JP2019162735A - Moisture-permeable film and package - Google Patents

Abstract

To provide a moisture-permeable film excellent in continuous film-forming properties and appearance and capable of highly controlling moisture permeability.SOLUTION: A moisture-permeable film 10 of the present invention includes: a biaxially oriented film layer (A) containing a thermoplastic resin and at least one filler selected from organic fillers and inorganic fillers; and a surface resin layer (B) provided on at least one surface of the biaxially oriented film layer (A). The total thickness of the surface resin layer (B) is 10 μm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a moisture permeable film and a package.

As the moisture permeable film, a film formed of a resin composition containing a thermoplastic resin and a filler is known.
As a technique regarding such a moisture-permeable film, for example, one described in Patent Document 1 (Japanese Patent Laid-Open No. 2017-31293) can be cited.

In Patent Document 1, 25 to 75 parts by mass of the polyethylene resin (A), 75 to 25 parts by mass of the inorganic filler (B), and 100 parts by mass of the total amount of the above (A) and (B). A breathable film comprising a resin composition containing 0.5 to 5 parts by mass of an ester plasticizer (C), wherein the resin composition is further melted by heating to form voids in the breathable film. The air-blocking agent (D) that partially occludes is contained in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the total amount of (A) and (B), and the air permeability is 1,000 to 45,000. A breathable film characterized in that the rate of increase in air permeability by heat treatment at 90 ° C. for 30 minutes at a second / 100 mL is 1.5 to 5.0.
In Patent Document 1, a breathable film having the above-described configuration has a function of increasing the air permeability when heated, and a sanitary material sheet, protective clothing, work clothes, a desiccant, and a hygroscopic storage bag. It is described that it can be suitably used.

JP 2017-31293 A

According to the study by the present inventors, a moisture-permeable film formed from a resin composition containing a thermoplastic resin and a filler has a problem of sticking to a chill roll or roll contamination when continuously formed. It was found that the film was inferior in continuous film-forming property and appearance.
Furthermore, a moisture-permeable film formed of a resin composition containing a thermoplastic resin and a filler has been difficult to highly control the level of moisture permeability while maintaining basic properties such as mechanical properties.

  The present invention has been made in view of the above circumstances, and provides a moisture-permeable film that is excellent in continuous film-forming properties and appearance and capable of highly controlling moisture permeability.

  The present inventors diligently studied to solve the above problems. As a result, by providing a resin layer having a total thickness of 10 μm or less on the surface of the biaxially stretched film layer containing the thermoplastic resin and filler, the total of the above resin layers can be maintained while maintaining good continuous film formability and appearance. The inventors have found that moisture permeability can be controlled to a high degree by the thickness, and have reached the present invention.

  That is, according to this invention, the moisture-permeable film and package shown below are provided.

[1]
A biaxially stretched film layer (A) comprising a thermoplastic resin and at least one filler selected from organic fillers and inorganic fillers;
A surface resin layer (B) provided on at least one surface of the biaxially stretched film layer (A),
A moisture-permeable film in which the total thickness of the surface resin layer (B) is 10 μm or less.
[2]
In the moisture-permeable film as described in [1] above,
Moisture permeable film in which the content of the filler in the biaxially stretched film layer (A) is 40% by mass or more and 70% by mass or less when the total amount of the biaxially stretched film layer (A) is 100% by mass. .
[3]
In the moisture-permeable film as described in [1] or [2] above,
The moisture-permeable film in which the thermoplastic resin contains a polyolefin resin.
[4]
In the moisture-permeable film as described in [3] above,
A moisture permeable film in which the polyolefin resin contains at least one selected from polyethylene resins and polypropylene resins.
[5]
In the moisture-permeable film as described in any one of the above [1] to [4],
The biaxially stretched film layer (A) is a moisture permeable film having vents on the surface.
[6]
In the moisture-permeable film as described in any one of the above [1] to [5],
The filler is calcium carbonate, calcium sulfate, barium carbonate, barium sulfate, titanium oxide, magnesium hydroxide, magnesium carbonate, aluminum hydroxide, zinc oxide, magnesium oxide, silica, potassium titanate, calcium sulfite, calcium silicate, wax. A moisture-permeable film comprising one or more selected from lastite, talc, mica, clay, kaolinite, montmorillonite, hydrotalcite, polystyrene resin particles and poly (meth) acrylic resin particles.
[7]
In the moisture-permeable film as described in any one of the above [1] to [6],
A moisture-permeable film having a water vapor permeability of 20 g / (m ² · 24 h) or more at 40 ° C. and 90% RH.
[8]
In the moisture-permeable film according to any one of the above [1] to [7],
The moisture permeable film in which the surface resin layer (B) contains a polyolefin resin.
[9]
In the moisture-permeable film as described in [8] above,
The moisture permeable film in which the polyolefin resin in the surface resin layer (B) contains at least one selected from polyethylene resins and polypropylene resins.
[10]
In the moisture-permeable film as described in any one of the above [1] to [9],
Hygiene products, medical products, healthcare products, filter products, geotextile products, agricultural products, horticultural products, clothing, footwear products, bag products, household products, industrial products, packaging products, construction products and structures A moisture-permeable film used for any one selected from the group consisting of products for medical use.
[11]
A package using the moisture-permeable film according to any one of [1] to [9].

