Polyethylene resin composition, melt-blown nonwoven fabric using polyethylene resin, and electret material

Abstract

Provided is a resin composition having excellent productivity and little environmental burden. The resin composition according to the present invention comprises a polyethylene resin, a polypropylene resin, and a compatibilizing agent, and is characterized in that the polyethylene resin comprises a plant-derived polyethylene resin.

Description

Technical Field

[0001] The present invention relates to a polyethylene resin composition, and more particularly to a melt-blown nonwoven fabric, an electret material, and a method for producing the electret material using the polyethylene resin composition. Background Art

[0002] It is known that nonwoven fabrics made of polyethylene fibers are soft and have a good touch. However, polyethylene fibers are generally difficult to spin by melt-blowing. In addition, in order to reduce the fiber diameter, the spinning temperature needs to be increased, but in this case, gelation due to a cross-linking reaction occurs. Therefore, in conventional polyethylene melt-blown nonwoven fabrics, the fiber diameter is large and the texture is poor.

[0003] Therefore, it is considered to use only polyethylene with a molecular weight lower than that of general-purpose polyethylene resins, such as polyethylene wax, to form fibers with a fine fiber diameter and melt-blown nonwoven fabrics. However, although these low-molecular-weight polyethylenes have good spinnability, the resulting fibers are weak in strength and have a lot of fuzz, making it difficult to continuously produce a web.

[0004] In order to solve the above-mentioned problems, the following method is disclosed: a resin composition comprising a polyethylene (A) having a weight average molecular weight of 21,000 to 45,000 and a melt flow rate of 15 to 250 g / 10 min and a polyethylene wax (B) having a weight average molecular weight of 12,000 or less is used in a ratio (A) / (B) of 70 / 30 to 30 / 70 to obtain a polyethylene nonwoven fabric formed by a melt-blown method (Patent Document 1).

[0005] On the other hand, petroleum-based synthetic fibers and petroleum-based plastic resins including polyolefins such as polypropylene and polyethylene are difficult to decompose, so garbage disposal issues have become a major obstacle in practicing a recycling-oriented society, and the carbon dioxide produced during incineration has become a cause of global warming. In addition, since the raw materials come from petroleum, there is a concern about the depletion of fossil resources. Under such circumstances, resin films, non-woven fabrics, etc. are also required to be replaced and their usage reduced.

[0006] Therefore, in the field of resin films, in order to reduce the load on the environment, it has been reported that a part of the raw materials of the resin films are replaced from petroleum-derived resins to plant-derived resins (Patent Document 2).

[0007] Patent document 2 states that plant-derived resins have no change in chemical structure from conventional petroleum-derived resins and are expected to have equivalent physical properties. However, in reality, resin films containing plant-derived resins, such as sealing films containing plant-derived polyethylene resins, exhibit properties different from those of sealing films containing only petroleum-derived polyethylene resins.

[0008] In recent years, electret materials using polyethylene resins have been studied.

[0009] In the past, materials called electrets were widely used. Electrets are a series of materials that can maintain and utilize electrostatic force without continuously supplying external energy by performing various operations on various dielectric materials. Electrets use electrostatic force to the outside world and are used for microphones, sensors, generators, and various protection and separation purposes.

[0010] In the above-mentioned separation and protection purposes, in addition to using in a planar form such as a membrane, there is also a known method of improving functionality by combining with the separation and filtration purposes of the porous material itself. For example, filters using fibrous materials have advantages such as high porosity, long life, and low ventilation resistance, and are therefore widely used. Filters containing these fibrous materials capture particles on the fibers through mechanical capture mechanisms such as blocking, diffusion, and inertial collision, but it is known that in a practical use environment, the aerodynamic equivalent diameter of the captured particles is about 0.1 to 1.0 μm, and the filter capture efficiency is minimal. An electret filter is used that utilizes the electrostatic attraction of the electret to compensate for its weakness.

[0011] In order to improve the collection efficiency of the electret filter, it is known that it is preferable to give electrostatic charge to the fibrous material by a method of bringing a liquid into contact or collision with the fibrous material (liquid contact charging method) to form an electret. For example, as an electret that takes both cost and performance into consideration, there is known an electret in which electrostatic charge is given by bringing a liquid such as water into contact with a fibrous material, the fibrous material being formed by adding a nitrogen-containing compound such as a hindered amine compound to a resin having a polyolefin resin as a main component.

[0012] In the past, polytetrafluoroethylene, polypropylene, polyvinylidene fluoride, etc. are known as polymer resins that can be used as electret materials. However, even if polyethylene is charged, the charge escapes and is not retained, and it is not very useful as an electret. Therefore, a method of adding a modified polyethylene resin graft-copolymerized with an unsaturated carboxylic acid to a polyethylene resin to improve the charging characteristics and make it easy to charge and make an electret, and a method of adding an ethylene-based random copolymer have been proposed (Patent Document 3).

[0013] In addition, polypropylene or the like used as an electret material may be mixed with polyethylene. However, although polypropylene and polyethylene are classified as the same polyolefin-based material, they are incompatible materials, and it is known that it is technically difficult to mix and composite them without inducing phase separation.

[0014] Prior art literature

[0015] Patent Literature

[0016] Patent Document 1: Japanese Patent No. 3995885

[0017] Patent Document 2: Japanese Patent Application Publication No. 2018-052120

[0018] Patent Document 3: Japanese Patent Application Laid-Open No. 10-308326 Summary of the invention

[0019] Problems to be solved by the invention

[0020] In the field of nonwoven fabrics, the reduction of environmental load has also been studied, but referring to Patent Document 2, it is known that when a nonwoven fabric is to be obtained by using a polyethylene resin derived from plants and by the method of Patent Document 1, a fine-fine melt-blown nonwoven fabric cannot be obtained. That is, the current situation is that when a polyethylene resin derived from plants is used, the productivity is low in the conventionally known method for producing nonwoven fabrics, and a fine-fine melt-blown nonwoven fabric cannot be obtained.

[0021] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a resin composition that contributes to reducing environmental load and improving productivity.

[0022] As one of the preferred embodiments, a melt-blown nonwoven fabric using a polyethylene resin is provided, which has a fine fineness, is excellent in productivity, and has a low environmental load, which cannot be achieved by conventionally known methods (hereinafter referred to as the first problem).

[0023] In addition, the electret material using polyethylene resin, which is one of the preferred embodiments of the present invention, has the following problems.

[0024] The manufacturing cost of modified polyethylene resin is high and it is not widely used. In addition, although relatively good results were obtained in the system using only ethylene random copolymers, the system in which ethylene random copolymers were added to polyethylene resins showed a decrease in electret performance, and there are problems with the electret performance of polyethylene resins. In addition, in the field of electrets, in order to reduce the load on the environment, it is also required to replace part of the raw materials from petroleum-derived resins with plant-derived resins.

[0025] Therefore, an object of a preferred embodiment of the present invention is to provide a novel electret material using a polyethylene resin, which has excellent productivity and electret performance that cannot be achieved by conventionally known methods and has a small environmental load (hereinafter referred to as the second problem).

[0026] Furthermore, in the electret material, the following solutions to the problems are also known.

[0027] The conventionally known electret materials using polyethylene resins have the problem of low charge stability. In addition, the electrostatic force, i.e., the charge, maintained by the electret material may decay due to heat treatment during processing. In addition, in the field of electrets, in order to reduce the load on the environment, it is also required to replace part of the raw materials from petroleum-derived resins with plant-derived resins.

[0028] Therefore, another object of a preferred embodiment of the present invention is to provide a novel electret material using a polyethylene resin, which has excellent charge stability that cannot be achieved by conventionally known methods and has a small environmental load (hereinafter referred to as the third problem).

[0029] Means for solving problems

[0030] The present inventors have conducted intensive studies on the above-mentioned problems and have found that a polyethylene resin having the following structure is useful for solving the above-mentioned problems, and is particularly useful for solving the above-mentioned problems in melt-blown nonwoven fabrics and electret materials.

[0031] 1. A resin composition comprising a polyethylene resin, a polypropylene resin and a compatibilizer, wherein the polyethylene resin comprises a plant-derived polyethylene resin.

