KR20200126369A - Laminated nonwoven - Google Patents

Abstract

The present invention provides a nonwoven fabric composed of fibers containing a polyolefin resin, which has both water resistance and flexibility, and has excellent processability. The present invention is a laminated nonwoven fabric formed by laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer, wherein the spunbond nonwoven fabric layer is composed of a composite fiber comprising a thermoplastic resin (A1) and a polyethylene resin (A2), the thermoplastic The resin (A1) is a polyolefin resin (A1a) or a polyester resin (A1b), and the melt blown nonwoven fabric layer is composed of fibers containing a polyolefin resin (B), and a composite of the spunbond nonwoven fabric layer described above It relates to a laminated nonwoven fabric wherein the average single fiber diameter of the fibers is 6.5 to 11.9 μm, and the complex viscosity of the spunbond nonwoven fabric layer measured under conditions of 230°C and 6.28 rad/sec is 100 Pa·sec or less.

Description

Laminated nonwoven

The present invention relates to a laminated nonwoven fabric of the present invention, a spunbond nonwoven fabric layer composed of composite fibers and a melt blown nonwoven fabric layer are laminated, excellent in water resistance and flexibility, and excellent moldability as a building material use. will be.

In recent years, nonwoven fabrics are used for various purposes, and growth is expected in the future. Nonwoven fabrics are used in a wide range of applications, such as industrial materials, civil engineering materials, building materials, household materials, agricultural materials, sanitary materials and medical materials.

As the use of nonwoven fabrics, the use of building materials is attracting attention. BACKGROUND ART In recent constructions such as wooden houses, a ventilation layer construction method in which a ventilation layer is provided between an outer wall material and a heat insulating material, and moisture intruding into the wall is released to the outside through the ventilation layer has been widely used. In this ventilation layer construction method, a spunbond nonwoven fabric is used as a moisture-permeable waterproof sheet, which has both water resistance to prevent intrusion of rainwater from the outside of the building and moisture permeability to discharge moisture generated in the wall to the outside.

Although the spunbond nonwoven fabric is characterized by excellent moisture permeability from its structure, there is a problem in that water resistance is inferior. Therefore, the spunbond nonwoven fabric is laminated and integrated with a film having excellent water resistance to form a moisture-permeable waterproof sheet, and is used as a house wrap material.

House wrap material is installed by fixing it to the base with a binding needle (also called a tucker needle or staple), and has excellent long-term durability and weather resistance under high-temperature and low-temperature conditions, and durability that can withstand long-term use (water resistant Degradability) and excellent formability during construction are required.

Conventionally, as a moisture-permeable waterproof sheet used for such a house wrap material, a polyester-based nonwoven fabric having a single fiber diameter of 3 to 28 micrometers and a weight per unit area of 5 to 50 g/m 2 is used to achieve a good balance of moisture permeability and water resistance. Thus, a house wrap material in which a film having a thickness of 7 to 60 micrometers, comprising a block copolymer polyester having a hard segment and a soft segment, is laminated on this nonwoven fabric has been proposed (refer to Patent Document 1).

Japanese Patent No. 3656837

However, since the conventional house wrap material is a laminate of a nonwoven fabric and a film, there is a problem that the sheet is hard and moldability is inferior. The hardness of the sheet originates from the film, and although it is an effective means to reduce the ratio of the film to be bonded, there is a limit to the reduction of the film ratio from the viewpoint of water resistance.

Therefore, the object of the present invention has been made in view of the above circumstances, and its neck is to provide a nonwoven fabric that has both water resistance and high flexibility even if there is no film that has been used in the past, and is also excellent in moldability such as heat adhesion. have.

The present inventors, as a result of repeated scrutiny in order to achieve the above object, resulted in a spunbond nonwoven fabric layer composed of fibers containing two or more other types of polyolefin resin, and a melt blown nonwoven fabric layer composed of fibers containing polyolefin resin. It has been found that by using the laminated nonwoven fabric formed by lamination, by appropriately controlling the fluidity of the fibers constituting each nonwoven fabric layer, it has high flexibility and can improve the mechanical properties of the laminated nonwoven fabric. It has also been found that this laminated nonwoven fabric makes it possible to provide the intended high level of water resistance, flexibility, and workability mainly with thermal adhesion.

The present invention has come to completion based on these findings, and according to the present invention, the following invention is provided.

The laminated nonwoven fabric of the present invention is a laminated nonwoven fabric formed by laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer, and the spunbond nonwoven fabric layer is composed of a composite fiber comprising a thermoplastic resin (A1) and a polyethylene resin (A2). , The thermoplastic resin (A1) is a polyolefin-based resin (A1a) or a polyester-based resin (A1b), the melt blown nonwoven fabric layer is composed of fibers containing polyolefin resin (B), and the spunbond nonwoven fabric layer The average single fiber diameter of the conjugated fibers is 6.5 to 11.9 µm, and the complex viscosity of the spunbond nonwoven fabric layer measured under the conditions of 230°C and 6.28 rad/sec is 100 Pa·sec or less.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the water pressure per weight per unit area is 15 mmH ₂ O/(g/m 2) or more.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the melt flow rate of the fiber containing the polyolefin resin (A1) is 155 to 850 g/10 minutes.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the content of the melt blown nonwoven fabric layer is 1% by mass or more and 15% by mass or less based on the mass of the laminated nonwoven fabric.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the surface roughness SMD of at least one side by the KES method is 1.0 to 2.6 µm.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the average friction coefficient MIU of at least one side by the KES method is 0.1 to 0.5.

According to a preferred aspect of the laminated nonwoven fabric of the present invention, the variation MMD of the average coefficient of friction by the KES method on at least one side is 0.008 or less.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, a fatty acid amide compound having 23 or more and 50 or less carbon atoms is contained in the polyolefin resin (A2).

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the amount of the fatty acid amide compound added is 0.01 to 5.0% by mass.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the fatty acid amide compound described above is ethylenebisstearic acid amide.

According to the present invention, a spunbond nonwoven fabric layer composed of a composite fiber comprising a polyethylene-based resin, a polyolefin-based or a polyester-based resin, and a melt blown nonwoven fabric layer composed of a fiber comprising a polyolefin-based resin are laminated. A laminated nonwoven fabric having excellent water resistance and flexibility, and excellent processability is obtained. From these characteristics, the laminated nonwoven fabric of the present invention can be particularly suitably used as a building material application such as a moisture-permeable waterproof sheet.

Since the laminated nonwoven fabric of the present invention is excellent in water resistance, when used as a moisture-permeable waterproof sheet, the weight per unit area can be reduced compared to the conventional laminated nonwoven fabric.

In addition, in addition to being able to reduce the weight of the film to be bonded for the purpose of water resistance, it can be used for applications requiring high water resistance, which is difficult to apply in the conventional laminated nonwoven fabric.

In addition, since it is excellent in flexibility, when used as a building material application, wrinkles are less likely to occur in the process of bonding, and moldability becomes good.

1 is a schematic cross-sectional view illustrating a cross section of a composite fiber constituting the nonwoven fabric of the present invention.
2 is a schematic cross-sectional view illustrating a cross section of another composite fiber constituting the nonwoven fabric of the present invention.
3 is a schematic cross-sectional view illustrating a cross section of another composite fiber constituting the nonwoven fabric of the present invention.

The laminated nonwoven fabric of the present invention is a laminated nonwoven fabric formed by laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer, and the spunbond nonwoven fabric layer is composed of a composite fiber comprising a thermoplastic resin (A1) and a polyethylene resin (A2). , The thermoplastic resin (A1) is a polyolefin-based resin (A1a) or a polyester-based resin (A1b), the melt blown nonwoven fabric layer is composed of fibers containing polyolefin resin (B), and the spunbond nonwoven fabric layer The average single fiber diameter of the conjugated fibers of is 6.5 to 11.9 µm, and the complex viscosity of the laminated nonwoven fabric measured under conditions of 230°C and 6.28 rad/sec is 100 Pa·sec or less. Hereinafter, this detail will be described in detail.

[Thermoplastic resin (A1), (A2), polyolefin resin (B)]

Among the laminated nonwoven fabrics of the present invention, a thermoplastic resin (A1) and a polyethylene resin (A2) are used as the composite fibers constituting the spunbond nonwoven fabric layer.

