JP2696295B2 - Moisture transferable laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer film layer.
The present invention relates to a moisture-transferable laminated film in which moisture moves in one direction from one surface to the other surface of the resulting thin film material.

[0002]

2. Description of the Related Art Various thin film materials are used as food packaging materials for preserving, thawing and maintaining freshness of hydrated foods, shoes and clothing materials, medical materials, and agricultural materials. In this case, in use, it is often desired to have a property of preventing the intrusion of water or moisture from the outside and allowing the water or moisture inside to escape to the outside.

In order to solve this problem, a porous material having fine communication holes is used as a thin film material, and water is prevented from passing through the communication holes. Researches have been made to combine moisture and moisture permeability, and some have already been put to practical use.

[0004]

However, the above-mentioned moisture-permeable and waterproof material has a limitation that it can be applied only when one of the materials is liquid water and the other is water vapor. Taking the materials for shoes and clothing as an example, water does not penetrate from the outside to the inside even in rainy weather, but for the inside, while the amount of sweat is small, the inside moisture is scattered to the outside and does not cause stuffiness, When the amount of perspiration exceeds a certain limit, water vapor is condensed and is not radiated to the outside, causing discomfort.

[0005] It is difficult to find a thin film material in which the water vapor on the outer side does not move to the inner side, and the water vapor on the inner side moves to the outer side. Similarly, it is difficult to find a thin film material that does not allow water on the outside to enter the inside, and that transfers liquid water on the inside to the outside.

[0006] Under such circumstances, the present invention provides a polymer film regardless of whether water is liquid or water vapor.
It is an object of the present invention to provide a moisture-transferable laminated film in which moisture moves in one direction from one surface to the other surface of a thin film material made of a film layer .

[0007]

The moisture-permeable laminated film of the present invention comprises a high-moisture-permeable film layer (A) made of a polymer film layer and a low-moisture-permeable film layer (B) made of a polymer film layer . It is composed of a laminated film and laminated
Is the casting of the other layer-forming material on one layer, the layer (A)
Or an anchor coat capable of forming the layer (B)
Of the other layer forming material on one layer through the
Castable, capable of forming layer (A) or layer (B)
Adhesive lamination of layer (A) and layer (B) via adhesive layer, piece
Extrusion coating of the other layer-forming material on one layer
Or coextrusion of both layers
And moisture is high.
Low moisture permeable film from surface of moisture permeable film layer (A) side
Laminate fill that transitions in one direction towards the layer (B) side surface
The high moisture permeability film layer (A) and the low moisture permeability film layer (B)
The moisture permeability (g / m ² · 24 hr) at a temperature of 40 ° C. and a relative humidity of 90% RH based on Z0208 is Pa and P, respectively.
When b, a combination of Pa ≧ 300 (1) Pb ≧ 100 (2) Pa ≧ 3 × Pb (3) is used. is there.

Hereinafter, the present invention will be described in detail.

The moisture permeability Pa of the high moisture permeability film layer (A) is
As described in (1) above, 300 g / m ² · 24 hr or more (preferably 40
0 g / m ² · 24 hr or more), and when the moisture permeability is insufficient, the desired water transfer property cannot be obtained. Since the low moisture permeability film layer (B) is also required to have a certain degree of moisture permeability, its moisture permeability is 100 g /
it is necessary that m is ² · 24hr or more. When the moisture permeability Pb of the low moisture permeability film layer (B) is smaller than the above range,
Even if the high moisture permeable film layer (A) is laminated, a water-migrating laminated film cannot be obtained.

Further, the high moisture permeable film layer (A) and the low moisture permeable film layer (B) satisfy the relationship of the above (3), that is, the moisture permeability Pa of the high moisture permeable film layer (A). Must be at least three times (preferably at least four times) greater than the moisture permeability Pb of the low moisture permeability film layer (B),
If the ratio is less than three times, even if both layers have relatively high moisture permeability, the moisture transfer will not be carried out smoothly.

