JPS62156948A - Waterproof adsorption sheet and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a waterproof adsorption sheet used for sanitary products, disposable diapers, etc., and a method for manufacturing the same.

(Prior art) Conventionally, waterproof adsorbent sheets used for this type of applications, which require adsorption functions as well as waterproof functions, have been made from combinations of specific synthetic fibers such as polyethylene-polypropylene-polyester as sheet-like base materials. A synthetic resin with a relatively low melting point, such as polyethylene, ethylene-vinyl acetate copolymer resin, or ionomer resin, is extruded onto one side of the non-woven fabric or pulp-based non-woven fabric in a molten state using the so-called T-die method. It is known that a synthetic resin sheet is uniformly laminated over the entire surface of one side of a sheet-like base material, which is then pressed and cooled using a combination of nip rolls and cooling rolls.

(Problem to be Solved by the Invention) However, in such a waterproof adsorption sheet, even if a nonwoven fabric with good adsorption properties is used for the sheet-like base material, the molten synthetic resin will not be applied to the entire surface of the base material between the nip roll and the cooling roll. i to
I-transparent and uniform crimping over the entire surface significantly destroys or reduces the voids formed in the nonwoven fabric, which not only significantly reduces the liquid adsorption ability but also has the drawback of extremely poor texture. Ta.

The present invention was made in view of the drawbacks of the conventional waterproof adsorbent sheets, and an object of the present invention is to provide a waterproof adsorbent sheet in which the adsorption properties of the base material itself are hardly 10%, and a method for manufacturing the same.

(Means for Solving the Problems) Zunawa, the present invention provides a waterproof material in which a synthetic resin sheet coated on one side of a sheet-like base material having adsorption properties is fused at partial joints. An adsorption sheet and its manufacturing method.

In the present invention, the adsorbent sheet-like base material is polyethylene-polypropylene, which is conventionally used.
Sheet-like base materials with high liquid body centering properties, such as non-woven fabrics made of synthetic fibers such as polyester or pulp-based non-woven fabrics, can be used in the same way. As for the material, conventionally used thermoplastic synthetic resins such as polyethylene, ethylene-vinyl acetate copolymer resin, and ionomer resin, which have a relatively low melting point and low water absorption, can be similarly used.

Further, in the sheet of the present invention, one side of the sheet-like base material must be fused at a partial joining point to a synthetic resin sheet that covers the entire surface of the base material.

Welding at such partial joining points can be performed using any welding means that can bond the base sheet and synthetic resin sheet together without impairing the adsorption properties of the base material itself. Any fused shape may be used. FIGS. 1A to 1C show an example of a synthetic resin sheet fused to a base sheet.

In other words, Fig. 1(A) shows the case where the fusion is performed in a linear manner at regular intervals, Fig. 1(B) shows the case where the fusion is performed in a lattice pattern, and Fig. 1(C) shows the case where the fusion is performed in a grid pattern. This shows a case where fusion is performed in approximately uniformly distributed dots. In the figure, a,
b and c indicate the fused portions, respectively. In addition, although not shown,
It can take an appropriate joined shape such as wavy shape or band shape.

Next, a method for manufacturing the waterproof adsorption sheet of the present invention will be explained.

Figure 2 shows a schematic diagram of the manufacturing process, where ■ is an extruder,
3 is a die plate, 3 is a T die provided on the die plate 2, 4 is a nip roll, 5 is a cooling roll that rotates in contact with the nip roll 4, 6 is a sheet-like base material feeding roll, 7 is a product winding roll, 8 is a sheet 9 is a sheet of the present invention.

In the figure, in manufacturing the sheet of the present invention, a special process is performed to partially form convex portions on the surface of the nip roll 4. As means for this special processing, (a) the roll surface made of resin such as silicone rubber is molded into a surface having protrusions in the shape as shown in FIG. A cloth or mesh woven into a suitable pattern using glass fibers coated with a resin such as fbl tetrafluoroethylene is wrapped around a flat roll surface. (It is possible to take measures such as wrapping a resin tape such as Cl tetrafluoroethylene around the roll surface at regular intervals.