Among these, for the thermoplastic resin (A1), a polyolefin resin (A1a) or a polyester resin (A1b) is used.

As the polyolefin resin (A1a), a polyolefin containing an olefin having 2 to 10 carbon atoms is preferably used. Specifically, ethylene, propylene, 1-butene, 1-pentene, 1-hexane, 4-methyl-1-pentene, 1-octene, and copolymers of their monomers and other α-olefins, and the like may be mentioned. These may be one type alone, or two or more types may be used in combination. Among them, it is preferable to use a polypropylene resin from the viewpoint of having strong strength and excellent dimensional stability in the production of sanitary materials.

With respect to the polyolefin resin (A1a) used in the present invention, when a polypropylene resin is used, the proportion of the homopolymer of propylene is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably It is 80% by mass or more. By setting it as the said range, good spinnability can be maintained and intensity|strength can be improved.

In addition, for the polyester resin (A1b) described above, a polyester containing an acid component and an alcohol component is used. As the acid component, for example, aromatic carboxylic acids such as terephthalic acid, isophthalic acid and phthalic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanecarboxylic acid, etc. can be used. I can. Moreover, ethylene glycol, diethylene glycol, polyethylene glycol, etc. can be used as an alcohol component.

Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid and polybutylene succinate, and copolymers thereof. By doing so, the strength of the laminated nonwoven fabric can be further improved, and when used for a house wrap, the fixing strength by staples can be improved. Among them, it is preferable to use polyethylene terephthalate from the viewpoint of obtaining high mechanical properties.

On the other hand, examples of the polyethylene resin (A2) used in the present invention include a homopolymer of ethylene or a copolymer of ethylene and various α-olefins. Examples of the polyethylene resin (A2) include medium-density, high-density, and linear low-density polyethylene (hereinafter sometimes referred to as LLDPE), and the like, and LLDPE is preferably used from the viewpoint of excellent spinnability.

The polyethylene-based resin used in the present invention may be a mixture of two or more, and a branching component different from ethylene, for example, a polyethylene-based copolymer of α-olefins such as butene, hexene, 4-methylpentene, heptene and octene. It is also possible to use a resin composition containing a resin or a thermoplastic elastomer.

In the polyethylene-based resin used in the present invention, additives such as antioxidants, weather stabilizers, light stabilizers, antistatic agents, anti-fog agents, anti-blocking agents, lubricants, nucleating agents and pigments, which are commonly used, within the range not impairing the effects of the present invention. , Or other polymers may be added as needed.

In addition, when releasing the fibers described later, in order to prevent the occurrence of partial viscosity unevenness, to make the fineness of the fibers uniform, and to thin the fiber diameter as described later, the resin to be used is decomposed to It is also contemplated to adjust the MFR. However, it is preferable not to add a free radical agent such as a peroxide, especially a dialkyl peroxide, or the like. In the case of using this method, a viscosity non-uniformity occurs in part and fineness becomes non-uniform, making it difficult to sufficiently thin the fiber diameter, and in some cases, the spinnability is deteriorated due to the non-uniformity of viscosity or bubbles caused by the decomposed gas.

The melting point of the polyethylene-based resin used in the present invention is preferably 80 to 160°C, more preferably 100 to 140°C. By setting the melting point to preferably 80°C or higher, more preferably 100°C or higher, it becomes easy to obtain heat resistance that can withstand practical use. In addition, when the melting point is preferably 160°C or less, more preferably 140°C or less, it is easy to adhere firmly to the polypropylene resin, and it is easy to spin without thread breakage.

In addition, for the polyolefin resin (B) of the fibers constituting the melt blown nonwoven fabric layer, like the polyolefin resin (A1a) described above, a polyolefin containing an olefin having 2 to 10 carbon atoms is preferably used. Among them, it is preferable to use a polypropylene resin from the viewpoint of having strong strength and excellent dimensional stability in the production of sanitary materials.

The flow characteristics of the thermoplastic resin (A1) of the composite fibers constituting the spunbond nonwoven fabric layer according to the present invention, the polyolefin resin (A2), and the polyolefin resin (B) of the fibers constituting the melt blown nonwoven fabric layer A value measured by ASTM D1238 (A method) is adopted as the melt flow rate (which may be abbreviated as MFR).

In addition, according to the above standard, for example, polypropylene is stipulated to be measured at a load: 2.16 kg, temperature: 230°C, and polyethylene at a load: 2.16 kg, temperature: 190°C. In addition, in the present invention, the measurement conditions for polyester are measured at load: 2.16 kg and 280°C.

First, it is preferable that the MFR of the thermoplastic resin (A1) of the fiber constituting the spunbond nonwoven layer is 155 to 850 g/10 min. By setting the MFR to 155 to 850 g/10 minutes, more preferably 155 to 600 g/10 minutes, and even more preferably 155 to 400 g/10 minutes, the fineness behavior of fibers when spinning the spunbond nonwoven fabric layer Even if it is stretched at a high spinning speed in order to stabilize and increase productivity, stable spinning is possible. In addition, by stabilizing the fine-grained behavior, thread fluctuation is suppressed, and unevenness when collecting in a sheet form is less likely to occur. In addition, since it becomes possible to stably stretch at a high spinning speed, orientation crystallization of fibers can be promoted, and fibers having high mechanical strength can be obtained.

In addition, it is also considered to blend two or more types of resins having different MFRs at an arbitrary ratio to adjust the MFR of the thermoplastic resin. However, in this case, the MFR of the resin blended with respect to the main thermoplastic resin is preferably 10 to 1000 g/10 minutes, more preferably 20 to 800 g/10 minutes, and even more preferably 30 to 600 g/10 minutes. . By setting it as the above range, it is possible to prevent that a viscosity non-uniformity occurs partially in the blended thermoplastic resin, resulting in non-uniform fineness and deterioration of spinnability.

In addition, it is preferable that the melt flow rate (MFR) of the polyethylene resin (A2) used in the present invention is 50 to 200 g/10 minutes. The MFR is preferably 50 to 200 g/10 minutes, more preferably 60 to 180 g/10 minutes, and even more preferably 70 to 150 g/10 minutes, even if it is stretched at a high spinning rate to increase productivity, the viscosity Since is low, it is possible to easily follow the deformation, and stable radiation becomes possible. Further, by stretching at a high spinning speed, orientation crystallization of the fibers is promoted, and fibers having high mechanical strength can be obtained.

Further, it is also contemplated that two or more types of resins having different MFRs are blended at an arbitrary ratio to adjust the MFR of the polyethylene-based resin (A2). However, in this case, the MFR of the resin blended with the main polyethylene-based resin is preferably 10 to 1000 g/10 minutes, more preferably 10 to 800 g/10 minutes, further preferably 10 to 600 g/10 minutes. to be. By setting it as the above range, it is possible to prevent that a viscosity nonuniformity occurs partially in the blended polyethylene-based resin (A2), resulting in nonuniformity in fineness and deterioration in spinnability.

Further, it is preferable that the MFR of the polyolefin resin (B) of the fibers constituting the melt blown nonwoven fabric layer is 200 to 2500 g/10 min. By setting the MFR to preferably 200 to 2500 g/10 minutes, more preferably 400 to 2000 g/10 minutes, and even more preferably 600 to 1500 g/10 minutes, stable spinning becomes easier and more Fibers containing the polyolefin resin (B) at the µm level can be obtained.

In the laminated nonwoven fabric of the present invention, it is important that the complex viscosity of the spunbond nonwoven fabric layer measured under the conditions of 230°C and 6.28 rad/sec is 100 Pa·sec or less. By setting it as the said range, even if it stretches at a high spinning speed in order to raise productivity, since the viscosity is low, it can easily follow with respect to a deformation|transformation, and stable spinning becomes possible. Further, by stretching at a high spinning speed, orientation crystallization of the fibers is promoted, and fibers having high mechanical strength can be obtained. The complex viscosity of the spunbond nonwoven layer is when mixed with a plurality of types of resins having different complex viscosities and a type of polyolefin resin such as a polyethylene resin or a polypropylene resin. It can be adjusted by mass ratio.

