JPH08244172A - Laminated film - Google Patents

Abstract

PURPOSE: To manufacture a laminated film useful as a packaging material of low permeability to water vapor and good toughness for a medicine, a pesticide, a fertilizer, a cleaning agent, resin of water absorption properties and the like by sticking temporarily a resin layer composed of biodegradable resin of specified tensile yield releasably on a water-soluble layer. CONSTITUTION: In a laminated film composed of a water-soluble resin layer A and a resin layer B stuck to the resin layer A temporarily and releasably, biodegradable resin is used for the resin layer B, and the tensile yield elongation of the resin layer B is 8% or more. Also preferably in the laminated film, the tensile yield strength of the resin layer B is 8 MPa or more, and the value formed by dividing the tensile destruction elongation value of the resin layer B by the tensile yield elongation value of the resin layer B is 3 or more. The tensile yield strength, tensile yield elongation and tensile yield destruction elongation referred above are measured in compliance with the method stipulated in JIS K-7127. Also the permeability to water vapor is measured at 25 deg.C at a relative humidity of 90% in compliance with the method stipulated in JIS Z-0208.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a laminated film. More specifically, it relates to a laminated film useful as a water-soluble packaging material.

[0002]

It is known to use a film made of a water-soluble polymer such as polyethylene oxide or polyvinyl alcohol as a water-soluble packaging material. Water-soluble packaging materials are used to package medicines, agricultural chemicals, fertilizers, detergents, water-absorbent resins, etc.
At the time of use, the bag is put into water to release the contents, which eliminates the need for weighing when using it, and causes fine powder generation, inhalation problems, and items to be packaged are directly contacted by workers such as agricultural chemicals. There is an advantage that the safety of work when handling a substance that is dangerous can be improved. It also has the effect of controlling the release rate of the contents by appropriately adjusting the dissolution rate of the packaging material.

However, the film made of the water-soluble resin as described above is (i) the film made of these resins has a very high moisture permeability and the contents easily absorb moisture. (Ii) Therefore, these films are Many of the packages used are double-packed in a protective bag with a high gas barrier property such as a bag laminated with aluminum foil during storage, and when used, the package inside is removed from the protective bag before use. However, there is a problem that a large protective bag remains as a waste after use.

Therefore, for the purpose of improving the storage and handling of the polyethylene oxide water-soluble film, a polyethylene oxide polymer layer and a thermoplastic resin layer which is difficult to adhere to the polyethylene oxide polymer are temporarily adhered to each other. A laminated film is disclosed in JP-A-6-3186.
No. 6 is proposed. If a laminated film obtained by using a resin having low moisture permeability for a layer of a thermoplastic resin that is difficult to adhere to a polyethylene oxide-based polymer based on the patent is used as a packaging material, the conventional double wrapping becomes unnecessary, and The problem of the protective bag remaining as a waste and the problem of moisture absorption of the contents during storage, which were problems with the water-soluble packaging material, are solved.

However, the thermoplastic resins that are difficult to adhere to the polyethylene oxide polymer used in the laminated film proposed in the above publications are non-decomposable or hardly decomposable resins, and these are In view of the fact that the above-mentioned resin remains as a waste and the treatment of these used (non-hard) decomposable plastic wastes has become a big social problem in recent years, the laminated film composition as disclosed in the above publication is considered. Is adopted as a packaging material,
It is not preferable because it may cause new waste problems.

On the other hand, JP-A-62-209144 proposes a laminate of a film of a hydroxybutyrate polymer composition having biodegradability and a water-soluble film. However, in the above publication, there is no description regarding the adhesiveness between the film of the hydroxybutyrate polymer composition and the water-soluble film, and the hydroxybutyrate polymer is generally brittle, so that the tensile yield elongation is higher than that of other thermoplastic resins. Is extremely small, and there is a problem in strength particularly when using packaging materials and the like.

