JP2021172909A - Biodegradable nonwoven face mask - Google Patents

Abstract

To provide a face mask composed of nonwoven fabric that is flexible, highly rigid, is excellent in shape holdability, is easy to manufacture, and is suited to electret processing.SOLUTION: A biodegradable nonwoven face mask partially includes nonwoven fabric which is formed by fiber composed of alloy resin composition and is electretized. The alloy resin composition contains a specific quantity of plasticizer which is selected from a group composed of biodegradable resin component containing polylactic acid, olefin resin, lactic acid, lactic acid oligomer of 3,000 weight average molecular weight or less and branched polylactic acid, inorganic substance powder, and ethylenic polymer wax whose weight average molecular weight ranges between 400 and 5,000.SELECTED DRAWING: None

Description

The present invention relates to a mask made of a non-woven fabric containing a biodegradable material.

Masks for blocking bacteria, viruses, fungi that cause diseases, pollen, house dust, and suspended particulate matter in dust and exhaust gas that cause bronchitis, asthma, allergic diseases, etc. Wearing is effective. The main material of the mask is woven fabric or non-woven fabric made of various fibers, and most of these fibers are manufactured from petroleum-derived resin. In recent years, from the viewpoint of environmental protection, studies on replacing such petroleum-derived raw materials with non-petroleum-derived raw materials have been promoted in each field, and biodegradable resins such as polylactic acid should be used as raw materials for masks and the like. Is also being studied (see, for example, Patent Documents 1 and 2). Further, in order to reduce the consumption of petroleum-derived raw materials, a composition in which a thermoplastic resin is highly filled with an inorganic substance powder, particularly calcium carbonate, which is abundant in nature, has been proposed and put into practical use (for example,). See Patent Document 3 etc.).

As a technique for improving the filter characteristics of a mask, an electret treatment has been studied and put into practical use. This technique is a process of imparting a relatively long-life static charge to a cloth such as a non-woven fabric constituting a mask. The electretized non-woven fabric can capture fine particles by static charge in addition to the filter mechanism by the network structure. Therefore, in these non-woven fabrics, fine particles can be blocked even if the fiber mesh is enlarged, so that both filter performance and air permeability can be achieved at the same time. However, the above-mentioned non-woven fabric made of polylactic acid as a raw material has a problem that the charging effect due to electretization is not sufficiently obtained, and the processability is low due to the low flexibility and large heat shrinkage of the polylactic acid fiber.

In order to solve the above problems, blending of other resins with polylactic acid is also being considered. For example, Patent Document 4 proposes a non-woven fabric formed of alloy fibers made of a polyester resin such as polylactic acid and an olefin resin and made into an electret. However, alloy fibers made of polylactic acid and an olefin resin such as polypropylene are difficult to produce and have a problem of low production efficiency. Further, the non-woven fabric formed of such alloy fibers has problems such as low rigidity and inferior shape retention when formed into a three-dimensional mask shape.

Japanese Unexamined Patent Publication No. 2008-188082 Japanese Unexamined Patent Publication No. 2006-274481 Japanese Unexamined Patent Publication No. 2013-01093 JP-A-2009-221618

The present invention has been made in view of the above circumstances, and while using an alloy resin based on a biodegradable resin such as polylactic acid as a main raw material, it is flexible, has high rigidity, has excellent shape retention, and is easy to manufacture. It is an object of the present invention to provide a mask made of a non-woven fabric suitable for electretization treatment.

As a result of diligent studies, the present inventors have identified specific types of inorganic substance powders, plasticizers, and waxes in fibers composed of an alloy resin composition of a biodegradable resin such as polylactic acid and an olefin resin. The present invention has been completed with the knowledge that a non-woven fabric mask that is flexible, has high rigidity, and has good shape retention can be obtained with high production efficiency by containing the amount.

Specifically, the present invention provides:
(1) A biodegradable non-woven fabric mask containing at least a part of an electretized non-woven fabric formed of fibers made of an alloy resin composition.
The alloy resin composition
Biodegradable resin component containing polylactic acid,
Olefin resin,
A plasticizer selected from the group consisting of lactic acid, a lactic acid oligomer having a weight average molecular weight of 3,000 or less, and branched polylactic acid.
Contains inorganic substance powder and ethylene polymer wax with a weight average molecular weight of 400 or more and 5,000 or less.
The plasticizer is contained in a proportion of 1 to 5% by mass when the total mass of the plasticizer and the biodegradable resin component is 100%.
The olefin resin and the inorganic substance powder are contained in a mass ratio of 50:50 to 10:90, and the ethylene polymer wax contains a total amount of 100 of the olefin resin and the inorganic substance powder. A biodegradable non-woven fabric mask containing 0.1 parts by mass or more and 3.0 parts by mass or less with respect to parts by mass.

(2) The biodegradable resin component contains polyL-lactic acid having a weight average molecular weight (Mw) of 50,000 or more and 300,000 or less in a proportion of 10 to 100% by mass of the total biodegradable resin component. The biodegradable non-woven fabric mask according to (1).

(3) The olefin-based resin contains a polypropylene-based resin, and the polypropylene-based resin is a polypropylene homopolymer having a melt flow rate (MFR) of 50 g / 10 minutes or more and 70 g / 10 minutes or less (1). ) Or (2). The biodegradable non-woven fabric mask.

(4) the ethylene density of the polymer wax is not more than 0.890 g / cm ³ or more 0.990 g / cm ³ (1) biodegradable nonwoven mask according to any one of - (3).

(5) Any of (1) to (4), wherein the inorganic substance powder is heavy calcium carbonate particles having an average particle diameter of 1.0 μm or more and 5.0 μm or less by an air permeation method according to JIS M-8511. The biodegradable non-woven fabric mask according to one.

(6) The BET specific surface area of the heavy calcium carbonate particles is 0.1 m ² / g or more and 10.0 m ² / g or less, and the roundness is 0.50 or more and 0.95 or less. Biodegradable non-woven mask.

(7) The alloy resin composition further contains heavy calcium carbonate particles as a second inorganic substance powder.
The content of the second inorganic substance powder is 50% by mass or more and 90% by mass or less when the total mass of the second inorganic substance powder, the biodegradable resin component, and the plasticizer is 100%. Is the ratio of
The average particle size calculated from the measurement result of the specific surface area of the second inorganic substance powder by the air permeation method according to JIS M-8511 is 1.0 μm or more and 10.0 μm or less, and
The biodegradable non-woven fabric mask according to any one of (1) to (6), wherein the BET specific surface area of the second inorganic substance powder is 0.1 m ² / g or more and 10.0 m ^{2 / g or less.}

(8) The biodegradable non-woven fabric mask according to (7), wherein the roundness of the second inorganic substance powder is 0.50 or more and 0.95 or less.

(9) The method for producing a biodegradable non-woven fabric mask according to any one of (1) to (8).
Including the step of producing the alloy resin composition.
The step is
A step of producing a biodegradable resin composition by mixing the biodegradable resin component and the plasticizer.
A step of mixing the olefin resin, the inorganic substance powder, and the ethylene polymer wax to produce an olefin resin composition, and the biodegradable resin composition and the olefin resin composition. A method for producing a biodegradable non-woven plastic mask, which comprises a step of mixing.

