WO2023058516A1 - Multilayer nonwoven fabric, method for producing same, and protective garment - Google Patents

Abstract

Provided are a multilayer nonwoven fabric having both high water resistance and antistatic properties despite no films being layered therein, a method for producing the multilayer nonwoven fabric, and a protective garment using the multilayer nonwoven fabric. One surface of the multilayer nonwoven fabric is formed from fibers comprising a polyolefin resin and has a spunbond nonwoven fabric layer A1 containing at least a phosphate ester arranged thereon, the other surface has arranged thereon a spunbond nonwoven fabric layer A2 formed from fibers comprising a polyolefin resin, and a meltblown nonwoven fabric layer B formed from at least one layer of fibers comprising a polyolefin resin is arranged between the spunbond nonwoven fabric layer A1 and the spunbond nonwoven fabric layer A2. The ratio (tA1/tA2) of the thickness (tA1) of the spunbond nonwoven fabric layer A1 to the thickness (tA2) of the spunbond nonwoven fabric layer A2 in a non-fused section of the multilayer nonwoven fabric is 1.5-3.0.

Description

LAMINATED NONWOVEN FABRIC AND MANUFACTURING METHOD THEREOF AND PROTECTIVE CLOTHING

The present invention relates to a laminated nonwoven fabric, and particularly to a laminated nonwoven fabric that is composed of fibers made of polyolefin resin, has excellent water resistance and antistatic properties, and has excellent productivity as a protective clothing application.

In recent years, non-woven fabrics have been used for various purposes, such as industrial materials, civil engineering materials, construction materials, living materials, agricultural materials, sanitary materials, and medical materials.

Especially, due to the decontamination work of radioactive substances and the global epidemic of infectious diseases, its use for protective clothing is attracting attention. Non-woven fabrics used in protective clothing must have both water resistance and dust protection performance to protect the wearer from chemical mist, dust, and aerosols that cause infectious diseases generated at manufacturing sites.

Conventionally, as a material used for such protective clothing, a protective clothing material has been proposed in which a polypropylene-based spunbond nonwoven fabric is laminated with a porous film (for example, see Patent Document 1).

In addition, antistatic properties are required for protective clothing for applications where it is necessary to suppress the generation of static electricity, which is the source of fire ignition, to prevent dust explosions. A laminated nonwoven fabric has been proposed in which a polypropylene-based spunbond nonwoven fabric coated with an antistatic agent and a meltblown nonwoven fabric are laminated together (see, for example, Patent Document 2).

JP 2016-102202 A WO2019/171995

A conventional protective clothing material, a laminate of non-woven fabric and porous film, can maintain water resistance due to the film, but it has poor breathability, and the inside of the clothing becomes stuffy when worn, making it impossible to work for a long time. In addition, a laminated nonwoven fabric made by laminating a polypropylene-based spunbond nonwoven fabric coated with an antistatic agent and a meltblown nonwoven fabric has breathability because it does not have a film, and although it improves the clumping inside the clothes when worn, the antistatic agent absorbs moisture in the air, liquefies, penetrates into the laminated nonwoven fabric, reaches the meltblown nonwoven fabric, and has a problem of lowering the water resistance. Therefore, the object of the present invention was made in view of the above circumstances, and the object is a laminated nonwoven fabric that has both high water resistance and antistatic properties without being laminated with a film, a method for producing the same, and It is to provide a protective clothing using this.

The inventors of the present invention have made intensive studies to achieve the above object, and found that a spunbonded nonwoven fabric layer composed of fibers made of a polyolefin resin and containing at least a phosphate ester is formed on one surface of the laminated nonwoven fabric. a spunbond nonwoven fabric layer on the other surface, and at least one melt-blown nonwoven fabric layer composed of fibers made of polyolefin resin disposed therebetween; It was found that by controlling the thickness ratio of the spunbond nonwoven fabric layers on both sides of the nonwoven fabric, both high water resistance and antistatic properties can be achieved.

The present invention has been completed based on these findings, and the following inventions are provided according to the present invention.

[1] A spunbond nonwoven fabric layer A1 made of fibers made of polyolefin resin and containing at least a phosphate ester is arranged on one surface,
A spunbond nonwoven fabric layer A2 made of fibers made of polyolefin resin is arranged on the other surface,
A laminated nonwoven fabric in which at least one melt-blown nonwoven fabric layer B composed of fibers made of a polyolefin resin is arranged between the spunbond nonwoven fabric layer A1 and the spunbond nonwoven fabric layer A2,
The ratio (t A1 /t A2 ) of the thickness (t _A1 ) of the spunbond nonwoven fabric layer A1 to the thickness ( _{t A2} ) of the spunbond nonwoven fabric layer A2 in the non-fused portion of the laminated nonwoven fabric is _1.5 or more. Laminated nonwoven fabric, which is 3.0 or less.

[2] The height _H1 of the non-fused portion on the one surface of the laminated nonwoven fabric is 50 μm or more and 200 μm or less, and the height _H1 of the height _H2 of the non-fused portion on the other surface of the laminated nonwoven fabric. The laminated nonwoven fabric according to [1], wherein the ratio (H ₂ /H ₁ ) is 1.1 or more and 4.0 or less.

[3] The laminated nonwoven fabric according to [1] or [2], wherein the spunbond nonwoven fabric layer A1 further contains silicone.

[4] The ratio (t _B /t) of the thickness (t _B ) of the melt blown nonwoven fabric layer B to the thickness (t) of the entire laminated nonwoven fabric is 0.05 or more and 0.15 or less [1] to The laminated nonwoven fabric according to any one of [3].

[5] A method for producing a laminated nonwoven fabric according to any one of [1] to [4],
forming a spunbond nonwoven layer, forming at least one meltblown nonwoven layer thereon, and further forming a spunbond nonwoven layer thereon to form a laminate;
a step of fusing the laminate using a thermal embossing roll, which is a combination of a roll having a smooth surface on one side and a roll having an engraved surface on the other side, to obtain a sheet;
A spunbond nonwoven fabric layer A1 is defined as the spunbond nonwoven fabric layer A1 on the side of the sheet that is in contact with the roll having a smooth roll surface, and a liquid containing at least a phosphate ester is applied to the surface of the spunbond nonwoven fabric layer A1. and
A method for producing a laminated nonwoven fabric, comprising:

[6] The method for producing a laminated nonwoven fabric according to [5], wherein the liquid further contains silicone.

[7] Protective clothing in which the laminated nonwoven fabric according to any one of [1] to [4] is used at least in the front body.

[8] Protective clothing, wherein 80% or more and 100% or less of the mass is the laminated nonwoven fabric according to any one of [1] to [4].

According to the present invention, it is possible to obtain a laminated nonwoven fabric composed of fibers made of polyolefin resin, excellent in water resistance and antistatic properties, suitable for use as protective clothing, a method for producing the same, and protective clothing obtained from the laminated nonwoven fabric.

FIG. 1 is a cross-sectional conceptual diagram illustrating one embodiment of the laminated nonwoven fabric of the present invention.

The laminated nonwoven fabric of the present invention comprises, on one surface, a spunbond nonwoven fabric layer A1 composed of fibers made of a polyolefin resin and containing at least a phosphate ester, and on the other surface, a polyolefin A spunbonded nonwoven fabric layer A2 composed of fibers made of a resin is disposed, and at least one layer of fibers made of a polyolefin resin is provided between the spunbonded nonwoven fabric layer A1 and the spunbonded nonwoven fabric layer A2. The spunbond nonwoven fabric having the thickness (t _A1 ) of the spunbond nonwoven fabric layer A1 in the non-fused portion of the laminated nonwoven fabric. The ratio (t _A1 /t _A2 ) to the thickness (t _A2 ) of layer A2 is 1.5 or more and 3.0 or less. The constituent elements will be described in detail below, but the present invention is not limited to the scope described below as long as it does not exceed the gist of the present invention.

