JPH07331200A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive adhesive tape which can be cut easily and manually in the weft direction to give a unifuzzy cut surface by using flat yarns made by stretching a composition containing a polyolefin synthetic resin and a polystyrene synthetic resin as the warp. CONSTITUTION:This tape used for packaging or curing is made by laminating a synthetic resin layer on base cloth in which the warp is flat yarn made by stretching a resin composition containing 100 pts.wt. polyolefin synthetic resin and 3-20 pts.wt. polystyrene resin and the weft is flat yarn made of a polyolefin synthetic resin and forming a pressure-sensitive adhesive layer on this surface. It is desirable for practical purpose that the warp flat yarn has a fineness of 100-800d, a tenacity of 4.5-6g/d and an elongation of 10-18%, and even when the fineness is relatively high, a tape having good manual cuttability and giving a fine cut surface can be obtained. It is desirable that the weft has a fineness one to three times as high as that of the warp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an adhesive tape, which is preferably used as a packing material and a curing material, has good hand-cutting property, and is beautiful by suppressing fuzz on a fractured surface. Is.

[0002]

2. Description of the Related Art Adhesive tapes are adhered by a light pressure of a fingertip or the like without being assisted by a solvent or heat, and basically consist of a tape base material and a pressure sensitive adhesive layer. Acrylic, rubber, silicon, etc. are selected as the pressure-sensitive adhesive depending on its application and function.In addition to the conventional kraft paper and film, the tape base also has scissors and cutters in the latitudinal direction of the adhesive tape. In order to obtain an easy-to-use adhesive tape that can be easily cut linearly by hand without using, woven fabric-treated ones have also been found.

Woven fabrics include natural spun yarn and synthetic spun yarn,
Various tape bases using multifilaments for warp and weft, and various inexpensive and high-quality adhesive tapes using flat yarn cloth as a tape base have been disclosed.
Specifically, the one that has a plastic film layer formed on one surface of a plain woven flat yarn cloth and an adhesive layer on the other surface (Jitsuko Sho 50-30362), or both sides of the flat yarn cloth. Some of them have a plastic film layer formed and an adhesive layer provided on one side (Jpn. Kokoku Sho 51-28352, Kokoku Sho 54-4547).

In order to improve the hand-cutting property of the adhesive tape in the weft direction, the warp and weft yarns each form a first laminate layer on one side of the cross of the flat yarn having a specific fineness, and further a second laminate is formed on the surface thereof. A layer formed with an adhesive layer on the other side (Japanese Patent Publication No. 1-19718), or warp and weft yarns are formed so that a laminating layer is bonded to the front and back surfaces of a flat yarn of a specific fineness. There was an adhesive layer provided on the top (Japanese Patent Publication No. 41189).

These tape base materials impart appropriate heat deterioration to the warp during the heat treatment of the laminate coating to improve the hand tearability of the adhesive tape in the weft direction. Therefore, a low fineness flat yarn is used for the warp. It has to be used, and low-fineness flat yarns have a problem in that they are inferior in economic efficiency of production and weaving efficiency. In addition, reducing the number of warp threads to be driven has a drawback that the tensile strength of the adhesive tape as a whole in the warp direction is lowered and the adhesive tape is inadvertently broken by an impact during use. Furthermore, although a laminate layer is formed to fix the texture of the base cloth, the warp flat yarn is not reliably broken along the cut surface, and it cannot be said that the cut end is beautiful. .

[0006]

Therefore, in the present invention, sufficient strength in the warp direction, good hand-cutting property in the weft direction, and good quality with a beautiful cut surface free of fluff due to oblique cracking of the warp yarn are obtained. The purpose of the present invention is to provide an adhesive tape.

