μ) was extruded and laminated to obtain a laminate. Table 2 shows the results of measuring the adhesive strength between the M-16P / silica vapor-deposited polyester film and between the silica vapor-deposited polyester film / PE film in order to evaluate the interlayer adhesiveness of the obtained laminate.

After the laminate is creased, a 180 ml flat-top type paper container having a structure in which the cross section of the laminate is not exposed is formed with a mineral water 180 by a filling molding machine for sealing the roll paper in a sleeve shape.
It was filled with milliliter and molded. In order to evaluate the taste change of the contents of the obtained paper container, the mineral water in the paper container was filled with water, and two days later, Example 4 described below,
Simultaneously with those of Comparative Examples 4 to 6, the results of the taste sensory test performed in the same manner as in Example 1 are shown in Table 2.

Example 4 Ethylene-vinyl alcohol copolymer resin film "Eval XL" (trade name, manufactured by Kuraray Co., Ltd., thickness 12 µ)
On one side of the two-component curing type anchor coating agent "LX-63
F "and" KP-90 "(solids coating amount 1.0 g / m
² ) is applied and low-density polyethylene "Petrosene 20
4 ”(thickness 20 μm) was used to obtain a composite film by laminating a PE film (thickness 40 μm) having a contact angle value of 36 degrees and a carbon amount value of 0.63 with a sandwich laminate.

Further, this composite film EVAL XL
Two-component curing type anchor coating agents "LX-63F" and "KP-90" (trade name, manufactured by Dainippon Ink and Chemicals, Inc., solid content coating amount 1.0 g / m ² ) are applied to the surface, and the following operations are performed. A laminate was obtained in the same manner as in Example 3. Table 2 shows the results of measuring the adhesive strength between the M-16P / Eval XL and between the Eval XL / PE films in order to evaluate the interlayer adhesion of the laminate obtained here.

This laminated body was filled and molded in the same manner as in Example 3 to obtain a paper container containing 180 ml of mineral water. The results of a taste sensory test performed on the obtained mineral water in the paper container in the same manner as in Example 3 are shown in Table 2.

Comparative Examples 4 to 6 PE film (thickness 60 μ) having a contact angle value of 63 degrees and a carbon amount value of 1.00 (Comparative Example 4), a contact angle value of 102 degrees and carbon Quantity value is 0.7
A PE film (thickness 60 μ) of 9 (Comparative Example 5) or a PE film (thickness 60 μ) having a contact angle value of 103 degrees and a carbon amount value of 1.08 (Comparative Example 6) and the like are used. Except for this, the lamination was performed in the same manner as in Example 3 to obtain a laminate.

Table 2 shows the results of measuring the adhesive strength of each of the laminates obtained here in the same manner as in Example 3.

The laminated body thus obtained was filled and molded in the same manner as in Example 3 to obtain a paper container containing 180 ml of mineral water. The mineral water in the paper container was the same as in Example 3. The results of the taste sensory test are also shown in Table 2.

[0048]

[Table 2]

M-16P / silica-deposited polyester film in Example 3, silica-deposited polyester film / PE film, and M-1 in Example 3.
Both 6P / Eval XL and Eval XL / PE films have high adhesive strength, and the adhesiveness of each layer is good,
Taste changes are also very small.

On the other hand, in Comparative Examples 4 and 5, the change in taste was smaller than that in Comparative Example 6, but it was larger than in Examples 3 and 4, and the adhesiveness of each layer was not sufficient. Also,
In Comparative Example 6, the adhesiveness of each layer is insufficient and the change in taste is large.

Example 5 A three-kind five-layer co-extruded inflation film having a structure of A / B / C / D / E was prepared. However, A: low-density polyethylene (thickness 25 μ, contact angle: 42 degrees, carbon amount: 0.69) B: sizing agent “Admer NF550” (trade name, manufactured by Mitsui Petrochemical Co., Ltd., thickness 8 μ) C : Ethylene-vinyl alcohol copolymer resin "Eval E" (trade name, manufactured by Kuraray Co., Ltd., thickness 8 µ) D: Adhesive "Admer NF550" (thickness 8 µ) E: Low density polyethylene (thickness 10 µ) The low-density polyethylene (thickness 10 μ) surface of this co-push blown film was coated with the low-density polyethylene “M-16P” (thickness 20 μ) on the base paper “LIQ”.
UID PACKAGE BOARD "(trade name, EN
SO GUTZEIT OY, 300 g / m ² ) and a sandwich laminate were adhered, and low density polyethylene “PETROSEN 204” (thickness 20 μm) was extruded and laminated on the base paper surface to obtain a laminate.