(10) When the inorganic substance powder is used as the first inorganic substance powder,
In the step of producing the biodegradable resin composition,
The method for producing a biodegradable non-woven fabric mask according to (9), wherein the biodegradable resin component, the plasticizer, and a second inorganic substance powder are mixed to produce the biodegradable resin composition. ..

According to the present invention, while using an alloy resin based on a biodegradable resin as a main raw material, it is possible to provide a mask made of a non-woven fabric which is flexible, has high rigidity, has excellent shape retention, is easy to manufacture, and is suitable for electret formation treatment. Can be done.

Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not particularly limited thereto.

The mask according to the present invention is a biodegradable non-woven fabric mask formed of fibers made of an alloy resin composition and containing at least a part of an electretized non-woven fabric.
The alloy resin composition
Biodegradable resin component containing polylactic acid,
Olefin resin,
A plasticizer selected from the group consisting of lactic acid, a lactic acid oligomer having a weight average molecular weight of 3,000 or less, and branched polylactic acid.
Contains inorganic substance powder and ethylene polymer wax with a weight average molecular weight of 400 or more and 5,000 or less.
The plasticizer is contained in a proportion of 1 to 5% by mass when the total mass of the plasticizer and the biodegradable resin component is 100%.
The olefin resin and the inorganic substance powder are contained in a mass ratio of 50:50 to 10:90, and the ethylene polymer wax contains a total amount of 100 of the olefin resin and the inorganic substance powder. It is characterized in that it is contained in a ratio of 0.1 parts by mass or more and 3.0 parts by mass or less with respect to parts by mass.

≪Biodegradable resin composition≫
The biodegradable non-woven fabric mask according to the present invention (hereinafter, may be simply referred to as “mask”) is a fiber in which at least a part, usually a part or all of a covering part which is usually a main part, is made of an alloy resin composition. It is composed of a non-woven fabric formed of and made into an electret. This alloy resin composition is selected from the group consisting of a biodegradable resin component containing polylactic acid and an olefin resin as a base polymer, lactic acid, a lactic acid oligomer having a weight average molecular weight of 3,000 or less, and branched polylactic acid. It contains a plasticizer, an inorganic substance powder, and an ethylene polymer wax having a weight average molecular weight of 400 or more and 5,000 or less.

[Biodegradable resin]
The biodegradable resin is not particularly limited except that it contains polylactic acid, and various resins can be used depending on the use and function of the mask. For example, it may be a polylactic acid homopolymer alone, or a copolymer of lactic acid and another monomer, or a mixture with another biodegradable resin such as a cellulose acetate resin or starch can be used. ..

However, the biodegradable resin component in the present invention preferably contains polylactic acid in a proportion of 10% by mass or more. Polylactic acid has high biodegradability among various biodegradable resins and is easily available because it is mass-produced. It has an excellent balance with physical properties such as strength and heat resistance, and the results of studies to improve such physical properties have also been reported. Therefore, it is easy to modify the resin into a resin having preferable physical characteristics according to the use of the mask and the like. The content of polylactic acid in the resin component is more preferably 50% by mass or more, further preferably 70% by mass or more, particularly preferably 90% by mass or more, and particularly preferably 100% by mass.

The preferred weight average molecular weight (Mw) of polylactic acid is generally 50,000 or more and 300,000 or less, particularly 100,000 or more and 200,000 or less. Polylactic acid having a molecular weight in this range generally has an excellent balance of physical properties such as biodegradability, moldability, and strength. Of these, poly-L-lactic acid having such a molecular weight is preferable. In a preferred embodiment of the present invention, the biodegradable resin composition contains poly-L-lactic acid having a weight average molecular weight of 50,000 or more and 300,000 or less in a proportion of 10 to 100% by mass of the total resin component.

Poly L-lactic acid is a polymer containing L-lactic acid as a main component. Poly-L-lactic acid contains D-lactic acid, which is an optical isomer of L-lactic acid. In the present invention, the content ratio of L-lactic acid unit in the total lactic acid component of the polylactic acid polymer is 90 mol% or more. In particular, it is preferably 95 mol% or more. Poly L-lactic acid may also contain other monomers, for example, 3 mol% or less, particularly about 2 mol% or less. Other monomers include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, neopentyl glycol, glycerin, pentaerythritol, bisphenol A, polyethylene glycol, polypropylene glycol, etc. Glycols such as polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecandioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 4, Dicarboxylic acids such as 4'-diphenyl ether dicarboxylic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxycarboxylic acids such as hydroxybenzoic acid, caprolactone, valerolactone, propiolactone, undecalactone Glycols such as can be used.

[Plasticizer]
In the present invention, in order to improve the flexibility of the fiber composed of the alloy resin composition, it is composed of lactic acid, a lactic acid oligomer having a weight average molecular weight of 3,000 or less, and branched polylactic acid, which are suitable for plasticizing polylactic acid. A plasticizer selected from the group is blended. These plasticizers are known and are described, for example, in International Publication WO2010 / 082639. In addition to these, triethyl citrate, acetyl triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, o-benzoyl benzoate, Diacetin, epoxidized soybean oil, etc. can be used, but a lactic acid-based plasticizer is most suitable from the viewpoint of compatibility with polylactic acid. These plasticizers are contained in a proportion of 1 to 5% by mass when the total mass of the plasticizer and the biodegradable resin component is 100%. If the content is less than 1% by mass, it is difficult to improve the flexibility of the fiber, and if it exceeds 5% by mass, bleeding may occur and the wearing feeling of the mask may be deteriorated. The content of these plasticizers is preferably 1 to 4% by mass, more preferably 2 to 4% by mass, and particularly preferably 2 to 3% by mass.

[Olefin resin]
The olefin resin is not particularly limited, and various resins can be used depending on the intended use and function. The olefin-based resin is a polyolefin-based resin containing an olefin component unit as a main component, and examples thereof include polyethylene-based resins, polypropylene-based resins, polymethyl-1-pentene, and ethylene-cyclic olefin copolymers. Not limited to. Ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, metal salt of ethylene-methacrylic acid copolymer (ionomer), ethylene-acrylic acid alkyl ester copolymer, ethylene- Functional group-containing polyolefin-based resins such as a methacrylic acid alkyl ester copolymer, maleic acid-modified polyethylene, and maleic acid-modified polypropylene can also be used. The term "main component" means that the polyolefin component unit contains 50% by mass or more of the olefin component unit, and the content thereof is preferably 75% by mass or more, more preferably 85% by mass. The above is more preferably 90% by mass or more. The method for producing the polyolefin resin is not particularly limited, and may be obtained by any of a method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator such as oxygen or peroxide, or the like. good.

However, in the present invention, it is preferable that the olefin resin contains a polypropylene resin. Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by mass or more, and examples thereof include a propylene homopolymer and a copolymer with another α-olefin copolymerizable with propylene. Other α-olefins copolymerizable with propylene include, for example, ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene. , 1-Heptene, 3-Methyl-1-hexene and other α-olefins having 4 to 10 carbon atoms are exemplified. These polypropylene-based resins are contained in an amount of preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the olefin-based resin in the alloy resin composition. Above all, it is preferable that the olefin resin is composed of only a polypropylene resin, particularly a propylene homopolymer. In general, polypropylene-based resin has an excellent balance between mechanical strength and heat resistance, and can be preferably used as a raw material for a non-woven fabric constituting a mask.

