JPH09137133A - Adhesive tape - Google Patents

Abstract

(57) Abstract: An adhesive tape in which an adhesive is applied to the concave surface side of a polyolefin resin substrate film having one smooth surface and the other concave surface, and the adhesive tape is applied in the width direction. It is an object of the present invention to provide an improved pressure-sensitive adhesive tape having a reduced elongation in the longitudinal direction without deteriorating the characteristics such as hand-cutting property. SOLUTION: One surface is a smooth surface, and the other surface has a depth of 0.03 to 0.3 mm orthogonal to the longitudinal direction of the adhesive tape and an interval of 0.5 to 5 mm.
The base film made of an unstretched polyolefin resin formed on the surface having a concave portion which is a score parallel line of mm and a composite layer composed of a non-woven fabric or a split cloth reinforcing material and an adhesive on the surface having the concave portion. It was an adhesive tape.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive tape. More specifically, the present invention is directed to a concave surface side of a polyolefin resin base film formed by forming a smooth surface on one surface and a surface having a specific concave portion on the other surface (hereinafter, the surface having the concave portion is referred to as “concave surface”). In the adhesive tape formed by applying the agent, without impairing the hand tearability of the adhesive tape in the width direction,
The present invention relates to a pressure-sensitive adhesive tape in which the lengthwise elongation of the pressure-sensitive adhesive tape is reduced.

[0002]

2. Description of the Related Art Generally, an adhesive tape is commercially available in the form of a roll of a base film 101 coated with an adhesive 102 as shown in FIG. After pulling out (developing) to (1), it is cut at a desired position and used. A pressure-sensitive adhesive tape obtained by applying a pressure-sensitive adhesive to the concave surface side of a polyolefin resin substrate film having one smooth surface and the other concave surface is disclosed in JP-A-3-478.
It is described in No. 85. This adhesive tape is obtained by applying the adhesive 102 on the concave surface 103 of the base film 101 of FIG. 6, and the longitudinal section of the adhesive tape is as shown in FIG. 105 is a recess.

[0003]

One of the characteristics of this adhesive tape is that it is excellent in hand-cutability, that is, it does not require the use of a cutting tool such as a saw-toothed cutter like commercially available Sellotape (registered trademark). However, the point is that the adhesive tape can be cut straight in the width direction only by the hand (fingertip). However, when an external force is applied in the longitudinal direction of the adhesive tape, for example, when the adhesive tape wound in a roll shape as shown in FIG. There has been a demand for improvement in terms of reducing elongation.

Here, the property that the pressure-sensitive adhesive tape easily extends in the longitudinal direction is the property that the pressure-sensitive adhesive tape easily shrinks after the pressure-sensitive adhesive tape is attached to the adherend, and therefore, for example, the surface to be coated and the surface not to be coated. In applications where an adhesive tape is used to distinguish between (for masking in painting), there may be a problem that the boundary of the coating film is not clear.

An object of the present invention is to provide a pressure-sensitive adhesive tape obtained by applying a pressure-sensitive adhesive to the concave surface side of a polyolefin resin base film having one surface that is smooth and the other surface that is concave.
An object of the present invention is to provide an improved pressure-sensitive adhesive tape in which elongation in the longitudinal direction is reduced without impairing characteristics such as hand tearability in the width direction of the pressure-sensitive adhesive tape to a problematic degree.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have found an adhesive tape obtained by applying an adhesive to the concave side of a polyolefin resin base film having one smooth surface and the other concave surface. A keen research on the development of an improved adhesive tape in which the adhesive tape is difficult to stretch in the direction when an external force is applied in the longitudinal direction of the adhesive tape without impairing the characteristics of the adhesive tape in the width direction such as hand tearability. It's piled up.
As a result, it was found that on the concave surface of the base material film to which the adhesive is applied, an adhesive tape formed by forming a composite layer consisting of a non-woven fabric or a split cloth and an adhesive fulfills the above purpose,
The present invention has been completed.