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in continuous film forming property and an external appearance, the moisture-permeable film which can control moisture permeability highly can be provided.

It is sectional drawing which showed typically an example of the structure of the moisture-permeable film of embodiment which concerns on this invention. It is sectional drawing which showed typically an example of the structure of the moisture-permeable film of embodiment which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the figure is a schematic diagram and does not match the actual dimensional ratio. In addition, "-" between the numbers in a sentence represents the following from the above, unless there is particular notice.

<Moisture permeable film>
1 and 2 are cross-sectional views schematically showing an example of the structure of the moisture-permeable film 10 according to the embodiment of the present invention.
The moisture-permeable film 10 according to the present embodiment includes a biaxially stretched film layer (A) including a thermoplastic resin and at least one filler selected from an organic filler and an inorganic filler, and the biaxially stretched film layer ( A surface resin layer (B) provided on at least one surface of A), and the total thickness of the surface resin layer (B) is 10 μm or less.

As described above, as a moisture permeable film, a film formed of a resin composition containing a thermoplastic resin and a filler is known. According to the study by the present inventors, a moisture-permeable film formed from a resin composition containing a thermoplastic resin and a filler has a problem of sticking to a chill roll or roll contamination when continuously formed. It was found that the film was inferior in continuous film-forming property and appearance. Furthermore, a moisture-permeable film formed of a resin composition containing a thermoplastic resin and a filler has been difficult to highly control the level of moisture permeability while maintaining basic properties such as mechanical properties.
The present inventors diligently studied to solve the above problems. As a result, by providing the surface resin layer (B) whose total thickness is controlled to 10 μm or less on the surface of the biaxially stretched film layer (A) containing the thermoplastic resin and filler, the continuous film forming property and appearance are good. It was found that the moisture permeability can be highly controlled by the total thickness of the surface resin layer (B). In particular, the moisture-permeable film 10 according to the present embodiment can control the water vapor permeability and the like in stages by controlling the total thickness of the surface resin layer (B) in stages. Therefore, by controlling the total thickness of the surface resin layer (B), it is possible to easily obtain the moisture permeable film 10 having a desired water vapor permeability.
That is, according to the present embodiment, it is possible to provide a moisture permeable film 10 that is excellent in continuous film-forming properties and appearance and capable of highly controlling moisture permeability.

In the moisture-permeable film 10 according to the present embodiment, the water vapor permeability at 40 ° C. and 90% RH is measured by the following method from the viewpoint of stably obtaining the moisture-permeable film 10 or the package excellent in moisture permeability. Is preferably 20 g / (m ² · 24 h) or more, more preferably 30 g / (m ² · 24 h) or more, still more preferably 50 g / (m ² · 24 h) or more, 100 g / It is particularly preferable that it is not less than (m ² · 24h).
(Measuring method)
The moisture permeable film 10 according to the present embodiment is folded and heat sealed on two sides to form a bag. Then, calcium chloride is added as the contents. Next, the other side is heat-sealed to produce a bag so that the surface area becomes 0.01 m ² . Next, the obtained bag is stored for 1 hour under the conditions of 40 ° C. and humidity 90% RH. The weight of calcium chloride before and after storage is measured, and the water vapor permeability (g / (m ² · 24h)) is calculated from the difference.
Such water vapor permeability is, for example, the content of filler contained in the biaxially stretched film layer (A), the thickness and stretch ratio of the biaxially stretched film layer (A), the total thickness of the surface resin layer (B), and the like. This can be achieved by adjusting. In particular, the moisture permeable film 10 according to the present embodiment is characterized by controlling the total thickness of the surface resin layer (B) to characterize basic characteristics such as mechanical properties of the moisture permeable film 10 ( Water vapor permeability can be controlled at a high level without changing the configuration of A). That is, according to the moisture permeable film 10 according to the present embodiment, it is possible to highly control the moisture permeability level while maintaining basic characteristics such as mechanical characteristics.

The thickness of the moisture permeable film 10 according to the present embodiment is not particularly limited, but can be arbitrarily set according to desired purposes such as water vapor permeability, cost, mechanical properties, lightness, etc. For example, they are 10 micrometers or more and 500 micrometers or less, Preferably they are 15 micrometers or more and 400 micrometers or less, More preferably, they are 20 micrometers or more and 300 micrometers or less.
When the thickness of the moisture permeable film is within the above range, the balance of moisture permeability, breathability, bag-making property, mechanical properties, handleability, appearance, moldability, light weight, cost, etc. is more excellent.

  Hereinafter, each layer which comprises a moisture-permeable film is demonstrated.

[Biaxially stretched film layer (A)]
The biaxially stretched film layer (A) according to this embodiment is composed of, for example, a resin composition (A) that includes a thermoplastic resin and at least one filler selected from organic fillers and inorganic fillers. It is formed by biaxially stretching a stretched film layer.

  The biaxially stretched film layer (A) according to the present embodiment may be a single layer or a structure in which a plurality of layers composed of the resin composition (A) are laminated, but is biaxially stretched. It is necessary.

  In the moisture-permeable film 10 according to the present embodiment, the ratio of the thickness of the biaxially stretched film layer (A) to the entire thickness of the moisture-permeable film 10 is preferably 0.50 or more and 0.998 or less, and more Preferably they are 0.60 or more and 0.99 or less, More preferably, they are 0.70 or more and 0.98 or less, Especially preferably, they are 0.75 or more and 0.98 or less.

