CN111771020A

CN111771020A - Laminated nonwoven fabric

Info

Publication number: CN111771020A
Application number: CN201980015423.1A
Authority: CN
Inventors: 西村�一; 阪上好; 中野洋平; 羽根亮一; 西村诚
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2018-02-28
Filing date: 2019-02-22
Publication date: 2020-10-13
Also published as: KR20200126369A; JP7173021B2; WO2019167853A1; JPWO2019167853A1; TW201941928A

Abstract

The invention provides a nonwoven fabric which is composed of fibers containing polyolefin resin, has water resistance and flexibility and has excellent processability. The present invention relates to a laminated nonwoven fabric comprising a spunbonded nonwoven fabric layer and a meltblown nonwoven fabric layer laminated together, wherein the spunbonded nonwoven fabric layer is composed of composite fibers comprising a thermoplastic resin (A1) and a polyethylene resin (A2), the thermoplastic resin (A1) is a polyolefin resin (A1a) or a polyester resin (A1B), the meltblown nonwoven fabric layer is composed of fibers comprising a polyolefin resin (B), the composite fibers of the spunbonded nonwoven fabric layer have an average filament diameter of 6.5 to 11.9 [ mu ] m, and the spunbonded nonwoven fabric layer has a complex viscosity of 100Pa sec or less as measured at 230 ℃ and 6.28 rad/sec.

Description

Laminated nonwoven fabric

Technical Field

The present invention relates to a laminated nonwoven fabric obtained by laminating a spunbond nonwoven fabric layer made of composite fibers and a meltblown nonwoven fabric layer, which is excellent in water resistance and flexibility and excellent in moldability for use as a building material.

Background

In recent years, nonwoven fabrics are used in various applications, and are expected to grow in the future. The nonwoven fabric is used in a wide range of applications such as industrial materials, civil engineering materials, construction materials, living materials, agricultural materials, sanitary materials, and medical materials.

As the use of nonwoven fabrics, the use of building materials is attracting attention. In recent years, in buildings such as wooden houses, a technology of providing a breathable layer between an outer wall material and a heat insulating material and releasing moisture penetrating into the wall body to the outside through the breathable layer has been widespread. In this breathable layer process, a spunbond nonwoven fabric is used as a house packaging material which is a moisture-permeable waterproof sheet having both waterproofness for preventing rainwater from penetrating from the outside of a building and moisture permeability for allowing moisture generated in a wall body to escape to the outside.

The spunbond nonwoven fabric has a characteristic of excellent moisture permeability in view of its structure, but has a problem of poor water resistance. Therefore, a spunbonded nonwoven fabric is laminated with a film having excellent water resistance to form a moisture-permeable waterproof sheet, which is used as a house packaging material.

House packaging materials are constructed by fixing them to a base with a staple (also referred to as a nail gun pin or a staple), and are required to have excellent long-term durability, weather resistance under high-temperature and low-temperature conditions, durability (hydrolysis resistance) capable of withstanding long-term use, and excellent moldability during construction.

In order to achieve a good balance between moisture permeability and water resistance, a moisture-permeable waterproof sheet for use in such house packaging materials has been proposed, which uses a single fiber having a diameter of 3 to 28 μm and a weight per unit area of 5 to 50g/m²And a film having a thickness of 7 to 60 μm, which is formed of a block copolyester having a hard segment and a soft segment, is laminated on the nonwoven fabric (see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3656837

Disclosure of Invention

Problems to be solved by the invention

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 has poor moldability. The sheet hardness is due to the film, and it is effective to reduce the ratio of the film to be bonded, but there is a limit to reduce the ratio of the film from the viewpoint of water resistance.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a nonwoven fabric having both water resistance and high flexibility without using a film conventionally used, and having excellent moldability such as heat adhesiveness.

Means for solving the problems

The inventors of the present application have made intensive studies to achieve the above object, and as a result, have obtained the following findings: the laminated nonwoven fabric is obtained by laminating a spunbond nonwoven fabric layer composed of fibers containing two or more different polyolefin resins and a meltblown nonwoven fabric layer composed of fibers containing a polyolefin resin, and the flowability of the fibers constituting each nonwoven fabric layer is appropriately controlled, whereby the laminated nonwoven fabric has high flexibility and the mechanical properties of the laminated nonwoven fabric can be improved. It has also been found that the laminated nonwoven fabric can be provided with a target high level of water resistance, flexibility, and processability such as thermal adhesiveness.

The present invention has been completed based on these findings, and the present invention provides the following inventions.

The laminated nonwoven fabric is a laminated nonwoven fabric obtained by laminating a spunbond nonwoven fabric layer and a meltblown nonwoven fabric layer, wherein the spunbond nonwoven fabric layer is composed of composite fibers containing a thermoplastic resin (A1) and a polyethylene resin (A2), the thermoplastic resin (A1) is a polyolefin resin (A1a) or a polyester resin (A1B), the meltblown nonwoven fabric layer is composed of fibers containing a polyolefin resin (B), the composite fibers of the spunbond nonwoven fabric layer have an average filament diameter of 6.5 to 11.9 [ mu ] m, and the complex viscosity of the spunbond nonwoven fabric layer measured at 230 ℃ and 6.28rad/sec is 100Pa sec or less.

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the water pressure resistance per unit weight is 15mmH₂O/(g/m²) The above.

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

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the content of the meltblown nonwoven fabric layer is 1 mass% or more and 15 mass% or less with respect to 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 surface of the laminated nonwoven fabric by the KES method is 1.0 to 2.6 μm.

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

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

According to a preferred embodiment of the laminated nonwoven fabric of the present invention, the polyolefin resin (a2) contains a fatty acid amide compound having 23 to 50 carbon atoms.

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 is ethylene bisstearamide.

Effects of the invention

According to the present invention, a laminated nonwoven fabric excellent in water resistance and flexibility and excellent in processability can be obtained, the laminated nonwoven fabric being obtained by laminating a spunbond nonwoven fabric layer composed of composite fibers containing a polyethylene resin and a polyolefin or polyester resin and a meltblown nonwoven fabric layer composed of fibers containing a polyolefin resin. Due to these characteristics, the laminated nonwoven fabric of the present invention can be suitably used for building materials such as moisture-permeable waterproof sheets.

The laminated nonwoven fabric of the present invention has excellent water resistance, and therefore, when used as a moisture-permeable waterproof sheet, can realize a lower unit area weight than a conventional laminated nonwoven fabric.

In addition, the present invention can be used for applications requiring high water resistance, in which conventional laminated nonwoven fabrics are difficult to apply, in addition to reducing the weight of a film to be bonded for the purpose of water resistance.

Further, since the flexibility is excellent, when the composition is used for building materials, wrinkles are not easily generated particularly in a bonding step, and the moldability is good.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a cross section of a conjugate fiber constituting a nonwoven fabric of the present invention.

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

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

Detailed Description

The laminated nonwoven fabric is a laminated nonwoven fabric obtained by laminating a spunbond nonwoven fabric layer and a meltblown nonwoven fabric layer, wherein the spunbond nonwoven fabric layer is composed of composite fibers containing a thermoplastic resin (A1) and a polyethylene resin (A2), the thermoplastic resin (A1) is a polyolefin resin (A1a) or a polyester resin (A1B), the meltblown nonwoven fabric layer is composed of fibers containing a polyolefin resin (B), the composite fibers of the spunbond nonwoven fabric layer have an average filament diameter of 6.5 to 11.9 [ mu ] m, and the complex viscosity of the laminated nonwoven fabric measured at 230 ℃ and 6.28rad/sec is 100Pa sec or less. The details thereof will be described below.

[ thermoplastic resins (A1), (A2) and polyolefin resins (B) ]

In the laminated nonwoven fabric of the present invention, the thermoplastic resin (a1) and the polyethylene resin (a2) are used as the composite fibers constituting the spunbond nonwoven fabric layer.