[Polyolefin resin]
The spunbond nonwoven fabric layer A1, the spunbond nonwoven fabric layer A2, and the meltblown nonwoven fabric layer B according to the present invention are all made of fibers made of polyolefin resin. Here, the "polyolefin-based resin" in the present invention refers to a resin whose main repeating unit is an olefin unit. Similarly, "polyethylene-based resin" and "polypropylene-based resin" They refer to resins whose units are ethylene units and propylene units, respectively. Further, in the present invention, the polyolefin resin (P _A ) used for the fibers constituting the spunbond nonwoven fabric layer A1 and the fibers constituting the spunbond nonwoven fabric layer A2 is used for the fibers constituting the melt blown nonwoven fabric layer B. The polyolefin-based resin obtained is sometimes referred to as a polyolefin-based resin (P _B ).

Polyolefin-based resins include polyethylene-based resins, polypropylene-based resins, polybutene-based resins, and polymethylpentene-based resins. Polyethylene-based resins include ethylene homopolymers and copolymers of ethylene and various α-olefins, and polypropylene-based resins include propylene homopolymers or propylene and various α-olefins. A copolymer etc. are mentioned. Among them, polypropylene-based resins are preferably used from the viewpoint of spinnability and strength characteristics.

The proportion of propylene units in this polypropylene-based resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. By doing so, good spinnability can be maintained and strength can be improved.

The polyolefin resin (P _A ) preferably has a melt flow rate (sometimes abbreviated as MFR) of 75 g/10 min or more and 850 g/10 min or less. By setting the MFR to 75 g/10 minutes or more, more preferably 120 g/10 minutes or more, and even more preferably 155 g/10 minutes or more, the stress during drawing can be reduced, and even if drawing is performed at a high spinning speed, Stable spinning becomes possible. As a result, the fiber diameter of the spunbond nonwoven fabric layer is reduced, the surface is smoothed, and an antistatic agent such as a phosphate ester is uniformly applied to the surface, so that a laminated nonwoven fabric having good antistatic properties can be obtained. can be done. On the other hand, by setting the MFR to 850 g/10 minutes or less, more preferably 600 g/10 minutes or less, and even more preferably 400 g/10 minutes or less, the molecular weight of the polyolefin resin (P _A ) increases, and the Since the strength is increased, a laminated nonwoven fabric having sufficient strength to be used as protective clothing material can be obtained.

The polyolefin resin (P _B ) preferably has an MFR of 200 g/10 min or more and 2500 g/10 min or less. By setting the MFR to 200 g/10 minutes or more, more preferably 400 g/10 minutes or more, and even more preferably 600 g/10 minutes or more, the stress during drawing is reduced, so that the production capacity can be maintained and the fiber diameter can be reduced. A melt-blown nonwoven fabric layer can be obtained, and both productivity and water resistance can be achieved. On the other hand, by setting the MFR to 2,500 g/10 min or less, more preferably 2,000 g/10 min or less, and even more preferably 1,500 g/10 min or less, the back pressure of the die increases, and fluctuations in the resin discharge amount can be suppressed. Therefore, the melt-blown nonwoven fabric layer has a uniform fiber diameter, and a laminated nonwoven fabric with less variation in water pressure resistance can be obtained.

In addition, in the present invention, the value measured by ASTM D1238 (method A) is adopted for the MFR of the polyolefin resin. According to this standard, for example, polypropylene is measured under a load of 2.16 kg and a temperature of 230°C, and polyethylene is measured under a load of 2.16 kg and a temperature of 190°C.

The polyolefin-based resin used in the present invention may be a mixture of two or more types, and a resin composition containing other polyolefin-based resins, thermoplastic elastomers, and the like can also be used. Of course, two or more resins having different MFRs can be blended at any ratio to adjust the MFR of the polyolefin resin (P _A ) and/or the polyolefin resin (P _B ). In this case, the MFR of the resin to be blended with the main polyolefin resin is preferably 10 g/10 min or more and 1000 g/10 min or less, more preferably 20 g/10 min or more and 800 g/10 min or less, and further It is preferably 30 g/10 minutes or more and 600 g/10 minutes or less. By doing so, it is possible to prevent partial occurrence of viscosity unevenness in the blended polyolefin resin, uneven fineness, and deterioration of spinnability.

The polyolefin resin used in the present invention contains antioxidants, weathering agents, light stabilizers, antifogging agents, blocking agents, lubricants, nucleating agents, and pigments such as titanium oxide, as long as the effects of the present invention are not impaired. Additives such as, or other polymers can be added as necessary.

In addition, when spinning the fibers described later, in order to prevent the occurrence of partial viscosity unevenness, uniform the fineness of the fibers, and further reduce the fiber diameter as described later, the molecular weight of this resin is may be decreased to increase the MFR. As a method for increasing the MFR, for example, a method of heating the resin before use to thermally decompose it, a method of adding a peroxide and heat-treating the resin, and the like are conceivable.

The melting point of the polyolefin resin used in the present invention is preferably 80°C or higher and 200°C or lower. By setting the melting point to preferably 80° C. or higher, more preferably 100° C. or higher, and even more preferably 120° C. or higher, heat resistance that can withstand practical use can be easily obtained. In addition, by setting the melting point to preferably 200° C. or lower, more preferably 180° C. or lower, the yarn extruded from the spinneret can be easily cooled, thereby suppressing fusion between fibers and facilitating stable spinning.

[fiber]
The fibers made of the polyolefin resin (P _A ) constituting the spunbond nonwoven fabric layer A1 according to the present invention preferably have an average single fiber diameter of 10.0 μm or more and 14.0 μm or less. By setting the average single fiber diameter to preferably 10.0 μm or more, more preferably 12.0 μm or more, it is possible to suppress a decrease in water pressure resistance due to permeation of post-processing chemicals due to capillary action. On the other hand, by setting the average single fiber diameter to preferably 14.0 μm or less, more preferably 13.0 μm or less, the flexibility and uniformity are high, and even if the content ratio of the melt blown nonwoven fabric layer in the laminated nonwoven fabric is low, it is practical. A laminated nonwoven fabric having excellent durable water resistance can be obtained.

The fibers made of the polyolefin resin (P _A ) constituting the spunbond nonwoven fabric layer A2 according to the present invention preferably have an average single fiber diameter of 6.5 μm or more and 10.0 μm or less. 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, a decrease in spinnability is prevented and a nonwoven fabric layer having a stable average single fiber diameter is obtained. can be formed. On the other hand, by setting the average single fiber diameter to preferably 10.0 μm or less, more preferably 9.0 μm or less, the flexibility and uniformity are high, and even if the content ratio of the melt blown nonwoven fabric layer in the laminated nonwoven fabric is low, it is practical. A laminated nonwoven fabric having excellent durable water resistance can be obtained.

The average single fiber diameter (μm) of the fibers made of the polyolefin resin (P _A ) constituting the spunbond nonwoven fabric layers A1 and A2 according to the present invention is calculated by the following procedure. For the measurement, for example, a scanning electron microscope "VHX-D500" manufactured by Keyence Corporation can be used. Henceforth, unless otherwise specified, this device can be used as a scanning electron microscope (SEM) shown in the description of the measurement method.
(1) Collect 10 small piece samples at random from the laminated nonwoven fabric.
(2) Take a photograph of the surface with an SEM at a magnification of 500 to 1000, and measure the width of 100 polyolefin fibers in total, 10 from each sample.
(3) Calculate the average single fiber diameter (μm) from the average value of the 100 measured values.

On the other hand, the fibers made of the polyolefin resin (P _B ) constituting the melt blown nonwoven fabric layer B according to the present invention preferably have an average single fiber diameter of 0.1 μm or more and 8.0 μm or less. By setting the average single fiber diameter of the fibers made of the polyolefin resin (P _B ) to preferably 0.1 μm or more, more preferably 0.4 μm or more, the fibers are easily collected when forming the melt blown nonwoven fabric layer. It is possible to suppress scattering to the surroundings and to obtain a more uniform laminated nonwoven fabric. On the other hand, by setting the average fiber diameter to preferably 8.0 μm or less, more preferably 7.0 μm or less, the barrier properties of the melt blown nonwoven fabric layer B can be improved, and the water pressure resistance of the laminated nonwoven fabric can be improved.

