JPH0726310B2 - Extra-fine long-fiber non-woven fabric - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-woven fabric made of ultrafine long fibers, and more particularly to a nonwoven fabric made of ultrafine long fibers having a delicate surface morphology.

(Prior Art) Nonwoven fabrics have been conventionally used for various purposes such as clothing, industrial materials, civil engineering and construction materials, agricultural and horticultural materials, life-related materials, medical hygiene materials, and the like. Among them, non-woven fabrics made of long fibers are widely used because they have higher strength and higher productivity than non-woven fabrics made of short fibers. Many attempts have been made to obtain a non-woven fabric having a delicate structure on the non-woven fabric made of long fibers. For example, JP-B-44-24699 and JP-B-52-30629
In Japanese Patent Publication No. 62-41316 and Japanese Patent Publication No. 62-41316, a non-woven fabric made of fine fibers by subjecting a sheet to chemical treatment to dissolve or partially dissolve a polymer constituting the fibers. Is disclosed.
In addition, Japanese Patent Publication Nos. 1-47585 and 1-47586 disclose a non-woven fabric obtained by treating a sheet with a high-pressure water stream to split the fibers into ultrafine fibers and subjecting the fibers to three-dimensional entanglement. Japanese Patent Publication No. 1-47579 discloses that
It is disclosed that a nonwoven fabric made of ultrafine fibers is obtained by washing the nonwoven fabric with water to remove water-soluble components.
However, these non-woven fabrics or non-woven fabric production methods have a problem in that the production process is complicated and the polymer needs to be removed, resulting in high production cost. Furthermore, Japanese Patent Publication No. 53-10169 discloses that a nonwoven fabric composed of ultrafine fibers is obtained by buffing a sheet and splitting the fibers. There is a problem that it will be damaged.

(Problems to be Solved by the Invention) The present invention intends to solve the above problems and provide a nonwoven fabric made of ultrafine long fibers having a delicate surface morphology.

(Means for Solving the Problem) The inventor of the present invention has reached the present invention as a result of extensive studies to solve the above problems. That is, the present invention relates to the polymer component A
And a bicomponent composite filament comprising a polymer component B which is incompatible with the polymer component A and having two or more convex lens-shaped cross sections, and A two-component composite continuous fiber in which a segment composed of a united component B is partly peeled off, a split fiber composed of only the polymer component A developed by the division of the two-component composite continuous fiber, and the polymer component B. A non-woven fabric composed of split filaments having a single yarn fineness of 0.8 denier or less, wherein the melting point difference between the polymer component A and the polymer component B is 30 ° C. or more, 2 Radius of the circumscribed circle of the polymer component A in the cross section perpendicular to the fiber axis of the component composite long fiber
R ₀ , radius R ₁ of the circumscribed circle of the polymer component B, radius of curvature R _{2 of} an arc in contact with the polymer component A in the convex lens-shaped portion composed of the polymer component B, arc length L of the arc and convex lens-shaped portion The thickness H satisfies the following and the formula, and the splitting ratio of the segment composed of the polymer component B is 30% or more and 95% or less,
An ultrafine long-fiber non-woven fabric, characterized in that the fibers are at least partially adhered to each other by fibers made of a polymer component having a lower melting point of either the polymer component A or the polymer component B. It is a thing.

R ₁ / R ₀ > 1 ...... R ₂ / R ₀ ≧ 1 ...... L / H ≧ 1 ...... Next, the present invention will be described in detail.

The incompatible polymer components A and B in the present invention each have a fiber-forming ability and can be melt-spun by using an ordinary melt-spinning apparatus. Polymer component A
Examples of the combination of B and B include polyester-based and polyamide-based, polyester-based and polyolefin-based, polyamide-based and polyolefin-based, and the like, and polyester-based polymers include polyesters such as polyethylene terephthalate and polybutylene terephthalate. Examples of the system include polyamides such as nylon 6, nylon 46, nylon 66, and nylon 610, and examples of the polyolefin system include polypropylene, high-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer, and other polyolefins. Further, to the polymer components A and B, an additive such as a usual matting agent, heat stabilizer, pigment or polymer crystallization accelerator may be added.

