JPWO2014088065A1 - Moisture permeable film and method for producing the same - Google Patents

Abstract

Provided is a moisture permeable film having excellent liquid permeability while maintaining air permeability, moisture permeability, mechanical strength and practicality. A polyethylene resin composition (A) containing a polyethylene resin having a melting peak temperature of 130 to 150 ° C. and a density of 0.940 to 0.970 g / cm 3, an inorganic filler (B), and a styrenic elastomer (C), It consists of a resin composition in which 1 to 20 parts by mass of the styrene-based elastomer (C) is added to 100 parts by mass of the polyethylene resin composition (A) and the inorganic filler (B), and the oozing area is 5%. Less moisture permeable film.

Description

  The present invention relates to a moisture permeable film and a method for producing the same, and more particularly to a moisture permeable film that can achieve both moisture permeability and liquid resistance and is excellent in air permeability, mechanical strength, and practicality, and a method for producing the film.

  Conventionally, a moisture-permeable film made of a resin composition containing a polyolefin-based resin and an inorganic filler causes interfacial peeling between the resin and the inorganic filler by stretching, and forms innumerable voids (micropores). Provides moisture permeability and breathability. Since these films have innumerable voids formed in the inside thereof, the liquid does not permeate while having high air permeability and moisture permeability. Taking advantage of this feature, it is used in a wide range of products such as disposable paper diapers, sanitary materials such as feminine hygiene products, breathable films, disposable chemical protective clothing, tarpaulins and battery separators.

  Conventionally, the back sheets of disposable diapers and sanitary products are mostly plain white, but in recent years, there are increasing cases in which printing of various color patterns is performed in consideration of design. On the other hand, this type of film has been made thinner and lower in basis weight for the purpose of cost reduction and weight reduction. In this way, when the film is thinned and the basis weight is reduced, the operating tension of the printing machine causes the film to stretch in the machine direction (hereinafter referred to as MD), resulting in defects such as misalignment and deformation of printing pitch, and deterioration of physical properties. There is a problem to do.

  In response to the above problem, the conventional low-density polyethylene was changed to polyolefin with high tensile modulus such as high-density polyethylene and polypropylene, and a method of making the film difficult to stretch by increasing the draw ratio was adopted. However, the texture and texture are reduced. Further, when a large amount of high-density polyethylene with high crystallinity is included, stretching unevenness due to necking frequently occurs, and there is a concern about liquid leakage and deterioration of liquid permeation resistance due to the formation of large voids and pinholes.

  Therefore, in order to obtain a film that is excellent in strength, breathability, moisture permeability and texture / texture and does not cause liquid leakage, it has excellent texture / texture and does not cause stretching unevenness while using high-density polyethylene, polypropylene, etc. Formulation design and manufacturing methods must be taken to form homogeneous voids.

  For the modification of high-density polyethylene, an elastomer such as an olefin-based elastomer is blended, and the elastomer is partially compatible with the high-density polyethylene to reduce the crystallinity and elastic modulus for modification. For example, a porous film disclosed in Japanese Patent No. 3420363 (Patent Document 1) having excellent moisture permeability, flexibility and stretchability is a specific ethylene- (α-olefin) having a low density and a low melting point. The copolymer is produced from a resin composition containing a specific thermoplastic elastomer and an inorganic filler.

Japanese Patent No. 3420363

  However, there are many cases where the effect is not exhibited depending on the type and amount of the elastomer. The porous film of Patent Document 1 is based on a low-density, low-melting ethylene- (α-olefin) copolymer, with emphasis on moisture permeability, flexibility, and stretchability. Therefore, liquid resistance is low, there is a risk of liquid leakage as disposable diapers and sanitary products, and it is inferior in strength and heat resistance, so it cannot be used for moisture permeable waterproof sheets, battery separators, disposable chemical protective clothing, etc. Met.

  The present invention has been made in view of the above problems, and provides a moisture-permeable film having excellent moisture permeability and excellent liquid permeability, which is a contradictory requirement, and excellent in strength and heat resistance. Is an issue.

  In order to solve the above-mentioned problems, the inventors have intensively studied. As a result, the heat resistance and strength are increased using a polyethylene resin composition containing a high-density polyethylene resin having a high melting peak temperature and a high density, and an appropriate compatibility. It has been found that a moisture-permeable film can be obtained by blending a styrene-based elastomer exhibiting properties to achieve both liquid permeation resistance while maintaining moisture permeability and air permeability, and with no risk of liquid leakage.

