JPH05177696A - Flexible perforated plastic sheet and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a flexible and perforated plastic sheet being suitable for a liq.-permeable surface sheet for a humor treating product having little sticky touch to the skin and surface luster. CONSTITUTION:A flexible and perforated plastic sheet 1 has ribs 2 and 3 in the first and second directions crossing each other and adjoining two lines of the ribs 2 in the first direction and adjoining two lines of the ribs 3 in the second direction cross each other to form a liq.-permeable opening 4. In these crossings, at the first crossing part 5, the ribs 2 in the first direction rise and at the second crossing part 6, the ribs 3 in the second direction rise. The first crossing parts 5 are placed along each of the ribs 2 and 3 in the first and second directions and periodically placed so as to be continued two or more. A plastic sheet 1 with a complicated unevenness on the surface and little sticky touch to the skin and surface luster can be obtd. by these ribs 2 and 3. This plastic sheet 1 can be obtd. by thermoforming 1 a flexible thermoplastic plastic sheet on a twill-woven net.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-permeable flexible open-hole plastic sheet suitable for use in body fluid treatment products such as disposable diapers and sanitary napkins.

[0002]

2. Description of the Related Art Conventionally, an open-pore plastic sheet obtained by thermoforming a flexible thermoplastic sheet such as polyethylene on a liquid-permeable surface sheet of a body fluid treatment article is sometimes used. However, since the surface sheet is used in close contact with the skin, the sticky texture and the glossy appearance peculiar to the plastic sheet are not generally preferred, and therefore the sheet surface is provided with undulations and fine irregularities. In some cases, the contact area when touching the skin is reduced and light is diffusely reflected on the sheet surface to improve the touch and appearance. For example, U.S. Pat. No. 4,342,314 relating to this type of modification technique.
The No. is a thermoplastic sheet that is thermoformed on a screen with a rib structure in which a plurality of metal plates having a predetermined opening pattern are laminated. It is revealed that a plastic sheet having a flexible capillary is obtained.
Further, Japanese Patent Application Laid-Open No. 58-1517 relates to a non-opened plastic sheet.
The wire diameter is 0.025-0.05mm
By thermoforming on a 400 mesh / 25.4 mm fine mesh screen, it was clarified that a plastic sheet having fine irregularities on the sheet surface and having a non-glossy, cloth-like feel was obtained. There is.

[0003]

The various techniques for modifying the feel and appearance of the plastic sheet of the body fluid treatment product targeted by the present invention have advantages and disadvantages. For example, in the technique of U.S. Pat. No. 4,342,314, the skin-contacting surface of the plastic sheet formed by the screen having a smooth surface is substantially smooth like a thin metal plate, It may give a sticky feel when it comes into close contact with the skin. In the above-mentioned JP-A-58-15178,
Even if the feel and appearance of the plastic sheet are modified,
A liquid permeable sheet cannot be obtained without further provision of suitable opening means.

Therefore, according to the present invention, by thermoforming a plastic sheet on a twill weave wire mesh having a relatively coarse mesh,
A flexible open-ended plastic suitable for liquid-permeable surface sheets of body fluid treatment products, which has liquid-permeable holes, has a highly undulating surface, has a less sticky feel, is soft to the touch, and has a low surface gloss. The challenge is to get a seat.

[0005]

The gist of the present invention to solve the above problems is as follows.

A flexible hole plastic sheet according to the present invention
In the case of g., The woven appearance is obtained by intersecting a plurality of first-direction ribs whose both sides bend downward along the first direction and a plurality of second-direction ribs whose both sides bend downward along the second direction. Is present.

Further, two adjacent ribs in the first direction and two adjacent ribs in the second direction intersecting the two ribs in the first direction define a liquid-permeable opening. ing.

The first direction rib and the second direction rib intersecting each other.
The first direction ribs bulge at the first intersection formed by the directional ribs to form ridges extending along the first direction, and lower edges on both sides of the ridge and the tops of the second direction ribs extending along the second direction. And are connected. On the other hand, at the second intersecting portion, the second-direction rib is raised to form a raised portion extending in the second direction, and lower edges on both sides of the raised portion are connected to the top portions of the first-direction ribs extending in the first direction. There is.

Further, in each of the first-direction ribs and the second-direction ribs, a predetermined number of first intersecting portions that are continuous by two or more are periodically arranged via a predetermined number of second intersecting portions that is one or more.

Further, according to the present invention, the flexible thermoplastic sheet is molded by following the twill weave wire mesh, and the flexible open hole plastic sheet is formed by the thermoforming step of bulging and bursting between the wire rods of the wire mesh. To get

In a preferred embodiment of the present invention, a step of widening the plastic sheet is provided after the thermoforming step.

[0012]

In the flexible perforated plastic sheet according to the present invention, the first direction rib and the second direction rib whose both tops are bent downward intersect each other, and the ribs intersecting each other define the aperture.
Moreover, the liquid permeability and the woven appearance can be obtained by repeating the undulation of each rib. Such ribs form many complicated undulations and ridges on the surface of the plastic sheet, so that the gloss of the sheet surface becomes poor. In addition, due to these undulations and ridges, this sheet has a small contact area with the skin, and the sticky feeling peculiar to the plastic sheet is poor, and the feel is good.

