JPH03151970A - disposable diapers - Google Patents

Abstract

PURPOSE:To make cutting operation easy and to attempt to improve productivity by adhering and fixing an expansion elastic body consisting of a urethane foam sheet in a bag-shaped part formed by folding back an apex of the second flap and specifying a dynamic coefficient of friction of a hydrophobic non-woven fabric to the urethane foam sheet. CONSTITUTION:The title diaper has an absorbing body 7 between a liq.- permeable surface sheet 4 and a liq.-impermeable rear sheet 6, side flaps extending outside from both side edge parts in the transverse direction of the absorbing body 7 and the second flaps 2 consisting of a hydrophobic non-woven fabric 1 each of which has a base end 5 on each side flap and extends above it. In addition, each apex of the second flaps 2 is folded back to form a bag- shaped part, wherein an expansion elastic body 3 consisting of a urethane foam sheet is adhered and fixed. In this case, as the dynamic coefficient of friction of the hydrophobic non-woven fabric 1 to the urethane foam sheet 3 is made 3.5 or smaller, when a continuous laminated body is cut between the absorbing bodies, the urethane foam sheet 3 slides well in the bag-shaped part of the surface sheet 6 and no tensile force on the end part of the bag-shaped part in the central direction of a diaper is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to disposable diapers. More specifically, the present invention relates to a disposable diaper that prevents leakage, stuffiness, and rashes and has good productivity.

[Conventional technology]

Conventionally, disposable diapers include an absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, and
Disposable diapers are known in which three-dimensional membrane gears (second flaps) are attached along both side edges of an absorbent body in order to improve stuffiness and leakage.

The usual way to install gears is to sandwich an absorbent material cut to the size of one diaper between a continuous top sheet and a continuous back sheet at regular intervals in the flow direction of both sheets, and then A continuous stretchable elastic body is sandwiched in a stretched state on both sides of the absorbent body, and the stretchable elastic body is placed between the top sheet and back sheet at both side edges of the absorbent body so that it is not glued to the back and abdomen at the longitudinal ends of the diaper. Bonded to form a continuous laminate and then cut transversely between the absorbents to create individual diapers.

At this time, the portion of the stretchable elastic body that is not bonded to the top sheet and back sheet loses its tension at the same time as it is cut, so it slides between the top sheet and back sheet and is pulled back toward the center of the diaper.

A similar manufacturing method is also common for diapers with three-dimensional crotch gears, and in this case, a step of wrapping the stretchable elastic body in a bag shape with a part of the top sheet is added. The portions of the stretchable elastic topsheet that are not adhered to the pouch (back and belly portions) lose tension at the same time as they are cut, so they slide within the pouch of the topsheet and are pulled back toward the center of the diaper.

Stretchable elastic bodies include rubber thread, elastic multifilament,
Urethane film, urethane foam, etc. are used, but urethane foam is the best in terms of texture.

However, among these stretchable elastic materials, urethane foam has the highest coefficient of friction;
Due to conditions such as the shape of a part of the three-dimensional gear cutter, it does not slide properly inside the bag-shaped part of the top sheet after cutting, and the product is completed with both ends of the bag-shaped part of the top sheet being pulled toward the center of the diaper, resulting in the product losing its shape. occurs and becomes a problem.

As a countermeasure to this problem, a method has been proposed in which the front side of the continuous stretchable elastic body is cut to a predetermined length, and the stretched state is glued to the position corresponding to the bag-shaped part of the continuous topsheet, but this method is not productive. There is a drawback that it is not good.

[Problem that the invention seeks to solve]

In the production of disposable diapers with three-dimensional crotch gears using urethane foam as the stretchable elastic body, when the continuous laminate is cut between the absorbers, the urethane foam top sheet is not adhered to the inside of the bag-shaped portion. The purpose of the present invention is to solve this problem because the parts do not slide properly and both ends of the bag-like part of the top sheet are pulled toward the center of the diaper together with the urethane foam, making it impossible to produce a normal product. shall be.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present inventors have conducted intensive research and have completed the present invention.

The present invention has an absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, and has side flaps extending outward from both lateral edges of the absorbent body, and A second fabric made of a hydrophobic nonwoven fabric whose base end is on the side flap and extends upward in the longitudinal direction of the side edge of the absorbent body.
In the disposable diaper having a flap, the tip of the second flap is folded back to form a bag-like part, and a stretchable elastic body made of a urethane foam sheet is adhesively fixed within the bag-like part, and the hydrophobic This disposable diaper is characterized in that the coefficient of dynamic friction of the nonwoven fabric with respect to the 7-ohm urethane sheet is 3.5 or less.

The coefficient of dynamic friction is measured by the following method.

The nonwoven fabric to be measured is 70 m in the flow direction and 50 m in the 1] direction.
Cut it to a size of m and paste it on the sample table with the measurement side facing up.

One side of a 10g rectangular parallelepiped weight (the size of that side is 25I)
III
The Il1m side and the 25th side of the urethane foam are attached in the same direction, and the urethane foam that extends along the 17 inch side of the weight is folded back along the side of the weight.

