JP2994027B2 - Manufacturing method of fiber mixed nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a fiber-mixed nonwoven fabric suitable for use in synthetic leather and artificial leather, and more specifically, shrinks by heat treatment to exhibit a dense and soft feeling. And have high strength,
The present invention relates to a method for producing a fiber-mixed nonwoven fabric that can be suitably used as a base fabric of synthetic leather or artificial leather.

(Prior Art) Conventionally, many attempts have been made to produce nonwoven fabrics made of synthetic fibers similar to natural leather. This nonwoven fabric is usually required to be dense and flexible. For this reason, when producing a nonwoven fabric, polyurethane is applied to a sheet of ultrafine fiber-generating conjugate fiber composed of two types of polymer components having different dissolution characteristics, and then one of the polymer components is removed. JP-A-48-19922), a method of subjecting a web composed of highly shrinkable fibers and easily splittable conjugate fibers to entanglement / shrinkage treatment and splitting of easily splittable conjugate fibers (Japanese Unexamined Patent Publication No. 53-12)
No. 2875) has attempted to make the fibers constituting the nonwoven fabric finer.

However, the method using the ultrafine fiber-generating conjugate fiber composed of two kinds of polymer components having different dissolution characteristics is advantageous in that the ultrafine fiber can be easily obtained. Therefore, there has been a problem that the cost is increased and the obtained nonwoven fabric is lacking in density. In addition, a method using high-shrinkable fiber and easily splittable conjugate fiber can obtain a dense nonwoven fabric, but the cost increases because the conjugate fiber is used, and the obtained nonwoven fabric has a long-term stability of shrinkage performance. However, there is a problem that the strength of the nonwoven fabric is insufficient and the dimensional stability when the final product is pulled is poor.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems and provides not only synthetic leather but also
A base cloth of synthetic leather and artificial leather that expresses a dense and flexible feel suitable for uses of natural leather, especially artificial leather that is close to suede, in terms of function and feel compared to synthetic leather, and has high strength. An object of the present invention is to provide a method for producing a fiber-mixed nonwoven fabric that can be suitably used as a nonwoven fabric.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is, the present invention provides a high shrinkage comprising an acid component having a contraction ratio represented by the following formula and a molar ratio of terephthalic acid / dicarboxylic acid other than terephthalic acid of 96/4 to 88/12 and an ethylene glycol component. Copolymeric polyester fiber A or ethylene glycol /
The molar ratio of diols other than ethylene glycol is 96/4 to 88
A high-shrinkage copolyester fiber A comprising a diol component and a terephthalic acid component, a polyamide fiber B having a single-fiber fineness of 2 denier or less, and a high-melting polyamide polymer as a core component; A heat shrink treatment is applied to a fiber-mixed web in which a core-in-sheath composite fiber C having a low melting point polyamide polymer having a lower melting point than the melting points of the polymers constituting A and B as a sheath component (adhesive component) is mixed. A method for producing a fiber-mixed nonwoven fabric, characterized by: 25 ≦ S ₀ (%) ≦ 70 ΔS (%) ≦ 5 [S ₀ (%) is a method of drying the fiber immediately after production at a temperature of 170 ° C. for 15 minutes. ΔS (%) is the shrinkage ratio when heat-treated, and ΔS (%) is the shrinkage ratio when the fiber immediately after production is left at 40 ° C. for 5 weeks and then dry-heat-treated at 170 ° C. for 15 minutes and the shrinkage ratio S ₀ (%). And the difference. ].

 Next, the present invention will be described in detail.

