JP2016108694A - Method for producing excellently water-absorptive nonwoven fabric with uneven pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for obtaining a nonwoven fabric, in which uneven patterns can be hardly erased and the nonwoven fabric has an improved water-absorptivity.SOLUTION: There is provided a polyester nonwoven fabric composed of polyester filaments. The polyester filament has an approximately Y4-shaped cross section. On the other hand, a cotton web consisting mainly of cotton fibers is provided. The cotton webs are laminated on front and back surfaces of the polyester nonwoven fabric to obtain a triple-layer structure web. The triple-layer structure web is subjected to a high-pressure water stream to integrate the triple-layer structure web. The integrated triple-layer structure web is passed through a pair of rolls with a polka-dot pattern. The roll with a polka-dot pattern has hemispheric protrusion parts 12 and hemispheric recess parts 11 arranged alternately on a peripheral surface thereof, and each protrusion part 12 and each recess part 11 of the roll with a polka-dot pattern rotate by engaging with each other.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for producing a nonwoven fabric having a clear concavo-convex pattern and excellent water absorption.

  Conventionally, nonwoven fabrics made of hydrophilic fibers such as cotton fibers and rayon fibers are known as nonwoven fabrics excellent in water absorption used for wipes and the like. Moreover, the uneven | corrugated pattern pattern is also given by embossing to this nonwoven fabric. However, even if a concave / convex pattern is provided, the concave / convex pattern tends to disappear by compressing in the thickness direction. In order to make the uneven pattern difficult to disappear, the nonwoven fabric itself may be made rigid. However, when the nonwoven fabric itself is made rigid, the water absorption is sometimes lowered.

形状（以下、「略Ｙ４形状」という。）であることを特徴とするポリエステル不織布というものである。かかるポリエステル不織布は、高剛性であるという特性を持っている。 By the way, this inventor developed the polyester nonwoven fabric with a special cross-sectional shape (patent document 1). This is a non-woven fabric comprising polyester long fibers as a constituent fiber, and the cross-sectional shape of the polyester long fibers is connected to the top, bottom, left and right at the lower end of a substantially Y-shape.

It is a polyester nonwoven fabric characterized by having a shape (hereinafter referred to as “substantially Y4 shape”). Such a polyester nonwoven fabric has a characteristic of high rigidity.

JP2013-76182A

  The present inventor has conducted various studies using the polyester nonwoven fabric, and when laminating a cotton fiber layer on the front and back surfaces of the polyester nonwoven fabric and applying a specific embossing to give a concavo-convex pattern, the thickness direction The present inventors have found that a nonwoven fabric with improved water absorption can be obtained while the pattern pattern is not easily lost even when compressed to. The present invention is based on such knowledge. Accordingly, an object of the present invention is to obtain a non-woven fabric having an uneven pattern which is hardly lost and which has improved water absorption.

形状（以下、「略Ｙ４形状」という。）であり、前記水玉ロールは、その周面に半球状の凸部と凹部が交互に並んでいて、かつ、各水玉ロールの凸部と凹部は噛合して回転していることを特徴とする凹凸柄模様を持つ吸水性に優れた不織布の製造方法に関するものである。 This invention solves the said subject by combining the long fiber nonwoven fabric and cotton fiber layer of patent document 1, and giving a specific embossing. That is, in the present invention, after forming a three-layer structure web by laminating a cotton web mainly composed of cotton fibers on the front and back surfaces of a polyester nonwoven fabric composed of polyester long fibers, The cotton web side is subjected to high pressure water flow, the cotton fibers and the polyester long fiber nonwoven fabric are entangled, and then embossed through a pair of polka dot rolls, the cross section of the polyester long fibers The shape is connected to the top, bottom, left and right at the lower end of the approximate Y-shape.