The present invention obtained from the above findings
A polyethylene resin composition (A) containing a polyethylene resin having a melting peak temperature of 130 to 150 ° C. and a density of 0.940 to 0.970 g / cm ³ , an inorganic filler (B), and a styrenic elastomer (C) The resin composition comprising 1 to 20 parts by mass of the styrene-based elastomer (C) with respect to a total of 100 parts by mass of the polyethylene resin composition (A) and the inorganic filler (B),
It is a moisture-permeable film characterized in that the oozing area is less than 5%.

  The polyethylene resin composition (A) and the inorganic filler (B) of the moisture-permeable film of the present invention are blended at a ratio of (A) :( B) = 60-20 parts by mass: 40-80 parts by mass. It is preferable.

The polyethylene resin composition (A) is a high density polyethylene having a density of 0.940~0.970g / cm ³ (a), linear low density polyethylene having a density of 0.915~0.939g / cm ³ (b) And low density polyethylene (c) having a density of 0.910 to 0.930 g / cm ³ ,
It is preferable to mix | blend in the ratio of said (a) :( b) :( c) = 5-40 mass%: 50-93 mass%: 2-10 mass%.

  The styrene elastomer (C) of the moisture-permeable film of the present invention is a styrene-olefin-styrene block copolymer, and preferably contains 10 to 40% by mass of a styrene component.

Moreover, it is preferable that the basic weight (weight per unit area) of the moisture-permeable film of the present invention is 10 to 50 g / m ² .

Moreover, it is preferable that the moisture permeability of the moisture-permeable film of this invention is 1,000-15,000g / (m < ² > * 24h).

  Moreover, it is preferable that the air permeability of the moisture-permeable film of the present invention is 100 to 10,000 seconds / 100 mL.

  In addition, the moisture permeable film of the present invention preferably has a tensile breaking strength in the machine direction (MD) of 500 gf / 25 mm or more.

  The moisture-permeable film according to the present invention has excellent moisture permeability and air permeability, and is extremely excellent in liquid resistance (liquid barrier property), and has both of these contradictory characteristics. Therefore, there is no risk of liquid leakage when used in a paper diaper or sanitary product, which is preferably used. Furthermore, although it is very light weight, it has mechanical strength, heat resistance, and practical advantages, it can be suitably used for various applications.

It is explanatory drawing of the evaluation method of a oozing area.

Hereinafter, the moisture-permeable film of the present invention will be described in detail.
The moisture-permeable film of the present invention comprises a polyethylene resin composition (A) containing a polyethylene resin having a melting peak temperature of 130 to 150 ° C. and a density of 0.940 to 0.970 g / cm ³ , an inorganic filler (B), Resin composition containing 1 to 20 parts by mass of the styrene elastomer (C) with respect to a total of 100 parts by mass of the polyethylene resin composition (A) and the inorganic filler (B), including the styrene elastomer (C). It consists of things.
While it has liquid permeation resistance with an exudation area of less than 5%, it has a moisture permeability of 1,000 to 15,000 g / (m ² · 24 h) and a high moisture permeability, and has an air permeability of 100 to 10. It has high air permeability at 000 seconds / 100 mL. Furthermore, while the basis weight (weight per unit area) is as light as 10 to 50 g / m ² , the tensile breaking strength in the machine direction (MD) is 500 gf / 25 mm or more, and has heat resistance.

(Components of moisture-permeable film)
The polyethylene resin composition (A) as a raw material of the moisture-permeable film of the present invention has a melting peak temperature of 130 to 150 ° C. and a density of 0.940 to 0.970 g / cm ³ , high density polyethylene (a) The strength and heat resistance are enhanced by using the high-density polyethylene (a).
The polyethylene resin composition (A) used in the present invention contains linear low density polyethylene (b) having appropriate flexibility and strength in the high density polyethylene (a), and further improves the molding processability. It is preferable to add low-density polyethylene (c) produced by a high-pressure polymerization method.