A sheet-like base material 8 is fed out from a feed roll 6 and sent to a nip gap 10 between a specially processed nip roll 4 and a cooling roll 5 by means such as described above. The synthetic resin is extruded into a film from the T-die 3 and coated on the sheet-like base material 8 on the nip rolls 4 . Next, the sheet-like base material 8 is pressurized while passing through the nip between the nip roll 4 and the cooling roll 5.
is fused to one side of the

In this case, according to the method of the present invention, the crimping by the nip roll 4 is performed only on the convex portions partially formed on the surface of the nip roll, so that the base material 8 other than the crimped portion is
is prevented from being pressurized or fused with the coated synthetic resin sheet.

The crimped sheet is then cooled on the surface of the cooling roll 5, and then wound up by the winding roll 7 to form a product. FIG. 3 shows a perspective view of an example of a waterproof adsorption sheet manufactured according to the present invention. In the figure, 8 is a sheet-like base material;
Reference numeral 11 denotes a synthetic resin sheet that is fused to the sheet-like base material 8 at partial joints.

(Example) As a sheet-like base material, basis weight 18 g/rd, tensile strength vertical 1800 g/25 mm, width 400 g/251
On the other hand, an ionomer resin was used as the synthetic resin for fusing, and a cloth woven with tetrafluoroethylene-coated glass thread was wrapped around the nip roll, and the nonwoven fabric was coated with the resin to a thickness of 20 μm using the method described above. The sheet of the present invention was manufactured by pressure bonding.

The obtained sheet has a basis weight of 3 B g / rd and a tensile strength of 200.1 g / 25 vs ■, and because the fusion between the nonwoven fabric and the resin is not uniform over the entire surface, the unique texture of the nonwoven fabric is not impaired, and it has excellent liquid adsorption. It was a waterproof sheet with excellent properties.

(Effects of the Invention) As explained in detail above, the waterproof adsorption sheet of the present invention has the following features:
Since the synthetic resin sheet coated on one side of the adsorbent sheet-like base material is fused together at partial joints, the voids that constitute the main factor of the liquid adsorption property of the base sheet are During pressurized welding of the resin, there is no blockage caused by the molten resin, and therefore the liquid adsorption properties are hardly inhibited. On the other hand, a sheet with excellent waterproof properties can be obtained by appropriately selecting and adjusting the material, thickness, etc. of the synthetic resin sheet coated on one side of the sheet-like base material. The waterproof adsorption sheet of the present invention thus obtained has excellent both waterproofness and adsorption properties, and therefore,
It is suitable for use in sanitary products, disposable diapers, etc., and its manufacturing method requires only slight improvements to conventional manufacturing methods, so it has the advantage of not increasing costs. be.

[Brief explanation of drawings]

Figures 1 (A), (B), and (C) are examples of the convex shape formed on the surface of the nip roll in the production of the present invention, Figure 2 is a manufacturing process diagram of the present invention, and Figure 3 is the production process of the present invention. FIG. 2 is a perspective view of a waterproof adsorption sheet. DESCRIPTION OF SYMBOLS 1... Extruder, 3... T-die, 4... Nip roll, 5... Cooling roll, 8... Sheet-like base material, 9...
... Sheet of the present invention, 10... Nip gap, 11...
Synthetic resin sheet.

Claims (2)

[Claims] (1) A waterproof adsorbent sheet made of a synthetic resin sheet coated on one side of an adsorbent sheet-like base material and fused together at partial joints. (2) A nip roll and a cooling roll are formed by extruding a sheet of molten synthetic resin onto one side of a continuously fed sheet-like adsorbent base material, overlapping it, rotating in contact with each other, and forming partial convex portions on the surface. A method for manufacturing a waterproof adsorption sheet, characterized by passing it through a nip gap and fusing it under pressure.