Propylene homopolymers include any of isotactics, syndiotactics, atactics, hemiisotactics and linear or branched polypropylenes exhibiting varying degrees of stereoregularity. Further, the copolymer with another α-olefin copolymerizable with propylene may be a random copolymer or a block copolymer, and further, not only a binary copolymer but also a ternary copolymer. It may be a polymer. Specifically, for example, an ethylene-propylene random copolymer, a butene-1-propylene random copolymer, an ethylene-butene-1-propylene random ternary copolymer, an ethylene-propylene block copolymer, and the like can be exemplified. .. It should be noted that other olefins copolymerizable with propylene in the copolymer may be contained in a proportion of 25% by mass or less, particularly 15% by mass or less, when the total olefin resin is 100% by mass. preferable. In addition, these polypropylene-based resins can be used alone or in combination of two or more.

In the present invention, various known polypropylene-based resins including the above can be used, but the melt flow rate (MFR) is preferably 50 g / 10 minutes or more and 70 g / 10 minutes or less, particularly 55 g / 10. Use a polypropylene homopolymer of minutes or more and 65 g / 10 minutes or less. By using a polypropylene homopolymer having an MFR in this range, the spinnability of the alloy resin composition is enhanced, and a non-woven fabric having more excellent quality stability and uniformity can be obtained. As described above, the polypropylene resin may have any stereoregularity, but polypropylene having an isotactic structure as the main component is preferably used. By using polypropylene having such a three-dimensional structure, the spinnability and the physical properties of the obtained non-woven fabric can be further improved. From the same viewpoint, density 0.86 g / cm ³ or more 0.95 g / cm ³ or less, and particularly to use polypropylene 0.88~0.93g / cm ³ preferred.

[Amount of resin component]
The blending ratio of the biodegradable resin component and the olefin resin in the alloy resin composition is not particularly limited, and can be arbitrarily set according to the desired physical properties and processability. However, the mass ratio of the biodegradable resin component: the olefin resin is preferably about 50/50 to 99/1. By setting the same mass ratio in this range, the electret processing described later can be made more effective. The mass ratio of the biodegradable resin component: the olefin resin is more preferably 60/40 to 95/5, and particularly preferably about 70/30 to 90/10.

[Inorganic substance powder]
The inorganic substance powder is not particularly limited, and is, for example, carbonates such as calcium, magnesium, aluminum, titanium, iron, and zinc, sulfates, silicates, phosphates, borates, oxides, or water thereof. Japanese powdered ones can be mentioned. Specifically, for example, calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, sulfuric acid. Aluminum, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous soil, sericite, silas, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, dolomite, graphite And so on. These may be synthetic or derived from natural minerals, and they may be used alone or in combination of two or more.

Further, the shape of the inorganic substance powder is not particularly limited, and may be in the form of particles, flakes, granules, fibers, or the like. Further, the particulate matter may be a spherical shape as generally obtained by a synthetic method, or an indefinite shape as obtained by subjecting the collected natural mineral to pulverization. ..

These inorganic substance powders are preferably calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, barium sulfate and the like, and calcium carbonate is particularly preferable. preferable. Further, the calcium carbonate is either so-called light calcium carbonate prepared by a synthetic method or so-called heavy calcium carbonate obtained by mechanically crushing and _{classifying a natural raw material containing CaCO 3 as a main component such as limestone.} However, it is possible to combine these, but it is more preferable to use heavy calcium carbonate.

[Heavy calcium carbonate particles]
Here, heavy calcium carbonate is obtained by mechanically crushing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by a chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, but the dry method is preferable from the viewpoint of economy. The heavy calcium carbonate particles are characterized by surface irregularity and a large specific surface area due to the particle formation being carried out by a pulverization treatment, unlike, for example, light calcium carbonate produced by a synthetic method. Due to the irregularity and specific surface area of the heavy calcium carbonate particles, the heavy calcium carbonate particles have more contact interfaces with the resin component when blended in the resin. Effective for uniform dispersion.

The heavy calcium carbonate particles used in the present invention have an average particle diameter of 1.0 μm or more and 10.0 μm or less, particularly 1.0 μm or more, calculated from the measurement results of the specific surface area by the air permeation method according to JIS M-8511. It is preferably 5.0 μm or less. In particular, it is preferable that the particle size distribution does not contain particles having a particle size of 50.0 μm or more. On the other hand, if the particles become too fine, the viscosity may be significantly increased when kneaded with the resin component, and the spinnability may be deteriorated. For the measurement by the air permeation method, for example, an instrument such as a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used. The average particle size of the heavy calcium carbonate particles is more preferably 1.5 μm or more and 4.5 μm or less, and further preferably 2.0 μm or more and 4.0 μm or less.

The specific surface area of the heavy calcium carbonate particles by the BET adsorption method ^{is preferably 0.1 m 2} / g or more and 10.0 m ² / g or less. The BET adsorption method referred to here is a nitrogen gas adsorption method. When the specific surface area is within this range, the physical properties of the obtained non-woven fabric are improved, but the spinnability is not significantly reduced by blending the heavy calcium carbonate particles. The specific surface area of the heavy calcium carbonate particles is more preferably 0.2 m ² / g or more and 5.0 m ² / g or less, and particularly preferably 1.0 m ² / g or more and 3.0 m ² / g or less.

Further, it is preferable that the heavy calcium carbonate particles are irregular to some extent, that is, the degree of spheroidization of the particle shape is low. Specifically, it is desirable that the roundness is 0.50 or more and 0.95 or less, more preferably 0.55 or more and 0.93 or less, and further preferably 0.60 or more and 0.90 or less. In the present invention, when the roundness of the heavy calcium carbonate particles used is within this range, the strength and spinnability of the non-woven fabric are also appropriate.

Here, the roundness can be expressed by (projected area of particles) / (area of a circle having the same perimeter as the projected perimeter of particles). The method for measuring the roundness is not particularly limited, but for example, the projected area of the particles and the projected perimeter of the particles are measured from a micrograph and defined as (A) and (PM), respectively, and the projected perimeter of the particles. Let (r) be the radius of a circle having the same perimeter as the length, and (B) be the area of a circle having the same perimeter as the projected perimeter of the particle.
Roundness = A / B = A / πr ² = A × 4π / (PM) ²
Will be. For these measurements, it is possible to obtain the roundness of the projection drawing of each particle obtained by a scanning microscope or a stereomicroscope by using image analysis software that is generally commercially available.

In addition, in order to enhance the dispersibility of the inorganic substance powder such as heavy calcium carbonate particles, the surface of the particles may be surface-modified in advance according to a conventional method. Examples of the surface modification method include a physical method such as plasma treatment and a method of chemically surface-treating the surface with a coupling agent or a surfactant. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. The surfactant may be anionic, cationic, nonionic or amphoteric, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts. Further, when heavy calcium carbonate is used, the particle surface of the heavy calcium carbonate may be partially oxidized and partially contain the composition of calcium oxide.