[0032] 2. The resin composition according to 1 above, further comprising a nitrogen-containing compound.

[0033] 3. The resin composition according to 1 above, further comprising a nitrogen-containing compound and a fatty acid metal salt.

[0034] 4. The resin composition according to any one of 1 to 3 above, comprising 0.1 to 20% by mass of the compatibilizer based on 100% by mass of the resin composition.

[0035] 5. The resin composition according to the above 2, wherein the nitrogen-containing compound is contained in an amount of 0.1 to 5% by mass based on 100% by mass of the resin composition.

[0036] 6. The resin composition according to item 3 above, comprising 0.1 to 5% by mass of the nitrogen-containing compound and 0.01 to 1% by mass of the fatty acid metal salt relative to 100% by mass of the resin composition.

[0037] 7. The resin composition according to any one of 1 to 3 above, comprising 10 to 98% by mass of the polyethylene resin based on 100% by mass of the resin composition.

[0038] 8. The resin composition according to any one of 1 to 3 above, wherein the compatibilizer is present in at least one of the polyethylene resin and the polypropylene resin.

[0039] 9. The resin composition according to 2 or 3 above, wherein the nitrogen-containing compound includes a hindered amine compound.

[0040] 10. A melt-blown nonwoven fabric using the resin composition described in 1 above.

[0041] 11. The melt-blown nonwoven fabric according to 10 above, wherein the average fiber diameter of fibers constituting the nonwoven fabric is 8 μm or less.

[0042] 12. An electret material using the resin composition described in 2 or 3 above.

[0043] 13. The electret material according to 12 above, wherein the electret material is a sheet-like object.

[0044] 14. The electret material according to 13 above, wherein the sheet-like material is a meltblown nonwoven fabric or a spunbonded nonwoven fabric.

[0045] 15. The electret material according to 14 above, which is charged by contact with a liquid.

[0046] 16. An electret filter using the electret material described in 14 above.

[0047] 17. An electret filter material using the electret filter according to 16 above, wherein a performance maintenance rate obtained by dividing a value obtained by the following filter material quality factor (QF) after a heat load of 100° C. is applied to the filter material by a value obtained by the following filter material quality factor (QF) before a heat load of 100° C. is 0.75 or more.

[0048] QF[mmAq -1 ]=-[ln(1-(particle collection efficiency (%) / 100))] / [ventilation resistance (mmAq)]

[0049] 18. A method for producing an electret material, comprising the step of melt-mixing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound.

[0050] 19. A method for producing an electret material, comprising the step of melt-mixing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound, and a fatty acid metal salt.

[0051] Regarding the present invention described above, preferred configurations corresponding to the first to third problems are as follows.

[0052] The present inventors have conducted intensive research on the first problem and have found that a melt-blown nonwoven fabric having a fine fineness, excellent productivity and low environmental load can be obtained by containing a polyethylene resin, a polypropylene resin and a compatibilizer and manufacturing by a melt-blowing method, thereby completing the present invention. That is, the present invention that solves the first problem preferably has the following configuration (hereinafter referred to as the first embodiment).

[0053] 1-1. A melt-blown nonwoven fabric, comprising a polyethylene resin, a polypropylene resin and a compatibilizer, wherein the polyethylene resin comprises a plant-derived polyethylene resin.

[0054] 1-2. The melt-blown nonwoven fabric according to 1-1 above, wherein the compatibilizer is contained in an amount of 0.1 to 20% by mass based on 100% by mass of the melt-blown nonwoven fabric.

[0055] 1-3. The melt-blown nonwoven fabric according to 1-1 or 1-2 above, wherein the polyethylene resin is contained in an amount of 10 to 98% by mass based on 100% by mass of the melt-blown nonwoven fabric.

[0056] 1-4. The melt-blown nonwoven fabric according to any one of 1-1 to 1-3 above, wherein the compatibilizer is present in at least one of the polyethylene resin and the polypropylene resin.

[0057] Here, in the melt-blown nonwoven fabric of the present invention, the compatibilizer may be present at the interface of either the polyethylene resin or the polypropylene resin, or may be present at the interface of both.

[0058] 1-5. The melt-blown nonwoven fabric according to any one of 1-1 to 1-4 above, wherein the average fiber diameter of fibers constituting the nonwoven fabric is 8 μm or less.

[0059] In addition, the present inventors have conducted intensive studies on the second problem and have found that an electret material containing a polyethylene resin at least partially containing a polyethylene resin derived from a plant, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound has excellent productivity and electret performance and a small environmental load, thereby completing the present invention. That is, the present invention that solves the second problem preferably has the following configuration (hereinafter referred to as the second embodiment).

[0060] 2-1. An electret material, comprising a polyethylene resin, a polypropylene resin, a compatibilizer and a nitrogen-containing compound, wherein the polyethylene resin is derived from a plant.

[0061] 2-2. The electret material according to 2-1 above, comprising 80% by mass or more of polyethylene resin and polypropylene resin, 0.1 to 20% by mass of a compatibilizer, and 0.1 to 5% by mass of a nitrogen-containing compound, based on 100% by mass of the electret material, and comprising a plant-derived polyethylene resin.

[0062] 2-3. The electret material according to 2-1 or 2-2 above, wherein the polyethylene resin accounts for 10% to 98% by mass based on 100% by mass of the electret material.

[0063] 2-4. The electret material according to any one of 2-1 to 2-3 above, wherein the compatibilizer is present in at least one of the polyethylene resin and the polypropylene resin.

[0064] 2-5. The electret material according to any one of 2-1 to 2-4, wherein the nitrogen-containing compound includes a hindered amine compound.

[0065] 2-6. The electret material according to any one of 2-1 to 2-5 above, which is a sheet-shaped article.

[0066] 2-7. The electret material according to 2-6 above, wherein the sheet-like material is a meltblown nonwoven fabric or a spunbonded nonwoven fabric.

[0067] 2-8. The electret material according to any one of 2-1 to 2-7 above, characterized in that it is charged by contact with a liquid.

[0068] 2-9. An electret filter using the electret material described in any one of 2-1 to 2-8 above.

[0069] 2-10. A method for producing an electret material, comprising the step of melt-mixing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound.

[0070] In addition, the present inventors have conducted intensive studies on the third problem and have found that an electret material containing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound, and a fatty acid metal salt has excellent productivity and electret performance and a small environmental load, thereby completing the present invention. That is, the present invention preferably has the following configuration (hereinafter referred to as the third embodiment).

[0071] 3-1. An electret material, comprising a polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound and a fatty acid metal salt, wherein the electret material comprises a polyethylene resin derived from a plant.

[0072] 3-2. The electret material according to 3-1 above, characterized in that it contains 80% by mass or more of a polyethylene resin and a polypropylene resin, 0.1 to 20% by mass of a compatibilizer, 0.1 to 5% by mass of a nitrogen-containing compound, and 0.01 to 1% by mass of a fatty acid metal salt, based on 100% by mass of the electret material, and contains a plant-derived polyethylene resin.

[0073] 3-3. The electret material according to 3-1 or 3-2 above, wherein the performance maintenance rate represented by the value obtained by dividing the QF value after applying a heat load of 100° C. by the QF value before applying a heat load of 100° C., which is a filter quality factor (QF) value represented by the following formula, is 0.75 or more.

[0074] QF[mmAq -1 ]=-[ln(1-(particle collection efficiency (%) / 100))] / [ventilation resistance (mmAq)]

[0075] 3-4. The electret material according to any one of 3-1 to 3-3 above, wherein the polyethylene resin accounts for 10% by mass to 98% by mass based on 100% by mass of the electret material.

[0076] 3-5. The electret material according to any one of 3-1 to 3-4 above, wherein the compatibilizer is present in at least one of the polyethylene resin and the polypropylene resin.

[0077] 3-6. The electret material according to any one of 3-1 to 3-5 above, wherein the nitrogen-containing compound includes a hindered amine compound.

[0078] 3-7. The electret material according to any one of 3-1 to 3-6 above, which is a sheet-shaped article.

[0079] 3-8. The electret material according to 3-7 above, wherein the sheet-like material is a meltblown nonwoven fabric or a spunbonded nonwoven fabric.