That is, according to the present invention, one surface is a smooth surface and the other surface has a depth of 0.03 to 0.3 perpendicular to the longitudinal direction of the adhesive tape.
from a non-stretched polyolefin resin substrate film formed on a surface having concave portions which are notched parallel lines and have an interval of 0.5 to 5 mm, and a non-woven fabric or a split cloth reinforcing material and an adhesive on the surface having the concave portions. And a composite layer consisting of

Hereinafter, the present invention will be described in detail.
When the present invention is described with reference to the drawings, what is shown is merely an example of the present invention, and the present invention is not limited to what is shown. Further, the drawings are focused on drawing the present invention in an easy-to-understand manner, and the scale is not necessarily an exact reflection of the actual situation.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A longitudinal section of an adhesive tape of the present invention is illustrated in FIG. The bottom layer in the figure is an unstretched polyolefin resin substrate film 1, one side of which is a smooth surface 4 (the lower side of the figure, the surface of which is not visible in the figure) and the other side is the length of the adhesive tape. The depth (D) perpendicular to the direction is 0.03 to 0.3 mm, and the interval (W) is 0.5 to 5 mm. ) And the depth of the recess 5 (D)
(TD) is generally 10 to 100 μm. On the concave surface 3 of the base film 1, there is a composite layer 6 composed of a non-woven fabric or a split cloth as a reinforcing material and the adhesive 2.

Here, the "composite layer" is a layer in which a non-woven fabric or a split cloth as a reinforcing material is mixed with an adhesive, and the layer of the reinforcing material and the layer of the adhesive are separate layers. Existing as a layer, that is, a layer of the pressure-sensitive adhesive on the layer of the reinforcing material, or a layer of the reinforcing material on the layer of the adhesive does not mean the layer. This is because the non-woven fabric or the split cloth is a cloth having a gap, and therefore the adhesive exists also between the gaps, and the reinforcing material layer and the adhesive layer cannot exist as separate layers.

The unstretched polyolefin resin base film 1 according to the present invention can be manufactured from a known polyolefin resin. Examples of the polyolefin resin include polyethylene resin, polypropylene resin, copolymer resin of ethylene and propylene, copolymer resin of ethylene and / or propylene and one or more other α-olefins. , Butene as α-olefin
1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, 4-methylpentene-1, decene-1 and the like. The preferred polyolefin resin is a polyethylene resin. The molecular weight of the polyolefin resin is not particularly limited as long as it can be formed into a film, but when expressed by a melt index which is a scale showing the flowability of the resin, it is generally in the range of 0.2 to 20 g / 10 minutes,
Preferably 1-10g / 10min (load 2.16kg, temperature 190 ℃)
Range.

Regarding the shape of the concave surface 3 which is the other surface of the base film 1, the depth (D) of the recess 5 is 0.03 to 0.3 mm, preferably 0.04 to 0.12 mm, and the thickness of the base film 1 (T )
The difference (T-D) between the depth and the depth (D) of the recess 5 is generally 10 to 1
00 μm. When the depth (D) of the recess 5 is less than 0.03 mm, the adhesive tape has a large tensile strength in the longitudinal direction, but the hand-cutting property becomes unsatisfactory (hard to cut by hand). Further, when the depth (D) of the recess 5 is larger than 0.3 mm, the hand-cutting property is good, but the tensile strength in the longitudinal direction becomes small, and when the recess 5 becomes extremely deep, the adhesive tape is unexpected when unrolled from the roll. It cuts at some points. The interval (W) between the concave portions 5 is 0.5 to 5 mm, preferably from the viewpoint of the ease of hand-cutting of the adhesive tape.
It is 0.6 to 1.4 mm. The thickness (T) of the base film 1 is generally in the range of 40 to 400 μm, and may be appropriately determined depending on the application and the like.

