JP3429807B2 - Stretchable sheet-like structure and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like structure composed of a composite of an elastic sheet and a non-woven fabric, and more specifically, it has sufficient stretchability and excellent breathability. Therefore, the present invention relates to a sheet-like structure that can be advantageously used as a stretchable material used in contact with the body, particularly for sanitary products and diapers, and a method for producing such a sheet-like structure.

[0002]

2. Description of the Related Art Disposable diapers, elastic bandages, surgical gowns and the like are desired to be made of a liquid-impermeable material which does not allow the passage of liquid. Further, since these articles are used in a form of directly contacting with or covering at least a part of the human body, they have a large elasticity required to fit the body and follow its movement. Is desired. Based on these requirements,
A composite sheet in which a non-woven fabric is attached to a stretchable sheet-shaped material such as natural rubber, synthetic rubber or urethane resin has been developed (for example, US Pat. No. 5,167,897).

[0003]

However, it is common knowledge that the elastic sheet used for the stretchable composite sheet as described above is essentially impermeable to air. Therefore, the composite sheet is not breathable. It has the serious flaw of not having. For example, when such a composite sheet is used as a material of a part that comes into contact with the skin in an absorbent product such as a disposable diaper, good feel and waterproofness are satisfied, but disadvantageous due to lack of breathability, mainly stuffy. It is unavoidable to give the user discomfort.

That is, in the prior art, it is common knowledge that a sheet material having excellent liquid impermeability has little or no air permeability.

[0005]

According to the present invention, a thermocompression-bondable elastic sheet is provided, and a non-woven fabric is bonded to at least one surface of the elastic sheet by thermocompression bonding at a joint portion having an arbitrary pattern. Provided is a breathable sheet-like structure, wherein the joint portion has a large number of vent holes formed so as to penetrate the elastic sheet and the nonwoven fabric.

In the sheet-like structure of the present invention having such a structure, even if the elastic sheet does not have air permeability at all, it is formed here at the joint portion between the elastic sheet and the nonwoven fabric. Since it allows air to flow through the ventilation holes, it exhibits breathability as a whole. For this reason, this sheet-like structure exhibits sufficient stretchability and breathability when used in sanitary products, diapers, etc. Give a feeling.

The present invention also provides a method for producing a stretchable sheet-like structure having the above structure. In this method, a non-woven fabric is laminated on at least one surface of a thermocompression-bondable elastic sheet, and the elastic sheet and the non-woven fabric are thermocompression-bonded by pressing two thermocompression-bonding devices facing each other at a joint portion of an arbitrary pattern. In the method for producing a sheet-like structure by doing so, a member having a large number of micro-projections is used as at least one of the thermocompression bonding equipment, and when the thermocompression bonding equipment is crimped with the other thermocompression bonding equipment, Micro vents are formed in the elastic sheet by micro projections.

According to this method, since the through holes are formed in the elastic sheet at the joint portion, even if the elastic sheet does not have air permeability at all, sufficient air permeability is exhibited in practical use.

When thermocompression bonding is performed using a thermocompression bonding device having a large number of microprotrusions, since the microprotrusions are heated to a high temperature, that is, the softening point of the elastic sheet or higher, the microprotrusions penetrate. At this time, the material forming the elastic sheet is moved around the minute protrusions, and an annular thick portion is formed at the periphery of the hole formed after the minute protrusions are separated. This thick portion has a reinforcing effect of compensating for the strength reduction of the elastic sheet due to the formation of the holes, and strengthens the bond with the non-woven fabric. In some cases, it is possible to bond the elastic sheet and the non-woven fabric only to this thick portion.

In the present invention, the thermocompression bonding of the elastic sheet and the non-woven fabric may be performed uniformly over the entire region to be bonded, but may be performed in any pattern such as a mesh shape, a satin shape, or a linear shape. It is also possible to do it partially. Such partial thermocompression bonding can be easily performed by providing a concave portion or a convex portion in a desired pattern on at least one of two opposing thermocompression bonding equipments, and flattening the entire joint surface. In some cases, it is easier to obtain a uniform bond as compared with the case of thermocompression bonding.

The thermocompression-bondable elastic sheet advantageously used in the present invention is a film-like or a thermocompression-bondable material such as synthetic rubber, polyurethane, styrene-butadiene block polymer, or polyolefin elastomer. All non-woven elastic sheets can be mentioned. Especially preferred materials are EVA, ultra low density LLDPE,
Polyolefin elastomer such as ethylene / propylene elastomer and ethylene / methyl acrylate elastomer alone or synthetic rubber thereof, styrene ethylene butadiene / styrene block polymer (SEBS)
Blended with or polyurethane-based elastomer,
It is in the form of a film or a non-woven fabric formed by coextrusion with a polyolefin-based elastomer. It is desirable that these elastic sheets are uniaxially or biaxially stretched after molding.