The average single fiber diameter (μm) of the fibers composed of the polyolefin resin (P _B ) constituting the melt blown nonwoven fabric layer B according to the present invention is calculated by the following procedure.
(1) Collect 10 small piece samples at random from the laminated nonwoven fabric.
(2) The sampled specimen is cut with a freezing microtome, the obtained cross section is subjected to a conductive treatment, and the cross section is photographed with an SEM at a magnification of 4000 to 10000 times.
(3) The width of 100 fibers in total, 10 fibers from the melt-blown nonwoven fabric layer B of each sample, is measured.
(4) Calculate the average single fiber diameter (μm) from the average value of the 100 measured values.

[Laminated nonwoven fabric]
The laminated nonwoven fabric of the present invention comprises, on one surface, a spunbond nonwoven fabric layer A1 composed of fibers made of a polyolefin resin and containing at least a phosphate ester, and on the other surface, a polyolefin A spunbonded nonwoven fabric layer A2 composed of fibers made of a resin is disposed, and at least one layer of fibers made of a polyolefin resin is provided between the spunbonded nonwoven fabric layer A1 and the spunbonded nonwoven fabric layer A2. A melt-blown nonwoven fabric layer B composed of is arranged. By configuring in this way, it is possible to impart water resistance and antistatic properties at or above the levels required for nonwoven fabrics for chemical protective clothing.

Furthermore, the configuration of the laminated nonwoven fabric of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional conceptual diagram illustrating one embodiment of the laminated nonwoven fabric of the present invention. In FIG. 1, a spunbond nonwoven fabric layer A1 (12) is arranged on one surface of a laminated nonwoven fabric (11), and a spunbond nonwoven fabric layer A2 (14) is arranged on the other surface. A laminated nonwoven fabric (11) in which one meltblown nonwoven fabric layer B (13) is arranged between the bonded nonwoven fabric layer A1 (12) and the spunbond nonwoven fabric layer A2 (14) is exemplified. The fusion-bonded portion (15) is a region where the fibers constituting the spunbond nonwoven fabric layer A1 (12), the spunbond nonwoven fabric layer A2 (14), and the melt blown nonwoven fabric layer B (13) in the laminated nonwoven fabric are melted. The portion other than this is defined as the non-fused portion (16) in the present invention. The spunbond nonwoven fabric layer A1 (12) and the spunbond nonwoven fabric layer A2 (14) are distinguished by measuring the respective thicknesses (t _A1 , t _A2 ) in the non-fused portion (16) by the method described later, A spunbond nonwoven fabric layer having a greater thickness is used as the spunbond nonwoven fabric layer A1 (12).

The spunbond nonwoven fabric layer A1 according to the present invention contains at least a phosphate ester. Here, in the present invention, the expression that the spunbond nonwoven fabric layer "contains a phosphate ester" means that the fibers constituting the spunbond nonwoven fabric layer contain the phosphate ester, or the spunbond nonwoven fabric layer is composed of It refers to the state in which a phosphate ester is applied to the surface of the fiber.

The state in which the fibers constituting the spunbond nonwoven fabric layer contain the phosphate ester includes, for example, the state in which the phosphate ester is kneaded into the polyolefin resin. In addition, the state in which the phosphate ester is applied to the surface of the fibers constituting the spunbond nonwoven fabric layer includes, for example, the state in which the phosphate ester is applied to the surface of the fibers, more specifically, the spunbond nonwoven fabric layer. Examples include a state in which 0.01% by mass or more and 2% by mass or less is provided with respect to the mass of the layer. From the viewpoint of production cost and antistatic properties, it is more preferable that the phosphate ester is applied to the surface of the fibers constituting the spunbond nonwoven fabric layer.

As the phosphate ester, for example, from the group consisting of (alcohol) and (a compound obtained by adding an alkylene oxide having 2 to 4 carbon atoms at a ratio of 1 to 10 mol with respect to 1 mol of alcohol) Phosphoric acid ester obtained by reacting at least one selected with (phosphorus pentoxide or phosphorus oxyhalide), alkali metal salt of phosphoric acid ester, alkaline earth metal salt of phosphoric acid ester, phosphoric acid Amine salts of esters are mentioned. Among them, when the alcohol is an aliphatic linear alkyl alcohol having 6 to 22 carbon atoms or an aliphatic alkyl alcohol having a branched structure having 7 to 24 carbon atoms, the laminated nonwoven fabric having excellent antistatic properties It is more preferable because it can be

In the present invention, by using a phosphate ester, it is possible to impart antistatic performance to the laminated nonwoven fabric while maintaining the waterproof pressure resistance of the laminated nonwoven fabric. In general, the antistatic performance itself can be expressed by imparting some kind of hydrophilic substance to the laminated nonwoven fabric. However, it may liquefy and permeate into the laminated nonwoven fabric. Furthermore, if the liquid penetrates into the meltblown layer, which is a functional layer that exhibits barrier properties such as water pressure resistance, the water pressure resistance of the laminated nonwoven fabric may be greatly reduced. The present invention has found that by using this phosphate ester, it is possible to obtain a laminated nonwoven fabric having excellent water resistance while exhibiting a certain degree of hydrophilicity and exhibiting sufficient antistatic properties. .

The inclusion of a phosphate ester in the spunbond nonwoven layer of the laminated nonwoven fabric of the present invention can be confirmed by extraction tests, elemental analysis, energy dispersive X-ray analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy (FT-IR). ), etc., or by using them in combination. For example, in the FT-IR spectrum of the laminated nonwoven fabric obtained by total reflection measurement, when a peak derived from the P—O—C bond of the phosphate ester is detected at 950 to 1060 cm ⁻¹ , the spunbond nonwoven fabric on the surface It is determined that the layer contains a phosphate ester.

In addition, as a specific laminated structure of the laminated nonwoven fabric of the present invention, for example, from the surface of the spunbond nonwoven fabric layer A1 side, (spunbond nonwoven fabric layer A1) / (meltblown nonwoven fabric layer B) / (spunbond nonwoven fabric layer A2) ), SMS nonwoven fabric laminated with (spunbond nonwoven fabric layer A1) / (meltblown nonwoven fabric layer B) / (meltblown nonwoven fabric layer B) / (spunbond nonwoven fabric layer A2), (spunbond nonwoven fabric Layer A1)/(spunbond nonwoven layer A1)/(meltblown nonwoven layer B)/(meltblown nonwoven layer B)/(spunbond nonwoven layer A2), or (spunbond nonwoven layer A1)/(meltblown nonwoven layer B) /(meltblown nonwoven fabric layer B)/(spunbond nonwoven fabric layer A2)/(spunbond nonwoven fabric layer A2) laminated SSMMS nonwoven fabric.

In the laminated nonwoven fabric of the present invention, the spunbond nonwoven fabric layer A1 preferably further contains silicone. By doing so, the silicone exhibits appropriate water repellency, suppresses the decrease in water pressure resistance due to the addition of the phosphate ester that exhibits antistatic performance, and makes it easier to achieve both antistatic performance and high water pressure resistance. can be

Here, in the present invention, the expression that the spunbond nonwoven fabric layer A1 "contains silicone" means that the fibers that constitute the spunbond nonwoven fabric layer A1 contain silicone, or that the fibers that constitute the spunbond nonwoven fabric layer A1 contain silicone. It refers to a state in which silicone is applied to the surface of Further, the term "silicone" as used in the present invention refers to a synthetic polymer compound having a main skeleton formed by siloxane bonds.

A state in which silicone is contained in the fibers constituting the spunbond nonwoven fabric layer A1 includes a state in which silicone is kneaded into a polyolefin resin. The state in which silicone is applied to the surfaces of the fibers constituting the spunbond nonwoven fabric layer A1 includes, for example, the state in which silicone is applied to the surfaces of the fibers, more specifically, the spunbond nonwoven fabric layer A1. A state in which 0.01% by mass or more and 2% by mass or less is added to the mass can be mentioned.

Examples of silicone include amino-modified silicone oil, epoxy-modified silicone oil, carbonyl-modified silicone oil, carbinol-modified silicone oil, polyether-modified silicone oil, amino/alkoxy-modified silicone oil, epoxy/polyether-modified silicone oil, amino/ Polyether-modified silicone oil, dimethylsilicone oil, phenylsilicone oil and the like can be mentioned.

