JP2834628B2 - Adhesive tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape having good hand-cutting properties in the weft direction using a flat yarn woven fabric used as a packaging material as a base material.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive tape adheres with a light pressure such as a fingertip without the aid of a solvent or heat, and basically comprises a base material and a pressure-sensitive adhesive. The pressure-sensitive adhesive is selected from acrylic, rubber, silicone, etc. depending on its use and function.
Also, for the base material, in addition to the conventional kraft paper and nonwoven fabric, an easy-to-use adhesive tape that can be easily cut linearly by hand without using scissors or a cutter in the lateral direction of the tape is obtained. For this reason, some of them have been treated as woven cloth. This kind of conventional
In order to ensure sufficient tensile strength in the warp direction, the warp yarn has a tear strength that can be easily cut by hand without using scissors or cutters in the weft direction of the tape. With a flat yarn, the warp has a low denier of about 1/2 to 1/3 of the weft and the warp is about 2% lower than the weft driving density.
A pressure-sensitive adhesive tape has been invented in which laminating is applied to the front and back of a base fabric woven at a high density of up to three times and a pressure-sensitive adhesive is attached (Japanese Patent Publication No. 41189/1989). In the specific example of this publication, the warp is woven in the state of a woven fabric with a fineness of 75 to 150 denier (practical limit 50
~ 250 deniers, 30-60 yarns / inch, weft fineness 200-400 deniers, 12-25 yarns / inch, and in the example, 115 warp yarns, 46 yarns. The physical properties after pressure-sensitive adhesive application after laminating on both sides and 16-inch / inch-punched woven fabric of 320 denier weft yarn indicate hand-cutting property. The longitudinal tensile strength indicating the tensile strength is 38.4 kgf / 5 cm.

[0003]

By the way, the adhesive tape formed by the above method can be used from the viewpoint of physical properties, but it is not a product which is easy to use in terms of hand cutting properties.
In addition, a flat yarn that directly affects the physical properties of the adhesive tape
Since the physical properties of the resin do not substantially depend on the fineness, reproducibility is extremely difficult. For example, the tear strength in the weft direction as an adhesive tape is determined by the physical properties of the warp, which is selected based on the correlation between the strength and the elongation, and largely depends on the production conditions of the warp. That is, even if the yarn has the same fineness, the range of the high elongation is extremely wide, and if a warp having a high elongation is used in the above method, even if the yarn is fixed by laminating, the fracture surface of the adhesive tape due to tearing is fuzzy. Is a problem.

[0004]

DISCLOSURE OF THE INVENTION The present invention is based on the results of intensive studies on the physical properties suitable for an adhesive tape from the physical properties of the weft constituting the woven fabric used as the base material. Is made of a flat yarn having a fineness of 60 to 80 denier, a tensile strength of 300 to 500 gf and an elongation at break of 20% or less, obtained by slitting and stretching a thermoplastic synthetic resin film. On one side of a relatively densely woven fabric with about 3 times higher fineness,
Of the first laminate on the other side
Cover the second laminate layer with about twice the thickness of the layer,
The total thickness of the first laminate layer and the second laminate layer is 60
A laminate having a tensile strength in the warp direction of 3 to 80 μm.
0 kgf / 5 cm or more and tear strength in the weft direction of 300
gf or less as a tape base material, at least
This is an adhesive tape having a pressure-sensitive adhesive layer provided on one side .

[0005] The flat yarn used for the warp yarn is formed by melting and extruding a thermoplastic synthetic resin such as polypropylene or polyethylene resin from a T-type die or a circular die, cooling the film, slitting it into a narrow width, and forming a hot plate or a heat roll. The warp yarn has a fineness of 60 to 80 denier, a tensile strength of 300 to 500 gf and an elongation at break of 20%.
Must be:

Here, each numerical value will be described. The reason why the flat yarn fineness of the warp yarn is set to 60 to 80 denier is that the tape thickness is inevitably almost constant (20) in order to make the molecular orientation uniform from the normal production method of the flat yarn.
.About.30 .mu.), Which represents the tape width. From the state of the fracture surface when the adhesive tape is torn, the fineness of the fineness having a tape width of about 0.3 to 0.5 mm is preferable. In this range, a flat yarn having a preferable high elongation as a warp can be stably and efficiently obtained, and the efficiency of weaving is also in a range of fineness.

[0007] The tensile strength of the warp flat yarn is 300.
The reason why it is in the range of -500 gf is that if it is out of the small range, the weaving efficiency is extremely deteriorated, and if it is out of the large range, the hand-cutting property when the adhesive tape is finished is deteriorated. Here, it is considered that a warp (500 gf or more) having a relatively large tensile strength is woven by reducing the number of yarns to be woven and the physical properties are adjusted to preferable physical properties in a state of a tape base material which is laminated on both sides with a woven base fabric. However, the ease with which the tape base material can be torn in the weft direction depends largely on the tensile strength per warp yarn. If the warp yarn has a large tensile strength, it is naturally difficult to tear, and the weaving efficiency is reduced. The smoothness of the cloth surface is inferior, and the appearance as an adhesive tape cannot be said to be good.