The complex viscosity (Pa·sec) of the spunbond nonwoven fabric layer of the present invention is measured under the following conditions using a dynamic viscoelasticity measuring device according to “3.3 Complex Shear Viscosity” of JIS K 7244-10 (2005). It is assumed that a value that is obtained is adopted.

(1) Measurement jig: φ20mm parallel plate

(2) Gap of the parallel plate: 0.5 mm

(3) Measurement temperature: 230℃

(4) Deformation: 34.9%

(5) Frequency: 0.3 to 63 rad/sec

In the composite fiber comprising the thermoplastic resin (A1) and the polyethylene resin (A2) constituting the spunbond nonwoven fabric layer of the present invention, the mass ratio of the polyethylene resin (A2) is 100 It is a mass %, it is preferable that it is 20-50 mass %, and it is a preferable aspect that the mass ratio of the thermoplastic resin (A1) is 50-80 mass %. By setting the mass ratio of polyethylene to preferably 20 to 50 mass%, more preferably 25 to 40 mass%, it has sufficient adhesive strength and can be made into a flexible composite fiber. Further, by setting the mass ratio of the thermoplastic resin (A1) to preferably 50 to 80% by mass, more preferably 60 to 75% by mass, it is possible to obtain a composite fiber having strength that can be provided for practical use.

In the thermoplastic resin (A1), polyethylene-based resin (A2), and polyolefin-based resin (B) used in the present invention, antioxidants, weather stabilizers, light-resistant stabilizers, and electrification agents commonly used within the scope of not impairing the effects of the present invention. Additives such as an inhibitor, an anti-fog agent, an anti-blocking agent, a lubricant, a nucleating agent and a pigment, or other polymers may be added as necessary.

The melting point of the thermoplastic resin (A1) or the polyethylene resin (A2) used in the present invention is preferably 80 to 200°C, more preferably 100 to 180°C, and still more preferably 120 to 180°C. When the melting point is preferably 80°C or higher, more preferably 100°C or higher, and still more preferably 120°C or higher, it becomes easy to obtain heat resistance that can withstand practical use. In addition, when the melting point is preferably 200°C or less, more preferably 180°C or less, it becomes easy to cool the yarn discharged from the detent, suppresses fusion between fibers, and makes it easy to perform stable spinning.

The melting point of the polyolefin resin (B) used in the present invention is preferably 80 to 200°C, more preferably 100 to 180°C, and still more preferably 120 to 180°C. By setting the melting point to preferably 80°C or higher, more preferably 100°C or higher, and still more preferably 120°C or higher, it becomes easy to obtain heat resistance that can withstand practical use. Further, when the melting point is preferably 180°C or less, more preferably 150°C or less, it becomes easy to cool the yarn discharged from the detent, suppresses fusion between fibers, and makes it easy to perform stable spinning.

In the laminated nonwoven fabric of the present invention, in order to improve slipperiness and flexibility, it is a preferred embodiment that the above-described polyethylene resin (A2) constituting the spunbond nonwoven fabric contains a fatty acid amide compound having 23 or more and 50 or less carbon atoms.

By setting the carbon number of the fatty acid amide compound to preferably 23 or more, more preferably 30 or more, excessive exposure of the fatty acid amide compound to the fiber surface is suppressed, resulting in excellent spinnability and processing stability, and high productivity. Can be maintained. On the other hand, when the number of carbon atoms of the fatty acid amide compound is preferably 50 or less, more preferably 42 or less, the fatty acid amide compound is liable to migrate to the fiber surface, and slipperiness and flexibility can be imparted to the laminated nonwoven fabric.

Examples of the fatty acid amide compound having 23 or more and 50 or less carbon atoms used in the present invention include saturated fatty acid monoamide compounds, saturated fatty acid diamide compounds, unsaturated fatty acid monoamide compounds, and unsaturated fatty acid diamide compounds.

Specifically, examples of the fatty acid amide compound having 23 or more and 50 or less carbon atoms include tetradocoic acid amide, hexadocoic acid amide, octadocoic acid amide, nerbonic acid amide, tetracosaentafenoic acid amide, nisinic acid amide, ethylene bislauric acid Amide, methylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenehydroxystearic acid amide , Distearyladipic acid amide, distearyl sebacic acid amide, ethylene bisoleic acid amide, ethylene bis erucic acid amide, and hexamethylene bis oleic acid amide, and a plurality of these may be used in combination.

In the present invention, among these fatty acid amide compounds, ethylenebisstearic acid amide, which is a saturated fatty acid diamide compound, is particularly preferably used. Since ethylenebisstearic acid amide is excellent in thermal stability, melt spinning is possible, and high productivity can be maintained by the polyethylene-based resin (A2) containing this ethylenebisstearic acid amide. In addition, since the slidability between the fibers is improved, the fibers can be uniformly dispersed during collection, thereby contributing to the improvement of the smoothness of the nonwoven fabric. Therefore, in the case of nonwoven fabrication, the pore diameter of the nonwoven fabric can be reduced, and a laminated nonwoven fabric excellent in water resistance and flexibility can be obtained.

In the present invention, the amount of fatty acid amide compound added to the entire resin constituting the spunbond nonwoven fabric layer constituting the laminated nonwoven fabric (the sum of the thermoplastic resin (A1) and the polyethylene resin (A2)) is 0.01 to 5.0% by mass. It is desirable. The addition amount of the fatty acid amide compound is preferably 0.01 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, and still more preferably 0.1 to 1.0% by mass, thereby maintaining suitable slipperiness and flexibility while maintaining spinnability. Can be given.

[fiber]

It is important that the composite fibers comprising the thermoplastic resin (A1) and the polyethylene resin (A2) constituting the spunbond nonwoven fabric layer according to the present invention have an average single fiber diameter of 6.5 to 11.9 µm. By setting the average single fiber diameter to 6.5 µm or more, preferably 7.5 µm or more, and more preferably 8.4 µm or more, a decrease in spinnability can be prevented, and a nonwoven fabric layer having excellent quality can be stably formed. On the other hand, when the average single fiber diameter is 11.9 µm or less, preferably 11.2 µm or less, and more preferably 10.6 µm or less, the flexibility and uniformity are high, and the content ratio of the melt blown nonwoven fabric layer is reduced. Also, it can be made into a laminated nonwoven fabric excellent in water resistance that can withstand practical use.

In the present invention, it is assumed that the average single fiber diameter (µm) of the conjugate fibers constituting the spunbond nonwoven fabric layer described above is a value calculated by the following procedure.

(1) A composite fiber containing a thermoplastic resin (A1) and a polyethylene resin (A2) is melt-released, pulled and stretched by an ejector, and then a nonwoven fabric layer is collected on a net.

(2) Ten small piece samples (100 x 100 mm) are randomly collected.

(3) Take a 500 to 1000 times surface photograph with a microscope, and measure the width of 100 composite fibers, 10 from each sample.

(4) The average single fiber diameter (µm) is calculated from the average value of 100 measured values.

1 to 3 are schematic cross-sectional views illustrating a cross section of a composite fiber constituting the spunbond nonwoven fabric of the present invention.

1 and 2 are schematic cross-sectional views showing a cross section of a core sheath-type composite fiber. In FIG. 1, the centers of the core portion (a) and the sheath portion (b) are the same, and in FIG. 2, the centers of the core portion (a) and the sheath portion (b) are different.

Specifically, the core sheath-type composite fiber includes a core portion (a) and a sheath portion (b), and the core portion (a) is at least partially surrounded by a polymer different from the core portion (a) in the cross-section of the fiber. It refers to a portion arranged and extending in the longitudinal direction of the fiber. In addition, the sheath portion (b) refers to a portion arranged so as to surround at least a part of the core portion (a) in the cross section of the fiber and extend in the longitudinal direction of the fiber. In the eccentric core sheath type composite fiber, there are an exposed type in which the side surface of the core portion (a) is exposed and a non-exposed type in which the side surface of the core portion (a) is not exposed. In the present invention, non-exposed eccentric core sheath-type composite fibers are preferably used from the stability of spinning.

3 is a schematic cross-sectional view showing a cross section of a side-by-side type composite fiber. The side-by-side type composite fiber has a structure in which a first component (c) and a second component (d) are bonded. The bonding surface of these two components may be a straight line or a curved line, and it differs depending on the viscosity characteristics of the two components and the discharge amount ratio. The cross section of the conjugate fiber may be circular or may be a deformed cross section such as an ellipse.