[0007] Therefore, the problems that the conventional laminated film for the water-soluble packaging material has, that is, (i) waste generated during use and its disposal (ii) weak film strength are solved at the same time. The laminated film for water-soluble packaging materials has not existed so far.

[0008]

The present invention has been made to solve the above problems, and is useful as a packaging material for medicines, agricultural chemicals, fertilizers, detergents, water-absorbent resins, etc., and has low moisture permeability. Aiming to provide a tough laminated film,
Further, when used as a water-soluble packaging material, it is an object of the present invention to provide a laminated film in which a resin layer which becomes unnecessary when being put in an aqueous medium can be peeled off very easily and which does not cause a waste problem.

[0009]

Means for Solving the Problems As a result of intensive studies made by the present inventors, the present invention comprises a water-soluble resin layer (I) and a resin layer (II) which is detachably attached to the resin layer (I). It was found that the above-mentioned problems can be solved by using a biodegradable resin for the resin layer (II) in the laminated film and setting the value of the tensile yield elongation of the resin layer (II) within a specific range, and the present invention Has been completed.

That is, according to the present invention, the water-soluble resin layer (I) and the resin layer (I) detachably temporarily attached to the resin layer (I).
A laminated film comprising I), which comprises the resin layer (II)
Is made of a biodegradable resin, and the tensile yield elongation of the resin layer (II) is 8% or more.

The laminated film has the resin layer (I
The tensile yield strength of I) is 8 MPa or more, and the value of the tensile fracture elongation of the resin layer (II) is the resin layer (II).
It is preferable that the value obtained by dividing by the value of the tensile yield elongation of 3 is 3 or more.

The tensile yield strength, tensile yield elongation and tensile breaking elongation as referred to in the present invention are those measured according to the method described in JIS K-7127. Further, the water vapor transmission rate as referred to in the present invention refers to that measured at 25 ° C.-90% relative humidity according to the method described in JIS Z-0208.

[0013]

The laminated film of the present invention has a water-soluble resin layer (I).
By selecting a resin layer (I) that is difficult to adhere to, a peelable film such as a fusion strength (peeling strength) of 10 g / cm width (180 degrees) can be prepared without strictly adjusting the temperature during lamination. It is a film in a temporarily attached state of about (peeling). Normally, the layers are in close contact with each other and are not peeled off, but if a part of the film is peeled off to give a chance, it can be peeled off easily from there.

The resin used in the water-soluble resin layer (I) of the present invention is not particularly limited, and in addition to polyethylene oxide, polyvinyl alcohol, poly (ethylene-vinyl alcohol), pullulan, the range that does not impair the water solubility of these resins. Examples thereof include copolymers obtained by copolymerizing other components, and mixtures with other polymers. Among them, polyethylene oxide is easily removable from the resin layer (II) and is thermoplastic. It is preferable in that a laminated film can be produced by a coextrusion method. On the other hand, polyvinyl alcohol or poly (ethylene-vinyl alcohol) is a resin layer (I) depending on the type of biodegradable resin used and manufacturing conditions.
It may react with I), impair the water solubility of the film, and may be difficult to peel from the resin layer (II).

The biodegradable resin used in the resin layer (II) of the present invention is not particularly limited as long as it is a biodegradable resin.

Further, the biodegradable resin used in the resin layer (II) of the present invention acts as a protective layer when the laminated film of the present invention is used as a packaging material, and prevents moisture absorption of a packaged object. In addition to that, it must have sufficient mechanical properties as a protective layer. Specifically, the resin layer (II) has a length of 3 cm × width of 1 cm × thickness of 50 to 250 μm.
The tensile yield elongation of the resin layer (II) was 8% or more, preferably 10 when the tensile tester was held at a crosshead speed of 20 mm / min by holding a monolayer film of m as 1 cm at both ends meshing portions in a tensile tester. % Or more, more preferably 2
It is essential to be 0% or more. Resin having a small tensile yield elongation or rupture without reaching the yield point in the tensile test generally tends to be brittle, and particularly when the tensile yield elongation is smaller than the above range, the flexibility of the obtained film is extremely high. Since it is low, it is not practical and is not suitable as the resin layer (II) of the laminated film of the present invention. Further, it is preferable that the physical properties of the resin layer (II) simultaneously satisfy the requirements (1) and (2) described below.

