JP2007270000A - Substrate for pressure-sensitive adhesive tape and pressure-sensitive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that a warp yarn near an end just before completion of breaking is broken in a state of the resultant elongated yarn like projecting hair from one end of the cut face without being directly broken on one straight line and causing an unsightly state of the cut face (a projecting hair phenomenon) during tearing of a pressure-sensitive adhesive tape with a hand. <P>SOLUTION: A knitted fabric 3 employing staple yarns as the warp yarns 1 and yarns made of a polyester resin as weft yarns 2 is used. The surface of the knitted fabric 3 is subjected to a treatment with an anchor coating agent containing an ethylene-vinyl acetate copolymer. A laminate layer 5 of a polyethylene film is provided on one or both surfaces of the knitted fabric having the anchor coating treatment layer 4 to form a laminated substrate 6. A pressure-sensitive adhesive layer 8 is provided on one surface of the substrate 6. A back surface treating layer 7 is provided on the polyethylene laminate layer 5 on the other surface to afford the pressure-sensitive adhesive tape 10 having hand-cutting properties. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive tape substrate for pressure-sensitive adhesive tapes used for packing, bundling, joining, and the like, and a pressure-sensitive adhesive tape using the substrate.

Conventionally, the base material of adhesive tape used for sealing, bundling, joining, temporarily fixing curing sheets, etc., is a cloth made by laminating polyethylene on warp and weft yarns made of suf yarn because of its durability and good cutting ability. A base material (sufu cloth base material) is used.
However, the sufu cloth base material has a problem that a cutting line may run in the vertical direction in the middle when the ends are pinched with both hands and teared in the horizontal direction, resulting in a lightning-like cut surface.

Therefore, in order to solve this problem, the warp yarn having good hand-cutting properties is used as it is, and the weft yarn is a flat yarn made of a thermoplastic resin such as polypropylene or polyethylene which is stronger than the suf yarn, and at least one side is made of polyethylene. Is used. (Patent Document 1)
However, in such a base material 11, as shown in FIG. 4, the warp yarns near the end immediately before being completely cut when tearing by hand are not cut in a straight line in the tearing direction as a result, resulting in a cut surface. This causes a problem that the cut surface becomes unsightly (hereinafter referred to as beard phenomenon).

In order to solve this problem, it has been proposed to perform physical or chemical anchoring on one or both sides of the knitted fabric. Examples of the physical treatment include corona treatment, UV treatment, and sputtering treatment. Examples of the chemical treatment include treatment of applying a resin selected from organic titanium, isocyanate, polyethyleneimine, and polybutadiene. Yes. (Patent Document 2).
Japanese Patent Laid-Open No. 11-335942 JP 2002-294189 A

  In order to further ensure the ability of the adhesive tape to be cut by hand, the present inventors use a knitted fabric that uses a strong polyester resin (PET) yarn as the weft while using a warp as a staple. Various studies were conducted. However, in this knitted fabric, the adhesiveness with the polyethylene resin laminated thereon is insufficient, and the occurrence of whiskers could not be eliminated even by performing the above-described physical or chemical anchor treatment.

  INDUSTRIAL APPLICABILITY The present invention can reliably laminate a polyethylene film on a knitted fabric having warp yarns as staple yarns and weft yarns made of polyester resin (PET), and is effective in generating the above-described whiskers when cut by hand. Therefore, it is intended to obtain a base material that can be suppressed by hand and can be cut by hand smoothly and an adhesive tape using the base material.

  As a result of studying and researching various resins with respect to the anchor coat agent interposed between the knitted fabric and the polyethylene film, the present inventor has obtained a treatment agent comprising an ethylene vinyl acetate copolymer (EVA). As a result, it has been found that the above-described problems can be improved, and the present invention has been completed based on such findings.

The present invention provides a knitted fabric in which warp yarn is made of suf yarn and weft yarn is made of polyester resin, and a laminate is formed by laminating a polyethylene film on one or both sides of the woven fabric. It is the base material for adhesive tapes which processed the anchor coat agent containing an ethylene vinyl acetate copolymer with respect to the said knitted fabric so that it might interpose between films.
In addition, a back treatment layer is formed on the polyethylene film located on one side of the base material for the adhesive tape, and an adhesive layer is formed on the knitted fabric or polyethylene film on the other side of the base material. It is a tape.

In an adhesive tape base material in which polyethylene is laminated to a knitted fabric in which warp yarn is made of suf yarn and weft yarn is made of PET yarn, anchor coating is applied to the knitted fabric with a treatment liquid containing EVA, so that the weft yarn is strong and handy. It is possible to obtain a base material that has good cutting properties and has high adhesion between the knitted fabric and the polyethylene film and can suppress the occurrence of whiskers as much as possible when it is cut by hand.
Moreover, an easy-to-use adhesive tape can be obtained as a hand-cut tape using this substrate.