In the moisture-permeable film 10 according to the present embodiment, the biaxially stretched film layer (A) preferably has air holes on the surface. Thereby, the moisture permeability and breathability of a moisture-permeable film can be improved further. Here, the air holes are formed on the surface of the moisture-permeable film after peeling the surface resin layer (B) from the surface of the biaxially stretched film layer (A) (that is, the surface of the biaxially stretched film layer (A)). This can be confirmed by observing. The maximum hole diameter of the vent hole is, for example, 5 μm or more and 50 μm or less. Here, the maximum hole diameter means the maximum value of the hole diameter of one ventilation hole.
Such a vent can be formed, for example, by adjusting the content ratio of the filler contained in the biaxially stretched film layer (A), the thickness of the biaxially stretched film layer (A), the stretch ratio, and the like.

(Resin composition (A))
The resin composition (A) according to the present embodiment includes a thermoplastic resin and a filler.
From the viewpoint of improving the moisture permeability and breathability of the moisture permeable film 10, the lower limit value of the filler content contained in the resin composition (A), that is, the biaxially stretched film layer (A) according to the present embodiment is biaxial. When the whole stretched film layer (A) is 100% by mass, it is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, and particularly preferably 60% by mass. % Or more.
In addition, the upper limit value of the filler content contained in the resin composition (A), that is, the biaxially stretched film layer (A) according to the present embodiment is a viewpoint of improving the moldability and mechanical properties of the moisture permeable film 10. Therefore, when the total amount of the biaxially stretched film layer (A) is 100% by mass, it is preferably 70% by mass or less.

  When the total content of the thermoplastic resin and filler contained in the resin composition (A), that is, the biaxially stretched film layer (A) according to the present embodiment is 100% by mass of the entire resin composition (A). Preferably, it is 50 mass% or more and 100 mass% or less, More preferably, it is 70 mass% or more and 100 mass% or less, More preferably, it is 90 mass% or more and 100 mass% or less, Most preferably, it is 95 mass% or more and 100 mass% or less. Thereby, the balance of moisture permeability, air permeability, mechanical properties, handleability, appearance, moldability, and the like can be further improved.

(Thermoplastic resin)
Although it does not specifically limit as a thermoplastic resin used for a biaxially stretched film layer (A), For example, polyacrylic resins, such as polyolefin resin, polymethacrylic resin, such as polymethylmethacrylate resin, polymethylacrylate resin, etc. , Polystyrene resins, polyvinyl acetal resins, polyvinyl butyral resins, polyvinyl formal resins, polymethylpentene resins, polycarbonate resins, polyether ether ketone resins, polyether ketone resins and other polyether resins, polyester resins, polyamide resins, polyamides Imide resin, polyimide resin, polyetherimide resin, styrene elastomer, polyolefin elastomer, polyurethane elastomer, polyester elastomer, polyamide elastomer, nor Lunene resin, polytetrafluoroethylene resin, ethylenetetrafluoroethylene copolymer, polyvinylidene fluoride resin, polyvinyl fluoride resin, thermoplastic polyimide resin, polyvinylidene chloride resin, polyvinyl chloride resin, polyvinyl acetate resin, polysulfone resin, polyphenylene oxide Examples thereof include polyphenylene resins such as resins and polyphenylene sulfide resins, polysulfone resins, polylactic acid resins, polyethersulfone resins, polyacrylonitrile resins, and styrene-acrylonitrile copolymer resins.
Among these, polyolefin resins are preferable from the viewpoint of excellent balance of moisture permeability, breathability, mechanical properties, handleability, appearance, lightness, price, moldability, and the like. These thermoplastic resins may be used individually by 1 type, and may be used in combination of 2 or more types.

(Polyolefin resin)
Examples of the polyolefin resin used for the biaxially stretched film layer (A) include single weights of α-olefins such as ethylene, propylene, butene-1, hexene-1, 4-methyl-pentene-1, and octene-1. High-density low-density polyethylene; Linear low-density polyethylene (LLDPE); High-density polyethylene; Polypropylene; Random copolymer of propylene and α-olefin having 2 to 10 carbon atoms; Ethylene / acetic acid Vinyl copolymer (EVA); ionomer resin and the like. These polyolefin resin may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, at least one selected from polyethylene resins and polypropylene resins is preferable, and polypropylene resins are more preferable.

(Polyethylene resin)
Examples of the polyethylene resin used for the biaxially stretched film layer (A) include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and ultrahigh molecular weight polyethylene. Among these, low density polyethylene and linear low density polyethylene are preferable, and linear low density polyethylene is more preferable. One type of polyethylene may be used, or two or more types may be used in combination.

  The melting point of the polyethylene resin according to this embodiment is preferably 95 ° C. or higher and 135 ° C. or lower, more preferably, from the viewpoint of further improving the balance of heat resistance, mechanical properties, rigidity, fluidity, moldability, and the like. It exists in the range of 100 degreeC or more and 130 degrees C or less.

  In accordance with ASTM D1238, the melt flow rate (MFR) of the polyethylene resin according to this embodiment measured at 190 ° C. and a load of 2.16 kg is preferably 0.5 g from the viewpoint of fluidity and moldability. / 10 min or more, more preferably 1 g / 10 min or more, further preferably 2 g / 10 min or more, and from the viewpoint of further stabilizing the moldability, preferably 30 g / 10 min or less, more preferably 20 g / 10 min. Hereinafter, it is more preferably 10 g / 10 min or less.