[Content of inorganic substance powder]
The amount of the inorganic substance powder contained in the alloy resin composition may be such that the mass ratio of the olefin resin and the inorganic substance powder is 50:50 to 10:90, and the desired physical properties and biodegradable resin component are used. And, depending on the type of the olefin resin and the mass ratio of both, it can be any ratio within the above range. The mass ratio of the olefin resin to the inorganic substance powder may be a mass ratio of 50:50 to 10:90, preferably a ratio of 48:52 to 10:90, and is 45:55 to 20:80. The ratio is more preferably 40:60 to 25:75. By setting the content of the inorganic substance powder to be equal to or higher than the content of the olefin resin, the biodegradability of the biodegradable resin composition can be further enhanced. Further, if the content ratio of the inorganic substance powder is about 9 times or less the content of the olefin resin, spinning does not become difficult.

[Second inorganic substance powder]
The alloy resin composition preferably contains heavy calcium carbonate particles as the second inorganic substance powder in addition to the above-mentioned inorganic substance powder. As a result, the compatibility between the biodegradable resin component in the alloy resin composition, particularly polylactic acid, and the olefin resin can be enhanced, and a mask having sufficient physical properties such as strength can be produced. The heavy calcium carbonate particles used as the second inorganic substance powder may be those exemplified above in the description of the inorganic substance powder (hereinafter, may be referred to as “first inorganic substance powder”). That is, the heavy calcium carbonate particles used as the second inorganic substance powder have an average particle diameter of 1.0 μm or more and 10.0 μm or less, and a BET specific surface area of 0.1 m ² / g or more and 10.0 m ² / g or less. It is preferable that the roundness is 0.50 or more and 0.95 or less. When heavy calcium carbonate particles are used as the first inorganic substance powder, the same type of heavy calcium carbonate particles can be used as the second inorganic substance powder, or different types of heavy calcium carbonate particles are used. You can also do it. For example, heavy calcium carbonate particles having an average particle size of 1.0 μm or more and 5.0 μm or less as the first inorganic substance powder, and a weight of 5.0 μm or more and 10.0 μm or less as the second inorganic substance powder. It is also possible to use each of the quality calcium carbonate particles.

The content of the second inorganic substance powder is 50% by mass or more and 90% by mass or less when the total mass of the second inorganic substance powder and the above-mentioned biodegradable resin component and plasticizer is 100%. The ratio is preferably 52% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 80% by mass or less, and 60% by mass or more and 75% by mass or less. The ratio is particularly preferable. In particular, when heavy calcium carbonate particles are used as the first inorganic substance powder, the total amount of the heavy calcium carbonate particles as the first and second inorganic substance powders is 40 to 90% by mass of the entire alloy resin composition. In particular, it is preferably 50 to 75% by mass. Within such a range, the biodegradability and spinnability can be improved.

[Ethylene polymer wax]
As described above, the alloy resin composition contains an ethylene polymer wax having a weight average molecular weight of 400 or more and 5,000 or less. The content of the ethylene polymer wax is 0.1 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the total amount of the olefin resin and the first inorganic substance powder described above. The content can be variously set according to the mass ratio of the olefin resin and the inorganic substance powder, the desired physical properties, processability, and the like. Preferably, 0.2 parts by mass or more and 2.5 parts by mass or less, more preferably 0.2 parts by mass or more and 1.5 parts by mass or less, based on 100 parts by mass of the total amount of the olefin resin and the first inorganic substance powder. In particular, it is 0.3 parts by mass or more and 1.0 part by mass or less.

Here, as the ethylene-based polymer wax, any known wax can be used. For example, High Wax (registered trademark) and Excelex (registered trademark) manufactured by Mitsui Chemicals, Inc., Sun Wax (registered trademark) manufactured by Sanyo Kasei Kogyo, Eporen (registered trademark) manufactured by Eastman Chemical Co., Ltd., and Allyed Singnals Co., Ltd. Allied wax (registered trademark), Paraflint (registered trademark) manufactured by SASOL, etc. are commercially available. The "ethylene-based polymer wax" includes not only ethylene homopolymers, but also copolymers of ethylene and α-olefins, and polymers containing polypropylene as a main unit (hence, "polyolefin wax"). ”), But any of them can be used. It is also possible to use a plurality of types of ethylene polymer waxes in combination.

The ethylene-based polymer wax may have a weight average molecular weight within the above-mentioned range, and waxes having various molecular weights can be used depending on the type and molecular weight of the thermoplastic resin used in combination. If the weight average molecular weight is less than about 400, the ethylene polymer wax may bleed out, while if the weight average molecular weight exceeds about 5,000, each component in the alloy resin composition. The effect of improving the dispersibility of is reduced. Further, an ethylene polymer wax having a weight average molecular weight of 500 or more and 4000 or less, and more preferably an ethylene polymer wax having a weight average molecular weight of 1000 or more and 3000 or less is used.

Further, when a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is used as the ethylene-based polymer wax, the number of carbon atoms of the α-olefin to be copolymerized with ethylene is 3 to 8 carbon atoms. Is preferable, the carbon number of 3 to 4 is more preferable, and the carbon number of 3 is particularly preferable. When the carbon number of the α-olefin to be copolymerized with ethylene is within the above-mentioned range, the spinnability is improved and the properties such as the strength of the non-woven fabric can be improved. Even when an ethylene homopolymer is used as the ethylene-based polymer wax, it exhibits excellent spinnability.

The ethylene-based polymer wax may be produced by any of a commonly used method of producing a low molecular weight polymer by polymerization or a method of reducing the molecular weight of a high molecular weight ethylene-based polymer by heating and reducing it. , There are no particular restrictions. Further, the ethylene-based polymer wax may be one that has been purified by a method such as solvent separation or distillation in which the wax is separated by the difference in solubility in a solvent.

Further, the melting point and softening temperature of the ethylene polymer wax are not particularly limited. For example, those having a melting point of 90 to 130 ° C., particularly those having a melting point of 95 to 125 ° C., or those having a softening temperature of 95 to 135 ° C., particularly those having a softening temperature of 100 to 130 ° C., and the like can be mentioned.

As for the density of the ethylene polymer wax, but are not particularly limited, it is preferably 0.890~0.990g / cm ^3, a 0.900~0.980g / cm ³ Is more preferable. When an ethylene-based polymer wax having a density within the above range is used, the spinnability of the alloy resin composition tends to be excellent.

In the alloy resin composition, the difference between the density of the olefin resin and the density of the ethylene polymer wax is not particularly limited ^{, but is preferably 0.10 g / cm 3} or less, preferably 0.08 g / cm. more preferably cm ³ or less, and particularly preferably 0.05 g / cm ³ or less. When the density difference is within the above range, the spinnability is improved and the properties such as strength can be enhanced.

[Other additives]
The alloy resin composition may contain a resin other than the above in a small amount, for example, in an amount of 20% by mass or less, particularly about 10% by mass or less of the resin component. For example, a synthetic resin such as polyamide, polyester, or polyurethane may be mixed.

[Other additives]
In the alloy resin composition, other additives can be added as an auxiliary agent, if necessary. Further, as other additives, for example, a coloring agent, a lubricant, a coupling agent, a fluidity improving material, an antioxidant, an ultraviolet absorber, a flame retardant, a stabilizer, an antistatic agent and the like may be blended. These additives may be used alone or in combination of two or more. These additives may be blended in the kneading step, or may be blended in advance with other components such as resin before the kneading step.