[0080] 3-9. The electret material according to any one of 3-1 to 3-8 above, characterized in that it is charged by contact with a liquid.

[0081] 3-10. An electret filter using the electret material described in any one of 3-1 to 3-9 above.

[0082] 3-11. A method for producing an electret material, comprising the step of melt-mixing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound, and a fatty acid metal salt.

[0083] Effects of the Invention

[0084] According to the resin composition of the present invention, the above-mentioned problems can be solved. Specific effects corresponding to each embodiment are as follows.

[0085] According to the first embodiment of the present invention, it is possible to provide a melt-blown nonwoven fabric having a fine fineness that cannot be achieved with polyethylene resin alone, excellent productivity, and low environmental load.

[0086] In addition, according to the second embodiment which is a preferred embodiment of the present invention, an electret material and an electret filter having high productivity and electret performance which cannot be achieved by polyethylene resin alone and having a small environmental load can be provided. In particular, if the electret material is a melt-blown nonwoven fabric, an electret material of a melt-blown nonwoven fabric having a fine fineness, excellent productivity and a small environmental load can be provided.

[0087] Furthermore, according to the third embodiment which is a preferred embodiment of the present invention, an electret material and an electret filter having high charge stability and low environmental load which cannot be achieved with polyethylene resin can be provided. In particular, if the electret material is a melt-blown nonwoven fabric, an electret material of a melt-blown nonwoven fabric having a fine fineness, excellent productivity, and low environmental load can be provided. DETAILED DESCRIPTION

[0088] The present invention will be described in detail below, but the present invention is not limited to the following contents and can be implemented with appropriate modifications within the scope consistent with the gist, and all of these are included in the technical scope of the present invention.

[0089] The resin composition of the present invention comprises a polyethylene resin, a polypropylene resin and a compatibilizer, wherein the polyethylene resin comprises a plant-derived polyethylene resin.

[0090] The melt-blown nonwoven fabric of the first embodiment of the present invention comprises a polyethylene resin, a polypropylene resin and a compatibilizer, and at least a part of the polyethylene resin is derived from plants. In addition, a melt-blown nonwoven fabric comprising a polyethylene resin, a polypropylene resin and a compatibilizer is also a preferred embodiment.

[0091] The electret material of the second embodiment of the present invention further contains a nitrogen-containing compound in the meltblown nonwoven fabric of the first embodiment. That is, the electret material of the second embodiment contains a polyethylene resin, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound, and at least a part of the polyethylene resin is derived from plants. In addition, the electret material containing a polyethylene resin, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound is also a preferred embodiment.

[0092] In addition, the electret material of the third embodiment of the present invention further comprises a fatty acid metal salt in the electret material of the second embodiment. That is, the electret material of the third embodiment comprises a polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound and a fatty acid metal salt, and at least a part of the polyethylene resin is derived from plants. In addition, an electret material comprising a polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound and a fatty acid metal salt is also a preferred embodiment.

[0093] Hereinafter, the resin composition of the present invention and materials common to the first embodiment, the second embodiment, and the third embodiment will be described.

[0094] <Polyethylene resin>

[0095] In the present invention, the content of the polyethylene resin is preferably 10 to 98% by mass, more preferably 20 to 95% by mass, and even more preferably 30 to 90% by mass, relative to 100% by mass of the resin composition, that is, relative to 100% by mass of the total of the polyethylene resin, the polypropylene resin and the compatibilizer.

[0096] In the first embodiment, the content of the polyethylene resin is a ratio relative to 100 mass % of the melt-blown nonwoven fabric, that is, a total of 100 mass % of the polyethylene resin, the polypropylene resin, and the compatibilizer.

[0097] In the second embodiment, the preferred content ratio of each of the polyethylene resins is a ratio relative to 100 mass % of the electret material, that is, 100 mass % of the total of the polyethylene resin, the polypropylene resin, the compatibilizer, and the nitrogen-containing compound.

[0098] In the third embodiment, the preferred content ratio of the polyethylene resin is 100 mass % relative to 100 mass % of the electret material, that is, 100 mass % of the total of the polyethylene resin, the polypropylene resin, the compatibilizer, the nitrogen-containing compound and the fatty acid metal salt.

[0099] As for the polyethylene resin used in the present invention, as the homopolymer of ethylene, any kind in high pressure process low density polyethylene, linear low density polyethylene, high density polyethylene can be preferably used. In addition, it can also be the copolymer formed by ethylene and other monomers. The copolymer can be a random copolymer or a block copolymer.

[0100] <Plant-derived polyethylene resin>

[0101] The polyethylene resin used in the present invention is characterized by containing 1 to 100% by mass of a plant-derived polyethylene resin, more preferably 20 to 100% by mass, further preferably 50 to 100% by mass, most preferably 80 to 100% by mass, and it is also preferred to contain only plant-derived polyethylene. "Derived from plants" in the present invention means containing carbon derived from plant raw materials. In the case of a mixture with a fossil-derived raw material, it can be calculated based on the carbon ratio contained in the total polyethylene.

[0102] In the present invention, at least a part of the carbon atoms of the plant-derived polyethylene resin is derived from plant raw materials. The plant-derived polyethylene resin is a homopolymer of ethylene containing carbon derived from plants, or a copolymer with a comonomer containing carbon derived from plants. Specifically, examples include: high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and mixtures thereof, obtained by polymerizing ethylene derived from bioethanol.

[0103] As the α-olefins that are comonomers for the above LLDPE, examples include: α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene, etc., and mixtures thereof. These α-olefins can be plant-derived α-olefins derived from bioethanol, or non-plant-derived, i.e., petroleum-derived α-olefins. Since a wide variety of α-olefins can be obtained as petroleum-derived α-olefins, by using them in manufacturing, it is possible to easily adjust the physical properties of the polyethylene resin, etc. By using plant-derived α-olefins, the biomass degree of the final product can be further improved.

[0104] There is no particular limitation on the raw materials for plant-derived ethylene and plant-derived α-olefins. Vegetable oil, food waste, wood, paper, various celluloses, and sugars can be used as raw materials. As the raw material for the plant ethylene used in the present invention, sugarcane, corn, and sweet potato are preferred, and sugarcane is particularly preferred. As an example of the manufacturing method, according to a conventional method, a sugar solution or starch obtained from plants such as sugarcane, corn, sweet potato, beet, cassava, and sugar beet can be fermented using microorganisms such as yeast to produce bioethanol, which is then heated in the presence of a catalyst to obtain plant-derived ethylene and plant-derived α-olefins (1-butene, 1-hexene, etc.) through intramolecular dehydration reaction, etc. Next, using the obtained plant-derived ethylene and plant-derived α-olefins, and operating in the same manner as the manufacture of petroleum-derived polyethylene resin, it is possible to manufacture plant-derived polyethylene resin.

[0105] The production methods of plant-derived ethylene, plant-derived α-olefins, and plant-derived polyethylene resins are described in detail in, for example, JP-A-2011-506628. Examples of the plant-derived polyethylene resin used in the present invention include Green PE manufactured by Braskem SA.

[0106] The plant-derived polyethylene resin used in the present invention can be any of the above-mentioned polyethylenes, and its density is preferably in the range of 0.890 to 0.970 g / cm 3 The range is preferably 0.910 to 0.960 g / cm 3 range.

[0107] <Polypropylene resin>

[0108] In the present invention, the content of the polypropylene resin is preferably 2 to 90% by mass, more preferably 5 to 85% by mass, and even more preferably 10 to 80% by mass, relative to 100% by mass of the resin composition.

[0109] In the first embodiment, the preferred content ratio of the polypropylene resin is a content ratio relative to 100% by mass of the melt-blown nonwoven fabric. By including the polypropylene resin in addition to the polyethylene resin, productivity in the melt-blowing method is improved, and gelation due to a cross-linking reaction can be suppressed even at 250° C. or above, thereby obtaining a fine-fine nonwoven fabric.

[0110] In the second embodiment and the third embodiment, each suitable content ratio of the polypropylene resin is a content ratio relative to 100% by mass of each of the electret materials.

[0111] The polypropylene resin used in the present invention may be "derived from fossil raw materials", "derived from plants", or a mixture of the two, and a favorable composition can be selected from the viewpoints of availability and LCA.

