JPH08291450A - Bulky nonwoven fabric having water absorbing property and its production - Google Patents

Abstract

PURPOSE: To obtain the subject soft nonwoven fabric having stiffness and useful for wet tissue, etc., by mixing a crimpable synthetic fiber in which three- dimensional crimps develop with a hydrophilic fiber in interlacing state. CONSTITUTION: This nonwoven fabric is obtained by interlacing fibers by carrying out high pressure water flow treatment of a fiber web containing (A) 20-50wt.% crimpable synthetic fiber in which three-dimensional crimps develop and (B) 80-50wt.% hydrophilic fiber. In the case of synthetic fiber crimpable in the production process of the fiber, nonwoven fabric having low weight, e.g. wet tissue can readily be produced.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-absorbent bulky nonwoven fabric suitable for wet tissues, wipers and the like.

[0002]

2. Description of the Related Art Generally, paper and non-woven fabrics used for wet tissues, wipers, etc. can withstand the force applied during wiping, or the force applied during pulling out when used in a pop-up system. Powerfulness is needed. At the same time, water absorption that can retain detergent and wiped water is also required. Therefore, non-woven fabrics for wet tissues and wipers are prepared by mixing water-absorbent fibers such as rayon and cotton with heat-adhesive composite fibers made of a combination of polyester / polyethylene or polypropylene / polyethylene and adhering the fibers together by heat. , Has given the power.

[0003]

On the other hand, since wet tissues and wipers are touched by human hands, it is necessary to consider the goodness and badness of touch as one of the basic performances as well as the strength and water absorption. However, in reality, what is commercially available only satisfies the required performance for strength and water absorption, and the touch is not taken into consideration.

Generally, the tactile sensation demanded by consumers is that it is fluffy and soft when it touches the skin, and that it feels firm during a wiping operation. In other words, what is bulky, soft and firm is desired.

The present invention has been made for the purpose of obtaining a nonwoven fabric satisfying these requirements, and has achieved the purpose by using a specific synthetic fiber.

[0006]

Means for Solving the Problems That is, the present invention provides a nonwoven fabric in which 20 to 50% by weight of crimpable synthetic fibers and 80 to 50% by weight of hydrophilic fibers are contained, and the fibers are entangled with each other. A bulky non-woven fabric characterized by three-dimensional crimps in crimpable synthetic fibers, and crimpable synthetic fibers 20 to 5 in which a heat-adhesive component occupies at least a part of the fiber surface.
In a non-woven fabric containing 0% by weight and 80 to 50% by weight of hydrophilic fibers, the fibers are entangled with each other, and the fibers are heat-bonded at the points where the fibers contact each other, and the crimpable synthetic fiber. In three-dimensional crimps, the present invention relates to a bulky non-woven fabric. The contents will be described below.

The crimpable synthetic fiber used in the present invention is preferably an actual crimpable synthetic fiber. Here, "having an actual crimp property" means a fiber that develops a three-dimensional crimp in the process of producing a fiber and cannot develop a three-dimensional crimp in the state of being made into a fibrous web or nonwoven fabric. Further, as shown in FIGS. 1 to 3, the three-dimensional crimp is not limited to a spiral crimp, but is one that bends in a two-dimensional direction with a gentle curve or a two-dimensional bend. It refers to crimps in a different form from mechanical crimps such as twisted ones. By using this fiber, it becomes possible to impart bulkiness to the nonwoven fabric. In addition, when the crimpable synthetic fibers are used, the crimp does not appear at the stage of manufacturing the nonwoven fabric and the size of the nonwoven fabric does not decrease, which facilitates the process control in the production of the low-density nonwoven fabric such as a wet tissue. There are advantages.

Further, in the present invention, it is desirable that the synthetic fiber has a heat-adhesive property and can bond the fibers as a heat-adhesive fiber. This is to give strength to the non-woven fabric. Of course, from the viewpoint of imparting strength to the non-woven fabric, it is possible to separately prepare the heat-bondable synthetic fibers and the heat-bondable fibers and heat-bond them, but in that case, the heat-bondable fibers are Since the three-dimensional crimp developed in the crimpable synthetic fiber is melted in such a manner as to fix the three-dimensional crimp, the degree of freedom of the three-dimensional crimp is remarkably diminished and the tactile sensation deteriorates.

