JPH10258484A - Film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film having high waterproof performance by incorporating high moisture permeable performance. SOLUTION: This film is formed by laminating two types of nonporous resin layers. In this case, a ratio of dew formation amount at a resin layer A side to that of resin layer B side is 2 or more and a thickness of the layer B is 5 to 50μm. And, the layer A is formed of polyurethane resin, and the layer B is formed of elastomer. And moisture permeability from the layer B side is preferably 3000 g/m<2> .24 hr or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a moisture-permeable film. More specifically, the present invention relates to a film having high moisture permeability and high waterproof performance and a method for producing the same.

[0002]

2. Description of the Related Art Hitherto, as a means for improving the moisture permeability of a moisture-permeable waterproof material utilizing a coating, a method of improving the moisture permeability of a coating layer has been regarded as an effective means.

[0003] In the case of non-porous membranes, high moisture permeability has been achieved by making the membranes themselves hydrophilic, providing a three-dimensional helical structure gap to the soft segment portion, and the like. In the case of a porous membrane, high moisture permeability has been performed by increasing the porosity.

[0004] In recent years, from the viewpoint of comfort, a further increase in moisture permeability has been aimed at for the purpose of suppressing stickiness and stuffiness due to dew condensation in clothes, and an approach method for further increasing moisture permeability of the moisture-permeable waterproof membrane layer. In both the non-porous film and the porous film, thinning has been practiced as an effective means.

[0005] However, thinning alone causes problems such as rubbing due to a decrease in film strength and abrasion resistance, and thus sacrificing the waterproof performance of the material itself. At present, a wet film is desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film excellent in moisture permeability and water resistance and a method for producing the same in view of the above-mentioned situation.

[0007]

The film according to the present invention has the following structure to solve the above-mentioned problems.

That is, two types of non-porous resin layers are laminated, the ratio of the amount of condensation on the resin A layer side to the amount of condensation on the resin B layer side is 2 or more, and the thickness of the resin A layer is 0.
A film characterized by having a thickness of 1 to 10 μm and a thickness of the resin B layer of 5 to 50 μm.

Further, a method for producing a film according to the present invention has the following constitution in order to solve the above-mentioned problems.

That is, a resin A having a water absorption swelling ratio of less than 1% when coated on a release support and a water absorption swelling ratio of 1% when coated.
A method for producing a film, comprising applying a resin B of 0% or more, subjecting the resin to a heat treatment, forming a film, and releasing a resin film from a release support to form a film. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The film of the present invention comprises two types of non-porous resin layers laminated, wherein the ratio of the amount of condensation on the resin A layer side to the amount of condensation on the resin B layer side is 2 or more. The thickness of the layer is 0.1 to 10 μm, and the thickness of the resin B layer is 5 to 50 μm.
m.

In the present invention, the phrase “two kinds of non-porous resin layers are laminated” means a state in which different resin films are adhered and overlap.

The “non-porous” of the non-porous resin layer referred to here means “pore” at these resolutions when observed with a scanning electron microscope (hereinafter abbreviated as SEM) and a transmission electron microscope (hereinafter abbreviated as TEM). Refers to a state in which observation is impossible, and generally refers to a state in which "pores" of 20 nm or more do not exist in a non-swelling state.

The "holes" in this case do not include closed cells generated in a film in a manufacturing process or the like, pinholes generated by physical stimulation, defects, and the like.

In the present invention, the ratio of the amount of condensation on the resin A layer side to the amount of condensation on the resin B layer side is 2 or more. In the present invention, the side with the larger amount of dew is defined as the resin A layer side, and the side with the smaller amount of dew is defined as the resin B layer side.

In the present invention, the resin A layer has a thickness of 0.1 mm.
It is a continuous layer having a thickness of 1 to 10 μm, and the resin B layer laminated on the resin A layer is a continuous layer having a thickness of 5 to 50 μm.

In the present invention, there is a difference in the mobility of water from the resin A layer side or the resin B layer side to the inside of the film.

Specifically, the resin A layer is a resin layer that does not allow water to pass in the liquid phase but allows water to pass in the gas phase.
Since the layer is a resin layer (water-absorbing film) that allows water to pass through both the liquid phase and the gas phase, a difference may occur in the mobility of water.

The amount of dew condensation on the resin B layer side means that when the resin B layer is in contact with the water vapor layer, the amount of water or moisture absorbed on the film surface is determined.
The amount of excess water vapor exceeding the water vapor discharge capacity, which is the amount of water vapor that can permeate through the resin A layer from the layer, becomes water droplets on the surface of the resin B layer. When water comes in contact with the water vapor layer, excess water vapor exceeding the water vapor discharge capacity, which is the amount of water absorption or moisture absorption to the membrane surface, and the amount of water vapor that can be transmitted from the resin A layer through the resin B layer, becomes water droplets on the surface of the resin A layer. It means the amount that became.