The non-woven fabric used in the present invention may be any kind of non-woven fabric as long as it is suitable for the purpose of the sheet-like structure, but a non-woven fabric obtained by binding parallel card webs by a high-pressure water stream, or a filament. A spunbonded non-woven fabric obtained by weaving or tows is a particularly preferable non-woven fabric because the fibers are relatively oriented in the machine direction and therefore the degree of extension in the cross-machine direction is significantly larger than that in the machine direction. . Among them, the non-woven fabric obtained by the hydroentangling method is a non-woven fabric having high elongation and high strength and tenacity, and is suitable for use in the present invention. Further, as the raw material fibers of the non-woven fabric, PE, PP and PET which are hydrophobic fibers having low water wettability, low irritation to the skin and high safety
Etc., 1.5d-3d synthetic fiber staples are preferred.

The non-woven fabric may be provided on only one side of the elastic sheet, but may be provided on both sides as required. Alternatively, two elastic sheets each provided with a non-woven fabric on one side may be superposed to form a single sheet structure. Such a composite having a nonwoven fabric on both sides is optimal as a material for forming the main body of a disposable diaper, for example.

Embodiments of the present invention will be described below with reference to the drawings.

[0015]

1 is a plan view showing an example of a sheet-like structure constructed according to the present invention, and FIG. 2 is an enlarged sectional view taken along the line AA of FIG. In the figure, the elastic sheet 11 and the non-woven fabric 12 constituting the sheet-shaped structure 10 of the present invention are overlapped with each other and bonded by thermocompression bonding at a plurality of strip-shaped joints 13 extending in parallel with each other. Vent holes 14 are formed in each of the coupling portions 13 and are arranged in one row at equal intervals in the central portion in the width direction. The vent hole 14 is formed by the elastic sheet 11 and the nonwoven fabric 1.
It penetrates 2.

The elastic sheet 11 used in this example is EV
The nonwoven fabric 12 is made of A and is made of polyethylene staple of 1.5d to 3d by the hydroentangling method. And a vent hole 14 formed in the joint portion 13.
Is approximately circular with a diameter of about 0.5 mm , and the distance between adjacent vent holes is about 1 mm.

The sheet-like structure 1 having such a structure
0 is expandable within the range of elasticity of the non-woven fabric 12 having low elasticity, and at the same time, the ventilation holes 14 formed in the joint portion 13
Demonstrate a sufficiently large breathability through. Therefore, the sheet-like structure 10 is applied to an article used in contact with the body, such as a sanitary product or a diaper, and gives a comfortable feeling of use due to good fit and breathability.

FIG. 3 shows a sheet-like structure according to another embodiment of the present invention. In the sheet-shaped structure 20, the width of the nonwoven fabric 12 is larger than the width of the elastic sheet 11 between the adjoining coupling portions 13 and 13, so that the channel 15 is formed between the elastic sheet 11 and the nonwoven fabric 12. 1 shows a sheet-shaped structure 10. Such a sheet-like structure 10 can be obtained by thermocompression bonding the nonwoven fabric 12 between the two adjacent bonding portions 13, 13 with the bonding portion 13 in a slackened state. .

Alternatively, after connecting the elastic sheet 11 and the nonwoven fabric 12 in the state shown in FIGS.
It can also be obtained by stretching the non-woven fabric 12 by stretching it in the direction orthogonal to the length direction of the non-woven fabric to a length within the elastic limit of the elastic sheet 11 and beyond the elastic limit of the non-woven fabric 13 and then opening.

The sheet-like structure having the folds of the non-woven fabric 12 as shown in FIG. 3 is further improved in the soft and soft feeling of the non-woven fabric 12 and can be particularly advantageously applied to various sanitary products.

Further, in the present invention, the sheet-like structure is provided with the non-woven fabric 12 only on one surface of the elastic sheet 11 as shown in FIG. 1, and also the non-woven fabrics 12A and 12B are provided on both sides as shown in FIG. It is also possible to use a sheet-like structure 30 having a sandwich structure provided respectively. The sheet-like structure 30 of this structure is a nonwoven fabric 1 having pleats.
Since 2A and 12B are located on both sides, it is particularly suitable as a material for disposable diapers for infants.

Next, a method for producing the sheet-shaped structure of the present invention will be described.

FIG. 5 shows an example of thermocompression bonding equipment used to manufacture the sheet-like structure 10 of FIG.
The thermocompression bonding equipment comprises a pair of rolls 21 and 22 arranged in parallel to each other, and the first roll 21 is provided with a plurality of annular projections 23 having a trapezoidal cross section on its peripheral surface.
An annular protrusion 24 is provided on the second roll 22 so as to face the annular protrusion 23 provided on the first roll 21.

