EP2735632A1

EP2735632A1 - Non-woven fabric and method for fabricating the same

Info

Publication number: EP2735632A1
Application number: EP13003474.7A
Authority: EP
Inventors: Jung-Chi Tai; Chien-Chung Su; Ho-Hsi Yang
Original assignee: Kang Na Hsiung Enterprise Co Ltd
Current assignee: Kang Na Hsiung Enterprise Co Ltd
Priority date: 2012-11-21
Filing date: 2013-07-09
Publication date: 2014-05-28
Also published as: CN103835070A; JP2014101615A; US20140141677A1; TW201420054A

Abstract

A non-woven fabric includes a filament fiber web and a composite fiber web that is entangled with the filament fiber web and that includes composite staple fibers and cellulose fibers. The composite staple fibers and the cellulose fibers are fusion-bonded together. A method of fabricating a non-woven fabric includes: (a) air laying and thermally treating composite staple fibers and cellulose fibers so as to form a composite fiber web, the composite staple fibers and the cellulose fibers in the composite fiber web being fusion-bonded together, and (b) disposing the composite fiber web between two filament fiber webs followed by subjecting to water-jet treatment such that the composite fiber web and the filament fiber webs are entangled with each other.

Description

This invention relates to a non-woven fabric, more particularly to a hygroscopic non-woven fabric which is composed of filament fibers, staple fibers and cellulose fibers.
A paper towel is a necessity in daily life, and can be used to wipe and clean a surface of an article.
The paper towel generally can be classified into dry paper towel and wet paper towel, and should exhibit the properties of softness and good tensile strength and absorbency.
A conventional paper towel is made of two fiber webs by a water-jet treatment, in which the fiber webs are made of a plurality of filament fibers by a carding treatment. The filament fibers are chemical fibers and have a length ranging from 10 mm to 76 mm. Since the filament fiber is relatively expensive, cost of manufacturing the paper towel becomes high, which does not meet industry requirements.
Taiwanese patent publication No. 182129 discloses a wet paper towel which includes two wiping layers and an absorbent layer disposed between the wiping layers. The wiping layers and the absorbent layer are entangled using hot rolling treatment. The wiping layers are made of fibers obtained from the kapok tree and having a length ranging from 1.25 mm to 5 mm. The absorbent layer is made by mixing 50wt% rayon and 50wt% polypropylene fibers followed by subjecting to hot wind treatment. The resultant wet paper towel is relatively rigid and is expensive due to high cost of rayon.
Therefore, it is still required in the art to develop a paper towel which is cost effective.
Therefore, a first object of the present invention is to provide a non-woven fabric, which is cost effective and exhibits desirable mechanical properties.
A second object of the present invention is to provide a method of fabricating the non-woven fabric.
According to a first aspect of this invention, there is provided a non-woven fabric which includes a filament fiber web and a composite fiber web. The composite fiber web is entangled with the filament fiber web and includes composite staple fibers and cellulose fibers. The composite staple fibers and the cellulose fibers are fusion-bonded together.
According to a second aspect of this invention, there is provided a method of fabricating a non-woven fabric, which includes:

(a) air laying and thermally treating composite staple fibers and cellulose fibers so as to form a composite fiber web, the composite staple fibers and the cellulose fibers in the composite fiber web being fusion-bonded together; and
(b) disposing the composite fiber web between two filament fiber webs followed by subjecting to water-jet treatment such that the composite fiber web and the filament fiber webs are entangled with each other.