On the other hand, the fibers comprising the polyolefin resin (B) constituting the melt blown nonwoven fabric according to the present invention preferably have an average single fiber diameter of 0.1 to 8.0 µm, more preferably in the range of 0.4 to 7.0 µm. .

In addition, in the present invention, the average single fiber diameter (µm) of the fibers comprising the polyolefin resin (B) constituting the melt blown nonwoven fabric layer is a value calculated by the following procedure.

(1) The polyolefin-based resin (B) is melt-released and fine-grained with hot air, and then a nonwoven fabric layer is collected on a net.

(2) Ten small piece samples (100 x 100 mm) are randomly collected.

(3) Take 500 to 2000 times of surface photographs with a microscope, and measure the width of 100 fibers, 10 from each sample.

(4) The average single fiber diameter (µm) is calculated from the average value of 100 measured values.

[Non-woven fabric layer]

The water resistance of the laminated nonwoven fabric of the present invention can be controlled by the respective characteristics of the spunbond nonwoven fabric layer and the melt blown nonwoven fabric layer constituting the laminated nonwoven fabric. The water resistance of the spunbond nonwoven fabric layer can be controlled by the average fiber diameter of the constituting fibers or the dispersibility of the surface fibers of the nonwoven fabric layer. The water resistance of the melt blown nonwoven fabric layer can be controlled by the average fiber diameter of the constituent fibers, the mass ratio in the laminated nonwoven fabric, and the degree of fusion between the fibers constituting the melt blown nonwoven fabric layer.

[Laminated nonwoven fabric]

It is important that the laminated nonwoven fabric of the present invention is formed by laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer. By constituting in this way, it is possible to impart water resistance equal to or higher than the level required as a nonwoven fabric for house wrap materials.

In the laminated nonwoven fabric of the present invention, it is preferable that the water pressure per weight per unit area is 15 mmH ₂ O/(g/m 2) or more. By setting the water resistance per weight per unit area to preferably 15 mmH ₂ O/(g/m 2) or more, more preferably 17 mmH ₂ O/(g/m 2) or more, while maintaining water resistance that can withstand practical use. In addition, the laminated nonwoven fabric having excellent flexibility can be obtained, and the weight per unit area of the laminated nonwoven fabric can be reduced. The upper limit of the water pressure resistance is not particularly limited, but the upper limit that can be achieved while maintaining the nonwoven fabric structure is only 30 mmH ₂ O/(g/m 2 ).

In addition, as for the water resistance per weight per unit area of the laminated nonwoven fabric of the present invention, according to JIS L1092 (2009) "7.1.1A method (low water pressure method)", a value measured by the following procedure shall be adopted.

(1) Five test pieces having a width of 150 mm x 150 mm are taken from the laminated nonwoven fabric at equal intervals in the width direction of the laminated nonwoven fabric.

(2) Set the test piece to the clamp of the measuring device (the part that touches the water of the test piece is the size of 100 cm2).

(3) Raise the water level with a water level device at a speed of 600㎜/min±30㎜/min, and measure the water level when water comes out from three places on the back side of the test piece in mm.

(4) The above measurement is carried out on five test pieces, and the average value is taken as the water pressure resistance.

In addition, in the present invention, regarding the smoothness and good feel of the laminated nonwoven fabric, the surface roughness SMD according to the KES method (Kawabata Evaluation System), the average friction coefficient MIU by the KES method, and the average friction by the KES method. The coefficient of variation is evaluated by MMD.

It is preferable that the laminated nonwoven fabric of the present invention has a surface roughness SMD of 1.0 to 2.6 µm by the KES method on at least one side. The surface roughness SMD by the KES method is preferably 1.0 µm or more, more preferably 1.3 µm or more, still more preferably 1.6 µm or more, and even more preferably 2.0 µm or more, whereby the fiber is excessive. It can be prevented from deteriorating the texture or impairing the flexibility due to its densification.

On the other hand, the surface roughness SMD by the KES method is preferably 2.6 µm or less, more preferably 2.5 µm or less, still more preferably 2.4 µm or less, and still more preferably 2.3 µm or less, This smooth and rough feeling is small, and it can be made into a laminated nonwoven fabric having an excellent touch. The surface roughness SMD by the KES method can be controlled by appropriately adjusting the average single fiber diameter, the MFR of the laminated nonwoven fabric, and the like.

In the present invention, for the surface roughness SMD by the KES method, a value measured as follows is adopted.

(1) From the laminated nonwoven fabric, three test pieces having a width of 200 mm × 200 mm were taken at equal intervals in the width direction of the laminated nonwoven fabric.

(2) Set the test piece on the sample stand.

(3) The surface of the test piece is scanned with a contactor for surface roughness measurement (material: φ0.5 mm piano wire, contact length: 5 mm) applied with a load of 10 gf, and the average deviation of the uneven shape of the surface is measured.

(4) The above measurement was performed in the longitudinal direction (the length direction of the nonwoven fabric) and the transverse direction (the width direction of the nonwoven fabric) of all test pieces, and the average deviation of a total of six points was averaged and rounded to the second decimal place, The surface roughness is called SMD (㎛).

It is preferable that the average friction coefficient MIU of at least one side of the laminated nonwoven fabric of the present invention by the KES method is 0.1 to 0.5. By setting the average coefficient of friction MIU to preferably 0.5 or less, more preferably 0.45 or less, and still more preferably 0.4 or less, the sliding properties of the nonwoven fabric surface can be improved, and a laminated nonwoven fabric having a better feel can be obtained. .

On the other hand, when the average friction coefficient MIU is preferably 0.1 or more, more preferably 0.15 or more, and even more preferably 0.2 or more, excessive addition of the lubricant deteriorates the spinnability, or the yarn is trapped in the net. It is possible to prevent the thread from slipping at the time and the texture deteriorating. The average coefficient of friction MIU by the KES method can be controlled by appropriately adjusting the average single fiber diameter and the MFR of the laminated nonwoven fabric, or by adding a lubricant to the polyethylene resin (A2) or the polyolefin resin (B).

It is preferable that the variation MMD of the average coefficient of friction by the KES method of at least one side of the laminated nonwoven fabric of the present invention is 0.008 or less. By setting the variation MMD of the average friction coefficient to preferably 0.008 or less, more preferably 0.0075 or less, and still more preferably 0.0070 or less, the roughness of the surface of the laminated nonwoven fabric can be further reduced.

The variation MMD of the average coefficient of friction by the KES method can be controlled by appropriately adjusting the average single fiber diameter or the MFR of the laminated nonwoven fabric, or by adding a lubricant to the polyethylene resin (A2) or polyolefin resin (B). .

In the present invention, the average friction coefficient MIU and the variation MMD of the average friction coefficient according to the KES method adopt values measured as follows.

(1) From the laminated nonwoven fabric, three test pieces having a width of 200 mm × 200 mm were taken at equal intervals in the width direction of the laminated nonwoven fabric.

(2) Set the test piece on the sample stand.

(3) The surface of the test piece is scanned with a contact friction element (material: φ0.5 mm piano wire (20 parallel), contact area: 1 cm2) applied with a load of 50 gf, and the average coefficient of friction is measured.

(4) The above measurement was performed in the longitudinal direction (the length direction of the nonwoven fabric) and the transverse direction (the width direction of the nonwoven fabric) of all test pieces, the average deviation of a total of six points was averaged, and the fourth decimal place was rounded, It is called the average coefficient of friction MIU. Further, the variation in the average coefficient of friction of the above six points was further averaged, and the fourth digit after the decimal point was rounded off, and it was referred to as the variation MMD of the average friction coefficient.

In addition, in the present invention, the flexibility of the laminated nonwoven fabric is evaluated by air permeability and sensory tests.

It is preferable that the air permeability per weight per unit area of the laminated nonwoven fabric of the present invention is 0.5 to 10 (cc/(cm 2 ·second))/(g/m 2 ). The amount of ventilation per weight per unit area is preferably 8 (cc/(cm 2 sec))/(g/m 2) or less, more preferably 6 (cc/(cm 2 sec))/(g/m 2) By setting it as the following, more preferably 4 (cc/(cm2·sec))/(g/m2) or less, it is possible to sufficiently satisfy the air permeability required in house wrap applications and the like.