(1) Tensile yield strength is 8 MPa or more, preferably 10 MPa or more. Tensile yield strength is 8 MPa
If it is less than the above range, the strength of the protective layer is insufficient, and thus plastic deformation such as stretching of the film may be easily caused by an extremely small external force.

(2) The value obtained by dividing the tensile breaking elongation by the tensile yield elongation is 3 or more, preferably 5 to 1000.
When this value is lower than the above range, the film may be immediately broken when an external force equal to or higher than the tensile yield strength is applied. Further, this value becomes infinite when the sample is fractured without reaching the yield point in the tensile test because the resin is very brittle, but this is unavoidable and It shows that it has very brittle properties, and it is obvious that it cannot be used as the resin layer (II) of the present invention. Furthermore, this value is 10
The resin layer (II) of more than 00 is generally very soft and may not have sufficient strength as a protective layer.

Examples of the biodegradable resin that provides a biodegradable resin layer that can satisfy the above requirements include poly (alkylene succinate) such as poly (ethylene succinate), poly (butylene succinate), and poly (ε). -Caprolactone), poly (3-hydroxypropionate), polylactic acid, polyglycolic acid, poly (lactic acid-glycolic acid),
Cellulose acetate, polyethylene-starch blend,
Examples thereof include poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-3-hydroxyvalerate), and one or more of these can be used. Among the above resins, poly (alkylene succinate), poly (ε-caprolactone), polyethylene-starch blend, poly (3-hydroxypropionate), and cellulose acetate are more excellent in water resistance than other biodegradable resins. In addition, poly (alkylene succinate), poly (ε-caprolactone), and polyethylene-starch blend are preferable in that the resin has low moisture permeability. By the way, among the biodegradable resins, poly (3
-Hydroxybutyrate) and poly (3-hydroxybutyrate-3-hydroxyvalerate) are biodegradable resins produced by microorganisms and are safer than other biodegradable resins synthesized by the chemical synthesis method. However, these resins are generally brittle, and their tensile yield elongation is extremely small as compared with other biodegradable resins. Therefore, caution is required when using these resins.

The resin layer (II) in the present invention may be subjected to a corona discharge treatment or a treatment with a surface treatment agent for the purpose of controlling the adhesion with the resin layer (I).

The laminated film of the present invention has a resin layer (I) which is removable from the surface of the film or the resin layer (I).
The interface between I) and the resin layer (I) may be subjected to aluminum vapor deposition treatment or gas barrier coating treatment with vinylidene chloride or the like.

The laminated film of the present invention is JIS Z-0.
The moisture permeability measured by the method described in 208 at 25 ° C.-90% relative humidity is preferably 250 g / m ² · 24 hours or less, more preferably 150 g / m ² · 2.
It is 4 hours or less, more preferably 100 g / m ² · 24 hours or less. Water vapor transmission rate of laminated film is 250g / m ²
・ If it exceeds 24 hours, a sufficient moisture-proof effect cannot be obtained. Also, when the hygroscopicity of the contents is very high, 150 g / m ² · 24 hours or less, preferably 100 g
/ M ² · 24 hours or less is desirable.

The method for molding the laminated film of the present invention is not particularly limited, and the resin layer (I) is formed on the resin layer (II).
And a method of forming the resin layer (I) and the resin layer (II) at the same time by extrusion using a multilayer molding machine having a plurality of extrusion ports. The apparatus used is also not particularly limited, and examples thereof include a heat press, an inflation apparatus, a T die apparatus, a calender apparatus and the like.