A non-woven fabric according to the present invention includes a filament fiber web that is made from filament fibers, and a composite fiber web that is entangled with the filament fiber web and that includes composite staple fibers and cellulose fibers. The composite staple fibers and the cellulose fibers are fusion-bonded together.
The non-woven fabric has a basis weight ranging from 20 g/m² to 120 g/m² and a thickness ranging from 0.1 mm to 5 mm. The non-woven fabric of the present invention can be applied to manufacture of a paper towel, a facial mask or a panty liner. Each component of the non-woven fabric of the present invention is illustrated as follows.
The filament fiber suitable for the present invention is a natural fiber, a chemical fiber, or the combination thereof. The natural fiber can be a plant fiber, an animal fiber, or the combination thereof. Examples of the plant fiber include, but are not limited to, seed fibers (such as cotton), bast fibers (such as flax or hemp), nervure fibers (such as Manila hemp), or fruit fibers (such as coconuts). Examples of the animal fiber include, but are not limited to, hide fibers and silk fibers.
The chemical fiber suitable for the present invention is a regenerated fiber, a semi-synthetic fiber, a synthetic fiber, or combinations thereof. An example of the regenerated fiber is rayon. The semi-synthetic fiber is, e.g., cellulose acetate fiber. Examples of the synthetic fiber include polyethylene (abbreviated as PE) fiber, polypropylene (abbreviated as PP) fiber, polyethylene terephthalate (abbreviated as PET) fiber, and polyamide fiber. In consideration of cost of the non-woven fabric of the present invention, preferably, the filament fiber is selected from the group consisting of PE fibers, PP fibers, PET fibers, rayon, cotton fibers, and combinations thereof.
Preferably, the filament fiber is present in an amount ranging from 10wt% to 80wt% based on 100wt% of the hygroscopic non-woven fabric. The filament fiber has a linear density ranging from 1 denier to 6 deniers per filament. The filament fibers have lengths ranging from 10 mm to 76 mm.
The composite staple fiber has thermofusible ability, and thus can be fusion-bonded with the adjacent cellulose fibers. Thus, the cellulose fibers would not be lost during a subsequent water-jet treatment, thereby eliminating the inferior absorbency problem of the hygroscopic non-woven fabric and difficulty in wastewater treatment.
The composite staple fiber suitable for the present invention is selected from the group consisting of a polyethylene-polypropylene fiber, a polyethylene-polyethylene terephthalate fiber, a low temperature poly lactic acid-high temperature poly lactic acid fiber, a maleic anhydride modified polyethylene-polypropylene fiber, a maleic anhydride modified polyethylene-polyethylene terephthalate fiber, and combinations thereof. In an example of this invention, the composite staple fiber is the polyethylene-polypropylene fiber.
Preferably, the composite staple fiber is present in an amount ranging from 1wt% to 20wt% based on 100wt% of the non-woven fabric. The composite staple fiber has a linear density ranging from 1 denier to 6 deniers per filament. The composite staple fibers have lengths ranging from 1 mm to 10 mm.
In this embodiment, the cellulose fiber is a natural cellulose fiber, and is present in an amount ranging from 5wt% to 60wt% based on 100wt% of the non-woven fabric. The cellulose fiber has a linear density ranging from 0.1 denier to 10 deniers per filament. Preferably, the cellulose fiber has a length ranging from 1 mm to 5 mm.
The cellulose fiber can be obtained from pulp, e.g., wood pulp.
A method of fabricating the non-woven fabric of this invention includes the following steps:

The air-laying treatment in step (a) is conducted using air as a carrier for the fibers. The composite staple fibers and the cellulose fibers are dispersed evenly in the gas (e.g., air) by air flowing, and are adsorbed onto a screen mesh, so as to form the composite fiber web. The air-laying treatment can be conducted using a traditional air-laying machine. The airflow volume used in the air-laying treatment ranges from 100 CMM to 1000 CMM.
The thermal treatment is conducted to fusion-bond the composite staple fibers and the cellulose fibers together. The thermal treatment can be conducted using traditional heating equipment. The heat treatment is conducted at a temperature ranging from 50°C to 180°C. The composite fiber web has a basis weight ranging from 5 g/m² to 100 g/m² and a thickness ranging from 0.1 mm to 10 mm.
Each of the filament fiber webs used in step (b) is formed by carding the filament fibers.
The carding treatment can be conducted using traditional carding equipment. The filament fiber web has a basis weight ranging from 5 g/m² to 100 g/m² and a thickness ranging from 0.1 mm to 10 mm.
The water-jet treatment is conducted using a high pressure waterjet to render the fusion-bonded fibers in the composite fiber web to be entangled with the filament fibers in the filament fiber webs. The water-jet treatment can be conducted using traditional water-jet equipment.
The following examples are provided to illustrate the preferred embodiments of the invention, and should not be construed as limiting the scope of the invention.