The high-density polyethylene (a), linear low-density polyethylene (b), and low-density polyethylene (c) are ethylene homopolymer and ethylene-propylene, ethylene- (1-butene), ethylene- (1-hexene). , Ethylene- (α-olefin) copolymers such as ethylene- (4-methyl-1-pentene) and ethylene- (1-octene), and polypropylene include propylene homopolymer and propylene-ethylene copolymer. Can be mentioned. These are polymerized using a multi-site catalyst such as a Ziegler type or a Philips type, or a single site catalyst such as a metallocene type, an oxidant, a peroxide or the like as a polymerization initiator.
As described above, the density of the high-density polyethylene (a) is 0.940 to 0.970 g / cm ³ , and preferably 0.945 to 0.965 g / cm ³ . The density of the linear low density polyethylene (b) is preferably 0.915 to 0.939 g / cm ³ , and the density of the low density polyethylene (c) is preferably 0.910 to 0.930 g / cm ³ .
The melt mass flow rate (hereinafter referred to as MFR. 190 ° C., 2.16 kgf) is preferably 0.1 to 20 g / 10 min, more preferably 0.5 to 5 g / 10 min. When the MFR is 0.1 g / 10 min or more, the formability of the thin film can be sufficiently maintained, and when the MFR is 20 g / 10 min or less, sufficient strength can be obtained.
The melting point of the high density polyethylene (a) is 130 to 150 ° C, preferably 130 to 140 ° C. Moreover, it is preferable that melting | fusing point of linear low density polyethylene (b) is 100-130 degreeC, and melting | fusing point of low density polyethylene (c) is 100-120 degreeC.

Specifically, the polyethylene resin composition (A) is a high density polyethylene having a density of 0.940~0.970g / cm ³ (a), linear low density density 0.915~0.939g / cm ³ Including polyethylene (b) and low density polyethylene (c) having a density of 0.910 to 0.930 g / cm ³ , wherein (a) :( b) :( c) = 5 to 40% by mass: 50 to 93 It is preferable to set it as the mixture of mass%: 2-10 mass%.

  Examples of the inorganic filler (B) include fine particles such as calcium carbonate, calcium sulfate, barium carbonate, barium sulfate, and titanium oxide. Of these, calcium carbonate and barium sulfate are preferred. The average particle size is preferably from 0.1 to 10 μm, more preferably from 0.3 to 5 μm, still more preferably from 0.5 to 3 μm. An average particle size of 0.1 μm or more is preferable because poor dispersion and secondary aggregation of the inorganic filler (B) can be suppressed and the inorganic filler (B) can be uniformly dispersed. On the other hand, when the average particle diameter is 10 μm or less, the generation of large voids is suppressed during the thinning, and sufficient strength and liquid permeation resistance can be obtained. Further, for the purpose of improving the dispersibility / mixability with the resin, it is preferable to coat the fine particles with fatty acid, fatty acid ester, etc. in advance so that the surface of the fine particles can be easily blended with the resin.

About the blend ratio (A) :( B) of the polyethylene resin composition (A) and the inorganic filler (B), (A) :( B) = 60-20 parts by mass: 40-80 parts by mass Is preferred.
More preferably, it is (A) :( B) = 55-25 mass parts: 45-75 mass parts, More preferably, it is 50-30 mass parts: 50-70 mass parts. When the blending ratio (A) :( B) is within the above range, both moisture permeability and air permeability and liquid permeation resistance can be sufficiently achieved.

As the styrene elastomer (C), styrene-olefin (SEP, SEBC, etc.), styrene-olefin-styrene (SEPS, SEBS, etc.), styrene-diene (SIS, SBS, etc.), hydrogenated styrene-diene, etc. Examples include elastomers containing styrene blocks (HSIS, HSBR, etc.). Of these, a styrene-olefin-styrene block copolymer is preferred from the viewpoint of dispersibility and compatibility with high-density polyethylene and linear low-density polyethylene.
Commercially available products include “Hibler” and “Septon” manufactured by Kuraray Co., Ltd., “Tough Tech” and “Tuff Plain” manufactured by Asahi Kasei Chemicals Corporation, “Dynalon” manufactured by JSR Corporation, and Kraton Performance Polymers Inc. “KRATON G”, “KRATON D” manufactured by PolyOne Corporation, “OnFlex S” manufactured by PolyOne Corporation, and the like.