FIG. 2 illustrates a method of manufacturing the base film 1 having the smooth surface 4 on one side and the specific concave surface 3 on the other side, using the above-mentioned polyolefin as a raw material. After extruding the melted polyolefin resin 11 into a film with an extruder 12, in order to form one surface of the film which has not yet been completely cooled to room temperature into a smooth surface and the other surface into a concave surface, the film-like material is used. It is placed between the squeeze roll 13 and the rubber roll 14.
Here, the squeeze roll 13 is a roll having on its surface a convex squeeze corresponding to the concave shape to be attached to the other surface of the base film, and the rubber roll 14 is a smooth surface to be attached to one surface of the base film. A roll having a smooth shape corresponding to the shape on its surface. Therefore, by pressing the film not yet completely cooled to room temperature with the rubber roll 14 and the squeeze roll 13, the convex shape of the squeeze roll 13 is transferred to the surface of the film, and the concave portion is formed on the other surface according to the present invention. The unstretched base material film 1 made of polyolefin resin is obtained.

The electrode 15 and the treatment roll 16 (having a smooth surface) shown in FIG. 2 have an affinity between the adhesive 2 and the concave surface 3 described later (anchoring property of the adhesive 2 to the concave surface 3. Wetting of the concave surface 3). In order to increase (in relation to the tension), the concave surface 3 of the film is opposed to the electrode 15 side and the concave surface 3 is subjected to corona discharge treatment. The corona discharge treatment is a well-known treatment method, but in the present invention, this treatment is not essential and may be performed as necessary. Regarding the surface wetting tension of the base film 1 (the higher the surface wetting tension, the greater the anchoring property of the adhesive 2), the smooth surface 4 has a surface tension of 30 Dyn / cm or less, and the concave surface 3 has a surface tension of 35 Dyn / cm or more. Is preferred. If the surface wetting tension of the smooth surface 4 is more than 30 Dyn / cm, it becomes difficult to develop from the adhesive tape wound in a roll and blocking phenomenon (even if the smooth surface 4 of the adhesive tape is inconvenient to the adhesive 2). It is not preferable because the surface wetting tension of the concave surface 3 is less than 35 Dyn / cm because the anchoring property of the adhesive 2 to the concave surface 3 is insufficient.

Another method for increasing the affinity between the adhesive 2 and the concave surface 3 is to apply a primer on the concave surface 3. This method is also a well-known method, and a known primer can be used, and examples thereof include a rubber-based primer such as a nitrile rubber and an acrylic resin-based primer. In the present invention, it is not essential to apply a primer, but may be applied as appropriate. Further, the corona discharge treatment method and the primer coating method may be used in combination.

The reinforcing material for the adhesive tape of the present invention is a material such as a non-woven fabric or a split cloth, which are well known materials. Nonwoven fabrics and split fabrics include polyethylene, polypropylene, polyethylene terephthalate, 6-nylon, 6,6-nylon, polyparaphenylene terephthalamide, polyacrylonitrile, vinylon, rayon,
Nonwoven fabrics and split cloths made from hemp, silk, wool and the like can be exemplified. Of these, rayon, polyethylene, polypropylene, and polyethylene terephthalate are preferable from the viewpoint of adhesiveness with the base film, heat resistance, solvent resistance, and the like. These raw materials may be used alone or as a mixture of two or more kinds. When a colored nonwoven fabric or split cloth is used, the nonwoven fabric or split cloth may be colored, or the above raw materials may be colored in advance.

The non-woven fabric may or may not be porous. The amount of the adhesive tape used is preferably 5 to 120 g, and more preferably 8 to 18 g, per area of 1 m ² of the adhesive tape from the viewpoints of hand-cutability, total thickness, touch (softness) of the obtained adhesive tape. As a non-woven fabric made of rayon, which is one of the preferable non-woven fabrics according to the present invention, a non-woven fabric manufactured by Miki Special Paper Co., Ltd. under the trade name of Mikiron (14 g / m ² ) can be obtained.