Example 1:

10wt% polyethylene-polypropylene staple fibers (the average length was 6 mm) and 50wt% pulp were mixed to form a composite fiber mixture, followed by air-laying treatment (the airflow volume was 130 CMM) and thermal treatment at a temperature of 135°C, thereby obtaining a composite fiber web.
20wt% solid core polyethylene terephthalate filament fibers and shape 4T polyethylene terephthalate filament fibers (the average length thereof was 38 mm) were subj ected to carding treatment so as to obtain filament fiber webs.
The composite fiber web was disposed between the two filament fiber webs followed by subjecting to water-jet treatment under 50 bar of waterjet pressure so as to obtain a non-woven fabric.

Examples 2 to 6 and Comparative Example:

Examples 2 to 6 and Comparative Example were conducted in a manner similar to that of Example 1 except for the material and amount of the filament fiber, the composite staple fiber, and/or the cellulose fiber. The material and the amount of each of the fiber components are listed in Table 1.

1. Basis weight (g/m²) :

The basis weight was measured by ASTM D3776-85 under the following conditions: the temperature of 23±0.5°C, the relative humidity of 65±2% and the normal atmospheric pressure. The results are shown in Table 1.

2. Tensile strength (Kgf/25 mm):

The non-woven fabrics of Examples 1 to 6 and Comparative Example were cut into samples having 150 mm length and 25.4 mm width, and the tensile strength thereof was measured by ASTM D-1117. The results are shown in Table 1.

3. Elongation rate (%):

The non-woven fabrics of Examples 1 to 6 and Comparative Example were cut into samples having 150 mm length and 25.4 mm width and the elongation rate thereof was measured by ASTM D-1117. The results are shown in Table 1.

4. Water content (%):

Each of the non-woven fabrics of Examples 1 to 6 and Comparative Example was weighed to obtain a weight of W1, and was dried for 2 hours at the temperature of 105±2 °C in a hot-air circulation oven. Each of the dried non-woven fabrics was then cooled for 20 minutes to 30 minutes in a desiccator, and was weighed to obtain a weight of W2. The water content was calculated using the following formula: $Water content (%) = [(W 1 - W 2) / W 1] \times 100 %$

5. Absorbency (%):

According to ISO 9073.6:2000, seven bags made of non-woven fabric and each having a size specification of 26cmx30cmx20cm were weighed respectively to obtain a weight of W1, and an open end of each of the bags was sealed, followed by soaking into pure water for 5 minutes. Each of the bags was then placed onto a wire netting (10 meshes) to drip for 1 minute, followed by weighing to obtain a weight of W2.
Each of the non-woven fabrics of Examples 1 to 6 and Comparative Example was weighed to obtain a weight of (W3) and was placed into a respective one of the bags, followed by sealing the open ends of the bags, and soaking into pure water for 5 minutes. Each of the bags with the fabric was then placed onto the wire netting (10 meshes) to drip for 1 minute, followed by weighing to obtain a weight of W4. The absorbency is calculated based on the following formula: $Absorbency (%) = \{[W 4 - W 3 - W 2 / W 3]\} \times 100 %$

6. Softness (cm):

The non-woven fabrics of Examples 1 to 6 and Comparative Example were cut into samples with the length of 250 mm and the width of 25 mm, and were placed under the conditions of the temperature of 23°C and the relative humidity of 50% for 24 hours, followed by subjecting to softness test according to ISO 9073-7:1995 and ASTM D-1117.
The softness test was conducted based on the following procedure using a flexural rigidity tester which included a horizontal platform and an inclined surface that was inclined at 45° relative to the horizontal platform.

Each of the aforesaid samples was placed onto a horizontal platform of the flexural rigidity tester and moved gradually on the horizontal platform toward the inclined surface of the flexural rigidity tester until a leading edge of the sample dropped and touched the inclined surface. The length (mm) of the sample from the leading edge to a junction of the horizontal platform and the inclined surface was measured. The above steps were repeated six times and an average (C) of the length was computed. In addition, this whole procedure was performed once with either side of each of the samples facing upward and with either of the lengthwise and widthwise edges leading the way. The average length (mm) used to stand for softness was shown in Table 1.