The crimpable synthetic fiber is specifically a composite fiber composed of two or more polymers having different heat shrinkages, and at least a part of the fiber surface is occupied by the heat adhesive component. You can use what you have. A polymer having a melting point in the range of 120 to 170 ° C. may be used as the heat-adhesive component. For example, homopolymers such as high-density polyethylene, medium-density polyethylene, low-density polyethylene and polypropylene, or copolymers thereof are applicable.

The polymer to be combined with these heat-adhesive polymers may be one having a higher melting point than the polymer exhibiting heat-adhesive properties, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, nylon and polypropylene. Specific polymer combinations include ethylene-propylene random copolymer / polypropylene, high-density polyethylene / polybutylene terephthalate, high-density polyethylene / polyethylene terephthalate, modified polyester / polyethylene terephthalate, and the like.

The polymer is preferably arranged such that the thermal adhesive component occupies at least a portion of the fiber surface.
Specific examples thereof include an eccentric core-sheath structure as shown in FIG. 4 using a heat-adhesive polymer as a sheath component, or a side-by-side type joint of two kinds of polymers as shown in FIG. .

In the present invention, the former is composed of high density polyethylene and polyethylene terephthalate, and the former is a sheath component,
It is most preferable to use an eccentric core / sheath type composite fiber having the latter as a core component. This is because polyethylene terephthalate has an appropriate rigidity, so that it is possible to impart "stiffness" to the entire nonwoven fabric even in a wet state. In addition, when high-density polyethylene and polyethylene terephthalate are combined, the temperature at which three-dimensional crimps develop is lower than the melting point of high-density polyethylene, so it is an optimum combination.

The crimpable synthetic fiber can exhibit a desired three-dimensional crimp by adjusting the polymer composite ratio and arrangement, spinning conditions, drawing conditions, heating conditions and the like.
In the present invention, it is desirable that 14 to 20 three-dimensional crimps are developed per inch. This is because if the number is less than 14, the bulk of the nonwoven fabric cannot be sufficiently increased, and if the number is more than 20, the card passing property is deteriorated, and it becomes difficult to obtain a uniform nonwoven fabric.

The nonwoven fabric of the present invention preferably contains 20 to 50% by weight of the crimpable synthetic fiber. Two
This is because if it is less than 0% by weight, the bulk of the nonwoven fabric cannot be sufficiently increased, and if it exceeds 50% by weight, the proportion of the hydrophilic fibers is decreased and the water absorption capacity becomes insufficient.

In the present invention, the hydrophilic fiber is used for imparting water absorbency to the nonwoven fabric. Therefore, the type is not particularly limited, and natural fibers such as cotton or regenerated fibers such as rayon and cupra can be used. Particularly in the present invention, the use of rayon is most preferable because staple fibers having a certain length are easily available.

The proportion of hydrophilic fibers is preferably 80 to 50% by weight. If it exceeds 80% by weight, the proportion of the crimpable synthetic fibers becomes small, so that a bulky nonwoven fabric cannot be obtained and the strength becomes small. If it is less than 50% by weight, the water absorption capacity will be insufficient.

The fineness and fiber length of both the crimpable synthetic fiber and the hydrophilic fiber described above can be arbitrarily selected according to the nonwoven fabric to be finally obtained. Considering handleability in the manufacturing process, it is desirable that the fineness is 2 to 6 denier and the fiber length is 38 to 64 mm.

The nonwoven fabric of the present invention is characterized in that the specific crimpable synthetic fibers in which three-dimensional crimps have been developed are mixed with hydrophilic fibers, and the fibers are entangled with each other. More preferably, they are heat bonded at the points where they contact each other. The configuration will be described below together with the manufacturing method.

The fibers can be entangled by needle punching or high-pressure water stream treatment. In the present invention, in order to improve the drape property of the nonwoven fabric, it is desirable that the fibers are entangled with each other by high-pressure water flow treatment.

In the entanglement, it is necessary to previously mix the crimpable synthetic fiber and the hydrophilic fiber into a fibrous web.
The form of the web is not particularly limited, and may be a parallel web, a cross web, a semi-random web, a random web, or the like. The basis weight of the web can be arbitrarily determined according to the intended use of the nonwoven fabric to be finally obtained. For example, when used as a wet tissue, 30 to 50 g / m ² is preferable.

In treating the high-pressure water stream, a generally well-known method can be arbitrarily adopted, and the conditions may be set according to the basis weight and the like. For example, basis weight 40g / m
^When high pressure columnar water flow treatment is applied to about ² fiber webs, an orifice with a hole diameter of 0.01 to 0.5 mm is 0.1 to 1.5 mm.
A columnar water flow having a water pressure of 20 to 80 kg / cm ² may be jetted from the front and back surfaces 1 to 4 times from nozzles provided at intervals.