In the present invention, the amount of dew condensation from the resin A layer side to the amount of dew condensation from the resin B layer side is 2 or more. When the amount of condensation from the layer of the resin A is 2 or more with respect to the amount of condensation from the layer of the resin B, the amount of condensation from the layer of the resin A is twice or more that of the layer of the resin B in any case. Say.

In the present invention, the thickness of the resin A layer is 0.1.
1 to 10 μm. In the present invention, the film thickness is 0.1 μm.
If the thickness is smaller than m, there is a problem that it is difficult to control the film formation. On the other hand, if it exceeds 10 μm, there is a problem that the moisture permeability is extremely reduced.

A water-impermeable hydrophobic membrane; and
From the viewpoint of not impairing the moisture permeability, the resin A layer has a thickness of 0.3
The range is preferably from 8 to 8 μm, more preferably from 0.5 to 5 μm.

In the present invention, the thickness of the resin B layer is 5 to 50 μm. In the present invention, if the thickness of the resin B layer is less than 5 μm, there is a problem in handling the film. On the other hand, if it exceeds 50 μm, there is a problem that the moisture permeability of the film is reduced. The thickness of the resin B layer is preferably in the range of 10 to 30 μm from the viewpoint of necessity to be a support film of the resin A layer.

In the present invention, in consideration of the stretchability of the laminated film, even when laminated with a thick film, the resin A layer is made of polyurethane from the viewpoint that the ability to follow a thin film is very excellent. It is preferably a resin.

The polyurethane resin used in the present invention refers to a copolymer obtained by reacting a polyisocyanate and a polyol.

As the isocyanate component, an aromatic diisocyanate, an aliphatic diisocyanate or an aliphatic diisocyanate alone or a mixture thereof is used. For example, tolylene 2,4-diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,6-hexamethylene Using diisocyanate, 1,4-cyclohexane diisocyanate, etc., as the polyol component, use a polyether polyol, polyester polyol, polyether polyol using polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., polyester polyol, Reaction products of diols such as ethylene glycol and propylene glycol with dibasic acids such as adipic acid and sebacic acid and caprolact It can be used ring-opening polymerization of such. In addition, ether / ester type, amide type, and carbonate type can also be appropriately used.

The urethane resin used for the resin A layer is as follows:
Among them, those having low swelling property when in contact with water are preferable.

Further, the resin B layer is preferably a film that can transmit water in a liquid phase or a gas phase, and it is preferable to use an elastomer having a water absorbing function.

The elastomer used in the present invention includes:
Styrene-based elastomer, olefin-based elastomer,
Urethane-based elastomers, ester-based elastomers, polyamide-based elastomers, and the like can be used.

Specifically, styrene-based elastomers include copolymers of polybutadiene and polystyrene and copolymers of polyisoprene and polystyrene, and olefin-based elastomers include ethylene / propylene / polystyrene.
Copolymers of methylene and polypropylene, urethane-based elastomers are copolymers of diisocyanates with short-chain glycols bonded and diisocyanates with long-chain polyols bonded, and ester-based elastomers are polyethylene terephthalates. Polyamide-based elastomers such as copolymers of high molecular weight polyethylene ether glycol and copolymers of polybutylene terephthalate and high molecular weight polyalkylene ether glycol, and hydrophilic polyamides such as copolymers of nylon 6 and polyether Can be used.

In particular, water-swellable elastomers such as urethane elastomers, ester elastomers and polyamide elastomers can be preferably used.

Taking into account the relaxation of the structure and the decrease in strength due to water absorption swelling, water-absorbing elastomers are preferred, and urethane-based elastomers are particularly preferred.

In the present invention, the moisture permeability from the resin B surface side is preferably at least 30,000 g / m ² · 24 hr from the viewpoint of comfort when dew is condensed on the film and a wide range of application.

The moisture permeability in the present invention is defined as JIS L 1
099 This refers to the evaluation of moisture permeability by the potassium acetate method.

This method assumes a particularly large amount of perspiration, and assumes moisture permeation in a state where dew is formed in the clothes.

Normally, sweat is discharged from the inside of the garment through the resin layer in the form of water vapor to the outside of the garment, so that in the state where no dew is formed in the garment, the conventional material can sufficiently cope with it.

However, when the amount of perspiration increases and dew condensation occurs in the clothes, the system becomes in contact with liquid water,
A major issue is how to drain the sweat that has condensed out of the clothes, and more moisture must be permeable.

Next, a method for producing the film of the present invention will be described.