Table 1

		Examples						Comp. Exp.
		1	2	3	4	5	6
Filament Fiber (wt%)	rayon	--	10	--	--	--	--	40
	PET	20	30	50	55	40	45	60
	Shape 4T PET	20	--	--	--	--	--	--
Staple Fiber (wt%)	PE/PP	10	10	10	5	10	5	--
Cellulose Fiber (wt%)	Pulp	50	50	40	40	50	50	--
Basis Weight (g/m²)		45.08	48.4	54.3	51.2	55.5	46.4	49.9
Thickness (mm)		0.52	0.53	0.63	0.52	0.53	0.56	0.58
Tensile Strength in Longitudinal Direction (Kgf/25mm)		1.55	1.40	3.57	3.47	2.49	2.57	5.10
Elongation Rate in Longitudinal Direction (%)		51	49	63.6	60.8	58.6	54.9	44
Tensile Strength in Lateral Direction (Kgf/25mm)		0.27	0.26	0.74	0.85	0.37	0.62	1.48
Elongation Rate in Lateral Direction (%)		178.9	139.6	188.1	186.9	181.5	169.5	141
Water Content (%)		5.89	5.81	3.19	3.14	4.64	4.15	4.13
Softness (mm)		55.5	57.4	57.4	63.4	61.8	55.6	45.0
Absorbency (%)		1038	1032	1051	1064	1041	1103	996

As shown in Table 1, the non-woven fabric of the present invention that uses composite staple fibers and cellulose fiber to replace some of the filament fibers has superior elongation rate and absorbency as compared to the non-woven fabric of the comparative example. Other properties, e.g., tensile strength, water content, and softness also meet industrial requirements.
To sum up, the non-woven fabric of the present invention that uses composite staple fibers and cellulose fibers has reduced cost and superior elongation rate and improved absorbency. Furthermore, the air-laying treatment, thermal treatment, carding treatment and water-jet treatment can be combined in a production line to efficiently fabricate the non-woven fabric of the present invention.

Claims

A non-woven fabric characterized by:
a filament fiber web; and

a composite fiber web that is entangled with the filament fiber web and that includes composite staple fibers and cellulose fibers, said composite staple fibers and said cellulose fibers being fusion-bonded together.
The non-woven fabric of claim 1, characterized in that said filament fiber web includes filament fibers selected from the group consisting of polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, rayon, cotton fibers and combinations thereof.
The non-woven fabric of claim 2, characterized in that said filament fibers have lengths ranging from 10 mm to 76 mm.
The non-woven fabric as claimed in any one of Claims 2 and 3, characterized in that said filament fibers are present in an amount ranging from 10 wt% to 80 wt% based on the total weight of said non-woven fabric.
The non-woven fabric as claimed in any one of Claims 1 to 4, characterized in that said composite staple fibers are selected from the group consisting of polyethylene-polypropylene fibers, polyethylene-polyethylene terephthalate fibers, low temperature poly lactic acid-high temperature poly lactic acid fibers, maleic anhydride modified polyethylene-polypropylene fibers, maleic anhydride modified polyethylene-polyethylene terephthalate fibers, and combinations thereof.
The non-woven fabric as claimed in any one of Claims 1 to 5, characterized in that said composite staple fibers have lengths ranging from 1 mm to 10 mm.
The non-woven fabric as claimed in any one of Claims 1 to 6, characterized in that said composite staple fibers are present in an amount ranging from 1 wt% to 20 wt% based on the total weight of said non-woven fabric.
The non-woven fabric as claimed in any one of Claims 1 to 7, characterized in that said cellulose fibers are present in an amount ranging from 5 wt% to 60 wt% based on the total weight of said non-woven fabric.
The non-woven fabric as claimed in any one of Claims 1 to 8, characterized in that said cellulose fibers have lengths ranging from 1 mm to 5 mm.
A method of fabricating a non-woven fabric, characterized by:
(a) air laying and thermally treating composite staple fibers and cellulose fibers so as to form a composite fiber web, the composite staple fibers and the cellulose fibers in the composite fiber web being fusion-bonded together; and

(b) disposing the composite fiber web between two filament fiber webs followed by subjecting to water-jet treatment such that the composite fiber web and the filament fiber webs are entangled with each other.
The method of claim 10, characterized in that the filament fiber web includes filament fibers as defined in any of claims 2-4.
The method of claim as claimed in any one of Claims 10 or 11, characterized in that the composite staple fibers are defined as in any of claims 5-7.
The method as claimed in any one of Claims 10 to 12, characterized in that the cellulose fibers are present in an amount ranging from 5 wt% to 60 wt% based on the total weight of said non-woven fabric.
The method as claimed in any one of Claims 10 to 13, characterized in that the cellulose fibers have lengths ranging from 1 mm to 5 mm.