As the split cloth, the thickness is preferably 50 to 500
Denier, more preferably 70-150 denier yarn width 25
The warp yarn (warp yarn) formed by weaving preferably 5 to 60 yarns per mm, more preferably 15 to 30 yarns, and the thickness is preferably 50 to
500-denier yarns, more preferably 70-200 denier yarns with a width of 25 mm, preferably 5 to 90 yarns, more preferably 15 to
It is recommended to use a split cloth consisting of 40 weft threads. The split cloth is used so that the warp direction of the split cloth is the longitudinal direction of the adhesive tape. If the thickness of the warp exceeds 150 denier (thicker), the hand-cutting property of the adhesive tape becomes unsatisfactory, and if the weft thickness exceeds 500 denier, the surface of the split cloth (with adhesive applied) It becomes difficult to obtain the smoothness of the surface to be coated), and therefore, an unfavorable problem such as a decrease in the adhesive strength of the adhesive tape or an increase in the amount of the adhesive to be applied tends to occur. The thickness of the split cloth is 30 to 500
μm is preferable, and more preferably 80 to 200 μm.
In addition to the warp yarn and the weft yarn, the split cloth may include a yarn woven obliquely with respect to these. As a polyethylene split cloth which is one of the preferred split cloths according to the present invention,
The product name of Nisseki Plastics Co., Ltd. is Nisseki Wallif EX-
24 (48 g / m ² ) cots are available.

The pressure-sensitive adhesive relating to the pressure-sensitive adhesive tape of the present invention may be a pressure-sensitive adhesive known in the field of pressure-sensitive adhesive tapes, and as the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, vinyl ether pressure-sensitive adhesive, silicone pressure-sensitive adhesive, rubber pressure-sensitive adhesive. And the like.
The form of the pressure-sensitive adhesive is not particularly limited, and may be any type such as a solution-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, and a hot-melt-type pressure-sensitive adhesive.

The pressure-sensitive adhesive tape of the present invention is manufactured using the above-mentioned specific substrate film, a reinforcing material such as a nonwoven fabric or a split cloth, and a pressure-sensitive adhesive as essential materials. The method is illustrated below. FIG. 3 shows a base film 1, a non-woven fabric or a split cloth 21, and a solution adhesive 2.
It is an example in the case of producing the adhesive tape of the present invention from the following.
The non-woven fabric 21 or the split cloth continuously supplied from the left side of the figure is first impregnated with the solution adhesive 2 in the pan (dish) 22 and is continuously supplied from the lower side of the figure 23. At the same time, they are pressure-bonded by the roll 24 to form an integrated body composed of both. The solvent contained therein (solvent of the solution adhesive 2) is removed by the dryer 25 to be a solvent-free integrated body (should be the composite layer 6 constituting the adhesive tape). After that, from the upper side of the drawing, the concave surface 3 is pressure-bonded with the roll 26 together with the base film 1 continuously supplied so as to face the integrated body. After being pressure-bonded, the process paper 23 and the adhesive tape are separated from each other, and the recovered process paper 23 and the target adhesive tape are each wound into a roll.

In this manufacturing method, the solution-like adhesive 2
The type of solvent and the concentration of the solution used to prepare
It may be appropriately determined according to the type of the adhesive tape to be manufactured, and the type of the dryer 25 and the drying conditions may be appropriately determined according to the type of the solvent used. In addition, the process paper 23 is used to hold an integrated material including the non-woven fabric or the split cloth 21 and the adhesive 2, and is a well-known material in the production of adhesive tapes and the like. When manufacturing the adhesive tape, the process paper 23 may be appropriately selected. The manufacturing method of FIG. 3 does not include a step of heat-treating the polyolefin resin base film 1, so that there is no possibility of deterioration of the base film 1 due to heat, which is a preferable method for manufacturing the adhesive tape of the present invention. Is.

FIG. 3 shows an example of a manufacturing method using the process paper 23. The process paper supplied in this manufacturing method is shown in FIG.
Replacing 23 (23 in the lower left of the figure) with base film 1 (the upper right of the figure) provides a method for producing an adhesive tape that does not use the process paper 23. In this case, the lower left 23 in FIG. 3 is replaced with the base film 1, and the upper right base film 1 and the lower right process paper 23 in the figure are deleted.