After the high-pressure water stream treatment, a heat treatment is carried out to melt the heat-adhesive component of the latent crimpable component and heat-bond them at the points where the fibers come into contact with each other, whereby a stronger nonwoven fabric can be obtained. The heat treatment is preferably performed at a temperature higher than the melting point of the heat-adhesive component, and is preferably performed using a hot-air penetrating dryer so as not to impair the bulkiness of the nonwoven fabric.

[0023]

The crimpable synthetic fiber used in the present invention develops a three-dimensional crimp in the fiber production stage, and this three-dimensional crimp contributes to the improvement of the bulkiness of the nonwoven fabric. Further, if at least a part of the fiber surface of the crimpable synthetic fiber is composed of a heat-adhesive component, the fibers can be adhered to each other by heat treatment, and thus the nonwoven fabric also has a function of imparting strength. The hydrophilic fiber ensures water absorption, which is a basic required performance of wet tissues and wipers.

The non-woven fabric of the present invention is obtained by subjecting the fibrous web to a high-pressure water stream treatment or the like in advance to intimately entangle the fibers. Due to the entanglement between the fibers, the nonwoven fabric finally obtained becomes “stiff”. Further heat treatment,
The strength of the non-woven fabric is further improved by thermally adhering the fibers at the points where they contact each other.

[0025]

The present invention will be described below with reference to examples. [Manufacture of Crimped Fiber A] Melting-spun at a spinning temperature of 300 ° C. using a polyester having a melting point of 260 ° C. as a core component and a high-density polyethylene having a melting point of 130 ° C. as a sheath component, and an eccentric core-sheath as shown in FIG. A type composite fiber was obtained. Then 70
It was stretched 3.5 times in warm water at 0 ° C, and 15 mechanical crimps per inch were applied by a stuffing box while applying a fiber oil agent. Then, using a hot air dryer, 1
After being dried at 10 ° C. to develop a three-dimensional crimp, it was cut to obtain a staple fiber having a fineness of 2 denier and a fiber length of 51 mm. This fiber exhibited 16 three-dimensional crimps per inch as shown in FIG.

[Production of Fiber B] Using the resin used in the production of the fiber A, in the same manner as the fiber A, the core / sheath of polyester / high density polyethylene has a fineness of 2 denier and a fiber length of 51.
mm staple-fiber of concentric core-sheath type composite fiber was manufactured. This fiber did not develop a three-dimensional crimp even when heated, and kept the shape of a mechanical crimp.

Example 1 30% by weight of fiber A and 70% by weight of rayon having a fineness of 1.5 denier and a fiber length of 40 mm.
And were mixed and a parallel web was created with a parallel card. A high-pressure water stream having a water pressure of 30 kg / cm ² was jetted twice from the front surface and once from the back surface from nozzles provided with orifices having a hole diameter of 0.13 mm at intervals of 1 mm to entangle the fibers. Next, this was heated at 70 ° C. using a hot-air penetrating dryer to dry the nonwoven fabric without thermally adhering the fibers to each other.

[Examples 2 to 4] Fiber A and rayon having a fineness of 1.5 denier and a fiber length of 40 mm were mixed at the ratio shown in Table 1 to prepare a parallel web with a parallel card. This was subjected to a high-pressure water stream treatment in the same manner as in Example 1 to entangle the fibers and then heated at 135 ° C. using a hot air penetrating dryer to thermally bond the points where the fibers contact each other.

[Comparative Example 1] 30% by weight of fiber B and 70% by weight of rayon having a fineness of 1.5 denier and a fiber length of 40 mm.
And were mixed and a parallel web was created with a parallel card. This was subjected to a high-pressure water stream treatment in the same manner as in Example 1 to entangle the fibers, and then 13 using a hot-air penetrating dryer.
The fiber was heated at 5 ° C. to thermally bond the points where the fibers contact each other.

Comparative Example 2 30% by weight of fiber A and 70% by weight of rayon having a fineness of 1.5 denier and a fiber length of 40 mm.
And were mixed and a parallel web was created with a parallel card. This web was heated at 140 ° C using a hot air penetration dryer.
Was heat-treated to heat-bond the points where the fibers contact each other.

