JP7322661B2 - Method for manufacturing nonwoven products using processed nonwoven fabric - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a nonwoven product, and more particularly to a method for manufacturing a nonwoven product using a nonwoven fabric containing a thermoplastic resin and a lubricant.

BACKGROUND ART Conventionally, nonwoven fabrics have been used in various applications such as disposable diapers, sanitary products, other sanitary products, clothing materials, bandages, and packaging materials. In this way, the nonwoven fabric is often used for applications that come into direct contact with the body, and from the viewpoint of good wearing feeling and comfort on the body, improvement of the touch and texture is required. Technology has been developed. For example, non-woven fabrics that make up disposable diapers and the like come into direct contact with the skin of infants, so they need to be particularly soft and soft to the touch.

As a method for improving texture such as touch feeling of a nonwoven fabric, there is a method of adding an additive such as a lubricant to the nonwoven fabric. In this technique, the added lubricant is allowed to bleed onto the surface of the nonwoven fabric, thereby improving the feel and texture of the nonwoven fabric (see, for example, Patent Documents 1 and 2).

On the other hand, the bleeding of the lubricant depends on the compatibility between the thermoplastic resin and the lubricant, and is easily affected by the environmental temperature. For example, in winter when the temperature is low, the amount of bleeding on the surface of the nonwoven fabric decreases, and the feel of the nonwoven fabric and the coefficient of friction on the surface of the nonwoven fabric increase. Therefore, it has been necessary to adjust the amount of lubricant to be added and the equipment for manufacturing nonwoven fabric products for each season.

JP 2002-38364 A WO2012/105567

In view of the above, the object of the present invention is to provide a method for providing a nonwoven fabric having a stable coefficient of friction throughout the year without being affected by the external environment such as temperature, and a method for manufacturing a nonwoven fabric product by processing it. That's what it is.

The present invention for solving the above problems has the following aspects.

In one embodiment of the present invention, the steps of providing a thermoplastic resin, mixing a masterbatch containing a lubricant at a concentration of 8% or more with the thermoplastic resin to form a resin composition, and the resin composition Provided is a method for producing a nonwoven fabric, comprising the steps of: producing a nonwoven fabric from a material; and heat-treating the nonwoven fabric at a temperature of 35°C to 45°C.

In one embodiment of the present invention, the thermoplastic resin has a melting point of 100° C. or higher. In another embodiment, the lubricant is fatty acid amide having 15 to 22 carbon atoms, and the lubricant is contained in the nonwoven fabric. It is characterized by containing 1000 to 6000 ppm.

In one embodiment of the present invention, the nonwoven fabric may be manufactured by spunbonding, and in another embodiment, the thermoplastic resin is a polypropylene resin.

In one embodiment of the present invention, the lubricant may be erucamide, and in another embodiment, the heat treatment is carried out by holding for 2.5 hours or longer.

Furthermore, in one embodiment of the present invention, the heat treatment may be carried out in a state in which the nonwoven fabric is packaged in a sheet having a moisture permeability of 100 g/m ² ·d or less to block humidity.

In one embodiment of the present invention, the steps of providing a thermoplastic resin, mixing a masterbatch containing a lubricant at a concentration of 8% or more with the thermoplastic resin to form a resin composition, and the resin composition and a step of heat-treating the nonwoven fabric at a temperature of 35° C. to 45° C., unpacking it in an environment of 30° C. or less, and processing it to produce a nonwoven fabric product. The present invention relates to a method for manufacturing nonwoven products.

The nonwoven fabric of the present invention can have a stable coefficient of friction throughout the year without being affected by the external environment such as temperature.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

A. Nonwoven fabric The nonwoven fabric processed in the present invention is manufactured from a resin composition containing a thermoplastic resin and a lubricant.

A-1. Thermoplastic resin The thermoplastic resin used in the present invention is compatible with the lubricant described later, and preferably has a melting point of 100°C or higher. Specifically, polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polytrimethylene terephthalate; polyimide resins; polyamide resins such as nylon 6,6, and copolymers thereof. Coalesces as well as mixtures thereof can be used. The thermoplastic resin of the present invention may be a mixture of two or more resins having different crystallinities.