Align the flow direction of the urethane foam (flow direction during diaper production) with the flow direction of the nonwoven fabric attached to the sample table (flow direction during diaper production), and stack the urethane foam on the nonwoven fabric together with the weight. . A weight and a load cell for detecting the number of layers are tied with a thread, and the load cell is pulled horizontally in the flow direction of each material at a speed of 50 mm/min, and the slip resistance value W (g) is calculated according to JIS P8147.

Then, the dynamic friction coefficient A is calculated using the following formula.

A=W/I O The present invention will be explained in detail below.

FIG. 1 is a perspective view of the disposable diaper of the present invention, and FIGS. 2, 3, and 4 are cross sections taken along the x-X line, Y-Y line, and Z-Z line in FIG. 1, respectively. Show the diagram.

In the drawings, reference numeral 1 indicates a hydrophobic nonwoven fabric sheet, 2 indicates a second flap part (leakproof part), 3 indicates a stretchable elastic body made of a urethane foam sheet, 4 indicates a top sheet (hydrophilic nonwoven fabric),
Reference numeral 5 indicates the proximal end of the bag-like part (leakproof part), 6 indicates the back sheet, and 7 indicates the absorbent body.

First, an example of a method for manufacturing a disposable diaper with a leak prevention part (three-dimensional membrane gears) 2 will be described.

Two continuous hydrophobic nonwoven fabric sheets having a coefficient of friction of 3.5 or less with the urethane foam sheet are prepared.

A hot melt adhesive having a predetermined width is intermittently applied to a predetermined position inside each of the two continuous hydrophobic nonwoven fabric sheets so that the hot melt adhesive is at the same position in the flow direction of the two hydrophobic sheets.

Next, continuous urethane foams 3 of a predetermined width are pasted together in a stretched state at the hot-melt adhesive application position, and a bag-like portion is created by folding the urethane foams inward at the center lines of each urethane foam.

On the other hand, a predetermined width of hot melt adhesive is applied to both side edges of the portion corresponding to the dorsal side and ventral side of the continuous surface nonwoven fabric sheet 4, and the above continuous hydrophobic nonwoven fabric is applied to both side edges of the surface nonwoven fabric sheet. The portion of the continuous hydrophobic nonwoven fabric sheet to which the urethane foam sheet is not bonded to the proximal end 5 of the double-folded bag-like portion of the sheet coincides with the hot melt adhesive application position of the continuous surface nonwoven fabric sheet. Layer them like this and glue them in a linear manner to form a top sheet.

Next, the top sheet 4, the absorbent body 7 cut to the size of one diaper, and the back sheet 6 are separated at regular intervals in the flow direction of the absorbent body, and then the continuous hydrophobic nonwoven fabric of the top sheet is The sheets are pasted together so that the bonded parts of the sheet and the urethane foam are located on both side edges of the absorbent body to form a continuous laminate. Cut to form individual diapers.

In this case, if the inner surface of the bag-like part of the top sheet has a coefficient of dynamic friction of 3.5 or less with the urethane foam sheet, when the continuous laminate is cut between the absorbers, the bag-like part of the top sheet will The unadhered urethane foam sheet slides smoothly inside the pouch, and no pulling force is generated at the end of the pouch toward the center of the diaper.

The top sheet, back sheet, absorbent body, etc. mentioned here are all commonly used.

A nonwoven fabric having a coefficient of dynamic friction with the urethane foam sheet of 3.5 or less can be easily obtained by selecting raw material fibers. Further, it is preferable to suppress fuzz on the surface of the nonwoven fabric.

In addition, the degree of elongation when adhering the urethane foam sheet to the bag-like part is 50 to 3, taking into account the amount of penetration into the skin when worn.
It is preferable to set it within the range of 00%.

The urethane foam sheet may be fixed inside the bag in a flat manner as shown in 3 in Figure 3, but it is better to attach it in an inverted U-shape so that it is in close contact with the nonwoven fabric for better leakage prevention effect. The skin feels soft and good. The urethane foam sheet is preferably as thin as possible from the viewpoint of leak-proofing properties and feel. Usually 10~40II1m width and several mm
It is preferable to have a thickness of .

〔Effect of the invention〕

According to the present invention, a disposable diaper with three-dimensional membrane gears (second flap) using urethane foam can be easily produced at high speed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the disposable diaper of the present invention, and FIGS. 2, 3, and 4 are taken along the XX line, YY line, and Z line of FIG.
-A cross-sectional view taken along the Z line is shown. ■ - Hydrophobic nonwoven fabric sheet 2 - Second flap part (leakproof part) 3 - Stretchable elastic body 4 ... Top sheet 5 - Base end part 6 - Back sheet 7 - Absorbent body

Claims (1)

[Claims] 1. an absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, side flaps extending outward from both lateral edges of the absorbent body; In a disposable diaper having a second flap made of a hydrophobic nonwoven fabric that extends upward from the side flap in the longitudinal direction of the side edge, the tip of the second flap is folded back to form a bag-shaped part. and a stretchable elastic body made of a urethane foam sheet is adhesively fixed in the bag-like part, and the coefficient of dynamic friction of the hydrophobic nonwoven fabric with respect to the urethane foam sheet is 3.5 or less. Diapers.