The polka dot roll has a shape (hereinafter referred to as “substantially Y4 shape”), hemispherical convex portions and concave portions are alternately arranged on the peripheral surface, and the convex portions and the concave portions of each polka dot roll mesh with each other. It is related with the manufacturing method of the nonwoven fabric excellent in the water absorption which has the uneven | corrugated pattern pattern characterized by rotating.

  First, the polyester continuous fiber used by this invention is demonstrated. This polyester continuous fiber is characterized by its cross-sectional shape. This cross-sectional shape has four substantially Y-characters as shown in FIG. And it is connected to the upper and lower sides and the right and left at the lower end 1 of a substantially Y shape, and has a substantially Y4 shape as shown in FIG. The substantially Y4 shape has four concave portions 2, eight convex portions 3, and four small concave portions 4. In this way, it has a large number of concave portions 2, a large number of small concave portions 4, and a large number of convex portions 3, and is excellent in bulkiness. Therefore, even if the polyester long fibers are accumulated and the long fibers are bonded to each other. The passage of high-pressure water flow is good. In addition, dust is easily captured at the four recesses 2 and is excellent in dust removal. Further, high rigidity is achieved by the substantially + -shaped part 5 at the center and the four approximately V-shaped parts 6 connected to the respective tips of the approximately + -shaped part 5. In other words, it is not a simple shape such as a hexagon or a Y-shape, but a higher rigidity is achieved by a combination of the substantially + -shaped portion 5 and the substantially V-shaped portion 6 having high rigidity. Such polyester long fibers are accumulated to prepare a highly rigid polyester nonwoven fabric. In particular, it is possible to prepare a bulky and high-rigidity polyester nonwoven fabric by bonding the long polyester fibers by heat fusion.

The polyester continuous fiber may be composed of one kind of polyester, but it is preferable to combine a low-melting polyester and a high-melting polyester. That is, it is preferable to use a composite type in which the substantially V-shaped portion 6 of the cross-sectional shape of the polyester long fiber is formed of low-melting polyester and the substantially + -shaped portion 5 is formed of high-melting polyester. This is because the polyester nonwoven fabric in which the polyester long fibers are heat-fused with the low melting point polyester is obtained by softening or melting the low melting point polyester after the composite type polyester long fibers are accumulated and then solidifying. Moreover, it is preferable that the fineness of the polyester long fiber which comprises a polyester nonwoven fabric is 10 decitex or more. When the fineness is less than 10 dtex, the rigidity of the long fibers tends to decrease, and as a result, the rigidity of the polyester nonwoven fabric tends to decrease. Moreover, it is preferable that the fabric weight of a polyester nonwoven fabric is 15-70 g / m < ² >. When the basis weight is less than 15 g / m ² , the polyester nonwoven fabric tends to have low rigidity. If the basis weight exceeds 70 g / m ² , the high-pressure water flow tends to deteriorate. The details of the polyester nonwoven fabric used in the present invention are described in detail in Patent Document 1 described above.

  A cotton web mainly composed of cotton fibers is laminated on the front and back surfaces of the prepared polyester nonwoven fabric to form a three-layer structure web. The cotton web is mainly composed of cotton fibers, but may contain other rayon short fibers, polyester short fibers, polyamide short fibers, and the like.

  The three-layer web is subjected to a high-pressure water flow from the front surface and / or the back surface side. The high-pressure water stream is for entanglement of cotton fibers and polyester long fibers, and is generally obtained by spraying water at a pressure of 5 to 14 MPa from a spray hole having a hole diameter of 0.05 to 2.0 mm. It is. The high-pressure water stream is preferably applied to both the front surface and the back surface side, so that the cotton fibers constituting the cotton web are entangled with the polyester long fibers in the polyester nonwoven fabric and the three-layer structure web is integrated.