  The manufacturing method of the polyethylene-type resin which concerns on this embodiment is not specifically limited, It can manufacture by a well-known method. A commercially available polyethylene resin may be used.

(Polypropylene resin)
Examples of the polypropylene resin used for the biaxially stretched film layer (A) include homopolypropylene, a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like can be mentioned. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable, and ethylene is more preferable. These α-olefins may form a random copolymer with propylene, or may form a block copolymer. The content of the structural unit derived from ethylene or an α-olefin having 4 to 20 carbon atoms is preferably 5 mol% or less, preferably 2 mol% or less, when the entire polypropylene resin is 100 mol%. More preferably. The polypropylene resin in the biaxially stretched film layer (A) may be used alone or in combination of two or more.
Among these, from the viewpoint of obtaining a biaxially stretched film layer (A) that is more excellent in performance balance such as heat resistance, moldability, mechanical properties, and rigidity, the polypropylene resin is homopolypropylene and propylene with ethylene or carbon number. Is preferably at least one selected from random copolymers with 4 to 10 α-olefins (hereinafter also referred to as propylene / α-olefin random copolymers).
The homopolypropylene according to this embodiment has a content of structural units derived from propylene of 99.0 mol% or more, preferably 99.99% when the total content of structural units constituting the homopolypropylene is 100 mol%. 5 mol% or more, more preferably 99.9 mol% or more, particularly preferably 100.0 mol%.

The propylene / α-olefin random copolymer according to this embodiment is a random copolymer of propylene and ethylene or an α-olefin having 4 to 10 carbon atoms. Examples of the α-olefin include ethylene, 1 -Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. These copolymers may be used alone or in admixture of two or more.
Among the propylene / α-olefin random copolymers, propylene / ethylene random copolymers, propylene / ethylene / 1-butene random copolymers, and propylene / 1-butene random copolymers are preferable.

  The polypropylene resin according to the present embodiment can be produced by various methods. For example, it can be produced using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

  The melting point of the polypropylene resin according to this embodiment is preferably 90 ° C. or higher and 175 ° C. or lower, more preferably, from the viewpoint of further improving the balance of heat resistance, mechanical properties, rigidity, fluidity, moldability, and the like. It is 95 ° C or higher and 170 ° C or lower, more preferably 100 ° C or higher and 167 ° C or lower.

  In accordance with ASTM D1238, the melt flow rate (MFR) of the polypropylene resin according to this embodiment measured under the conditions of 230 ° C. and 2.16 kg load is preferably 0.5 g from the viewpoint of fluidity and moldability. / 10 min or more, more preferably 1 g / 10 min or more, further preferably 2 g / 10 min or more, and from the viewpoint of further stabilizing the moldability, preferably 20 g / 10 min or less, more preferably 10 g / 10 min. Hereinafter, it is more preferably 7 g / 10 min or less.

(Filler)
The biaxially stretched film layer (A) according to this embodiment contains at least one filler selected from an organic filler and an inorganic filler as an essential component.
Examples of the filler used for the biaxially stretched film layer (A) include calcium carbonate, calcium sulfate, barium carbonate, barium sulfate, titanium oxide, magnesium hydroxide, magnesium carbonate, aluminum hydroxide, zinc oxide, magnesium oxide, and silica. , Inorganic fillers such as potassium titanate, calcium sulfite, calcium silicate, wollastonite, talc, mica, clay, kaolinite, montmorillonite, hydrotalcite; polystyrene resin particles, poly (meth) acrylic resin particles, etc. An organic filler etc. are mentioned. These fillers may be used individually by 1 type, and may be used in combination of 2 or more types. Among these, calcium carbonate is preferable because it is inexpensive and can further improve the moisture permeability of the moisture permeable film.

  In addition, the filler may be used as it is without treatment. In order to improve the interfacial adhesion with the thermoplastic resin and improve the dispersibility in the thermoplastic resin, the silane coupling agent, titanium coupling agent, interface The surface may be treated with an activator or the like.

(Other ingredients)
In the resin composition (A) according to this embodiment, a tackifier, a heat stabilizer, a weather stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, and an antiblocking agent are included as necessary. Various additives such as an antistatic agent, an antifogging agent, a pigment, and a dye may be added as long as the object of the present embodiment is not impaired.

(Preparation method of resin composition (A))
In the resin composition (A) according to this embodiment, for example, each component is mixed or melted by dry blending, tumbler mixer, Banbury mixer, single screw extruder, twin screw extruder, high speed twin screw extruder, hot roll, etc. -It can be prepared by kneading.

[Surface resin layer (B)]
The moisture-permeable film 10 according to the present embodiment suppresses poor adhesion to a molding machine, roll dirt, and the like, and at least one surface of the biaxially stretched film layer (A) in order to improve continuous film forming properties. A surface resin layer (B) is provided on the top. The surface resin layer (B) is preferably provided on both sides of the biaxially stretched film layer (A) from the viewpoint of further suppressing poor sticking to the molding machine and improving the continuous film forming property. .
In addition, from the viewpoint of further suppressing poor adhesion to a molding machine, roll dirt, and the like, and improving the continuous film forming property, the surface resin layer (B) is provided in the outermost layer of the moisture permeable film 10. Is preferred.