[0112] In the present invention, "derived from fossil raw materials" means: a component obtained by thermal decomposition of naphtha as a main component, and the naphtha is obtained from fossil raw materials represented by petroleum, coal, natural gas, etc. "Derived from plants" means obtained from bio-propylene and bio-naphtha as polyethylene. The polypropylene resin used in the present invention is any polypropylene resin suitable for the resin composition of the present invention, preferably the melt-blown nonwoven fabric (first embodiment), and the electret material (second and third embodiments).

[0113] As the polypropylene used in the present invention, any of a homopolymer, a random copolymer, and a block copolymer can be used, and two or more thereof can be used in combination. For example, as the polypropylene derived from petroleum, any of a homopolymer, a random copolymer, and a block copolymer can be used, and two or more thereof can be used in combination.

[0114] The total amount of the polyethylene resin and the propylene resin is preferably 80% or more relative to 100% by mass of the total amount of the resin and the compatibilizer contained in the resin composition of the present invention.

[0115] When the total of the resin and the compatibilizer contained in the melt-blown nonwoven fabric (first embodiment) of the present invention is taken as 100% by mass, the total of the polyethylene resin and the polypropylene resin is preferably 80% by mass or more.

[0116] In the second embodiment and the third embodiment, the total amount of the polyethylene resin and the polypropylene resin is preferably 80% by mass or more relative to 100% by mass of each of the electret materials.

[0117] <Compatibilizer>

[0118] In the present invention, the content of the compatibilizer is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and even more preferably 2 to 10% by mass, relative to 100% by mass of the resin composition, that is, 100% by mass of the total of the polyethylene resin, the polypropylene resin and the compatibilizer.

[0119] In the first embodiment, each suitable content ratio of the compatibilizing agent is a ratio relative to 100% by mass of the melt-blown nonwoven fabric.

[0120] The suitable content ratios of the compatibilizer in the second embodiment and the third embodiment are content ratios relative to 100% by mass of the electret materials. In particular, in the third embodiment, when the content ratio of the compatibilizer is less than 0.1% by mass, the compatibilization effect may not be obtained and the productivity may be deteriorated, and when the content ratio of the compatibilizer is more than 20% by mass, the charge stability may be reduced.

[0121] The compatibilizer may be a compound that dissolves polyethylene resin and polypropylene resin, for example, polyethylene resin derived from plants and polypropylene resin derived from petroleum, in each other. Examples of such a compatibilizer include low-density polyethylene-g-polymethyl methacrylate, ethylene-glycidyl methacrylate copolymer-g-polymethyl methacrylate, ethylene-vinyl acrylate copolymer-g-polymethyl methacrylate, ethylene-vinyl acetate copolymer-g-polymethyl methacrylate, ethylene-propylene vinyl ester-maleic anhydride copolymer-g-polymethyl methacrylate. Graft copolymers of methyl ester of acid, ethylene vinyl alcohol, polystyrene-b-polyethylene butene-b-polyolefin crystals, terminal-modified polystyrene-b-polyethylene butene-b-polyolefin crystals, triblock copolymers of polyolefin crystals-b-polyethylene butene-b-polyolefin crystals, polycaprolactone (Japanese: ポリカプロラクタン), polypropylene / styrene elastomer compounds, maleic anhydride-modified polyethylene, etc. In addition, graft and block polymers having chain segments of the same polymer as the base polymer to be compatible, which is polyethylene and polypropylene in the present invention, can also be used.

[0122] Examples of commercially available compatibilizers include MODIPER (registered trademark) A1100, MODIPER A1401, MODIPER A3400, MODIPER A4100, MODIPER 4300, MODIPER 4400, MODIPER 5300, MODIPER 5400, MODIPER 6600, MODIPER CL130D, MODIPER CL430-G, MODIPER SV10B, MODIPER SV10A, MODIPER S101, MODIPER SV30B, MODIPER S501, and MODIPER MS10B (all manufactured by NOF Corporation), BONDFAST (registered trademark) 2C, BONDFAST E, BONDFAST 2B, BONDFAST 7B, BONDFAST 7L, BONDFAST 7M, and BONDFAST VC40 (all manufactured by Sumitomo Chemical Co., Ltd.), BONDINE (registered trademark) LX4110, BONDINE HX8210, BONDINE TX8030, BONDINE HX8290, BONDINE 5500, BONDINEAX8390 (all manufactured by Tokyo Material Co., Ltd.), REXPEARL (trademark) ET220X, REXPEARL ET230X, REXPEARL T530H, REXPEARL ET720X, REXPEARL EB050S, REXPEARL EB240H, REXPEARL EB330H, REXPEARL EB140F, REXPEARL EB230X, REXPEARL EB440H, REXPEARL A1100, REXPEARL A3100, REXPEARL A1150, REXPEARL A4200, REXPEARL A6200, REXPEARL A4250 (all products of Japan Polyethylene Co., Ltd.), Reseda (registered trademark) GS-1015, Reseda GP-310S, Reseda GP-301, ARUFON (registered trademark) UG-4010, ARUFON UG-4035, ARUFON UG-4040, ARUFON UG-4070, ARUFONUM-9001, ARUFON UM-9030, ARUFON UM-9040 (all products of Toagosei Co., Ltd.), EPOCROS (registered trademark), RPS-1005 (all products of Nippon Shokubai Co., Ltd.), DURANATE (registered trademark) 24A-100, DURANATE22A-75P, DURANATE TPA-100, DURANATE TKA-100, DURANATE P301-75E, DURANATE 21S-75E, DURANATE MHG-80B, DURANATE E402-80B, DURANATE E405-70B, DURANATE TSE-100, DURANATE AE700-100, DURANATE TSA-100, DURANATE TSS-100, DURANATE A201H, DURANATE TUL-100, DURANATE TLA-100, DURANATE D101, DURANATE D201, DURANATE A201H, DURANATE 50M-HDI, DURANATE MF-K60B, DURANATE SBB-70P, DURANATE SBN-70D, DURANATE MF-B60B, DURANATE 17B-60P, DURANATE TPA-B80E, DURANATE E402-B80B, DURANATE SBF-70E (Asahi Kasei Corporation), DYNARON (registered trademark) 6200P, DYNARON 6201B, DYNARON 8600P, DYNARON 8300P, DYNARON 8903P, DYNARON 9901P (JSR Corporation), L-MODU (trademark) S400, L-MODU S600, L-MODU S901 (Idemitsu Kosan Co., Ltd.), Vistamaxx (Vistamaxx (trademark)) 3000, Vistamaxx 3020FL, Vistamaxx 3588FL, Vistamaxx 3980FL, Vistamaxx 6000, Vistamaxx 6102, Vistamaxx 6102FL, Vistamaxx 6202, Vistamaxx 6202FL, Vistamaxx6502, 7020BF, Vistamaxx 8380, Vistamaxx 8780, Vistamaxx 8880 (the above is Exxon Mobil Co., Ltd.), FORTIFY (FORTIFY (trademark)) C0570, FORTIFY C0570D, FORTIFY C1055D, FORTIFYC1070, FORTIFY C1070D, FORTIFY C1085, FORTIFY C11075DF, FORTIFYC13060, FORTIFY C13060D, FORTIFY C30070D, FORTIFY C3080, FORTIFY C5070, FORTIFY C5070D (all from Saudi Basic Industries Corporation (SABIC)), etc.

[0123] The compatibilizer is not limited to the above-mentioned compatibilizers, and compatibilizers described in "Development, Evaluation, and Recycling of Plastic Compatibilizers" (published by CMC) and the like may be suitably used. The compatibilizer may be used alone or in combination of two or more.

[0124] Here, in the present invention, the compatibilizer is contained in the resin composition, preferably the meltblown nonwoven fabric (first embodiment), or the electret material (second and third embodiments), and may be present at the interface of either the polyethylene resin or the polypropylene resin, or at the interface of both.

[0125] <Other>

[0126] The melt flow rates (MFR) of the polypropylene resin and the polyethylene resin may be any. By adopting the configuration of the present invention, it is possible to obtain a melt-blown nonwoven fabric having excellent productivity and fine fineness.