The thickness of the laminated film of the present invention is not particularly limited, but in order to obtain a flexible and tough laminated film, the total thickness of the resin layer (I) and the resin layer (II) is 3
The thickness of the resin layer (I) is preferably 0 μm to 300 μm, and the thickness of the resin layer (I) is preferably 10 μm to 250 μm. When the thickness of the resin layer (I) is less than 10 μm, the strength of the resin layer (I) is very weak and the resin layer (II)
The resin layer (I) may be damaged when the resin is peeled off. On the other hand, when the thickness of the resin layer (I) is larger than 250 μm, the dissolution time of the resin layer (I) may be remarkably long.

In the laminated film of the present invention, various stabilizers, nucleating agents, extenders and other additives may be mixed therein,
An adhesive layer or the like is interposed between the resin layer (I) and the resin layer (II) within a range that does not impair the water solubility of the resin layer (I) and the removability of the resin layer (I) and the resin layer (II). You may let me.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

<Measurement of Tensile Yield Strength, Tensile Yield Elongation and Tensile Fracture Elongation> The tensile yield strength, tensile yield elongation and tensile fracture elongation of the laminated film are measured according to JIS K-71.
It measured based on 27.

<Measurement of Moisture Permeability> The moisture permeability of the laminated film was measured at 25 ° C.-90% relative humidity according to the following JIS Z-0208.

<Example 1> 5 g of polybutylene succinate pellets were sandwiched between two 300 mm long × 300 mm wide × 5 mm thick mirror plates made of SUS304, and a 120-ton press manufactured by Miura Press Co., Ltd. was used. The pressure was maintained at a high side gauge pressure of 180 kg / cm ² for 10 minutes. After that, the mirror plate with the film sandwiched is put in a water tank containing ice water as it is to cool it to a thickness of 1
A 00 μm polybutylene succinate film was obtained.

JIS K-7127 of the obtained film
The value of the tensile yield elongation measured according to the above was 30%.

The obtained film JIS K-71
The values obtained by dividing the tensile yield strength and the tensile fracture elongation by the tensile yield elongation measured in accordance with No. 27 are 36 MPa and 3 MPa, respectively.
It was 0.

The polybutylene succinate film was cut into a length of 200 mm and a width of 200 mm, and a molecular weight of 2 was cut in the center.
Approximately 1.5 g of polyethylene oxide (made by Aldrich) of 0,000 is placed, and the film and the polyethylene oxide are put into two 300 mm length × 300 mm width × 5 mm thickness.
It is sandwiched between SUS304 mirror surface plates made by SUS304, and a 37 ton press manufactured by Miura Press Co., Ltd. is used, and the high pressure side gauge pressure is 1 at 90 ° C.
A pressure of 50 kg / cm ² was maintained for 10 minutes.

Then, the mirror-finished plate with the film sandwiched was cooled in a refrigerator at 4 ° C. to obtain a laminated film (1) of the present invention.

The thickness of the obtained laminated film (1) is 15
It was 0 μm, and the polyethylene oxide layer could be easily peeled from the polybutylene succinate film.

The moisture permeability of the resulting laminated film is shown in Table 1.

Example 2 A 100 μm thick polybutylene succinate film obtained in the same manner as in Example 1 was cut into a length of 200 mm × width of 200 mm, and a length of 200 μm was cut on the cut film.
mm × width 200 mm polyvinyl alcohol film (Polymura Green Film SF-1, manufactured by Kei Nakamura Shokai, thickness:
25 μm), and place the two films in two lengths of 30
It was sandwiched between 0 mm × horizontal 300 mm × 5 mm mirror surface plates made of SUS304, and a 37 ton press manufactured by Miura Press Mfg. Co., Ltd. was used, and held at 90 ° C. under a high side gauge pressure of 150 kg / cm ² for 10 minutes.

Then, the mirror-finished plate with the film sandwiched was allowed to cool to room temperature to obtain the laminated film (2) of the present invention.

The thickness of the obtained laminated film (2) is 12
It was 0 μm, and the polyvinyl alcohol layer could be easily peeled from the polybutylene succinate film.