[0007]

According to the present invention, there is provided a base cloth 2 formed by using a polyolefin synthetic resin flat yarn for both warp and weft, and a laminate coating layer 3 laminated on one side or both sides of the base cloth 2. In a pressure-sensitive adhesive tape comprising a tape base material and a pressure-sensitive adhesive layer 4 provided on at least one laminate coating layer surface, the warp yarns constituting the base cloth 2 are based on 100 parts by weight of the polyolefin synthetic resin. And a stretched flat yarn obtained from a resin composition containing 3 to 20 parts by weight of a polystyrene-based synthetic resin.

In the above-mentioned structure, the polyolefin synthetic resin flat yarn used for the warp and the weft of the base cloth 2 is a synthetic resin which is heated and melted in a cylinder, and is then in an amorphous state from a die by a T die flat method or an inflation method. After being cooled, the film extruded in (1) is slit into a narrow width, stretched and oriented about 2 to 8 times in the machine direction by a hot plate or a heat roll, and then heat treated to obtain a flat yarn.

The synthetic resin used as the main component of the flat yarn is ethylene, propylene, 1-butene or 4-methyl-1-pentene because of its stable quality in continuous production, low cost and economical mass production. A polyolefin-based synthetic resin composed of a homopolymer or an intercopolymer of an α-olefin or a copolymer of the α-olefin with another comonomer is adopted.

Here, the warp is made of a resin composition in which a polystyrene synthetic resin is mixed with a polyolefin synthetic resin, and the polystyrene synthetic resin is specifically polystyrene, modified polystyrene, styrene-butadiene copolymer, Examples thereof include homopolymers and copolymers of styrene and its derivatives, such as styrene-acrylonitrile copolymers and styrene-butadiene-acrylonitrile copolymers. The polystyrene-based synthetic resin having a melt flow rate (MFR) of 1 to 20 g / 10 min. Is particularly preferably selected in terms of fluidity, dispersibility and strength.

A stretched flat yarn produced from a resin composition obtained by blending a polyolefin-based synthetic resin and a polystyrene-based synthetic resin has a tensile strength / elongation in the warp direction as compared with a flat yarn of polyolefin alone, The tear strength in the weft direction can be reduced, and the fracture surface can be cut linearly perpendicular to the yarn length direction.

The compounding amount of the polystyrene-based synthetic resin is 3 to 20 parts by weight, more preferably 5 to 10 parts by weight, based on 100 parts by weight of the polyolefin-based synthetic resin. If the amount is less than 3 parts by weight, proper tear strength and good fracture surface cannot be obtained,
If it exceeds 20 parts by weight, the dispersion of the styrene-based synthetic resin becomes insufficient, phase separation occurs, and mechanical properties such as tensile strength and elongation are unnecessarily reduced, resulting in poor practicability.

In the conventional adhesive tape of flat yarn woven fabric, the fineness of the warp is 50 to 250 dr in consideration of the hand-cutting property.
Although it uses a flat yarn of a certain degree. Low-fineness flat yarns tend to be inferior in production economy and weaving efficiency. Therefore, in the present invention, by using the polyolefin synthetic resin flat yarn in which the polystyrene synthetic resin is mixed with the warp, the substantial fineness range of the warp can be expanded to the high fineness side. Specifically, warp flat yarns with a fineness of 100 to 800 dr become practical, more preferably with a fineness of 200 to 500 dr, strength of 4.5 to 6.0 g / d and elongation of 10 to 18%.
belongs to. This is set in consideration of flexibility and smoothness as an adhesive tape, but even a relatively high-definition tape can exhibit sufficiently good hand-cutability and a beautiful cut surface. This is a feature of the present invention.

The flat yarn used for the weft yarn is a flat yarn made of polyolefin synthetic resin, and the fineness thereof is not particularly limited, and it is desirable that the fineness is from the same fineness as the warp yarn to about 3 times higher fineness. This is because it has sufficient strength to prevent oblique cracks so that it can be cut straight along the weft yarns located in the weft direction of the adhesive tape, and it is preferable from the viewpoint of appearance as a tape base material.

