JPH04292164A - Bonding structure of adhesive tape and manufacture of diaper - Google Patents

Abstract

PURPOSE:To enhance adhesive strength and to smoothly perform manufacturing process by heat bonding with a body to be bonded after performing a mold release processing. CONSTITUTION:As for this adhesive tape 1, a mold release processing is performed to one face or both faces, a mold release effect of the mold release processing face 3 is migrated to an adhesion effect by heat treatment, and even in the case of a one-face tape, it can be used as a separatorless double face tape. Also, since thickness of a mold release agent can be controlled more easily than a conventional pressure sensitive adhesive, generation of trouble in the mold release processing process can be prevented. Moreover, in the case the adhesive tape 1 is used as a diaper sticking tape, adhesive strength of the adhesive tape 1 to a diaper 5, especially, shear adhesive strength is improved remarkably, and also, the manufacturing process can be performed smoothly, and as a result, the diaper can be manufactured efficiently.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding structure for adhesive tapes that lose their release effect due to heat and a method for manufacturing diapers. The adhesive tape is used for applications in which a release-treated surface and an adherend are to be bonded, and specifically, it is not limited to tape systems for attaching disposable diapers, but is also used for stationery, sanitary materials, medical supplies, etc. It can also be effectively used for materials.

0002

BACKGROUND OF THE INVENTION Conventionally, various adhesive tapes have been used as means for securing disposable diapers, but if the adhesive strength of the adhesive tape is weak, it is impossible to securely secure the disposable diapers.
The tape may separate from the diaper, making it unsuitable for practical use.

[0003] Therefore, as a first conventional example, the
A tape-type fixing structure disclosed in Japanese Patent No. 34978 is known. In this conventional example, the front and back parts of the Y-shaped tape are
The tape is attached individually to the front and back surfaces of the side edges of the diaper, and the fixing portion of the tape is used as a means for attaching the diaper.

However, in this conventional example, the fixing part of the tape is bent and overlapped with the surface part of the tape, so bending takes time and the manufacturing process becomes complicated. Moreover, since the tapes are overlapped, the thickness of the fastening portion of the diaper increases, and as a result, the fastening portion becomes hard and may damage the infant's skin.

On the other hand, as a second conventional example,
A sanitary article disclosed in Japanese Patent No. 95105 is known. In this conventional example, one end of the tape (fastening piece) is sandwiched between the top sheet and back sheet of the diaper to adhere them to each other, and the tensile force applied to the tape is distributed between the top sheet and back sheet. In addition to preventing the tape from coming off, since the tape does not have a double structure unlike the first conventional example, the thickness of the portion where the diaper is attached can be reduced. As a result, there is an advantage that the fastening portion can be prevented from becoming hard.

[0006]

However, in the second conventional example, an adhesive is applied to both the top sheet and the back sheet of the diaper, and then a tape is adhered to the applied area. Therefore, a step of applying adhesive to two locations on the diaper is required.

[0007] When applying the adhesive to the sheet surface, if the thickness of the adhesive is not set uniformly, the adhesive force with the tape will weaken, causing the problem that the tape will come off during use of the diaper. However, adhesives are generally susceptible to conditions such as temperature and dryness, and it is difficult to control their thickness. Therefore, it takes time and effort to adjust the thickness of the adhesive, and the process of applying the adhesive cannot proceed smoothly.

Moreover, if the adhesive application process is directly connected to the diaper production line, any trouble that occurs in the application process will have an undesirable effect on the next manufacturing process, resulting in production delays. This has the disadvantage of causing a decrease in efficiency.

[0009] This invention was made to solve the above-mentioned problems of the prior art, and it is made to thermally bond to the adherend after the mold release treatment, thereby increasing the adhesive strength and reducing the manufacturing process. The purpose of the present invention is to provide an adhesive tape bonding structure and a diaper manufacturing method that can facilitate the process.

0010

[Means for Solving the Problem] After extensive research, the inventor applied a release treatment to one or both sides of the tape, and applied heat to the release treatment surface to an adherend such as a synthetic resin film or nonwoven fabric. By focusing on the fact that when bonded, the release effect is lost and the effect shifts to an adhesive effect, even a single-sided tape coated with a conventional adhesive on only one side can be used as a separator-less double-sided tape. Furthermore, it has been found that even a tape that has been subjected to release treatment on both sides can be used as a double-sided tape. In addition, when performing mold release treatment using a long-chain alkyl mold release agent, the mold release agent is generally less affected by conditions such as temperature and dryness than adhesives, and its thickness can be controlled. It was found that it was easy to do this, and as a result, it was possible to prevent troubles as much as possible during the adhesive tape release process.