  Moreover, it is preferable that the surface resin layer (B) is provided so that it may contact | connect directly on the surface of a biaxially stretched film layer (A). Thereby, the manufacturing process of the moisture-permeable film 10 can be simplified.

In the moisture-permeable film 10 according to the present embodiment, the thickness of the surface resin layer (B) is preferably 5.0 μm or less, more preferably 3.0 μm or less, still more preferably 2.5 μm or less, and even more preferably 1. It is 5 μm or less, particularly preferably 0.6 μm or less.
In the moisture-permeable film 10 according to this embodiment, the total thickness of the surface resin layer (B) is 10 μm or less, preferably 6.0 μm or less, more preferably 5.0 μm or less, and even more preferably 3.0 μm. Hereinafter, it is particularly preferably 1.2 μm or less.
Here, the thickness of the surface resin layer (B) is the thickness of the surface resin layer (B) provided on one side of the biaxially stretched film layer (A), and the total thickness of the surface resin layer (B) is two. The sum total of the thickness of all the surface resin layers (B) provided in the axial stretched film layer (A) is said.
Moreover, when the thickness or total thickness of the surface resin layer (B) is not more than the above upper limit value, the moisture permeability and air permeability of the moisture permeable film 10 can be further improved.
Moreover, the adhesiveness of a biaxially stretched film layer (A) and a surface resin layer (B) improves because the thickness of a surface resin layer (B) is below the said upper limit, A biaxially stretched film layer (A ) It is easier to form the surface resin layer (B) thereon. That is, since it becomes easy to provide the surface resin layer (B) so as to be in direct contact with the surface of the biaxially stretched film layer (A), the manufacturing process of the moisture-permeable film 10 can be simplified.

In the moisture-permeable film 10 according to this embodiment, the thickness of the surface resin layer (B) is preferably 0.01 μm or more, more preferably 0.05 μm or more, and further preferably 0.1 μm or more.
Moreover, in the moisture-permeable film 10 which concerns on this embodiment, the total thickness of a surface resin layer (B) is 0.02 micrometer or more, More preferably, it is 0.1 micrometer or more, More preferably, it is 0.2 micrometer or more.
When the thickness or total thickness of the surface resin layer (B) is equal to or more than the above lower limit value, poor adhesion to a molding machine, roll contamination, and the like can be further suppressed, and continuous film-forming properties can be further improved.

  In the moisture-permeable film 10 according to the present embodiment, the surface resin layer (B) provided on one surface is preferably a single layer. Thereby, the manufacturing process of the moisture-permeable film 10 can be simplified further.

  Moreover, it is preferable that a surface resin layer (B) is extended | stretched simultaneously with the film in the state before extending | stretching of a biaxially stretched film layer (A). Thereby, since the moisture-permeable film 10 can be produced using a molding method such as a co-extrusion molding method, that is, a laminated film produced by one molding, the manufacturing process of the moisture-permeable film 10 is further simplified. Can do. Therefore, the surface resin layer (B) is preferably stretched.

  The surface resin layer (B) according to this embodiment can be formed, for example, by biaxially stretching an unstretched film layer composed of a resin composition (B) containing a thermoplastic resin.

(Resin composition (B))
The resin composition (B) according to the present embodiment includes a thermoplastic resin.
The content of the thermoplastic resin contained in the resin composition (B), that is, the surface resin layer (B) according to the present embodiment is preferably 60% by mass when the entire resin composition (B) is 100% by mass. 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, further preferably 80% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more. 100% by mass or less. Thereby, the sticking defect etc. to a molding machine can be suppressed more, and continuous film forming property can be made more favorable.

(Thermoplastic resin)
Although it does not specifically limit as a thermoplastic resin used for a surface resin layer (B), For example, Polyacrylic resin, such as polyolefin resin, polymethacrylic resin, such as polymethylmethacrylate resin, polymethylacrylate resin, polystyrene Resins, polyvinyl acetal resins, polyvinyl butyral resins, polyvinyl formal resins, polymethylpentene resins, polycarbonate resins, polyether ether ketone resins, polyether ketone resins, and other polyether resins, polyester resins, polyamide resins, polyamideimide resins , Polyimide resin, polyetherimide resin, styrene elastomer, polyolefin elastomer, polyurethane elastomer, polyester elastomer, polyamide elastomer, norbornene Fat, polytetrafluoroethylene resin, ethylenetetrafluoroethylene copolymer, polyvinylidene fluoride resin, polyvinyl fluoride resin, thermoplastic polyimide resin, polyvinylidene chloride resin, polyvinyl chloride resin, polyvinyl acetate resin, polysulfone resin, polyphenylene oxide resin And polyphenylene resins such as polyphenylene sulfide resin, polysulfone resin, polylactic acid resin, polyethersulfone resin, polyacrylonitrile resin, and styrene-acrylonitrile copolymer resin.
Among these, polyolefin resins are preferable from the viewpoint of excellent balance of mechanical properties, handleability, appearance, lightness, price, moldability, and the like. These thermoplastic resins may be used individually by 1 type, and may be used in combination of 2 or more types.