  The integrated three-layer web contains moisture from the high-pressure water stream and is dried to remove the moisture. Thereafter, it is embossed by passing between a pair of polka dot rolls. Here, the polka dot roll is a roll in which hemispherical convex portions and concave portions are alternately arranged on the peripheral surface. Specifically, it has the peripheral surface shown in FIGS. FIG. 3 is a plan view showing a part of the peripheral surface of the polka dot roll. 11 is a concave portion, 12 is a convex portion, and 13 is a flat portion. FIG. 4 is a vertical cross-sectional view taken along the line AA of the polka dot roll shown in FIG. 3 (a cross-sectional view taken along the axial direction of the polka dot roll from the line AA). The pitch between the concave portions and the convex portions may be arbitrary, but is generally about 5 to 10 mm. Moreover, although the depth of a recessed part and the height of a convex part may be arbitrary, generally it is about 0.5-1.5 mm. In this pair of polka dot rolls, one convex portion 12 meshes with the other concave portion 11, and one concave portion 11 meshes with the other convex portion 12 and rotates. When an integrated three-layer structure web is passed between the pair of rotating polka dot rolls, a nonwoven fabric having a concavo-convex pattern conforming to the peripheral shape of the polka dot roll is obtained. The linear pressure applied to the three-layer structure web in which the pair of polka dot rolls are integrated is also arbitrary, but is preferably about 50 to 100 kgf / cm. The pair of polka dot rolls is preferably heated, and the heating temperature is lower than the melting point of the polyester long fiber, and preferably about 100 to 170 ° C.

  The nonwoven fabric obtained as described above has a shape that matches the shape of the peripheral surface of the polka dot roll, and has a clear concavo-convex pattern. Such a nonwoven fabric is used for conventionally known applications, and can be suitably used for, for example, a wipe, a water absorbent sheet such as a tray mat or a drip sheet, an air filter material, or a packaging material.

  The nonwoven fabric obtained by the method according to the present invention is one in which cotton fibers having water absorbency are unevenly distributed on the front and back surfaces of a highly rigid polyester nonwoven fabric, and has a concavo-convex pattern as a whole. In such a nonwoven fabric, since a high-rigidity polyester nonwoven fabric is disposed in the intermediate layer, even if a load is applied in the thickness direction of the nonwoven fabric, the uneven pattern pattern is hardly lost. In addition, the bulky polyester nonwoven fabric is arranged in the intermediate layer, and the front and back surfaces are provided with an uneven pattern, so that the moisture absorbed by the cotton fibers present on the front and back surfaces is quickly diffused. Play.

Example 1
[Preparation of polyester nonwoven fabric]
Copolymerization was carried out using terephthalic acid (TPA) 92 mol% and isophthalic acid (IPA) 8 mol% as the dicarboxylic acid component, and ethylene glycol (EG) 100 mol% as the diol component, and a low-melting polyester (relative viscosity [ηrel] 1. 44, melting point 230 ° C.). To this low melting point polyester, 4.0% by mass of titanium oxide was added as a crystal nucleating agent to prepare a low melting point polyester resin. On the other hand, 100 mol% of terephthalic acid (TPA) as a dicarboxylic acid component and 100 mol% of ethylene glycol (EG) as a diol component were copolymerized to obtain a high melting point polyester resin (polyethylene terephthalate, relative viscosity [ηrel] 1.38, melting point 260). ℃) was prepared. Then, using the nozzle hole shown in FIG. 5, a low melting point polyester resin is supplied to the V-shaped part, and a high melting point polyester resin is supplied to the + -shaped part, and the spinning temperature is 285 ° C., the single-hole discharge rate is 8.33 g / Melt spun in minutes. In addition, the weight ratio of the supply amount of the low melting point polyester resin and the supply amount of the high melting point polyester resin was 1: 2.