Examples of the high moisture permeable film layer (A) include:
Polyvinyl alcohol, ethylene-vinyl alcohol copolymer, N-methoxy-6-nylon, polyacrylate, poolivinyl ether, polyvinylpyrrolidone, polyethylene oxide, cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, carboxymethyl cellulose, methyl cellulose ,
Cellophane, natural polymer or processed product thereof (gelatin, casein, glue, albumin, alginate, pectin salt, chitosan, chitin, pullulan, zein, keratin, etc.), polyester urethane, polyurethane, ultraviolet curable resin having a hydrophilic group And other polymer film layers. The high moisture permeable film layer (A) may have water solubility depending on the application, but it is preferable that the high moisture permeable film layer (A) has hydrophilicity without water solubility. Therefore, measures such as blending of a crosslinking agent, copolymerization modification, graft modification, post-modification such as urethanization, acetalization, and cyanoethylation, irradiation with active energy rays, stretching, heat treatment, and conversion to insoluble salts are taken as necessary. be able to.

Examples of the low moisture permeable film layer (B) include:
Polycarbonate, crosslinked phenoxy ether resin,
UV curable resin, polysulfone, nylon, cellulose propionate, ethylene-vinyl alcohol copolymer with relatively high ethylene content, polystyrene, polyimide, polyurethane, polyester, polyether, etc.
A polymer film layer.

However, whether the film layer is a high moisture permeability film layer (A) or a low moisture permeability film layer (B) is relative, and the moisture permeability is greatly affected by the film thickness and the copolymer composition. So even if the same polymer, high moisture permeability film layer
It may belong to (A) or low moisture permeable film (B). In addition, even if the film is considered to have a very small moisture permeability, the moisture permeability increases when the film thickness is reduced. Becomes smaller. Therefore, the above example is for convenience only.

The high moisture permeable film layer (A) can be a single layer or a multi-layer. Similarly, the low moisture permeable film layer (B)
Can be a single layer or a multilayer.

[0015] The lamination can be carried out by forming a casting film forming method and the other layer on the one layer. In this case, in order to improve the interlayer adhesion, the upper layer can be cast via an anchor coating layer belonging to the high moisture permeable film layer (A) or the low moisture permeable film layer (B). It is possible to form a high moisture permeability film layer (A) or a low moisture permeability film layer (B) using commercially available high moisture permeability film layers (A) and low moisture permeability film layers (B). It is also preferable to perform adhesive lamination through an adhesive layer. The lamination of the high moisture permeable film layer (A) and the low moisture permeable film layer (B) is performed by coextrusion of both layer forming materials and extrusion of the other layer forming material on one layer. it can also be carried out by the coating.

The thickness of each layer is not particularly limited, but the high moisture permeable film layer (A) is often about several μm to 500 μm, and the low moisture permeable film layer (B) is usually about 1 to 100 μm.

The moisture-transferable laminated film composed of the laminated film of the high moisture permeable film layer (A) and the low moisture permeable film layer (B) has a odor that does not impair the purpose of the present invention.
In addition, another layer such as a web such as a nonwoven fabric, a woven fabric, a knitted fabric, or paper may be added on at least one of the layers, or may be interposed between the layers (A) and (B). .

The moisture transferable laminated film of the present invention is a food packaging material for preserving, thawing and maintaining freshness of hydrated foods,
Pharmaceutical packaging materials, medical or body materials (such as plasters,
Bandages, diaper covers, etc.), shoes and clothing materials (rainwear, outerwear, sportswear, etc.), fertilizer packaging materials, agricultural materials, building materials, wall protection materials, color films and the like.