(Polyolefin resin)
Examples of the polyolefin resin used for the surface resin layer (B) include homopolymers of α-olefins such as ethylene, propylene, butene-1, hexene-1, 4-methyl-pentene-1, and octene-1, or High-pressure low-density polyethylene; Linear low-density polyethylene (LLDPE); High-density polyethylene; Polypropylene; Random copolymer of propylene and α-olefin having 2 to 10 carbon atoms; Polymer (EVA); ionomer resin and the like. These polyolefin resin may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, at least one selected from polyethylene resins and polypropylene resins is preferable, and polypropylene resins are more preferable.

(Polyethylene resin)
Examples of the polyethylene resin used for the surface resin layer (B) include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and ultrahigh molecular weight polyethylene. Among these, low density polyethylene and linear low density polyethylene are preferable, and linear low density polyethylene is more preferable. One type of polyethylene may be used, or two or more types may be used in combination.

  The melting point of the polyethylene resin according to this embodiment is preferably 95 ° C. or higher and 135 ° C. or lower, more preferably, from the viewpoint of further improving the balance of heat resistance, mechanical properties, rigidity, fluidity, moldability, and the like. It exists in the range of 100 degreeC or more and 130 degrees C or less.

  In accordance with ASTM D1238, the melt flow rate (MFR) of the polyethylene resin according to this embodiment measured at 190 ° C. and a load of 2.16 kg is preferably 0.5 g from the viewpoint of fluidity and moldability. / 10 min or more, more preferably 1 g / 10 min or more, further preferably 2 g / 10 min or more, and from the viewpoint of further stabilizing the moldability, preferably 30 g / 10 min or less, more preferably 20 g / 10 min. Hereinafter, it is more preferably 10 g / 10 min or less.

  The manufacturing method of the polyethylene-type resin which concerns on this embodiment is not specifically limited, It can manufacture by a well-known method. A commercially available polyethylene resin may be used.

(Polypropylene resin)
Examples of the polypropylene resin according to the present embodiment include homopolypropylene, a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like can be mentioned. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable, and ethylene is more preferable. These α-olefins may form a random copolymer with propylene, or may form a block copolymer. The content of the structural unit derived from ethylene or an α-olefin having 4 to 20 carbon atoms is preferably 5 mol% or less, preferably 2 mol% or less, when the entire polypropylene resin is 100 mol%. More preferably. The polypropylene resin in the surface resin layer (B) may be used alone or in combination of two or more.
Among these, from the viewpoint of obtaining a surface resin layer (B) that is more excellent in performance balance such as heat resistance, moldability, mechanical properties, and rigidity, the polypropylene resin is homopolypropylene and propylene with ethylene or 4 carbon atoms. At least one selected from random copolymers with 10 to 10 α-olefins (hereinafter also referred to as propylene / α-olefin random copolymers) is preferable.
The homopolypropylene according to this embodiment has a content of structural units derived from propylene of 99.0 mol% or more, preferably 99.99% when the total content of structural units constituting the homopolypropylene is 100 mol%. 5 mol% or more, more preferably 99.9 mol% or more, particularly preferably 100.0 mol%.

The propylene / α-olefin random copolymer according to this embodiment is a random copolymer of propylene and ethylene or an α-olefin having 4 to 10 carbon atoms. Examples of the α-olefin include ethylene, 1 -Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. These copolymers may be used alone or in admixture of two or more.
Among the propylene / α-olefin random copolymers, propylene / ethylene random copolymers, propylene / ethylene / 1-butene random copolymers, and propylene / 1-butene random copolymers are preferable.

  The polypropylene resin according to the present embodiment can be produced by various methods. For example, it can be produced using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

  The melting point of the polypropylene resin according to this embodiment is preferably 90 ° C. or higher and 175 ° C. or lower, more preferably, from the viewpoint of further improving the balance of heat resistance, mechanical properties, rigidity, fluidity, moldability, and the like. It is 95 ° C or higher and 170 ° C or lower, more preferably 100 ° C or higher and 167 ° C or lower.

  In accordance with ASTM D1238, the melt flow rate (MFR) of the polypropylene resin according to this embodiment measured under the conditions of 230 ° C. and 2.16 kg load is preferably 0.5 g from the viewpoint of fluidity and moldability. / 10 min or more, more preferably 1 g / 10 min or more, further preferably 2 g / 10 min or more, and from the viewpoint of further stabilizing the moldability, preferably 20 g / 10 min or less, more preferably 10 g / 10 min. Hereinafter, it is more preferably 7 g / 10 min or less.

(Other ingredients)
In the resin composition (B) according to the present embodiment, a filler, a tackifier, a heat stabilizer, a weather stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, an anti Various additives such as a blocking agent, an antistatic agent, an antifogging agent, a pigment, and a dye may be added as long as the object of the present embodiment is not impaired.

<Method for producing moisture-permeable film>
The moisture-permeable film 10 according to this embodiment includes, for example, a resin composition (A) for forming a biaxially stretched film layer (A) and a resin composition (B for forming a surface resin layer (B). ) Can be obtained by biaxially stretching using a known stretching method.
The molding apparatus and molding conditions are not particularly limited, and conventionally known molding apparatuses and molding conditions can be employed. As a molding apparatus, a multilayer T-die extruder, a multilayer inflation molding machine, or the like can be used. The stretching conditions are not particularly limited because they are appropriately adjusted depending on the content ratio and combination of the thermoplastic resin and the filler. For example, known production conditions for various biaxially stretched films can be employed.