The moisture permeability of the obtained laminated film is shown in Table 1.

Example 3 5 g of polybutylene succinate pellets having a number average molecular weight of 40,000 were added to two 300 m lengths.
It was sandwiched between SUS304 mirror surface plates of m × width 300 mm × thickness 5 mm, and a 37 ton press manufactured by Miura Press Mfg. Co., Ltd. was used and held at 120 ° C. for 10 minutes at a pressure of 180 kg / cm ^{2 on} the high pressure side. Then, the mirror-finished plate with the film sandwiched was put into a water tank containing ice water and cooled to obtain a polybutylene succinate film having a thickness of 100 μm.

JIS K-7127 of the obtained film
The value of the tensile yield elongation measured according to the above was 30%.

The obtained film was JIS K-71.
The values obtained by dividing the tensile yield strength and the tensile fracture elongation by the tensile yield elongation measured in accordance with No. 27 are 36 MPa and 3 MPa, respectively.
It was 0.

The polybutylene succinate film was cut into a length of 200 mm and a width of 200 mm, and a molecular weight of 2 was cut in the center.
About 1.5 g of polyethylene oxide (manufactured by Aldrich) of 0,000 is placed, and the film and polyethylene oxide are sandwiched between two 300 mm long × 300 mm long × 5 mm thick mirror plates made of SUS304, manufactured by Miura Press Mfg. Co., Ltd. Using a 37-ton press, the high side gauge pressure 15 at 90 ° C
A pressure of 0 kg / cm ² was maintained for 10 minutes.

Then, the mirror-finished plate with the film sandwiched was cooled in a refrigerator at 4 ° C. to obtain a laminated film (1) of the present invention.

The thickness of the obtained laminated film (1) is 15
It was 0 μm, and the polyethylene oxide layer could be easily peeled from the polybutylene succinate film.

The moisture permeability of the obtained laminated film is shown in Table 1.

<Comparative Example 1> About 2.5 g of polyethylene oxide having a molecular weight of 200,000 was added to two 300 mm lengths × 30 widths.
It is sandwiched between 0 mm x 5 mm thick SUS304 mirror plate,
Using a 37-ton press manufactured by Miura Press Co., Ltd.
High pressure side gauge pressure at 0 ° C: 10 kg at a pressure of 150 kg / cm2
Hold for minutes.

Then, the mirror-finished plate with the film sandwiched was cooled in a refrigerator at 4 ° C. to obtain a film having a thickness of 50 μm.

The moisture permeability of the obtained laminated film is shown in Table 1.

<Comparative Example 2> Table 1 shows the water vapor transmission rate of the polyvinyl alcohol film (Polygreen film SF-1 manufactured by Nakamura Keishokai, thickness: 25 μm) used in Example 2.

COMPARATIVE EXAMPLE 3 Poly (3-hydroxybutyrate) powder (manufactured by Aldrich Co.) (5 g) was used in the length of 30 sheets.
It is sandwiched between 0 mm x 300 mm wide x 5 mm thick mirror plate made of SUS304, and a 37 ton press manufactured by Miura Press Mfg. Co., Ltd. is used, and the high side gauge pressure is 180 kg / cm ² at 180 ° C.
The pressure was held for 10 minutes. Thereafter, a mirror surface plate with the film sandwiched was put into a water tank containing ice water as it was and cooled to obtain a 170 μm-thick poly (3-hydroxybutyrate) film.

The film obtained was subjected to a tensile test in the same manner as in Example 1. The sample broke without reaching the yield point, and the tensile breaking strength and tensile breaking elongation at that time were 32 MPa and 16 MPa, respectively. %Met. Since the sample did not show a yield point, the value obtained by dividing the tensile elongation at break by the tensile yield elongation was infinite.

