TW201923190A - Spunbonded nonwoven fabric - Google Patents

Abstract

A spunbonded nonwoven fabric of the present invention is characterized by being composed of a polyolefin fiber, wherein the average pore diameter of the nonwoven fabric surface is 0.1-25 [mu]m, the maximum pore diameter is 50 [mu]m or less, and the water pressure resistance per unit basis weight is 7 mmH2O/(g/m2) or more.

Description

   Spunbond Nonwoven   

The present invention relates to a spunbond nonwoven fabric, which contains polyolefin fibers, is excellent in water resistance and flexibility, and is excellent in formability as a building material.

In recent years, non-woven fabrics have been used in various applications, and they are expected to grow in the future. Nonwovens are used in a wide range of applications including industrial materials, civil materials, construction materials, living materials, agricultural materials, sanitary materials, and medical materials.

For non-woven use, focus on building materials. In recent years, in wooden houses and other buildings, a ventilation layer is provided between the outer wall material and the heat insulation material, and the ventilation layer construction method that discharges moisture invading the body through the ventilation layer to the outside is being spread. In this ventilation layer construction method, a spunbond non-woven fabric is used as a covering material for the moisture-permeable waterproof sheet, which has both the waterproofness to prevent rainwater from penetrating from the outside of the building and the moisture generated in the wall to escape to the outside. The moisture permeability. Although the spunbond nonwoven fabric has the characteristics of excellent moisture permeability in terms of its structure, it has the disadvantage of poor water resistance. Therefore, it is laminated and integrated with a film excellent in water resistance to form a moisture-permeable waterproof sheet, which is used as a covering material for a house.

The housing covering material is fixed by a pin (also known as a staple or staple) and is applied to the substrate. It requires long-term durability or excellent weather resistance under high temperature and low temperature conditions, and can withstand long-term use. Durability (hydrolysis resistance) and excellent moldability during construction.

In the past, as a moisture-permeable waterproof sheet used in such a house covering material, in order to achieve a good balance between moisture permeability and water resistance, a house covering material was proposed, which uses a fiber diameter of 3 to 28 microns and a unit Polyester-based non-woven fabric with an area weight of 5 to 50 g / m ^{2. On} this non-woven fabric, a laminated film composed of a block copolymerized polyester having a hard segment and a soft segment having a thickness of 7 to 60 μm is formed. (See Patent Document 1).

    [Prior technical literature]         [Patent Literature]    

Patent Document 1: Japanese Invention Patent No. 3656837

However, the conventional house cladding material is a laminated body of a non-woven fabric and a film, and therefore, there are problems that the sheet is hard and the formability is poor. The difference in the hardness or formability of the sheet is caused by the film. Although it is effective to reduce the proportion of the laminated film, from the viewpoint of waterproofness, the reduction of the proportion of the film is limited.

As described above, a nonwoven fabric having both water resistance and flexibility and excellent formability has been required in the past.

Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a spunbond non-woven fabric, which is a non-woven fabric composed of a polyolefin-containing fiber, and has excellent water-repellency and flexibility, as compared with the conventional technology.

The spunbond nonwoven fabric of the present invention is a spunbond nonwoven fabric composed of polyolefin fibers, which is characterized in that the average of the pore size of the non-woven fabric is 0.1 to 25 μm, and the maximum value of the pore size of the non-woven fabric is 50 μm or less. The water pressure resistance is 7 mmH ₂ O / (g / m ² ) or more.

According to a preferred aspect of the laminated nonwoven fabric of the present invention, the average single fiber diameter of the aforementioned polyolefin fibers constituting the spunbond nonwoven fabric is 6.5 to 11.9 μm.

According to a preferred aspect of the laminated nonwoven fabric of the present invention, the dynamic friction coefficient of the aforementioned polyolefin fibers constituting the spunbonded nonwoven fabric is 0.01 to 0.3.

According to a preferred aspect of the spunbond nonwoven fabric of the present invention, the melt flow rate of the aforementioned spunbond nonwoven fabric is 155 to 850 g / 10 minutes.

According to a preferred aspect of the spunbonded nonwoven fabric of the present invention, the aforementioned polyolefin-based resin contains a fatty acid amido compound having a carbon number of 23 to 50.

According to a preferred aspect of the spunbonded nonwoven fabric of the present invention, the amount of the aforementioned fatty acid amido compound is 0.01 to 5.0% by mass.

According to a preferred aspect of the spunbond non-woven fabric of the present invention, the aforementioned fatty acid amido compound is ethynylbisstearate.

According to the present invention, a spunbond non-woven fabric is obtained, which contains polyolefin fibers with good spinnability and high productivity although the diameter of the single fiber is fine. The texture is uniform, the surface is smooth and the softness is excellent, and the pore size of the non-woven fabric is small. Has high water resistance. Due to these characteristics, the spunbond nonwoven fabric of the present invention is particularly suitable for use as a moisture-permeable waterproof sheet.

    [Form of Implementing Invention]    

The spunbond nonwoven fabric of the present invention is a spunbond nonwoven fabric composed of polyolefin fibers, which is characterized in that: the average pore size of the nonwoven fabric is 0.1 to 25 μm, and the maximum value of the pore size is 50 μm or less; It is 7 mmH ₂ O / (g / m ² ) or more.

By doing so, it can become a spunbond nonwoven fabric with a small pore size on the surface of the nonwoven fabric and excellent water resistance, and a spunbond nonwoven fabric with the required level of waterproofness and processability required for moisture-permeable waterproof sheets such as house covering materials.