When a predetermined number of two or more first intersecting portions are continuously arranged in each of the first-direction ribs and the second-direction ribs, the lower edges of the first-direction ribs and the tops of the second-direction ribs are arranged. It is possible to continuously arrange the intersecting portions in the form of connecting with each other along the second direction ribs.

The flexible perforated plastic sheet having a woven appearance can be obtained by thermoforming a flexible thermoplastic sheet in the form of a twill weave mesh.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic plan view of a flexible apertured plastic sheet 1 according to the present invention when the rib tops are viewed upward. The seat 1 includes a first direction rib 2 extending in the longitudinal direction (individual ribs are referred to as 2A, 2B, 2C ...), and a second direction rib 3 extending in the lateral direction (individual ribs are 3).
A), 3B, 3C ...), and two adjacent first direction ribs 2 and two second direction ribs 3 intersecting the first direction ribs 2 and adjacent to each other. And a liquid-permeable opening 4.

In FIG. 1, the first and the second intersect with each other.
The direction ribs 2 and 3 are such that the first direction rib 2 is located above the second direction rib 3 at the first intersection portion 5, and the second direction rib 3 is located above the first direction rib 2 at the second intersection portion 6. positioned. In each of the first direction rib 2 and the second direction rib 3, two continuous first intersecting portions 5 are repeatedly arranged via one second intersecting portion 6.

2 and 3 show II-I in FIG.
It is an I and III-III line arrow line view. Both ends of each rib extending in the left-right direction in the drawing are cut obliquely and are used as a reference for understanding the three-dimensional shape of the rib.

In FIG. 2, the first direction rib 2 is raised at the first intersecting portion 5 to form a raised portion 7 extending in the vertical direction of FIG.
The lower edges 11 on both sides of the raised portion 7 are connected to the top portions 12 of the second direction ribs 3 along the lateral direction in FIG. Second intersection 6
Then, the second direction rib 3 is raised to form a raised portion 8 extending in the lateral direction of FIG. All second direction ribs (3A, 3
B, 3C, ...) have the intersections 5 and 6 arranged along the longitudinal direction thereof as shown in FIG.
It has been undulated between.

FIG. 3 shows the undulating state of the first direction ribs 2. In the first direction ribs 2, the first intersecting portions 5 are adjacent to each other, and the ridge portions 7 of one first intersecting portion 5 are connected to the ridge portions 7 of the adjacent first intersecting portions 5 and extend along the longitudinal direction of the rib. An integral raised portion 14 is formed. At the second intersecting portion 6, both lower edges 13 of the second direction rib 3 and the top portion 10 of the first direction rib 2 are connected. All first direction ribs (2
A, 2B, 2C ...) are arranged with their crossing portions 5 and 6 along the longitudinal direction as shown in FIG.

FIG. 4 is a perspective view of the flexible perforated plastic sheet 1 in which the intersection of the first and second direction ribs 2 and 3 forms a woven appearance similar to a twill weave, and the perforations 4 are formed. The state of being defined is shown.

The sheet 1 is made of a flexible thermoplastic sheet, for example, the sheet 1 has a thickness of 10 to 80 μm, and the first and second direction ribs 2 and 3 have a width of 0.15 to 5.
0.7mm, the number of ribs is 20-90 / 25.4mm
Within the range. By appropriately determining the size of the openings 4 and the opening area ratio within this range, it is possible to impart a predetermined liquid permeability to the sheet 1. The sheet 1 has ridges 7 and 8 on which ribs 2 and 3 having a hollow cross section are scattered.
By undulating between them, it has a complicated uneven surface, and light is diffusely reflected on this surface so that it is less glossy than the plastic sheet of the material. Further, when the sheet comes into contact with the skin, the raised portions 7 and 8 make it difficult for the sheet to come into close contact with the skin, and the sticky touch peculiar to the plastic sheet becomes poor. The sheet 1 is used so that the raised portions 7 and 8 come into contact with the skin, and is a liquid-permeable material for covering an absorbent body that absorbs and holds body fluid in a body fluid treatment article such as a sanitary napkin or a disposable diaper. It is particularly suitable for use as a topsheet.

Area 20 of sheet 1 shown in FIGS. 1 and 4.
In the first direction ribs 2A, 2B and the second direction ribs 3
A and 3B define the opening 4A, and the first direction ribs 2A and 2B
B and the second direction ribs 3B and 3C define an opening 4B. In addition, the first direction ribs 2A and 2B and the second direction rib 3
A and 3C define a large opening 21 including the openings 4A and 4B. In other words, the large opening 21 is partitioned below by the rib 3C into two small openings 4A and 4B. When the sheet 1 is used as the liquid permeable surface sheet, the large opening 21 has an excellent effect.
For example, since the opening 21 has a large mouth, it is convenient to take in a large amount of body fluid at one time, and since the lower portion has a small hole, it is possible to prevent backflow of body fluid from the absorbent body. Further, the larger the opening 21, the more easily it is deformed by receiving body pressure, and the opening may become smaller with the deformation. However, the rib 3C can prevent such deformation, and other ribs can be prevented. It is located below 2A, 2B, 3B, and 3D, and the rib 3C does not increase the contact area of the sheet 1 with the skin.