The poly (3-hydroxybutyrate) film was cut into a length of 200 mm and a width of 200 mm, and about 1.5 g of polyethylene oxide having a molecular weight of 200,000 (manufactured by Aldrich) was placed in the center. Length 300 mm x width 300 mm x thickness 5
The plate was sandwiched between SUS304 mm mirror-finished plates made of SUS304, and a 37-ton press manufactured by Miura Press Mfg. Co., Ltd. was used, and the plate was held at 90 ° C. under a high-pressure side gauge pressure of 150 kg / cm ² for 10 minutes.

Thereafter, the mirror-finished plate with the film sandwiched was placed in a methanol bath cooled to 0 ° C. and cooled to obtain a laminated film (1 ′).

The thickness of the obtained laminated film (1 ') is 1
90 μm, the polyethylene oxide layer is made of poly (3
-Hydroxybutyrate) film could be easily peeled off.

The moisture permeability of the obtained laminated film is shown in Table 1.

<Comparative Example 4> Instead of poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-3) was used.
-Hydroxyvalerate) powder (containing 22% of 3-hydroxyvalerate units, manufactured by Aldrich) was used in the same manner as in Comparative Example 3 to obtain poly (3- having a thickness of 160 μm.
A hydroxybutyrate-3-hydroxyvalerate) film was obtained.

The tensile yield elongation of the obtained film measured in the same manner as in Example 1 was 3%.

The tensile yield strength and tensile yield rupture elongation of the obtained film measured in the same manner as in Example 1 were 28 MPa and 6, respectively.

The poly (3-hydroxybutyrate-3)
-Hydroxy valerate) The film is cut into a length of 200 mm and a width of 200 mm, and about 1.5 g of polyethylene oxide having a molecular weight of 200,000 (manufactured by Aldrich) is placed in the center, and the film and polyethylene oxide are put into two 300 m lengths.
It was sandwiched between SUS304 mirror surface plates of m × width 300 mm × thickness 5 mm, and it was held for 10 minutes at 90 ° C. at a high pressure side gauge pressure of 150 kg / cm ² using a 37-ton press manufactured by Miura Press Co., Ltd.

Thereafter, the mirror-finished plate with the film sandwiched was placed in a methanol bath cooled to 0 ° C. and cooled to obtain a laminated film (2 ′).

The thickness of the obtained laminated film (2 ') is 1
80 μm, and the polyethylene oxide layer is made of poly (3
-Hydroxybutyrate-3-hydroxyvalerate)
It could be easily peeled from the film.

The moisture permeability of the obtained laminated film is shown in Table 1.

[0064]

[Table 1]

[0065]

INDUSTRIAL APPLICABILITY The laminated film of the present invention has low moisture permeability and is tough, and when it is used as a water-soluble packaging material, a resin layer which becomes unnecessary when the packaging material is put into an aqueous medium is extremely effective. It can be easily peeled off, and since the resin layer has biodegradability, it does not cause a waste problem. Therefore, the laminated film of the present invention is extremely useful as a packaging material for medicines, agricultural chemicals, fertilizers, detergents, water absorbent resins and the like.

[0066]

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[Procedure amendment]

[Submission date] March 10, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

Then, the laminated film (3) of the present invention was obtained by cooling the mirror plate with the film sandwiched in a refrigerator at 4 ° C.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

The thickness of the obtained laminated film (3) is 15
It was 0 μm, and the polyethylene oxide layer could be easily peeled from the polybutylene succinate film.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction content]

The moisture permeability of the obtained film is shown in Table 1.

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Claims (2)

[Claims] 1. A water-soluble resin layer (I) and the resin layer (I)
And a resin film (II) that is detachably temporarily attached, wherein the resin layer (II) is made of a biodegradable resin, and the tensile yield elongation of the resin layer (II) is 8% or more. A laminated film characterized by being. 2. The resin layer (II) is selected from the group consisting of poly (alkylene succinate), poly (ε-caprolactone), polyethylene-starch blend, poly (3-hydroxypropionate) and cellulose acetate. The laminated film according to claim 1 or 2, which is one kind or two or more kinds.