As the polyolefin resin used in the present invention, examples of the polypropylene resin include homopolymers of propylene or copolymers of propylene and various α-olefins, and examples of the polyethylene resin include homopolymers of ethylene. Polypropylene resins are particularly preferred from the viewpoint of spinnability or strength characteristics, such as copolymers of ethylene and various α-olefins.

With regard to the polyolefin-based resin 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 even more preferably 80% by mass or more. This makes it possible to maintain good spinnability and increase strength.

The polyolefin-based resin used in the present invention may be a mixture of two or more kinds, and a resin composition containing other olefin-based resins or thermoplastic elastomers may also be used.

The melt flow rate (also referred to as MFR) of the polyolefin resin used in the spunbonded nonwoven fabric of the present invention (polypropylene: ASTM D1238 load: 2160g, temperature: 230 ° C, polyethylene: ASTM D1238 load: 2160g, temperature: 190 ° C ) Is preferably 155 to 850 g / 10 minutes, more preferably 155 to 600 g / 10 minutes, and even more preferably 155 to 400 g / 10 minutes. In addition, two or more resins having different MFRs may be blended in an arbitrary ratio to adjust the MFR of the polyolefin resin. By setting the MFR to be in the range of 155 to 850 g / 10 minutes, stable spinning is easy, and the orientation crystallization system is easy to perform, and high-strength fibers are easily obtained.

Of course, two or more resins having different MFRs may be blended at any ratio to adjust the MFR of the polyolefin resin. At this time, the MFR of the resin blended with the main polyolefin-based 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 doing so, it is possible to prevent the occurrence of unevenness in viscosity, unevenness in fineness, and deterioration in spinnability in the blended polyolefin resin.

In addition, when spinning the fibers described later, in order to prevent uneven viscosity from occurring, the fiber fineness is made uniform, and the fiber diameter is reduced as described later. It is also considered that the resin used is decomposed to adjust the MFR. However, for example, it is preferable not to add a peroxide, especially a radical agent such as a dialkyl peroxide. When this method is used, uneven viscosity and uneven fineness sometimes occur, it is difficult to sufficiently refine the fiber diameter, and the spinnability may be deteriorated due to uneven viscosity or bubbles caused by decomposed gas.

In the present invention, a composite fiber in which the above-mentioned polyolefin resin is combined may be used. Examples of the composite form of the composite fiber include a composite form such as a concentric core sheath type, an eccentric core sheath type, and a sea-island type. Among them, a concentric core-sheath type composite form is preferable in terms of excellent spinnability, and because a low-melting point component is disposed in the sheath component, the fibers can be bonded to each other uniformly by heat bonding.

In the polyolefin-based resin used in the present invention, as long as the effects of the present invention are not impaired, commonly used antioxidants, weather-resistant stabilizers, light-resistant stabilizers, antistatic agents, anti-fog agents, and anti-sticking agents can be added as needed. Additives such as coupling agents, lubricants, nucleating agents and pigments, or other polymers.

The melting point of the polyolefin resin used in the present invention is preferably 80 to 200 ° C, more preferably 100 to 180 ° C, and even more preferably 120 to 180 ° C. The melting point is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and even more preferably 120 ° C. or higher, and it is easy to obtain practical heat resistance. Furthermore, the melting point is preferably 200 ° C. or lower, and more preferably 180 ° C. or lower, so that the sliver ejected from the spinneret is easily cooled, the fusion between the fibers is suppressed, and stable spinning is easily performed.

The polyolefin fibers constituting the spunbond nonwoven fabric used in the present invention preferably have an average single fiber diameter of 6.5 to 11.9 μm. By setting the average single fiber diameter to preferably 6.5 μm or more, more preferably 7.5 μm or more, and even more preferably 8.4 μm or more, it is possible to prevent a decrease in spinnability and to stably produce a good quality nonwoven fabric. On the other hand, by setting the average single fiber diameter to 11.9 μm or less, more preferably to 11.2 μm or less, and even more preferably to 10.6 μm or less, the uniformity of the surface of the non-woven fabric can be improved. It is a spunbond non-woven fabric with excellent water resistance.

The CV value of the single fiber diameter of the polyolefin fibers constituting the spunbonded nonwoven fabric used in the present invention is preferably 0.1 to 7.0%. By setting the CV value of the single fiber diameter to preferably 0.1% or more, more preferably 1.0% or more, and even more preferably 2.0% or more, it is possible to prevent the production equipment from being complicated or the productivity from being extremely reduced. On the other hand, by setting the CV value of the single fiber diameter to 7.0% or less, more preferably 6.0% or less, and even more preferably 5.0% or less, it is possible to prevent the surface from having a rough feeling and to have a high uniformity. Laminated non-woven fabric. The uniformity of the spinneret's back pressure, yarn cooling conditions, and elongation conditions affects the CV value of the single fiber diameter, and can be controlled by appropriately adjusting these.

The MFR of the polyolefin fibers constituting the spunbond nonwoven fabric used in the present invention is preferably 155 to 850 g / 10 minutes. The MFR is preferably 155 to 850 g / 10 minutes, more preferably 155 to 600 g / 10 minutes, and even more preferably 155 to 400 g / 10 minutes, even at high spinning speeds for improving productivity. It can also easily follow deformation, and it can spin stably. In addition, since it can be stretched stably at a fast spinning speed, the orientation crystallization of the fibers can be promoted, and polyolefin fibers having high mechanical strength can be obtained.

In the spunbond non-woven fabric of the present invention, in order to improve the sliding properties of the fibers, or the sliding property or softness in terms of feel, the polyolefin-based fibers made of a polyolefin-based resin that belong to the fibers contain carbon numbers. Fatty acid ammonium compounds of 23 to 50 are preferred.