As for the knitted fabric 3 used for the base material 6, a staple yarn is used for the warp 1, but those having a fineness of 10 to 1000 denier, preferably 20 to 500 denier are the strength of the base material, hand cutting property, elongation, etc. Good in terms of balance.
When the warp fineness is less than 10 denier, the base material strength required for packing and curing adhesive tapes cannot be obtained. It becomes difficult to obtain sex.

  The number of warps to be driven is preferably in the range of 10 to 60 yarns / inch (2.54 cm: the same applies hereinafter) in order to obtain an appropriate base material strength and hand cutting ability. When the number of warps driven is less than 10 / inch, the strength of the base material is low, which is not practical, and the distance between the warps is too wide, so that the straightness of the cut end is difficult to occur at the time of hand cutting. On the other hand, if it exceeds 60 / inch, the strength balance in the weft direction will be lost and it will be easily cracked, which is disadvantageous in terms of cost.

  The weft 2 is made of polyester resin and can be used regardless of monofilament, multifilament, flat yarn or the like. This weft has a fineness of 30 to 1000 deniers, preferably 100 to 500 deniers, in view of the balance between hand cutting in the vertical direction and thermal deterioration during lamination. When the fineness of the weft is less than 30 denier, it tends to tear into a hook shape when cut by hand due to the effect of thermal deterioration during laminating, and when it exceeds 1000 denier, There is a tendency to be unable to cut in.

  An anchor coating agent 4 mainly composed of an ethylene vinyl acetate copolymer (EVA) is applied to the knitted fabric 3. This ethylene vinyl acetate copolymer is a copolymer of an ethylene monomer and a vinyl acetate monomer, and an emulsion liquid in which fine particles of the copolymer are dispersed in water is preferably used because of its coatability.

This ethylene vinyl acetate copolymer has a vinyl acetate content of 10 to 90% by weight and a resin film having a melting point of 60 to 200 ° C., preferably 80 to 150 ° C., and a resin solid content of 25 to 70% by weight. % Is suitable for use in view of the flexibility and adhesive strength of the anchor coat film formed.
If the vinyl acetate content is less than 10% by weight, the adhesiveness to the knitted fabric tends to decrease, whereas if it exceeds 90% by weight, the flexibility tends to be lacking, and the flexibility of the anchor coating agent composition is impaired. There is a concern that the low-temperature adhesiveness is lowered.
As such an ethylene vinyl acetate copolymer, as a commercial item, EH-105HH (made by Nitta Gelatin Co., Ltd.) is mentioned, for example.
In addition, tackifiers, waxes, antioxidants and other various additives can be added to the anchor coating agent for the purpose of improving various properties.

The treatment for the knitted fabric 3 with the emulsion liquid of the anchor coat agent mainly composed of EVA is performed on at least one side or both sides to which the polyethylene laminate is applied in the next step. Examples of the coating method include dipping, and the coating amount is preferably in the range of 1 to ²⁰ g / m ² in terms of solid content.

A laminated layer 5 of a polyethylene film is formed on the knitted fabric 3 that has been subjected to the anchor coating treatment 4. As the polyethylene, high density polyethylene resin is preferably in the range melting point of about 130 to 135 ° C., at a lamination temperature of 150 to 260 ° C., 5 to 250 g / ^{m 2,} preferably of adhesion amount of 10 to 100 g / ^{m 2} Laminated in range.
When the adhesion amount is less than 5 g / m ² , the adhesiveness to the knitted fabric is not sufficient, so that the laminate layer is peeled off, and the above-described whiskers phenomenon easily occurs, and good hand cutting properties cannot be obtained. On the other hand, if it exceeds 250 g / m ² , the tear strength becomes too high and good hand cutting properties cannot be obtained.

The base material 6 thus obtained has a tensile strength in the longitudinal and lateral directions of 5 to 2000 N / 25 mm width, preferably 10 to 500 N / 25 mm width, and a longitudinal and lateral tear strength of 0.1 to 25 N, respectively. The laminate is preferably 0.1 to 10 N and has a longitudinal elongation of 5 to 75%, preferably 10 to 30%.
When the tensile strength in the longitudinal and transverse directions is less than 5 N / 25 mm width, the binding strength is poor, which is not practical. On the other hand, when the width exceeds 500 N / 25 mm width, the strength is too strong, so that suitable hand cutting properties are not exhibited.
Further, when the tear strength in the vertical and horizontal directions is less than 0.1 N, it is not practical because it is easily cut by an impact, and conversely, if it exceeds 25 N, suitable hand cutting properties are not exhibited.
Further, when the elongation in the vertical direction is less than 5%, the followability to the adherend is poor, so that it is difficult to stick to the curved surface, and the impact resistance is low. On the other hand, if it exceeds 75%, the elongation is too large, and a suitable hand cutting property cannot be obtained.

  A back treatment layer 7 is formed on the surface of the polyethylene laminate layer 5 formed on the entire surface of the substrate 6. The back surface treatment agent for forming the layer has releasability and can be appropriately selected depending on the type of the pressure-sensitive adhesive layer described below, whether silicon or non-silicon.