The amount of the additive added is not particularly limited, but for example, when the entire alloy resin composition is 100% by mass, the content of each additive is preferably about 0 to 5.0% by mass. Is added at a ratio of about 0.1 to 3.0% by mass, particularly about 0.5 to 2.0% by mass, and may be added at a ratio of 10.0% by mass or less as a whole of the additive. desired.

Of these, the ones considered to be important will be described below with examples, but the present invention is not limited to the ones exemplified below.

As the colorant, any known organic pigment, inorganic pigment or dye can be used. Specifically, organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindoleinone-based, geoosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments, ultramarine blue, titanium oxide, titanium yellow, and iron oxide. (Valve handle), chrome oxide, zinc flower, carbon black and other inorganic pigments can be mentioned.

As the antioxidant, a phosphorus-based antioxidant, a phenol-based antioxidant, and a pentaerythritol-based antioxidant can be used. Phosphorus-based, more specifically, phosphorus-based antioxidants such as phosphite ester and phosphoric acid ester are preferably used. Examples of the phosphorous acid ester include triphenyl phosphite, trisnonylphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, and other phosphorous acid triesters, diesters, and monoesters. Can be mentioned.

Examples of the phosphoric acid ester include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (nonylphenyl) phosphate, 2-ethylphenyldiphenyl phosphate and the like. These phosphorus-based antioxidants may be used alone or in combination of two or more.

Examples of phenolic antioxidants include α-tocopherol, butylhydroxytoluene, cinapyl alcohol, vitamin E, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2-. t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenylacrylate, 2,6-di-t-butyl-4- (N, N-dimethyl) Aminomethyl) phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, and tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane Etc. are exemplified, and these can be used alone or in combination of two or more kinds.

The flame retardant is not particularly limited, and for example, a halogen-based flame retardant or a non-phosphorus-based halogen-based flame retardant such as a phosphorus-based flame retardant or a metal hydrate can be used. Specific examples of the halogen-based flame retardant include halogenated bisphenol compounds such as halogenated bisphenyl alkane, halogenated bisphenyl ether, halogenated bisphenyl thioether, and halogenated bisphenyl sulfone, brominated bisphenol A, and bromine. Bisphenol-bis (alkyl ether) -based compounds such as bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S, and as phosphorus-based flame retardants, tris (diethylphosphinic acid) aluminum, bisphenol A bis (diphenyl phosphate) , Triaryl isopropyl phosphate, cresildi 2,6-xylenyl phosphate, aromatic condensed phosphate, etc., as metal hydrates, for example, aluminum trihydrate, magnesium dihydride, or a combination thereof. Etc. can be exemplified respectively, and these can be used alone or in combination of two or more kinds. Further, for example, antimony oxide such as antimony trioxide and antimony pentoxide, zinc oxide, iron oxide, aluminum oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide and the like can be used in combination as a flame retardant aid. ..

≪Manufacturing of alloy resin composition≫
The fiber contained in the mask of the present invention comprises an alloy resin composition obtained by kneading the above raw materials in a predetermined compounding ratio. The kneading method is not particularly limited and can be appropriately set according to the spinning method. For example, each raw material may be kneaded and melted before spinning, or the raw materials may be kneaded and melted at the same time by a molding machine in which a kneading device and a spinning device are integrated. In the melt kneading, it is preferable to knead by applying a high shear stress while uniformly dispersing each component, for example, it is preferable to knead with a twin-screw kneader.

When the above raw materials are kneaded and melted before spinning molding, the resin composition may be once molded in the form of pellets. In that case, the shape of the pellet is not particularly limited, and for example, a pellet such as a cylinder, a sphere, or an elliptical sphere can be used. The size of the pellet may be appropriately set according to the shape and the type of the spinning molding machine. For example, in the case of a spherical pellet, the diameter may be 1 to 10 mm. In the case of an elliptical spherical pellet, the pellet has an elliptical shape with an aspect ratio of 0.1 to 1.0, and may be 1 to 10 mm in length and width. In the case of cylindrical pellets, the diameter may be in the range of 1 to 10 mm and the length may be in the range of 1 to 10 mm.

In the production of the alloy resin composition, all the raw materials used can be kneaded at one time, but preferably a biodegradable resin component containing polylactic acid, the plasticizer such as lactic acid, and heavy calcium carbonate (No. 1). A biodegradable resin composition containing an optional component such as (2) inorganic substance powder), an olefin resin, a first inorganic substance powder, an ethylene polymer wax, and an olefin resin composition containing an optional component. Is prepared separately, and then both are preferably kneaded. For example, the pellets of the biodegradable resin composition prepared as described above and the pellets of the olefin-based resin composition can be spun at the same time as kneading and melting. Alternatively, both compositions may be kneaded once to prepare pellets of the alloy resin composition, which may be spun. Here, by adjusting the amount of heavy calcium carbonate in the biodegradable resin composition, it is possible to make the melt viscosity uniform with that of the olefin resin composition and improve the dispersion of both. By following these steps, the fibers contained in the mask can have sufficient physical properties such as strength.

Although the present invention is not limited by a specific theory, it is considered that the reason why the present invention is effective is that the biodegradable resin component and the olefin resin are well dispersed in the alloy resin composition. Biodegradable resins such as polylactic acid are generally inferior in compatibility with olefin resins, but by containing a plasticizer such as lactic acid or an ethylene polymer wax as in the present invention, both resins are melted. As the viscosity decreases, the compatibility also changes, and the melting and spinning characteristics also change due to the coexistence of inorganic substance powders such as heavy calcium carbonate particles. As a result, each resin component is uniformly finely dispersed and has excellent physical properties such as strength. It will be an alloy resin composition that gives fibers.

≪Fibers of alloy resin composition≫
By spinning the above resin composition, the fibers constituting the mask of the present invention can be obtained.

The spinning method is not particularly limited, but the melt spinning method is preferable, and a usual known method can be used. Since the resin composition having the above-mentioned structure is excellent in spinnability, it is possible to produce a desired fiber by using a general-purpose spinning device. For example, the cross-sectional shape of the fiber can be various shapes such as a polygonal shape such as a round shape, an elliptical shape, a triangular shape, a square shape, and a pentagonal shape, a star shape, and a hollow shape. Further, a composite fiber having a side-by-side, core-sheath structure containing resin compositions having different compositions or other types of resin compositions may be used as long as the object of the present invention is not impaired.

The average fiber diameter of the fibers can be arbitrarily set according to the target mask, but is preferably in the range of 0.1 to 30 μm. The average fiber diameter is more preferably 25 μm or less, and particularly preferably 20 μm or less. When it is about 20 μm or less, the fibers contained in the mask become sufficiently thin and can be particularly suitably used as a medical material. Further, when the average fiber diameter is, for example, 1 μm or more, particularly 10 μm or more, a fiber having excellent strength can be obtained.

