JPH0563180B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an elastic fastening tape, more specifically, a fastening tape that is elastic, soft and firm, and is particularly effective as a fastening tape for disposable diapers. This is related to fastening tape.

[Conventional technology]

Conventional adhesive tapes include paper, film, non-woven fabric,
Generally, the tape base material is a single material or a composite material such as cloth, and an adhesive is applied to the tape base material, and these tapes do not have elasticity.

In addition, as a tape having elasticity, for example, in Japanese Patent Application Laid-open No. 51-68345 and Japanese Utility Model Application No. 57-157209, there is a tape for disposable diapers in which an elastic ring or band-like elastic body is arranged in the center of the tape. Proposed.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional general tape base material is not suitable for uses that require or are preferably stretchable, such as disposable diapers.

In addition, all the proposals described in the above-mentioned publications have a structure in which stress is concentrated in the boundary area between the elastic body and the inelastic body. There are problems in terms of practical application, such as reduced productivity.

That is, in the tape fastener described in JP-A-51-68345, the elastic body at the center of the tape has a ring shape, so when it is attached to the surface of an adherend during use, the tape made of an inelastic body When the elastic ring is stretched by grasping its end, a dogleg-shaped deformation occurs due to stress concentration in the boundary area between the elastic ring and the inelastic body, causing the surface of the inelastic body to adhere to the adherend surface. This greatly reduces the adhesion area, resulting in a decrease in adhesive properties, and also tends to cause the inelastic body to break.

On the other hand, Japanese Utility Model Application Publication No. 57-157209 proposes a tape structure in which an inelastic body is bonded to the back surface of both ends of a band-shaped elastic body. However, with such a structure, the bonded portion of the elastic and inelastic materials curls during tape processing, significantly reducing productivity, and the entire surface of the tape is not pressed thoroughly during use. However, it is not possible to ensure a sufficient bonding area and therefore adhesive strength, and the tape 31 tends to peel off from the adherend 30 as shown in FIG. 4 due to the force of the tape trying to restore the curl even after bonding. (32 in the upper part of FIG. 4 shows the boundary area between the elastic body and the inelastic body of the tape 31, and 33 shows the adhesive layer). Furthermore, the difference in thickness in the thickness direction between the elastic material-only portion and the non-elastic material bonded portion significantly impedes tape processing workability.

Regarding elastic tapes that do not have a step in the thickness direction between the elastic and inelastic parts, there is only an abstract description of the possibility in Japanese Utility Model Application Publication No. 57-157209, but there is no concrete description. No technical details have been disclosed.

[Means for solving problems]

The present invention was made as a result of intensive studies with the aim of providing a tape base material that solved the above-mentioned problems. In order to prevent the physical properties of the boundary area of the inelastic body from discontinuously and abruptly changing, the boundary area is formed by using a mixture of both elastic and inelastic materials. It is constructed so that the stress applied to it is dispersed.

That is, the present invention provides at least two non-elastic parts of a tape base material configured by integrally bonding a central part made of an elastic material and two end parts made of an inelastic material via a boundary region, respectively. An elastic body, characterized in that an adhesive layer is provided on the same side of the body, and the boundary region is formed by mixing and integrating the elastic body-forming material and the inelastic body-forming material. The above object has been achieved by providing a fastening tape that has the following properties.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The elastic fastening tape of the present invention having the above features will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is an enlarged cross-sectional view showing one embodiment of the elastic fastening tape of the present invention.
1 is a central part made of an elastic body, 2, 2 are end parts made of an inelastic body, and the central part (elastic body) 1 and both ends (inelastic body) 2, 2 are boundary region parts 3, 2, 2, respectively. 3
The tape base material 10 is configured by being integrally bonded by the tape base material 10. Further, 4, 4 is the tape base material 10
This is an adhesive layer provided on one surface of the above-mentioned inelastic body.

The elastic body 1 may be made of, for example, styrene-ethylene-butadiene-styrene (SEBS), styrene-
It is formed from a styrene elastomer such as butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), or an olefin elastomer such as a polyethylene-polypropylene (PE/PP) copolymer, and is also made of the above-mentioned non-elastic material. 2 and 2 are made of thermoplastic polymers such as polyethylene (PE), polypropylene (PP), polyester (PEs), and polyamide (PA), and are optionally provided with inorganic or organic reinforcing materials, Fillers, colorants, etc. can be used in combination. In addition, as described later, depending on the molding method,
Polymers with crosslinkable unsaturated bonds are used to mold the elastic body.

In the present invention, the above-mentioned elastic body is one that has a property called rubber elasticity, which deforms when stress is applied but recovers its shape when stress is removed. The above-mentioned elastic body 1 and the above-mentioned inelastic body 2,
2 is formed by selecting each of these materials so that the elastic modulus of the inelastic body is preferably 1.5 times or more, more preferably 3 times or more, that of the elastic body. The preferable tensile modulus of the elastic body varies depending on the use of the fastening tape, but when used for disposable diapers, it is preferably 5 to 500 kg/cm ² .

