JPS59137552A - Nonwoven fabric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to nonwoven fabrics. More specifically, the present invention relates to a thermally bonded nonwoven fabric with a low basis weight, high strength, soft texture, and no slimy feeling.

In recent years, nonwoven fabrics have been used in cosmetic puffs, disposable diapers,
Significant progress has been made in the field of surface materials such as sanitary napkins. In such applications, it is required that the nonwoven fabric maintains high strength with as little nonwoven weight as possible, has little fluffing, and has as soft a texture as possible and a good feel to the touch. Conventionally, nonwoven fabrics for such uses are heat-treated webs made of composite fibers (hereinafter sometimes referred to as composite thermally bonded fibers) containing fiber-forming polymers with different melting points as composite components, and the bond between the fibers is Nonwoven fabrics (hereinafter sometimes referred to as thermally bonded nonwoven fabrics) whose polymorphism is stabilized by the fusion of low melting point components at contact points have been used. In this case, polyolefin or polyester is used as the fiber-forming polymer.

In order to maintain as high a nonwoven fabric strength as possible with as little nonwoven fabric weight as possible, and to obtain a nonwoven fabric that has as soft a texture as possible, it is necessary to use composite thermal adhesive fibers with a monofilament fineness as small as possible. You need to use . However, hydrophobic fibers such as polyolefin or polyester have the disadvantage that they give a waxy and slimy feel to the skin, and their fineness is particularly small. It was obvious.

As a result of intensive research into ways to improve the above-mentioned drawbacks of nonwoven fabrics made of polyolefin or polyester, the inventors of the present invention have found that composite heat-adhesive fibers have a foamed structure (hereinafter sometimes referred to as heat-adhesive foamed fibers), and The present invention was completed based on the knowledge that the desired object can be achieved by heat-treating the web made of the heat-adhesive foam fibers using an embossing roll.

The thermoadhesive foam fiber used in the present invention is a parallel type or sheath-core type composite fiber made of fiber-forming polymers with different melting points, and the low melting point component of the composite is dominant on the fiber surface. It refers to a polyolefin-based or polyester-based foamed conjugate fiber that is formed and contains air bubbles, some of which are cleaved onto the fiber surface, and has a single fiber fineness of 0.5 to 15 deniers.

Such foamed composite fibers are disclosed in Japanese Patent Application No. 57-1510, for example.
As disclosed in No. 48, it can be obtained by blending a blowing agent only into the low melting point component side of the composite fiber during spinning of the composite fiber.

Composite components include polypropylene/high-density polyethylene, polypropylene/ethylene propylene butene-1
Examples include combinations of terpolymer, polypropylene/(polyethylene + ethylene/vinyl acetate copolymer mixture), 9 normal polyester/low melting point polyester, and the difference in softening point between the high melting point component and the low melting point component is 20°C or more. (preferably 30°C or higher) is suitable.

The above-mentioned ordinary polyester is a polymer mainly composed of polyethylene terephthalate, and has a melting point of 230 to 270.
°C is preferably used, and low melting point polyesters include polyethylene terephthalate in which part or all of the terentalic acid component is replaced with other dibasic acid components such as isophthalic acid and adipic acid, and furthermore, ethylene glycol components. It is a polymer in which part or all of is substituted with an alkylene glycol having 3 to 10 carbon atoms, particularly butylene glycol, and one having a melting point of 100 to 280'C is preferably used.

There are no particular restrictions on the selection of the blowing agent, and any blowing agent that generates gas at a temperature below the spinning temperature of the low melting point component of the composite fiber can be used, such as azodicarbonamide, barium azodicarboxylate, N, N, etc. Examples thereof include '-dinitrosopentamethylenetetramine, p-toluenesulfonyl semihydrabazide, trihydrazinotriazine, and the like.

These blowing agents are added to the low melting point component side of the composite fiber,
The amount added should preferably be such that some of the bubbles generated are ruptured on the fiber surface, and the actual amount added depends on the desired fineness of the fiber,
Although it is adjusted as appropriate depending on the thickness of the low melting point component, it is generally 0.1 to 2. The ON amount is about %.

Foaming machine synthetic fiber Kjf: is made by spinning the above-mentioned raw materials using a conventionally known parallel type or sheath-core type spinneret, and under spinning conditions appropriately set according to the fiber-forming polymer and blowing agent used. It is obtained by stretching 2 to 8 times so that the single fiber fineness is 0.5 to 15 deniers. The resulting foamed composite fiber has many fine grooves formed by the opened air bubbles on its surface, which greatly improves its texture, and it has a wool-like texture without any slimy feeling. The nonwoven fabric obtained using this method also has a significantly improved feel to the touch. Further, it is necessary that the single fiber fineness of the foamed composite fiber is within the range of 0.5 to 15 deniers. If the single fiber fineness is less than 0.5 denier, the effect of reducing the slimy feeling due to foaming will be insufficient, and the productivity during fiber production will decrease, resulting in an increase in the cost of the nonwoven fabric, which is undesirable.1. If the single fiber fineness exceeds 15 deniers, the effect of reducing the slimy feeling is great, but the fibers are not hard and the texture of the resulting nonwoven fabric is also rough and hard, which is not preferable.