Table 1 shows the evaluation of the physical properties and the feel of the nonwoven fabrics of Examples 1 to 4 and Comparative Examples 1 and 2.

[0032]

[Table 1]

The physical properties of the non-woven fabric were measured by the following methods.

[Thickness, Specific Volume] The thickness of the nonwoven fabric is 3 g /
It was measured with a load of cm ² applied. The specific volume was calculated from the basis weight and the thickness.

[Strength, Elongation] According to JIS L 1096, a 5 × 15 cm sample was stretched at 30 cm / min, and the load value and elongation rate at cutting were taken as the strength and the elongation, respectively.

[Evaluation of Tactile Feeling of Nonwoven Fabric] A sensory test was conducted by 10 panelists, and each sample was ranked in order from the one having the best feeling to touch. The results were tabulated and the feel of each sample was evaluated according to the following criteria. The touch feeling when wet was evaluated by allowing the nonwoven fabric to absorb 2.3 times its own weight of water. ⊚: 8 or more people ranked 1st or 2nd. ◯: Five or more are ranked first to third. Δ: 3 or more people ranked 1st to 3rd. X: No 1st to 3rd place was given.

[0037]

Industrial Applicability The nonwoven fabric of the present invention is bulky and has a soft tactile sensation because it contains crimpable synthetic fibers, and the constituent fibers are intimately entangled by the action of a high-pressure water stream, and thus are soft. It also has a lot of elasticity. Further, the strength of the fibers is improved by heat-bonding the fibers to each other, and when a wet tissue or the like is used in a pop-up system, it is possible to sufficiently withstand the force applied during drawing. Therefore, when this is used for a wet tissue, it is possible to provide the user with an excellent usability that cannot be obtained by the conventional one while maintaining the basic performance such as the conventional strength and water absorption. .

[Brief description of drawings]

FIG. 1 is a side view of a crimpable synthetic fiber in which a three-dimensional crimp is developed.

FIG. 2 is a side view of a crimpable synthetic fiber in which a three-dimensional crimp is developed.

FIG. 3 is a side view of a crimpable synthetic fiber in which a three-dimensional crimp is developed.

FIG. 4 is a cross-sectional view of an example of the crimpable synthetic fiber that can be used in the present invention.

FIG. 5 is a cross-sectional view of an example of the crimpable synthetic fiber that can be used in the present invention.

[Explanation of symbols]

 1 Crimpable synthetic fiber

Claims (6)

[Claims] 1. A non-woven fabric comprising 20 to 50% by weight of crimpable synthetic fibers and 80 to 50% by weight of hydrophilic fibers, wherein the crimpable synthetic fibers are three-dimensionally entangled with each other. A bulky nonwoven fabric having water absorbency, which is characterized by having crimps. 2. The heat-adhesive component comprises 20 to 50% by weight of crimpable synthetic fibers occupying at least a part of the fiber surface and 80 to 50% by weight of hydrophilic fibers, and the fibers are entangled. A bulky nonwoven fabric having water absorbability, wherein the nonwoven fabric is heat-bonded at a point where the fibers are in contact with each other, and three-dimensional crimps are developed in the crimpable synthetic fiber. 3. The bulky nonwoven fabric according to claim 1, wherein 14 to 20 three-dimensional crimps are expressed per inch. 4. An eccentric core-sheath type composite fiber, wherein the crimpable synthetic fiber is a composite fiber composed of high-density polyethylene and polyethylene terephthalate, wherein the first component is a sheath component and the second component is a core component. Alternatively, the bulky nonwoven fabric having water absorbability according to claim 1, 2, or 3, which is a composite fiber in which the first component and the second component are bonded side by side. 5. A crimpable synthetic fiber in which three-dimensional crimp is developed is 20 to 50% by weight, and a hydrophilic fiber is 80 to 50% by weight.
A method for producing a bulky non-woven fabric having water absorbency, which comprises subjecting a fiber web containing a and a high pressure water stream to entangle the fibers. 6. A heat-adhesive component occupies at least a part of the fiber surface, and 20 to 50% by weight of crimpable synthetic fibers in which three-dimensional crimps are expressed, and 80 to 50% by weight of hydrophilic fibers.
After the high pressure water flow treatment is applied to the fiber web containing and to entangle the fibers, heat treatment is performed at a temperature higher than the melting point of the heat-adhesive component to thermally bond the fibers to each other at the point of contact with each other. A method for producing a bulky nonwoven fabric having water absorbency, comprising: [0001]