The filament group discharged from the nozzle hole was introduced into the air soccer entrance 2 m below and pulled so that the fineness of the composite polyester long fiber was 17 dtex. The composite polyester long fiber group discharged from the air soccer exit was opened with a fiber opening device and then collected on a moving net conveyor to obtain a fiber web. This fiber web is heat-fused with a flat roll and an embossing roll having a surface temperature of 213 ° C. (the area at the tip of each embossing protrusion is 0.7 mm ² and the area ratio of the embossing protrusion relative to the total area of the roll is 15%). The polyester non-woven fabric having a basis weight of 40 g / m ² was obtained by heat-sealing the composite polyester long fibers with a low melting point component under the condition of a linear pressure of 30 kgf / cm between both rolls.

[Preparation of cotton web]
On the other hand, using a scoured and bleached cotton fiber (fiber length of about 25 to 35 mm), a cotton web having a basis weight of 30 g / m ² was prepared using a sample roller card machine manufactured by Yamato Kiko Co., Ltd.

[Manufacture of nonwoven fabric with uneven pattern]
The above-described cotton web was laminated on the front and back surfaces of the above-described polyester nonwoven fabric to prepare a three-layer structure web. Then, this three-layer structure web was placed on a 100-mesh stainless steel net, and a high-pressure water flow was applied from the cotton web layer laminated on the surface of the polyester nonwoven fabric under the conditions of a nozzle diameter of 0.13 mm and a water pressure of 8.33 MPa. Next, the three-layer structure web was inverted, and a high-pressure water stream was applied under the same conditions from the cotton web side laminated on the back surface of the polyester nonwoven fabric to obtain an integrated three-layer structure web.

After the moisture was removed from the integrated three-layer structure web by drying, it was passed through a pair of polka dot rolls to obtain a nonwoven fabric having an uneven pattern. The basis weight of this nonwoven fabric was 100 g / m ² . Here, the polka dot roll has the concave portions and the convex portions shown in FIGS. 3 and 4, the pitch between the concave portions and the convex portions is 6.92 mm, the depth of the concave portions and the height of the convex portions. Is 0.9 mm. In addition, while the pair of polka dot rolls is heated to 140 ° C., one concave portion is engaged with the other convex portion and one convex portion is engaged with the other concave portion and rotated to pass the integrated three-layer structure web. did. The linear pressure of the pair of polka dot rolls was 66.7 kgf / cm.

Comparative Example 1
A polyester nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the polyester nonwoven fabric was changed to 100 g / m ² . This polyester nonwoven fabric was passed between a pair of polka dot rolls used in Example 1 without laminating a cotton web to obtain a polyester nonwoven fabric having an uneven pattern.

Comparative Example 2
A cotton web was obtained in the same manner as in Example 1 except that the polyester nonwoven fabric was not used and the basis weight of the cotton web was changed to 100 g / m ² . This cotton web was placed on a 100-mesh stainless steel net and subjected to a high-pressure water flow under the conditions of a nozzle diameter of 0.13 mm and a water pressure of 8.33 MPa to obtain a cotton nonwoven fabric. This cotton nonwoven fabric was passed between the pair of polka dot rolls used in Example 1 to obtain a cotton nonwoven fabric having an uneven pattern.

For the nonwoven fabric having the concavo-convex pattern obtained in Example 1, the polyester nonwoven fabric having the concavo-convex pattern obtained in Comparative Example 1, and the cotton nonwoven fabric having the concavo-convex pattern obtained in Comparative Example 2, the compression strain and water absorption tests were performed. went. The compression strain test was performed by the following method. Each sample nonwoven fabric is sandwiched between flat plates and an initial load of 20 gf / cm ² is applied to measure the thickness of the sample. Thereafter, the load was increased to 10 to 137 gf / cm ² and increased, and the reduction rate of thickness was calculated. The thickness reduction rate is calculated by the formula [(t0−t1) / t0] × 100 (%). Here, t0 is the thickness of the sample when an initial load of 20 gf / cm ² is applied, and t1 is the thickness of the sample when the load is increased. Further, the water absorption test was performed by the birec method described in JIS L 1907. Table 1 shows the results of the compression strain test, and Table 2 shows the results of the water absorption test.