In one embodiment of the present invention, the thermoplastic resin may be an olefin resin. The olefinic resin that can be used in the present invention is preferably an olefinic polymer obtained by polymerizing one or more monomers selected from ethylene and α-olefins having 3 to 28 carbon atoms. Polypropylene resin is particularly preferred. The olefinic resin used in the present invention may be a mixture of a low-melting, low-crystalline resin and a high-melting, high-crystalline resin.

The molecular weight of the thermoplastic resin used in the present invention varies depending on the monomer used and the melting point. As one embodiment of the present invention, the polypropylene resin preferably has a weight average molecular weight of 100,000 to 200,000.

A-2. Lubricant The lubricant used in the present invention is not particularly limited as long as it is compatible with the thermoplastic resin and partly bleeds out on the fiber surface at the product use temperature. Examples include fatty acid amide compounds; fatty acid compounds; paraffins and hydrocarbon resins; silicone compounds; silicone polymers; fluorine compounds, copolymers of tetrafluoroethylene and propylene, copolymers of vinylidene fluoride and hexafluoropropylene and mixtures thereof can be used. In one embodiment of the invention, the lubricant is preferably a fatty acid amide compound.

Fatty acid amide compounds include fatty acid monoamide compounds, fatty acid diamide compounds, saturated fatty acid monoamide compounds, and unsaturated fatty acid diamide compounds. Fatty acid amides having 15 to 22 carbon atoms are preferred. Specifically, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, montanic acid amide, N,N'-methylene-bis-lauric acid amide, N,N'-methylene-bis-myristic acid amide, N,N'-methylene-bis-palmitic acid amide, N,N'-methylene-bis-behenic acid amide, N,N'-methylene-bis-oleic acid amide, N,N'-methylene-bis-erucamide, N,N'-ethylene-bis-oleic acid amide, N,N'-ethylene-bis-erucic acid amide and the like, and a plurality of these in combination may be used. Erucamide is particularly preferred.

The content of the lubricant in the present invention is not particularly limited, and is, for example, in the range of 0.01 to 1% by mass, preferably 0.1 to 0.5% by mass in the resin composition. This content is determined by comprehensively judging the type of thermoplastic resin, crystallinity, resin properties such as MFR, type of lubricant, required properties of the resulting nonwoven fabric, heat treatment conditions, and the like.

For example, when polypropylene resin is used as the thermoplastic resin and erucamide is used as the lubricant, the range is preferably 800 to 8000 ppm, particularly 1000 to 6000 ppm, relative to the resin composition. In this case, depending on the processing conditions, if it is less than 800 ppm, it may be difficult to control the static friction coefficient of the nonwoven fabric within the range of 0.1 to 0.4. The amount of becomes large, and it may cause deterioration of appearance such as generation of white powder, and deterioration of heat-sealability and secondary workability.

Also, in one embodiment of the present invention, the lubricant is added to the thermoplastic resin by a masterbatch method. The concentration of the lubricant added to the masterbatch is preferably 8% or more. More preferably it is 10%. By using such a high-concentration masterbatch, the amount of the masterbatch added to the raw material resin can be reduced, and the spinnability can be improved.

A-3. Other Additives The nonwoven fabric to be processed in the present invention is generally used for nonwoven fabric products, such as for the purpose of nonwoven products and for imparting properties, as long as it does not affect the properties during processing of the nonwoven fabric after heat treatment, which will be described later. Known additive components such as those described above can be added. Examples of these known additive components include neutralizing agents such as calcium stearate and hydrotalcite, antioxidants such as phenolic, phosphorus, and sulfur antioxidants, heat stabilizers, nucleating agents, ultraviolet absorbers, and light stabilizers. agents, antistatic agents, flame retardants, pigments, dyes, or inorganic powders such as silica, talc, calcium carbonate, calcium oxide and magnesium oxide.