Each of the warp and weft flat yarns is woven into a base fabric 2 by a conventional loom such as a sruther type loom or a water jet loom, and the driving density is preferably about 10 to 35 yarns / inch. In addition, the warp yarns have a spacing of about 0.3 to 2.5 mm and the weft yarns have a spacing of about 0.1 to 2.0 mm to increase the binding force of the warp and weft yarns by a laminating coating in the subsequent process to obtain an appropriate warp direction tensile strength and weft. It has directional tear strength and exhibits a good appearance and a beautiful cut surface.

In the present invention, the laminate coating layer 3 is laminated on one side or both sides of the base cloth 2 for the surface smoothness of the tape base material and the binding of the warp and weft threads. As the laminate resin, a polyolefin-based synthetic resin of the same type or the same type as the main component of the flat yarn is preferably used.

As the laminating method, known techniques such as an extrusion laminating method, a dry laminating method and a thermocompression laminating method can be adopted. However, the laminating resin is melted in a molten state in order to penetrate into the woven tissue and form a tough coating layer. Since it is a layered product and can be processed at a higher speed, it is most preferred to be laminated on both surfaces of the base fabric by an extrusion laminating method. Here, the thickness of the laminate coating layer 3 can be arbitrary, but is preferably 15 to 40 μm.

Further, within the range not departing from the gist of the present invention, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, flame retardants, colorants, and fillers are included in synthetic resins used for flat yarns and laminate coatings. Various additives such as the above can be added and blended in a predetermined amount.

The pressure-sensitive adhesive layer 4 is formed on at least one laminated coating layer surface of the tape base material thus obtained to form the pressure-sensitive adhesive tape shown in FIG. 1. The pressure-sensitive adhesive is an acrylic type, a silicon type, A known material such as a vinyl-based material, a natural rubber-based material, or a synthetic rubber-based material may be adopted, and a predetermined basis weight may be applied for each application.

The adhesive tape of the present invention preferably has a strength in the warp direction of 35 kgf / 5 cm or more and an elongation of 10 to 15%. It is assumed that if the strength is less than 35 kgf / 5 cm, it will be difficult to sufficiently withstand the strength as a packaging material, and if the elongation is less than 10%, accidental breakage due to impact easily occurs, This is because if it exceeds 15%, the hand-cutting property is deteriorated and fuzz is easily generated on the cut surface.

[0021]

In the present invention, attention is paid to the resin composition of the flat yarn used as warp in the base fabric 2 of the pressure-sensitive adhesive tape, and a resin in which a predetermined amount of polystyrene-based synthetic resin is blended with the main component being polyolefin-based synthetic resin. It is characterized by comprising a composition, whereby the tear strength in the weft direction is appropriately reduced while the tensile strength and elongation in the warp direction are almost maintained, and the fracture surface is in the yarn length direction. Can be cut linearly perpendicular to.

[0022]

EXAMPLES The adhesive tape according to the present invention will be described in the following examples.

Polypropylene (MFR = 1.7) was selected as the main component polyolefin-based synthetic resin, polystyrene (MFR = 3.0) was selected as the polystyrene-based synthetic resin, and the compounding amount of polystyrene was 0 parts by weight per 100 parts by weight of polypropylene. 1.5 parts by weight, 3 parts by weight, 10 parts by weight, 20 parts by weight, and 25 parts by weight of the respective resin compositions added and blended,
Melting temperature of 25 from circular die by inflation method
Extruded in an amorphous state at 0 ° C, cooled to form a tubular film, then chopped into a tape, and drawn by a hot roll drawing method at a drawing temperature of 130 ° C, an annealing temperature of 138 ° C, and a draw ratio.
It was drawn at 4.8 to 6.2 times to obtain warp flat yarns having fineness of 200dr, 350dr and 500dr.

Further, weft flat yarns of polypropylene alone having a fineness of 350dr and 500dr were obtained by the same method.