Among them, polyolefin resin (A1a) or polyester resin (A1b) was used as the thermoplastic resin (A1).

As the polyolefin resin (A1a), a polyolefin containing an olefin having 2 to 10 carbon atoms is preferably used. Specific examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexane, 4-methyl-1-pentene, 1-octene, and copolymers of these monomers with other α -olefins. These can be used alone in 1 kind, also can be combined with more than 2 kinds. Among them, a polypropylene resin is preferably used in view of high strength and excellent dimensional stability in the production of sanitary materials.

In the case of using a polypropylene-based resin as the polyolefin-based resin (A1a) used in the present invention, the proportion of the homopolymer of propylene is preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more. By setting the above range, the strength can be improved while maintaining good spinning properties.

In addition, in the polyester-based resin (A1b), a polyester containing an acid component and an alcohol component was used. Examples of the acid component include 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 cyclohexane carboxylic acid. In addition, as the alcohol component, ethylene glycol, diethylene glycol, polyethylene glycol, and the like can be used.

Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof. In this way, the strength of the laminated nonwoven fabric can be further increased, and the fixing strength by staples can be increased when the laminated nonwoven fabric is used for house packaging. Among them, polyethylene terephthalate is preferably used from the viewpoint of obtaining high mechanical properties.

On the other hand, examples of the polyethylene resin (a2) used in the present invention include homopolymers of ethylene and copolymers of ethylene and various α -olefins. Examples of the polyethylene resin (a2) include medium-density, high-density and linear low-density polyethylene (hereinafter, may be referred to as LLDPE), and LLDPE is preferably used in view of excellent spinnability.

The polyethylene resin used in the present invention may be a mixture of 2 or more species, or a polyethylene resin obtained by copolymerizing a branched component different from ethylene, for example, an α -olefin such as butene, hexene, 4-methylpentene, heptene, or octene, or a resin composition further containing a thermoplastic elastomer or the like may be used.

Additives such as an antioxidant, a weather resistant stabilizer, a light resistant stabilizer, an antistatic agent, a spin mist agent, an anti-blocking agent, a lubricant, a nucleating agent, and a pigment, which are generally used, or other polymers may be added to the polyethylene resin used in the present invention as necessary within a range not to impair the effects of the present invention.

In spinning fibers described later, in order to prevent local viscosity unevenness from occurring, the MFR may be adjusted by making the fineness of the fibers uniform and by making the fiber diameter finer as described later, by decomposing the resin used. However, for example, it is preferable not to add a radical agent such as a peroxide, particularly a dialkyl peroxide. In the case of this method, local viscosity unevenness and fineness unevenness occur, and it is difficult to sufficiently reduce the fiber diameter, and the spinnability may be deteriorated due to the viscosity unevenness and bubbles generated by the decomposed gas.

The melting point of the polyethylene resin used in the present invention is preferably 80 to 160 ℃, and more preferably 100 to 140 ℃. By setting the melting point to preferably 80 ℃ or higher, more preferably 100 ℃ or higher, practical heat resistance can be easily obtained. Further, by setting the melting point to preferably 160 ℃ or lower, more preferably 140 ℃ or lower, it becomes easy to strongly adhere to the polypropylene resin, and the yarn is easily spun without breaking.

As the polyolefin resin (B) constituting the fibers of the meltblown nonwoven fabric layer, a polyolefin containing an olefin having 2 to 10 carbon atoms is preferably used, similarly to the polyolefin resin (A1 a). Among them, a polypropylene resin is preferably used in view of high strength and excellent dimensional stability in the production of sanitary materials.

The melt flow rate (abbreviated as MFR in some cases) indicating the flow characteristics of the thermoplastic resin (a1) constituting the conjugate fibers of the spunbond nonwoven fabric layer, the polyolefin resin (a2), and the polyolefin resin (B) constituting the fibers of the meltblown nonwoven fabric layer according to the present invention is a value measured by ASTM D1238 (method a).

In addition, according to the above-mentioned standards, for example: the polypropylene was measured under a load of 2.16kg at a temperature of 230 ℃ and the polyethylene was measured under a load of 2.16kg at a temperature of 190 ℃. In the present invention, the measurement conditions for the polyester were set to a load of 2.16kg and a temperature of 280 ℃.

First, the MFR of the thermoplastic resin (A1) constituting the fibers of the spunbonded nonwoven fabric layer is preferably 155 to 850g/10 min. By setting the MFR to 155 to 850g/10 min, more preferably 155 to 600g/10 min, and still more preferably 155 to 400g/10 min, the thinning behavior of the fibers at the time of spinning the spunbond nonwoven fabric layer is stabilized, and even if the fiber is drawn at a high spinning speed for improving productivity, stable spinning can be achieved. Further, by stabilizing the thinning behavior, the yarn shaking is suppressed, and unevenness is less likely to occur when the yarn is collected into a sheet shape. Further, since the drawing can be stably performed at a high spinning speed, the fiber can be oriented and crystallized, and a fiber having high mechanical strength can be obtained.

It is also conceivable to mix two or more 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 to be mainly mixed with the thermoplastic resin is preferably 10 to 1000g/10 min, more preferably 20 to 800g/10 min, and still more preferably 30 to 600g/10 min. By setting the above range, local viscosity unevenness in the thermoplastic resin to be mixed can be prevented from occurring and the fineness can be prevented from becoming non-uniform or the spinnability can be prevented from deteriorating.

The polyethylene resin (A2) used in the present invention preferably has a Melt Flow Rate (MFR) of 50 to 200g/10 min. By setting the MFR to preferably 50 to 200g/10 min, more preferably 60 to 180g/10 min, and still more preferably 70 to 150g/10 min, even when drawing is performed at a high spinning speed in order to improve productivity, the viscosity is low, and therefore, the yarn can easily follow deformation, and stable spinning can be achieved. Further, by drawing at a high spinning speed, the fiber can be oriented and crystallized, and a fiber having high mechanical strength can be produced.

It is also conceivable to adjust the MFR of the polyethylene resin (a2) by mixing two or more resins having different MFRs at an arbitrary ratio. However, in this case, the MFR of the resin to be mainly mixed with the polyethylene resin is preferably 10 to 1000g/10 min, more preferably 10 to 800g/10 min, and still more preferably 10 to 600g/10 min. By setting the above range, local viscosity unevenness in the polyethylene resin (a2) to be mixed can be prevented from occurring, and the fineness can be prevented from becoming uneven or the spinnability can be prevented from deteriorating.

The polyolefin resin (B) constituting the fibers of the meltblown nonwoven fabric layer preferably has an MFR of 200 to 2500g/10 min. By setting the MFR to preferably 200 to 2500g/10 min, more preferably 400 to 2000g/10 min, and even more preferably 600 to 1500g/10 min, stable spinning is facilitated, and a fiber containing the polyolefin resin (B) at a level of several μm 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 at 230 ℃ and 6.28rad/sec is 100Pa · sec or less. By setting the above range, even if drawing is performed at a high spinning speed in order to improve productivity, the viscosity is low, and therefore, deformation can be easily followed, and stable spinning can be achieved. Further, by drawing at a high spinning speed, the fiber can be oriented and crystallized, and a fiber having high mechanical strength can be produced. The complex viscosity of the spunbond nonwoven fabric layer can be adjusted by the kind of polyolefin resin such as polyethylene resin or polypropylene resin, and the mass ratio when a plurality of resins having different complex viscosities are mixed.

The complex viscosity (Pa · sec) of the spunbond nonwoven fabric layer of the present invention is a value measured under the following conditions using a dynamic viscoelasticity measuring apparatus according to "3.3 complex shear viscosity" of JIS K7244-10 (2005).