[0011] Through further research, the inventor found that when the adhesive tape was used as a diaper fastening tape, the adhesive strength between the diaper fastening part and the adhesive tape, especially the shear adhesive strength, was significantly improved. understood. Moreover, as mentioned above, it is possible to prevent troubles from occurring during the release process of adhesive tapes, so we discovered that even when the adhesive tape manufacturing process is directly connected to the diaper manufacturing line, manufacturing can be made smoother. This led to the completion of the invention.

That is, the present invention provides a bonding structure for an adhesive tape in which one or both sides of the tape are subjected to a release treatment, and the release treated surface loses its release effect due to heat and is bonded to an adherend. This is related.

[0013] Furthermore, it is preferable that a mold release treatment is performed using a long-chain alkyl type mold release agent.

[0014]Furthermore, a step of manufacturing an adhesive tape by subjecting one or both sides of the tape to a release treatment, a step of overlapping the release-treated side of the adhesive tape on the side edge of the diaper, and a step of overlapping the release-treated side of the adhesive tape with the side edge of the diaper; The present invention relates to a method of manufacturing a diaper, which includes a step of thermally bonding the adhesive tape to the side edge of the diaper by applying heat and pressure from above.

[0015]

[Operation] The base material of the adhesive tape applied to this invention is selected arbitrarily depending on the intended use of the adhesive tape. As shown in FIG. 1, the adhesive tape has, for example, a release-treated surface 3 formed on one side of a base material 2, and a conventional adhesive 4 coated on the other side. Further, the left half of the adhesive tape 1 is sandwiched between a top sheet 6 and a back sheet 7 at the side end portion of the diaper 5, and the release-treated surface 3 is bonded to the top sheet 6 side by thermal adhesion.

[0016] The release agent applied to the adhesive tape 1 is selected from a material such as a long-chain alkyl release agent, which has the characteristic of losing its release effect and shifting to an adhesive effect when subjected to high-temperature pressurization. Ru. This mold release agent is pattern-coated over a portion or the entire surface of one or both sides of the tape, and in the next step is thermally bonded to the side edges 5a, 5b of the diaper as shown in FIG.

The adhesive tape 1 and the diaper 5 may be thermally bonded by any conventional thermal bonding method, such as an ultrasonic welder, a heat press, a rubber-based or olefin-based hot melt adhesive, etc. Examples include a method using a molten thermoplastic, and a method of thermally adhering to a molten thermoplastic.

When the adhesive tape 1 is thermally bonded to the diaper 5 by the above method, the shear adhesive force between the adhesive tape 1 and the diaper 5 is preferably about 1.0 kg/25 mm or more. In other words, when the adhesive tape 1 is used as a diaper fastening tape system, the shear adhesive force when the infant is stationary is approximately 200 g/25 mm, and considering the force applied when the infant moves, it is approximately 1.0 kg/25
mm or more and approximately 4.0 kg/25mm,
This is desirable from a safety and practical standpoint.

Next, the present invention will be explained in more detail with reference to Examples.

<Example 1> A hot-melt adhesive is dissolved in a solvent, applied to a release paper so that the thickness after drying is 50 μm, and dried at 120° C. for 3 minutes. After drying, this was cut into 1 mm wide pieces, bonded to a polyethylene film 32, the release paper was peeled off, the adhesive 33 was transferred, and this film 32 was cut into pieces with a width L of 25 mm as shown in FIG.
Cut it so that it looks like this.

Then, a fastener tape 31 is attached to a 1 mm thick iron plate 30, and a hot melt adhesive 3 of a polyethylene film 32 cut to a width of 25 mm is attached to the back side of the fastener tape 31.
Attach the sides marked 3.

[0022] Thereafter, a crimped sample is prepared using a heat seal tester. After being left for 2 hours at 23° C. and 60% RH, the shear adhesive strength was measured using a tensile tester. At this time, the crimping force was 3 kg/pressure, the crimping time was 3 seconds, and the area was 25 mm2.
shall be. Attach this to a diaper and set it at 300 mm/mi.
A tensile test was conducted at a tension of n. As a result, Table 1
Long chain alkyl treatment of and the experimental data shown in solid line 11 in FIG. 4 were obtained.

<Example 2> Under the same conditions as in Example 1 above,
When a fastener tape was attached to a commercially available diaper and three pieces of hot melt adhesive were placed at intervals of 5 mm, the experimental data shown by the solid line 11 in Tables 1 and 2 and FIG. 4 was obtained. As a result, it can be seen that the fastener tape subjected to the mold release treatment has a shear adhesive strength equal to or greater than that of the fastener tape not subjected to the mold release treatment.