The elongation at break of the flat yarn of the warp is 20
The elongation at break is set so that even if the adhesive tape is successfully torn in the weft direction, the cut end of the warp does not remain in the cut and does not fluff, and the draw ratio is not more than 100%. And heat setting. However, depending on the physical properties of the thermoplastic synthetic resin used, the elongation at break may be large under the setting of the production conditions, and the elongation at break is set to 20% or less while maintaining the same fineness and tensile strength. Can be set by adding an inorganic filler such as calcium carbonate to a thermoplastic synthetic resin, and the addition amount is preferably 0.2 to 5% for maintaining conditions.

The weft preferably has a high fineness of about three times that of the warp in view of the efficiency of weaving and the appearance of the adhesive tape. Further, the base material is corrugated during heat treatment such as laminating. Those having a heat shrinkage equivalent to that of the warp are preferable so as not to generate any heat.

In weaving these warps and wefts,
The driving density of the warp may be appropriately selected so as to have a tensile strength that can withstand use when used as a tape base material, but the tensile strength of the warp and the deterioration of weaving during weaving and thermal deterioration during lamination It is preferable to drive the weft densely from the viewpoint of the smoothness of the surface of the base cloth and the appearance of the adhesive tape. The rate is about 10%, that is, the tape width of the weft is 1.2 mm
If it is made to be about, the implantation density becomes about 18 pieces / inch.

A tape base is obtained by extrusion laminating thermoplastic synthetic resin of the same type as the warp yarn on both sides of the base fabric woven in this manner. When laminating a woven fabric, the thickness of the laminating layer should be 30 to smooth the surface of the tape substrate.
４０40 μm, that is, the total thickness of the laminate layers on both sides is 6
When setting the temperature to 0 to 80μ, set the temperature higher than the normal melt extrusion temperature or reduce the processing speed of the laminate to cause thermal degradation to the woven fabric and reduce the tear strength of the tape base in the weft direction. Let it. However, raising the melt extrusion temperature oxidizes the laminate resin, and lowering the processing speed causes a problem because the production amount decreases.

In view of these problems, the present invention provides a
Form a relatively thin first laminate layer on the
On the other side, the second laminate layer, the first laminate layer
Coat with a thickness of about twice the thickness . Here, the deterioration due to heat is a synergistic effect of the contact temperature and time. At the same laminating speed, the larger the amount of resin, the longer the contact time of the resin in a slightly high temperature state, and the thermal deterioration is caused by the woven fabric. Although it is the total amount of the resin coated because the many coating the resin amount on both sides material cost is increased in order to in the same amount, the slave
While equal to the total thickness of the previous two laminate layers,
The first laminate layer is made to be a thin layer to make the surface smooth, and to substantially give sufficient thermal deterioration when forming the second laminate layer. In addition, even if the melt extrusion temperature is set higher than normal and the woven fabric is thermally degraded, the inferior effect at high temperature is compensated by the time effect, so that laminating at normal temperature can sufficiently cope with it. It is.

Further, since the warp yarn of the woven fabric is firmly fixed by forming the laminate layer, the adhesive tape base material has no escape of the warp yarn when it is torn in the weft direction as an adhesive tape. A pressure-sensitive adhesive is applied to a material having a tensile strength in the warp direction of 30 kgf / 5 cm or more and a tear strength in the weft direction of 300 gf or less to form the pressure-sensitive adhesive tape of the present invention. The surface to be coated is preferably, but not limited to, the surface of the second laminating layer, since the smoother the surface of the substrate is, the thinner the layer, the more the pressure-sensitive adhesive can be applied uniformly.

[0014]

According to the present invention, the effective physical properties required for the adhesive tape are determined from the physical properties of the warp yarns constituting the woven fabric used as the base material.
Furthermore, the adhesive tape to be manufactured is strong and easy to cut.
It can be made very suitable as compared with the conventional product.

[0015]

[Embodiment] Hereinafter, an embodiment will be described.

[0016] Polypropylene (MI =
(1.7, melting point: 156 ° C), extruded at 240 ° C by inflation, cooled, slit, stretched at 150 ° C, annealing at 155 ° C by hot plate contact stretching. A flat yarn was manufactured by changing the magnification.

Next, weaving is performed by using each flat yarn as a warp to obtain a base fabric. As the weft, a yarn having a fineness of 300 denier manufactured in the same manner as the above-mentioned flat yarn is used. The driving density of the warp yarn was 46 yarns / inch and the weft yarn was 18 yarns / inch.

Next, a laminate layer is formed on both sides of the base fabric. Polypropylene (MI = 22.0, melting point 1)
41 ° C.), and a first laminating layer having a thickness of 20 μm was formed on one surface of the base fabric at a melt extrusion temperature of 280 ° C. as a first step. As the second step, the other side of the base fabric is melt-extruded at 280 ° C
Forming a second laminating layer having a thickness of 40 .mu.m, subjecting the surface of the second laminating layer to a corona discharge treatment to form a pressure-sensitive adhesive layer, and producing an adhesive tape. Table 1 shows the test results. In the following physical property evaluation, tensile elongation was
JIS-L1096, tear strength is measured according to JIS-P8116.