As a selection criterion for the styrene-based elastomer (C), it is preferable that the styrene-based elastomer (C) has an appropriate compatibility with the polyethylene resin composition (A). If the compatibility between the polyethylene resin composition (A) and the styrene elastomer (C) is too low, the styrene elastomer (C) takes a layered, cylindrical or large domain (dispersed phase) structure, Stretching is hindered, and the problem to be solved by the invention cannot be solved. On the other hand, if the compatibility between the polyethylene resin composition (A) and the styrene elastomer (C) is too high, the styrene elastomer (C) reduces the crystallinity and elastic modulus of the polyethylene resin composition (A). The tensile strength of the film is greatly reduced.
From the viewpoint of appropriate compatibility, the styrene component in the styrene elastomer (C) is preferably 10 to 40% by mass, and more preferably 20 to 40% by mass.

  In order to uniformly knead and disperse the polyethylene resin composition (A) and the styrene elastomer (C), the viscosity of the styrene elastomer (C) is a polyethylene resin in the molding temperature and shear rate range of the resin composition. The thing of the same grade as the viscosity of a composition (A) is preferable. The viscosity of the styrene-based elastomer (C) is preferably MFR and is in the range of 0.1 to 10 g / 10 min (230 ° C., 2.16 kgf).

  As described above, the content of the styrene-based elastomer (C) is 1 to 20 parts by mass, preferably 2 with respect to 100 parts by mass in total of the polyethylene resin composition (A) and the inorganic filler (B). -15 parts by mass. This blending amount is important, and when the content of the styrenic elastomer (C) is 1 part by mass or more, the moisture permeability, air permeability and liquid permeation resistance can be compatible. On the other hand, the mechanical strength is sufficiently maintained by setting it to 20 parts by mass or less.

  You may add another additive as needed. Specifically, higher fatty acid, higher fatty acid ester, higher fatty acid amide, metal soap, higher alcohol, petrolatum, paraffin wax, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, castor oil, hydrogenated castor oil And additives such as hardened castor oil, dehydrated castor oil, aromatic esters, aromatic amides and polyethers, plasticizers such as low molecular weight polymers (oligomers) such as polyester, lubricants, and additives that favorably disperse the inorganic filler (B). . Of the additives, hardened castor oil is preferably used, and the blended amount of the hardened castor oil is preferably 1 to 5% by weight, more preferably 100% by weight based on the total of (A), (B) and (C). Is 3-4 mass%.

  In addition to the above additives, compatibilizers, processing aids, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, antiblocking agents, antifogging agents, matting agents, depending on the intended use , Surfactants, antibacterial agents, deodorants, antistatic agents, water repellents, oil repellents, radiation shielding agents, colorants and pigments may be added to or applied to the resin composition. Among the additives, a heat stabilizer is preferably used, and the blending amount of the heat stabilizer is 0.1 to 1% by mass with respect to a total of 100% by mass of the (A), (B), and (C). preferable.

(Manufacturing method of moisture-permeable film)
The moisture-permeable film of the present invention is obtained by melt-kneading the resin composition, extrusion-molding it by a T-die method or an inflation method, and stretching it at least once in a temperature range of 15 to 100 ° C. in the machine direction (MD). And manufactured.
Specifically, the polyethylene resin composition (A), the inorganic filler (B), and the styrenic elastomer (C) are mixed and dispersed by a mixer such as a tumbler, super mixer, Henschel mixer or the like. Thereafter, it is melt-kneaded with a uniaxial or biaxial kneader or an extruder to form pellets. Alternatively, pellets can be obtained by directly feeding raw materials into a hopper or side feeder without using a mixer. At that time, it is melt-kneaded at a melting point or higher of the polyethylene resin composition (A), preferably from a melting point + 30 ° C. to less than the decomposition temperature of the resin composition. Next, the pellets are melted and formed into a film using a known molding method such as an extrusion molding machine equipped with a T die and an inflation molding machine equipped with a circular die. Depending on the case, it is also possible to directly form a film without once pelletizing.

  The formed unstretched film is stretched at least once in the machine direction (MD) by a stretching method such as a known roll method, tenter method, or stretch method. It is preferable that the temperature of the stretching roll is 15 to 100 ° C., and the stretching ratio is 1.5 to 5.0 times in total.