[0019]

[Function] A laminated film is formed by using a combination that satisfies the above-mentioned relationships (1), (2), and (3) as the high moisture permeability film layer (A) and the low moisture permeability film layer (B). Then
Regardless of whether the moisture is liquid or water vapor, the moisture transfer property allows moisture to move in one direction from the surface on the high moisture permeability film layer (A) side to the surface on the low moisture permeability film layer (B) side It becomes a laminated film.

[0020]

The present invention will be further described with reference to the following examples. Hereinafter, "parts" refers to parts by weight.

Example 1 FIG. 1 is a cross-sectional view showing an example of the moisture transferable laminated film of the present invention. The white arrow in FIG. 1 indicates the direction of water transfer.

It consists of 40 parts of a phenoxy ether resin (manufactured by Union Carbide Co.), 40 parts of methyl ethyl ketone, and 40 parts of a 75% solution of adduct of tolylene diisocyanate and trimethylolpropane (Coronate L manufactured by Nippon Polyurethane Co., Ltd.). A phenoxy ether resin-based resin solution was prepared.

The above-mentioned phenoxy ether resin solution is applied to one surface of a polyvinyl alcohol film (heat treated product) having a degree of polymerization of 1100, a degree of saponification of 98.5 mol% and a thickness of 75 μm as an example of the high moisture permeable film layer (A). , And dried at a temperature of 80 ° C. for 5 minutes, and then cured at a temperature of 120 ° C. for 20 minutes to form a low moisture-permeable film layer (B) having a thickness shown in Table 1.

As a result, a water-migrating laminated film having the layer constitution of (A) / (B) shown in FIG. 1 was obtained. Table 1 shows the measurement results of the moisture permeability (g / m ² · 24 hr) of this laminated film.
The moisture permeability is measured at a temperature of 40 ° C. and a relative humidity of 90% RH based on JIS Z0208 (Method of testing moisture permeability of moisture-proof packaging material (cup method)). The moisture permeability Pa of the single film of the layer (A) and the moisture permeability Pb of the single film of the layer (B) are as follows. Single film of moisture permeability Pa thickness 75μm of layer (A): 2400g / m single film of moisture permeability Pb thickness 8μm of ² · 24 hr or layer ^{(B): 180g / m 2} · 24hr Thickness 15μm: 130g / m ² · 24hr

[0025]

[Table 1] Layer (A) / layer (B) layer (A) → a layer (B) direction of the layer (B) → a layer (A) thickness in the direction of (μm / μm) moisture permeability (g / m ² · 24hr) Moisture Permeability ^{(g / m 2 · 24hr)} 75/4 663.5 182.8 75/6 372.5 108.7 75 / 8.5 183.4 56.5 75/10 115.2 50.4 75/15 114.2 30.3

From Table 1, it can be seen that the moisture permeability in the layer (A) → layer (B) direction is large, and that the moisture permeability in that direction is significantly larger than the moisture permeability in the layer (B) → layer (A) direction. I understand.

Comparative Example 1 One side of the polyvinyl alcohol film of Example 1 as an example of the high moisture permeable film layer (A) was coated with methanol, glycol ether, acetic acid and water as solvents at a weight ratio of 5%.
A silicone resin liquid (acrylic silicone resin liquid) having a resin content of 23% by weight used in a ratio of 1: 17: 2: 7 was cast using an applicator and dried at a temperature of 60 ° C. for 5 minutes.
Then, the film was cured at a temperature of 100 ° C. for 7 minutes to form a low moisture permeable film layer (B ′) having a thickness shown in Table 2.