(1) A measuring clamp:

parallel plates

(2) Gap of the above parallel plates: 0.5mm

(3) Measuring temperature: 230 deg.C

(4) Strain: 34.9 percent

(5) Frequency: 0.3 to 63rad/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, a preferred embodiment is: the weight percentage of the polyethylene resin (A2) is 20-50% by weight, and the weight percentage of the thermoplastic resin (A1) is 50-80% by weight, based on 100% by weight of the entire resin constituting the conjugate fiber. By setting the mass ratio of the polyethylene to preferably 20 to 50 mass%, more preferably 25 to 40 mass%, the composite fiber has sufficient adhesive strength and can be made soft. Further, by setting the mass ratio of the thermoplastic resin (a1) to preferably 50 to 80 mass%, more preferably 60 to 75 mass%, a composite fiber having a practical strength can be produced.

Additives such as an antioxidant, a weather resistant stabilizer, a light resistant stabilizer, an antistatic agent, a spin mist agent, an anti-blocking agent, a lubricant, a nucleating agent, and a pigment, or other polymers, which are generally used, may be added to the thermoplastic resin (a1), the polyethylene resin (a2), and the polyolefin resin (B) used in the present invention as needed within a range not to impair the effects of the present invention.

The melting point of the thermoplastic resin (A1) or the polyethylene resin (A2) used in the present invention is preferably 80 to 200 ℃, more preferably 100 to 180 ℃, and still more preferably 120 to 180 ℃. By setting the melting point to preferably 80 ℃ or higher, more preferably 100 ℃ or higher, and further preferably 120 ℃ or higher, practical heat resistance can be easily obtained. Further, by setting the melting point to preferably 200 ℃ or lower, more preferably 180 ℃ or lower, the yarn discharged from the spinneret is easily cooled, and the fusion of the fibers is suppressed, whereby stable spinning is easily performed.

The melting point of the polyolefin resin (B) used in the present invention is preferably 80 to 200 ℃, more preferably 100 to 180 ℃, and still more preferably 120 to 180 ℃. By setting the melting point to preferably 80 ℃ or higher, more preferably 100 ℃ or higher, and further preferably 120 ℃ or higher, practical heat resistance can be easily obtained. Further, by setting the melting point to preferably 180 ℃ or lower, more preferably 150 ℃ or lower, the yarn discharged from the spinneret is easily cooled, and the fusion of the fibers is suppressed, whereby stable spinning is easily performed.

In order to improve the slidability and flexibility of the laminated nonwoven fabric of the present invention, it is preferable that the polyethylene resin (a2) constituting the spunbonded nonwoven fabric contains a fatty acid amide compound having 23 to 50 carbon atoms.

By making the number of carbon atoms of the fatty acid amide compound be preferably 23 or more, more preferably 30 or more, excessive exposure of the fatty acid amide compound to the fiber surface can be suppressed, and excellent spinning properties and processing stability can be achieved, 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 easily transferred to the fiber surface, and the non-woven laminate fabric can be provided with slidability and flexibility.

Examples of the fatty acid amide compound having 23 to 50 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 to 50 carbon atoms include tetracosanoic acid amide, hexacosanoic acid amide, octacosanoic acid amide, eicosenoic acid amide, tetracosanoic acid amide, ethylene bis-lauric acid amide, methylene bis-lauric acid amide, ethylene bis-stearic acid amide, ethylene bis-hydroxystearic acid amide, ethylene bis-behenic acid amide, hexamethylene bis-stearic acid amide, hexamethylene bis-behenic acid amide, hexamethylene hydroxystearic acid amide, distearyl adipic acid amide, distearyl sebacic acid amide, ethylene bis-oleic 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, ethylene bisstearic acid amide which is a saturated fatty acid diamide compound is particularly preferably used. Since ethylene bis stearamide has excellent thermal stability, melt spinning can be performed, and high productivity can be maintained by using the polyethylene resin (a2) containing ethylene bis stearamide. Further, the slippage of the fibers is improved, and the fibers can be uniformly dispersed at the time of collection, which contributes to the improvement of the smoothness of the nonwoven fabric. Therefore, when a nonwoven fabric is produced, the pore diameter of the nonwoven fabric can be reduced, and a laminated nonwoven fabric having excellent water resistance and flexibility can be obtained.

In the present invention, the amount of the fatty acid amide compound added is preferably 0.01 to 5.0% by mass based on the whole resin (the total of the thermoplastic resin (a1) and the polyethylene resin (a 2)) constituting the spunbond nonwoven fabric layer (constituting the laminated nonwoven fabric). The amount of the fatty acid amide compound added is preferably 0.01 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, and even more preferably 0.1 to 1.0% by mass, whereby appropriate slidability and flexibility can be imparted while maintaining the spinning property.

[ fibers ]

It is important that the composite fiber comprising the thermoplastic resin (a1) and the polyethylene resin (a2) constituting the spunbonded nonwoven fabric layer according to the present invention has an average filament diameter of 6.5 to 11.9 μm. By setting the average filament diameter to 6.5 μm or more, preferably 7.5 μm or more, and more preferably 8.4 μm or more, it is possible to prevent a decrease in spinnability and stably form a nonwoven fabric layer having good quality. On the other hand, by setting the average filament diameter to 11.9 μm or less, preferably 11.2 μm or less, and more preferably 10.6 μm or less, a laminated nonwoven fabric having high flexibility and uniformity and excellent water resistance that can withstand practical use even when the content ratio of the meltblown nonwoven fabric layer is reduced can be obtained.

In the present invention, the average filament diameter (μm) of the composite fibers constituting the spunbond nonwoven fabric layer is calculated by the following procedure.

(1) A composite fiber comprising a thermoplastic resin (a1) and a polyethylene resin (a2) was melt-spun, drawn and stretched by a jet, and the nonwoven fabric layer was collected on a web.

(2) 10 small samples (100X 100mm) were taken randomly.

(3) A surface photograph was taken 500 to 1000 times with a microscope, and the width of each of 10 composite fibers and a total of 100 composite fibers was measured from each sample.

(4) The average single fiber diameter (. mu.m) was calculated from the average of the measured values of 100 fibers.

Fig. 1 to 3 are schematic cross-sectional views illustrating cross sections of composite fibers constituting the spunbonded nonwoven fabric of the present invention.

Fig. 1 and 2 are schematic cross-sectional views showing cross sections of core-sheath composite fibers. In fig. 1, the center of the core portion (a) is the same as that of the sheath portion (b), and in fig. 2, the center of the core portion (a) is different from that of the sheath portion (b).

Specifically, the core-sheath composite fiber includes a core portion (a) and a sheath portion (b), and the core portion (a) is a portion which is arranged so that at least a part thereof is surrounded by a polymer different from the core portion (a) in a cross section of the fiber and extends in the longitudinal direction of the fiber. The sheath portion (b) is a portion which is arranged so as to surround at least a part of the core portion (a) in the cross section of the fiber and extends in the longitudinal direction of the fiber. In the core-sheath composite fiber having an offset core, 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, a non-exposed core-sheath type composite fiber is preferably used in view of the stability of spinning.

Fig. 3 is a schematic cross-sectional view showing a cross section of the side-by-side type composite fiber. The side-by-side type conjugate fiber has a structure in which the 1 st component (c) and the 2 nd component (d) are bonded. The joint surface of the two components may be any of a straight line and a curved line, and differs depending on the viscosity characteristics and the discharge amount ratio of the two components. The cross section of the composite fiber can be a circular cross section or an oval cross section.

On the other hand, the average filament diameter of the fibers comprising the polyolefin resin (B) constituting the meltblown nonwoven fabric layer according to the present invention is preferably in the range of 0.1 to 8.0 μm, and more preferably in the range of 0.4 to 7.0 μm.