B. Manufacturing method of processed nonwoven fabric B-1. Production of nonwoven fabric before treatment The nonwoven fabric processed in the present invention may be produced using either long fibers or short fibers formed from the resin composition containing the thermoplastic resin and lubricant. As a method for obtaining a nonwoven fabric, a known method can be adopted. For example, the spunbond method, meltblown method (meltblown method), spunlace method, thermal bond method, chemical bond method, airlaid method, needle punch method, flash spinning, and the like can be mentioned. In one embodiment of the present invention, meltblown or spunbond methods are preferred, and spunbond methods are more preferred.

B-2. Nonwoven fabric heat treatment (aging treatment)
In one embodiment of the present invention, the nonwoven fabric produced by the above method is subjected to heat treatment (aging treatment) before processing. The heat treatment is performed at a temperature at which the lubricant bleeds from the thermoplastic resin, and may be determined based on the combination of thermoplastic resin and lubricant. For example, when a polypropylene-based resin is used as the thermoplastic resin, the temperature is preferably 35°C to 45°C.

Also, in one embodiment of the present invention, the heat treatment is conducted for a time sufficient to bleed about 50% of the lubricant added to the nonwoven. For example, heat treatment may be performed by holding the nonwoven fabric at a temperature of 35° C. to 45° C. for 2.5 hours or more. In another embodiment of the present invention, the heat treatment is performed in a state in which the nonwoven fabric is packed in a sheet such as a film having a low moisture permeability of 100 g/m ² ·d or less and is not in direct contact with humidity. may If there is no packing sheet, there is a risk of contamination by foreign matter, and in a high humidity environment, water vapor may enter during winding and condensation may occur when the temperature drops. These troubles can be prevented by sealing with a packing sheet.

Due to the heat treatment, a certain amount or more of the lubricant bleeds onto the fiber surface, and the coefficient of friction of the nonwoven fabric surface decreases. It is difficult to re-dissolve in the fiber, and the coefficient of friction of the nonwoven fabric after heat treatment can be kept low.

C. Processing of Nonwovens In one embodiment of the present invention, heat-treated nonwovens, as described above, are processed to produce nonwoven products. After the heat treatment, the nonwoven fabric may be processed as it is, or may be processed after being cooled to an appropriate temperature such as room temperature.

The nonwoven fabric product produced by the method of the present invention is not particularly limited, but examples include members for disposable diapers, elastic members for diaper covers, elastic members for sanitary products, elastic members for sanitary products, elastic tapes, and bandages. , elastic material for clothing, insulating material for clothing, thermal insulation material for clothing, protective clothing, hat, mask, glove, supporter, elastic bandage, poultice base cloth, non-slip base cloth, vibration absorbing material, finger cot, Air filters for clean rooms, electret filters with electret processing, separators, heat insulating materials, coffee bags, food packaging materials, ceiling skin materials for automobiles, soundproofing materials, cushion materials, speaker dustproof materials, air cleaner materials, insulator skins, backing materials , Adhesive non-woven fabric sheets, various automotive parts such as door trims, various cleaning materials such as copying machine cleaning materials, surface and backing materials for carpets, agricultural rolled cloth, wood drains, shoe materials such as sports shoe skins, and bags Components, industrial seals, wiping materials, sheets, and the like can be mentioned. In particular, one embodiment of the present invention is preferably used for manufacturing sanitary products such as disposable diapers.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

[Measurement of bleed-out amount of lubricant]
1 g of a nonwoven fabric sample was collected, and after eluting the lubricant that had bled to the surface with methanol, the amount of the lubricant in the solvent was quantitatively analyzed by the GC-MS method to measure the amount of bleeding.

[Measurement of friction coefficient of nonwoven fabric]
In accordance with JIS K7125, using a HEIDON surface property measuring machine (14DR: manufactured by Shinto Kagaku Co., Ltd.), the nonwoven fabrics were brought into contact with each other, and the dynamic friction coefficient was measured at 5 points with a contact surface of 40 cm ² and a load of 200 g at a speed of 100 mm / min. The average value was taken as the coefficient of friction.

[Moisture permeability measurement of film]
A 100 mm square piece of the film was cut out, and moisture permeability was measured at 40° C. and 90% RH according to JISK7129.

[Example 1: Production of nonwoven fabric 1]
A kneading extruder (Japan It was mixed with a metering mixer in a resin pellet hopper installed upstream of the raw material charging position in a single-screw kneading extruder (caliber 40 mm, manufactured by Steel Works).