The moisture permeability of the obtained laminated film (g / m ² · 24
hr) are shown in Table 2. The moisture permeability Pa of the single film of the layer (A) and the moisture permeability Pb 'of the single film of the layer (B') are as follows. Single film of moisture permeability Pa thickness 75μm of layer ^{(A): 2400g / m 2} · 24hr layer (B ') of the single film of moisture permeability Pb' thickness ^{6μm: 25.3 g / m 2 ·} 24hr

[0029]

[Table 2] Layer (A) / layer (B ') a layer of (A) → a layer (B') direction of the layer (B ') → a layer (A) thickness in the direction of (μm / μm) moisture permeability (g / m ² · 24hr ) moisture permeability ^{(g / m 2 · 24hr)} 75/2 35.9 30.0 75/4 25.8 30.8 75/6 25.3 40.9

From Table 2, it can be seen that the moisture permeability in the layer (A) → layer (B ′) direction and the moisture permeability in the layer (B ′) → layer (A) direction are both small, and the moisture permeability in both directions is not so different. You can see that. This is a low moisture permeable film layer consisting of a silicone resin film (B ')
Has low moisture permeability, which means that moisture transferability is practically not exhibited regardless of the lamination of the high moisture permeability film layer (A).

Comparative Example 2 A silicone resin liquid of a different type from that of Comparative Example 1 was cast on one surface of the polyvinyl alcohol film of Example 1 as an example of the high moisture permeable film layer (A) using an applicator. After drying and curing, a low moisture permeable film layer (B ') having the thickness shown in Table 3 was formed.

The moisture permeability (g / m ² · 24
hr) are shown in Table 3. The moisture permeability Pa of the single film of the layer (A) and the moisture permeability Pb 'of the single film of the layer (B') are as follows. Moisture permeability Pa of the single film of the layer (A) Thickness 75 μm: 2400 g / m ² · 24 hr Moisture permeability Pb ′ of the single film of the layer (B ′) 6 μm: 30 g / m ³ · 24 hr

[0033]

[Table 3] Layer (A) / layer (B ') a layer of (A) → a layer (B') direction of the layer (B ') → a layer (A) thickness in the direction of (μm / μm) moisture permeability (g / m ² · 24hr ) moisture permeability ^{(g / m 2 · 24hr)} 75/2 54.9 51.1 75/4 48.5 45.7 75/6 39.1 41.0

From Table 3, it can be seen that the moisture permeability in the layer (A) → layer (B ′) direction and the moisture permeability in the layer (B ′) → layer (A) direction are both small, and the moisture permeability in both directions is not so different. You can see that.

Example 2 FIG. 2 is a cross-sectional view showing an example of the moisture transferable laminated film of the present invention. The white arrow in FIG. 2 indicates the direction of water transfer.

A polyvinyl alcohol film having a degree of polymerization of 1100, a saponification degree of 98.5 mol% and a thickness of 60 μm as an example of the high moisture permeable film layer (A ₁ ), and a low moisture permeable film layer
A commercially available nylon 6 film having a thickness of 7 μm as an example of (B) was laminated by bonding using an aqueous solution of N-methoxy-6-nylon as an adhesive and dried. The formed adhesive layer becomes a high moisture permeable film layer (A ₂ ) having a thickness of 5 μm.

As a result, (A ₁ ) / (A ₂ ) / (B) shown in FIG.
Thus, a moisture transferable laminated film having the following layer constitution was obtained. The measurement results of the moisture permeability (g / m ² · 24 hr) of this laminated film were as follows. Layer (A ₁ ) → Layer (A ₂ ) → Layer (B) direction 420 g / m ²・ 24 hr Layer (B) → Layer (A ₂ ) → Layer (A ₁ ) direction 130 g / m ²・ 24 hr

The moisture permeability Pa of the single film of the layers (A ₁ ) and (A ₂ )
The moisture permeability Pb of the single film of the layer (B) is as follows. Moisture permeability Pa thickness of the single film of the layer (A ₁ ) 60 μm: 2600 g / m ² · 24 hr Moisture permeability Pa thickness of the single film of the layer (A ₂ ) 5 μm: 2200 g / m ² · 24 hr of the single film of the layer (B) moisture permeability Pb thickness 7μm: 400g / m ² · 24hr

Example 3 Example 2 was repeated except that an ethylene-vinyl alcohol copolymer film having a thickness of 8 μm and an ethylene content of 23 mol% was used as the low moisture permeable film layer (B).

