JP2002143656A - Moisture permeable material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture permeable material excellent in mechanical strength, fablicability, water resistance, or the like. SOLUTION: This moisture permeable material is a composition obtained by blending a potassium ionomer having 8-30 wt.% unsaturated carboxylic acid content and >=50% degree of neutralization or an alkali metal ionomer having 8-30 wt.% unsaturated carboxylic acid content and >=50% degree of neutralization with a hydrophilic compound and has >=0.02 g/m/day moisture permeability coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a moisture-permeable material comprising an ionomer of an ethylene / unsaturated carboxylic acid copolymer.

[0002]

2. Description of the Related Art Sanitary materials such as disposable diapers and sanitary products,
DESCRIPTION OF RELATED ART In clothing such as coats, packaging materials for certain foods and flowers, moisture-permeable materials that allow moisture to pass through selectively are being used. A typical example is a microporous film obtained by forming a sheet of a polyolefin containing a fine powdery inorganic filler and then stretching the sheet. In this type of moisture-permeable material, water resistance decreases when the pore size is too large in order to increase the moisture permeability, but according to the above-described manufacturing method, the pore size for balancing the degree of moisture permeability and the degree of water resistance is reduced. Adjustment was difficult and water resistance was often sacrificed. Also, when the amount of the inorganic filler was increased, the sheet strength was weakened, and the moldability was impaired. Furthermore, since it is microporous, it has been disliked in the field of sanitary materials that almost all odor components pass therethrough.

As a material different from such a microporous moisture-permeable material, a moisture-permeable material made of a film such as a polyester elastomer, a polyamide elastomer, or a urethane elastomer containing a substantial amount of polyether units in a molecule is known. However, these are expensive, and have problems such as being too flexible for some applications, and having high tackiness and easy blocking.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to easily adjust moisture permeability, flexibility, and the like.
Another object of the present invention is to provide a nonporous moisture-permeable material which is excellent in mechanical strength, moldability, water resistance and the like and free from blocking trouble. Another object of the present invention is to provide a moisture-permeable material which is excellent in transparency and adhesiveness and can be laminated on various substrates by extrusion coating.

[0005]

That is, the present invention comprises a potassium ionomer having a degree of neutralization of 50% or more of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 8 to 30% by weight, The moisture permeability coefficient is 0.02 g / m /
The present invention relates to a moisture-permeable material that is not less than day.

The present invention also provides an unsaturated carboxylic acid content of 8
A hydrophilic compound is blended with an alkali metal ionomer having a neutralization degree of 50% or more of an ethylene / unsaturated carboxylic acid copolymer having a moisture permeability coefficient of 0.02 g /
It relates to a moisture-permeable material having a m / day or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The ionomer used in the present invention is an ionomer of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 8 to 30% by weight. As the unsaturated carboxylic acid of the ethylene / unsaturated carboxylic acid copolymer serving as a base polymer, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride,
Typical examples thereof include itaconic anhydride. Of these, acrylic acid or methacrylic acid is most preferred. In the above-mentioned copolymer, another monomer may be copolymerized as an optional component. The presence of such optional components is effective for imparting flexibility and improving moisture permeability of the ionomer, and specifically, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, and nbutyl acrylate And unsaturated carboxylic esters such as isooctyl acrylate, methyl methacrylate, isobutyl methacrylate, and dimethyl maleate; vinyl esters such as vinyl acetate and vinyl propionate; and carbon monoxide.

The polymerization composition of the ethylene / unsaturated carboxylic acid copolymer is such that the unsaturated carboxylic acid content is 8 to 30.
%, Preferably in the range of 10 to 25% by weight, and the optional copolymer component is in the range of 0 to 40% by weight, particularly 0 to 2% by weight.
A range of 0% by weight is preferred. That is, when a copolymer having an unsaturated carboxylic acid content lower than the above range is used, it is difficult to obtain an ionomer having good moisture permeability.On the other hand, when a copolymer having an unsaturated carboxylic acid content higher than the above range is used, the ionomer of It is not preferable because water resistance and mechanical strength decrease. Further, the optional copolymer component is useful for adjusting flexibility and moisture permeability as described above, but having too much content lowers the mechanical strength or adversely affects blocking. Is not preferred.

[0009] Such copolymers also include 190
C. and a melt flow rate at a load of 2160 g of 0.
05 to 500 g / 10 min, especially 0.1 to 100 g / 1
It is preferable to use one for 0 minutes. When a material having a very high melt flow rate is used, the obtained mechanical strength tends to be insufficient, and when it is too low, it is difficult to obtain an ionomer having good processability. Such an ethylene / unsaturated carboxylic acid copolymer can be obtained by radical copolymerization under high temperature and high pressure.