FIG. 4 shows a base film 1 and a non-woven fabric or split cloth.
It is another example of manufacturing the adhesive tape of the present invention from 21 and the adhesive 2. The base film 1 that is continuously supplied from the left side of the figure so that the concave surface 3 faces the nonwoven fabric or the split cloth 21, and the nonwoven fabric or split cloth 21 that is continuously supplied from the upper left side of the figure are overlapped and integrated. It is a thing. Next, the film 2 and the composite layer 6 (nonwoven fabric or split cloth 21 and the pressure sensitive adhesive 2 are mixed with each other by mixing the pressure sensitive adhesive 2 continuously from the upper side of the figure on the monolithic body and then pressing with a roll 31. Layer)
The adhesive tape of the present invention consisting of is wound into a roll. In the manufacturing method of FIG. 4, the adhesive may be a solution adhesive or a non-solution adhesive such as a hot-melt adhesive. When using a solution adhesive,
It is advisable to provide a dryer for removing the solvent and the medium in the step after continuously supplying the pressure-sensitive adhesive in the form of a solution onto the above integrated body. When a hot-melt type adhesive whose viscosity is generally higher than that of a solution-type adhesive is used, the manufacturing method of FIG. 4 can be suitably applied to a split cloth but is applicable to a nonwoven fabric. It may be difficult to do. Because the gaps between the fibers of the non-woven fabric are generally smaller than the gaps between the fibers of the split fabric, if the gap between the fibers is too small, the hot-melt adhesive will be difficult to sufficiently penetrate into the non-woven fabric. Is.

The pressure-sensitive adhesive tape of the present invention is generally manufactured in the form of lap winding as shown in FIG. 5 in the same manner as in the case of the conventional pressure-sensitive adhesive tape (the length per roll is, for example, 25 m, 50 m), for example, when a rubber-based adhesive is used as the adhesive, or when the amount of the adhesive applied is large, in order to further improve the developability of the adhesive tape, the outer surface (smooth surface) of the adhesive tape A release agent known for adhesive tape may be appropriately applied onto the above).

[0025]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the scope of the present invention is not limited by these examples. Here, the tensile strength (N / cm) and the tensile elongation (%) in the longitudinal direction of the adhesive tape are JIS-Z.
It is a value measured based on 0237. Further, the hand tearability expresses "linearity of the cut portion" and "easiness of cutting" when the adhesive tape is cut in the width direction only by the hand (fingertip), and is excellent>good> acceptable. The ranking is shown.

Comparative Example 1 A pressure-sensitive adhesive tape obtained by coating only a pressure-sensitive adhesive on the concave surface side of a polyolefin resin substrate film having one surface smooth and the other surface concave is described in JP-A-3- It was manufactured based on the method described in Japanese Patent No. 47885. Density is 0.96g
/ Cm ³ , melt index 7.0g / 10min (190 ℃, 2.1
1 part by weight of 6 kg / cm ² ) polyethylene resin and a density of 0.92
g / cm ³ , melt index 4.0 g / 10 min (190 ° C,
2.16 kg / cm ² ) of 3 parts by weight of polyethylene resin
A molten sheet obtained by extrusion processing at 160-190 ℃, a rubber roll and a squeeze roll (squeezing depth 0.08 m
m, the distance between the diaphragms is 1.2 mm), then it is cooled and solidified, and then the concave surface is subjected to corona discharge treatment with 45 dynes to obtain a base film with a thickness (T) of 0.11 mm. It was

The same pressure-sensitive adhesive as that used in the examples described later was applied to the concave surface of the base film by a roll coater,
After passing through a drying oven set at ˜120 ° C. for 5 minutes, an adhesive tape was obtained. Table 1 shows the physical properties of the obtained adhesive tape. Example 1 From the base film used in Comparative Example 1, a non-woven fabric manufactured by Miki Tokushu Paper Co., Ltd. under the trade name of Mikiron (14 g / m ² ), and an acrylic adhesive, An adhesive tape was manufactured by the manufacturing method shown. The pressure-sensitive adhesive used was an acrylic pressure-sensitive adhesive manufactured by Saiden Chemical Co., Ltd. under the trade name of # AT-40D (pressure-sensitive adhesive in the form of a solvent. The solvent was a mixed solvent of 9: 1 (by weight) of toluene and ethyl acetate. Is 45% by weight) 1
A pressure-sensitive adhesive comprising 00 parts by weight and 0.5 part by weight of a polyisocyanate cross-linking agent manufactured by Nippon Polyurethane Co., Ltd. under the trade name of Coronate L75, and the coating amount of the adhesive is 50 g (solids) per 1 m ² of the base film. Minute conversion). As the process paper, the product name of Shin Oji Paper Co., Ltd. is Kraft Calpack paper.
A process paper of 73DX (73 g · m ² ) was used. Table 1 shows the physical properties of the obtained adhesive tape.