A first feature of the method for producing a nonwoven fabric of the present invention resides in that the highly shrinkable copolyester fiber A is used as a first component of the nonwoven fabric. The high-shrinkable copolyester fiber A is a copolymer of dicarboxylic acids such as phthalic acid, isophthalic acid, and propanedicarboxylic acid, and has a molar ratio of terephthalic acid / dicarboxylic acid other than terephthalic acid.
Copolymerized polyester composed of an acid component of 96/4 to 88/12 and ethylene glycol component, or a diol such as diethylene glycol, 1,2-propanediol, neopentyl glycol, etc., and other than ethylene glycol / ethylene glycol The molar ratio of the diol is 96/4 ~
It is composed of a copolymer polyester composed of a diol component and a terephthalic acid component of 88/12, and a more dense and soft nonwoven fabric can be obtained.

High shrinkage copolyester fiber A according to the present invention
Means that the shrinkage ratio So when the fiber immediately after production is dry-heat treated at 170 ° C for 15 minutes is the above formula, and the fiber immediately after production is left at 40 ° C for 5 weeks and then dry-heat treated at 170 ° C for 15 minutes. The difference ΔS between the shrinkage rate at that time and the shrinkage rate So satisfies the above-mentioned equations. In the case of the high-shrinkable copolyester-based fiber A, if the shrinkage ratio So is lower than 25%, the tightness of the nonwoven fabric during heat shrinkage treatment is poor, and a dense nonwoven fabric cannot be obtained. On the other hand, if the shrinkage factor So is higher than 70%, the nonwoven fabric becomes too dense and the feel of the nonwoven fabric becomes hard, which is not preferable. In the high-shrinkable copolyester fiber A, when the difference in shrinkage ΔS exceeds 5%,
It is not preferable because the density and softness of the nonwoven fabric vary between nonwoven fabric production lots and the quality becomes unstable.

A second feature of the method for producing a nonwoven fabric according to the present invention resides in that a polyamide fiber B having a single yarn fineness of 2 denier or less is used as a second component. Generally, polyamide fibers are
The heat shrinkage is lower than that of the polyester fiber A in the present invention. Therefore, when the polyamide fiber is mixed with the polyester fiber, the polyamide fiber having excellent flexibility appears on the surface portion of the nonwoven fabric due to the difference in shrinkage from the polyester fiber, and a soft nonwoven fabric can be obtained. it can.

In the polyamide fiber B according to the present invention, the single yarn fineness needs to be 2 deniers or less, preferably 0.8 deniers or less. The smaller the single yarn fineness is, the more the feeling of suede-like artificial leather can be obtained. it can. If the single-fiber fineness exceeds 2 denier, the softness of the nonwoven fabric decreases, which is not preferable.

A third feature of the method for producing a nonwoven fabric of the present invention is that a high-melting polyamide polymer is used as a core component, and a low-melting polyamide polymer having a melting point lower than the melting point of each polymer constituting the fibers A and B is sheathed. The core-sheath type composite fiber C as a component (adhesive component) is used as the third component. As the core-sheath composite fiber, polyhexamethylene adipamide is used as the core component.
A core-sheath type composite fiber having a sheath component of polycapramide or copolymerized polyamide having a lower melting point than polyhexamethylene adipamide is preferred. )
UH-60 (manufactured by Unitika Ltd., trademark) and heterofil (manufactured by ICI, Inc.) as a composite fiber having a sheath component, and polyhexamethylene adipamide as a core component and copolyamide as a sheath component. Unimelt UM-60 (melting point of sheath polymer: 160 ° C., manufactured by Unitika Ltd., trademark) and Unimelt UL-60 (melting point of sheath polymer: 140 ° C., manufactured by Unitika Ltd., trademark) can be cited as the conjugated fiber. .
The type of the polymer constituting the core-sheath type composite fiber C in the present invention is appropriately selected depending on the type of the polymer constituting the polyamide fiber B. For example, when the polyamide fiber B is polyhexamethylene adipamide,
As the core-sheath type composite fiber C, any of the composite fibers exemplified above can be used. On the other hand, when the polyamide fiber B is polycapramide (melting point 220 ° C.), a fiber made of a polymer having a melting point of 215 ° C. or less, such as Unimelt UM-60 or Unimelt UL-60, is used. With the core-sheath type composite fiber C, the strength of the non-woven fabric can be improved while maintaining the flexibility of the non-woven fabric. Dimensional stability is improved.