On the other hand, the ventilation amount per weight per unit area is preferably 0.2 (cc/(cm 2 sec))/(g/m 2) or more, more preferably 0.4 (cc/(cm 2 sec))/(g/ M2) or more, and more preferably 0.6 (cc/(cm2·sec))/(g/m2) or more, it is possible to prevent the spunbond nonwoven fabric from becoming excessively densified and impairing its flexibility. The ventilation amount can be adjusted by weight per unit area, single fiber fineness, weight per unit area of the melt blown layer, and thermocompression conditions (compression rate, temperature, and line pressure).

In addition, in the present invention, the air permeation amount per unit area of the laminated nonwoven fabric is a value measured by the following procedure in accordance with the "6.8.1 Frazier Method" of JIS L1913 (2010).

(1) A test piece of 80 cm x 100 cm is cut out from the laminated nonwoven fabric.

(2) The pressure of a barometer is 125 Pa, and it is measured about 20 arbitrary points in a test piece.

(3) The average value of the 20 points is calculated by rounding to the second decimal place.

(4) The calculated ventilation amount (cc/(cm2·sec)) is multiplied by the weight per unit area (g/m2).

In the laminated nonwoven fabric of the present invention, the content of the melt blown nonwoven fabric layer is preferably 1% by mass or more and 15% by mass or less, and more preferably 2% by mass or more and 10% by mass or less based on the mass of the laminated nonwoven fabric. When the content of the melt blown nonwoven fabric layer is preferably 1% by mass or more, and more preferably 2% by mass or more, water resistance that can withstand practical use can be imparted. In addition, when the content of the melt blown nonwoven fabric layer is preferably 5% by mass or less, and more preferably 10% by mass or less, the unique hardness of the melt blown nonwoven fabric can be reduced.

In addition, when the content of the spunbond nonwoven fabric layer in the laminated nonwoven fabric is preferably more than 85% by mass and less than 99% by mass, a laminated nonwoven fabric having excellent flexibility and workability can be obtained.

In addition, in the present invention, the content ratio of the melt blown nonwoven fabric layer adopts a value measured by the following procedure.

(1) Take three test pieces of width 100mm×100mm at equal intervals in the width direction of the laminated nonwoven fabric.

(2) Only the uncompressed portion of the laminated nonwoven fabric is taken.

(3) Measure the mass of the collected test piece and the melt blown nonwoven fabric collected from the test piece, respectively.

(4) The content ratio of the melt blown nonwoven fabric in the laminated nonwoven fabric is calculated.

It is preferable that the weight per unit area of the laminated nonwoven fabric of the present invention is 10 to 100 g/m 2. By setting the weight per unit area to preferably 10 g/m 2 or more, more preferably 13 g/m 2 or more, and still more preferably 15 g/m 2 or more, a laminated nonwoven fabric having mechanical strength that can be provided for practical use can be obtained. have.

On the other hand, the weight per unit area is preferably 100 g/m 2 or less, more preferably 50 g/m 2 or less, and even more preferably 30 g/m 2 or less, so that when using it as a house wrap material, the operator can hold it in hand during construction. It becomes a suitable weight when doing so, and can be made into a laminated nonwoven fabric excellent in handling property during construction. In addition, when used for other purposes, a laminated nonwoven fabric having excellent handling properties can be obtained.

In addition, in the present invention, the weight per unit area of the laminated nonwoven fabric adopts a value measured by the following procedure in accordance with "6.2 mass per unit area" of JIS L1913 (2010).

(1) Take 3 pieces of 20cm×25cm test piece per 1m width of the sample.

(2) Measure each mass (g) in a standard state.

(3) The average value is expressed as the mass per 1 m 2 (g/m 2 ).

It is preferable that the thickness of the laminated nonwoven fabric of the present invention is 0.05 to 1.5 mm. When the thickness is preferably 0.05 to 1.5 mm, more preferably 0.08 to 1.0 mm, more preferably 0.10 to 0.8 mm, flexibility and adequate cushioning properties are provided, and when used as a house wrap material, the operator It has an appropriate weight when carrying it in the hand, and the rigidity of the nonwoven fabric is not too strong, so that it can be a laminated nonwoven fabric having excellent handling properties during construction.

In the present invention, the thickness (mm) of the laminated nonwoven fabric adopts a value measured by the following procedure according to "5.1" of JIS L1906 (2000).

(1) Using a pressurizer having a diameter of 10 mm, the thickness of 10 points per 1 m is measured in units of 0.01 mm at equal intervals in the width direction of the nonwoven fabric with a load of 10 kPa.

(2) The average value of the 10 points is rounded to the third decimal place.

It is preferable that the apparent density of the laminated nonwoven fabric of the present invention is 0.05 to 0.3 g/cm 3. By setting the apparent density to preferably 0.3 g/cm 3 or less, more preferably 0.25 g/cm 3 or less, and even more preferably 0.20 g/cm 3 or less, the fibers are tightly packed and the flexibility of the laminated nonwoven fabric is impaired. Can be prevented.

On the other hand, by making the apparent density preferably 0.05 g/cm 3 or more, more preferably 0.08 g/cm 3 or more, and still more preferably 0.10 g/cm 3 or more, the occurrence of fluff or delamination is suppressed, It can be made into a laminated nonwoven fabric with strength, flexibility and handling properties that can withstand practical use.

In the present invention, the apparent density (g/cm 3) is calculated based on the following equation from the weight and thickness per unit area before rounding, and the third decimal place is rounded off.

· Apparent density (g/cm 3) =[Weight per unit area (g/㎡)]/[Thickness (mm)]×10 ^-3 .

The stress at 5% elongation per weight per unit area of the laminated nonwoven fabric of the present invention (hereinafter, it may be described as 5% modulus per weight per unit area) is 0.06 to 0.33 (N/25 mm)/(g/m²) It is preferably 0.13 to 0.30 (N/25 mm)/(g/m 2 ), and even more preferably 0.20 to 0.27 (N/25 mm)/(g/m 2 ). By setting it as the said range, it can be set as the spunbond nonwoven fabric which is flexible and excellent in touch while maintaining the strength that can be provided for practical use.

In the present invention, the stress at 5% elongation per unit area weight of the laminated nonwoven fabric is a value measured by the following procedure in accordance with "6.3 Tensile Strength and Elongation (ISO Method)" of JIS L1913 (2010). It shall be adopted.

(1) Three specimens of 25 mm x 300 mm are taken per 1 m in width for each of the longitudinal direction (the length direction of the non-woven fabric) and the transverse direction (the width direction of the non-woven fabric) of the non-woven fabric.

(2) The test piece is set in a tensile tester with a gripping interval of 200 mm.

(3) A tensile test is performed at a tensile speed of 100 mm/min, and the stress (5% modulus) at the time of 5% elongation is measured.

(4) Calculate the average value of the 5% modulus in the longitudinal and transverse directions measured on each test piece, calculate the 5% modulus per unit area based on the following equation, and round off the third decimal place.

· 5% modulus per weight per unit area ((N/25mm)/(g/m2))=[average value of 5% modulus (N/25mm)]/weight per unit area (g/m2).

[Method of manufacturing laminated nonwoven fabric]

Next, a preferred embodiment of the method for producing the laminated nonwoven fabric of the present invention will be described in detail.

The laminated nonwoven fabric of the present invention is a laminated nonwoven fabric including a nonwoven fabric produced by a spunbond (S) method and a melt blow (M) method. The manufacturing method of the laminated nonwoven fabric of the present invention can be performed according to any method as long as it is a method capable of laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer. For example, a method of forming a melt blown nonwoven fabric layer by directly depositing fibers formed by the melt blown method on a nonwoven fabric layer obtained by the spunbonding method, and then fusing the spunbonded nonwoven fabric layer and the melt blown nonwoven fabric layer, spun A method of superimposing a bonded nonwoven fabric layer and a melt blown nonwoven fabric layer and fusing both nonwoven fabric layers by heating and pressing, and a method of bonding the spunbond nonwoven fabric layer and the melt blown nonwoven fabric layer with an adhesive such as a hot melt adhesive or a solvent-based adhesive. Etc. can be employed. From the viewpoint of productivity, a method of directly forming a melt blown nonwoven fabric layer on the spunbond nonwoven fabric layer is a preferred embodiment.