The ionomer in the first invention is 50 to 100 mol%, preferably 55 to 100 mol%, based on the carboxyl group of the ethylene / unsaturated carboxylic acid copolymer.
It is obtained by neutralization with an amount of potassium ions corresponding to 99 mol%. That is, even if lithium ions or sodium ions are used instead of potassium ions, an ionomer having good moisture permeability cannot be obtained. If the degree of neutralization is lower than the above range, it is difficult to obtain an ionomer having good moisture permeability.

In the second invention, a composition of an alkali metal ionomer of the above-mentioned ethylene / unsaturated carboxylic acid copolymer and a hydrophilic compound is used. Here, the alkali metal ionomer is an ionomer of lithium, sodium, potassium, rubidium, and cesium, and a potassium ionomer is particularly preferable because it is inexpensive and has excellent moisture permeability. The alkali metal ionomer has a degree of neutralization of 50 to 100 mol%, preferably 5 to 100 mol%.
Those having a range of 5 to 99 mol% are used. That is, if an ionomer having a high degree of neutralization is used, a composition having good moisture permeability can be obtained. However, if the degree of neutralization is close to 100 mol%, production by the neutralization method is difficult, and the melt viscosity is generally too high. It becomes difficult to mold.

The ionomer according to the first and second aspects of the present invention has a melt flow rate of 0.05 to 500 g / 10 minutes at 190 ° C. and a load of 2160 g, particularly 0, in consideration of moldability and mechanical strength. .1 to
It is preferable to use one with 100 g / 10 min.

In the second invention, a hydrophilic compound is blended with the alkali metal ionomer. The hydrophilic compound is an organic or inorganic compound, for example, cross-linked polyethylene glycol, polyalkylene oxide, alkylene oxide compounds such as crown ether, ethanol, ethylene glycol, glycerin,
Diglycerin, triglycerin, pentaerythritol, sorbitol, phenol, cresol, naphthol, resorcinol, hydroquinone, 2,4-dihydroxybenzoic acid, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, partial ester of polyhydric alcohol, alkylene of polyhydric alcohol Hydroxyl-containing compounds such as oxide adducts, benzenesulfonic acid, p-hydroxybenzenesulfonic acid, linear alkylbenzenesulfonic acid, sulfonic acid group-containing compounds such as taurine, sodium polyacrylate, sodium polyacrylate crosslinked product, poly Acrylic compounds such as acrylamide, amines such as polyallylamine, aniline, triethanolamine and alkylamine alkylene oxide adducts Sodium alginate, sodium chondroitin sulfate, dextrin, polysaccharides such as cyclodextrin, perchlorate (Li, Na, C
s, K), potassium carbonate, calcium carbonate, potassium sulfate, sodium sulfate, barium titanate, clay, inorganic compounds having crystallization water (such as cadmium sulfate and strontium sulfate), and the like.
Among these, the effect of improving moisture permeability is large, and since the alkali metal ionomer is plasticized without significantly lowering the transparency to significantly improve the extrusion coating processability, the use of an alkylene oxide compound or a hydroxyl group-containing compound is preferred. Especially, the use of polyhydric alcohol, polyethylene glycol or cross-linked polyethylene glycol is most preferred. Of course, two or more of these may be used in combination.

The effective amount of these hydrophilic compounds is as follows:
Although it depends on the type of the ionomer and the type of the ionomer, 1 per 100 parts by weight of the ionomer and the hydrophilic compound is added.
The amount is preferably in the range of from 50 to 50 parts by weight, particularly preferably in the range of from 2 to 25 parts by weight.

Various additives can be added to the moisture-permeable material of the present invention, if necessary. Examples of such additives include antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, pigments, dyes, lubricants, antiblocking agents, antistatic agents, fungicides, antibacterial agents, flame retardants, Flame retardant aids and the like can be mentioned.

The moisture-permeable material according to the first and second inventions has a moisture permeability coefficient of 0.02 g / m / day or more, preferably 0.04 g / m / day or more.
Generally, the thickness is 1 to 100 μm, preferably 5 to 70 μm
It is preferable to use a film having a water resistance of 1000 mmH ₂ O or more in order to exhibit sufficient water resistance. In particular, in the field of diapers, the moisture permeability coefficient is 0.1 g / m2 at the same time.
It is desirable to use one that is at least / day.

When the moisture-permeable material of the present invention is used in the form of a film, it can be used by being laminated on various substrates.
Examples of such a substrate include woven fabric, nonwoven fabric, paper, various synthetic resin films, metal foil such as aluminum foil, and wood. Particularly, in the moisture-permeable material of the second invention in which an alkali metal ionomer and a hydrophilic compound are blended, if a suitable hydrophilic compound is used as described above, it can be easily laminated on these substrates by extrusion coating. Is possible.