The method for producing a nonwoven fabric according to the present invention comprises a highly shrinkable copolyester fiber A having a shrinkage ratio represented by the above formula and the formula.
And a polyamide fiber B having a single yarn fineness of 2 denier or less
And a core-sheath composite fiber having a high-melting polyamide polymer as a core component and a low-melting polyamide polymer having a melting point lower than the melting point of each polymer constituting the fibers A and B as a sheath component (adhesive component). C. to form a fiber-mixed web, and then heat-shrink the web. Prior to subjecting the fiber-mixed web to the heat shrinking treatment, a confounding treatment may be applied. In performing the confounding treatment, known methods such as a needle punch method, a water needle (span lace) method, and an air needle method can be used. When performing the heat shrinkage treatment, a dryer such as a hot air circulation dryer, a hot air once-through dryer, a suction drum dryer, a low linear pressure flat calender roll,
Using a heat treatment device such as a heat roll such as an embossing roll, a processing temperature corresponding to a target shrinkage rate, and a fiber having a lower melting point among fibers constituting the web such as a polyester fiber A or a polyamide fiber B at the highest. The treatment may be performed at a temperature equal to or lower than the melting point of the fiber and equal to or higher than the melting point of the low-melting polyamide polymer which is the sheath component of the core-sheath type composite fiber C.

In the method for producing a nonwoven fabric according to the present invention, the polyester polymer used may be copolymerized with other components other than those described above as long as the effects of the present invention are not impaired. An additive such as a colorant may be added.

In the method for producing a nonwoven fabric according to the present invention, the high-shrinkable copolyester fiber A used is prepared according to a conventional method.
After the esterification or transesterification reaction, the copolyester polymer obtained by performing the polycondensation reaction is melt-spun, and the obtained undrawn fiber yarn is drawn using a drawing roller at a temperature lower than usual. Can be manufactured.
At this time, the heat setting after the stretching is not performed, or at a low temperature even if the heat setting is performed.

In the method for producing a nonwoven fabric of the present invention, the mixing ratio (weight ratio) (A / B) of the high-shrinkable copolyester fiber A and the polyamide fiber B used is about 80/20 to 20/80. Is appropriate. The mixing ratio of the core-sheath type composite fiber C is
Mixing ratio (weight ratio) to the sum of the fibers A and B (A
+ B / C) is suitably about 95/5 to 70/30.
When these fibers are mixed, a general card method or an air lay method is used, but a wet papermaking method may be used depending on the purpose.

(Function) The nonwoven fabric obtained by the production method of the present invention has a dense and soft feel and high strength. This is because the highly shrinkable copolyester fiber A shrinks during the heat shrink treatment to express denseness, and the polyamide fiber B, which has excellent flexibility due to the difference in shrinkage from the copolyester fiber A, forms a nonwoven fabric. This is because the core-in-sheath type composite fiber C which appears on the surface portion of the nonwoven fabric and has excellent flexibility adheres between the constituent fibers of the nonwoven fabric to exhibit high strength.

(Example) Next, the present invention will be specifically described based on examples.
Various characteristics in the examples were measured by the following methods.

Relative viscosity: The relative viscosity was measured at a sample concentration of 0.5 g / dl and a temperature of 20 ° C. using an equal weight mixed solution of phenol and ethane tetrachloride as a solvent.

Strength: The nonwoven fabric was cut to a width of 25 mm, and measured at a sample length of 100 mm and a tensile speed of 100 mm / min using a constant-speed extension type tensile tester.

Bending resistance: Measured by the JIS L 1096 45 degree cantilever method.

Hand: A sensory test with 10 panelists evaluated the following five levels.