In addition, depending on the purpose, the spunbond nonwoven fabric layer (S) and the melt blown nonwoven fabric layer (M) may be laminated with SM, SMS, SMMS, SSMMS and SMSMS.

In the spunbond nonwoven fabric layer, first, the molten thermoplastic resin (polyolefin resin) is discharged as long fibers from a spinning spout, drawn by suction with compressed air by an ejector, and then the fibers are collected on a moving net to form a nonwoven fabric layer. .

As the shape of the spinneret and ejector, various shapes such as a circle or a rectangle can be adopted. Among them, the use of compressed air is relatively small, the energy cost is excellent, the fusion or abrasion between the threads is difficult to occur, and the opening of the threads is also easy, so that a combination of a rectangular detent and a rectangular ejector is preferably used.

In the present invention, for example, a thermoplastic resin (A1) and a polyethylene-based resin (A2) are melted and metered in separate extruders, respectively, and a composite spinneret is used to form a fiber cross-section, preferably as shown in FIG. The core sheath fiber is fed into a spinneret, a polypropylene resin is disposed in the core component, and a polyethylene resin is disposed in the sheath component as long fibers having a core sheath-shaped cross section.

The spinning temperature when melting and spinning the thermoplastic resin (A1) and the polyethylene resin (A2) is preferably 200 to 270°C, more preferably 210 to 260°C, and still more preferably 220 to 250°C. to be. By setting the spinning temperature within the above range, it is possible to obtain a stable molten state and excellent spinning stability.

The yarns of the released long fibers are then cooled. As a method of cooling the discharged thread, for example, a method of forcibly spraying cold air into the thread, a method of naturally cooling at the ambient temperature around the thread, and a method of adjusting the distance between the spinneret and the ejector, etc. Or, a method of combining these methods may be employed. Further, cooling conditions can be appropriately adjusted and adopted in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the ambient temperature, and the like.

Subsequently, the cooled and solidified thread is pulled and stretched by compressed air injected from the ejector. The spinning speed is preferably 3,000 to 6,500 m/min, more preferably 3,500 to 6,500 m/min, and still more preferably 4,000 to 6,500 m/min. By setting the spinning speed to 3,000 to 6,500 m/min, high productivity is obtained, and orientation crystallization of the fibers proceeds, and high strength long fibers can be obtained. Normally, if the spinning speed is increased, the spinning property deteriorates and the filaments cannot be stably produced, but as described above, by using a thermoplastic resin (A1) and a polyethylene resin (A2) having a specific range of MFR, the intended composite Fiber can be spun stably.

Subsequently, the obtained long fibers are collected on a moving net to form a nonwoven fabric layer. In the present invention, it is also a preferable aspect to temporarily bond the nonwoven fabric layer by contacting a hot flat roll from one side thereof on a net. By doing in this way, it is possible to prevent the texture from deteriorating due to curling or blowing off of the surface layer of the nonwoven fabric layer during transport of the net, thereby improving the transportability from collecting the thread until thermocompression bonding.

Subsequently, for the melt blown nonwoven fabric, a conventionally known method can be employed. First, the polyolefin-based resin (B) is melted in an extruder and supplied to the detent, and hot air is blown onto the thread extruded from the detent to make fine, and then a nonwoven fabric layer is formed on the collecting net. In the melt blown method, a complicated process is not required, and fine fibers of several µm can be easily obtained, and high water resistance properties can be easily achieved.

Subsequently, the obtained spunbond nonwoven fabric layer and the melt blown nonwoven fabric layer are laminated and thermally bonded to each other to obtain an intended laminated nonwoven fabric.

The method of thermally bonding the nonwoven fabric layer is not particularly limited, but for example, a heat embossed roll in which pieces (uneven portions) are applied to the upper and lower pair of roll surfaces, and a roll in which one roll surface is flat (smooth) is different. Thermally bonded by various rolls, such as a thermal emboss roll including a combination of rolls with engraving (corrugations) on the side of the roll, and a thermal calender roll including a combination of a pair of top and bottom flat (smooth) rolls. A method, such as ultrasonic bonding, in which heat welding is performed by ultrasonic vibration of the horn.

Among them, since it is excellent in productivity, provides strength in the partial heat bonding area, and can maintain the texture and touch of the nonwoven fabric in the non-adhesive area, each piece (corrugated area) is implemented on the upper and lower pair of roll surfaces. It is a preferable aspect to use a heat emboss roll including a combination of a rolled thermal emboss roll or a roll in which one roll surface is flat (smooth) and a roll in which engraving (corrugations) is applied to the other roll surface.

As the surface material of the heat embossing roll, in order to obtain a sufficient thermal compression effect and to prevent a piece of the embossed roll from transferring to the surface of the other, a metal roll and a metal roll are paired. It is a preferred embodiment.

It is preferable that the emboss bonding area ratio by such a heat emboss roll is 5 to 30%. When the bonding area is preferably 5% or more, more preferably 8% or more, and still more preferably 10% or more, strength that can be provided for practical use as a laminated nonwoven fabric can be obtained. On the other hand, when the bonding area is preferably 30% or less, more preferably 25% or less, and still more preferably 20% or less, it is possible to obtain a suitable flexibility particularly suitable for use in a building material application. Even when ultrasonic bonding is used, it is preferable that the bonding area ratio is in the same range.

The bonding area referred to herein means the ratio of the bonding portion to the entire laminated nonwoven fabric. Specifically, in the case of thermal bonding with a pair of uneven rolls, it means that the proportion of the convex portion of the upper roll and the convex portion of the lower roll overlapping the portion (adhesive portion) of the nonwoven fabric layer occupies the entire laminated nonwoven fabric. . In addition, in the case of thermal bonding by a roll having irregularities and a flat roll, it means that the convex portions of the roll having irregularities occupy the entire laminated nonwoven fabric of a portion (adhesive portion) in contact with the nonwoven fabric layer. In addition, in the case of ultrasonic bonding, it means the ratio of the portion (adhesive portion) to be thermally welded by ultrasonic processing to the entire laminated nonwoven fabric.

The shape of the adhesive portion by thermal embossing roll or ultrasonic bonding is not particularly limited, and for example, a circle, an oval, a square, a rectangle, a parallelogram, a rhombus, a regular hexagon, and a regular octagon can be used. In addition, it is preferable that the bonding portions are uniformly present at regular intervals in the longitudinal direction (transport direction) and the width direction of the laminated nonwoven fabric. By doing in this way, fluctuations in the strength of the laminated nonwoven fabric can be reduced.

It is a preferable aspect that the surface temperature of the heat embossing roll at the time of heat bonding is -50 to -15°C with respect to the melting point of the polyethylene-based resin (A2) being used. By setting the surface temperature of the heat roll to preferably -50°C or higher, and more preferably -45°C or higher with respect to the melting point of the polyethylene-based resin (A2), the strength that can be appropriately thermally bonded and provided for practical use is achieved. A laminated nonwoven fabric can be obtained. In addition, by setting the surface temperature of the heat embossing roll to preferably -15°C or less, and more preferably -20°C or less with respect to the melting point of the polyethylene-based resin (A2), excessive thermal adhesion is suppressed and laminated nonwoven fabric As a result, it is possible to obtain appropriate flexibility and processability suitable for use in construction materials applications.

It is preferable that the line pressure of the heat emboss roll at the time of heat bonding is 50 to 500 N/cm. By setting the linear pressure of the roll to preferably 50 N/cm or more, more preferably 100 N/cm or more, and even more preferably 150 N/cm or more, it is appropriately thermally bonded and laminated with strength that can be provided for practical use. You can get a non-woven fabric.

On the other hand, by setting the line pressure of the thermal emboss roll to preferably 500 N/cm or less, more preferably 400 N/cm or less, and even more preferably 300 N/cm or less, as a laminated nonwoven fabric, particularly in the use of building materials. Suitable flexibility and processability suitable for the use of can be obtained.