As a measure against heat shrinkage of the moisture-permeable film, heat setting may be performed after stretching. Here, heat setting refers to applying heat to the moisture-permeable film in advance after the stretching step to intentionally heat-shrink the moisture-permeable film to suppress shrinkage of the moisture-permeable film. Examples of the heat setting method include a method in which the draw ratio (ratio of winding side roll speed / unwinding side roll speed) is made negative while heating the stretched moisture permeable film with a heated roll (annealing roll). . Here, if the heat setting temperature is too low, the heat shrinkage rate of the moisture permeable film is increased, and if the heat setting temperature is too high, a trouble occurs in which the moisture permeable film sticks to the roll and winds. Considering the above points, the heat setting temperature is preferably 70 to 120 ° C.
On the other hand, if the negative draw ratio is too small, the heat fixation is not sufficiently performed, and if it is too large, the film sag between the rolls, causing production trouble. Therefore, −10 to −20% is preferable. Further, these rolls are preferably made of metal having a large heat capacity and a smooth chrome-plated surface.

(Physical properties of moisture-permeable film)
As mentioned above, the oozing area of the moisture permeable film is less than 5%, preferably less than 2%. The oozing area is measured by the method described later.
A oozing area of less than 5% means having sufficient liquid permeation resistance. When the moisture-permeable film of the present invention is used for a back sheet such as a disposable diaper or a feminine sanitary product, it is essential that water, urine or menstrual blood does not leak or exude on the back surface of the moisture-permeable film. Liquidity is an important evaluation item. This can be achieved by adding a styrene-based elastomer (C) to the polyethylene resin composition (A) and the inorganic filler (B) so that the oozing area is less than 5%.

As described above, the basis weight of the moisture-permeable film is preferably 10 to 50 g / m ² , more preferably 15 to 40 g / m ² , and still more preferably 15 to 30 g / m ² . When the basis weight is within the above range, it is possible to sufficiently achieve both air permeability, comfort and liquid permeation resistance. The measuring method of this basic weight is mentioned later.

As described above, the moisture permeability of the moisture permeable film is preferably 1,000 to 15,000 g / (m ² · 24 h), more preferably 2,000 to 10,000 g / (m ² · 24 h), and still more preferably. 3,000 to 10,000 g / (m ² · 24 h). When the moisture permeability is 15,000 g / (m ² · 24 h) or less, it is suggested that the film has water resistance and liquid resistance. In addition, the moisture permeability is 1,000 g / (m ² · 24h) or more, which suggests that the hole has sufficient communication and is comfortable to wear. A method for measuring the moisture permeability will be described later.

  As described above, the air permeability of the moisture-permeable film is preferably 100 to 10,000 seconds / 100 mL, more preferably 200 to 3,000 seconds / 100 mL, and still more preferably 300 to 2,000 seconds / 100 mL. An air permeability of 10,000 seconds / 100 mL or less suggests that the pores have sufficient communication. Moreover, when the air permeability is 100 seconds / 100 mL or more, the effects of water resistance and liquid resistance can be sufficiently obtained. A method for measuring the air permeability will be described later.

As described above, the strength of the moisture permeable film is preferably 500 gf / 25 mm or more, more preferably 700 gf / 25 mm or more in the machine direction (MD).
Sufficient mechanical strength can be ensured by being 500 gf / 25 mm or more. The upper limit is not particularly limited, but is preferably 3000 gf / 25 mm or less in view of stretchability.

It is good also as a film laminated body which laminated | stacked multiple moisture-permeable films of this invention. Moreover, it is good also as a film laminated body which laminated | stacked the moisture-permeable film of this invention with the other film. In any laminated body, the laminated body as a whole has liquid permeability resistance of less than 5% and moisture permeability of 1,000 to 15,000 g / (m ² · 24 h). preferable.

  Examples of the present invention will be described below, but the present invention is not limited thereto. Table 1 shows the raw materials used in the examples and comparative examples, and Table 2 shows the compounding amounts of the examples and comparative examples.

  The raw materials of Examples 1 and 2 and Comparative Examples 1 to 3 described in Table 1 above were mixed for 5 minutes with a Henschel mixer, then melt-kneaded with a φ80 mm co-directional twin-screw extruder set at 180 ° C., and once pelletized did.