1: Soft, 2: Slightly soft, 3: Normal, 4: Slightly hard, 5: Hard Dry heat shrinkage ratio So: Dry the fiber of length Lo within 1 day immediately after production at 170 ° C for 15 minutes. And then cooled to room temperature. The length L ₁ of the sample after cooling was measured to determine shrinkage So according to the following equation.

Dry heat shrinkage difference ΔS: Immediately after the production, the fiber having a length of L ₀ ′ after standing at a temperature of 40 ° C. for 5 weeks was heated at 170 ° C. for 15 minutes using a dryer, and then cooled to room temperature. The length L ₁ ′ of the cooled sample was measured, the shrinkage ratio S ₀ ′ was obtained according to the following equation, and the difference in shrinkage ΔS was obtained according to the equation.

Areal shrinkage SA: the area A ₁ of the post-treatment with heat shrinking treatment before the area Ao of the nonwoven fabric was measured to determine shrinkage SA according to the following equation.

Example 1 A copolymerized polyester polymer comprising terephthalic acid / isophthalic acid and ethylene glycol at a molar ratio of 92/8 and having a relative viscosity of 1.45 was produced by a conventional method, melt-spun, and then subjected to a first heating at 65 ° C. The stretched fiber is stretched between the stretching roller and the second stretching roller at a temperature of 75 ° C. at a stretching ratio of 3.0, and the stretched fiber is cut without heat setting to obtain a single yarn fineness of 1.3 denier and a cut elongation of 49.
%, A short polyester fiber A having a fiber length of 51 mm. The shrinkage ratio So of this short fiber is 62.5%, and the difference ΔS in shrinkage ratio is 2.
1%.

On the other hand, according to a conventional method, polycapamide short fiber B having a single yarn fineness of 0.8 denier and a fiber length of 38 mm was produced.

Next, a polyamide-based composite short fiber Unimelt UL-60 (having a melting point of the sheath polymer) having the core component of the copolyester staple fiber A, the polycapramide staple fiber B, and the polyhexamethylene adipamide as the core component and the copolyamide as the sheath component. 140 ° C, single fiber fineness 2 denier, fiber length 51mm, manufactured by Unitika Ltd.
And cotton mixing trademark) C mixing ratio (weight ratio) with (A / B / C) 30/60/10 , after a having a basis weight of 175 g / m ² web through the card,
Needle punching was performed, and heat treatment was performed for 2 minutes with a suction drum type heat treatment machine at a temperature of 160 ° C. to obtain a nonwoven fabric. Table 1 shows the properties of the obtained nonwoven fabric.

This nonwoven fabric had a dense structure, a soft touch, and a high strength.

Examples 2 to 4 Nonwoven fabrics were obtained in the same manner as in Example 1 except that the molar ratio of terephthalic acid / isophthalic acid was changed to 96/4, 93/7 and 88/12. Table 1 shows the properties of the obtained nonwoven fabric.

Comparative Examples 1 and 2 The molar ratio of terephthalic acid / isophthalic acid was 97/3 and 85/1
A nonwoven fabric was obtained in the same manner as in Example 1 except that the sample was set to 5. Table 1 shows the properties of the obtained nonwoven fabric.

In Comparative Example 1, the copolyester staple fiber A had a low shrinkage So, and the obtained nonwoven fabric lacked denseness. In addition, the difference ΔS in the shrinkage of the fibers is high, and the density and flexibility of the nonwoven fabric are varied between the lots for manufacturing the nonwoven fabric, resulting in unstable quality.

In Comparative Example 2, since the shrinkage rate So of the copolyester short fiber A was high, the obtained nonwoven fabric was too dense and had high rigidity and softness. Partial fusion occurred and had a hard touch.

Examples 5 to 7 The single fiber fineness of the polycapramid short fibers B was 0.5, 1.2 and 2.0.
A nonwoven fabric was obtained in the same manner as in Example 1 except that denier was used. Table 1 shows the properties of the obtained nonwoven fabric.