Specific examples of uses of the moisture-permeable material of the present invention include sanitary materials such as gathers and back sheets for disposable diapers, sanitary articles, clothing such as coats and sports clothing, packaging materials for foods and flowers, and roofing materials. And building materials such as wall materials and flooring materials, and agricultural materials such as agricultural and horticultural films. If used for these purposes,
Since the film has excellent suitability for high-speed processing, scratch resistance, transparency, adhesiveness, and the like, it is possible to efficiently produce high-quality products.

[0019]

Next, the present invention will be described in more detail by way of examples. In addition, the raw materials and the method of measuring the moisture permeability used in the examples and comparative examples are as follows.

1 Raw Material Ionomer 1: Potassium ionomer of ethylene-methacrylic acid copolymer having a methacrylic acid content of 12.5% by weight (neutralization degree 92%, melt flow rate (MFR) 0.1)
g / 10 minutes) Ionomer 2: potassium ionomer of ethylene / methacrylic acid copolymer having a methacrylic acid content of 15% by weight (neutralization degree: 80%, MFR: 0.1 g / 10 minutes) Ionomer 3: methacrylic acid content: 12.5% by weight LDPE: High-pressure low-density polyethylene (trade name: Mirason 16, MFR 3.7 g / 10 min., Manufactured by Mitsui Chemicals, Inc.). Potassium ionomer of ethylene-methacrylic acid copolymer (neutralization degree: 40%, MFR: 6.9 g / 10 min.) EMAA: Ethylene / methacrylic acid copolymer having a methacrylic acid content of 9% by weight (MFR 2.5 g / 10 minutes) EVA: Ethylene / vinyl acetate copolymer having a vinyl acetate content of 19% by weight (MFR 15 g / 10 minutes) PEG600: Molecular weight 600 polyethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) Crosslinked PEG: Crosslinked polyethylene Alcohol (trade name AQUACALK TQW7 Sumitomo Seika Chemicals Co., Ltd.)

2 Moisture Permeability Coefficient Measurement Method Using a 50 μm film sample, the cup method (JI
S Z0208). Measurement atmosphere: 40 ° C x 90
% RH

3 Optical Measurement Method The haze value of a 50 μm film sample was measured and determined as follows. ：: superior to ionomer (haze value 1 or less) △: comparable to ionomer (haze value 1 to 8) ×: cloudy

[Examples 1 to 5, Comparative Examples 1 to 6] A film having a thickness of 50 μm was prepared from the polymer or polymer composition shown in Table 1 by an inflation method.
The MFR value and the optical properties were measured. Table 1 shows the results.

As is apparent from the comparison between Example 1 and Example 2 and the comparison between Example 4 and Example 5, the moisture permeability is improved by the addition of polyethylene glycol, and the workability is maintained while the transparency is maintained. Is remarkably improved. As is clear from the comparison between Example 1 and Example 3, the addition of the cross-linked polyethylene glycol improves the processability while maintaining transparency, and significantly improves the moisture permeability more than expected. You can see that.

[0025]

[Table 1]

A single screw extruder manufactured by Tanabe Plastic Company (40 m
mφ, L / D = 32), a die width of 470 mm, a resin temperature of 250 ° C., and a line speed of 87 m / min.
When the ionomer composition (MFR 3.7 g / 10 minutes) used in Example 2 was extrusion-coated on an OPP film substrate so as to have a thickness of μm, neck-in and wagging of the laminated film were observed. The neck-in was as small as about 50 mm (25 mm × 2) with respect to the die width of 470 mm. The state of application to the substrate surface was almost constant at about 420 mm, and the trembling width was as small as ± 5 mm or less.

[0027]

According to the present invention, it is possible to provide a moisture-permeable material whose moisture permeability and flexibility can be easily adjusted. Such a moisture-permeable material has excellent mechanical strength, workability, adhesiveness, transparency, blocking resistance, and the like, and can be used for sanitary materials, packaging materials, and various other uses.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4D006 GA01 MA03 MA06 MA31 MA40 MB02 MB16 MB19 MB20 MC22X MC32X MC35 MC36X MC75X MC83 MC89 NA46 NA50 PB12 PC80 4J002 BB231 CH022 EC046 EC056 EH056 EJ016 EJ026 EV236 FD202

Claims (3)

[Claims] An unsaturated carboxylic acid content of 8 to 30% by weight.
A moisture permeable material comprising a potassium ionomer having a degree of neutralization of 50% or more of an ethylene / unsaturated carboxylic acid copolymer, and having a moisture permeability coefficient of 0.02 g / m / day or more. 2. An unsaturated carboxylic acid content of 8 to 30% by weight.
A moisture permeable material comprising a hydrophilic compound blended with an alkali metal ionomer having a neutralization degree of 50% or more of an ethylene / unsaturated carboxylic acid copolymer, and having a moisture permeability coefficient of 0.02 g / m / day or more. . 3. The moisture-permeable material according to claim 2, wherein the hydrophilic compound is an alkylene oxide compound or a hydroxyl group-containing compound.