[0127] Regarding the polyethylene resin used in the present invention, the value obtained by dividing the melt flow rate (MFR) of the polypropylene resin measured at a temperature of 230°C and a load of 2.16 kg in accordance with ASTM D 1238 by the melt flow rate (MFR) of the polyethylene resin measured at a temperature of 190°C and a load of 2.16 kg in accordance with ASTM D 1238 is preferably 0.1 to 200, more preferably 0.5 to 150, further preferably 1 to 100, and most preferably 1.5 to 50.

[0128] In the resin composition of the present invention, preferably the melt-blown nonwoven fabric (first embodiment), and the electret material (second and third embodiments), other polymers, colorants, stabilizers, nucleating agents, and other compounding agents may be added as needed within the scope of not impairing the purpose of the present invention. Here, as the optional compounding components, for example, various stabilizers such as conventionally known heat stabilizers and weather stabilizers, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, and the like can be cited.

[0129] <Nitrogen-containing compounds>

[0130] The resin composition of the present invention preferably contains a nitrogen-containing compound, and more preferably contains the nitrogen-containing compound in the following ratios relative to 100% by mass of the resin composition.

[0131] In the second embodiment and the third embodiment, the content of the nitrogen-containing compound is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, and further preferably 0.75 to 1.5% by mass relative to 100% by mass of each electret material. When the content of the nitrogen-containing compound is less than 0.1% by mass, the charge amount is reduced, so the filtration characteristics are reduced. When the content of the nitrogen-containing compound is more than 5% by mass, the stability as an electret may be lost due to the increase in hygroscopicity.

[0132] The nitrogen-containing compound is not particularly limited as long as it can obtain the above-mentioned desired properties, but is preferably a hindered amine compound containing at least one of a 2,2,6,6-tetramethylpiperidinyl structure and a triazine structure, and more preferably the hindered amine compound contains a 2,2,6,6-tetramethylpiperidinyl structure and a triazine structure.

[0133] The hindered amine compound is not particularly limited, and examples thereof include poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}] (CHIMASSORB (registered trademark) 944LD, manufactured by BASF Japan), dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl condensate (Tinuvin (registered trademark) 622LD, manufactured by BASF Japan), Japan Co., Ltd.), 2-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-2-butylpropanediol bis[1,2,2,6,6-pentamethyl-4-piperidyl] (Tinuvin (registered trademark) 144, manufactured by BASF Japan), polycondensate of dibutylamine 1,3,5-triazine·N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine·N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine (CHIMASSORB (registered trademark) 2020FDL, manufactured by BASF Japan), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)-phenol (Tinuvin (registered trademark) 1577FF, manufactured by BASF Japan), etc. Among them, those containing a 2,2,6,6-tetramethylpiperidine structure and a triazine structure are preferred, and CHIMASSORB (registered trademark) 944LD or CHIMASSORB (registered trademark) 2020FD is more preferred. As the hindered amine compound, one of the above compounds may be used alone, or two or more thereof may be used in combination.

[0134] <Metal salts of fatty acids>

[0135] The resin composition of the present invention preferably contains a nitrogen-containing compound and a fatty acid metal salt, and more preferably contains the fatty acid metal salt in the following ratios relative to 100% by mass of the resin composition.

[0136] In the third embodiment, the content of the fatty acid metal salt is preferably 0.01 to 1.0 mass %, more preferably 0.025 to 0.5 mass %, and even more preferably 0.05 to 0.1 mass % relative to 100 mass % of the electret material.

[0137] The fatty acid metal salt is not particularly limited, but is preferably a fatty acid metal salt having a straight-chain fatty acid group. In addition, the fatty acid group is preferably a fatty acid group having 10 to 20 carbon atoms. Specifically, aluminum laurate, aluminum myristate, aluminum palmitate, aluminum stearate, magnesium laurate, magnesium myristate, magnesium palmitate, magnesium stearate, etc. can be cited.

[0138] <Manufacturing method>

[0139] Hereinafter, the method for producing the resin composition of the present invention, the method for producing the meltblown nonwoven fabric of the first embodiment, and the method for producing the electret material of the second embodiment and the third embodiment will be described. The production method of the present invention is not limited to the following, and can be appropriately changed in consideration of the subject matter described before and after.

[0140] <Method for producing resin composition>

[0141] The resin composition of the present invention can be manufactured by melt-kneading a resin composition including a polyethylene resin at least partially containing a polyethylene resin derived from a plant, a polypropylene resin, a compatibilizer, and other compounding agents using an extruder or the like. The obtained resin composition can be further processed by various known methods. The resin composition of the present invention is preferably provided in the following first embodiment, and the desired melt-blown nonwoven fabric can be manufactured through the necessary manufacturing steps. In addition, the resin composition obtained by melt-kneading the resin composition containing a nitrogen-containing compound and a fatty acid metal is preferably provided in the manufacture of the following electret material, and the electret materials of the second and third embodiments can be manufactured.

[0142] <Method for producing meltblown nonwoven fabric>

[0143] The method for manufacturing a melt-blown nonwoven fabric as the first embodiment of the present invention can be carried out by the following melt-blowing method: a resin composition including a polyethylene resin at least partially containing a polyethylene resin derived from a plant, a polypropylene resin, a compatibilizer, and other compounding agents is melt-kneaded by an extruder or the like, the melt is ejected from a spinneret having a spinning nozzle, and is blown by a high-speed and high-temperature air flow ejected from the periphery of the spinneret, and is deposited in a predetermined thickness on a collecting belt in the form of self-adhesive microfibers to manufacture a web. At this time, an interlacing process may be continued as needed.

[0144] As a method for interweaving treatment, for example, the following methods can be appropriately used: a method of performing heat embossing treatment using an embossing roller; a method of performing welding (Japanese: melting) using ultrasonic waves; a method of interweaving fibers using a water jet; a method of performing welding using hot air; a method using needle punching, and the like.

[0145] From the viewpoint of uniformity of the nonwoven fabric, the average fiber diameter of the fibers constituting the meltblown nonwoven fabric of the present invention is preferably 10 μm or less, more preferably 8 μm or less, further preferably 5 μm or less, and most preferably 3 μm or less. The meltblowing method and the composition of the present invention can produce a fine nonwoven fabric that is difficult to achieve by other nonwoven fabric making methods.

[0146] The melt-blown nonwoven fabric of the present invention can be used in a wide range of applications, and can be particularly suitably used as a raw material for separation materials, sound absorbing materials, sanitary materials, living materials, and the like.

[0147] <Method for producing electret material>

[0148] Next, the method for producing the electret material according to the second embodiment and the third embodiment will be described.

[0149] In the electret material of the second embodiment, a polyethylene resin at least partially including a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, and a nitrogen-containing compound are melt-mixed.

[0150] The electret material of the third embodiment is the same as the second embodiment except that it further contains a fatty acid metal salt. That is, it is produced by melt-mixing a polyethylene resin at least partially containing a plant-derived polyethylene resin, a polypropylene resin, a compatibilizer, a nitrogen-containing compound, and a fatty acid metal salt.

[0151] The temperature of the molten resin in the above-mentioned melt mixing is preferably 200 °C or higher, more preferably 220 °C or higher, and most preferably 250 °C or higher. Other processes can be carried out by conventionally known methods. The obtained melt can be made into a sheet by a known method. As the sheet, for example, a meltblown nonwoven fabric or a spunbond nonwoven fabric manufactured by a known method can be exemplified. In addition, as a suitable example of the electret material, a meltblown nonwoven fabric can also be made by the same manufacturing method as in Embodiment 1.

[0152] <Shape of the electret material>

[0153] The electret material of the present invention can be used in all required shapes considered necessary, for example, as a sheet such as a fibrous material or a film; an extrusion molding material, a porous film, a powder, a surface coating of other materials, etc., using the function of the electret. Among them, for filter applications, a fibrous material is more preferred, and a meltblown nonwoven fabric or a spunbond nonwoven fabric is particularly preferred.