Thereafter, an unstretched film was obtained using the φ65 mm single screw extruder for the front and back layers, the φ90 mm single screw extruder for the intermediate layer, and a φ300 mm inflation die under the following conditions.
Cylinder temperature: 150 ° C (C1), 170 ° C (C2), 190 ° C (after C3)
Conduit temperature: 190 ° C
Inflation die temperature: 190 ° C
Pickup speed: 46m / min
Unstretched film thickness: 50-60 μm

Subsequently, these films were longitudinally stretched with a roll longitudinal stretching machine under the following conditions.
Stretching temperature: 25 to 70 ° C., stretching ratio (total): 2.60 times

  In Example 1 and Example 2, the blending ratio of the hardened castor oil and heat stabilizer as additives is changed. Moreover, none of Comparative Examples 1 to 3 contains a styrene elastomer, and Comparative Example 1 and Comparative Example 2 have different stretching temperatures.

  The produced moisture permeable films of Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated by the following methods. Table 3 shows the evaluation results of Examples and Comparative Examples.

[Evaluation and measurement method]
(1) Judgment of texture and texture The moisture permeable film was judged by tactile sensation.
◎: High flexibility and good touch ○: High flexibility △: Poor flexibility ×: Poor flexibility and poor texture (2) Basis weight (g / m ² )
After collecting a sample [MD: 250 mm, TD: 200 mm] from the moisture-permeable film, the weight measurement (g) was performed, and the numerical value was multiplied by 20 to obtain the basis weight.
(3) Air permeability (sec / 100mL)
Ten points were randomly sampled using an Oken type air permeability measuring device according to the method defined in JIS P8117 (Gurley tester method), and the average value was calculated.
(4) Moisture permeability (g / (m ² · 24h))
The moisture permeability conforms to JIS Z0208 (cup method). The measurement was performed under the conditions of a temperature of 40 ° C., a relative humidity of 90%, and a calcium chloride content of 15 g. Two points were randomly collected and the average value was calculated.
(5) Bleeding area (liquid permeation resistance)
The preparation of the test liquid and the measurement of the oozing area were performed in a constant temperature and humidity room adjusted to a temperature of 23 ° C. and a relative humidity of 50%.
As test solutions, 99.0 parts by mass of distilled water, 1.0 part by mass of a cationic surfactant (manufactured by NOF Corporation, Elegan 263-40), and 0 of red No. 40 pigment (manufactured by Wako Pure Chemical Industries, Allura Red) .30 parts by mass was gradually added and stirred for 1 hour until evenly dissolved and dispersed.
As shown in FIG. 1, the exudation area was evaluated on a filter paper (FILTER PAPER No. 2 diameter 70 mm manufactured by Advantech Co., Ltd.) on a 100 mm × 100 mm square moisture-permeable film, 70 mm × 70 mm square. The moisture retention sheet was stacked, and 2.0 mL of the test solution was gently dropped with a dropper on the center of the moisture retention sheet. After dripping, a resin plate (diameter 60 mm × thickness 5 mm) was placed on the moisture retention sheet, and a weight of 2 kg was placed thereon and left for 30 minutes. The test liquid oozes out from the back surface of the moisture-permeable film, and the area of the filter paper colored in red (exuded) is measured, and the ratio of the area in the entire pressurized filter paper is calculated. The following evaluation was performed.
A: Exudation area is less than 2%
○: Exudation area is 2% or more and less than 5%
Δ: Exudation area is 5% or more and less than 15%
X: Exudation area is 15% or more
(6) Tensile breaking strength in the machine direction (MD) (gf / 25 mm)
Conforms to JIS K7127. Measurement was performed three times at a test width of 25 mm and a tensile speed of 200 m / min, and the average value was obtained.
(7) ASTM F1671 Virus Barrier Test Based on ASTM F1671-07 B method, Bacteriophage Phi-X174 was used as a test virus and Escherichia coli bacteria C was used as a host bacterium. In addition, the virus barrier test was done using the test liquid which surface tension adjusted to 42 mN / m.
The measurement was performed three times, and if the number of phages (PFU / mL) representing the amount of virus permeation was all less than 1, it was considered that there was no virus permeation and was judged as “pass”.
Conducted at Kaken Test Center Osaka Office.