Comparative Example 3 A nonwoven fabric was obtained in the same manner as in Example 1 except that the single fiber fineness of the polycapramide short fiber B was changed to 3.0 denier. Table 1 shows the properties of the obtained nonwoven fabric.

When the single fiber fineness of the polycapramid short fiber B exceeded 2.0 denier, the obtained nonwoven fabric had a low area shrinkage, lacked denseness, had high rigidity and softness, and had a hard touch.

Examples 8 to 10 and Comparative Example 4 Copolyester staple fiber A, polycapramide staple fiber B
A nonwoven fabric was obtained in the same manner as in Example 1 except that the mixing ratio (weight ratio) (A / B / C) of the polyamide-based composite short fiber Unimelt UL-60, C was changed as shown in Table 2. . Table 2 shows the properties of the obtained nonwoven fabric.

In Comparative Example 4, since the polyamide-based composite short fiber C was not mixed, the obtained nonwoven fabric had low strength, and when the nonwoven fabric was used as a base fabric of synthetic leather or artificial leather,
The dimensional stability when the final product was pulled was insufficient.

(Effect of the Invention) According to the method for producing a nonwoven fabric of the present invention, when used as a base fabric of synthetic leather or artificial leather, a dense and soft feeling and high strength are exhibited, and when the final product is pulled, A fiber-mixed nonwoven fabric which has excellent dimensional stability and can be suitably used for the above-mentioned applications can be easily produced.

Claims (2)

(57) [Claims] (1) having a shrinkage ratio represented by the following and formula,
Highly shrinkable copolyester fiber A comprising an acid component having a molar ratio of terephthalic acid / dicarboxylic acid other than terephthalic acid of 96/4 to 88/12 and an ethylene glycol component, and a polyamide having a single yarn fineness of 2 denier or less Core-sheath comprising a base fiber B and a high-melting polyamide polymer as a core component, and a low-melting polyamide polymer having a melting point lower than the melting point of each polymer constituting the fibers A and B as a sheath component (adhesive component). Type composite fiber C
A heat-shrinkage treatment on the fiber-mixed web mixed with the non-woven fabric. 25 ≦ S ₀ (%) ≦ 70 ΔS (%) ≦ 5 [S ₀ (%) is the shrinkage when the fiber immediately after production is subjected to dry heat treatment at 170 ° C. for 15 minutes, and ΔS (% ) Is the difference between the shrinkage ratio and the shrinkage ratio S ₀ (%) when the fiber immediately after production is left at a temperature of 40 ° C. for 5 weeks and then subjected to a dry heat treatment at a temperature of 170 ° C. for 15 minutes. ] 2. It has a shrinkage ratio represented by the following and formula,
Highly shrinkable copolyester fiber A comprising a diol component having a molar ratio of ethylene glycol / diol other than ethylene glycol of 96/4 to 88/12 and a terephthalic acid component
And a polyamide fiber B having a single yarn fineness of 2 denier or less.
And a core-sheath type conjugate fiber having a high-melting polyamide polymer as a core component and a low-melting polyamide polymer having a lower melting point than the melting point of each of the polymers constituting the fibers A and B as a sheath component (adhesive component). A method for producing a fiber-mixed nonwoven fabric, comprising subjecting a fiber-mixed web mixed with C to a heat shrink treatment. 25 ≦ S ₀ (%) ≦ 70 ΔS (%) ≦ 5 [S ₀ (%) is the shrinkage when the fiber immediately after production is subjected to dry heat treatment at 170 ° C. for 15 minutes, and ΔS (% ) Is the difference between the shrinkage ratio and the shrinkage ratio S ₀ (%) when the fiber immediately after production is left at a temperature of 40 ° C. for 5 weeks and then subjected to a dry heat treatment at a temperature of 170 ° C. for 15 minutes. ]