In the present invention, the average filament diameter (μm) of the fibers including the polyolefin resin (B) constituting the meltblown nonwoven fabric layer is calculated by the following procedure.

(1) The polyolefin resin (B) was melt-spun, and after the polyolefin resin (B) was thinned with hot air, the nonwoven fabric layer was collected on a net.

(2) 10 small samples (100X 100mm) were taken randomly.

(3) A surface photograph was taken 500 to 2000 times with a microscope, and the width of 10 fibers was measured for each sample, and the total of 100 fibers was measured.

[ non-woven fabrics layer ]

The water resistance of the laminated nonwoven fabric of the present invention can be controlled by utilizing the properties of the spunbond nonwoven fabric layer and the meltblown 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 constituent fibers and the dispersibility of the fibers on the surface of the nonwoven fabric layer. The water resistance of the meltblown nonwoven fabric layer can be controlled by the average fiber diameter of the constituent fibers, the mass ratio of the constituent fibers in the laminated nonwoven fabric, and the degree of fusion between the fibers constituting the meltblown nonwoven fabric layer.

[ laminated nonwoven Fabric ]

In the laminated nonwoven fabric of the present invention, it is important to laminate a spunbond nonwoven fabric layer and a meltblown nonwoven fabric layer. With such a configuration, water resistance of a level or more required as a nonwoven fabric for house wrap can be provided.

The laminated nonwoven fabric of the present invention preferably has a water pressure resistance of 15mmH per unit area weight₂O/(g/m²) The above. By making the water pressure resistance per unit area weight preferably 15mmH₂O/(g/m²) Above, more preferably 17mmH₂O/(g/m²) As described above, a laminated nonwoven fabric having excellent flexibility while maintaining practical water resistance can be obtained, and a low unit area weight of the laminated nonwoven fabric can be realized. The upper limit of the water pressure resistance is not particularly limited, but the upper limit of the water pressure resistance can be up to 30mmH while maintaining the structure of the nonwoven fabric₂O/(g/m²)。

The water pressure resistance per unit weight of the laminated nonwoven fabric of the present invention is measured according to JISL1092 (2009) "7.1.1A method (low water pressure method)" in the following procedure.

(1) 5 test pieces of 150mm × 150mm width were sampled from the laminated nonwoven fabric at equal intervals in the width direction of the laminated nonwoven fabric.

(2) The test piece was set in a jig of a measuring apparatus (the portion of the test piece contacting water was 100 cm)²Size of (d).

(3) The water level was raised at a rate of 600 mm/min. + -. 30mm/min by using a leveling device filled with water, and the water level at the time of discharging water from 3 on the back side of the test piece was measured in mm units.

(4) The above measurement was carried out using 5 test pieces, and the average value thereof was set as the water pressure resistance.

In the present invention, the smoothness of the surface and the degree of improvement in touch feeling of the laminated nonwoven fabric are evaluated by the surface roughness SMD by the KES method (Kawabata Evaluation System), the average friction coefficient MIU by the KES method, and the variation MMD of the average friction coefficient by the KES method.

The laminated nonwoven fabric of the present invention preferably has a surface roughness SMD of 1.0 to 2.6 μm on at least one surface thereof by a KES method. By making the surface roughness SMD by the KES method preferably 1.0 μm or more, more preferably 1.3 μm or more, further preferably 1.6 μm or more, further preferably 2.0 μm or more, it is possible to prevent deterioration of hand and deterioration of flexibility due to excessive densification of the fiber.

On the other hand, by setting the surface roughness SMD by the KES method to preferably 2.6 μm or less, more preferably 2.5 μm or less, further preferably 2.4 μm or less, further preferably 2.3 μm or less, it is possible to produce a laminated nonwoven fabric having a smooth surface, a small rough feeling, and an excellent tactile sensation to the skin. The surface roughness SMD based on 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, the surface roughness SMD based on the KES method uses a value measured in the following manner.

(1) 3 test pieces of 200mm × 200mm width were collected from the laminated nonwoven fabric at equal intervals in the width direction of the laminated nonwoven fabric.

(2) The test piece was set on a sample table.

(3) The contact for measuring surface roughness was measured by a contact head to which a load of 10gf was applied (raw material:

music wire, contact length: 5mm) of the surface of the test pieceThe average variation of the uneven shape of the surface was measured.

(4) The above measurements were performed in the longitudinal direction (longitudinal direction of nonwoven fabric) and the transverse direction (width direction of nonwoven fabric) of all the test pieces, and the average deviations at 6 points in total were averaged, and the second decimal place was rounded off to obtain the surface roughness SMD (μm).

The laminated nonwoven fabric of the present invention preferably has an average friction coefficient MIU of 0.1 to 0.5 on at least one surface thereof by a KES method. By setting the average friction coefficient MIU to be preferably 0.5 or less, more preferably 0.45 or less, and further preferably 0.4 or less, the slidability of the nonwoven fabric surface is improved, and a laminated nonwoven fabric having a more satisfactory texture can be produced.

On the other hand, by setting the average friction coefficient MIU to be preferably 0.1 or more, more preferably 0.15 or more, and further preferably 0.2 or more, it is possible to prevent deterioration of spinnability due to excessive addition of a lubricant or deterioration of texture due to slippage of a yarn when the yarn is collected on a web. The average friction coefficient MIU by the KES method can be controlled by appropriately adjusting the average single fiber diameter, the MFR of the laminated nonwoven fabric, or the like, or can be controlled by adding a lubricant to the polyethylene resin (a2) or the polyolefin resin (B).

The change MMD of the average friction coefficient by the KES method in at least one surface of the laminated nonwoven fabric of the present invention is preferably 0.008 or less. The variation MMD of the average friction coefficient is preferably 0.008 or less, more preferably 0.0075 or less, and further preferably 0.0070 or less, whereby the roughness of the surface of the laminated nonwoven fabric can be further reduced.

The variation MMD of the average friction coefficient 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, or can be controlled by adding a lubricant to the polyethylene resin (a2) and the polyolefin resin (B).

In the present invention, the average friction coefficient MIU and the variation MMD of the average friction coefficient based on the KES method are values measured in the following manner.

(2) The test piece was set on a sample table.

(3) With a contact friction head to which a load of 50gf was applied (raw material:

music wire (20 parallel wires), contact area: 1cm²) The surface of the test piece was rubbed to measure the average friction coefficient.

(4) The above measurements were performed in the longitudinal direction (longitudinal direction of nonwoven fabric) and the transverse direction (width direction of nonwoven fabric) of all the test pieces, and the average deviation of 6 points in total was averaged, and the fourth decimal place was rounded off to obtain the average friction coefficient MIU. Further, the above-mentioned variation in the average friction coefficient at 6 points in total was averaged, and the fourth decimal place was rounded to give the variation MMD in the average friction coefficient.

In the present invention, the flexibility of the laminated nonwoven fabric was evaluated by the air permeability and the sensory test.

The laminated nonwoven fabric of the present invention preferably has an air permeability per unit area weight of 0.5 to 10 (cc/(cm))²Second))/(g/m)²). The air permeability per unit area weight is preferably 8 (cc/(cm)²Second))/(g/m)²) The lower, more preferably 6 (cc/(cm))²Second))/(g/m)²) The content is preferably 4 (cc/(cm))²Second))/(g/m)²) As described below, the air permeability required for house packaging applications and the like can be sufficiently satisfied.

On the other hand, the air permeability per unit area weight is preferably set to 0.2 (cc/(cm)²Second))/(g/m)²) More preferably 0.4 (cc/(cm))²Second))/(g/m)²) More preferably 0.6 (cc/(cm))²Second))/(g/m)²) This can prevent the spunbond nonwoven fabric from being excessively densified and from deteriorating flexibility. The air permeability can be determined by the weight per unit area, the fineness of single fiber, the weight per unit area of the meltblown layer, and the conditions of thermocompression bonding (compression bonding ratio, temperature, and line pressure)And (6) adjusting.