As shown in more detail in FIG. 6, a large number of minute projections 25 are formed on the outer peripheral surface of the annular projection 23 of the first roll 21 at predetermined intervals, and the annular projection of the second roll 22 is formed. On the outer peripheral surface of 24, a recess 26 corresponding to the minute projection 25 is formed. The first and second rolls 21 and 22 are biased so that the annular projections 23 and 24 are pressed against each other at a predetermined pressure, and in this state, they are synchronously rotated in opposite directions. . The first and second rolls 21 and 22 are heated by heating means (not shown) so that the upper surfaces of the annular protrusions 23 and 24 reach a temperature suitable for thermocompression bonding.

The thermocompression bonding operation is performed by feeding the elastic sheet and the non-woven fabric in a state of being superposed on each other between the first roll 21 and the second roll 22. By this operation, the annular protrusions 23 and 24 facing each other are thermocompression-bonded to form the joint portion 13, and at the same time the minute protrusions 25 are formed.
By the action of the concave portion 26, the vent hole 14 is formed in the joint portion 13.

When a roll having an appropriate elasticity is used as the second roll arranged opposite to the first roll 21 having a large number of minute projections 25 provided on the upper surface of the annular projection 23, the concave portion is It is possible to omit 26.

(Example) Elastic sheet 11 and nonwoven fabric 1
The following materials were used as 2, and a sheet-like structure having the structure shown in FIG. 1 was produced.

Elastic sheet: 40 μm thick perforated EDPM film nonwoven fabric: Polypropylene spunlace, 30 g /
m ² Each connecting portion 13 has a width of about 2 mm and has a width of about 2.5 mm.
Formed by thermocompression. The thermocompression bonding uses the rolls 21 and 22 shown in FIG.
With the peripheral speed of about 10 m / min. And the elastic sheet and the non-woven fabric are continuously fed between the rolls 21 and 22. The pressing force between the rolls was adjusted so that the pressure was 1.0 kg / cm ² .

The air permeability of the joint portion of the obtained sheet-like structure was 50 sec / 100 cc, which showed good air permeability.

[0030]

As described above, the breathable sheet-like structure of the present invention comprises at least one surface of the elastic sheet, and a nonwoven fabric bonded by thermocompression bonding at the bonding portion of a desired pattern, This elastic sheet has a large number of ventilation holes corresponding to the convex portions of the non-woven fabric at the joint portion. Therefore, the elastic sheet has a large breathability as a whole and is flexible on the non-woven fabric side. Therefore, it is most suitable for various products used especially in contact with the skin, such as sanitary napkins and disposable diapers.

[Brief description of drawings]

FIG. 1 is a plan view showing a part of a sheet-like structure according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view of a sheet-like structure according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a sheet-shaped structure according to still another embodiment of the present invention.

FIG. 5 is a partial side view showing a thermocompression bonding equipment used for manufacturing the sheet-shaped structure of the present invention.

6 is a partially enlarged cross-sectional view of the thermocompression bonding equipment of FIG.

[Explanation of symbols]

10 Sheet-like structure 11 elastic body 12,12A, 12B Nonwoven fabric 13 Connection 14 vents 15 channels 21,22 rolls 23, 24 annular protrusion 25 minute protrusions 26 recess

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 A61F 13/00-13/84

Claims (6)

(57) [Claims] 1. A thermocompression-bondable elastic sheet, and a nonwoven fabric bonded to at least one surface of the elastic sheet by thermocompression bonding at a bonding portion having an arbitrary pattern, and the elastic sheet and the elastic sheet at the bonding portion. A breathable sheet-like structure having a large number of vent holes formed so as to penetrate the nonwoven fabric. 2. The sheet-shaped structure according to claim 1, wherein the elastic sheet has a ring-shaped thick portion at a peripheral portion of the ventilation hole. 3. The sheet-shaped structure according to claim 1, wherein a channel-shaped space is formed between the elastic sheet and the non-woven fabric in a portion other than the joint portion. 4. The connecting portion and the portion other than the connecting portion
Any one of Claims 1-3 arrange | positioned in multiple rows by turns.
The sheet-shaped structure according to item 1. 5. overlapped nonwoven fabric on at least one surface of the thermocompression bonding resilient sheet, the elastic sheet and the nonwoven fabric, and at the junction of any pattern, by crimping the two thermocompression bonding equipment opposing heat In the method for producing a sheet-like structure by crimping, a member having a large number of microprojections is used as at least one of the thermocompression bonding equipment, and when this thermocompression bonding equipment is crimped with the other thermocompression bonding equipment. A method of manufacturing a stretchable sheet-like structure, characterized in that minute vent holes are formed in the elastic sheet by the minute projections. 6. After the thermocompression bonding, the nonwoven fabric is stretched in a direction substantially orthogonal to the joint portion to cause permanent elongation of the nonwoven fabric, thereby forming a channel-shaped space between the elastic sheet and the nonwoven fabric. The method of claim 5, wherein the method comprises forming.