In the present invention, the foamed conjugate fibers are used alone or mixed with other fibers to form a nonwoven fabric.

Other fibers may be used, as long as they do not melt, shrink or deteriorate during heat treatment to form a nonwoven fabric, and have a fineness small enough that the texture of the resulting nonwoven fabric does not become rough or hard. However, for example, natural fibers such as cotton and wool, semi-synthetic fibers such as viscose rayon and cellulose acetate fibers, synthetic fibers such as polyamide fibers, polyolefin fibers, polyester fibers, and acrylic fibers may be selected and used as appropriate. The amount used is 70% by weight or less based on the total amount with the foamed composite fibers. When the proportion of foamed composite fibers in the fiber mixture is less than 80'ii%, the strength of the nonwoven fabric decreases, and especially when the other fibers are hydrophobic synthetic fibers, the texture of the nonwoven fabric improves and the slimy feel is reduced. This is not preferable because the reduction effect will be insufficient.

The foamed conjugate fiber alone or a mixture of the foamed conjugate fiber and other fibers is formed into a web by a known carding method, air lay method, dry pulping method, wet paper making method, etc., and then the softening point of the low melting point component of the foamed conjugate fiber is The above-mentioned material is heated and pressed using an embossing roll in which the total area of the convex portions heated to a temperature below the softening point of the high melting point component is 15 to 50% of the roll area to form a non-woven fabric. If the temperature of the embossing roll is below the softening point of the low melting point component of the foamed conjugate fiber, bonding between the fibers due to heat fusion of the component will not occur, resulting in insufficient strength of the nonwoven fabric, and the temperature will be lower than the softening point of the high melting point component of the foamed conjugate fiber. If the softening point is exceeded, the entire conjugate fiber melts and loses its fiber shape, which is undesirable because the nonwoven fabric loses its bulk and softness.

If the total roughness of the convex area of the embossing roll is less than 15% of the product of one roll, the nonwoven fabric will not have sufficient strength, and if it exceeds 50%, the nonwoven fabric will be bulky, inflexible, paper-like, and have a slimy feel. occurs, which is not desirable.

When the web containing the foamed conjugate fibers used in the present invention is made into a nonwoven fabric using hot air such as a suction drum dryer without using an embossing roll, bulkiness,
Even if satisfactory non-softness and non-woven fabric strength are obtained, the foamed conjugate fiber q) air bubbles and cleavage grooves present on the surface are significantly reduced, making it impossible to reduce the slimy feel.

In contrast, the nonwoven fabric of the present invention is thermally bonded only to 15 to 50% of the surface of the fabric, so it is bulky, flexible, strong, and does not feel slimy. It has an excellent texture and is useful as a surface material for various sanitary materials such as cosmetic puffs, disposable diapers, and amphibious napkins.

The present invention will be specifically explained with reference to Examples and Comparative Examples.The methods for measuring physical properties in each case will be summarized below.

Non-woven sub-strong crab According to JIS L1096, test piece in 2α, gripping interval 10α, elongation speed 9100% per minute
It was measured with

Case: A sensory test was conducted by five panelists, and all of them judged it to have an excellent texture without a slimy feeling.io, i~2
Those judged to have a slimy feel are indicated as Δ, and those judged as slimy by three or more persons are indicated as High-density polyethylene containing 0.8 wt% of calcium stearate and 0.8 wt% of calcium stearate is composited in parallel at a composite ratio of 50/50 wt%, single fiber fineness 3 denier, number of folds 12 threads/inch,
Expanded composite fiber (5) with a fiber length of 641!1 ff (in this fiber, the low melting point component with many cells and cleavage neighbors formed about two-thirds of the fiber surface), 75 wt%, polypropylene and high density. Polyethylene composite ratio 50150wt
Single fiber fineness 3 denier, am
Polyolefin-based primary fiber (B) 'A 5 wt% with several 12.5 threads/inch and fiber length of 64 ym was mixed with 5 wt%, thoroughly opened, and then passed through a cotton loosening machine to form a web with a basis weight of 30 f/yd. did. Next, this web was passed through a pair of rubber M flat rolls, and then passed between eight embossing rolls each having a different convex area heated to 145°C and a metal flat roll kept at room temperature. Pressure 5.2 kg/
cm Conditions Comparative Example 3 T and R A metal flat roll was used in place of the embossing roll.