In addition, in the present invention, for the purpose of adjusting the thickness of the laminated nonwoven fabric, before and/or after the thermal bonding with the thermal emboss roll described above, thermal compression bonding is performed by a thermal calender roll including a pair of upper and lower flat rolls. You can do it. The upper and lower pair of flat rolls is a metal roll or an elastic roll that has no irregularities on the surface of the roll, and can be used as a pair of a metal roll and a metal roll, or a pair of a metal roll and an elastic roll.

Here, the elastic roll is a roll made of a material having elasticity compared to a metal roll. Examples of the elastic roll include so-called paper rolls such as paper, cotton and aramid paper, and resin rolls containing urethane resins, epoxy resins, silicone resins, polyester resins, hard rubbers, and mixtures thereof. Can be lifted.

Example

Next, based on Examples, the laminated nonwoven fabric of the present invention will be specifically described. In the measurement of each physical property, the thing that does not have a special description is the measurement based on the above-described method.

(1) MFR of resin (g/10 min):

With respect to the MFR of the thermoplastic resin (A1) and the polyolefin resin (B), the polypropylene resins (A1a) and (B) were measured under conditions of a load of 2.16 kg and a temperature of 230°C. In addition, MFR of the polyethylene resin (A2) was measured under the conditions of a load of 2.16 kg and a temperature of 190°C.

(2) MFR of the laminated fiber (g/10 min):

The MFR of the laminated nonwoven fabric was measured under conditions of a load of 2.16 kg and a temperature of 230°C.

(3) Complex viscosity (Pa·sec):

Using the dynamic viscoelasticity measuring device "RHEOSOL-G3000", the complex viscosity (Pa·sec) of the laminated nonwoven fabric at a 20 mm parallel plate, a gap of 0.5 mm, a temperature of 230°C, a strain of 34.9%, and a frequency of 0.3 to 63 rad/sec. Measured.

(4) Spinning speed (m/min):

From the above-described average single fiber diameter and the solid density of the polyolefin resin (A) or polyolefin resin (B) to be used, the mass per 10,000 m in length is taken as the average single fiber fineness (dtex), and the second decimal place is rounded off. And calculated. From the average single fiber fineness and the discharge amount of the resin discharged from the spinneret single hole set in each condition (hereinafter, abbreviated as the single hole discharge amount) (g/min), the spinning speed was calculated based on the following equation.

Spinning speed (m/min) = (10000×[Single hole discharge amount (g/min)])/[Average single fiber fineness (dtex)].

(5) Water pressure resistance of the laminated nonwoven fabric (mmH ₂ O):

A water pressure tester "Hydro Tester" (FX-3000-IV type) manufactured by Swiss-Tex Test Co., Ltd. was used.

(6) Air permeability per unit area of the laminated nonwoven fabric ((cc/㎠·sec)/(g/m²)):

Based on the above-described method, the amount of air permeation was measured. In addition, the calculated ventilation amount (cc/(㎠·sec)) is calculated from the weight per unit area (g/m²) calculated based on the method described above, and rounded to the second decimal place from the following equation, Calculated skills.

· Aeration amount per weight per unit area = Ventilation amount (cc/(㎠·sec))/Weight per unit area (g/㎡).

(7) Surface roughness SMD (µm) of the laminated nonwoven fabric by the KES method:

For the measurement, an automated surface tester "KES-FB4-AUTO-A" manufactured by Kato Tech was used. The surface roughness SMD was measured on both sides of the laminated nonwoven fabric, and the value of the smaller of these was described in Table 1.

(8) The average coefficient of friction MIU by the KES method of the laminated nonwoven fabric, and the variation MMD of the average coefficient of friction by the KES method of the laminated nonwoven fabric:

For the measurement, an automated surface tester "KES-FB4-AUTO-A" manufactured by Kato Tech was used. The average coefficient of friction MIU was measured on both sides of the laminated nonwoven fabric, and Table 1 shows the value of the smaller one.

(9) Flexibility (processability) of nonwoven fabric:

As a sensory evaluation of the touch of the nonwoven fabric, points were given for flexibility in accordance with the following criteria. This was done by 10 people, and the average was evaluated as the feel of the nonwoven fabric. The higher each score was, the better the flexibility was, and it was judged that the workability in various processing was good, and 4.0 or more was considered as a pass.

<Flexibility (processability)>

5 points: flexible (good workability)

4 points: between 5 and 3 points

3: Average

2 points: between 3 and 1 points

1 point: Hard (poor workability).

[Example 1]

(Spunbond nonwoven fabric layer (lower layer))

In the spunbond nonwoven fabric layer, as a thermoplastic resin (A1), a polypropylene resin containing a homopolymer having an MFR of 170 g/10 minutes and a melting point of 163° C., a polyethylene resin (A2), and a homopolymer having an MFR of 100 g/10 minutes. Polyethylene resin (LLDPE) containing a polymer was used. The above-described thermoplastic resin (A1) and polyethylene-based resin (A2) were melted in an extruder, respectively, and from a rectangular cage having a hole diameter of 0.30 mm and a hole depth of 2 mm, the spinning temperature was 235°C and the single hole discharge amount was 0.43 g. /Min, and the thermoplastic resin (A1) was disposed in the core component, and the polyethylene-based resin (A2) was released from the core sheath-shaped cross section disposed in the sheath component. After the discharged thread was cooled and solidified, it was pulled and stretched by compressed air having an ejector pressure of 0.50 MPa in a rectangular ejector, and collected on a moving net. As a result, a spunbond nonwoven fabric layer having a weight per unit area of 8.2 g/m 2 including long fibers of the core sheath type composite fiber was formed. The properties of the fibers constituting the formed spunbond nonwoven fabric layer were, the average single fiber diameter was 10.9 µm, and the spinning speed converted from this was 5,050 m/min. Regarding the spinnability, yarn breakage was not observed and was good in spinning for 1 hour.

(Melt blown nonwoven layer)

Next, for the melt blown nonwoven fabric layer, a polypropylene resin containing a homopolymer having an MFR of 1100 g/min and a melting point of 163°C was used as the polyolefin resin (B). This polyolefin-based resin (B) was melted in an extruder, and the spinning temperature was 260°C and the single hole discharge amount was discharged at 0.10 g/min from a hole having a pore diameter φ of 0.25 mm. Thereafter, air was sprayed onto the yarn under the conditions of an air temperature of 290°C and an air pressure of 0.10 MPa, and collected on the above spunbond nonwoven fabric layer to form a melt blown nonwoven fabric layer. At this time, the weight per unit area of the melt blown nonwoven fabric layer separately collected on the collecting net under the same conditions was 1.6 g/m 2, and the average fiber diameter was 1.5 μm.

(Spunbond nonwoven fabric layer (upper layer))

Further, on the melt blown nonwoven fabric layer, long fibers of the core sheath composite fiber were collected under the same conditions as those in which the lower spunbond nonwoven fabric layer was formed to form a spunbond nonwoven fabric layer. Thereby, a spunbond-melt blow-spunbond laminated fiber web having a total weight per unit area of 18 g/m 2 was obtained.

(Laminated nonwoven fabric)

Subsequently, the obtained laminated fibrous web was prepared by using an emboss roll having an adhesion area rate of 16% in which a piece of metal polka dots was formed on an upper roll, and a pair of upper and lower heat emboss rolls composed of a flat roll made of metal on the lower roll. , A line pressure of 300 N/cm and a thermal bonding temperature of 120° C. were thermally bonded to obtain a laminated nonwoven fabric having a weight per unit area of 18 g/m 2. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Example 2]

(Spunbond nonwoven layer (lower layer), (upper layer))

As the thermoplastic resin (A1), in the same manner as in Example 1, except that a polypropylene resin containing a homopolymer having an MFR of 300 g/10 min and a melting point of 163° C. was used. To form a spunbond nonwoven fabric layer containing. The characteristics of the long fibers constituting the formed spunbond nonwoven fabric layer were, the average short fiber diameter was 10.5 µm, and the spinning speed converted from this was 5,500 m/min. Regarding the spinnability, yarn breakage was not observed and was good in spinning for 1 hour.