[0154] The above-mentioned fibrous material is preferably a fiber aggregate. As the fiber aggregate, for example, a woven fabric (Japanese: 織編物) formed of long fibers or short fibers, a nonwoven fabric, a cottony material, etc., a fibrous material obtained from a stretched film, etc. can be cited. A fiber aggregate refers to the following state: when the surface of the electret is observed using a scanning electron microscope, an optical microscope, or other devices, it is confirmed as a fibrous morphology, and at least a part of the fibers constituting the fiber aggregate is integrated by melting or interlacing between the fibers.

[0155] When the electret material of the present invention is a fibrous material (preferably a meltblown nonwoven fabric or a spunbond nonwoven fabric, the same hereinafter), the average fiber diameter of the fibers used in the fibrous material is preferably 0.001 to 100 μm, more preferably 0.05 to 50 μm, further preferably 0.1 to 30 μm, particularly preferably 0.3 to 25 μm, and most preferably 0.5 to 20 μm. When the average fiber diameter of the fibers is thicker than 100 μm, it is difficult to obtain practical trapping efficiency. In addition, in the third embodiment, the efficiency reduction during charge decay sometimes becomes larger. When the average fiber diameter of the fibers is thinner than 0.001 μm, it is difficult to produce an electret material with charges imparted. The above fineness is calculated as follows: Using a scanning electron microscope, 100 fiber diameters are measured in the same field of view without repetition of the fibers, and the geometric mean is calculated.

[0156] The electret method in the present invention is not particularly limited as long as the desired properties can be obtained when using the electret material. When the electret material of the present invention is a sheet-like material, such as a fibrous material (including melt-blown nonwoven fabrics and spunbonded nonwoven fabrics, the same below), a method of making the liquid contact or collide with the fibrous material (liquid contact charging method) is preferred. The liquid contact charging method can obtain an electret material with high filtering properties. More specifically, a method of making the liquid contact or collide with the fibrous material by suction, pressurization, ejection, etc. is preferred.

[0157] The liquid that contacts or collides in the liquid contact charging method is not particularly limited as long as the desired properties can be obtained. From the perspective of handling and performance, water is preferred. A liquid to which a secondary component (a component other than water) is added may be used instead of water. The conductivity and pH of the liquid can be adjusted by the type and amount of the secondary component added.

[0158] In the liquid contact charging method, the pH of the liquid that contacts or collides with the fibrous material is preferably 1 to 11, more preferably 3 to 9, and even more preferably 5 to 7. In addition, the conductivity of the liquid that contacts or collides with the fibrous material in the liquid contact charging method is preferably 100 μS / cm or less, more preferably 10 μS / cm or less, and even more preferably 3 μS / cm or less.

[0159] The filter and preferably the filter material using the electret material of the present invention are also included in the scope of the present invention. When the electret material of the present invention is used as a filter or a filter material, the QF value (filter material quality factor: QF [mmAq -1 ]=-[ln(1-(particle collection efficiency (%) / 100))] / [ventilation resistance (mmAq)]) is 1.0 mmAq -1 Above, preferably 1.1 mmAq -1 More preferably 1.2 mmAq -1 Above, more preferably 1.3 mmAq -1 Above, the most preferred is 1.4 mmAq -1 In particular, it is particularly preferred to use an electret filter produced by a melt-blown method with an average fiber diameter of 0.5 to 8 μm, preferably an average fiber diameter of 0.5 to 5 μm, to exceed the above QF value. -1 , the particles are not fully captured by the electret, and the performance as a filter becomes insufficient. The QF value in this specification is calculated based on the ventilation resistance when the air is ventilated along the thickness direction of the filter at a wind speed of 10 cm / s, and the number count value of the laser particle counter in the particle size zone of 0.3 to 0.5 μm.

[0160] In the third embodiment of the present invention, it is also a preferred embodiment that the performance maintenance rate of the filter medium obtained by the charge stability described in Experimental Example 3 described later is 0.75 or more.

[0161] The performance maintenance rate is the value obtained by dividing the filter quality factor (QF) value (AQF) after applying a heat load of 100°C to the sample by the filter quality factor (QF) value (BQF) before applying the heat load of 100°C (AQF / BQF).

[0162] When the electret material of the present invention is used as a filter or filter material, the particle collection efficiency at a wind speed of 10 cm / s can be adjusted in various ways according to the required characteristics, and is preferably 50% or more, more preferably 70% or more, further preferably 90% or more, and particularly preferably 95% or more. The particle collection efficiency in this specification is calculated based on the number count value of the particle size partition 0.3 to 0.5 μm of the laser particle counter before and after the filter when air is ventilated in the thickness direction of the filter at a wind speed of 10 cm / s.

[0163] When the electret material of the present invention is used as a filter or filter material, the air flow resistance at a wind speed of 10 cm / s is preferably in the range of 0.05 to 50 mmAq, more preferably 0.2 to 30 mmAq, and particularly preferably 0.5 to 20 mmAq. If the air flow resistance is too small, the performance as a filter becomes insufficient, and if the air flow resistance is too large, the advantages of the electret filter are lost.

[0164] The electret material and the electret filter and filter medium of the present invention can be used in combination with other components as needed. That is, the electret material of the present invention can be used in combination with a pre-filtration layer, a fiber protection layer, a reinforcing member, a functional fiber layer, etc.

[0165] As the pre-filtration layer and the fiber protection layer, for example, spunbonded nonwoven fabric, thermally bonded nonwoven fabric, foamed urethane, etc., as the reinforcing member, for example, thermally bonded nonwoven fabric, various nets, etc., can be exemplified. In addition, as the functional fiber layer, for example, a colored fiber layer for the purpose of antibacterial, antiviral, and identification, design, etc. can be exemplified.

[0166] The electret material of the present invention can be used in a wide range of applications, particularly for the purposes of protection, ventilation, antifouling, waterproofing, etc., and can be suitably used as dust covers, dustproof clothing, various air conditioning components, air purifiers, cabin filters, and filters for the purpose of protecting various devices.

[0167] This application claims the benefit of priority based on Japanese Patent Application No. 2022-138525, Japanese Patent Application No. 2022-138526, and Japanese Patent Application No. 2022-138527 filed on August 31, 2022. The entire contents of the specifications of Japanese Patent Application No. 2022-138525, Japanese Patent Application No. 2022-138526, and Japanese Patent Application No. 2022-138527 filed on August 31, 2022 are incorporated herein by reference.

[0168] Example

[0169] The present invention will be described in more detail below with reference to the following examples. However, the present invention is not limited to the following examples and can be implemented with appropriate modifications within the scope consistent with the above and the following gist. All of these are included in the technical scope of the present invention.

[0170] Experimental Example 1

[0171] Hereinafter, the first embodiment of the present invention will be described. The test method is as follows.

[0172] (1) Weight per unit area

[0173] Samples with a diameter of 72 mmΦ were collected at three points, and the weight of each sample was measured. The obtained values ​​were converted per unit area, and their arithmetic mean was rounded off to the first decimal place to obtain the result.

[0174] (2) Average fiber diameter

[0175] Five random locations of the sheet sample were selected, and the diameter of the single fiber was measured at each of n=20 locations using an electron microscope, and the average fiber diameter was calculated by arithmetic averaging.

[0176] (3) Productivity

[0177] Sheet samples of 10 cm in length and 30 cm in width were collected at three points, and the surface was visually observed to confirm the presence or absence of defects. The presence of one or more non-fibrous resin lumps was evaluated as productivity × (unacceptable), and the absence of such defects was evaluated as productivity 0 (good).

[0178] <Example 1-1>

[0179] As raw materials, 50% by mass of a plant-derived high-density polyethylene resin (biomass degree 90% or more) having a melt flow rate (MFR) of 20 g / 10 minutes (catalog value) and 47% by mass of a petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes (catalog value) were added with 3% by mass of DYNARON (registered trademark) 6200P of JSR Corporation as a compatibilizer, and melt-spun at a molten resin temperature (actual molten resin temperature) of 290° C. using a melt-blowing device to obtain a fiber having a weight per unit area of ​​38 g / m 2 Fiber sheet (meltblown non-woven fabric).

[0180] Here, the biomass degree is an index showing the extent to which plant-derived raw materials are used, and is obtained by measuring the amount of 14C.