Examples 5 to 7 The nonwoven fabric of the present invention was bulky, had no slimy feel, had a smooth and crisp texture, and was suitable as a surface material for cosmetic puffs. , Comparison 1+lJ4-6 Low i;y with normal fiber polyester (melting point 250''C) as core component, 0.8wt% azodicarbonamide and 0.8wt% calcium stearate;
l+ point polyester (melting point 135°C) as a sheath component,
i′+ obtained by spinning at a composite ratio of 50/50 wt%,
Monofilament AUW 6 denier, 4 λ reduction number 11 threads/inch:
tRKtiU g 64 wt% of 55T3 foam composite fiber (C) having air bubbles and cleavage grooves in the sheath component;
Single fiber fineness 3 denier, number of crimp 13 threads/inch, fiber length 64
Mix waste polypropylene fiber (c) with 20 wt 'y'o and pass it through a pure cotton machine to a fabric weight of 'M St 40 f/
/n? It was made into a web. Next, this web was passed through a combination roll of a metal flat roll and a rubber flat roll, and then passed through various embossing rolls with different convex areas heated to 147°C and a metal roll kept at room temperature. The material was passed between flat rolls at a pressure of 6 kq/α to obtain a nonwoven fabric, and its properties were evaluated. Results first
Shown in the table.

Examples 8-10. Comparative Examples 7 and 8 The foamed composite fiber (5) and polyolefin composite fiber (B) used in Examples 1 to 4 were mixed and opened at various weight ratios shown in the table, and each was passed through a pure cotton machine to determine the basis weight. 25
The web was f/y/. Next, this web was passed through a pair of rubber flat rolls in the same manner as in Example 1, and then an embossing roll with a total convex area of 48% heated to 140°C and a metal flat roll kept at room temperature. The nonwoven fabric was made into a nonwoven fabric and its properties were evaluated. The results are shown in Table 1.

Example ■ Polypropylene (homopolymer) as a high melting point component,
An ethylene-propylene-phytene-1 ternary covalent combination (melting point: 184°C, melting point: 100°C to 100°C) containing 0.8wt% of azodicarbonamide and 0.8wt% of calcium stearate as low melting point components. , foamed composite fibers with single fiber fineness of 8 denier and fiber length of 51 denier, composited in parallel at a composite ratio of 50/50 wt% (
This fiber was made of rayon (F) with a low melting point component having numerous bubbles and cleavage grooves, which formed about two-thirds of the fiber surface (85 wt%), a single fiber fineness of 3 denier, and a fiber length of 52 tone.
15 wt% was mixed and spread, and passed through a pure cotton machine to form a force-double fiber with a basis weight of 5oy7nr.

This web was then heated to an embossing roll temperature of 145°C and a roll pressure of 5. A nonwoven fabric was obtained by embossing under the same conditions as in Examples 6 to 8 except that s kti /α was used.

The properties of this nonwoven fabric are shown in Table 1.

Example 12 One sheet of non-woven fabric was laminated as a surface material on the top and bottom of bleached cotton of 50 WMX 65 ffff size as the filling, and the upper and lower non-woven fabrics were heated at the outer edge of the filling and melted at the same time as adhesion to make a makeup with a basis weight of 150 f/m. I got the puff. The above-mentioned puffs using the nonwoven fabric obtained in Example 3 or 4 as the surface material were all free from slimy feeling and had an excellent texture rich in crunchy taste. On the other hand, in the case where the nonwoven fabric obtained in Comparative Example 1 was used as the surface material, the surface material broke due to a slight external force and could not be put to practical use. -1, the one using the nonwoven fabric obtained in Lemon row 6 as the surface material is slime #)
It had a rough texture and had a rough and hard texture, which was not desirable.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing examples of the convex pattern of the embossing roll used in the present invention. More than 1 day 0, 0 0 0 o O ○ ○ O○

Claims (1)

[Claims] 1) A structure composed of multiple components with different melting points, in which the low melting point component predominates on the fiber surface, only the low melting point component substantially foams, and at least some of the bubbles are ruptured on the fiber surface. A web consisting of a polyolefin-based or polyester-based conjugate fiber with a single fiber fineness of 0.5 to 15 deniers, or a fiber mixture with other types of fibers containing 80 wt% or more of the conjugate fiber. Embossing that is heated to a temperature above the softening point of the low melting point component and below the softening point of the high melting point component, in which the convex portions are evenly distributed on the roll surface and the sum of the convex areas accounts for 15 to 50% of the roll surface. A nonwoven fabric with a basis weight of 10·-50 f/n/ whose polymorphism is stabilized by heat-pressing with a roll.