≪Non-woven fabric≫
The fibers spun as described above may be woven by a weave such as plain weave, twill weave, satin weave, double weave, sha weave, and filter weave, but are preferably formed into a non-woven fabric. That is, the mask of the present invention is preferably composed of a non-woven fabric of fibers made of the above alloy resin composition. The non-woven fabric is not particularly limited and can be produced by various known methods. For example, the fiber made of the alloy resin composition may be made into a non-woven fabric by an electrostatic spinning method, a spunbond method, a melt blow method, a flash spinning method or the like. Fibers obtained from the above-mentioned alloy resin compositions of a plurality of types, for example, fibers made of an alloy resin composition containing heavy calcium carbonate particles and fibers made of an alloy resin composition free of heavy calcium carbonate are used in combination. You can also do it. Further, it can be combined with other fibers such as synthetic fibers, and for example, a plurality of types of fibers may be blended.

The shape of these non-woven fabrics is not particularly limited, but in order to secure sufficient collection efficiency and air permeability as a mask, it is preferable that the minimum pore diameter is 0.1 μm or less and the maximum pore diameter is more than 0.1 μm. More preferably, the minimum pore diameter is 0.01 to 0.1 μm, particularly 0.03 to 0.08 μm, and the maximum pore diameter is 0.2 to 1 μm, particularly 0.5 to 0.8 μm. The thickness is not particularly limited, and can be, for example, about 1 to 500 μm, or about 10 to 100 μm. In the mask of the present invention, a spunbonded non-woven fabric is preferable because it is easy to manufacture and convenient to use.

[Manufacturing method of non-woven fabric]
In the production of spunbonded non-woven fabrics, the spun fibers are directly processed into a sheet (web). Usually, the fibers of this web are combined to form a non-woven fabric. The basis weight of the non-woven fabric is not particularly limited, and can be a desired value according to the purpose. However, when a biodegradable resin composition containing heavy calcium carbonate particles is used, the fibers are highly filled with the inorganic substance powder, so that the texture is generally larger than that of a general-purpose non-woven fabric. For example, it can be in the range of 5 to ^{200 g / m 2} , especially 10 to 100 g / m ^{2, but is not limited thereto.}

The spunbond method is not particularly limited, and various known methods can be used. For example, the resin composition is spun from a spinning nozzle in advance, the spun long fiber filament is cooled by a cooling fluid or the like, and tension is applied to the filament by stretching air to obtain a predetermined fineness. Then, the obtained filaments can be collected on a moving collection belt and deposited to a predetermined thickness to form a spunbonded non-woven fabric.

It is preferable to combine and entangle the webs obtained as described above. This is a method of bonding between fibers constituting the web, and typical examples thereof include, but are not limited to, a chemical bonding method using a binder, a thermal bonding method, and a mechanical bonding method. Multiple methods can be used together. Binders used for chemical bonding include emulsions such as acrylic, vinyl, urethane, polyester, and butadiene, polyolefins, ethylene / vinyl acetate copolymers, low melting point polyamide resins, saturated polyester resins, and styrenes. Examples thereof include hot melt type powder resins such as butadiene copolymers. By penetrating these into the web, spraying, printing, etc., the fibers can be chemically bonded. A binder containing an epoxy group or the like may be used, and a curing agent such as melamine may be added to bond the binder. The heat bonding method includes a calendar method in which a web is passed through the joint of two thermal rolls, an air-through method in which hot air is sent from one of the webs, and ultrasonic bonding in which heat is generated in the fibers by high-frequency sound waves to melt the resin. Examples include the steam jet method, which injects high-temperature and high-pressure steam onto the web. Examples of the mechanical bonding method include a needle punching method in which a needle is pierced into a web to entangle the fibers, a water flow entanglement method in which the fibers are entangled with a high-pressure water stream, and a stitch bond method in which the webs are sewn together. A general method for producing a spunbonded non-woven fabric is a calendar method, which includes an area bond method (whole surface bonding method), a point bond method (point bonding method), an embossing method, and the like. In the present invention, the spunbonded nonwoven fabric can be produced by any of these methods. It is also possible to use multiple methods together.

Of the above, the most common bonding method is the embossing method, and also in the present invention, partial thermocompression bonding may be performed by embossing or the like. By thermocompression bonding, the strength of the spunbonded non-woven fabric can be improved, and the balance between flexibility and breathability can be improved. In the case of thermocompression bonding, the embossed area ratio (thermocompression bonding portion) is preferably 5 to 30%, particularly 7 to 20%. The engraved shape is also not limited, and can be, for example, a circle, an ellipse, an oval, a square, a rhombus, a square, a square, a quilt, a lattice, a turtle shell, or a continuous shape based on those shapes.

≪Electretization≫
The non-woven fabric produced as described above is then electretized and charged. The electretization treatment method is not particularly limited, and various known treatment methods can be adopted. For example, a method of applying an electric charge by friction or contact; a method of irradiating an active energy ray such as an electron beam, an ultraviolet ray, or an X ray; a method of utilizing a gas discharge such as a corona discharge or a plasma; a method of applying a high electric field; water. Examples thereof include, but are not limited to, a method in which ultrasonic vibration is applied via a polar liquid such as. However, a method of corona discharge treatment using a needle electrode or the like is preferable because a high charge can be easily applied. The conditions for corona discharge are also not particularly limited, and can be, for example, from room temperature to 100 ° C., particularly at a temperature of about 50 to 90 ° C. for 1 second to 1 minute, particularly about 5 to 30 seconds.

[Secondary processing of non-woven fabric]
The non-woven fabric may be subjected to secondary processing such as gear processing, printing, coating, laminating, heat treatment, shaping processing, hydrophilic processing, water repellent processing, and press processing. In particular, a non-woven fabric made of fibers containing heavy calcium carbonate particles and the like has a high whiteness and has an advantage that post-processing such as printing can be easily performed.

It is also possible to add antibacterial properties to the non-woven fabric. Examples of the method for imparting antibacterial properties include, but are not limited to, a method of applying a general-purpose antibacterial agent, a method of blending an antibacterial inorganic substance such as zeolite carrying silver ions with a resin composition, and spinning. ..

It is also possible to apply a processing treatment such as water repellency to the non-woven fabric. The water-repellent treatment makes it difficult for water, alcohol, oil, etc. to permeate, and even when alcohol is disinfected or blood or the like adheres, the barrier property is high. The water-repellent treatment can be performed, for example, by applying a processing agent such as a fluorine-based or silicone-based water-repellent agent, or by mixing the water-repellent agent with a resin raw material in advance as an additive to form a non-woven fabric. The adhesion amount (content) of the water repellent agent is preferably in the range of 0.5 to 10.0% by mass, particularly 1.0 to 5.0% by mass. It is also possible to perform processing such as repellent alcohol by the same method. There are no restrictions on the method of adhesion, for example, a method of spraying, a method of immersing in a processing agent bath and squeezing with a mangle, a method of coating, etc., and as a drying method, a method using a hot air dryer or a method using a tenter. , A method of contacting with a heating element, etc., but is not limited thereto.