In the method for producing a film of the present invention, a resin A having a water absorption swelling ratio of less than 1% when coated and a resin B having a water absorption swelling ratio of 10% or more when coated are coated on a release support. After heat treatment and film formation, the resin film is released from the release support.

The release support used in the present invention refers to a material such as taffeta fabric, film, paper, etc., which has a smooth surface and a low affinity for a resin film formed on the support. Usually, release paper or film coated with a silicone resin, release paper laminated with polypropylene, or the like can be preferably used.

In the present invention, the water swelling ratio at the time of coating is 1
% Is a resin having a linear swelling ratio of less than 1% when a resin film having a thickness of 30 μm is immersed in water, which means that the resin itself has a very low water absorption. .

The resin having a water absorption swelling ratio of 10% or more at the time of coating refers to a resin having a linear swelling ratio of 10% or more when a resin film having a thickness of 30 μm is immersed in water. It means that the water absorption of the resin itself is very high. Coating the resin A layer and the resin B layer on the release support means that the resin A is coated on the release support and then the resin B film is formed in a laminated form, or the resin B is coated. ,
Subsequently, it means that a resin A layer coating is formed in a laminated form.

Generally, the resin solution is applied by using a coating formulation such as knife over roll coating, direct roll coating, reverse roll coating, gravure coating, and the like, in which the coating amount is appropriately set so as to have a desired film thickness. At a temperature of 50 ° C to 150 ° C,
It is preferable to dry and form a film under the conditions of 0.5 to 10 minutes.

In forming a film, it is preferable to appropriately use an isocyanate compound as a crosslinking agent in the resin solution for the purpose of improving solvent resistance and film strength.

As the isocyanate compound, 2,4-
Tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or triisocyanates obtained by the addition reaction of 3 moles of these diisocyanates with 1 mole of a compound containing active hydrogen can be used.

These isocyanates may be in a form in which an isocyanate group is liberated, or in a form in which phenol or methyl ethyl ketoxime is added to stabilize the compound and then heat-treated to dissociate the block. It may be properly used depending on workability and use.

By the above method, a film can be produced, and the film can be used alone by peeling it from the release support.

With such a structure, the function of the present invention is to make the hydrophobic film thinner to make it highly moisture-permeable, and to compensate for the decrease in water pressure due to the decrease in film strength due to the thinner film with the water-absorbing resin.
It is considered that the low water pressure of the water absorbent resin is achieved by a mutual complementation function of supplementing the low water pressure with a hydrophobic film (water resistant thin film).

Further, as shown by the difference in the amount of dew condensation, the film exhibits anisotropy in water absorption or hygroscopicity and moisture permeability from the front and back of the film, and has a moisture permeability of 30,000 g / m ² assuming condensation.・ By being 24 hours or more,
Comfort under all conditions can be obtained.

The present invention can be used as a moisture-permeable and waterproofing film, or when used in clothing materials, in addition to outdoor wear such as fishing and mountaineering clothes, ski-related wear, windbreakers, athletic wear, golf wear rainwear, and casual coats. , Outdoor work clothes, gloves,
It can also be used for shoes and the like.

[0052]

The present invention will be described in more detail with reference to the following examples.

The evaluation method of the present invention is described below.

[Moisture Permeability] Measured according to the JIS L 1099 potassium acetate method.

[Amount of Dew Condensation on Membrane Surface] A 500 ml beaker is filled with hot water at 1.70 ° C., the water surface and the film surface are kept at a constant interval, and one side is on the beaker side.

2. After the standing, the weight of the droplet generated on the film surface facing the beaker side was measured. The dew condensation amount from the A layer side and the B layer side was measured, and the dew condensation ratio of the A layer to the B layer was calculated.

[Measurement of Film Thickness] The cross section of the film was observed by SEM, and the average of the length from the film-film interface to the surface of each resin layer was defined as the film thickness of each resin layer.

[Water absorption swelling ratio] A single resin film having a thickness of 30 μm was immersed in water (23 ° C.) filled in a vat for 24 hours.

2. After immersion, the rate of change in linear length (linear swelling rate) due to film swelling was taken as the water absorption swelling rate.

Example 1 A hydrophobic polyurethane elastomer having a water absorption swelling ratio of 1% was prepared using DMF: MEK (weight ratio = 1: 1).
3) to prepare a 10% by weight resin solution. A resin A solution was prepared by adding 9 parts of an aromatic polyisocyanate as a crosslinking agent and 2 parts of an amine component as a reaction accelerator to the resin weight.

Further, 30 parts of methyl ethyl ketone was added to 100 parts of a water-absorbing polyurethane elastomer having a water absorption swelling ratio of 17% to prepare a resin B solution. The resin A solution is applied on a release film, dried at 120 ° C. for 5 minutes, and dried at 150 ° C. for 5 minutes.
After curing for a minute, a resin A layer was formed.