It is known that the carbon number of the fatty acid amido compound mixed in the polyolefin fiber causes the moving speed of the fatty acid amido compound to the fiber surface to change. By setting the carbon number of the fatty acid amido compound to preferably 23 or more, and more preferably 30 or more, it is possible to prevent the fatty acid amido compound from being excessively exposed on the surface of the fiber, and to be excellent in spinnability and processing stability, and can be maintained High productivity, while capturing as a spunbond nonwoven web, can impart moderate slip to the fibers, achieve uniformity of the surface of the nonwoven, and reduce the diameter of the surface of the nonwoven. On the other hand, by setting the carbon number of the fatty acid amido compound to preferably 50 or less, and more preferably to 42 or less, the fatty acid amido compound becomes easier to move to the surface of the fiber, and it is possible to impart the slip properties of the spunbond nonwoven fibers to each other or Sliding and softness of non-woven surface.

Examples of the fatty acid sulfonamide compounds having a carbon number of 23 to 50 used in the present invention include saturated fatty acid monofluorene compounds, saturated fatty acid diamine compounds, unsaturated fatty acid monoamine compounds, and unsaturated fatty acid diamine compounds. Wait.

Specifically, as the fatty acid ammonium compound having a carbon number of 23 to 50, ammonium tetracosamate, ammonium hexacosanoate, ammonium octadecanoate, ammonium tetracosenoate, Ammonium hexapentaenoate, ammonium hexahexaenoate, ammonium dilaurate, ammonium dilaurate, ammonium distearate, ethanamine Methylbishydroxystearate, hexamethylenebis behenate, hexamethylenebisstearate, hexamethylenebis behenate, hexamethylenehydroxystearate Ammonium distearate, ammonium distearyl adipate, ammonium distearyl sebacate, ammonium bisoleate, ammonium bisinaecate, and hexamethylene double oil Acid amines and the like may be used in combination of a plurality of them.

In the present invention, among these fatty acid amido compounds, it is particularly preferable to use a saturated fatty acid diamidine compound. Ethylene bis-stearate can be melt-spun due to its excellent thermal stability. By blending polyolefin fibers with this bis-stearate, it is possible to maintain high productivity while maintaining high productivity. When capturing as a spunbond nonwoven web, the fibers can be imparted with a moderate sliding property to achieve uniformity of the surface of the nonwoven and reduce the diameter of the pores on the surface of the nonwoven.

In the present invention, for the polyolefin fibers constituting the spunbonded nonwoven fabric made of the polyolefin resin, the addition amount of the fatty acid amide compound is preferably 0.01 to 5.0% by mass. By setting the amount of the fatty acid amido compound to be 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, it is possible to maintain the spinnability while maintaining the spinnability. When the spunbond non-woven fabric is captured, the fibers can be imparted with a moderate sliding property to achieve uniformity of the surface of the non-woven fabric and reduce the diameter of the surface of the non-woven fabric.

The added amount mentioned here refers to the mass percentage of the fatty acid amidamine compound added to the polyolefin-based fibers constituting the spunbonded nonwoven fabric of the present invention, specifically to the entire resin constituting the polyolefin fibers. For example, even when the fatty acid amido compound is added only to the sheath component constituting the core-sheath composite fiber, the addition ratio to the total amount of the core-sheath component is calculated.

The kinetic friction coefficient of the fibers constituting the spunbonded nonwoven fabric of the present invention is preferably 0.01 or more and 0.3 or less. By setting the coefficient of dynamic friction to 0.01 or more, and preferably 0.1 or more, the fibers can be slipped with each other. When the spunbond nonwoven web is captured, the fibers can slide with each other moderately, thereby improving the uniformity of the surface of the nonwoven. By setting the coefficient of dynamic friction to 0.3 or less, preferably 0.25 or less, the surface of the non-woven fabric is not slippery, and the workability and handling properties when used as a non-woven fabric for building materials are improved. The dynamic friction coefficient of the spunbond fibers can be controlled by the type of polymer, the diameter of the single fiber, the type or amount of the lubricant added to the fiber, and the shape of the fiber.

It is important that the water pressure per unit area weight of the spunbonded nonwoven fabric of the present invention is 7 mmH ₂ O / (g / m ² ) or more. By setting the water pressure resistance per unit area weight to 7 mmH ₂ O / (g / m ² ) or more, preferably 8 mmH ₂ O / (g / m ² ) or more, and more preferably 9 mmH ₂ O / (g / m ² ) or more, in applications requiring low water resistance, it can be used as a moisture-permeable waterproof sheet for spunbond non-woven fabrics, and it can reduce the proportion of the film to be bonded in the bonding with the film, which can suppress the A decrease in moisture permeability due to a film or a decrease in workability due to a decrease in sheet feel. In addition, in order to prevent spunbonded nonwoven fabrics from being densified due to high density and reduced flexibility, damage to processability for use as a building material, or reduction in productivity due to fine fiber formation, the water pressure resistance per unit area weight is preferably 20 mmH ₂ O / (g / m ² ) or less. The hydraulic pressure resistance per unit area weight can be adjusted by the single fiber diameter, the pore diameter of the non-woven fabric surface, the apparent density, and the thermal compression bonding conditions (crimping rate, temperature, and line pressure).

It is important that the maximum pore diameter of the surface of the spunbonded nonwoven fabric of the present invention is 50 μm or less. By setting the maximum pore diameter to 50 μm or less, preferably 45 μm or less, and more preferably 40 μm or less, it is possible to prevent a reduction in water pressure resistance due to a partial opening. The lower limit of the maximum pore size is not particularly limited, but in order to prevent the spunbond nonwoven fabric from being densified and softened, the use of the material as a building material has reduced workability, and the maximum pore size is preferably 0.1 m or more. The maximum pore diameter of the non-woven fabric can be controlled by the diameter of the single fiber, the dispersed state of the fibers, the coefficient of dynamic friction between the single fibers, the weight per unit area of the non-woven fabric, thermal bonding conditions (temperature, pressure) and the like.