The presence of silicone in the spunbond nonwoven fabric layer A1 of the laminated nonwoven fabric of the present invention can be analyzed by an extraction test, elemental analysis, energy dispersive X-ray analysis, FT-IR, etc., or a combination thereof. For example, the surface of a test piece taken from a laminated nonwoven fabric is analyzed with an energy dispersive X-ray device, and in the fluorescent X-ray spectrum obtained, when a signal derived from silicon is detected, the spunbond nonwoven fabric layer on the surface Determined to contain silicone.

In the laminated nonwoven fabric of the present invention, the ratio (t _A1 /t _A2 ) of the spunbond nonwoven fabric layer A1 (t _A1 ) in the non-fused portion to the thickness (t _A2 ) of the spunbond nonwoven fabric layer A2 is 1.5 or more3. 0 or less. By setting the thickness ratio t _A1 /t _A2 to preferably 1.7 or more, it is possible to suppress a decrease in water pressure resistance due to permeation of an antistatic agent such as a phosphate ester. On the other hand, by setting the thickness ratio t _A1 /t _A2 to 3.0 or less, it is possible to suppress the occurrence of wrinkles due to shrinkage when providing the fused portion.

The thickness ratio of the spunbond nonwoven fabric layer in the laminated nonwoven fabric of the present invention is measured as follows.
(1) A test piece having a width of 20 mm×20 mm is taken from the laminated nonwoven fabric.
(2) The sampled test piece is cut with a freezing microtome, the obtained cross section is subjected to a conductive treatment, and the cross section is photographed with an SEM at a magnification of 300 times. If the SEM photograph of the cross section includes the fused portion, the observation field of view is moved and the photograph is taken again.
(3) From the SEM photograph of the cross section, for each of the spunbond nonwoven fabric layers A1 and A2, the distance from the surface of the spunbond nonwoven fabric layer to the interface of the meltblown nonwoven fabric layer was measured at 5 points, and each average value was t _A1 and t _A2 . and
(4) Divide t _A1 by t _A2 and round off to the second decimal place to calculate the thickness ratio t _A1 /t _A2 .

The thickness ratio (t _A1 /t _A2 ) can be controlled by adjusting the basis weight and fiber diameter of each spunbond nonwoven fabric layer.

In the laminated nonwoven fabric of the present invention, the height _H1 of the non-fused portion on the surface on which the spunbond nonwoven fabric layer A1 is arranged is 50 μm or more and 200 μm or less, and the height _H2 of the non-fused portion on the other surface is The ratio (H ₂ /H ₁ ) to H 1 is preferably 1.1 or more and 4.0 or _less .

By setting the height _H1 to preferably 50 μm or more, the laminated nonwoven fabric becomes flexible, and comfort when used as a protective clothing and storability when the protective clothing is folded can be improved. . On the other hand, _H1 is preferably 200 μm or less, more preferably 180 μm or less, still more preferably 150 μm or less, and particularly preferably 120 μm or less, so that the surface is smooth and antistatic agents such as phosphate esters are uniformly applied. It is applied to the surface and has good antistatic properties.

The height ratio (H ₂ /H ₁ ) is preferably 1.1 or more, more preferably 1.5 or more, so that the laminated nonwoven fabric becomes soft, and when used as protective clothing It is possible to improve the comfort of wearing and the storability when folding the protective clothing. By setting H ₂ /H ₁ to preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less, deformation of the melt blown nonwoven fabric layer can be suppressed and water pressure resistance is improved. be able to.

The height H ₂ of the non-fused portion on the other surface is preferably 200 μm or more and 400 μm or less as long as the range of the height ratio (H ₂ /H ₁ ) is satisfied. When the thickness is preferably 200 μm or more, the laminated nonwoven fabric becomes soft, and comfort when used as protective clothing and storability when the protective clothing is folded can be improved. On the other hand, when the thickness is preferably 400 μm or less, more preferably 370 μm or less, and even more preferably 350 μm or less, deformation of the melt blown nonwoven fabric layer can be suppressed and water pressure resistance can be improved.

In the laminated nonwoven fabric of the present invention, the heights H ₁ and H ₂ of the non-fused portions will be explained using the example of the conceptual cross-sectional view of FIG. 1 . Height difference H between the highest point of the non-fused portion and the lowest point of the fused portion on one surface (the surface on the side of the spunbond nonwoven fabric layer A1 (12)) in the cross section of the laminated nonwoven fabric (11) ₁ is the height _H1 of the unfused portion, and the highest point of the unfused portion and the lowest point of the fused portion on the other surface (the surface on the side of the spunbond nonwoven fabric layer A2 (14)); is the height _{H2 of} the unfused portion.

The heights H ₁ and _H 2 of the non-fused portions in the laminated nonwoven fabric of the present invention and the ratio of H ₂ to H ₁ (H ₂ /H ₁ ) are measured as follows.
(1) A test piece having a width of 20 mm×20 mm is taken from the laminated nonwoven fabric.
(2) The sampled test piece is cut with a freezing microtome so as to include the non-fused portion, the obtained cross section is subjected to a conductive treatment, and the cross section is photographed using an SEM.
(3) From the cross-sectional SEM photograph, for each of the spunbond nonwoven fabric layers A1 and A2, between the tangent line passing through the lowest point of the fused part and the tangent line passing through the highest point of the surface of the spunbond nonwoven fabric layer in the non-fused part The distance (μm) is measured at 5 points, and the values obtained by rounding each average value (μm) to the first decimal place are defined as H ₁ (μm) and H ₂ (μm).
(4) Divide _H2 by _H1 and round off to the second decimal place to calculate the height ratio ( _H2 / _H1 ).

The method of adjusting the height of the non-fused portion of the laminated nonwoven fabric is possible by adjusting the basis weight and fiber diameter of the spunbond nonwoven fabric layer. It is also possible by adjusting the engraving shape of the calender roll used in the later-described fusing step.

The ratio (t _B /t) of the thickness (t _B ) of the melt-blown nonwoven fabric layer B of the laminated nonwoven fabric of the present invention to the thickness (t) of the entire laminated nonwoven fabric is preferably 0.05 or more and 0.15 or less. Water resistance can be improved by setting t _B /t to preferably 0.05 or more, more preferably 0.08 or more. Here, the thickness of the entire laminated nonwoven fabric is the distance from the highest point on the surface of the spunbond nonwoven fabric layer A1 in the non-fused portion to the highest point on the surface of the spunbond nonwoven fabric layer A2 in the cross section of the laminated nonwoven fabric. say about

On the other hand, by setting t _B /t to preferably 0.15 or less, more preferably 0.12 or less, sufficient strength for use as protective clothing can be obtained.

The ratio (t _B /t) of the thickness (t B ) of the melt blown nonwoven fabric layer B in the laminated nonwoven fabric of the present invention to the thickness (t) of the entire laminated nonwoven fabric (t _B /t) is measured as follows.
(1) A test piece having a width of 20 mm×20 mm is taken from the laminated nonwoven fabric.
(2) The sampled test piece is cut with a freezing microtome, the obtained cross section is subjected to a conductive treatment, and the cross section is photographed with an SEM at a magnification of 300 times. If the SEM photograph of the cross section includes the fused portion, the observation field of view is moved and the photograph is taken again.
(3) From the SEM photograph of the cross section, the distance from the interface between the spunbond nonwoven fabric layer A1 and the meltblown nonwoven fabric layer B to the interface between the spunbond nonwoven fabric layer A2 and the meltblown nonwoven fabric layer B is measured at five points, and the average value is calculated. The thickness of the melt-blown nonwoven fabric layer B is defined as (t _B ).
(4) From the cross-sectional SEM photograph, measure the distance from the surface of the spunbond nonwoven fabric layer A1 to the surface of the spunbond nonwoven fabric layer A2 at five points, and take the average value as the thickness (t) of the entire laminated nonwoven fabric.
(5) Divide _tB by t and round off to the third decimal place to obtain the thickness ratio ( _tB /t).

t _B /t can be adjusted by adjusting the basis weight of the melt blown nonwoven fabric layer B and the average single fiber diameter. It is also possible by adjusting the bonding temperature, linear pressure and clearance in the fusion bonding process.