Antistatic properties can be added to the non-woven fabric. By adding antistatic properties, the comfort of the mask can be improved. In addition, it can be made more suitable for use in factories and the like, especially in painting factories and the like where a large amount of solvent is used. Examples of the antistatic property-imparting method include a method of applying an antistatic property-imparting agent such as a fatty acid ester or a quaternary ammonium salt, or a method of mixing with a resin raw material as an additive to form a non-woven fabric. Not limited to these. By such a method, the antistatic property of the non-woven fabric can be set to 1000 V or less by the cotton cloth friction method shown in the JIS L1094C method in an atmosphere of, for example, 20 ° C. and 40% RH.

≪Manufacturing of mask≫
The biodegradable non-woven fabric mask of the present invention is composed of at least a part, usually a part or all of a covering part which is a main part, of the fibrous non-woven fabric produced as described above. The biodegradable non-woven fabric mask of the present invention can be obtained by attaching an ear hook member, a band member, or the like to the covering portion containing the non-woven fabric produced as described above. The shape of the mask is not particularly limited, and any shape such as a flat type, a cup type, and a foldable type can be adopted. There is no limitation on the size, and for example, the perforated area of the covering portion can be set ^{to about 100 to 300 cm 2 according to the user and the purpose of use.}

In the biodegradable non-woven fabric mask of the present invention, the covering portion may be composed of one of the above-mentioned non-woven fabrics, but is preferably formed by laminating a plurality of non-woven fabrics. When laminating a plurality of non-woven fabrics, the same type may be used, but different kinds of non-woven fabrics may be laminated. Other general-purpose fibers, woven fabrics, non-woven fabrics, porous polymer films, and the like may be laminated. In the case of laminating, a plurality of non-woven fabrics and the like may be simply laminated, but these may be sewn or heat-sealed to be integrated. For example, a fiber made of a biodegradable resin composition may be sandwiched between two general-purpose non-woven fabrics that are not biodegradable. Alternatively, it is also possible to laminate the biodegradable non-woven fabric produced as described above with another cloth, a porous polymer film, or the like to obtain a mask having special filter performance.

However, in the biodegradable non-woven fabric mask of the present invention, it is preferable that most of the covering portion, for example, 90% or more in area, is composed of the biodegradable non-woven fabric as described above. Even if the non-woven fabric made of an alloy resin composition containing heavy calcium carbonate particles as the second inorganic substance powder and the non-woven fabric made of an alloy resin composition containing no heavy calcium carbonate particles are laminated to form a structure. good. With such a structure, it is possible to obtain a biodegradable non-woven fabric mask that has both antifungal and antibacterial properties due to the inclusion of heavy calcium carbonate particles and flexibility and wearability due to the absence of heavy calcium carbonate particles. can.

The mask of the present invention is flexible, has high rigidity, has excellent shape retention, and is easy to manufacture. In addition, since the main raw material is alloy resin based on biodegradable resin and a large amount of inorganic substance powder is filled, the amount of waste plastic is significantly reduced even when it is discarded, which can contribute to environmental conservation. Therefore, for hygienic reasons, it is suitable as a mask used as a disposable material. In particular, a mask containing fibers filled with heavy calcium carbonate particles and the like is suitable for use as a living material that requires fashionability because post-processing such as printing is easy.

Hereinafter, the present invention will be described in more detail based on Examples. It should be noted that these examples are specific embodiments and practices in order to facilitate understanding of the concept and scope of the present invention disclosed in the present specification and described in the appended claims. The present invention is described only for the purpose of exemplifying the embodiments, and the present invention is not limited to these examples.

[Example 1]
PolyL-lactic acid was used as a biodegradable resin component, and polypropylene was used as an olefin resin, and spunbonded non-woven fabric was prepared by kneading and spinning with the following various raw materials.
-Poly L-lactic acid: manufactured by Nature Works LLC, weight average molecular weight 100,000-200,000
-Polypropylene: Propylene homopolymer manufactured by Japan Polypropylene Corporation: Novatec (registered trademark) BC06C, melt flow rate 60 g / 10 minutes, density 0.900 g / cm ³
-Lactic acid oligomer: Trade name "CPL" manufactured by Ractive Japan Co., Ltd., weight average molecular weight: 3,000 or less-Ethylene polymer wax: Excelex (registered trademark) 30200B manufactured by Mitsui Chemicals, Inc., weight average molecular weight 2900 , Density 0.913 g / cm ³ , melting point 102 ° C, softening point 105 ° C
-Calcium carbonate: heavy calcium carbonate particles, average particle size: 2.2 μm, BET specific surface area: 1.0 m ² / g, roundness: 0.85
-Antistatic agent: Diethanolamide laurate-Antioxidant: Pentaerythritol Tetrakis [3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate]

97 parts by mass of poly L-lactic acid, 200 parts by mass of heavy calcium carbonate particles, and 3 parts by mass of lactic acid oligomer are kneaded at 190 ° C. using a biaxial kneading extruder (φ25 mm, L / D = 41) rotating in the same direction. , Extruded into water with strands, cooled and cut to prepare pellet-1. Under the same conditions, 40 parts by mass of polypropylene, 60 parts by mass of heavy calcium carbonate particles, and 1 part by mass of ethylene-based polymer wax were kneaded to prepare pellet-2.
Next, 300 parts by mass of pellet-1 and 101 parts by mass of pellet-2 were mixed and introduced into a twin-screw kneading extruder to perform melt spinning at 190 ° C. After depositing the obtained fibers on the collecting surface, a spunbonded nonwoven fabric having a fiber diameter of 10 μm and a basis weight of 20 g / m ^{2 was produced by thermal embossing.}

The produced spunbonded non-woven fabric was cut into a size of 180 × 150 mm, and electretized for 20 seconds with a corona discharge surface modifier manufactured by Shinko Denki Keiso Co., Ltd. After stacking three non-woven fabrics of the same type and suturing the peripheral portion of the long side, folding portions extending in the longitudinal direction were provided at three locations near the central portion. Ear hooks were attached to the periphery of both short sides and sutured to prepare a mask having a size of 180 × 90 mm. Five masks were prepared, each of which was tried on by five monitors, and the following performance was evaluated.
[Performance evaluation items]
-Flexibility: Each monitor was made to judge whether it was hard and stiff.
-Wearability: Each monitor was asked to judge whether there was any ventilation or leakage from the peripheral part and whether the mask fits even if the mouth is moved.
-Wearing feeling: Each monitor was made to judge whether there was any discomfort such as slippage due to bleeding of monomers or oligomers and irritation due to fluffing of fibers.
Table 1 shows the results of the monitor evaluations for the above evaluation items together with the formulation. In each evaluation item, the sample evaluated by all 5 monitors as good is marked with ◎, the sample judged by 4 people as good is marked with 〇, and the sample judged by 3 people as good is marked with △, and the majority of the monitors feel a problem. The sample was displayed as x.

[Examples 2 to 3 and Comparative Examples 1 to 5]
The blending ratios of various raw materials were changed as shown in Table 1, and masks were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 together with the formulation. In Table 1, the unit of the blending ratio is "parts by mass". For calcium carbonate, the blending ratio (P1) in pellet-1 and the blending ratio (P2) in pellet-2 are shown together with the total amount of both, and the total amount is shown in parentheses. Further, since the antistatic agent and the antioxidant are blended in 3.0 parts by mass in each of the Examples and Comparative Examples, the description is omitted in Table 1. The plasticizer DOP used in Comparative Example 4 is di (2-ethylhexyl) phthalate manufactured by Daihachi Chemical Industry Co., Ltd.

