JPH0860107A - Kraft adhesive tape - Google Patents

Abstract

PURPOSE: To obtain the tape not causing the moisture absorption of the kraft paper and the adhesive layer even after stored for a long period of time, and capable of being reclaimed and reutilized without impairing the appearance and the adhesive performance and without causing side sticks by disposing a releasing layer and an aqueous dispersion type adhesive on the water-repelling layer and the other layer of specific kraft paper, respectively. CONSTITUTION: This tape is produced by disposing releasing paper on the water- repelling layer surface of kraft paper (preferably having a basis weight of 50-100g/m<2> ) having an intelayer strength of >=100g/15mm, a sizing degree of >=12sec, and an air-permeability of >=12sec and having the water-repelling layer on one surface, and further disposing an aqueous dispersion type adhesive layer (e.g. the emulsion of an acrylic resin, vinyl chloride resin or vinylidene chloride resin) on the other surface. The water-repelling layer includes the layers of wax, fatty acid derivative, synthetic resin, silicone, fluoro resin, chromate and vinylidene chloride latexes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kraft pressure-sensitive adhesive tape which is free from side stick during storage and is suitable for recycling.

[0002]

2. Description of the Related Art Conventionally, kraft adhesive tapes used for sealing cardboard boxes and the like are polyethylene-laminated on the side opposite to the kraft paper surface provided with an adhesive layer to make them peelable, and the laminated surface is coated with silicone or the like. Peeling treatment is applied. However, in order to reuse the kraft paper as the base material, the laminated polyethylene film cannot be separated from the kraft paper, which is an obstacle to the recycling work. Therefore, in place of the polyethylene laminate, a water-dispersible or water-soluble substance such as clay or poval is coated as a sealing layer, and the coated surface is subjected to a peeling treatment. A water-soluble adhesive is also used to recycle the kraft adhesive tape.

[0003]

As described above, when the kraft paper coated with the water-dispersible or water-soluble substance is regenerated, the coating agent is dispersed / precipitated in water or dissolved in water. It is possible to separate However, since such a coating layer does not have moisture resistance like the polyethylene laminate layer, the kraft paper absorbs moisture and swells through the coating layer during storage, resulting in wrinkles, which results in adhesiveness to the adherend and the product. Looks worse.

Further, even when the kraft paper is stored for a long time in a high humidity state, the kraft paper absorbs moisture through the coating layer to cause wrinkles, which deteriorates the appearance of the product and the workability when the adhesive tape is used. There is a problem that the adhesive absorbs moisture through the product, stickiness (hereinafter referred to as “side stick”) is generated on the side surface of the rolled product, and the products adhere to each other.

When a solvent-based pressure-sensitive adhesive is used, even if there is no polyethylene laminate layer, the pressure-sensitive adhesive layer itself is non-water-soluble, which is an obstacle to the regeneration treatment. In addition, since an organic solvent is used, a solvent gas is generated during manufacturing, which is not preferable in the working environment.

The present invention solves the above-mentioned problems of the prior art, the kraft paper and the adhesive layer do not absorb moisture even when stored for a long period of time, the appearance and adhesive performance are not impaired, side sticks do not occur, and An object of the present invention is to provide a kraft pressure-sensitive adhesive tape that can be recycled and does not generate solvent gas during production.

[0007]

The kraft pressure-sensitive adhesive tape of the present invention has an interlayer strength of 100 g / 15 mm or more and a size degree of 12.
Seconds or more, air permeability of 12 seconds or more, a release layer is provided on the water-repellent layer surface of the kraft paper having a water-repellent layer on one surface,
A water-dispersed pressure-sensitive adhesive layer is provided on the other surface of the kraft paper.

The kraft paper as the support of the kraft pressure-sensitive adhesive tape of the present invention is preferably subjected to a Clupak process, which may be exposed or unbleached. Kraft paper has an interlaminar strength of 10
Use 0g / 15mm or more. If the interlaminar strength is lower than this, the strength as a tape substrate is weak and it cannot be put to practical use. For example, a problem such as tearing of the adhesive tape occurs during the packaging work of the cardboard box.

Further, the sizing degree and air permeability of the kraft paper must be 12 seconds or more. If each is less than 12 seconds, the liquid absorbency becomes large, and the amount of the water repellent and the release agent applied to the liquid needs to be the designed amount or more. In addition, the interlayer strength of the kraft paper is reduced.

The above-mentioned interlayer strength is TAPPI No. 19, the size degree is a value measured according to JIS P8122, and the air permeability is a value measured according to JIS P8117.

The kraft paper used in the present invention has a basis weight of 50 to 50.
It is preferably 100 g / m ² . Basis weight is 5
If it is less than 0 g / m ² , the strength is low and the film is easily torn, which is not practical, and the values of the interlayer strength, size and air permeability cannot be obtained. ^{On the other hand} , if it exceeds 100 g / m ² , the hand-cutting property becomes poor and it becomes difficult to use.

The water repellent layer on one side of the kraft paper is formed by secondary processing such as impregnation of the kraft paper or surface coating. Examples of the water repellent layer include water repellent agents such as wax, fatty acid derivatives, synthetic resin, silicone, fluorine, chromic acid and vinylidene chloride latex.

A release layer is formed on the surface of the water repellent layer. The release layer is permeable to water, but the water repellent layer blocks the permeation of water to prevent moisture absorption of the kraft paper. The release agent used as the release layer is not particularly limited, generally used solvent-based, water-based,
Solvent-free silicone-based or long-chain alkyl group-containing organic release agents can be used.

In order to improve the sealing effect of the release agent-coated surface of the kraft paper, applying a sealing agent or subjecting the kraft paper to a super calendering process may be carried out by using a water repellent agent and a release agent for the kraft paper. Impregnation is reduced, and the amount of these used can be further reduced.