It is important that the average pore diameter of the surface of the spunbonded nonwoven fabric of the present invention is 0.1 μm or more and 25 μm or less. By setting the average pore size to be 0.1 μm or more, preferably to be 0.5 μm or more, and more preferably to be 1 μm or more, the spunbond nonwoven fabric can be moderately softened. By setting the average pore size to 25 μm or less, preferably 23 μm Hereinafter, it is more preferably 21 μm or less, and high water resistance characteristics can be exhibited. The average pore diameter of the non-woven fabric can be controlled by the diameter of the single fiber, the dispersion state of the fibers, the coefficient of dynamic friction between the single fibers, the weight per unit area of the non-woven fabric, thermal bonding conditions (temperature, pressure), and the like.

The weight per unit area of the spunbond nonwoven fabric of the present invention is preferably 10 to 100 g / m ² . By weight of the preferred set 10g / m ² or more, more preferably set to 13g / m ² or more, and particularly preferably set to 15g / m ² or more, obtained withstand practical mechanical strength of the spunbond nonwoven fabric. On the other hand, the basis weight 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. When used as a housing covering material, It is suitable for the operator to hold the weight during construction, and it can be a laminated non-woven fabric with excellent operability during construction. Moreover, when it is used for other uses, it can also be a laminated nonwoven fabric excellent in handleability.

The thickness of the spunbond nonwoven fabric of the present invention is preferably 0.05 to 1.50 mm. The thickness is preferably 0.05 to 1.50 mm, more preferably 0.08 to 1.00 mm, and even more preferably 0.10 to 0.80 mm. It has flexibility and moderate cushioning properties. When used as a housing covering material, it becomes It is suitable for the weight of the operator during hand-held work during construction, and can be a laminated non-woven fabric with excellent operability during construction.

The apparent density of the spunbond nonwoven fabric of the present invention is preferably 0.05 to 0.30 g / cm ³ . With the apparent density is preferably set to 0.30g / cm ³ or less, more preferably to 0.25g / cm ³ or less, and particularly preferably set to 0.20g / cm ³ or less to prevent damage to the fiber filled densely spunbond nonwoven fabric Soft people. On the other hand, by the apparent density is preferably set to 0.05g / cm ³ or more, more preferably set to 0.08g / cm ³ or more, and particularly preferably set to 0.10g / cm ³ or more, can suppress the interlayer peeling or fluffing Occurs and becomes a spunbond non-woven fabric with strength or softness that can withstand practical use.

The 5% elongation stress (hereinafter, also referred to as 5% modulus per unit area weight) of the spunbond nonwoven fabric of the present invention is preferably 0.06 to 0.33 (N / 25mm) / (g / m ² ), More preferably 0.13 to 0.30 (N / 25mm) / (g / m ² ), and particularly preferably 0.20 to 0.27 (N / 25mm) / (g / m ² ). By doing so, it becomes a spunbond non-woven fabric that is soft and excellent in touch while maintaining practical strength.

Furthermore, in the present invention, the 5% elongation stress per unit area weight of the spunbond nonwoven fabric is based on "6.3 Tensile Strength and Elongation (ISO Method)" in accordance with JIS L1913: 2010, and is determined by the following procedure: Measured value.

(1) In each of the longitudinal direction (longitudinal direction of the non-woven fabric) and the transverse direction (widthwise direction of the non-woven fabric), a test piece of 25 mm × 300 mm in three pieces was collected at a width of 1 m.

(2) The test piece was fixed to a tensile tester with a clamp interval of 200 mm.

(3) A tensile test was performed at a tensile speed of 100 mm / minute, and the stress (5% modulus) at 5% elongation was 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 weight according to the following formula, and round the third place below the decimal point.

‧Module of 5% weight per unit area ((N / 25mm) / (g / m ² )) = [Average value of 5% modulus (N / 25mm)] / Unit weight (g / m ² ).

Next, a preferable aspect of the method for manufacturing the spunbonded nonwoven fabric of the present invention will be specifically described.

The spunbond nonwoven fabric of the present invention is a long-fiber nonwoven fabric manufactured by the spunbond (S) method. Examples of the manufacturing method of the non-woven fabric include a spunbond method, a flash spinning method, a wet method, a carding method, and an airlaid method. However, the spunbond method is excellent in productivity or mechanical strength, and can be suppressed in short fibers. Non-woven fabrics are prone to fluff or fiber shedding. In addition, by spunbonding (S) non-woven fabric layers laminated with SS, SSS, and SSSS, it is a preferable aspect because productivity or texture uniformity is improved.

In the spunbond method, first, a molten thermoplastic resin (polyolefin resin) is spun out of a spinning spinneret to grow fibers, and then ejected with compressed air by an ejector. Fibers are trapped on the net without woven fibers being networked. Furthermore, heat treatment was performed on the obtained nonwoven fiber web to obtain a spunbond nonwoven fabric.

As the shape of the spinneret or ejector, various shapes such as a circle or a rectangle can be adopted. Among them, the use of compressed air is relatively small and the energy cost is excellent. It is not easy to cause fusing or friction of the slivers, and the fiber opening of the slivers is also easy to see. A combination of a rectangular spinneret and a rectangular ejector is more suitable.