[0019]

[Table 1]

From Table 1, it can be seen that the warp flat yarns have substantially the same fineness, but the physical properties vary greatly depending on the draw ratio. Since the warp flat yarn of Comparative Example 1 had no tensile strength, the productivity of the flat yarn itself was poor, and the weaving efficiency for the warp was poor, so that it was practically impossible to use. The adhesive tape produced in Comparative Example 2 has a low tear strength and can be easily torn by hand. However, since a warp having an elongation at break of 25.3% is used, the warp is fixed by forming a laminating layer. However, since each warp breaks at the time of tearing of the base material, the cut ends of the warp remain in a sawtooth shape at the cut edge of the tear in the weft direction, causing fluffing, making it a desirable product in appearance. Did not. The pressure-sensitive adhesive tape of Comparative Example 3 has good weaving efficiency because the tensile strength of the warp flat yarn is large and the elongation at break is small.
The cut end of the tape is not fuzzy, but is not suitable because it requires force for tearing as compared with the embodiment. Here, in Examples 1, 2, and 3, the physical properties of the warp flat yarn and the physical properties of the raw material of the adhesive tape belong to the present invention, and are suitable products. The warp flat yarn is made of 0.8% calcium carbonate in the raw polypropylene.
%, Which is produced at the same draw ratio as Comparative Example 2 and has the same tensile strength, but has a small elongation at break and is suitable for use as a warp yarn. I was able to do it.

Next, a tape by a method of forming a laminate layer is described.
Verify the effect on the physical properties of the base material. A polypropylene (MI = 22.0, melting point: 141 ° C.) is coated as a first laminating layer on a base fabric woven using the flat yarn used in Example 2 on a warp yarn at a melt extrusion temperature of 280 ° C. and a thickness of 30 μm. Then, a second laminate layer having a thickness of 30 μm formed on the other surface is referred to as Comparative Example 4, and a first laminate having the first and second laminate layers formed at a melt extrusion temperature of 310 ° C. is a comparative example. Table 2 shows the results of the respective strength tests as No. 5.

[0022]

[Table 2]

In Table 2, Comparative Example 4 was the same as the Example with a total thickness of the laminate layer of 60 μm, but the preferable decrease in physical properties due to thermal degradation did not appear as much as in the Example. Comparative Example 5 is a conventional laminating process in which the melt extrusion temperature is increased, and the same thermal deterioration effect as in the example can be confirmed. However, the resin is easily oxidized, which is not a preferable state in the production process. .

[0024]

According to the present invention, in order to obtain a suitable adhesive tape, the physical properties of the warp yarns constituting the woven fabric used as the substrate have been examined, and the reproducibility thereof is extremely easy. It became. Here, since the warp yarn can be a flat yarn which can be produced without setting special conditions or improving production facilities, the productivity of the flat yarn itself is good, and the physical properties of the warp yarn are suitable for the weaving efficiency. Was something. Further, the laminating layers formed on both sides of the base fabric cover the second laminating layer about twice as thick as the first laminating layer of the thin film. Since the same suitable thermal degradation to the substrate as the laminate by increasing the melt extrusion temperature can be exhibited at the ordinary melt extrusion temperature, no extra power cost is required and the oxidation of the resin is suppressed. The adhesive tape manufactured according to the present invention has both the necessary strength in the warp direction and the required cutting property in the weft direction, and the cutting property is much easier than that of the conventional product. The adhesive tape is useful because it can be cut, and the condition of the cut surface of the adhesive tape is a good high-quality adhesive tape that does not fluff at the cut end of the warp.
It was possible to make it.

[Brief description of the drawings]

FIG. 1 is a partially enlarged plan view of a woven fabric used as a base material of an adhesive tape of the present invention.

FIG. 2 is a sectional view of the adhesive tape of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Warp 2 Weft 3 Woven cloth 4 First laminating layer 5 Second laminating layer 6 Pressure sensitive adhesive layer

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ identification code FI D04D 9/00 D04D 9/00 D06M 15/00 D06M 15/00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09J 7/00-7/07 B32B 27/12 D02G 3/06 D03D 1/00 D03D 15/00 D04D 9/00 D06M 15/00

Claims (1)

(57) [Claims] 1. A warp having a fineness of 60 to 80 denier, a tensile strength of 300 to 500 gf and an elongation at break of 20 obtained by slitting and stretching a thermoplastic synthetic resin film.
% Of flat yarn, one side of a relatively densely woven base fabric with a weft of about 3 times the fineness of the warp
To the first laminate layer, and the other side
Cover the second laminate layer with about twice the thickness of the minate layer.
Cover, the total thickness of the first laminate layer and the second laminate layer
A laminate having a thickness of 60 to 80 μm and tensile in the warp direction
Strength is 30kgf / 5cm or more and tear strength in the weft direction
A pressure-sensitive adhesive tape comprising a laminate having a thickness of 300 gf or less as a tape substrate and a pressure-sensitive adhesive layer provided on at least one surface.