The basis weight of the laminated nonwoven fabric of the present invention is preferably 40 g/m ² or more and 100 g/m ² or less. By setting the basis weight to preferably 40 g/m ² or more, more preferably 50 g/m ² or more, it is possible to obtain a laminated nonwoven fabric having practical water pressure resistance and mechanical strength.

On the other hand, by setting the basis weight to preferably 100 g/m ² or less, more preferably 70 g/m ² or less, it is possible to obtain a laminated nonwoven fabric that does not hinder the wearer's workability when used as protective clothing. In addition, it is possible to reduce the thickness of the protective clothing when it is folded, and it is possible to reduce the storage space for stockpile items.

The basis weight of the laminated nonwoven fabric of the present invention is measured by the following procedure according to JIS L1913:2010 "General nonwoven fabric test method", "6.2 Mass per unit area".
(1) Three test pieces of 20 cm x 25 cm are collected per 1 m width of the sample.
(2) Weigh each mass (g) in the standard state.
(3) The average value is represented by mass (g/m ² ) per 1 m ² .

The laminated nonwoven fabric of the present invention preferably has a water pressure resistance per unit basis weight of 15 mmH ₂ O/(g/m ² ) or more. By setting the water pressure resistance per unit basis weight to 15 mmH ₂ O/(g/m ² ) or more, and more preferably 17 mmH ₂ O/(g/m ² ) or more, the flexibility is maintained while maintaining practical water resistance. A laminated nonwoven fabric having excellent properties can be obtained. There is no particular upper limit to the water pressure resistance, but since the nonwoven fabric structure that exhibits high water pressure resistance has a dense structure, the air permeability of the laminated nonwoven fabric decreases and it gets stuffy when wearing protective clothing. The upper limit of water pressure is preferably 30 mmH ₂ O/(g/m ² ).

In addition, the water pressure resistance per unit basis weight of the laminated nonwoven fabric of the present invention is according to JIS L1092: 2009 "Waterproof test method for textile products""7.1.1 A method (low water pressure method)" according to the following procedure. measured by
(1) Five test pieces each having a width of 150 mm×150 mm are taken from the laminated nonwoven fabric.
(2) The test piece is set in the clamp of the measuring device (the part of the test piece that comes into contact with water has a size of 100 cm ² ).
(3) Raise the level device filled with water at a speed of 600 mm/min±30 mm/min, and measure the water level in mm units when water comes out from three places on the back side of the test piece.
(4) Perform the above measurements on five test pieces, and calculate the average value.
(5) Divide the calculated ventilation amount (mmH ₂ O) by the basis weight (g/m ² ) measured by the above method.

The air permeability per unit basis weight of the laminated nonwoven fabric of the present invention is 0.01 (cm ³ /(cm ² ·sec))/(g/m ² ) or more and 5 (cm ³ /(cm ² ·sec))/( g/m ² ) or less. The permeation amount per unit basis weight is preferably 2 (cm ³ /(cm ² ·sec))/(g/m ² ) or less, more preferably 1 (cm ³ /(cm ² ·sec))/(g/ m ² ) or less, and more preferably 0.5 (cm ³ /(cm ² ·sec))/(g/m ² ) or less, to maintain the water resistance required for protective clothing and the like. can be done. On the other hand, the air permeability per unit basis weight is preferably 0.02 (cm ³ /(cm ² ·sec)) / (g/m ² ) or more, more preferably 0.04 (cm ³ /(cm ² ·sec) ))/(g/m ² ) or more, more preferably 0.06 (cm ³ /(cm ² ·sec))/(g/m ² ) or more, when worn for protective clothing etc. It can reduce steam. The air permeability can be adjusted by the basis weight, average single fiber diameter, basis weight of the melt-blown nonwoven fabric layer B, thermocompression bonding conditions (compression rate, temperature and linear pressure), and the like.

The permeation amount per unit basis weight of the laminated nonwoven fabric of the present invention is measured according to JIS L1913:2010 "General nonwoven fabric test methods", "6.8.1 Frazier method", by the following procedure.
(1) Cut out a test piece of 80 cm×100 cm from the laminated nonwoven fabric.
(2) Measure at arbitrary 20 points on the test piece at a barometer pressure of 125 Pa.
(3) Calculate the average value of the above 20 points by rounding off to the second decimal place.
(4) Divide the calculated permeation rate (cm ³ /(cm ² ·sec)) by the basis weight (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 method for producing a laminated nonwoven fabric of the present invention preferably comprises forming a spunbond nonwoven fabric layer, forming at least one meltblown nonwoven fabric layer thereon, and further forming the spunbond nonwoven fabric layer thereon to form a laminate. and the laminate is fused using a hot embossing roll, which is a combination of a roll with a smooth surface on one side and a roll with an engraved surface on the other side. a step of obtaining a sheet (step 2), and a spunbond nonwoven fabric layer A1 on the side of the sheet with which the roll having a smooth roll surface abuts, and the spunbond nonwoven fabric layer A1 side of the sheet. a step of applying a liquid containing at least a phosphate ester to the surface (step 3).

(Step 1: Step of forming a spunbond nonwoven fabric layer, forming at least one meltblown nonwoven fabric layer thereon, and further forming the spunbond nonwoven fabric layer thereon to form a laminate)
In this step, the spunbond nonwoven fabric layer and the meltblown nonwoven fabric layer can be formed by a spunbond method and a meltblown method, respectively. As a method of forming a laminate by laminating these, for example, fibers formed by a meltblowing method are deposited directly on the initially formed spunbond nonwoven fabric layer to form a meltblown nonwoven fabric layer, and further, The resulting nonwoven layers are sequentially deposited with additional fibers to form a laminate, such as by depositing the fibers formed by the spunbond process to form a spunbond nonwoven layer, or formed separately. The spunbond nonwoven fabric layer and the melt blown nonwoven fabric layer are superimposed, and the nonwoven fabric layers are fused by heating and pressurizing, or bonded with an adhesive such as a hot melt adhesive or a solvent adhesive to form a laminate. can be adopted. From the viewpoint of productivity, a preferred embodiment is a method of sequentially depositing fibers on the obtained nonwoven fabric layer to form a laminate. In addition, the laminated structure is as described above.

A spunbond nonwoven fabric layer is formed by spinning a molten polyolefin resin from a spinneret as long fibers, cooling and stretching the fibers, and then collecting the fibers on a moving net. The drawing may be performed by sucking compressed air using an ejector or the like.

Various shapes such as round and rectangular can be adopted for the shape of the spinneret and ejector. In particular, the combination of a rectangular nozzle and a rectangular ejector is recommended because it uses a relatively small amount of compressed air and is excellent in terms of energy cost, and because the yarns are less likely to fuse or rub against each other, and the yarns can be easily opened. It is preferably used.

In the present invention, a polyolefin resin is melted in an extruder, weighed, supplied to a spinneret, and spun as long fibers. The spinning temperature at which the polyolefin resin is melted and spun is preferably 200°C or higher and 270°C or lower, more preferably 210°C or higher and 260°C or lower, and still more preferably 220°C or higher and 250°C or lower. By setting the spinning temperature within the above range, a stable molten state can be obtained and excellent spinning stability can be obtained.

The filament of the spun filament is cooled, and the cooling methods include, for example, a method of forcibly blowing cold air onto the filament, a method of natural cooling at the ambient temperature around the filament, and a spinneret and ejector. A method of adjusting the distance between them can be mentioned, or a method of combining these methods can be adopted. In addition, the cooling conditions can be appropriately adjusted in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the atmospheric temperature, and the like.

Next, the yarn that has been cooled and solidified may be pulled by compressed air jetted from the ejector and stretched. The spinning speed is preferably 3000 m/min or more and 6500 m/min or less, more preferably 3500 m/min or more and 6500 m/min or less, and still more preferably 4000 m/min or more and 6500 m/min or less. By setting the spinning speed to 3000 m/min or more and 6500 m/min or less, high productivity can be obtained, and the oriented crystallization of the fibers can be promoted to obtain high-strength long fibers.