[0024]

[Table 1]

[0025]

[Table 2]

<Comparative Example 1> A diaper was thermally bonded to a zipper tape that had not been subjected to release treatment using a rubber-based hot melt adhesive. The experimental data shown in Tables 1 and 2 and the dot-dashed line 12 in FIG.
g/25mm) is lower than that of a zipper tape subjected to release treatment at temperatures above 110°C. 1
This is because when the temperature exceeds 10° C., the mold release effect of the long-chain alkyl type mold release agent is lost and the mold release effect shifts to an adhesive effect.

<Comparative Example 2> A zipper tape treated with a silicone mold release agent and a diaper were thermally bonded using a rubber-based hot melt adhesive. According to the experimental data indicated by the two-dot chain line 13 in Tables 1 and 2 and Figure 4, the shear adhesive strength (kg/25 mm) of the silicone-treated zipper tape is different from that of the release-treated zipper tape and the untreated zipper tape. In comparison, it can be seen that the shear adhesive strength is significantly inferior.

[0028] As a result of the above, when one or both sides of the tape is subjected to a release treatment and the release treated side is thermally bonded to a diaper, the release effect is lost and the effect shifts to an adhesive effect, so separator-less It could be used as double-sided tape.

[0029] Furthermore, when performing mold release treatment using a long-chain alkyl mold release agent, the mold release agent is generally less affected by conditions such as temperature and dryness, and has a higher performance than conventional adhesives. It was found that it was easy to control the thickness, and as a result, troubles in the adhesive tape release process could be prevented as much as possible.

Furthermore, when the adhesive tape was used as a diaper fastening tape, it was confirmed that the adhesive strength of the adhesive tape to the diaper, especially the shear adhesive strength, was significantly improved. Furthermore, since troubles can be prevented as much as possible during the adhesive tape release process, even if the adhesive tape manufacturing process is directly connected to the diaper manufacturing line, it is possible to streamline the manufacturing process and improve diaper production. It has become possible to manufacture efficiently.

As a second embodiment of the present invention, as shown in FIG. 5, the release-treated surface 3 of the adhesive tape 1 may be thermally bonded to the back sheet 22 side of the diaper 20 instead of the top sheet 21 side. .

As a third embodiment, as shown in FIG. 6, instead of a diaper, the release-treated surface 3 of the adhesive tape 1 is thermally bonded to one surface of an adherend 23 made of a synthetic resin film or nonwoven fabric. It's okay.

Furthermore, as a fourth embodiment, as shown in FIG. 7, a mold release treated surface 3 is formed on one side of the base material 2, and a mold release treated surface 3' and an adhesive 4' are formed on the other side. and the mold release treated surface 3,
3' may be thermally bonded to both sheets 6 and 7 of the diaper, respectively.

[0034]

Effects of the Invention As explained above, according to the present invention, by applying heat treatment after the mold release treatment, the mold release effect of the mold release treated surface is transferred to the adhesive effect, and even though it is a single-sided tape, It is useful as a separatorless double-sided tape. Furthermore, since the thickness of the release agent can be controlled more easily than with conventional adhesives, troubles can be prevented from occurring in the process of releasing the adhesive tape. Furthermore, when the adhesive tape is used as a diaper fastening tape, the adhesive strength between the diaper fastening part and the adhesive tape is greatly improved,
As a result of being able to facilitate manufacturing, diapers can be manufactured efficiently.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an adhesive tape according to a first embodiment of the present invention.

FIG. 2 is a front view of a diaper using the same adhesive tape.

FIG. 3 is a schematic diagram showing an example of measuring the adhesive strength of the adhesive tape.

FIG. 4 is a graph showing the shear adhesive strength between the same adhesive tape and a diaper.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a sectional view showing a fourth embodiment of the present invention.

[Explanation of symbols]

1 Adhesive tape 3 Mold release treated surface 4 Adhesive surface 5 Diaper 6 Top sheet 7 Back sheet

Claims (3)

[Claims] 1. An adhesive tape bonding structure characterized in that one or both surfaces of the tape are subjected to a release treatment, and the release treated surface loses its release effect due to heat and is bonded to an adherend. 2. The adhesive tape bonding structure according to claim 1, wherein the adhesive tape is subjected to a mold release treatment using a long-chain alkyl mold release agent. 3. A step of manufacturing an adhesive tape by subjecting one or both sides of the tape to a release treatment, a step of overlapping the release-treated side of the adhesive tape on a side edge of a diaper, and the release-treated side A method for manufacturing a diaper, comprising the step of thermally bonding the adhesive tape to the side edge of the diaper by applying heat and pressure from above.