In order to evaluate the adhesion between the layers of the laminate obtained here, between low density polyethylene (thickness 10 μ) / Eval E, Eval E / low density polyethylene (thickness 25
Table 3 shows the results of measuring the adhesive strength between μ).

The laminate thus obtained is subjected to creasing, cutting, skiving, frame sealing, etc. to form a sleeve, and then filled with a 1 liter govel top type paper container having a structure in which the cross section of the laminate does not appear. 1 liter of orange juice was filled with a molding machine and molded. In order to evaluate the taste change of the contents of the paper container obtained here, the results of a taste sensory test were conducted 2 days after filling with orange juice in the paper container in the same manner as in Example 1. Write according to 3.

Example 6 A / B / C / D / E (where A: low-density polyethylene (thickness: 25 μ)) was used with a three-kind five-layer co-laminating machine.
B, C, D and E are the same as those in Example 5), and the low density polyethylene (thickness 10 μm) side is used for the base paper “LIQUID PACKAGE BOARD” (30
0 g / m ² ) and coextrusion laminated. The contact angle of the surface of the low density polyethylene A measured here was 60 degrees, and the amount of carbon was 0.75.

Further, a low-density polyethylene "Petrosene 204" (thickness: 20μ) was extruded and laminated on the surface of the base paper to obtain a laminate. For the laminate obtained here,
The results of measuring the adhesive strength as in Example 5 are shown in Table 3.

This laminate was filled and molded in the same manner as in Example 5 to obtain a paper container containing 1 liter orange juice. The taste sensory test was performed on the obtained orange juice in the paper container in the same manner as in Example 5, and the results are shown in Table 3.

Comparative Examples 7 to 9 Low density polyethylene (thickness 25 μm) having a contact angle value of 60 degrees and a carbon content value of 1.18 as the A low density polyethylene in Example 5 (Comparative Example 7), Low-density polyethylene (thickness: 25 μ) having a contact angle value of 98 degrees and a carbon content value of 0.75 (Comparative Example 8) or a contact angle value of 103 degrees and a carbon content value of 1.08 A low-density polyethylene (thickness 25 μm) (Comparative Example 9) was used to carry out lamination in the same manner as in Example 5 to obtain a laminate.

Table 3 shows the results of measuring the adhesive strength of each of the laminates obtained here in the same manner as in Example 5.

This laminate was filled and molded in the same manner as in Example 5 to obtain a paper container containing 1 liter orange juice,
The results of the taste sensory test for each orange juice in the paper container are shown in Table 3 as in Example 5.

[0060]

[Table 3]

The low-density polyethylene (thickness 10 μ) / Eval E and the Eval E / low-density polyethylene (thickness 25 μ) in Examples 5 and 6 both had high adhesive strength,
The adhesiveness of each layer is good, and the change in taste is very small.

On the other hand, in Comparative Examples 7 to 9, the adhesiveness of each layer was sufficient, but the change in taste was large.

[0063]

EFFECTS OF THE INVENTION The laminate of the present invention can reduce the bleeding material from the sealant layer as much as possible, and prevent the taste change of the contents of the paper container obtained from the bleeding material. It will be very strong.

Claims (2)

[Claims] 1. A laminate having a gas barrier layer provided between a base paper and a sealant layer, wherein the sealant layer has a contact angle value of 70 degrees or less measured by an aluminum foil contamination method.
A laminate having a carbon content of 0.80 or less relative to aluminum. 2. The laminate according to claim 1, wherein the gas barrier layer is any one of a plastic film, a vapor deposition film and a metal foil, or a composite thereof.