  There is a correlation between the oozing area, which is an indicator of liquid permeation resistance, and the virus barrier properties obtained by the virus barrier test, and the moisture permeable film of the present invention has good liquid permeation resistance (exudation of test liquid). By having (suppression), it also has good virus barrier properties (suppression of virus transmission).

  In Example 1 and Example 2, the oozing area, which is an index of liquid permeation resistance, passed with less than 2%, but Comparative Examples 1 and 2 could not clear less than 5% and were Δ. The comparative example 3 was 15% or more and x. And Comparative Example 2 failed the virus barrier test. Examples 1 and 2 were rich in stretchability and had good texture and texture. The air permeability and moisture permeability were also excellent, and as described above, the liquid resistance was very good, and it passed the ASTM F1671 virus barrier test.

  In Comparative Examples 1 and 2 in which the styrene elastomer (C) was not added, necking / stretching unevenness specific to stretching of the polyethylene resin / inorganic filler film appeared, and the surface condition was poor. Since liquid leakage occurred from uneven stretching and fine pinholes, the liquid permeation resistance was poor, and Comparative Example 2 failed the ASTM F1671 virus barrier test. Moreover, since the high density polyethylene resin was not added in Comparative Example 3, both the texture and the tensile strength were good, but the liquid permeation resistance was much worse than the others, and the evaluation was x. For this reason, Comparative Example 3 did not carry out the ASTM F1671 virus barrier test.

  The moisture-permeable film of the present invention has excellent liquid resistance and barrier properties while maintaining air permeability, moisture permeability, mechanical strength, and practicality while being very lightweight. Therefore, sanitary materials such as disposable paper diapers, feminine hygiene products, breathable films, tarpaulins, disposable chemical protective clothing, work clothes, jumpers, jackets, medical clothing, masks, covers, drapes, sheets and wraps, and It can be suitably used for a wide range of products such as battery separators.

Claims (11)

A polyethylene resin composition (A) containing a polyethylene resin having a melting peak temperature of 130 to 150 ° C. and a density of 0.940 to 0.970 g / cm ³ , an inorganic filler (B), and a styrenic elastomer (C) ,
It consists of a resin composition in which 1 to 20 parts by mass of the styrene-based elastomer (C) is added to 100 parts by mass of the polyethylene resin composition (A) and the inorganic filler (B).
A moisture-permeable film having a oozing area of less than 5%.   The said polyethylene resin composition (A) and an inorganic filler (B) are mix | blended in the ratio of (A) :( B) = 60-20 mass parts: 40-80 mass parts. Moisture permeable film. The polyethylene resin composition (A) is a high density polyethylene having a density of 0.940~0.970g / cm ³ (a), linear low density polyethylene having a density of 0.915~0.939g / cm ³ (b) And low density polyethylene (c) having a density of 0.910 to 0.930 g / cm ³ ,
The moisture permeable film of Claim 1 or Claim 2 mix | blended in the ratio of said (a) :( b) :( c) = 5-40 mass%: 50-93 mass%: 2-10 mass%. .   The moisture-permeable film according to any one of claims 1 to 3, wherein the styrene-based elastomer (C) is a styrene-olefin-styrene block copolymer and contains 10 to 40% by mass of a styrene component. Breathable film according to any one of claims 1 to 4 basis weight of 10 to 50 g / m ^2. The moisture-permeable film according to any one of claims 1 to 5, which has a moisture permeability of 1,000 to 15,000 g / (m ² · 24h).   The moisture-permeable film according to any one of claims 1 to 6, wherein the air permeability is 100 to 10,000 seconds / 100 mL.   The moisture-permeable film according to any one of claims 1 to 7, wherein a tensile breaking strength in a machine direction (MD) is 500 gf / 25 mm or more.   A film laminate in which a plurality of moisture permeable films according to any one of claims 1 to 8 are laminated, or the moisture permeable film is laminated with another film. A method for producing a moisture-permeable film according to any one of claims 1 to 8,
After melt-kneading the resin composition containing the components (A), (B), and (C), the film is extruded by the T-die method or the inflation method, and in the temperature range of 15 to 100 ° C. in the machine direction (MD), A method for producing a moisture-permeable film, which is produced by stretching at least once.   An article of clothing selected from jumpers, jackets, work clothes, protective clothing and surgical clothing, masks, covers, drapes, sheets and wraps using the film laminate of claim 9.

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