In the present invention, the air permeability per unit area weight of the laminated nonwoven fabric is measured by the following procedure in accordance with "6.8.1 Frazir type (Frazir) method" of JIS L1913 (2010).

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

(2) The measurement was performed at any 20 points in the test piece under a pressure of 125Pa by a barometer.

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

(4) The calculated ventilation volume (cc/(cm)²Sec)) multiplied by the weight per unit area (g/m)²)。

The laminated nonwoven fabric of the present invention is in the following form: the content of the meltblown nonwoven fabric layer is preferably 1 mass% or more and 15 mass% or less, and more preferably 2 mass% or more and 10 mass% or less, based on the mass of the laminated nonwoven fabric. By making the content of the meltblown nonwoven fabric layer preferably 1 mass% or more, more preferably 2 mass% or more, practical water resistance can be provided. Further, by making the content of the meltblown nonwoven fabric layer preferably 5 mass% or less, more preferably 10 mass% or less, the specific hardness of the meltblown nonwoven fabric can be reduced.

Further, by making the content of the spunbond nonwoven layer in the laminated nonwoven fabric preferably more than 85 mass% and less than 99 mass%, a laminated nonwoven fabric excellent in flexibility and processability can be obtained.

In the present invention, the content ratio of the meltblown nonwoven fabric layer is a value measured by the following procedure.

(1) 3 test pieces 100mm × 100mm in width were sampled at equal intervals in the width direction of the laminated nonwoven fabric.

(2) Only the non-crimped portions of the laminated nonwoven fabric were collected.

(3) The quality of the collected test piece and the quality of the melt-blown nonwoven fabric collected from the test piece were measured.

(4) The content ratio of the meltblown nonwoven fabric in the laminated nonwoven fabric was calculated.

The weight per unit area of the laminated nonwoven fabric of the present invention is preferably 10 to 100g/m². By making the weight per unit area preferably 10g/m²Above, more preferably 13g/m²More preferably 15g/m or more²As described above, a laminated nonwoven fabric having a practical mechanical strength can be obtained.

On the other hand, the weight per unit area is preferably 100g/m²Below, more preferably 50g/m²The lower, more preferably 30g/m²As described below, when used as a house wrapping material, the laminated nonwoven fabric can be made to have a weight suitable for a worker to handle during construction, and to have excellent workability during construction. Further, when used for other applications, a laminated nonwoven fabric having excellent handleability can be obtained.

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

(1) 3 test pieces 20cm by 25cm were collected per 1m width of the specimen.

(2) The respective masses (g) in the standard state were weighed.

(3) At a rate of 1m²Mass (g/m) of²) The average value thereof is shown.

The thickness of the laminated nonwoven fabric of the present invention is preferably 0.05 to 1.5 mm. By making the thickness of the nonwoven fabric preferably 0.05 to 1.5mm, more preferably 0.08 to 1.0mm, and even more preferably 0.10 to 0.8mm, the nonwoven fabric has flexibility and appropriate cushioning properties, and when used as a house packaging material, the nonwoven fabric becomes a weight suitable for a worker to handle during construction, and the nonwoven fabric does not have too strong rigidity, and a laminated nonwoven fabric having excellent workability during construction can be produced.

In the present invention, the thickness (mm) of the laminated nonwoven fabric is a value measured by the following procedure in accordance with JIS L1906 (2000) '5.1'.

(1) The thickness of the nonwoven fabric was measured at 10 points per 1m at 0.01mm intervals in the width direction under a load of 10kPa using a 10 mm-diameter pressure head.

(2) The third position after the decimal point of the average value at 10 above is rounded.

The apparent density of the laminated nonwoven fabric is preferably 0.05 to 0.3g/cm³. By making the apparent density preferably 0.3g/cm³Less than, more preferably 0.25g/cm³The concentration is preferably 0.20g/cm or less³As described below, the fibers are densely packed, and the flexibility of the laminated nonwoven fabric can be prevented from being impaired.

On the other hand, the apparent density is preferably set to 0.05g/cm³Above, more preferably 0.08g/cm³Above, more preferably 0.10g/cm³As described above, the occurrence of fuzz and delamination is suppressed, and a laminated nonwoven fabric having practical strength, flexibility, and handleability can be obtained.

In the present invention, the apparent density (g/cm)³) The weight per unit area and the thickness before rounding described above were calculated based on the following formulas, and the third digit after the decimal point was rounded.

Apparent density (g/cm)³) Weight per unit area (g/m)²)]/[ thickness (mm)]×10^-3。

The laminated nonwoven fabric of the present invention preferably has a stress at 5% elongation per unit weight (hereinafter, sometimes referred to as a 5% modulus per unit weight) of 0.06 to 0.33(N/25 mm)/(g/m)²) More preferably 0.13 to 0.30(N/25 mm)/(g/m)²) More preferably 0.20 to 0.27(N/25 mm)/(g/m)²). By setting the above range, a spun-bonded nonwoven fabric having softness and excellent touch feeling can be obtained while maintaining strength that can be used practically.

In the present invention, the stress at 5% elongation of the weight per unit area of the laminated nonwoven fabric is measured by the following procedure in accordance with "6.3 tensile strength and elongation (ISO method)" of JIS L1913 (2010).

(1) 3 test pieces of 25mm × 300mm were taken per 1m width of the nonwoven fabric in each of the longitudinal direction (longitudinal direction of the nonwoven fabric) and the transverse direction (width direction of the nonwoven fabric).

(2) The test pieces were set in a tensile testing machine at a clamping interval of 200 mm.

(3) A tensile test was conducted at a tensile rate of 100 mm/min, and the stress at 5% elongation (5% modulus) was measured.

(4) The average value of the 5% modulus in the machine direction and the transverse direction measured from each test piece was obtained, the 5% modulus per unit area weight was calculated based on the following formula, and the third decimal place was rounded.

5% modulus per weight of area ((N/25 mm)/(g/m)²) Not [ < 5% modulus mean value (N/25mm) ]]Weight per unit area (g/m)²)。

[ method for producing laminated nonwoven Fabric ]

Next, preferred embodiments of the method for producing the laminated nonwoven fabric of the present invention will be specifically described.

The laminated nonwoven fabric of the present invention is a laminated nonwoven fabric including nonwoven fabrics produced by a spunbond (S) method and a meltblown (M) method. The method for producing the laminated nonwoven fabric of the present invention may be carried out by any method as long as the spunbond nonwoven fabric layer and the meltblown nonwoven fabric layer can be laminated. For example, it is possible to employ: a method in which a spunbond nonwoven fabric layer and a meltblown nonwoven fabric layer are fused together after fibers formed by a meltblowing method are directly deposited on the nonwoven fabric layer obtained by a spunbonding method to form a meltblown nonwoven fabric layer; a method of superposing a spunbonded nonwoven fabric layer and a meltblown nonwoven fabric layer and fusing the two nonwoven fabric layers by heating and pressurizing; a method of bonding a spunbond nonwoven fabric layer and a meltblown nonwoven fabric layer with an adhesive such as a hot melt adhesive or a solvent-based adhesive; and so on. From the viewpoint of productivity, a preferred embodiment is a method of forming a meltblown nonwoven fabric layer directly on a spunbond nonwoven fabric layer.

In addition, the spunbonded nonwoven fabric layer (S) and the meltblown nonwoven fabric layer (M) may be laminated to form a structure of SM, SMs, SMMS, SSMMS, and SMSMS according to the purpose.