Example 2 The same as Example 1 except that the nonwoven fabric of Example 1 was replaced with a split cloth made by Nisseki Plastics Co., Ltd. under the trade name of Nisseki Wallif EX-24 (48 g / m ² ). An adhesive tape was manufactured. Table 1 shows the physical properties of the obtained adhesive tape. Example 3 An adhesive tape was prepared in the same manner as in Example 1 except that the nonwoven fabric of Example 1 was replaced with a split cloth manufactured by Nisseki Plastics Co., Ltd. under the trade name of Nisseki Wallif EX-28 (53 g / m ² ). Was manufactured. Table 1 shows the physical properties of the obtained adhesive tape.

Example 4 An adhesive tape was produced in the same manner as in Example 1 except that the non-woven fabric of Example 1 was replaced with a polyethylene terephthalate non-woven fabric (18 g / m ² ) manufactured by Uma Paper Co., Ltd. Table 1 shows the physical properties of the obtained adhesive tape.

[0030]

According to the present invention, a non-woven fabric or a split cloth and a pressure-sensitive adhesive are formed on the concave surface of an unstretched polyolefin resin base film having one surface smooth and the other concave. By forming the composite layer, it is possible to obtain an adhesive tape in which the elongation in the longitudinal direction of the adhesive tape is reduced without impairing the hand-tearability of the adhesive tape in the width direction to the extent of a problem. As is clear from Examples and Comparative Examples, a nonwoven fabric (Example 1
And 4) or the split tape (Examples 2 and 3) and the adhesive layer on which the composite layer formed of the adhesive is formed, the elongation in the longitudinal direction is the adhesive tape in which only the adhesive is applied on the concave surface of the base film. It is significantly smaller than the elongation in the longitudinal direction of (Comparative Example 1), and the tearability in the width direction of the adhesive tape is not impaired. Therefore, the pressure-sensitive adhesive tape of the present invention can be preferably used, for example, for masking in painting.

[0031]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a perspective view of an adhesive tape of the present invention.

FIG. 2 is a diagram showing a method for producing a base film according to the present invention.

FIG. 3 is a diagram showing a production method for producing the adhesive tape of the present invention using process paper.

FIG. 4 is a diagram showing a production method for producing an adhesive tape of the present invention comprising a base film and a non-woven fabric or a split cloth and an adhesive, without using process paper.

FIG. 5 is a perspective view of a pressure-sensitive adhesive tape obtained by applying a pressure-sensitive adhesive to a conventional substrate film and winding the tape in a roll shape.

FIG. 6 is a perspective view of a base film of a conventional adhesive tape.

FIG. 7 is a perspective view of a conventional adhesive tape.

[Explanation of symbols]

 1 ... Substrate film 2 ... Adhesive 3 ... Concave surface 4 ... Smooth surface 5 ... Recessed part 6 ... Composite layer 11 ... Polyolefin resin 12 ... Extruder 13 ... Drawing roll 14 ... Rubber roll 15 ... Electrode 16 ... Treatment roll 21 ... Nonwoven fabric or split Cloth 22… Bread (dish) 23… Process paper 24… Roll 25… Dryer 26… Roll 31… Roll

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 7/04 JHW C09J 7/04 JHW JJA JJA

Claims (1)

[Claims] 1. A smooth surface on one side and a depth of 0.03 to 0.3 mm perpendicular to the longitudinal direction of the adhesive tape on the other side and a spacing of 0.5 to 5
The base film made of an unstretched polyolefin resin formed on the surface having a concave portion which is a score parallel line of mm and a composite layer composed of a non-woven fabric or a split cloth reinforcing material and an adhesive on the surface having the concave portion. Adhesive tape.