In the present invention, a polyolefin-based resin is melted in an extruder, measured, supplied to a spinneret, and spun out as long fibers. The spinning temperature when melt-spinning a polyolefin resin is preferably 200 to 270 ° C, more preferably 210 to 260 ° C, and even more preferably 220 to 250 ° C. By setting the spinning temperature within the above range, a stable molten state can be obtained, and excellent spinning stability can be obtained.

The back pressure of the spinneret is preferably set to 0.1 to 6.0 MPa. By setting the back pressure to be preferably 0.1 to 6.0 MPa, more preferably 0.3 to 6.0 MPa, and even more preferably 0.5 to 6.0 MPa, it is possible to prevent the deviation of the fiber diameter from occurring due to poor discharge uniformity, or to improve the pressure resistance. Sexual and spinnerets are large. The back pressure of the spinneret can be adjusted by the ejection hole diameter, the ejection hole depth, and the spinning temperature of the spinneret, among which the contribution of the ejection hole diameter is large.

The slivers of the spun long fibers are then cooled. As a method of cooling the spun yarn, for example, a method of forcibly blowing cold air onto the yarn, a method of naturally cooling the environment temperature around the yarn, and adjusting the spinning nozzle and the The method of the distance between the injectors, etc., or a method of combining these methods may be adopted. In addition, the cooling conditions can be appropriately adjusted by taking into consideration the discharge amount per single hole of the spinneret, the spinning temperature, and the ambient temperature. However, in the method of forcibly blowing cold wind onto the sliver, it is preferable that the deviation of the wind speed when measuring 10 points at an interval in the width direction in the blowing area is 25% or less. By setting the wind speed deviation to 25% or less, more preferably to 20% or less, and even more preferably to 15% or less, the sliver can be uniformly cooled, and fibers having a small single fiber CV can be obtained. The wind speed deviation referred to in the present invention can be calculated by the following formula.

‧Wind speed deviation (%) = (Maximum wind speed-Minimum wind speed) / Average wind speed × 100

Next, the cooled and solidified sliver is drawn and stretched by the compressed air ejected from the ejector.

The spinning speed is preferably 3500-6500m / min, more preferably 4000-6500m / min, and even more preferably 4500-6500m / min. By setting the spinning speed to 3500 to 6500 m / min, it has high productivity, and it can promote the orientation crystallization of the fibers to obtain high-strength long fibers. Generally, if the spinning speed is increased, the spinnability is deteriorated and the sliver cannot be produced stably. However, by using a polyolefin resin having a specific range of MFR as described above, the intended polyolefin fiber can be stably spun.

Then, the obtained long fibers were collected on a moving web without being woven into a web. In the present invention, since the fiber is drawn at a high spinning speed, the fiber system coming out of the ejector is ejected at a high speed. The spun spun-bonded non-woven fabric with less entanglement of fibers and high uniformity can be obtained by opening the fibers under the controlled state of the sliver sprayed at a high speed in this manner.

As a method for opening fibers in a controlled state of the sliver ejected from the ejector, a method of setting a flat plate with an angle between the ejector and the mesh to induce the sliver can be cited. Set a plurality of grooves with different angles, and separate them into slivers that fall along the flat plate and slivers that fall along the groove, and disperse and open the fiber in the direction of flow of the nonwoven web, and comb the teeth at the exit of the ejector. A method of arranging a plurality of flat plates with different angles so that the slivers fall along the respective flat plates, and dispersing and opening fibers in the flow direction of the nonwoven fiber web.

Among them, from the viewpoint that the sliver of fine fiber diameter can be efficiently dispersed in the flow direction of the nonwoven fiber web, and the fiber is opened in a controlled state without deceleration as much as possible, the preferred aspect is at the ejector exit A method of arranging a plurality of flat plates with different angles in a comb-tooth shape, and making the yarn fall along the respective flat plates to open the fiber.

In addition, in the present invention, the non-woven fiber web is abutted against a hot flat roll from one side of the web to make it a temporary contactor. By doing so, it is possible to prevent the surface layer of the nonwoven fibrous web from being rolled up or fluttering during the web conveyance, thereby deteriorating the texture, and it is possible to improve the conveyability from the yarn collection to the thermocompression bonding.

Then, the obtained nonwoven fiber web is integrated by heat and then the intended spunbond nonwoven fabric can be obtained.

As a method for integrating the nonwoven fiber web by heating, the hot embossing rolls each having an engraving (concavo-convex portion) on the upper and lower pair of roller surfaces can be used. One roller surface is flat. A hot embossing roll composed of a combination of a (smooth) roll and a roll with engraving (concavo-convex portions) on the surface of another roll, and a heat calender composed of a combination of a pair of flat (smooth) rolls on the top and bottom Various methods, such as rollers, are used for thermal bonding; or ultrasonic bonding for thermal welding by ultrasonic vibration of a horn. Among them, from the viewpoint of excellent productivity, strength can be imparted to a portion of the heat-adhesive portion, and a non-woven touch or skin feel can be maintained in the non-adhesive portion. Hot embossing roller with engraving (concavo-convex portion), or a heat embossing roller composed of a combination of a roller with a flat (smooth) roller surface and a roller with engraving (concavo-convex portion) on the other roller surface .

As the surface material of the heat embossing roller, in order to obtain a sufficient heat compression bonding effect, and to prevent the engraving (concave and convex portion) of one embossing roller from being transferred to the surface of the other roller, a preferable aspect is to make a metal roller Paired with metal rolls.

The area ratio of embossing adhesion caused by such a hot embossing roll is preferably 5 to 30%. By setting the bonding area to preferably 5% or more, more preferably 8% or more, and even more preferably 10% or more, practical strength can be obtained as a spunbond nonwoven fabric. On the other hand, by setting the bonding area to be preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less, a spunbond nonwoven fabric suitable for use as a sanitary material can be obtained, and particularly suitable for use in building materials. Moderate softness and handleability for use. When using ultrasonic bonding, the bonding area ratio is also preferably in the same range.