In the case of a spunbond nonwoven fabric layer, first, a molten thermoplastic resin (polyolefin resin) is spun as long fibers from a spinneret, and the spun filaments are drawn and stretched by compressed air through an ejector, and then the fibers are collected on a moving web to produce a nonwoven fabric layer.

The spinneret and the ejector may have various shapes such as a circular shape and a rectangular shape. Among them, a combination of a rectangular spinneret and a rectangular ejector is preferably used in view of a small amount of compressed air, excellent energy cost, less possibility of fusion or friction between yarns, and easy opening of yarns.

In the present invention, for example, the thermoplastic resin (a1) and the polyethylene resin (a2) are melted and metered in separate extruders, and are supplied to a composite spinneret, preferably a core-sheath spinneret forming a fiber cross section as shown in fig. 1, and spun as a long fiber having a core-sheath cross section in which the polypropylene resin is arranged as a core component and the polyethylene resin is arranged as a sheath component.

The spinning temperature when the thermoplastic resin (A1) and the polyethylene resin (A2) are melted and spun is preferably 200 to 270 ℃, more preferably 210 to 260 ℃, and still more preferably 220 to 250 ℃. By setting the spinning temperature within the above range, a stable molten state is obtained, and excellent spinning stability can be obtained.

The spun sliver of long fibers is then cooled. Examples of methods for cooling the spun sliver include: a method of forcibly blowing cold air to a sliver; a method of natural cooling by using the ambient temperature around the sliver; and a method of adjusting the distance between the spinneret and the ejector; etc., or a combination of these methods can be employed. The cooling conditions may be appropriately adjusted and used in consideration of the discharge amount per one hole of the spinneret, the spinning temperature, the atmospheric temperature, and the like.

Then, the cooled and solidified sliver is drawn and stretched by compressed air injected from an injector. 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, the oriented crystallization of the fiber can be performed with high productivity, and a long fiber with high strength can be obtained. In general, when the spinning speed is increased, the spinnability is deteriorated and the yarn-like fiber cannot be stably produced, but by using the thermoplastic resin (a1) and the polyethylene resin (a2) having the MFR within the specific range as described above, a desired composite fiber can be stably spun.

Then, the long fibers obtained were collected on a moving web to prepare a nonwoven fabric layer. In the present invention, it is also preferable that the nonwoven fabric layer is temporarily bonded to the web by contacting the roll from one side thereof. This prevents the surface layer of the nonwoven fabric layer from being turned over or blown during the web conveyance, thereby preventing deterioration of the texture and improving the conveyance performance from the yarn collection to the thermocompression bonding.

Next, the meltblown nonwoven fabric can be formed by a conventionally known method. First, the polyolefin resin (B) is melted in an extruder and supplied to a spinneret, and the strands extruded from the spinneret are blown with hot air to be thinned, and then a nonwoven fabric layer is formed on a collecting web. In the melt blowing method, fine fibers of several μm can be easily obtained without requiring a complicated process, and high water resistance can be easily achieved.

Next, the obtained spunbond nonwoven fabric layer and meltblown nonwoven fabric layer are laminated and thermally bonded to each other, thereby obtaining a desired laminated nonwoven fabric.

The method for thermally bonding the nonwoven fabric layer is not particularly limited, and examples thereof include: a method of performing thermal bonding by various rollers such as a hot embossing roller having engraved (uneven) portions on the upper and lower pair of roller surfaces, a hot embossing roller having a combination of a roller having a flat (smooth) one roller surface and a roller having engraved (uneven) portions on the other roller surface, and a hot calender roller having a combination of a pair of upper and lower flat (smooth) rollers; ultrasonic bonding in which the heat is thermally welded by ultrasonic vibration of a horn (horn).

Among them, from the viewpoint of excellent productivity, the ability to impart strength to a part of the thermally-bonded part, and the maintenance of the texture and the touch of the nonwoven fabric at the non-bonded part, it is preferable to use a heat embossing roll in which engraving (uneven portions) is performed on the upper and lower pair of roll surfaces, or a heat embossing roll formed by a combination of a roll having a flat (smooth) roll surface and a roll having engraving (uneven portions) performed on the other roll surface.

As a surface material of the heat embossing roll, in order to obtain a sufficient thermocompression bonding effect and prevent the engraved portions (uneven portions) of one embossing roll from being transferred to the surface of the other embossing roll, it is preferable to pair a metal roll and a metal roll.

The embossing bonding area ratio obtained by the hot embossing roller is preferably 5 to 30%. By setting the bonding area to 5% or more, more preferably 8% or more, and still more preferably 10% or more, it is possible to obtain strength that can be practically used as a laminated nonwoven fabric. On the other hand, by setting the bonding area to be preferably 30% or less, more preferably 25% or less, and further preferably 20% or less, appropriate flexibility suitable for use particularly in building material applications can be obtained. In the case of using ultrasonic bonding, the bonding area ratio is preferably in the same range.

The bonding area referred to herein means a ratio of the bonded portion to the whole laminated nonwoven fabric. Specifically, the thermal bonding by a pair of rollers having concave and convex portions means a ratio of a portion (bonded portion) where the convex portion of the upper roller overlaps with the convex portion of the lower roller and contacts the nonwoven fabric layer to the whole laminated nonwoven fabric. In the case of thermal bonding by the uneven roller and the troweling roller, the ratio of the portion (bonding portion) where the uneven roller and the nonwoven fabric layer are in contact with each other is the ratio of the whole laminated nonwoven fabric. In the case of ultrasonic bonding, the ratio of the portion thermally welded by ultrasonic processing (bonded portion) to the whole laminated nonwoven fabric is referred to.

The shape of the bonded portion obtained by the heat embossing roll or the ultrasonic bonding is not particularly limited, and for example, a circle, an ellipse, a square, a rectangle, a parallelogram, a rhombus, a regular hexagon, a regular octagon, or the like can be used. The bonding portions are preferably uniformly present at regular intervals in the longitudinal direction (conveying direction) and the width direction of the laminated nonwoven fabric. This can reduce variation in strength of the laminated nonwoven fabric.

The surface temperature of the hot embossing roll at the time of thermal bonding is preferably from-50 to-15 ℃ relative to the melting point of the polyethylene resin (A2) used. By setting the surface temperature of the heat roll to preferably-50 ℃ or higher, more preferably-45 ℃ or higher, relative to the melting point of the polyethylene resin (a2), it is possible to obtain a laminated nonwoven fabric having a practical strength by appropriately thermally bonding the heat roll. Further, by setting the surface temperature of the heat embossing roll to preferably-15 ℃ or lower, more preferably-20 ℃ or lower, with respect to the melting point of the polyethylene resin (a2), excessive thermal bonding can be suppressed, and appropriate flexibility and processability suitable for use in building material applications can be obtained as the laminated nonwoven fabric.

The linear pressure of the hot embossing roller during thermal bonding is preferably 50 to 500N/cm. By setting the linear pressure of the roller to preferably 50N/cm or more, more preferably 100N/cm or more, and further preferably 150N/cm or more, it is possible to obtain a laminated nonwoven fabric having a practical strength by appropriately thermally bonding the rollers.

On the other hand, by setting the linear pressure of the heat embossing roll to preferably 500N/cm or less, more preferably 400N/cm or less, and further preferably 300N/cm or less, appropriate flexibility and processability can be obtained as a laminated nonwoven fabric which is particularly suitable for use in building material applications.

In the present invention, for the purpose of adjusting the thickness of the laminated nonwoven fabric, the thermal compression bonding can be performed by a pair of upper and lower smoothing rolls formed by a hot embossing roll before and/or after the thermal bonding by the hot embossing roll. The pair of upper and lower smoothing rolls are metal rolls or elastic rolls having no unevenness on the roll surface, and the metal rolls can be used in pairs or the metal rolls and the elastic rolls can be used in pairs.