In the kraft adhesive tape of the present invention, a water-dispersible adhesive is used as an adhesive in the form of an emulsion of acrylic resin, vinyl acetate, vinylidene chloride, or the like. Moisture is absorbed by kraft paper when the water-dispersed adhesive is applied to kraft paper. Dispersoids do not enter the inside of kraft paper, but accumulate in layers on the surface. When this is dried by heating, the absorbed water is forcibly discharged through the dispersoid layer, and the dispersoid solidifies to form a film on the kraft paper surface. Once the water has been discharged, the water repellent layer prevents the water from entering the kraft paper, and does not absorb moisture, thus preventing wrinkles.

[0016]

[Function] Since the kraft paper has an interlaminar strength of 100 g / 15 mm or more, it has sufficient strength as an adhesive tape substrate,
Since the sizing degree and the air permeability are respectively 12 seconds or more, the liquid absorbency is low, the amount of the water repellent agent and the release agent used is small, and the polyethylene laminate layer is not present, so that it can be recovered and reused. Also, due to the size and air permeability of the kraft paper and the water-repellent layer provided on one side of the kraft paper, the kraft paper does not absorb moisture even when it is stored in a place with high humidity, so wrinkles do not occur, and the appearance and adhesiveness There is no side damage and no side stick. Furthermore, since a water-dispersed pressure-sensitive adhesive is used, no solvent gas is generated when the pressure-sensitive adhesive is dried, and the working environment is good.

[0017]

【Example】

(Example 1) Basis weight 73 g / m ² , interlayer strength 150 g / 1
A special fluorinated water repellent (Sumitomo Chemical Co., Ltd., trade name: Sumirez Resin FP-110) having a size of 5 mm, a size of 20 seconds, and an air permeability of 20 seconds is impregnated with a kraft-coated kraft paper. Solventless silicone on one side (Shin-Etsu Chemical Co., Ltd., trade name: KNS-316, viscosity 500 cp
s) is applied and cured at ² g / m ² and an acrylic resin emulsion adhesive (ROHM) is applied to the other surface of the kraft paper.
& HAAS, trade name: Adhesive E-
3189) is applied and dried at 85 g / m ² .

(Example 2) A special synthetic resin water repellent (manufactured by Hyundai Kagaku Kogyo Co., Ltd., trade name: Lipax A-24) was applied to the surface of the same Krappak processed kraft paper used in Example 1.
0) is coated, and the coated surface is coated with the same solventless silicone as used in Example 1 at 2 g / m ^2.
The acrylic resin emulsion adhesive (trade name: SK Dyne E-3303, manufactured by Soken Chemical Co., Ltd.) was applied and dried on the other surface of the kraft paper at 95 g / m ² and dried.

Comparative Example 1 A mixture of 100 parts by weight of Poval (manufactured by Kuraray Co., Ltd.), 100 parts by weight of clay, and 200 parts by weight of water was added to the same surface of the kraft processed kraft paper used in Example 1 to obtain 10 g / m 2. ² Coating and drying, smoothness is 10
It was supercalendered so that it would be 0 seconds. The same solvent-free silicone as used in Example 1 was applied and cured on the coated surface of the above mixture at 1 g / m ² to obtain a substrate. The same adhesive as that used in Example 1 was applied to the surface of the substrate opposite to the solventless silicone-coated surface at 85 g / m ^{2 and} dried to obtain a kraft adhesive tape.

(Comparative Example 2) A substrate obtained by coating and curing the solventless silicone used in Comparative Example 1 at 1.5 g / m ^{2 on} one side of the same Kurpac processed kraft paper used in Example 1. On the other side, a water-soluble acrylic adhesive (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne 1180) was used as an adhesive.
A kraft pressure-sensitive adhesive tape was obtained by coating and drying at 5 g / m ² .

The following items were evaluated for the kraft adhesive tapes of Examples 1 and 2 and Comparative Examples 1 and 2 described above. (1) Appearance at the time of production: The adhesive was applied to kraft paper using a reverse roll, and the appearance immediately after drying was visually observed. (2) Appearance of the product: The appearance of the product after the craft adhesive tape was stored under the following conditions was visually observed. After high humidity (40 ° C, 90% RH, after 1 day) After long time (at room temperature, after 1 month) (3) Side stick: Store the craft adhesive tape as a product under the same conditions as described in (1) above. After that, the degree of the side stick was judged by touching the finger. The above results are shown in Table 1.

[0022]

[Table 1]

It is clear from Table 1 that the results of Examples 1 and 2 are superior to those of Comparative Examples 1 and 2 in all evaluation results.

[0024]

Since the kraft adhesive tape of the present invention has the above-mentioned constitution, the kraft paper has sufficient strength as an adhesive tape base material, the amount of the water repellent and the release agent used is small, and there is no waste. Since there are no layers, it can be recovered and reused. In addition, since the kraft paper does not absorb moisture even if it is stored in a place of high humidity for a long period of time, wrinkles do not occur, the appearance and adhesiveness are not impaired, and side sticks do not occur. Furthermore, since a water-dispersed adhesive is used, solvent gas is not generated when the adhesive is dried, and a good working environment can be maintained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C09J 7/02 JKQ

Claims (1)

[Claims] 1. A kraft paper having an interlayer strength of 100 g / 15 mm or more, a size degree of 12 seconds or more, and an air permeability of 12 seconds or more, and a water-repellent layer provided on one surface of which is provided with a release layer, A kraft pressure-sensitive adhesive tape, characterized in that a water-dispersed pressure-sensitive adhesive layer is provided on the other surface of the kraft paper.