(Melt blown nonwoven layer)

In the same manner as in Example 1, a melt blown nonwoven fabric layer was formed. The properties of the fibers constituting the obtained melt blown nonwoven fabric layer had an average fiber diameter of 1.5 µm.

(Laminated nonwoven fabric)

In the same manner as in Example 1, a laminated nonwoven fabric was obtained. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Example 3]

(Spunbond nonwoven layer (lower layer), (upper layer))

In the same manner as in Example 1, except that a polypropylene resin containing a homopolymer having an MFR of 800 g/10 min and a melting point of 163°C was used as the thermoplastic resin (A1), A spunbond nonwoven fabric layer was formed. The characteristics of the long fibers constituting the formed spunbond nonwoven fabric layer were, the average short fiber diameter was 9.8 µm, and the spinning speed converted from this was 6,300 m/min. Regarding the spinnability, yarn breakage was not observed and was good in spinning for 1 hour.

(Melt blown nonwoven layer)

A melt blown nonwoven fabric layer was formed in the same manner as in Example 2.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Example 4]

(Spunbond nonwoven layer (lower layer), (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in Example 1, except that the single hole discharge amount was 0.21 g/min. The properties of the fibers constituting the formed spunbond nonwoven fabric layer were, the average single fiber diameter was 7.4 µm, and the spinning speed converted from this was 5,700 m/min.

(Melt blown nonwoven layer)

In the same manner as in Example 1, a melt blown nonwoven fabric layer fiber web was obtained.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Example 5]

(Spunbond nonwoven layer (lower layer), (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in Example 4, except that the weight per unit area was 8.5 g/m 2.

(Melt blown fiber web)

A melt blown nonwoven fabric layer was obtained in the same manner as in Example 1, except that the air pressure was 0.20 MPa and the weight per unit area was 1.0 g/m 2. The properties of the fibers constituting the obtained melt blown nonwoven fabric layer were 1.0 µm in average fiber diameter.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Example 6]

(Spunbond nonwoven layer (lower layer), (upper layer))

Spun in the same manner as in Example 1 except that 1.0 mass% of ethylene bis stearic acid amide was added to the polyethylene-based resin (A2) so that the addition amount to the entire resin constituting the spunbond nonwoven layer was 0.3 mass%. A bonded nonwoven fabric layer was obtained.

(Melt blown nonwoven layer)

In the same manner as in Example 1, a melt blown nonwoven fabric layer was obtained.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

[Comparative Example 1]

(Spunbond nonwoven layer (lower layer), (upper layer))

As the thermoplastic resin (A1), a spunbond nonwoven fabric layer was prepared in the same manner as in Example 1, except that a homopolypropylene resin having an MFR of 60 g/10 min and a melting point of 163°C was used, and the ejector pressure was 0.15 MPa. Got it. The characteristics of the long fibers constituting the obtained core sheath-type nonwoven fabric layer were, the average short fiber diameter was 18.0 µm, and the spinning speed converted from this was 1,900 m/min. Regarding the spinnability, the yarn breakage was 11 times defective in one hour of spinning.

(Melt blown nonwoven layer)

A melt blown nonwoven fabric layer was obtained in the same manner as in Example 1.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. With respect to the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per weight per unit area, surface roughness SMD, average friction coefficient MIU, and variation MMD of the average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. Table 1 shows the results.

[Comparative Example 2]

(Spunbond nonwoven layer (lower layer), (upper layer))

As the polyethylene resin (A2), a spunbond nonwoven fabric layer was obtained in the same manner as in Example 1, except that a homopolyethylene resin having an MFR of 20 g/10 min was used and the ejector pressure was 0.15 MPa. The characteristics of the long fibers constituting the obtained core sheath-type nonwoven fabric layer were the average short fiber diameter 17.4 µm, and the spinning speed converted from this was 1,900 m/min. Regarding the radioactivity, the yarn breakage was defective in 9 times in 1 hour of spinning.

(Melt blown nonwoven layer)

In the same manner as in Example 1, a melt blown nonwoven fabric layer was obtained.

(Laminated nonwoven fabric)

A laminated nonwoven fabric was obtained in the same manner as in Example 1. For the obtained laminated nonwoven fabric, the thickness, apparent density, water resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient were measured, and the flexibility of the laminated nonwoven fabric was evaluated. . Table 1 shows the results.

In Examples 1 to 6, the surface roughness SMD by the KES method was 1.8 to 2.1 µm, and the water pressure per weight per unit area was 15 mmH ₂ O/(g/m 2) or more, which had excellent water resistance. In addition, the laminated nonwoven fabric of Example 6, in which ethylene bis stearic acid amide was added to the fibers constituting the spunbond nonwoven fabric layer, has a reduced average coefficient of friction, increased flexibility, excellent processability, It was suitable.

On the other hand, the laminated nonwoven fabrics of Comparative Examples 1 and 2 had a surface roughness SMD of 2.7 µm or more, poor water resistance, and low flexibility.

Although the present invention has been described in detail using a specific aspect, it is clear to those skilled in the art that various changes and modifications can be made without departing from the intention and scope of the present invention. In addition, this application is based on a Japanese patent application filed on February 28, 2018 (Japanese Patent Application No. 2018-034870) and a Japanese patent application filed on July 27, 2018 (Japanese Patent Application No. 2018-141051), the entirety of which is It is used by quotation.

Since the laminated nonwoven fabric of the present invention has high productivity, uniform texture, smooth surface, excellent texture and touch, and higher water resistance, it can be suitably used as a moisture-permeable waterproof sheet and as a building material.

In addition, the use of the laminated nonwoven fabric of the present invention is not limited to the above, for example, industrial materials such as filters, filter base materials, wire wrapping materials, wallpaper, roofing materials, sound insulation materials, heat insulation materials, building materials such as sound-absorbing materials, wrapping Household materials such as materials, pocket materials, sign materials, printing materials, grass sheets, drainage materials, ground reinforcement materials, sound insulation materials, sound-absorbing materials, etc. Can be used for vehicle materials, etc.

(a): core part
(b): sheath
(c): first component
(d): second component

Claims (10)

A laminated nonwoven fabric formed by laminating a spunbond nonwoven fabric layer and a melt blown nonwoven fabric layer, wherein the spunbond nonwoven fabric layer is composed of a composite fiber containing a thermoplastic resin (A1) and a polyethylene resin (A2), and the thermoplastic resin (A1) Is a polyolefin-based resin (A1a) or a polyester-based resin (A1b), the melt blown nonwoven fabric layer is composed of fibers containing polyolefin resin (B), and the average end of the composite fibers of the spunbond nonwoven fabric layer A laminated nonwoven fabric having a fiber diameter of 6.5 to 11.9 µm and a complex viscosity of the spunbond nonwoven fabric layer measured under conditions of 230°C and 6.28 rad/sec being 100 Pa·sec or less. The laminated nonwoven fabric according to claim 1, wherein the water resistance per weight per unit area is 15 mmH ₂ O/(g/m 2) or more. The laminated nonwoven fabric according to claim 1 or 2, wherein a melt flow rate of fibers comprising the thermoplastic resin (A1) constituting the spunbond laminated nonwoven fabric is 155 to 850 g/10 minutes. The laminated nonwoven fabric according to any one of claims 1 to 3, wherein the content of the melt blown nonwoven fabric layer is 1% by mass or more and 15% by mass or less based on the mass of the laminated nonwoven fabric. The laminated nonwoven fabric according to any one of claims 1 to 4, wherein the surface roughness SMD of at least one side by the KES method is 1.0 to 2.6 µm. The laminated nonwoven fabric according to any one of claims 1 to 5, wherein the average friction coefficient MIU of at least one side by the KES method is 0.1 to 0.5. The laminated nonwoven fabric according to any one of claims 1 to 6, wherein the variation MMD of the average coefficient of friction by the KES method on at least one side is 0.008 or less. The laminated nonwoven fabric according to any one of claims 1 to 7, wherein the polyethylene-based resin (A2) contains a fatty acid amide compound having 23 or more and 50 or less carbon atoms. The laminated nonwoven fabric according to claim 8, wherein the amount of the fatty acid amide compound added is 0.01 to 5.0% by mass. The laminated nonwoven fabric according to claim 8 or 9, wherein the fatty acid amide compound is ethylenebisstearic acid amide.

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