Further, the boundary regions 3, 3 are formed by mixing and integrating the above-mentioned elastic body-forming material and the above-mentioned inelastic body-forming material. Such mixed integration can be performed by a method such as melting and extruding both or one of the elastic body forming material and the inelastic body forming material, and in this case, the tensile elasticity of the elastic body in the boundary area is The ratio gradually decreases from the inelastic body side to the elastic body side, that is, the closer to the elastic body side the more the elastic body forming material becomes, and the closer to the inelastic body side the more the inelastic body forming material becomes. It is preferable to configure the boundary zone by mixing the two so that the elastic modulus decreases linearly, but it does not necessarily have to be linear. It is sufficient that the body-forming material and the inelastic body-forming material are mixedly integrated. This boundary area 3,
In No. 3, the ratio of the width A of the boundary area (width between the elastic body edge and the non-elastic body edge connected via the boundary area) and the thickness B of the tape base material (A/B ) is preferably 0.2 to 20, more preferably 1 to 10
It is. The thickness of the tape base material 10 is preferably 0.02
-3 mm, more preferably 0.1-1 mm. still,
It is preferable that the thickness of the center portion 1, both end portions 2, 2, and the boundary region portions 3, 3 are the same as shown in FIG. 1, and constitute the tape base material 10 of the same thickness.
In the fastening tape of the present invention, 50
There is no problem even if there is a difference of less than %, preferably less than 20%.

4, 4 are adhesive layers provided on one surface of the same side of both end portions 2, 2, and these adhesive layers 4, 4 are as follows:
It is usually formed by applying an adhesive or adhesive onto both ends 2,2. In addition, the adhesive layer 4,
4 may be provided on the entire surface of the tape base material if necessary, and silicone may be provided on the other surface of the tape base material, especially on the surface of the inelastic body and boundary area, if necessary. It is also possible to provide a back surface treatment layer by coating.

The stretchable fastening tape of the present invention is not limited to the above-mentioned embodiments, nor is the method of molding the same, but it can be molded by the following method.

Two or more types of polymers having different elastic moduli, specifically, polymers each selected from the elastic body-forming material and the inelastic body-forming material, are separately plasticized and fed onto the same roll and rolled; By fusing, that is, by molding a sheet by supplying both polymers while adjusting the supply amount so that both polymers are mixed partially from the interface between the two polymers to the inside, both ends and It is possible to form a tape base material provided with a boundary region portion whose elastic modulus gradually changes continuously between the tape base material and the center portion.

Another method is to use the above-mentioned raw materials and use two extruders, supplying the elastic body-forming material from the first extruder and the inelastic body-forming material from the second extruder into the same die. By doing so, the tape base material can be formed. In this case, the elastic body-forming material is supplied to the center and the inelastic body-forming material is supplied to both ends, and the elastic modulus of the boundary area between the elastic body and the inelastic body in the obtained sheet (tape base material) is continuous. A die designed to change gradually is used. The supply of the polymer constituting the boundary region may be carried out so that either the elastic body or the inelastic body is successively increased/decreased in a layered manner, but when both are kneaded, either one is gradually increased/decreased. It is preferable to supply the material in such a manner that deformation during expansion and contraction and bondability between the elastic body and the inelastic body occur.

Still another method is to use a polymer with a crosslinkable unsaturated bond such as ethylene-propylene-diene methylene crosslinked product (EPDM) as the material for forming the elastic body, and a saturated polymer such as PE or PP as the material for forming the inelastic body. Form the sheet using the method of EB,
By applying UV irradiation to give rubber elasticity to the central part,
Alternatively, a tape base material is formed by adding a crosslinking agent to a polymer having a crosslinkable unsaturated bond such as EPDM used in the central portion, forming a sheet at a temperature below the crosslinking temperature, and processing at a temperature necessary for crosslinking.

Alternatively, a sheet can be formed with a polymer composition such that the crosslinking density is higher at the edges than at the center, and EB,
A sheet is formed by irradiating it with UV or by adding more crosslinking agent to the edges than to the center, and then heat-treated to form the tape base so that the edges are higher.

Next, the stretchable fastening tape of the present invention will be explained with reference to manufacturing examples thereof.

Production Example As shown in Fig. 3, polyethylene (Mitsui Petrochemical Industries, Ltd.)
2020L) was plasticized at 220 degrees, and from the extrusion molding machine 21, a styrene thermoplastic elastomer [Lavalon manufactured by Mitsubishi Yuka Co., Ltd.
MJ4300 (100 parts), calcium carbonate manufactured by Shiroishi Kogyo Co., Ltd., and Ryton BY (30 parts) were preheated and melted and mixed] to form an elastic body 1' which was plasticized at 230°C on three rolls 23. supply and fuse them,
Roll it to a thickness of 0.5 mm and a width of 90 mm as shown in Figure 2.
A tape base material 10 was obtained in which no curl of mm was observed. Both ends of this tape base material 10 (non-elastic body)
Width of 2 and 2 is 28 mm each, center part (elastic body)
The width of 1 is 30 mm, and the width of the boundary areas 3 and 3, which are formed by mixing and integrating the two forming materials, is 2 mm each. Therefore, the width of the boundary area and the thickness of the tape base material are 2 mm. The ratio was 4.