[0181] <Example 1-2>

[0182] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P of JSR Corporation as a compatibilizer was added to 70% by mass of a plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes and 27% by mass of a petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes, and the same operation as in Example 1-1 was performed to obtain a product having a weight per unit area of ​​38 g / m 2 The fiber sheet (melt-blown nonwoven fabric) of Example 1-2.

[0183] <Comparative Example 1-1>

[0184] A fiber sheet of Comparative Example 1-1 was obtained in the same manner as in Example 1 except that only a plant-derived high-density polyethylene resin having an MFR of 20 g / 10 min was used as a raw material. However, there were many fusions between fibers, and a sheet could not be obtained.

[0185] <Comparative Example 1-2>

[0186] A fiber sheet of Comparative Example 1-2 was obtained in the same manner as in Example 1-1 except that 3% by mass of DYNARON (registered trademark) 6200P of JSR Corporation as a compatibilizer was added to 97% by mass of a plant-derived high-density polyethylene resin (biomass content 90% or more) having an MFR of 20 g / 10 minutes as a raw material. However, there were many fusions between the fibers, and a sheet could not be obtained.

[0187] <Comparative Examples 1-3>

[0188] As raw materials, 50% by mass of a plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes and 50% by mass of a petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes were used. The same operation as in Example 1-1 was performed to obtain a product with a unit weight of 38 g / m 2 The fiber sheets of Comparative Examples 1-3.

[0189] <Comparative Examples 1-4>

[0190] As raw materials, a plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes was used at 70% by mass and Mitsui Chemicals Hi-WAX 200P (polyethylene wax) was used at 30% by mass. The same method as in Example 1-1 was used to obtain a 38 g / m 2 The fiber sheets of Comparative Examples 1-4.

[0191] Table 1 shows the blending ratios and properties of Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-4.

[0192] [Table 1]

[0193]

[0194] As shown in Table 1, Examples 1-1 and 1-2 have excellent productivity and fine fineness compared to Comparative Examples 1-1 to 1-4. Comparative Examples 1-1 and 1-2 failed to obtain sheets (nonwoven fabrics). It is believed that Comparative Example 1-3 did not use a compatibilizer, resulting in a large number of resin balls, which adhered to the vicinity of the nozzle, and thus could not be fine-fine, resulting in sheet defects. It is believed that Comparative Example 1-4 used polyethylene wax, which increased the overall viscosity and could not be fine-fine.

[0195] Experimental Example 2

[0196] Next, a second embodiment of the present invention will be described. The test method is as follows.

[0197] (1) Ventilatory resistance

[0198] A sample punched out to 72mmφ was mounted on a connector with an effective ventilation diameter of 50mmφ. A micro differential pressure gauge with an inner diameter of 50mm was connected to the upper and lower pipes. Ventilation was conducted at a wind speed of 10cm / s along the thickness direction of the sample, and the differential pressure above and below the sample in the non-throttling state was measured as ventilation resistance (pressure loss).

[0199] (2) Particle collection efficiency and particle transmittance

[0200] A sample punched out to 72 mm φ was mounted on an adapter with an effective ventilation diameter of 50 mm φ, and air was ventilated at a wind speed of 10 cm / s in the thickness direction of the sample. The particle collection efficiency was measured by the following method using a light scattering particle counter KC-01E manufactured by RION.

[0201] Evaluation particles: atmospheric dust particles

[0202] Wind speed: 10cm / s

[0203] Particle collection efficiency [%] = (1-(particle number concentration of 0.3-0.5 μm particles after sample penetration / particle number concentration of 0.3-0.5 μm particles before sample penetration)) × 100

[0204] Particle transmittance = (number concentration of particles with a diameter of 0.3 to 0.5 μm after the sample passes through / number concentration of particles with a diameter of 0.3 to 0.5 μm before the sample passes through)

[0205] (3) Filter material quality factor (QF)

[0206] The QF value was calculated by the following formula using the ventilation resistance measured in (1) above and the particle collection efficiency measured in (2) above.

[0207] QF[mmAq -1 ]=-[ln(1-(particle collection efficiency (%) / 100))] / [ventilation resistance (mmAq)]

[0208] (4) Weight per unit area

[0209] The weight per unit area was determined under the same conditions as in Experimental Example 1.

[0210] (5) Average fiber diameter

[0211] Under the same conditions as in Experimental Example 1, the average fiber diameter was determined.

[0212] (6) Productivity

[0213] Under the same conditions as in Experimental Example 1, the productivity was evaluated.

[0214] <Example 2-1>

[0215] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P manufactured by JSR Corporation as a compatibilizer and 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF Corporation as a hindered amine compound as a nitrogen-containing compound were added to 50% by mass of a plant-derived high-density polyethylene resin (biomass degree 90% or more) having a melt flow rate (MFR) (catalog value) of 20 g / 10 minutes and 46% by mass of a petroleum-derived polypropylene resin having an MFR (catalog value) of 60 g / 10 minutes, and melt spinning was performed at a molten resin temperature (temperature of the resin actually melted) of 290° C. using a melt-blowing device to obtain a fiber having a weight per unit area of ​​38 g / m 2 The obtained fiber sheet was charged by passing water having an electrical conductivity of 0.7 μS / cm and a pH of 6.8 from the surface layer to the back layer, and then air-dried at 25° C. to obtain an electret sheet. The characteristics as a filter were evaluated by air permeability resistance and particle permeability.

[0216] <Example 2-2>

[0217] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P manufactured by JSR and 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF were added to 70% by mass of a plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 min and 26% by mass of a petroleum-derived polypropylene resin having an MFR of 60 g / 10 min. The electret sheet of Example 2 was obtained in the same manner as in Example 2-1, except that the above was used.

[0218] <Comparative Example 2-1>

[0219] As a raw material, the electret sheet of Comparative Example 2-1 was obtained in the same manner as in Example 2-1, except that 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF was added to 50% by mass of a plant-derived high-density polyethylene resin (biomass degree of 90% or more) with an MFR of 20 g / 10 min and 49% by mass of a petroleum-derived polypropylene resin with an MFR of 60 g / 10 min.

[0220] <Comparative Example 2-2>

[0221] As a raw material, the electret sheet of Comparative Example 2-2 was obtained in the same manner as in Example 2-1, except that 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF was added to 70% by mass of a plant-derived high-density polyethylene resin (biomass degree of 90% or more) with an MFR of 20 g / 10 minutes and 29% by mass of a petroleum-derived polypropylene resin with an MFR of 60 g / 10 minutes.

[0222] <Comparative Example 2-3>

[0223] As a raw material, a sheet of Comparative Example 2-3 was obtained in the same manner as in Example 2-1 except that 3% by mass of DYNARON (registered trademark) 6200P manufactured by JSR and 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF were added to 96% by mass of a plant-derived high-density polyethylene resin (biomass content 90% or more) having a melt flow rate (MFR) of 20 g / 10 minutes. However, there were many fusions between the fibers, and a sheet could not be obtained.

[0224] <Comparative Example 2-4>

[0225] An electret sheet of Comparative Example 2-4 was obtained in the same manner as in Example 2-1 except that 1 mass % of Chimassorb (registered trademark) 944 manufactured by BASF was added to 96 mass % of a petroleum-derived high-density polyethylene resin having an MFR of 40 g / 10 min as a raw material.

[0226] Table 2 shows the blending ratios and properties of Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-4.

[0227] [Table 2]

[0228]

[0229] As can be seen from Table 2, Examples 2-1 and 2-2 are superior in productivity to Comparative Examples 2-1 to 2-4 and have high particle collection efficiency, that is, excellent electret performance.

[0230] Experimental Example 3

[0231] Next, a third embodiment of the present invention will be described. The test method is as follows.

[0232] (1) Ventilatory resistance

[0233] The ventilation resistance was determined under the same conditions as those in Experimental Example 2.

[0234] (2) Particle collection efficiency and particle transmittance

[0235] Under the same conditions as those in Experimental Example 2, the particle collection efficiency and the particle transmittance were determined.

[0236] (3) Filter material quality factor (QF)

[0237] The filter quality factor (QF) was determined under the same conditions as in Experimental Example 2.

[0238] (4) Weight per unit area

[0239] The weight per unit area was determined under the same conditions as in Experimental Example 1.