FIG. 5 is a schematic view of a process for continuously producing the sheet 1. Flexible thermoplastic sheet 100 of material
Is a rotary drum 103 having a wire mesh 102 stretched around its circumference.
The wire mesh of the wire mesh 102 is transferred to the wire mesh, and is heated and softened by the hot air from the hot air blower 104 to imprint the structure of the wire mesh 102 in the suction zone 105. Cooling blower 10
By cooling with cold air from 6 to near room temperature, a flexible perforated plastic sheet 107 having a woven appearance following the structure of a wire mesh is obtained. A widening device 108 can be provided in this step. In this device 108, the sheet after the opening processing is 30 to 200% in the width direction, preferably 50 to 50%.
The woven appearance can be changed by increasing the width by 150% to further increase the size of the aperture 4 or widening the rib interval.

FIG. 6 shows a twill weave wire mesh 102 used in FIG.
It is a top view showing an example. In order to obtain the liquid-permeable surface sheet of a body fluid treatment product, the wire rods 122 and 123 have a wire diameter of 0.
It is preferable to use a wire net having a size of 1 to 2 mm and a number of 10 to 90 wires / 25.4 mm. The wire netting 102 can have different wire diameters and numbers between the vertical and horizontal wire rods 122 and 123, or can use twisted wires for at least a part of the wire rod.

[0026]

In the flexible perforated plastic sheet according to the present invention, the first and second direction ribs whose both sides are bent downward intersect with each other, and one of the ribs is raised at the intersection, and the rib between the raised portions is increased. Since the ribs are respectively undulated, the contact area when touching the skin is reduced, the stickiness is reduced and the touch is improved. At the same time, the surface of this sheet tends to diffusely reflect light due to complicated undulations and unevenness, resulting in poor gloss.

Since the first intersecting portion is continuously present in the second direction rib, the first and second intersecting portions intersect each other.
The openings defined by the direction ribs are large openings, and the openings below the openings are partitioned by the second direction ribs. When the flexible perforated plastic sheet including the perforations of this aspect is used as a surface sheet that covers the absorber of the body fluid treatment product, it is effective in promptly absorbing body fluid and preventing backflow of body fluid.

When the flexible thermoplastic sheet is thermoformed following a twill weave, the flexible perforated plastic sheet according to the present invention can be easily obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a flexible perforated plastic sheet according to the present invention.

2 is a view taken along the line II-II of FIG.

FIG. 3 is a view taken along the line III-III in FIG.

FIG. 4 is a perspective view of a flexible apertured plastic sheet.

FIG. 5 is a schematic view of a manufacturing process.

FIG. 6 is a plan view of the wire mesh.

[Explanation of symbols]

 1 Flexible Opening Plastic Sheet 2, 2A, 2B, 2C First Direction Rib 3, 3A, 3B, 3C Second Direction Rib 4, 4A, 4B Opening 5 First Intersection 6 Second Intersection 7 First Protrusion Part 8 Second raised part 10 Top part 11 Lower edge 12 Top part 13 Lower edge 100 Flexible thermoplastic sheet 102 Wire mesh 122,123 Wire rod 108 Widening device (widening step)

Claims (4)

[Claims] 1. A woven fabric formed by intersecting a plurality of first-direction ribs whose both sides are bent downward along a first direction and a plurality of second-direction ribs whose both sides are bent downward along a second direction. It has an external appearance, and two adjacent ribs in the first direction described above and two adjacent ribs in the second direction intersecting the two first direction ribs define a liquid-permeable opening. The first direction ribs are raised at the first intersecting portion formed by the first direction ribs and the second direction ribs that intersect each other.
While forming a ridge along the direction, the lower edges on both sides of the ridge are connected to the tops of the second direction ribs along the second direction, while the second direction ribs are raised at the second intersecting portion to form the second A ridge along the direction is formed, and lower edges on both sides of the ridge are connected to the tops of the first direction ribs along the first direction, and each of the first direction rib and the second direction rib includes 2 A flexible open-hole plastic sheet in which a predetermined number of first intersecting portions continuous with each other are periodically arranged through a predetermined number of second intersecting portions of 1 or more.
To. 2. The predetermined number of the first intersections is 2 to 5, and the predetermined number of the second intersections is 1 to 5.
The flexible apertured plastic sheet described. 3. A flexible thermoplastic sheet having a thickness of 5 to 80 μm which is softened by heating and has a wire diameter of 0.1 to 2
mm, the number of the wire mesh is 10 to 90 pieces / 25.4 mm, and is placed on a twill weave wire mesh, and is formed under the influence of fluid pressure to follow the structure of the wire mesh and swells and bursts between the wire rods. A method for producing a flexible perforated plastic sheet, characterized in that the sheet is provided with a woven appearance and perforations. 4. The manufacturing method according to claim 3, which includes a step of widening said flexible apertured plastic sheet after said thermoforming step.