Here, the elastic roller is a roller made of a material more elastic than the metal roller. Examples of the elastic roll include a so-called paper roll such as paper, cotton, and aramid paper, and a resin roll made of urethane resin, epoxy resin, silicone resin, polyester resin, and hard rubber, and a mixture thereof.

Examples

Next, a laminated nonwoven fabric of the present invention will be specifically described based on examples. In the measurement of each physical property, the measurement is not particularly described in the case of the above-described method.

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

regarding the MFR of the thermoplastic resin (A1) and the polyolefin resin (B), the MFR of the polypropylene resin (A1a) and that of the polyolefin resin (B) were measured under a load of 2.16kg and at a temperature of 230 ℃. The MFR of the polyethylene resin (A2) was measured under a load of 2.16kg and at a temperature of 190 ℃.

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

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

(3) Complex viscosity (Pa · sec):

a dynamic viscoelasticity measuring apparatus "RHEOSOL-G3000" was used to measure the complex viscosity (Pa sec) of the laminated nonwoven fabric under the conditions of 20mm parallel plates, a gap of 0.5mm, a temperature of 230 ℃, a strain of 34.9%, and a frequency of 0.3 to 63 rad/sec.

(4) Spinning speed (m/min):

the average single fiber diameter and the solid density of the polyolefin resin (a) or the polyolefin resin (B) used were calculated by rounding off the second decimal place with respect to the mass per 10,000m length as the average single fiber fineness (dtex). The spinning speed was calculated from the average single fiber fineness and the discharge amount of the resin discharged from the single hole of the spinneret (hereinafter, simply referred to as the discharge amount per single hole) (g/min) set under each condition based on the following formula.

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

(5) Water pressure resistance (mmH) of laminated nonwoven fabric₂O)：

A hydrostatic tester "Hydrotester" (FX-3000-IV) from TEXTEST, Switzerland was used.

(6) Air permeability per unit area weight ((cc/cm) of laminated nonwoven fabric²Second)(g/m²))：

The measurement of the air permeability was performed based on the method described above. The air permeability (cc/(cm))²Second)) and the weight per unit area (g/m) determined by the method described above²) The second decimal place is rounded off by the following formula, and the air permeability per unit area weight is calculated.

Air permeability (cc/(cm) — air permeability per unit area weight²Seconds))/weight per unit area (g/m)²)。

(7) Surface roughness SMD (μm) based on KES method of laminated nonwoven fabric:

in the measurement, an automated surface tester "KES-FB 4-AUTO-A" manufactured by Kato-Tech was used. The surface roughness SMD was measured on both sides of the laminated nonwoven fabric, and the smaller value of these was shown in table 1.

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

in the measurement, an automated surface testing machine "KES-FB 4-AUTO-A" manufactured by KatoTech was used. The average friction coefficient MIU was measured on both sides of the laminated nonwoven fabric, and the smaller value of these was shown in the table.

(9) Softness (processability) of nonwoven fabric:

as a sensory evaluation of the nonwoven fabric feel, softness was evaluated according to the following criteria. The nonwoven fabric was scored by 10 persons, and the average value thereof was evaluated as the touch of the nonwoven fabric. The higher the respective scores, the more excellent the flexibility and the better the workability in various working processes, and the score of 4.0 or more was regarded as acceptable.

< flexibility (processability) >

And 5, dividing: soft (good processability)

And 4, dividing: between 5 and 3 points

And 3, dividing: general purpose

And 2, dividing: intermediate between 3 and 1

1 minute: hard (poor processability).

[ example 1]

(spunbonded nonwoven Fabric layer (lower layer))

In the spunbonded nonwoven fabric layer, as the thermoplastic resin (A1), a polypropylene resin containing a homopolymer having an MFR of 170g/10 min and a melting point of 163 ℃ was used, and as the polyethylene resin (A2), a polyethylene resin (LLDPE) containing a homopolymer having an MFR of 100g/10 min was used. The thermoplastic resin (A1) and the polyethylene resin (A2) were each melted in an extruder and passed through a hole

A rectangular spinneret of 0.30mm and a hole depth of 2mm was spun at a spinning temperature of 235 ℃ and a discharge per hole of 0.43 g/min to form a core-sheath type cross section in which a thermoplastic resin (A1) was disposed as a core component and a polyethylene-based resin (A2) was disposed as a sheath component. After the spun sliver was cooled and solidified, it was drawn and stretched by compressed air having an ejector pressure of 0.50MPa in a rectangular ejector and collected on a moving web. The long fiber comprising the core-sheath composite fiber thus formed had a weight per unit area of 8.2g/m²A spunbond nonwoven layer. The average filament diameter of the fibers constituting the spunbond nonwoven fabric layer formed was 10.9 μm, and the spinning speed was 5,050 m/min in terms of the average filament diameter. Regarding the spinning property, no yarn breakage was observed in the 1 hour spinning, and thus it was good.

(meltblown nonwoven layer)

Next, as the polyolefin resin (B), a polypropylene resin containing a homopolymer having an MFR of 1100 g/min and a melting point of 163 ℃. Melting the polyolefin resin (B) in an extruder and extruding the melted polyolefin resin from the hole diameter

A spinneret of 0.25mm was spun at a spinning temperature of 260 ℃ and a discharge rate of 0.10 g/min per hole. Then, air was jetted to the sliver at an air temperature of 290 ℃ and an air pressure of 0.10MPa, and the air was collected on the spunbond nonwoven fabric layer to form a meltblown nonwoven fabric layer. At this time, under this condition, another collection to catch was carried outThe weight per unit area of the melt-blown nonwoven fabric layer on the collecting net was 1.6g/m²The average fiber diameter was 1.5. mu.m.

(spunbonded nonwoven Fabric layer (Upper layer))

The long fibers of the core-sheath composite fibers are collected on the meltblown nonwoven fabric layer under the same conditions as those for forming the lower spunbond nonwoven fabric layer, thereby forming a spunbond nonwoven fabric layer. Thus, a total basis weight of 18g/m was obtained²Spunbond-meltblown-spunbond laminated webs.

(laminated nonwoven Fabric)

Then, the resulting laminated fiber web was thermally bonded using an embossing roll made of metal and having a bead pattern engraved bonding area ratio of 16% for the upper roll and an upper and lower pair of heat embossing rolls made of a metal smoothing roll for the lower roll under conditions of a line pressure of 300N/cm and a thermal bonding temperature of 120 ℃ to obtain a weight per unit area of 18g/m²The laminated nonwoven fabric of (1). The obtained laminated nonwoven fabric was measured for thickness, apparent density, water pressure resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient, and the flexibility of the laminated nonwoven fabric was further evaluated. The results are shown in Table 1.

[ example 2]

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer comprising core-sheath conjugate fibers was formed in the same manner as in example 1, except that a polypropylene resin comprising a homopolymer having an MFR of 300g/10 min and a melting point of 163 ℃. Regarding the characteristics of the long fibers constituting the spunbond nonwoven fabric layer formed, the average single fiber diameter was 10.5 μm, and the spinning speed was 5,500 m/min in terms of the average single fiber diameter. Regarding the spinning property, no yarn breakage was observed in the 1 hour spinning, and thus it was good.

(meltblown nonwoven layer)

A meltblown nonwoven fabric layer was formed in the same manner as in example 1. With respect to the characteristics of the fibers constituting the formed meltblown nonwoven fabric layer, the average fiber diameter was 1.5 μm.

(laminated nonwoven Fabric)

A laminated nonwoven fabric was obtained in the same manner as in example 1. The obtained laminated nonwoven fabric was measured for thickness, apparent density, water pressure resistance, air permeability per unit area weight, complex viscosity, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient, and the flexibility of the laminated nonwoven fabric was further evaluated. The results are shown in table 1.