As is clear from Table 1, a mask composed of fibers containing a specified amount of polylactic acid, an olefin resin, an inorganic substance powder, a plasticizer such as lactic acid, and an ethylene polymer wax according to the present invention is flexible and can be worn. It was excellent in sex and fit. On the other hand, in Comparative Example 1 using fibers containing no plasticizer and ethylene-based polymer wax, the obtained non-woven fabric was brittle, and a mask that could withstand the evaluation could not be produced. Not only was it inflexible, but it also seemed to be partially damaged during bending due to insufficient strength. It is thought to be due to poor dispersion of polylactic acid and polypropylene in the fiber. The masks of Comparative Examples 2 and 3 produced by using only one of the plasticizer and the ethylene-based polymer wax-free were also lacking in flexibility and were inferior in wearability and fit. In the mask of Comparative Example 5 in which DOP, which is a general-purpose plasticizer, was used instead of these plasticizers, the flexibility was moderately improved and the fit was also moderately evaluated. The majority of monitors complained of discomfort. Further, in the mask of Comparative Example 5 in which the content of the inorganic substance powder was low, the wearability was not so high, and discomfort regarding the touch of the mask was also complained. Further, when the masks were produced in Comparative Example 1 and Comparative Example 5, the non-woven fabric was slightly shrunk by the corona treatment. No such shrinkage was observed in the examples, demonstrating the effect of the fibers having a composition according to the present invention.

[Example 4, Comparative Examples 6 to 7]
A capture test of microsilica was carried out using a non-woven fabric having a size of 180 × 150 mm prepared at the time of mask preparation in Example 1. Weigh 50 g of microsilica (average particle diameter: about 0.15 μm) manufactured by Elkem into a 300 ml beaker (diameter about 100 mm), insert a glass tube from above, cover the beaker with the above-mentioned non-woven fabric, and use a rubber band around it. Fixed. Next, nitrogen gas was flowed from the bottom of the beaker at a flow rate of 100 ml / min for 10 minutes through a glass tube, and microsilica was scattered in the form of smoke. After 10 minutes, the non-woven fabric was removed, placed in ethanol and subjected to ultrasonic cleaning for 15 minutes. The washed ethanol was evaporated to dryness, and the weight of the residual solid content was measured and used as the captured microsilica amount (A). On the other hand, the weight of the microsilica remaining in the beaker was measured, and the difference from the weight before the test was used as the scattered amount of microsilica (B). Table 2 shows the results (Example 4) of calculating the capture rate by the non-woven fabric as A / B × 100.
A similar test was also performed on the non-woven fabric before electretization treatment prepared at the time of mask production in Example 1 (Comparative Example 6). Further, a non-woven fabric produced in the same manner from only pellet-1 in Example 1 and subjected to electretization treatment was also tested in the same manner (Comparative Example 7). These results are shown in Table 2.

As shown in Table 2, the non-woven fabric made of an alloy resin composition having a composition according to the present invention was greatly improved in the capture rate of fine particles by the electretization treatment. On the other hand, the non-woven fabric containing only polylactic acid as a resin component (Comparative Example 7) was inferior to the non-woven fabric of Example 4 in the capture rate even after being electretized. Further, the non-woven fabric of Comparative Example 7 shrank to some extent during the electretization treatment (corona treatment). The difference in the effect depending on the presence or absence of the olefin resin blend on the biodegradable resin was also shown from these Examples and Comparative Examples.

Claims (10)

A biodegradable non-woven fabric mask containing at least a part of an electretized non-woven fabric made of fibers made of an alloy resin composition.
The alloy resin composition
Biodegradable resin component containing polylactic acid,
Olefin resin,
A plasticizer selected from the group consisting of lactic acid, a lactic acid oligomer having a weight average molecular weight of 3,000 or less, and branched polylactic acid.
Contains inorganic substance powder and ethylene polymer wax with a weight average molecular weight of 400 or more and 5,000 or less.
The plasticizer is contained in a proportion of 1 to 5% by mass when the total mass of the plasticizer and the biodegradable resin component is 100%.
The olefin resin and the inorganic substance powder are contained in a mass ratio of 50:50 to 10:90, and the ethylene polymer wax contains a total amount of 100 of the olefin resin and the inorganic substance powder. A biodegradable non-woven fabric mask containing 0.1 parts by mass or more and 3.0 parts by mass or less with respect to parts by mass. Claim 1 in which the biodegradable resin component contains poly-L-lactic acid having a weight average molecular weight (Mw) of 50,000 or more and 300,000 or less in a proportion of 10 to 100% by mass of the total biodegradable resin component. The biodegradable non-woven fabric mask described in. Claim 1 or 2 in which the olefin-based resin contains a polypropylene-based resin, and the polypropylene-based resin is a polypropylene homopolymer having a melt flow rate (MFR) of 50 g / 10 minutes or more and 70 g / 10 minutes or less. The biodegradable non-woven fabric mask described in. The ethylene density of the polymer wax, 0.890 g / cm ³ or more 0.990 g / cm ³ or less biodegradable nonwoven mask according to any one of claims 1 to 3. The invention according to any one of claims 1 to 4, wherein the inorganic substance powder is heavy calcium carbonate particles having an average particle diameter of 1.0 μm or more and 5.0 μm or less by an air permeation method according to JIS M-8511. Biodegradable non-woven mask. The biodegradation according to claim 5, wherein the BET specific surface area of the heavy calcium carbonate particles is 0.1 m ² / g or more and 10.0 m ² / g or less, and the roundness is 0.50 or more and 0.95 or less. Sex non-woven mask. The alloy resin composition further contains heavy calcium carbonate particles as a second inorganic substance powder.
The content of the second inorganic substance powder is 50% by mass or more and 90% by mass or less when the total mass of the second inorganic substance powder, the biodegradable resin component, and the plasticizer is 100%. Is the ratio of
The average particle size calculated from the measurement result of the specific surface area of the second inorganic substance powder by the air permeation method according to JIS M-8511 is 1.0 μm or more and 10.0 μm or less, and
The biodegradable non-woven fabric mask according to any one of claims 1 to 6, wherein the BET specific surface area of the second inorganic substance powder is 0.1 m ² / g or more and 10.0 m ^{2 / g or less.} The biodegradable non-woven fabric mask according to claim 7, wherein the roundness of the second inorganic substance powder is 0.50 or more and 0.95 or less. The method for producing a biodegradable non-woven fabric mask according to any one of claims 1 to 8.
Including the step of producing the alloy resin composition.
The step is
A step of producing a biodegradable resin composition by mixing the biodegradable resin component and the plasticizer.
A step of mixing the olefin resin, the inorganic substance powder, and the ethylene polymer wax to produce an olefin resin composition, and the biodegradable resin composition and the olefin resin composition. A method for producing a biodegradable non-woven plastic mask, which comprises a step of mixing. When the inorganic substance powder is used as the first inorganic substance powder,
In the step of producing the biodegradable resin composition,
The method for producing a biodegradable non-woven fabric mask according to claim 9, wherein the biodegradable resin component, the plasticizer, and a second inorganic substance powder are mixed to produce the biodegradable resin composition. ..