The bonding area ratio mentioned here refers to the ratio of the bonding portion to the entire spunbond nonwoven fabric. Specifically, when thermal bonding is performed by a pair of rollers having unevenness, the portion (adhesion portion) of the convex portion of the upper roller and the convex portion of the lower roller that abuts against the nonwoven web occupies the spunbond nonwoven fabric. Proportion of the whole. In addition, when thermal bonding is performed by a roll having unevenness and a flat roll, a portion (adhesion portion) where the convex portion of the roll having unevenness abuts on the nonwoven fiber web accounts for the entire spunbonded nonwoven fabric. In addition, when performing ultrasonic bonding, it refers to the proportion of the portion (adhesion portion) thermally welded by ultrasonic processing to the entire spunbond nonwoven fabric.

As the shape of the bonding portion caused by the hot embossing roll or the ultrasonic bonding, a circle, an oval, a square, a rectangle, a parallelogram, a rhombus, a regular hexagon, a regular octagon, and the like can be used. Moreover, it is preferable that an adhesion part exists uniformly at a fixed space | interval in each of the longitudinal direction (conveying direction) and the width direction of a spunbond nonwoven fabric. By doing so, the variation in the strength of the spunbond nonwoven fabric can be reduced.

The surface temperature of the hot embossing roller at the time of thermal bonding is preferably in a range of -50 to -15 ° C relative to the melting point of the polyolefin resin used. With respect to the melting point of the polyolefin resin, the surface temperature of the heat roller is preferably -50 ° C or higher, more preferably -45 ° C or higher, so that it can be moderately heated to obtain practical strength. Spunbond non-woven fabric. In addition, the surface temperature of the heat roller is preferably -15 ° C or lower, and more preferably -20 ° C or lower, relative to the melting point of the polyolefin-based resin, so that excessive heat can be suppressed and used as a building material. Spunbond non-woven fabric can get moderate softness and processability.

The linear pressure of the heat embossing roller at the time of heat bonding is preferably 50 to 500 N / cm. By setting the linear pressure of the roll to preferably 50N / cm or more, more preferably 100N / cm or more, and even more preferably 150N / cm or more, it can be moderately heat-bonded to obtain a spunbond with practical strength. Not woven. On the other hand, by setting the linear pressure of the hot embossing roll to 500 N / cm or less, more preferably 400 N / cm or less, and even more preferably 300 N / cm or less, as a spunbond nonwoven fabric for building materials, Moderate softness and processability can be obtained.

Moreover, in the present invention, for the purpose of adjusting the thickness of the spunbond nonwoven fabric, before and / or after the heat bonding by the above-mentioned heat embossing roll, a hot calender composed of a pair of upper and lower flat rolls can be used. Roll and apply thermocompression bonding. The so-called upper and lower flat rollers are metal rollers or elastic rollers with no unevenness on the surface of the rollers. The metal rollers can be paired with the metal rollers, or the metal rollers can be used with the elastic rollers in pairs. The elastic roller referred to herein is a roller made of a material having more elasticity than a metal roller. Examples of the elastic roller include so-called paper rollers such as paper, cotton, and aromatic polyamide paper, or urethane resin, epoxy resin, silicon resin, polyester resin, and hard rubber, And resin rollers made of these mixtures.

The spunbond non-woven fabric of the present invention has high productivity, uniform texture, smooth surface and excellent softness, and also has high water resistance. Therefore, it can be suitably used as a building material, especially suitable for covering a house that requires moisture permeability and waterproofness. Not woven.

    [Example]    

Next, the spunbond nonwoven fabric of the present invention will be specifically described based on examples.

(1) Melt flow rate (MFR):

The melt flow rates of polyolefin resins and fibers were measured in accordance with ASTM D-1238 under conditions of a load of 2160 g and a temperature of 230 ° C.

(2) Average single fiber diameter (μm):

After being pulled and extended by the ejector, 10 small samples were randomly collected from the non-woven net captured on the net, and a surface photograph of 500 to 1000 times was taken with a microscope. The width of 100 fibers in total was used to calculate the average single fiber diameter (μm) from the average value.

(3) CV value of single fiber diameter (%)

From the standard deviation of the single fiber diameter obtained from the 100 fibers measured in the above (2) and the average single fiber diameter, the CV value of the single fiber diameter was calculated according to the following formula.

‧CV value of single fiber diameter (%) = standard deviation / mean × 100

(4) Spinning speed (m / min):

From the above average single fiber diameter and the solid density of the polyolefin-based resin used, the mass per 10,000 m of length is taken as the average single fiber fineness (dtex), and the second digit below the decimal point is rounded off and calculated. From the average single-fiber fineness and the resin discharge amount (hereinafter, referred to as the single-hole discharge amount) (g / min) discharged from the single hole of the spinneret set under each condition, the spinning speed was calculated according to the following formula.

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

(5) Dynamic friction coefficient of spunbond non-woven fibers with each other:

The friction coefficient of the fibers constituting the spunbond nonwoven fabric was measured in accordance with JIS L1015: 2010. Fibers were collected from the spunbond non-woven fabric and wound on a cylinder with an outer diameter of 8 mm from a Roeder friction coefficient tester. The fiber was wound parallel to the axis of the cylinder. The loader hangs in the center of the cylindrical bar and connects one end to the torsion-balanced hook. The cylindrical bar was rotated at a peripheral speed of 90 cm / min to obtain a load balanced by both ends of the fiber by torsional balance, and the kinetic friction coefficient was calculated by the following formula. The fibers collected from three different arbitrary locations were measured, and the average was taken as the coefficient of dynamic friction.