Next, a resin B solution was applied on the formed resin A layer and dried at 120 ° C. for 5 minutes to form a coating.

The film of the present invention was obtained by peeling from the release film. The thickness of the resin A layer is 2.8 μm,
The thickness of the resin B layer was 10.3 μm.

As shown in Table 1, the moisture permeability is 84,500 g
/ M ² · 24 hr, which was excellent in moisture permeability, and the ratio of the amount of dew condensation on the layer B side to the amount of dew condensation on the side of the layer A was 3.8, giving a difference between the front and back sides.

[0065]

[Table 1] Example 2 A film was produced in the same manner as in Example 1 except that the coating was performed so that the thickness of the resin B layer was 20 μm.

The thickness of the resin A layer was 2.8 μm, and the thickness of the resin B layer was 20.1 μm.

As shown in Table 1, the moisture permeability was 56,000 g.
/ M ² · 24 hr, excellent in moisture permeability, and the ratio of the amount of dew condensation on the B layer side to the amount of dew condensation on the A layer side was 5.3, which was a difference between the front and back sides.

Example 3 A film was manufactured in the same manner as in Example 1 except that the resin B layer was applied so as to have a thickness of 30 μm.

The thickness of the resin A layer was 2.8 μm, and the thickness of the resin B layer was 31.0 μm.

As shown in Table 1, the moisture permeability was 38,000 g.
/ M ² · 24 hr, excellent in moisture permeability, and the ratio of the amount of dew condensation on the layer B side to the amount of dew condensation on the layer A side was 6.0.

Example 4 A film was produced in the same manner as in Example 1 except that the resin A layer was coated so as to have a thickness of 6 μm.

The thickness of the resin A layer was 6.2 μm, and the thickness of the resin B layer was 10.1 μm.

As shown in Table 1, the moisture permeability was 50 or 100 g.
/ M ² · 24 hr, excellent in moisture permeability, and a ratio of the amount of dew condensation from the B layer side to the amount of dew condensation from the A layer side was 7.6. Comparative Example 1 A film was produced in the same manner as in Example 1 except that the thickness of the resin A layer was changed to 0.08 μm.

The thickness of the resin A layer could not be measured due to a defect, and the thickness of the resin B layer was 10.1 μm.

As shown in Table 1, although the moisture permeability is excellent, the ratio of the amount of condensation from the layer B to the amount of condensation from the layer A is small because the layer A is thin and there is a defect in the film, and there is almost no difference between the front and back sides. It was a film.

Comparative Example 2 A film was produced in the same manner as in Example 1 except that the thickness of the resin A layer was changed to 12 μm.

The thickness of the resin A layer was 11.8 μm, and the thickness of the resin B layer was 10.3 μm.

As shown in Table 1, since the hydrophobic resin A layer is thick, moisture permeability is low.
The film had a large difference between the front and back sides with a large dew condensation ratio from the layer side.

Comparative Example 3 A film was produced in the same manner as in Example 1 except that the thickness of the resin B layer was 3 μm.

The thickness of the resin A layer was 2.8 μm, and the thickness of the resin B layer was 2.8 μm.

As shown in Table 1, the moisture permeability is excellent, but since the layer B is thin, the ratio of the amount of condensation from the layer B to the amount of condensation from the layer A is small. There was no film.

Comparative Example 4 A film was produced in the same manner as in Example 1 except that the thickness of the resin B layer was changed to 60 μm.

The thickness of the resin A layer was 61.0 μm, and the thickness of the resin B layer was 2.8 μm.

As shown in Table 2, the film is hydrophilic but has a low moisture permeability due to the thick resin A layer and a large difference between the front and back sides in the ratio of the amount of condensation from the layer B to the amount of condensation from the layer A. there were.

[0085]

According to the present invention, a film having high moisture permeability and high waterproofness can be obtained.

Claims (4)

[Claims] 1. A laminate comprising two types of non-porous resin layers,
The ratio of the amount of condensation on the resin A layer side to the amount of condensation on the resin B layer side is 2 or more, and the thickness of the resin A layer is 0.1 to 10 μm.
m, a film characterized in that the thickness of the resin B layer is 5 to 50 μm. 2. The film according to claim 1, wherein the resin A layer is formed of a polyurethane resin, and the resin B layer is formed of an elastomer. 3. The moisture permeability from the resin B layer side is 30,000 g /
The film according to claim 1, wherein the film has a length of m ² · 24 hr or more. 4. A swelling rate of water upon coating on a release support of 1%.
The resin A having a swelling ratio of less than 10% and the resin A having a water absorption swelling ratio of 10% or more are coated, and the resin is subjected to a heat treatment to form a film. A method for producing a film, characterized by being formed.