The ultrafine long-fiber non-woven fabric of the present invention is obtained by collecting melt-spun two-component composite long fibers by an air sucker, depositing them on a collecting surface such as a web conveyor, and by using an embossing roll, the polymer component A or the polymer component. Non-woven fabric obtained by heat-treating at a temperature lower than the melting point of the polymer component on the low melting point side of B to bond the fibers at least partially with the fiber composed of the polymer component on the low melting point side. It can be prepared by peeling the fiber composed of the polymer component B from the composite long fiber by bending the web or by treating with a group of rolls having a high linear pressure which is heated or not heated and has a smooth surface. Further, the fibers made of the polymer component B are separated from the composite long fibers by treating the web with a group of rolls having a high linear pressure and having a smooth surface, and at the same time, by the fibers made of the polymer component on the low melting point side. It can be made by at least partially bonding the fibers. Further, the web is treated with a group of rolls having a high linear pressure and not heated and having a smooth surface, and the fibers composed of the polymer component B are once separated from the composite long fibers to obtain split filaments, and then the above-mentioned low roll is applied with a heating roll. It can also be prepared by at least partially adhering the fibers with a fiber composed of a polymer component on the melting point side. The obtained non-woven fabric may be subjected to softening for improving the softness of the non-woven fabric.

The melting point difference between the polymer component A and the polymer component B in the present invention needs to be 30 ° C. or higher. The melting point of the polymer in the present invention means the differential calorimeter DSC-
Type 2 is used, and the sample volume is reduced according to the manual of the device.
It was obtained from a DSC curve obtained by measuring at 5 mg and a scanning speed of 20 ° C / min. Polymer component A and polymer component B
If the melting point difference with the temperature is less than 30 ℃, when the web is heat-bonded with a heating roll, the non-woven fabric heat-shrinks and the dimensional stability deteriorates, and the texture of the non-woven fabric deteriorates. Is narrowed, which causes problems such as difficulty in temperature control, which is not preferable. When the web is heat-bonded with a heating roll having a surface temperature higher than the melting point of the polymer component on the low melting point side, the obtained nonwoven fabric becomes a film or has a hard surface, which is not preferable.

For web formation, highly oriented unstretched long fibers obtained by a so-called high-speed spinning method, in which melt-spun fiber bundles are cooled and then drawn from an air blower, are used as a continuous process from spinning to web formation. The web can be prepared by taking long fibers with an air sucker, forcibly charging them with a charging device to open the fibers, and depositing them on a collecting surface such as a moving web conveyor.

Next, the two-component composite continuous fiber in the present invention will be described.

1 and 2 are cross-sectional views for explaining the structure of the bicomponent composite continuous fiber in the present invention, and FIGS. 3 and 4 show examples of the bicomponent composite continuous fiber satisfying the constituent requirements of the present invention. FIG. In Figures 1 and 2, R ₀ is the radius of the circumscribed circle of the polymer component A in the cross section perpendicular to the fiber axis of the bicomponent composite filament, R ₁ is the radius of the circumscribed circle of the polymer component B, and R ₂ is In the convex lens-shaped portion composed of the polymer component B, the polymer component A
Is the radius of curvature of an arc in contact with, L is the arc length of the arc, and H is the thickness of the convex lens-like portion. R ₀ , R ₁ , R ₂ , L and H are obtained by actual measurement based on a cross-sectional photograph taken by enlarging the fiber cross section 1000 times.

The ultra-fine long-fiber nonwoven fabric of the present invention is shown in FIGS.
It is necessary that R ₀ , R ₁ , R ₂ , L and H satisfy the above and the formula. If R ₁ / R ₀ is R ₁ / R ₀ ≦ 1, or R ₂
When / R ₀ is R ₂ / R ₀ <1, the polymer component A and the polymer component B are
When peeling, the polymer component A and the polymer component B are difficult to peel and split unless it is treated with a roll group having an extremely high linear pressure and a smooth surface, which is not preferable. R ₁
Even if / R ₀ is R ₁ / R ₀ ＞ 1, and R ₂ / R ₀ is R ₂ / R ₀ ≧ 1, L / H is
When L / H <1, depending on the selection of the polymer component A and the polymer component B, the polymer component A and the polymer component B are separated from each other in the process of drawing the two-component composite long fiber yarn by air sucker. When the material is made into a web, the spreadability of the fibers is deteriorated and a uniform web cannot be obtained, which is not preferable.

The ultrafine long-fiber nonwoven fabric of the present invention is one in which the segment made of the polymer component B has a split fiber ratio of 30% or more and 95% or less.
This splitting ratio is defined as a two-component composite continuous fiber in which R ₀ , R ₁ , R ₂ , L and H satisfy the above and the formula, and a segment composed of the two-component composite continuous fiber and a polymer component B. Part-peeled bicomponent composite filaments, split filaments composed only of the polymer component A developed by division of the bicomponent composite filaments, and single yarn fineness composed only of the polymer component B. Of the non-woven fabric composed of split continuous filaments of 0.8 denier or less, the cross section of the non-woven fabric is magnified 100 times and a cross-sectional photograph is taken.
It is calculated by calculating the total number of segments of the polymer component B peeled from the composite long fiber and the total number of segments of the polymer component B that are present, and the weight of the peeled weight relative to the total number of segments of the polymer component B that is present. It represents the ratio (%) of the total number of segments of the combined component B.