[0240] (5) Average fiber diameter

[0241] Under the same conditions as in Experimental Example 1, the average fiber diameter was determined.

[0242] (6) Charge stability

[0243] The sample used in (2) was wrapped with aluminum foil and left to stand in a dryer set at 100°C for 30 minutes. Then, the particle transmittance was measured by the same method as in (2) and the QF value was obtained by the same method as in (3). The obtained QF value was divided by the QF value obtained in (3) to obtain the performance maintenance rate.

[0244] <Example 3-1>

[0245] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P (compatibilizer) of JSR Corporation, 1% by mass of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF Corporation, and 0.075% by mass of magnesium stearate (metal fatty acid salt) were added to 50% by mass of plant-derived high-density polyethylene resin (biomass degree 90% or more) having a melt flow rate (MFR) of 20 g / 10 minutes (catalog value) and 45.925% by mass of petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes (catalog value) as a raw material, and melt spinning was performed at a molten resin temperature (temperature of the resin actually melted) of 290° C. using a melt-blowing device to obtain a fiber having a weight per unit area of ​​38 g / m 2 The obtained fiber sheet was charged by passing water having an electrical conductivity of 0.7 μS / cm and a pH of 6.8 from the surface layer to the back layer, and then air-dried at 25° C. to obtain an electret sheet. The characteristics as a filter were evaluated by air flow resistance and particle permeability.

[0246] <Example 3-2>

[0247] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P (compatibilizer) of JSR Corporation, 1% by mass of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF Corporation, and 0.075% by mass of magnesium stearate (metal fatty acid salt) were added to 70% by mass of plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes and 25.925% by mass of petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes. The electret sheet of Example 3-2 was obtained in the same manner as in Example 3-1, except that the above-mentioned materials were used.

[0248] <Comparative Example 3-1>

[0249] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P manufactured by JSR and 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF were added to 50% by mass of plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes and 46% by mass of petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes, and an electret sheet of Comparative Example 3-1 was obtained in the same manner as in Example 3-1. In Comparative Example 3-1, no metal fatty acid salt was added.

[0250] <Comparative Example 3-2>

[0251] As raw materials, 3% by mass of DYNARON (registered trademark) 6200P (compatibilizer) manufactured by JSR and 1% by mass of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF were added to 70% by mass of plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes and 26% by mass of petroleum-derived polypropylene resin having an MFR of 60 g / 10 minutes, and an electret sheet of Comparative Example 3-2 was obtained in the same manner as in Example 3-1. In Comparative Example 3-2, no metal fatty acid salt was added.

[0252] <Comparative Example 3-3>

[0253] As a raw material, a material obtained by adding 1 mass % of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF and 0.075 mass % of magnesium stearate (metal fatty acid salt) to 98.925 mass % of plant-derived high-density polyethylene resin (biomass degree 90% or more) having an MFR of 20 g / 10 minutes was used. The same operation as in Example 3-1 was performed to obtain a sheet of Comparative Example 3-3, but there were many fusions between fibers and a sheet could not be obtained. In Comparative Example 3-3, no compatibilizer was added.

[0254] <Comparative Example 3-4>

[0255] As a raw material, an electret sheet of Comparative Example 3-4 was obtained in the same manner as in Example 3-1 except that 1% by mass of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF and 0.075% by mass of magnesium stearate (metal fatty acid salt) were added to 98.925% by mass of a petroleum-derived high-density polyethylene resin having an MFR of 40 g / 10 minutes. In Comparative Example 3-4, no compatibilizer was added.

[0256] <Comparative Example 3-5>

[0257] As a raw material, an electret sheet of Comparative Example 3-5 was obtained in the same manner as in Example 3-1 except that 1% by mass of Chimassorb (registered trademark) 944 (nitrogen-containing compound) manufactured by BASF was added to 99% by mass of a petroleum-derived high-density polyethylene resin having an MFR of 40 g / 10 minutes. In Comparative Example 3-5, neither a compatibilizing agent nor a metal fatty acid salt was added.

[0258] Table 3 shows the blending ratios and properties of Examples 3-1 and 3-2 and Comparative Examples 3-1 to 3-5.

[0259] [Table 3]

[0260]

[0261] As can be seen from Table 3, Examples 3-1 and 3-2 are superior to Comparative Examples 3-1 to 3-5 in charge stability and are electret filters with low environmental load.

[0262] Industrial Applicability

[0263] The melt-blown nonwoven fabric of the present invention can make a great contribution to industries suitable for use as raw materials for sanitary materials, living materials, etc., because the fibers constituting the melt-blown nonwoven fabric have a fine fiber diameter, good texture, and low environmental load. However, its application range is not limited to the contents described here.

[0264] In addition, the electret material as a suitable embodiment (second embodiment) of the present invention has excellent electret performance and low environmental load, and therefore, for example, can be suitably used as a filter for dustproof clothing, dustproof cover, air purifier, etc., and can make a great contribution to the industry. However, its application range is not limited to the contents described here.

[0265] In addition, as for the electret material which is another suitable embodiment of the present invention (the third embodiment), the product life can be extended due to its excellent charge stability. In addition, the environmental load is small. Therefore, for example, it can be suitable for use as a filter for dustproof clothing, dustproof cover, air purifier, etc., and can make a great contribution to the industry. However, its application range is not limited to the contents described here.

Claims

1. A resin composition, characterized in that The invention comprises a polyethylene resin, a polypropylene resin and a compatibilizer, wherein the polyethylene resin comprises a polyethylene resin derived from plants. The resin composition according to claim 1 , further comprising a nitrogen-containing compound. The resin composition according to claim 1 , further comprising a nitrogen-containing compound and a fatty acid metal salt.

4. The resin composition according to any one of claims 1 to 3, wherein The compatibilizer is contained in an amount of 0.1% by mass to 20% by mass based on 100% by mass of the resin composition.

5. The resin composition according to claim 2, wherein The nitrogen-containing compound is contained in an amount of 0.1% to 5% by mass based on 100% by mass of the resin composition.

6. The resin composition according to claim 3, wherein The resin composition contains 0.1% to 5% by mass of the nitrogen-containing compound and 0.01% to 1% by mass of the fatty acid metal salt, based on 100% by mass of the resin composition.

7. The resin composition according to any one of claims 1 to 3, wherein The polyethylene resin is contained in an amount of 10% by mass to 98% by mass based on 100% by mass of the resin composition.

8. The resin composition according to any one of claims 1 to 3, wherein The compatibilizer is present in at least one of the polyethylene resin and the polypropylene resin.

9. The resin composition according to claim 2 or 3, wherein The nitrogen-containing compound includes a hindered amine compound. 10 . A melt-blown nonwoven fabric using the resin composition according to claim 1 .

11. The meltblown nonwoven fabric according to claim 10, wherein: The average fiber diameter of the fibers constituting the nonwoven fabric is 8 μm or less. 12 . An electret material using the resin composition according to claim 2 or 3 .

13. The electret material according to claim 12, wherein: The electret material is a sheet-like object.

14. The electret material according to claim 13, characterized in that: The sheet is a meltblown nonwoven fabric or a spunbonded nonwoven fabric.

15. The electret material according to claim 14, which is charged by a liquid contact charging method. 16 . An electret filter using the electret material according to claim 14 .

17. An electret filter material using the electret filter according to claim 16, wherein a performance maintenance rate obtained by dividing a value obtained by the following filter material quality factor QF after a heat load of 100°C is applied to the filter material by a value obtained by the following filter material quality factor QF before a heat load of 100°C is applied to the filter material is 0.75 or more, QF[mmAq -1 ] = -[ln(1-(particle capture efficiency (%) / 100))] / [ventilation resistance (mmAq)].

18. A method for manufacturing an electret material, characterized in that: The invention comprises the step of melt-mixing a polyethylene resin at least partially containing a polyethylene resin derived from a plant, a polypropylene resin, a compatibilizer and a nitrogen-containing compound.

19. A method for manufacturing an electret material, characterized in that: The invention comprises the step of melt-mixing a polyethylene resin at least partially containing a polyethylene resin derived from a plant, a polypropylene resin, a compatibilizing agent, a nitrogen-containing compound and a fatty acid metal salt.

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