Subsequently, the obtained filaments are collected on a moving net or on an already formed spunbond nonwoven layer or meltblown nonwoven layer placed on a moving net to form a nonwoven fabric layer. . In the present invention, it is also a preferred embodiment to temporarily bond these nonwoven fabric layers by contacting a hot flat roll from one side thereof on the net. By doing so, it is possible to prevent the surface layer of the nonwoven fabric layer from being turned up or blown away during transportation on the net, thereby preventing the texture from deteriorating, and improving the transportability from the collection of the yarn to the thermocompression bonding. can be improved.

Next, the meltblown nonwoven fabric layer can be formed by adopting a known manufacturing method. A polyolefin resin is melted in an extruder and supplied to the nozzle, and hot air is blown on the thread extruded from the nozzle to thin it, and then placed on a collection net or a moving net. A meltblown nonwoven fabric layer is formed on an already formed spunbond nonwoven fabric layer or a meltblown nonwoven fabric layer. The meltblowing method does not require complicated steps, can easily obtain fine fibers of several μm, and can exhibit high water resistance.

(Step 2: A step of fusing the laminate using a hot embossing roll, which is a combination of a roll with a smooth surface on one side and a roll with an engraved surface on the other side, to obtain a sheet)
In this step, a sheet is obtained by fusing using a hot embossing roll, which is a combination of a roll having a smooth surface on one side and a roll having an engraved surface on the other side. By doing so, the productivity is excellent, and the finally obtained laminated nonwoven fabric is given strength in the partially fused portions, and retains the texture and feel unique to spunbond nonwoven fabric in the non-fused portions. can do.

As for the surface material of the hot embossing roll, in order to obtain a sufficient thermocompression effect and to prevent the engraving (unevenness) of one embossing roll (engraving roll) from being transferred to the surface of the other roll, metal rolls and A preferred embodiment is pairing with a metal roll.

The embossing adhesion area ratio by the hot embossing roll is preferably 5% or more and 30% or less. By setting the bonding area to preferably 5% or more, more preferably 8% or more, and even more preferably 10% or more, it is possible to obtain strength that can be used practically as a laminated nonwoven fabric. On the other hand, by setting the adhesion area to preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less, it is possible to obtain appropriate flexibility in protective clothing and the like.

The embossed bonding area ratio here refers to the ratio of the area of the fused portion to the total area of the laminated nonwoven fabric. Specifically, in the case of heat-bonding with a roll having unevenness and a flat roll, it refers to the ratio of the portion (fused portion) where the convex portion of the roll having unevenness contacts the laminated nonwoven fabric to the entire laminated nonwoven fabric.

　Circular, elliptical, square, rectangular, parallelogram, rhombus, regular hexagon, regular octagon, etc. can be used as the shape of the bonded part by the heat embossing roll. Moreover, it is preferable that the bonded portions are uniformly present at regular intervals in the longitudinal direction (conveyance direction) and the width direction of the laminated nonwoven fabric. By doing so, variations in the strength of the laminated nonwoven fabric can be reduced.

It is a preferred embodiment that the surface temperature of the hot embossing roll during fusion is -50°C or higher and -15°C or lower with respect to the melting point of the polyolefin resin used. To obtain a laminated nonwoven fabric having a practically sufficient strength through moderate fusion by setting the surface temperature of a hot embossing roll to preferably −50° C. or higher, more preferably −45° C. or higher with respect to the melting point of a polyolefin resin. can be done. In addition, the surface temperature of the hot embossing roll is preferably −15° C. or less, and more preferably −20° C. or less, relative to the melting point of the polyolefin resin, thereby suppressing excessive fusion and making the laminated nonwoven fabric especially protective. Appropriate flexibility and workability suitable for use in clothes can be obtained.

The linear pressure of the hot embossing roll during fusion is preferably 50 N/cm or more and 500 N/cm or less. By setting the linear pressure of the hot embossing roll to preferably 50 N/cm or more, more preferably 100 N/cm or more, and even more preferably 150 N/cm or more, the laminated nonwoven fabric is appropriately fused and has a strength suitable for practical use. Obtainable. On the other hand, by setting the linear pressure of the heat embossing roll to preferably 500 N/cm or less, more preferably 400 N/cm or less, and even more preferably 300 N/cm or less, it can be used as a laminated nonwoven fabric, especially for protective clothing. Appropriate moderate flexibility and workability can be obtained.

In addition, in order to adjust the thickness of the laminated nonwoven fabric of the present invention, it is also possible to perform thermocompression bonding with a thermal calender roll consisting of a pair of upper and lower flat rolls before and/or after fusion bonding with the above-mentioned thermal embossing rolls. A pair of upper and lower flat rolls is a metal roll or elastic roll that does not have unevenness on the surface of the roll. can be used.

Also, the elastic roll here means a roll made of a material having elasticity compared to a metal roll. Examples of elastic rolls include so-called paper rolls such as paper, cotton and aramid paper, and resin rolls made of urethane-based resins, epoxy-based resins, silicone-based resins, polyester-based resins, hard rubbers, and mixtures thereof. be done.

(Step 3: A step of applying a liquid containing at least a phosphate ester to the surface of the spunbond nonwoven fabric layer A1, which is the spunbond nonwoven fabric layer A1 on the side of the sheet with which the roll surface is in contact).
In the present step, the spunbond nonwoven fabric layer A1 is the spunbond nonwoven fabric layer A1 on the side of the sheet that is in contact with the smooth roll surface, and at least phosphoric acid is added to the surface of the spunbond nonwoven fabric layer A1 side. By applying a liquid containing an ester to the smooth surface formed in the above step, variations in antistatic properties can be suppressed, and a laminated nonwoven fabric having intended antistatic properties can be obtained. can.

As a method for applying a liquid containing at least a phosphate ester to the sheet, the solution is wound up from a chemical bath filled with the liquid by a metal roll rotating in the chemical bath, and the laminated nonwoven fabric is brought into contact with the upper side of the metal roll. Examples include a roll coating method, a gravure method, a flexographic method, a spray coating method, etc., in which a liquid is transferred to the surface of the laminated nonwoven fabric. Among them, the roll coating method can be used because it has excellent productivity, can uniformly apply the solution, can easily adjust the amount of liquid applied, and can apply liquid only to one side of the laminated nonwoven fabric. preferable.

Further, it is more preferable that the liquid (the liquid containing at least the phosphate ester) further contains silicone. By doing so, a higher water pressure resistance can be maintained.

It should be noted that this liquid can be in the form of solution, emulsion, etc., according to the characteristics of the phosphate ester.

After applying the liquid, it is preferable to dry the solvent contained in the solution. As the drying method, a method of drying with hot air and infrared rays, a method of drying by contact with a heat source, and the like may be used.

[Protective clothing]
In the protective clothing of the present invention, the laminated nonwoven fabric is preferably used at least in the front body. By using the laminated nonwoven fabric at least on the front body, it is possible to protect the wearer's body from harmful mist and floating dust.

As the protective clothing of the present invention, for example, JIS T8115: 2015 "Chemical protective clothing", "4.5 Sealing clothing for spray protection (type 4)", for protecting the wearer from spray liquid chemical substances The full-body chemical protective clothing with the structure of "4.6 Sealing clothing for protection from suspended solid dust (Type 5)", the full-body chemical protective clothing with the structure to protect the wearer from suspended solid dust, "4.7 Sealing clothing for mist protection (type 6)", which is a full-body chemical protective clothing structured to protect the wearer from misty liquid chemicals. And, it can be in the form of one-piece coveralls or upper and lower garments, and can also include a hood, visor, and booties according to the desired mode. In addition, JIS T8122: 2015 "Protective clothing against biologically hazardous substances", "3.2 Whole body protective clothing for biohazard countermeasures" Protective clothing for hazard countermeasures, full body for non-airtight, non-positive pressure biohazard countermeasures to protect the wearer from biologically hazardous substances such as liquid or suspended solid dust described in "3.5 Sealed clothing" Protective clothing is also included.