<Use of moisture-permeable film>
The moisture permeable film 10 according to the present embodiment is excellent in moisture permeability and air permeability, and is also excellent in water resistance and mechanical properties. Therefore, it can be suitably used for applications requiring moisture permeability, breathability, water resistance, and mechanical properties. Such applications include, for example, packaging products such as foods and pharmaceuticals, desiccants, oxygen scavengers, alcohol volatilizers, freshness-preserving agents, sanitary products such as paper diaper back sheets and sanitary products back sheets, medical products Health care products, filter products, geotextile products, agricultural products, horticultural products, clothing such as simple jumpers, footwear products, bag products, household products, industrial products, construction products such as waterproof and breathable sheets for building materials, or Structural products and the like are preferred.

In addition, the moisture-permeable film according to the present embodiment may use the moisture-permeable film 10 according to the present embodiment as a part of the film according to the present embodiment depending on the application, or the present embodiment over the entire application article. You may use the moisture-permeable film 10 concerning.
Packaging products include, for example, food and pharmaceuticals, alcohol volatilizers, freshness preserving agent packaging, desiccant packaging, desiccant packaging, oxygen absorber packaging, gift boxes, file boxes, non-woven bags, etc. Book covers, envelopes, express envelopes, delivery bags, etc.
Construction and structural products include, for example, house wraps, asphalt overlays, road and railroad floors, golf courts, tennis courts, wall coverings, acoustic wall coverings, roofing materials, tile linings, soil Stabilizers, road underlays, foundation stabilizers, erosion prevention products, canal construction, drainage systems, geomembrane protection products, frost protection products, agricultural mulches, waterproof walls for ponds and canals, sand intrusion prevention walls for underdrainage, etc. Is mentioned.
Hygiene products include, for example, absorbent hygiene products (eg baby diapers, diapers, feminine hygiene products, adult incontinence products), hair removal strips, bandages, wound dressings, fragrance volatile parts of fragrance containers, disposable warmers Disposable bath towels, face towels, disposable slippers, footwear, top sheets, cover stock, consumer face masks, leg cuffs, collection / distribution layers, core wraps, back sheets, stretchable ears, landing zones, dusting layers and fixings Systems, wipes (eg wet wipes, skin care wipes, baby wipes, facial wipes, cleansing wipes, hand and body wipes, moist towels, personal hygiene wipes, feminine hygiene wipes, antibacterial wipes, medical wipes) and the like.
Medical and health care products include, for example, medical products that can be sterilized, medical packages, caps (eg, surgical disposable caps), protective clothing, surgical gowns, surgical masks, surgical face masks, surgical gowns, surgery Covers, surgical drapes, wraps, packs, sponges, bandages, wipes, bed linens, antifouling gowns, inspection gowns, laboratory coats, isolation gowns, transdermal drug delivery, shrouds, underpads, treatment packs, Heat packs, ostomy bag liners, fixation tapes, incubator mattresses, sterilization wraps, wound care, cold / hot packs, drug delivery systems (eg patches etc.) and the like.
As clothing, footwear products, and heel products, for example, interlining (for example, protective clothing, overcoat front, collar, facing, waistband, lower collar, etc.), disposable underwear, shoe components (for example, shoelace small hole reinforcement, Sports shoes, sandal reinforcements, inner sole lining, etc.), binders, compositions, (laundry) precaution labels, and the like.

  Moreover, the moisture-permeable film which concerns on this embodiment can also be used suitably as a film which comprises a package body. The package according to the present embodiment is, for example, a packaging bag used for the purpose of containing food, medicine, desiccant, oxygen scavenger, alcohol volatilizer, freshness-retaining agent, etc. Is housed. Moreover, the package according to the present embodiment may use the moisture-permeable film 10 according to the present embodiment for a part of the package according to the application, or the moisture-permeable film 10 according to the present embodiment may be used for the entire package. May be.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  Hereinafter, the present embodiment will be described in detail with reference to examples and comparative examples. In addition, this embodiment is not limited to description of these Examples at all.

1. Raw materials The raw materials used in Examples and Comparative Examples are shown below.
(1) Polypropylene resin PP1: Homopolypropylene (MFR: 3 g / 10 min, melting point: 165 ° C., manufactured by Prime Polymer Co., Ltd.)
(2) Filler-containing masterbatch MB1: Masterbatch containing calcium carbonate and homopolypropylene (calcium carbonate content: 80% by mass, homopolypropylene content: 20% by mass, average particle size of calcium carbonate 4.5 μm)

2. Measurement and Evaluation Method (1) MFR of polypropylene resin
Based on ASTM D1238, the measurement was performed under the conditions of 230 ° C. and 2.16 kg load.

(2) Melting | fusing point of polypropylene-type resin The temperature of the maximum melting peak of the DSC curve of polypropylene obtained using DSC (differential scanning calorimeter) was made into melting | fusing point.

(3) Presence / absence of vents The surface resin layer (B) was peeled off and the surface of the moisture-permeable film (that is, the surface of the biaxially stretched film layer (A)) was observed with an electron microscope to examine the presence or absence of vents. Here, air holes having a maximum pore diameter of 5 μm or more and 50 μm or less were used.