[Table 1]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Reduction rate of thickness (%)
Additional load (gf / cm ² ) ━━━━━━━━━━━━━━━━━━━━━
Example 1 Comparative Example 1 Comparative Example 2
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
10 1.5 1.1 1.8
20 3.2 2.3 3.6
50 8.1 5.2 8.8
83 13.1 7.9 14.3
93 14.5 8.7 16.0
103 16.0 9.4 17.8
133 20.7 11.2 23.9
137 22.2 11.7 25.6
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[Table 2]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Water absorption (cm) Example 1 Comparative example 1 Comparative example 2
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MD 14.6 3.0 12.9
CD 13.6 2.5 13.2
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Note) MD is the vertical direction (machine direction) of the sample, and CD is the horizontal direction (direction orthogonal to the machine direction) of the sample, and indicates water absorption (cm) in each direction.

  As can be seen from the results of Example 1 and Comparative Examples 1 and 2, when the nonwoven fabric was compressed in the thickness direction, the nonwoven fabric obtained by the method according to Example 1 was compared with the nonwoven fabric obtained by the method according to Comparative Example 2. Thus, it is difficult to compress, and it is understood that the attached uneven pattern pattern is difficult to disappear. Moreover, when the nonwoven fabric is made to absorb water, it can be seen that the nonwoven fabric obtained by the method according to Example 1 is more likely to diffuse the absorbed water than the nonwoven fabric obtained by the methods according to Comparative Examples 1 and 2.

It is the figure which showed one substantially Y character of the substantially Y4 shape which is the cross-sectional shape of the polyester long fiber used by this invention. It is the figure which showed the substantially Y4 shape which is the cross-sectional shape of the polyester continuous fiber used by this invention. It is the top view which showed a part of peripheral surface of the polka dot roll used by this invention. It is the AA longitudinal cross-sectional view of the polka dot roll shown in FIG. It is the figure which showed the shape of the spinning hole used when manufacturing the polyester nonwoven fabric used in Example 1. FIG.

DESCRIPTION OF SYMBOLS 1 Lower end of one substantially Y shape of the substantially Y4 shape which is the cross-sectional shape of a polyester continuous fiber 2 The recessed part formed in the substantially Y4 shape 3 The convex part formed in the substantially Y4 shape 4 The small recessed part formed in the substantially Y4 shape 5 About + character part in about Y4 shape 6 About V character part in about Y4 shape 11 Concave part of polka dot roll 12 Convex part of polka dot roll 13 Flat part of polka dot roll

Claims (3)

After forming a three-layer structure web by laminating a cotton web mainly composed of cotton fibers on the front and back surfaces of a polyester nonwoven fabric composed of polyester long fibers, a high pressure is applied from the cotton web side of the three-layer structure web. A method of applying water flow to entangle the cotton fibers and the polyester non-woven fabric, and then embossing them through a pair of polka dots rolls,
The cross-sectional shape of the polyester continuous fiber is connected to the top, bottom, left and right at the lower end of a substantially Y shape.

Shape (hereinafter referred to as “substantially Y4 shape”),
The polka dot roll has an uneven pattern characterized in that hemispherical convex portions and concave portions are alternately arranged on the peripheral surface, and the convex portions and concave portions of each polka dot roll are meshed and rotated. A method for producing a nonwoven fabric having excellent water absorption.   The polyester long fiber is a composite type polyester long fiber in which each substantially V-shaped portion of a substantially Y4 shape is made of a low-melting polyester, and the other substantially + -shaped portion is made of a high-melting polyester, The method for producing a nonwoven fabric excellent in water absorption having a concavo-convex pattern according to claim 1, wherein a polyester nonwoven fabric in which the composite polyester long fibers are engaged with each other by wearing is used.   The manufacturing method of the nonwoven fabric excellent in the water absorption which has a concavo-convex pattern pattern of Claim 1 using a pair of heated polka dot roll.

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