In addition, the protective clothing of the present invention is a chemical protective clothing having a structure that protects a part of the body, for example, "4.8 partial chemical protective clothing (type PB)" of JIS T8115:2015 "chemical protective clothing" 80% or more of the mass of chemical protective clothing with a structure that protects a part of the body described in 1., which is an apron, footwear cover, gown, hood, jacket, lab coat, arm cover, smock, etc. It is preferable that 100% or less is the laminated nonwoven fabric. Even in this case, the wearing part can be effectively protected from harmful mist and floating dust.

Alternatively, protective clothing for biohazard countermeasures that is structured to protect a part of the body, for example, JIS T8122: 2015 "Protective clothing against biologically hazardous substances", "3.6 Whole body protective clothing for biohazard countermeasures" , which is a protective clothing that protects the body from permeation of biohazardous substances, such as gowns, surgical clothing, laboratory clothing, jackets, trousers, aprons, etc. JIS T8122: 2015 "Protective clothing against biologically hazardous substances", "3.7 Whole body protective clothing for biohazard countermeasures", partial protective equipment such as caps, shoe covers, arm covers, etc. In the case of protective equipment for protecting against permeation of biologically hazardous substances, it is preferable that 80% or more and 100% or less of the mass is the laminated nonwoven fabric. Even in this case, the wearing part can be effectively protected from harmful mist and floating dust.

The protective clothing of the present invention can be manufactured by a known method.

The laminated nonwoven fabric of the present invention will be specifically described based on examples. In the measurement of each physical property, unless otherwise specified, the measurement was performed according to the method described above.

(1) MFR of polyolefin resin (g/10 min):
The MFR of the polyolefin resin (A) and the polyolefin resin (B) was measured under the conditions of a load of 2.16 kg and a temperature of 230° C. for the polypropylene resin, and a load of 2.16 kg and a temperature of 230° C. for the polyethylene resin. Measurement was performed at 190°C.

(2) Spunbond nonwoven fabric layers A1 and A2, meltblown nonwoven fabric layer B, laminated nonwoven fabric basis weight (g/m ² )
Spunbond nonwoven fabric layers A1 and A2 and meltblown nonwoven fabric layer B are separately placed on a collection net under the same conditions as (spunbond nonwoven fabric layer A1), (spunbond nonwoven fabric layer A2), and (meltblown nonwoven fabric layer B) described later. It was measured by the above method from the sampled nonwoven fabric layer. The basis weight of the laminated nonwoven fabric was measured by the method described above.

(3) Average single fiber diameter (μm) of spunbond nonwoven fabric layers A1 and A2 and meltblown nonwoven fabric layer B
As a scanning electron microscope, "VHX-D500" manufactured by KEYENCE CORPORATION was used, and measurement was performed by the method described above.

(4) Thicknesses of spunbond nonwoven fabric layers A1 and A2, meltblown nonwoven fabric layer B, and laminated nonwoven fabric (t _A1 , t _A2 , t _B , t (μm))
As a scanning electron microscope, "VHX-D500" manufactured by KEYENCE CORPORATION was used, and measurement was performed by the method described above.

(5) Heights H ₁ and H ₂ of non-fused portions, ratio of heights (H ₂ /H ₁ )
As a scanning electron microscope, "VHX-D500" manufactured by KEYENCE CORPORATION was used, and measurement was performed by the method described above.

(6) Water pressure resistance per unit basis weight of laminated nonwoven fabric ((mmH ₂ O)/(g/m ² )):
A water pressure tester "Hydrotester" (FX-3000-IV type) manufactured by Textest, Switzerland was used. The calculated water pressure resistance (mmH ₂ O) is rounded off to the second decimal place from the following formula from the basis weight (g/m ² ) obtained based on the above method, and the water pressure resistance per unit basis weight is calculated. Calculated.
Water pressure resistance per unit basis weight = water pressure resistance (mmH ₂ O) / basis weight (g/m ² ).

(7) Surface electrical resistance (Ω) of laminated nonwoven fabric:
The surface electrical resistance of the laminated nonwoven fabric conforms to the European standard (EN1149-1:2006) and was measured using a digital ultra-high resistance/micro current meter 8340A manufactured by ADC by the following procedure.
A. Ten test pieces of 10 cm×10 cm are taken from the laminated nonwoven fabric.
B. One surface of the test piece is set in contact with the measuring part of the device, a voltage of 100 V is applied, and the surface electric resistance value is recorded 15 seconds later.
C. The surface electrical resistance of the other surface of the test piece is similarly recorded, and the smaller value is taken as the surface electrical resistance of the test piece.
D. The above 10 sheets were measured, the average value was calculated, and the surface electrical resistance was obtained with two significant digits.

(8) Permeability per unit basis weight of laminated nonwoven fabric ((cm ³ /(cm ² ·sec))/(g/m ² )):
The air permeability was measured according to the method described above. The permeation rate (cm ³ /(cm ² ·sec)) calculated based on the basis weight (g/m ² ) obtained based on the above method is rounded off to the third decimal place by the following formula. The permeation amount per basis weight was calculated.
Permeability per unit basis weight = Permeability (cm ³ /(cm ² ·sec)) / basis weight (g/m ² ).

[Method for preparing coating solution]
[Coating liquid A]
Add 58.8 g of sodium lauryl phosphate (CAS registration number: 50957-96-5) and 1.2 g of silicone oil (“KF-96-10CS” manufactured by Shin-Etsu Chemical Co., Ltd.) to 1940 g of pure water at room temperature. , and mixed by stirring under atmospheric pressure to obtain a coating liquid A.

[Coating solution B]
A coating liquid B was obtained in the same manner as the coating liquid A, except that the silicone oil was not used in the coating liquid A.

[Coating fluid C]
Coating Liquid C was obtained in the same manner as Coating Liquid A, except that sodium lauryl phosphate was not used in Coating Liquid A.

[Example 1]
(Spunbond nonwoven fabric layer A1)
A homopolymer polypropylene resin having an MFR of 200 g/10 min and a melting point of 163° C. is melted with an extruder, and is spun at a spinning temperature of 235° C. and a single hole discharge rate of 0.40 g/min from a rectangular nozzle with a hole diameter of φ0.30 mm and a hole depth of 2 mm. conditions. After the spun yarn is cooled and solidified, it is pulled and stretched by compressed air in a rectangular ejector at an ejector pressure of 0.35 MPa, collected on a moving net, and made of polypropylene long fibers. A 33 g/m ² spunbond nonwoven layer A1 was formed. The average single fiber diameter of the fibers constituting the formed spunbond nonwoven fabric layer A1 was 11.2 μm.

(Meltblown nonwoven fabric layer B)
A polypropylene resin consisting of a homopolymer having an MFR of 1100 g/min was melted in an extruder and spun from a spinneret with a hole diameter of φ0.25 mm at a spinning temperature of 260° C. and a single hole discharge rate of 0.10 g/min. Thereafter, air was jetted onto the yarn under conditions of an air temperature of 290° C. and an air pressure of 0.10 MPa, and collected on the spunbond nonwoven fabric layer A1 to form a melt blown nonwoven fabric layer B. The melt-blown nonwoven fabric layer B had a basis weight of 10 g/m ² and an average single fiber diameter of 1.1 µm.

(Spunbond nonwoven fabric layer A2)
On the meltblown nonwoven fabric layer B, the spunbond nonwoven fabric layer A1 was formed under the conditions where the single hole discharge rate was changed to 0.20 g / min, and the polypropylene long fibers were collected, and the spunbond with a basis weight of 17 g / m ² was obtained. A nonwoven fabric layer A2 was formed. The spunbond nonwoven fabric layer A2 had a basis weight of 17 g/m ² and an average single fiber diameter of the constituent fibers of 8.7 µm.