Thus, (A ₁ ) / (A ₂ ) / (B) shown in FIG.
Thus, a moisture transferable laminated film having the following layer constitution was obtained. The measurement results of the moisture permeability (g / m ² · 24 hr) of this laminated film were as follows. The moisture permeability Pb of the single layer (B) is 130.
a g / m ² · 24hr. Layer (A ₁ ) → Layer (A ₂ ) → Layer (B) direction 118 g / m ²・ 24 hr Layer (B) → Layer (A ₂ ) → Layer (A ₁ ) direction 34 g / m ²・ 24 hr

Example 4 Example 2 was repeated except that a 80 μm thick cellulose triacetate film was used as the low moisture permeable film layer (B).

Thus, (A ₁ ) / (A ₂ ) / (B) shown in FIG.
Thus, a moisture transferable laminated film having the following layer constitution was obtained. The measurement results of the moisture permeability (g / m ² · 24 hr) of this laminated film were as follows. The moisture permeability Pb of the single film of the layer (B) is 630.5
a g / m ² · 24hr. Layer (A ₁ ) → layer (A ₂ ) → layer (B) direction 295 g / m ²・ 24 hr Layer (B) → layer (A ₂ ) → layer (A ₁ ) direction 125 g / m ²・ 24 hr

Example 5 The thickness of the layer (A) / layer (B) obtained in Example 1 was 75 μm / 15
The frozen fish was prepared by laminating the laminated film of μm, the laminated film obtained in Example 2, the laminated film obtained in Example 3, and the laminated film obtained in Example 4 such that the layer (A) side was inside. Wrapped and sealed and stored in the freezer for 3 days. This was taken out of the freezer and thawed in a microwave oven. For comparison, fish that were hermetically sealed and packaged with a polyvinylidene chloride film and stored in a freezer were similarly thawed.
Comparing the two, when wrapped with the moisture-transferable laminated film of the present invention, the free water was removed, so that it was significantly advantageous in terms of fish taste retention.

[0044]

As described in the section of operation, in the present invention, the high moisture permeable film layer (A) and the low moisture permeable film layer (B) are described above as (1), (2), and ( 3)
Employs a combination that satisfies the relationship, and certain layered
Since the laminated film is formed by the method , regardless of whether the moisture is liquid or water vapor, moisture is directed from the surface on the high moisture permeable film layer (A) side to the surface on the low moisture permeable film layer (B) side. Move in one direction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a moisture-transferable laminated film of the present invention.

FIG. 2 is a cross-sectional view showing an example of the moisture transferable laminated film of the present invention.

[Explanation of symbols]

(A), (A ₁ ), (A ₂ )… High moisture permeability film layer (B)… Low moisture permeability film layer

Claims (1)

(57) [Claims] 1. A a laminated film of high humidity film layer made of a polymer film layer (A) and low moisture permeability film layer made of a polymer film layer (B), and laminating the both layers
Is an anchor capable of forming a layer (A) or a layer (B) by casting the other layer-forming material on one layer.
-One layer layer on one layer via a coating layer
Adhesive capable of casting component material and forming layer (A) or layer (B)
Adhesive lamination of layer (A) and layer (B) via layers, extrusion of one layer on the other layer forming material
It is made by either coating or co-extrusion of the material forming both layers , and has high moisture permeability
Low moisture permeability film layer from the surface of the film layer (A) side
(B) Laminated film that moves in one direction toward the surface on the side
The high moisture permeability film layer (A) and the low moisture permeability film layer (B) are JIS Z of these layers.
The moisture permeability (g / m ² · 24 hr) at a temperature of 40 ° C. and a relative humidity of 90% RH based on 0208 is Pa and Pb, respectively.
Where Pa ≧ 300 (1) Pb ≧ 100 (2) Pa ≧ 3 × Pb (3) Laminated film.