‧Coefficient of Dynamic Friction (μd) = 0.733log (W / (W-m))

Here,

W: load applied to both ends of the fiber

m: Torque balance reading.

(6) Unit area weight of spunbond nonwoven fabric:

The weight per unit area of the spunbond non-woven fabric is based on JIS L1913 (2010) 6.2 "mass per unit area". Three pieces of 20cm × 25cm test pieces are collected per 1m of the sample width, and each of them is measured under standard conditions. mass (g), the mean of which represents the mass per 1m ² (g / m ^2).

(7) Apparent density of spunbond nonwoven fabric:

The thickness of the spunbond non-woven fabric (mm) is based on JIS L1906 (2000 version) 5.1, using a pressure head with a diameter of 10 mm, at a thickness of 10 points per 1 m in the width direction of the non-woven fabric at a load of 10 kPa, at 0.01 The unit is mm, and the average value is rounded to the third decimal place.

Next, the apparent density (g / cm ³ ) of the spunbond nonwoven fabric was calculated from the weight and thickness per unit area before the rounding according to the following formula, and the third place below the decimal point was rounded.

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

(8) Water pressure resistance per unit area of spunbond nonwoven fabric:

The water pressure resistance of the spunbond nonwoven fabric was measured in accordance with "7.1.1A method (low water pressure method)" of JIS L1092: 2009. Collect 5 test pieces with a width of 150mm × 150mm at regular intervals in the width direction of the spunbond non-woven fabric, and use the Swiss FXEST FX-3000-IV hydrostatic tester "Hydro Tester" to fix the test pieces to the fixture (water test The contact area of the sheet is 100cm ² ), the water level is set at a speed of 600mm / min ± 30mm / min, the water level is increased, and the water penetrates the test piece. Water level when water drops. This measurement was performed on five test pieces, and the average value was regarded as the water pressure resistance (mmH ₂ O). The water pressure resistance thus obtained is divided by the weight per unit area before rounding according to the following formula, and the second place below the decimal point is rounded to obtain the water pressure per unit area weight (mmH ₂ O / (g / m ² )).

‧Water pressure resistance per unit area weight (mmH ₂ O / (g / m ² )) = [Water pressure resistance (mmH ₂ O)] / [Unit area weight (g / m ² )]

(9) The maximum and average pore sizes of spunbond nonwovens:

The maximum pore diameter and average pore diameter were evaluated using a porous material automatic pore measurement system "Capillary Flow Porometer CPF-1500AEXLC" in accordance with JIS K3832 (bubble point method). The diameter of the measurement sample was set to 25 mm, and Galwick (surface tension: 16 mN / m) was used as a measurement liquid with a known surface tension to perform a pore size distribution measurement. The maximum pore diameter was calculated from the pressure (bubble point) when air pressure was observed on the nonwoven fabric completely impregnated with the measurement solution. The average pore diameter was calculated from the measured pore diameter distribution. The measurement is a value obtained by sampling an arbitrary five points of a sample, rounding the second digit below the decimal point and using the first digit below the decimal point.

(10) Softness (formability) of non-woven fabric:

As a sensory evaluation of the touch of the nonwoven fabric, the softness was scored using the following criteria. This score was scored by 10 people, and the average was regarded as a non-woven touch evaluation. The higher the number of points is, the more excellent the flexibility is. It is judged that the workability in various processes is good, and 4.0 points or more are considered acceptable.

<Flexibility (formability)>

‧5 points: soft (good formability)

‧ 4 o'clock: Between 5 and 3 o'clock

‧3 points: Normal

‧ 2 o'clock: Between 3 o'clock and 1 o'clock

‧1 point: Hard (poor moldability)

    [Example 1]    

A polypropylene resin composed of a homopolymer having a melt flow rate (MFR) of 200 g / 10 minutes was melted in an extruder. For those having a spinning temperature of 235 ° C, a hole diameter of 0.30 mm, and a hole depth of 2 mm, Rectangular spinneret, spinning with a single hole with an output of 0.32g / min, cooling and solidifying by spraying cold air with a speed deviation of 13%, using a rectangular ejector, by setting the pressure of the ejector to Compressed air of 0.35 MPa is used for traction and extension. At the ejector outlet, flat plates with a width of 2 cm and a length of 10 cm are arranged alternately in a comb-tooth shape, and are inclined at an upstream side of the sheet by 10 to 30 °. The fiber opening device of a flat plate with a width of 2cm and a length of 10cm makes the sliver along the flat plate, disperses and opens the fiber in the sheet flow direction, and captures it on a moving mesh to obtain a polypropylene long fiber. Nonwoven web. The characteristics of the obtained polypropylene long fibers were that the average single fiber diameter was 10.1 μm, and the spinning speed converted therefrom was 4400 m / min. Regarding spinnability, no breaks were seen during spinning for 1 hour, which was good.

Next, an upper embossing roller made of metal and embossed with a waterdrop pattern was used, followed by an embossing roller with an area ratio of 16%, and an upper and lower pair of hot embossing rollers made of a metal flat roller was used for the lower roller. The resulting nonwoven web was thermally bonded at a temperature of 300 N / cm and a thermal bonding temperature of 130 ° C. to obtain a spunbonded nonwoven fabric having a basis weight of 30 g / m ² . The obtained spunbond nonwoven fabric was evaluated for thickness, apparent density, maximum pore diameter, average pore diameter, dynamic friction coefficient of fibers, MFR of fibers, and water pressure resistance per unit area weight. The results are shown in Table 1.