(4) Evaluation of continuous film-forming property The continuous film-forming property of the moisture-permeable film was evaluated according to the following criteria.
○: When continuous film formation, no sticking failure to the chill roll or roll dirt occurs, and continuous film formation is good. ×: When continuous film formation, sticking failure to the chill roll occurs, continuous Films that cannot be formed and / or roll film stains that occur during continuous film formation and cannot be formed continuously

(5) Evaluation of appearance The continuous film-forming property of the moisture-permeable film was evaluated according to the following criteria.
○: No surface is observed on the surface.
X: The surface where the surface is observed

(6) Evaluation of moisture permeability The moisture permeable films obtained in Examples and Comparative Examples were folded back and heat sealed on two sides to form a bag. Thereafter, calcium chloride was added as a content. Next, the other side was heat-sealed to produce a bag having a surface area of 0.01 m ² . Subsequently, the obtained bag was stored for 1 hour under the conditions of 40 ° C. and humidity 90% RH. The weight of calcium chloride before and after storage was measured, and the water vapor permeability (g / (m ² · 24 h)) was calculated from the difference.
Next, the moisture permeability of the moisture permeable film was evaluated according to the following criteria.
◯: Water vapor permeability of 20 g / (m ² · 24 h) or more ×: Water vapor permeability of less than 20 g / (m ² · 24 h) In addition, for those having a continuous film forming property of “x”, evaluation of moisture permeability Is not done.

[Examples 1-6 and Comparative Examples 1-3]
Unstretched films were obtained by extruding each layer at the blending ratio and layer configuration shown in Table 1. Subsequently, the obtained unstretched film was biaxially stretched to produce moisture permeable films, and each evaluation was performed. Extrusion conditions and biaxial stretching conditions are as follows. Here, the surface resin layer (B) formed on one surface of the biaxially stretched film layer (A) is called a surface resin layer 1, and the surface resin layer (B) formed on the other surface is a surface resin layer. Call it 2.
Multi-layer extruder: 60 mmφ multi-layer T-die extruder (L / D = 27, manufactured by Screw Seiki Co., Ltd.)
Extrusion set temperature: 200-250 ° C
Machining speed: 4.0 m / min
Longitudinal stretching temperature: 120-145 ° C
Longitudinal stretch ratio: 5.0 times Transverse stretching temperature: 160-180 ° C
Horizontal stretch ratio: 10.0 times Table 1 shows the results obtained. In addition, about the thing whose continuous film formability is "x", the measurement of thickness is not performed.

  The moisture-permeable films of the examples were excellent in moisture permeability, continuous film-forming property and appearance, and could highly control moisture permeability by the total thickness of the surface resin layer (B). On the other hand, the moisture-permeable film of the comparative example was inferior in the balance between moisture permeability and continuous film-forming property.

10 Moisture permeable film A Biaxially stretched film layer B Surface resin layer

Claims (11)

A biaxially stretched film layer (A) comprising a thermoplastic resin and at least one filler selected from organic fillers and inorganic fillers;
A surface resin layer (B) provided on at least one surface of the biaxially stretched film layer (A),
The moisture-permeable film whose total thickness of the said surface resin layer (B) is 10 micrometers or less. In the moisture-permeable film according to claim 1,
The moisture-permeable film whose content of the filler in the biaxially stretched film layer (A) is 40% by mass or more and 70% by mass or less when the total amount of the biaxially stretched film layer (A) is 100% by mass. . In the moisture-permeable film according to claim 1 or 2,
The moisture-permeable film in which the thermoplastic resin contains a polyolefin resin. In the moisture-permeable film according to claim 3,
A moisture-permeable film in which the polyolefin resin includes at least one selected from a polyethylene resin and a polypropylene resin. In the moisture-permeable film as described in any one of Claims 1 thru | or 4,
The biaxially stretched film layer (A) is a moisture-permeable film having air holes on the surface. In the moisture-permeable film as described in any one of Claims 1 thru | or 5,
The filler is calcium carbonate, calcium sulfate, barium carbonate, barium sulfate, titanium oxide, magnesium hydroxide, magnesium carbonate, aluminum hydroxide, zinc oxide, magnesium oxide, silica, potassium titanate, calcium sulfite, calcium silicate, wax. A moisture-permeable film comprising one or more selected from lastite, talc, mica, clay, kaolinite, montmorillonite, hydrotalcite, polystyrene resin particles and poly (meth) acrylic resin particles. In the moisture-permeable film as described in any one of Claims 1 thru | or 6,
A moisture-permeable film having a water vapor permeability of 20 g / (m ² · 24 h) or more at 40 ° C. and 90% RH. In the moisture-permeable film as described in any one of Claims 1 thru | or 7,
The moisture-permeable film in which the surface resin layer (B) contains a polyolefin resin. The moisture-permeable film according to claim 8,
The moisture-permeable film in which the polyolefin resin in the surface resin layer (B) contains at least one selected from polyethylene resins and polypropylene resins. In the moisture-permeable film as described in any one of Claims 1 thru | or 9,
Hygiene products, medical products, healthcare products, filter products, geotextile products, agricultural products, horticultural products, clothing, footwear products, bag products, household products, industrial products, packaging products, construction products and structures A moisture-permeable film used for any one selected from the group consisting of products for medical use.   The package using the moisture-permeable film as described in any one of Claims 1 thru | or 9.

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