The extra-fine long-fiber nonwoven fabric of the present invention has the split fiber ratio of 30% or more.
If the splitting ratio is less than 30%, it is not possible to obtain a non-woven fabric having a delicate surface morphology.

Further, the split filaments composed only of the polymer component B developed by the division of the composite filaments have a single yarn fineness of 0.
It is less than 8 denier. Even if the splitting ratio is 30% or more, it becomes difficult to obtain a non-woven fabric having a delicate surface morphology if the single yarn fineness of the split continuous fibers made of the polymer component B exceeds 0.8 denier. As the yarn fineness is smaller, a nonwoven fabric having a finer surface morphology can be obtained.

In the two-component composite continuous fiber of the present invention, the number of segments of the polymer component B having a convex lens-like cross section needs to be two or more. When the number of this segment is one, the composite long fibers are crimped depending on the spinning conditions, and when the fibers are made into webs, the fiber openability is deteriorated and uniform webs cannot be obtained.

In the present invention, by selecting various kinds of polymers to be combined, polymer composite ratios, spinning conditions, splitting and splitting conditions, adhesion conditions, and post-processing conditions such as softening, it is possible to obtain ultrafine long fibers according to the purpose of use. A fibrous nonwoven fabric can be obtained.

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

Intrinsic viscosity: Equal weight mixture of phenol and ethane tetrachloride was used as solvent, and measured at 20 ℃.

Melt Index: Measured by the ASTM D1238E method.

Melting point: It was determined from a DSC curve obtained by using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. and measuring the sample amount at about 5 mg at a scanning rate of 20 ° C./min.

Non-woven fabric vertical and horizontal tensile strength: width 3 cm, length
A 10 cm measurement sample piece was prepared and measured by the strip method described in JIS L-1096.

Total hand: The total hand is an index showing the flexibility of the cloth, and was measured by the handle odometer method described in JIS L-1096 with a slot width of 10 mm.

Example 1 A composite polymer having a melting point of 128 ° C. and a melt index value of 25 g / 10 min as a polymer component A, a polyethylene terephthalate polymer having a melting point of 258 ° C. and an intrinsic viscosity of 0.70 as a polymer component B, and composite spinning The two-component composite continuous fiber was melt spun through a spinneret having 200 holes. At the time of melt spinning, the melting temperature of the polymer component A was 230 ° C, and the single hole discharge rate was 0.60 g /
Min, the melting temperature of polymer component B is 285 ° C, and the single-hole discharge rate is 0.6
It was 0 g / min [the ratio (weight ratio) of component A and component B was 1: 1]. After cooling the spun filament yarn, the spinneret bottom 12
Twenty-five filaments are sucked into each of eight air-suckers arranged at a position of 0 cm, and sucked at a speed of 3500 m / min.
The fibers were forcibly charged by a charging device to open the fibers, and the fibers were deposited on the moving web conveyor surface to obtain a web.

As shown in FIG. 3, the cross-sectional shape of the obtained two-component composite continuous fiber is composed of polymer component A and polymer component B.
And a segment having a convex lens-shaped cross section. R ₀ , R ₁ , R ₂ , L and H were calculated based on the cross-sectional photograph taken by enlarging the fiber cross section 1000 times, and R ₁ / R ₀ , R ₂ /
When R ₀ and L / H are calculated, R ₁ / R ₀ is 1.4, R ₂ / R ₀ is 6.3, L /
H was 2.5. The composite long fibers were not split and the web was uniform.

Next, a nonwoven fabric was obtained by subjecting the obtained web to splitting and heat-bonding treatment twice using a heated roll group having a smooth surface. This treatment condition is such that the surface temperature of the heating rolls is 115
℃, the line pressure was 100kg / cm.

The obtained non-woven fabric had a basis weight of 50 g / m ² , a tensile strength in the vertical direction of 5.2 kg / 3 cm, a tensile strength in the horizontal direction of 3.8 kg / 3 cm, and a total hand of 200 g. Select any 10 points on the non-woven fabric, magnify the cross-section of the non-woven fabric 100 times, and take a cross-sectional photograph. Then, in the 10 cross-sectional photographs, the total number of segments of polymer component B peeled from the composite long fiber and When the total number of segments of the polymer component B present was determined and the splitting ratio was determined, the splitting ratio was 80%. Further, the fineness of the split filaments composed of only the polymer component B developed by the division of the composite filaments was determined to be 0.31 denier, which was extremely thin.

The non-woven fabric had a delicate surface morphology.