An adhesive layer 8 is formed on the opposite surface of the substrate 6 to the back treatment layer 7, thereby forming an adhesive tape 10.
The pressure-sensitive adhesive layer 8 is formed on the knitted fabric 3 when the polyethylene laminate layer 5 is provided only on one side of the substrate 6 (FIG. 2), and the polyethylene laminate layer 5 is provided on both sides of the substrate 6. Is formed on any polyethylene laminate layer 5 (FIG. 3).

The pressure-sensitive adhesive to be used is selected from pressure-sensitive pressure-sensitive adhesives such as rubber-based, acrylic-based, silicon-based, etc., and is usually applied to a thickness in the range of 5 to 200 μm, preferably 10 to 100 μm. Layer 8 is formed.
When the thickness of the pressure-sensitive adhesive layer 8 is less than 5 μm, the initial tackiness is not sufficient, and the adhesion to the rough surface and the adhesion in the winter easily occur. When the thickness exceeds 200 μm, the winding when the pressure-sensitive adhesive tape roll is formed. In many cases, the return becomes too heavy, and the adhesive sticks out of the side surface of the roll, and dust adheres, or the roll side surfaces adhere to each other in the stacked state.

  When the pressure-sensitive adhesive layer 8 and the back treatment layer 7 are provided on the polyethylene laminate layer 5, the surface of the polyethylene laminate layer 5 is previously subjected to corona treatment and other treatments so as to improve the adhesion between them. It is good to make it.

A knitted fabric 3 was prepared in which a warp 1 having a fineness of 130 denier and a fineness of 130 denier was used, and a weft 2 having a PET multifilament having a fineness of 150 denier and having a fineness of 150 denier was driven.
An ethylene vinyl acetate copolymer emulsion (“Gelatin / EH-105HH” manufactured by Nitta Gelatin Co., Ltd., solid content concentration 20%) is used as an anchor coating treatment agent on one side of the knitted fabric 3 and applied by dipping treatment. It was applied so that the solid content was 10 g / m ² and dried at 105 ° C. for 1 minute to obtain an anchor coat treatment layer 4. This anchor coat processing layer 4 was similarly formed on the other surface of the knitted fabric 3.

Next, a film thickness of 30 μm is formed on the other side of the rear surface treatment layer 7 so that the film thickness is 35 μm on the pressure-sensitive adhesive layer 8 side on the double-sided anchor coat treatment layer 4. In this way, a polyethylene laminate layer 5 was formed on both sides to obtain an adhesive tape substrate 6.
After the corona treatment is performed on the polyethylene laminate layer 5 on the back side of the substrate 6, the back treatment layer 7 is formed, and the corona treatment is also performed on the polyethylene laminate layer 5 on the other surface, and then the acrylic emulsion. A pressure-sensitive adhesive was applied to form a pressure-sensitive adhesive layer 8, and this pressure-sensitive adhesive tape 10 was wound up to 25 m to form a pressure-sensitive adhesive tape roll.

(Comparative example)
An adhesive tape roll was obtained in the same manner as in Example except that polyethyleneimine was used as the anchor coat treatment agent.

(test)
Whether the pressure-sensitive adhesive tape roll of the example of 5 cm in width and the pressure-sensitive adhesive tape roll of the comparative example of 5 cm in width are prepared ten by ten, and the beard phenomenon is seen by tearing one by ten times in the width (weft) direction. We examined whether.
Table 1 shows the number of occurrences of whiskers as a result of 100 tearing tests.

(Discussion)
In the examples, whisker phenomenon was hardly observed when the tape was torn by hand, whereas in the comparative example, whisker phenomenon was observed in almost all cases. You can see that

Explanatory drawing of the knitted fabric in the Example of this invention Explanatory drawing of the adhesive tape which performed the anchor coat process on one side of the knitted fabric of FIG. Explanatory drawing of the adhesive tape which performed the anchor coat process on both surfaces of the knitted fabric of FIG. Explanatory drawing showing the occurrence of whiskers when tearing the adhesive tape by hand

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Warp 2 Weft 3 Knitted fabric 4 Anchor coat process layer 5 Polyethylene laminate layer 6 Base material 7 Back surface treatment layer 8 Adhesive layer 10 Adhesive tape 13 Warp of warp

Claims (2)

It has a knitted fabric with warp yarn as a staple yarn and weft yarn as a polyester resin yarn, and a laminate is formed by laminating a polyethylene film on at least one side of the knitted fabric, and is interposed between the knitted fabric and the polyethylene film. A base material for an adhesive tape, wherein the knitted fabric is treated with an anchor coating agent containing an ethylene vinyl acetate copolymer. The adhesive which formed the back surface treatment layer on the said polyethylene film located in the single side | surface of the adhesive tape base material of Claim 1, and formed the adhesive layer on the knitted fabric or polyethylene film of the other surface of the said base material tape.

Images