FIG. 1 shows a cross section of the adhesive tape 1 of the present invention. A warp and a weft are combined and woven in a plain weave structure using a through-saw loom to form a base fabric 2, and each base fabric 2 is laminated and coated. Polypropylene for forming layer 3
(MFR = 22.0) at a melting temperature of 280 ° C. by an extrusion laminating method with a thickness of 20 μm as a first laminating layer on one side,
After forming a tape base material on the other surface with a thickness of 38 μm as a second laminate layer, after subjecting the first laminate layer surface of this tape base material to a back surface treatment, after performing a corona discharge treatment on the second laminate layer surface A pressure sensitive adhesive layer 4 made of synthetic rubber was provided to obtain an adhesive tape 1.

Table 1 shows the constitutions of the base fabrics of the adhesive tapes produced as the above-mentioned Examples and Comparative Examples.

[0027]

[Table 1]

The performances of the adhesive tapes of Examples and Comparative Examples thus obtained are summarized in Table 2 in terms of tensile strength and elongation in the warp direction, tear strength in the weft direction, and hand tearability. The tensile strength and elongation are measured according to JIS-L1096, and the tear strength is measured according to JIS-L1096.
P8116, hand-cutting is easy to cut and fuzz on the cut surface.
(○: easy to cut, no fluff, Δ: cut by hand but fluff is partially generated, ×: difficult to cut and many fluffs).

[0029]

[Table 2]

From Table 2, this Example has a sufficient strength in the warp direction as an adhesive tape, is improved in tear strength in the weft direction, and can be easily torn by hand. It is recognized that the tape is linear and has no fluff and is of good quality. On the other hand, in Comparative Example, a flat yarn with a low polystyrene content was used for the warp.
(Comparative Examples 1, 2, 4, 5, 7, 8) used flat yarns having large tear strength in the weft direction and poor hand-cutability of the adhesive tape, and containing a large amount of polystyrene (Comparative Examples 3, 6, 9). )
The production efficiency in the spinning process of the flat yarn itself and the weaving process of the base fabric is never good. In addition, the adhesive tape has low tensile strength and elongation in the longitudinal direction,
It was unsuitable as an adhesive tape for curing material.

Examples in which various polystyrene-based synthetic resins are used instead of polystyrene shown in Examples 1 to 9 are shown in Examples 10 to 13 in Table 3. In these examples, suitable ones were extracted in the blending amount of the polystyrene-based synthetic resin to the polyolefin-based synthetic resin, and the warp fineness of 350 dr,
The weft yarn fineness is 500dr, and the driving density is 18 × 12 yarns / inch.

[0032]

[Table 3]

[0033]

As described above, according to the present invention, it is not necessary to make the warp flat yarns constituting the base fabric to have an extremely fine and low weaving degree, and the base fabric at a level suitable for production and weaving efficiency can be obtained. It is possible to obtain, the adhesive tape using this base cloth,
The adhesive tape is of good quality and has sufficient strength in the warp direction, good hand tearability in the weft direction, and a beautiful cut surface free of fuzz due to oblique cracking of the warp yarn.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an adhesive tape of the present invention.

[Explanation of symbols]

 1 Adhesive tape 2 Base cloth 3 Lamination coating layer 4 Pressure-sensitive adhesive layer

Claims (1)

[Claims] 1. A tape base material comprising a base cloth 2 formed by using a polyolefin synthetic resin flat yarn for both warp and weft, and a synthetic resin laminate coating layer 3 laminated on one side or both sides of the base cloth 2. A pressure-sensitive adhesive tape which is formed and has a pressure-sensitive adhesive layer 4 provided on at least one layer of a laminated coating layer, wherein the warp yarns constituting the base cloth 2 are made of polystyrene-based synthetic resin based on 100 parts by weight of polyolefin-based synthetic resin. An adhesive tape, which is a stretched flat yarn obtained from a resin composition containing 3 to 20 parts by weight.