Comparative Example 1 A splittable bicomponent composite filament was melt-spun in the same manner as in Example 1 except that a polyethylene polymer having a melting point of 132 ° C. and a melt index value of 15 g / 10 min was used as the polymer component A. After cooling, it was sucked through a filament through an air filter, drawn at a speed of 3500 m / min, forcibly charged by a charging device to open the fibers, and deposited on the moving web conveyor surface to obtain a web.

As shown in FIG. 5, the cross-sectional shape of the obtained bicomponent composite continuous fiber is composed of polymer component A and polymer component B.
And a segment having a convex lens-shaped cross section. R ₀ based on cross-sectional photograph of the fiber cross section, obtains the R _1, R _2, L and H, was calculated _{R 1 / R 0, R 2} / R 0 and _{L / H, R 1 / R} 0 Was 2.0, R ₂ / R ₀ was 6.5, and L / H was 0.7. In addition, the composite long fibers were partially split, and the openability of the fibers was partially defective, and the web lacked uniformity.

Next, in the same manner as in Example 1, the obtained web was subjected to splitting and heat-bonding treatment twice using a heated roll having a smooth surface to obtain a nonwoven fabric.

The non-woven fabric obtained had a high splitting ratio of 90% and had a delicate surface morphology, but lacked uniformity.

Example 2 The web obtained in Example 1 was embossed using a heated embossing roll having a pressing area ratio of 12% to obtain a nonwoven sheet. The processing conditions were that the surface temperature of the heated embossing roll was 120 ° C and the linear pressure was 30 kg / cm.

Next, the obtained non-woven sheet was subjected to bending wrinkle processing.

The obtained nonwoven fabric had a basis weight of 60 g / m ² , a tensile strength in the vertical direction of 12.6 kg / 3 cm, a tensile strength in the horizontal direction of 5.0 kg / 3 cm, and a total hand of 65 g. When 10 parts of the non-woven fabric were selected and the percent score was calculated, the percent score was 95%. Further, the fineness of the split filaments composed of only the polymer component B developed by the division of the composite filaments was determined to be 0.31 denier, which was extremely thin. And this non-woven fabric had a drape property and a delicate surface morphology.

(Effect of the Invention) The ultrafine long-fiber nonwoven fabric of the present invention comprises a two-component composite continuous fiber composed of a polymer component A and a polymer component B, and a segment composed of the two-component composite continuous fiber and the polymer component B. Partially separated two-component composite continuous fiber, split filament long fiber composed only of polymer component A developed by division of the two-component composite continuous fiber, and single yarn fineness composed only of the polymer component B. Is composed of split filaments of 0.8 denier or less and has excellent strength, extremely high uniformity, and delicate surface morphology, so it can be suitably used as a material for medical hygiene materials. .

The ultrafine long-fiber nonwoven fabric of the present invention can be efficiently produced at low cost without requiring a complicated production process as in the past.

[Brief description of drawings]

1 and 2 are cross-sectional views for explaining the structure of the bicomponent composite continuous fiber in the present invention, and FIGS. 3 and 4 show examples of the bicomponent composite continuous fiber satisfying the constituent requirements of the present invention. Cross-sectional views, FIGS. 5 and 6, are cross-sectional views showing examples of bicomponent composite filaments that do not satisfy the constituent requirements of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Matsuoka 23, Uji Kozakura, Uji City, Kyoto Prefecture Noriyoshi Kikuchi Examiner, Central Research Laboratory, Unitika Ltd.

Claims (1)

[Claims] 1. A bicomponent composite continuous fiber comprising a polymer component A and a segment having two or more convex lens-shaped cross sections, which is composed of a polymer component B which is incompatible with the polymer component A. A split fiber composed only of a two-component composite continuous fiber in which a segment composed of a polymer component B is partly peeled from the two-component composite continuous fiber and the polymer component A developed by the division of the two-component composite continuous fiber. A melting point of the polymer component A and a melting point of the polymer component B, which is a non-woven fabric composed of long fibers and split filaments having a single yarn fineness of 0.8 denier or less, which is composed only of the polymer component B. Radius R ₀ of the circumscribed circle of the polymer component A, radius R ₁ of the circumscribed circle of the polymer component B, and polymer component B in the cross section perpendicular to the fiber axis of the bicomponent composite filament with a difference of 30 ° C or more. Is in contact with the polymer component A in the convex lens-like portion consisting of The radius of curvature R ₂ of the circular arc, the thickness H of the arc length L and the convex lens shaped portion of the arc below, and satisfies the equation, split fiber proportion of segments of the polymer component B is 95% or less than 30% Moreover, the polymer component A is present between the fibers.
Alternatively, the ultrafine long-fiber nonwoven fabric is characterized in that it is at least partially adhered by a fiber composed of the polymer component on the low melting point side of the polymer component B. R ₁ / R ₀ ＞ 1 …… R ₂ / R ₀ ≧ 1 …… L / H ≧ 1 ……