[ example 3]

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer comprising core-sheath conjugate fibers was formed in the same manner as in example 1, except that a polypropylene resin comprising a homopolymer having an MFR of 800g/10 min and a melting point of 163 ℃. Regarding the characteristics of the long fibers constituting the spunbond nonwoven fabric layer formed, the average single fiber diameter was 9.8 μm, and the spinning speed was 6,300 m/min in terms of the average single fiber diameter. Regarding the spinning property, no yarn breakage was observed in the 1 hour spinning, and thus it was good.

(meltblown nonwoven layer)

A meltblown nonwoven fabric layer was formed in the same manner as in example 2.

(laminated nonwoven Fabric)

[ example 4]

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in example 1, except that the cell discharge amount was 0.21 g/min. Regarding the characteristics of the fibers constituting the formed spunbond nonwoven fabric layer, the average filament diameter was 7.4 μm, and the spinning speed was 5,700 m/min in terms of the average filament diameter.

(meltblown nonwoven layer)

A meltblown nonwoven fabric layer web was obtained in the same manner as in example 1.

(laminated nonwoven Fabric)

[ example 5]

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

Except that the unit area weight was set to 8.5g/m²Except for this, a spunbond nonwoven fabric layer was obtained in the same manner as in example 4.

(meltblown fiber web)

The air pressure was set to 0.20MPa, and the unit area weight was set to 1.0g/m²Except for this, a meltblown nonwoven fabric layer was obtained in the same manner as in example 1. With respect to the characteristics of the fibers constituting the obtained meltblown nonwoven fabric layer, the average fiber diameter was 1.0 μm.

(laminated nonwoven Fabric)

[ example 6]

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in example 1, except that 1.0 mass% of ethylene bisstearoyl distearate was added to the polyethylene resin (a2) so that the amount of the resin added to the entire spunbond nonwoven fabric layer was 0.3 mass%.

(meltblown nonwoven layer)

A meltblown nonwoven fabric layer was obtained in the same manner as in example 1.

(laminated nonwoven Fabric)

Comparative example 1

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in example 1, except that a homopolypropylene resin having an MFR of 60g/10 min and a melting point of 163 ℃ was used as the thermoplastic resin (a1), and the ejector pressure was 0.15 MPa. Regarding the characteristics of the long fibers constituting the obtained core-sheath nonwoven fabric layer, the average single fiber diameter was 18.0 μm, and the spinning speed was 1,900 m/min in terms of the average single fiber diameter. The spinnability was poor because 11 yarn breaks occurred during 1 hour of spinning.

(meltblown nonwoven layer)

(laminated nonwoven Fabric)

A laminated nonwoven fabric was obtained in the same manner as in example 1. The obtained laminated nonwoven fabric was measured for thickness, apparent density, water pressure resistance, air permeability per unit area weight, surface roughness SMD, average friction coefficient MIU, and variation MMD of average friction coefficient, and the flexibility of the laminated nonwoven fabric was further evaluated. The results are shown in Table 1.

Comparative example 2

(spunbonded nonwoven Fabric layer (lower layer) · (upper layer))

A spunbond nonwoven fabric layer was obtained in the same manner as in example 1, except that a homopolyethylene resin having an MFR of 20g/10 min was used as the polyethylene resin (a2) and the ejector pressure was 0.15 MPa. The long fibers constituting the obtained core-sheath nonwoven fabric layer had an average single fiber diameter of 17.4 μm and a spinning speed of 1,900 m/min in terms of the average single fiber diameter. The spinnability was poor because 9 yarn breaks occurred during 1 hour of spinning.

(meltblown nonwoven layer)

(laminated nonwoven Fabric)

[ Table 1]

In examples 1 to 6, the surface roughness SMD by the KES method was 1.8 to 2.1 μm, and the water pressure resistance per unit area weight was 15mmH₂O/(g/m²) Thereby having excellent water resistance. The laminated nonwoven fabric of example 6, in which ethylene bis stearamide was added to the fibers constituting the spunbond nonwoven fabric layer, had a reduced average friction coefficient, increased flexibility and excellent processability, and was particularly suitable as a nonwoven fabric for house wrap.

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.

The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. It should be noted that the present application is based on japanese patent application filed on 28/2/2018 (japanese application 2018-034870) and japanese patent application filed on 27/7/2018 (japanese application 2018-141051), the entire contents of which are incorporated herein by reference.

Industrial applicability

The laminated nonwoven fabric of the present invention has high productivity, uniform texture, smooth surface, excellent hand and skin touch, and high water resistance, and therefore can be suitably used as a moisture-permeable waterproof sheet for building materials.

The use of the laminated nonwoven fabric of the present invention is not limited to the above, and the laminated nonwoven fabric can be used for industrial materials such as filters, filter substrates, and wire wrapping materials, building materials such as wall papers, roof underlayment materials, sound insulation materials, heat insulation materials, and sound absorbing materials, living materials such as packaging materials, bag materials, advertisement board materials, and printing substrates, civil engineering materials such as weed control sheets, drainage materials, foundation reinforcement materials, sound insulation materials, and sound absorbing materials, agricultural materials such as covering materials and light shielding sheets, and vehicle materials such as ceiling materials and spare tire cover materials.

Description of the reference numerals

(a) The method comprises the following steps Core part

(b) The method comprises the following steps Sheath part

(c) The method comprises the following steps Component 1

(d) The method comprises the following steps Component 2

Claims

1. A laminated nonwoven fabric comprising a spunbonded nonwoven fabric layer and a meltblown nonwoven fabric layer laminated together, wherein the spunbonded nonwoven fabric layer is composed of composite fibers comprising a thermoplastic resin (A1) and a polyethylene resin (A2), the thermoplastic resin (A1) is a polyolefin resin (A1a) or a polyester resin (A1B), the meltblown nonwoven fabric layer is composed of fibers comprising a polyolefin resin (B), the composite fibers of the spunbonded nonwoven fabric layer have an average filament diameter of 6.5 to 11.9 [ mu ] m, and the spunbonded nonwoven fabric layer has a complex viscosity of 100Pa sec or less as measured at 230 ℃ and 6.28 rad/sec.

2. The laminated nonwoven fabric according to claim 1, having a water pressure resistance of 15mmH per unit weight₂O/(g/m²) The above.

3. The laminated nonwoven fabric according to claim 1 or 2, wherein the melt flow rate of the fibers comprising the thermoplastic resin (A1) constituting the spunbonded laminated nonwoven fabric is 155 to 850g/10 min.

4. A laminated nonwoven fabric as claimed in any one of claims 1 to 3, wherein the content of the meltblown nonwoven fabric layer is 1 mass% or more and 15 mass% or less with respect to the mass of the laminated nonwoven fabric.

5. A laminated nonwoven fabric according to any one of claims 1 to 4, which has a surface roughness SMD of 1.0 to 2.6 μm based on the KES method on at least one side.

6. A laminated nonwoven fabric as claimed in any one of claims 1 to 5, which has an average coefficient of friction MIU based on the KES method of 0.1 to 0.5 on at least one side.

7. The laminated nonwoven fabric according to any one of claims 1 to 6, wherein the MMD of the variation of the average friction coefficient of at least one surface of the laminated nonwoven fabric according to the KES method is 0.008 or less.

8. The laminated nonwoven fabric according to any one of claims 1 to 7, wherein the polyethylene resin (A2) contains a fatty acid amide compound having 23 or more and 50 or less carbon atoms.

9. The laminated nonwoven fabric according to claim 8, wherein the fatty acid amide compound is added in an amount of 0.01 to 5.0 mass%.

10. The laminated nonwoven fabric according to claim 8 or 9, wherein the fatty acid amide compound is ethylene bisstearamide.