An adhesive layer 4 coated with a rubber adhesive is provided on one side of both ends 2, 2 of this tape base material 10, and a back treatment layer (not shown) coated with silicone is provided on the other side as shown in FIG. An elastic fastening tape 11 of the present invention shown in Fig. 1 was obtained. Although not shown, the extrusion molding machine 22 has two nozzles for respectively extruding the inelastic body forming material to form both end portions 2, 2.

The fastening tape 11 obtained as described above has a width of 25 mm.
Cut into mm pieces and size 90mm x 25mm x 0.5mm (second
Even when the size of the 10' part in the figure) was used, no curling was observed, and when the parts up to 10 mm from both ends were sandwiched between chucks and pulled at 1500 gf, the center part 1 changed from 30 mm to 90 mm. Boundary area 3,3
were extended from 2 mm to 2.1 mm, respectively, but both ends 2,
The remaining 18mm part between the chucks in 2 is
It did not grow at all and remained at 18mm. In addition, no abnormal wavy deformation was observed in the boundary areas 3, 3 and both ends 2, 2, and when the tensile force was reduced to 0 after 3 minutes, the length of the central portion 1 was 35 mm immediately after, and 35 mm after 5 minutes. was 33mm.

When the above tape 11 was used to fasten a disposable diaper, it was found that it easily adhered to the flexible diaper surface material, easily expanded and contracted even when the wearer exercised, and the central part (elastic body) always had a length of 40 to 70 mm. As shown in FIG. 4, there was no fear that the ends (inelastic body) and boundary area would curl and peel off from the disposable diaper, and the tape-attached portion did not deform at all even after 5 hours.

〔Effect of the invention〕

The elastic fastening tape of the present invention is superior to conventional fastening tapes of this type in various respects.

That is, the elastic fastening tape of the present invention is
In particular, because the boundary area is formed by mixing and integrating the elastic body-forming material and the inelastic body-forming material, the physical properties of the boundary zone area between the elastic body and the inelastic body, which have different physical properties, are discontinuous. As a result of the stress applied to the boundary area being dispersed without sudden change, when used for an adherend such as a disposable diaper, the elastic body expands and contracts smoothly, and the inelastic material is released from the adherend. Body (both ends)
There is no risk of peeling or breakage in the boundary area due to curling or wavy deformation.

In addition, tape base materials made by changing the thickness of the sheet at both ends, the center, and their boundary areas may have poor winding properties when forming the tape base material, even if they have apparent tape physical properties. It is difficult to put it to practical use because it has poor secondary processing properties such as adhesive coating, back processing, and cutting.
The stretchable fastening tape of the present invention has a constant thickness of the tape base material and is configured to connect both ends and the boundary area, so that stress does not concentrate between the elastic body and the inelastic body. Due to its structured structure, it has excellent moldability and secondary processability.

Furthermore, since the tape base material of the stretchable adhesive tape of the present invention is molded from a thermoplastic polymer, it is easier to manufacture and has higher productivity than molded from a thermosetting polymer.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view showing one embodiment of the elastic fastening tape of the present invention, FIG. 2 is a perspective view showing an example of the tape base material of the stretchable fastening tape of the present invention, and FIG. FIG. 4 is a schematic diagram showing an example of manufacturing a tape base material of a stretchable fastening tape of the present invention, and FIG. 4 is an enlarged sectional view showing a curled state that occurs when a conventional fastening tape is fastened. DESCRIPTION OF SYMBOLS 1... Center part (elastic body), 2... End part (inelastic body), 3... Boundary area part, 4... Adhesive layer, 10...
... Tape base material, 11 ... Stretchable fastening tape.

Claims (1)

[Claims] 1. A central portion made of an elastic body, and 2. A central portion made of an inelastic body.
an adhesive layer is provided on one surface of at least the same side of the two inelastic bodies of the tape base material, which is formed by integrally bonding the two end portions through the boundary area, and 1. A fastening tape having elasticity, characterized in that the region is formed by blending and integrating the elastic body-forming material and the inelastic body-forming material. 2. The stretchable adhesive tape according to item 1, wherein the boundary region is formed by melting and extruding both or either of an elastic body-forming material and an inelastic body-forming material. 3 The ratio (A/B) of the width of the boundary area (width between the elastic body edge and the inelastic body edge connected via the boundary area) A and the thickness B of the tape base material is 0.2 to 20. The elastic fastening tape according to claim 1, characterized in that the elasticity is 20. 4. The stretchable adhesive tape according to claim 1 or 3, wherein the tape base material has a thickness of 0.02 to 3 mm. 5. The stretchable fastening tape according to claim 1, wherein the elastic modulus of the inelastic body is 1.5 times or more that of the elastic body.