    [Example 2]    

A nonwoven fabric made of polypropylene long fibers was obtained in the same manner as in Example 1 except that the discharge amount per hole was set to 0.21 g / min and the pressure of the ejector was set to 0.50 MPa. The characteristics of the obtained spunbond long fibers were that the average single fiber diameter was 7.2 μm, and the spinning speed converted therefrom was 5700 m / min. Regarding spinnability, no breaks were seen during spinning for 1 hour, which was good. The results are shown in Table 1.

    [Example 3]    

A nonwoven fabric made of polypropylene long fibers was obtained in the same manner as in Example 1 except that the ejector pressure was set to 0.50 MPa. The characteristic of the obtained spunbond long fiber was that the average single fiber diameter was 8.9 μm, and the spinning speed converted therefrom was 5,600 m / min. Regarding spinnability, no breaks were seen during spinning for 1 hour, which was good. The results are shown in Table 1.

    [Example 4]    

A spun-bonded nonwoven fabric was obtained in the same manner as in Example 1, except that 1.0% by mass of ethylidenebisstearate was added to a polypropylene resin composed of a homopolymer as a fatty acid amide compound. The results are shown in Table 1.

    [Example 5]    

A spun-bonded nonwoven fabric was obtained in the same manner as in Example 2 except that 1.0% by mass of ethylidenebisstearate was added to a polypropylene resin composed of a homopolymer as a fatty acid amide compound. The results are shown in Table 1.

    [Example 6]    

A spun-bonded nonwoven fabric was obtained in the same manner as in Example 3, except that 1.0% by mass of ethylidenebisstearate was added to a polypropylene resin composed of a homopolymer as a fatty acid amide compound. The results are shown in Table 2.

    [Example 7]    

Except for a polypropylene resin composed of a homopolymer having an MFR of 60 g / 10 min, 1.0% by mass of ethynylstearate was used as the fatty acid amide compound, and the pressure of the ejector was set to 0.20 MPa. By the same method as in Example 1, a spunbond nonwoven fabric composed of polypropylene long fibers was obtained. The characteristic of the obtained spunbond long fiber was that the average single fiber diameter was 11.8 μm, and the spinning speed converted therefrom was 3,200 m / min. Regarding spinnability, no breaks were seen during spinning for 1 hour, which was good. The results are shown in Table 2.

    [Comparative Example 1]    

A spun-bonded nonwoven fabric was obtained in the same manner as in Example 7 except that 1.0% by mass of ethylidenebisstearate was not added as the fatty acid amide compound. The results are shown in Table 2.

    [Comparative Example 2]    

A spunbonded nonwoven fabric was obtained in the same manner as in Comparative Example 1 except that a polypropylene resin composed of a homopolymer having an MFR of 35 g / 10 min was used and the pressure of the ejector was set to 0.15 MPa. The results are shown in Table 2.

The spunbond nonwoven fabrics of Examples 1 to 7 have an average single fiber diameter of 6.5 to 11.9 μm, and the single fiber CV is small and uniform. The average pore diameter of the nonwoven surface is 0.1 to 25 μm, and the maximum pore diameter is 50 μm or less. The area weight has a water pressure resistance of 7 mmH ₂ O / (g / m ² ) or more, exhibits excellent water resistance, and is excellent in flexibility and formability. In particular, the fibers of Examples 4 to 6 in which the bisethyl stearate was added had a small coefficient of friction with each other, and could impart a moderate sliding property during the capture of the fiber web. Since the average pore surface of the nonwoven fabric was 0.1 to 25 μm, and the maximum pore diameter is 50 μm or less, so it has excellent water pressure resistance per unit area weight, and is suitable for non-woven fabrics such as non-woven fabrics for house covering materials that require moisture permeability and water resistance.

On the other hand, in Comparative Examples 1 and 2, since the average pore diameter on the surface of the nonwoven fabric was larger than 25 μm and the maximum pore diameter was larger than 50 μm, the water resistance characteristics were poor.

Although the present invention has been described in detail using specific aspects, various changes and modifications are possible without departing from the intention and scope of the present invention, which can be clearly understood by those skilled in the art. This application is based on the Japanese invention patent application filed on November 1, 2017 (Japanese Patent Application No. 2017-211607) and the Japanese invention patent application filed on July 27, 2018 (Japanese Patent Application No. 2018-141052). The contents are incorporated herein by reference.

Claims (7)

One kind of spunbond non-woven, spunbond which based polyolefin fibers constituting the nonwoven fabric, the average pore size of the nonwoven fabric surface is 0.1 ~ 25μm, and a maximum pore size of 50μm or less, and the water pressure resistance of the weight per unit area of 7mmH ₂ O / ( g / m ² ) or more.     For example, the spunbond non-woven fabric of claim 1, wherein the fiber constituting the non-woven fabric has a diameter of 6.5 to 11.9 μm.         For example, the spunbond nonwoven fabric of claim 1 or 2, wherein the dynamic friction coefficient of the fibers constituting the nonwoven fabric is 0.01 to 0.3.         For example, the spunbond nonwoven fabric according to any one of claims 1 to 3, wherein the MFR of the fibers constituting the nonwoven fabric is 155 to 850 g / 10 minutes.         The spunbond nonwoven fabric according to any one of claims 1 to 4, wherein the fibers constituting the nonwoven fabric contain a fatty acid ammonium compound having a carbon number of 23 to 50.         For example, the spunbond non-woven fabric of claim 5, wherein the fatty acid ammonium compound is added in an amount of 0.01 to 5.0 wt%.         The spunbond non-woven fabric according to claim 5 or 6, wherein the fatty acid ammonium compound is ammonium distearate.