In the kneading extruder, the screw rotation speed is adjusted so that the extrusion rate is 100 to 200 kg / hour, and the molten resin is produced and introduced into a spinneret (die) equipped with a large number of spinning holes (nozzles), Dispense. Thereafter, the melt-spun filaments are introduced into a cooling chamber, cooled by cooling air, and then drawn (pulled) by drawing air to deposit aggregates of filaments on a moving collection surface. A spunbonded nonwoven fabric was formed by partially heat-sealing the accumulated long fiber assembly with an embossing roll. The obtained nonwoven fabric was wound with a winder and split into 500 mm wide strips with a slitter to produce a nonwoven fabric roll with a length of 10,000 m. /m ² ·d).

The packaged product was stored in a storage room at room temperature of 40° C. for 3 hours, and then unpacked in an environment of 20° C. to measure the amount of erucamide bleeding and the coefficient of friction of the nonwoven fabric.

[Example 2: Production of nonwoven fabric 2]
A spunbond nonwoven fabric was formed in the same manner as in Example 1, except that the polypropylene resin (melting point 162° C., MFR 60 g/10 min) was changed to 95 parts and the master batch was changed to 5 parts.

[Comparative Example 1: Production of nonwoven fabric A1]
A nonwoven fabric roll was produced in the same manner as in Example 1, and the amount of bleeding of erucamide and the coefficient of friction of the nonwoven fabric were measured in the same manner as in Example 1, except that the roll was held in an environment of 20° C. for 3 hours after packing.

[Comparative Example 2: Production of nonwoven fabric A2]
A nonwoven fabric roll was produced in the same manner as in Example 1, and the amount of bleeding of erucamide and the coefficient of friction of the nonwoven fabric were measured in the same manner as in Example 1, except that after packing, the roll was kept in a heat-retaining cabinet at 60° C. for 3 hours.

[Comparative Example 3: Influence of packing material]
After manufacturing a nonwoven fabric roll in the same manner as in Example 1, the amount of bleeding of erucamide and the coefficient of friction of the nonwoven fabric were measured in the same manner as in Example 1, except that Harden film (water vapor permeability: 180 g/m ² ·d) was used as the packaging film. It was measured.

Claims (7)

providing a thermoplastic resin;
A step of mixing a masterbatch containing a lubricant at a concentration of 8% or more with the thermoplastic resin to form a resin composition;
a step of producing a nonwoven fabric from the resin composition;
a step of heat-treating the nonwoven fabric by holding it at a temperature of 35° C. to 45° C. for 2.5 hours or more ;
including
A method for producing a nonwoven fabric, characterized in that the nonwoven fabric is packed in a sheet having a moisture permeability of 100 g/m ² ·d or less, and is carried out in a moisture-blocked state, and unwrapped in an environment of 30°C or less. 2. The manufacturing method according to claim 1, wherein the thermoplastic resin has a melting point of 100[deg.] C. or higher. 3. The manufacturing method according to claim 1, wherein the lubricant is a fatty acid amide having 15 to 22 carbon atoms, and the nonwoven fabric contains 1000 to 6000 ppm of the lubricant. The manufacturing method according to any one of claims 1 to 3, wherein the nonwoven fabric is manufactured by a spunbond method. The manufacturing method according to any one of claims 1 to 4, wherein the thermoplastic resin is a polypropylene resin. The production method according to any one of claims 1 to 5, wherein the lubricant is erucamide. providing a thermoplastic resin;
A step of mixing a masterbatch containing a lubricant at a concentration of 8% or more with the thermoplastic resin to form a resin composition;
a step of producing a nonwoven fabric from the resin composition;
a step of heat-treating the non-woven fabric by holding the non-woven fabric at a temperature of 35° C. to 45° C. for 2.5 hours or more, and then processing the non-woven fabric to produce a non-woven fabric product;
including
A method for producing a nonwoven fabric product, characterized in that the nonwoven fabric is packed in a sheet having a moisture permeability of 100 g/m ² ·d or less, is carried out in a moisture-blocked state, and is unpacked in an environment of 30°C or less.