(Laminated nonwoven fabric)
By the above method, a laminated fiber web having a total basis weight of 60 g/m ² and comprising a laminate of spunbond nonwoven fabric layer A1, meltblown nonwoven fabric layer B, and spunbond nonwoven fabric layer A2 was obtained. Next, the obtained laminated fiber web is subjected to a pair of upper and lower thermal embossing rolls, each of which is composed of an embossing roll made of metal engraved with a polka dot pattern and having a bonding area ratio of 16% as the upper roll, and a metal flat roll as the lower roll. was used to perform thermal bonding under the conditions of a linear pressure of 300 N/cm and a thermal bonding temperature of 130°C. On the lower layer side of the heat-bonded laminated fiber web, using a metal roll that rotates in the chemical tank at a speed of 10% of the web conveying speed, the coating liquid A is attached, and the dryer set at 120 ° C. Volatile components were removed by passing for 1 second to obtain a laminated nonwoven fabric. Table 1 shows the results and the like.

[Example 2]
In (Spunbond nonwoven fabric layer A1) of Example 1, the single hole discharge rate was 0.40 g/min, but it was changed to 0.45 g/min. was 0.20 g/min, a laminated nonwoven fabric was obtained in the same manner as in Example 1, except that it was changed to 0.15 g/min. Table 1 shows the results and the like.

[Example 3]
In (Spunbond nonwoven fabric layer A1) of Example 1, the single hole discharge rate was 0.40 g/min. was 0.20 g/min, a laminated nonwoven fabric was obtained in the same manner as in Example 1, except that it was changed to 0.24 g/min. Table 1 shows the results and the like.

[Example 4]
A laminated nonwoven fabric was obtained in the same manner as in Example 1, except that the coating liquid A was applied to the (laminated nonwoven fabric) of Example 1, except that the coating liquid B was used. Table 1 shows the results and the like.

[Example 5]
In (spunbond nonwoven fabric layer A1), (meltblown nonwoven fabric layer B), and (spunbond nonwoven fabric layer A2) of Example 1, except that the movement speed of the net for collecting fibers was changed to 1.5 times that of Example 1. obtained a laminated nonwoven fabric in the same manner as in Example 1. Table 1 shows the results and the like.

[Example 6]
A laminated nonwoven fabric was obtained in the same manner as in Example 1, except that the single hole discharge rate of (meltblown nonwoven fabric layer B) of Example 1 was 0.10 g/min, but was changed to 0.05 g/min. Table 2 shows the results and the like.

[Example 7]
In the (laminated nonwoven fabric) of Example 1, as a pair of upper and lower thermal embossing rolls, an embossing roll made of metal engraved with a polka dot pattern and having a bonding area ratio of 16% is used as the upper roll, and a metal flat roll is used as the lower roll. When using a pair of upper and lower thermal embossing rolls, the upper roll was changed to a metal flat roll, and the lower roll was changed to a metal embossing roll with a polka dot pattern engraving and an adhesion area ratio of 16%. , to obtain a laminated nonwoven fabric in the same manner as in Example 1. Table 2 shows the results and the like.

[Example 8]
A laminated nonwoven fabric was obtained in the same manner as in Example 7, except that the single hole discharge rate of (meltblown nonwoven fabric layer B) of Example 7 was 0.10 g/min, but was changed to 0.05 g/min. Table 2 shows the results and the like.

[Comparative Example 1]
In (Spunbond nonwoven fabric layer A1) of Example 1, the single hole discharge rate was 0.40 g/min. was 0.20 g/min, a laminated nonwoven fabric was obtained in the same manner as in Example 1, except that it was changed to 0.30 g/min. Table 3 shows the results and the like.

[Comparative Example 2]
In (Spunbond nonwoven fabric layer A1) of Example 1, the single hole discharge rate was 0.40 g/min, but it was changed to 0.48 g/min. was 0.20 g/min, a laminated nonwoven fabric was obtained in the same manner as in Example 1, except that it was changed to 0.12 g/min. Table 3 shows the results and the like.

[Comparative Example 3]
A laminated nonwoven fabric was obtained in the same manner as in Example 1, except that the meltblown nonwoven fabric layer B was not formed. Table 3 shows the results and the like.

[Comparative Example 4]
A laminated nonwoven fabric was obtained in the same manner as in Example 1, except that the coating liquid A was applied to the (laminated nonwoven fabric) of Example 1, except that the coating liquid C was applied. Table 3 shows the results and the like.

[Comparative Example 5]
In the (laminated nonwoven fabric) of Example 1, a laminated nonwoven fabric was obtained in the same manner as in Example 1, except that when the coating liquid A was applied, the coating liquid was not applied. Table 3 shows the results and the like.

The laminated nonwoven fabrics of Examples 1 to 8 contain a phosphate ester in the spunbond nonwoven layer _A1 , and the ratio ( _{t A1} /t _A2 ) was 1.5 or more and 3 or less, and the water pressure resistance per unit basis weight was 15 mmH ₂ O/(g/m ² ) or more, indicating excellent water resistance.

On the other hand, the laminated nonwoven fabric of Comparative Example 1 had t _A1 /t _A2 of less than 1.5 and was inferior in water resistance. Further, the laminated nonwoven fabric of Comparative Example 2 had t _A1 /t _A2 exceeding 3, and the melt-blown nonwoven fabric layer B was damaged in the lamination process, and thus was inferior in water resistance. Since the laminated nonwoven fabric of Comparative Example 3 did not contain the melt blown nonwoven fabric layer B, the water pressure resistance was low. Since the laminated nonwoven fabrics of Comparative Examples 4 and 5 did not contain phosphate ester in the spunbond nonwoven fabric layer, the surface electrical resistance was high and the antistatic performance was low.

11: Laminated nonwoven fabric 12: Spunbond nonwoven fabric layer A1
13: Meltblown nonwoven fabric layer B
14: Spunbond nonwoven fabric layer A2
15: fused portion 16: non-fused portion

Claims (8)

1. A spunbond nonwoven fabric layer A1 made of fibers made of a polyolefin resin and containing at least a phosphate ester is arranged on one surface,
   A spunbond nonwoven fabric layer A2 made of fibers made of polyolefin resin is arranged on the other surface,
   A laminated nonwoven fabric in which at least one melt-blown nonwoven fabric layer B composed of fibers made of a polyolefin resin is arranged between the spunbond nonwoven fabric layer A1 and the spunbond nonwoven fabric layer A2,
   The ratio (t A1 /t _{A2 ) of the thickness (t A1} ) of the spunbond nonwoven fabric layer A1 to the thickness ( _{t A2} ) of the spunbond nonwoven fabric layer A2 in the non-fused portion of the laminated nonwoven fabric is _1.5 or more. Laminated nonwoven fabric, which is 3.0 or less.
2. The height _H1 of the non-fused portion on the one surface of the laminated nonwoven fabric is 50 μm or more and 200 μm or less, and the ratio of the height _H2 of the non-fused portion on the other surface to the height _H1 ( The laminated nonwoven fabric according to claim 1, wherein _H2 / _H1 ) is 1.1 or more and 4.0 or less.
3. The laminated nonwoven fabric according to claim 1, wherein the spunbond nonwoven fabric layer A1 further contains silicone.
4. The laminated nonwoven fabric according to claim 1, wherein the ratio ( _tB /t) of the thickness (tB) of the melt blown nonwoven fabric layer _B to the thickness (t) of the entire laminated nonwoven fabric is 0.05 or more and 0.15 or less. .
5. A method for producing a laminated nonwoven fabric according to claim 1,
   forming a spunbond nonwoven layer, forming at least one meltblown nonwoven layer thereon, and further forming a spunbond nonwoven layer thereon to form a laminate;
   a step of fusing the laminate using a thermal embossing roll, which is a combination of a roll having a smooth surface on one side and a roll having an engraved surface on the other side, to obtain a sheet;
   A spunbond nonwoven fabric layer A1 is defined as the spunbond nonwoven fabric layer A1 on the side of the sheet that is in contact with the roll having a smooth roll surface, and a liquid containing at least a phosphate ester is applied to the surface of the spunbond nonwoven fabric layer A1. and
   A method for producing a laminated nonwoven fabric, comprising:
6. The method for producing a laminated nonwoven fabric according to claim 5, wherein the liquid further contains silicone.
7. A protective garment in which the laminated nonwoven fabric according to claim 1 is used at least in the front body.
8. A protective clothing in which 80% or more and 100% or less of the mass is the laminated nonwoven fabric according to claim 1.

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