JPH07268295A - Craft adhesive tape - Google Patents

Abstract

(57) [Summary] [Objective] To provide a kraft pressure-sensitive adhesive tape that can be stored under high humidity without extrusion laminating low-density polyethylene. [Structure] Kraft paper with water-repellent treatment, interlaminar strength of 100g / 15mm or more, size of 12 seconds or more, and air permeability of 12 seconds or more is used as the support 11, and the release agent layer 12 and the other surface are provided on one side. Is provided with an adhesive layer 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kraft adhesive tape used for sealing cardboard boxes.

[0002]

2. Description of the Related Art Conventionally, in a kraft pressure-sensitive adhesive tape in which a release agent layer is provided on one side of a kraft paper support and an adhesive layer is provided on the other side, the adhesiveness between the kraft paper and the release agent is improved. For that purpose, it is known to extrusion laminate low density polyethylene to kraft paper (see, for example, "Adhesive Tape Handbook", page 314, page 314, issued by the Japan Adhesive Tape Industry Association on March 2, 1985). Requires a large-scale device, and the upper limit temperature in the coating process of the release agent is limited, which raises the problem that the manufacturing cost rises. A coating agent is applied to the surface.

[0003]

However, since the kraft pressure-sensitive adhesive tape coated with such a sealing agent on the surface does not have moisture resistance, the support will swell due to moisture absorption when stored under high humidity. There was the problem of becoming sloppy.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a kraft pressure-sensitive adhesive tape which can be stored under high humidity without extrusion laminating low-density polyethylene.

[0005]

The kraft pressure-sensitive adhesive tape of the present invention supports kraft paper which is water-repellent and has 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. The body is characterized by having a release agent layer on one side and an adhesive layer on the other side.

The support of the kraft adhesive tape of the present invention includes:
Interlayer strength 100g / 15mm or more, size degree 12 seconds or more, air permeability
Kraft paper of 12 seconds or more is used. It is desirable that the kraft paper be Kurupack processed.

In the coating treatment and water repellent treatment of the release agent,
Interlayer strength of 100 g / 15 mm or more is necessary so that even if the kraft paper absorbs moisture, the strength does not decrease and the layers do not crack. Sizing degree and air permeability mean that in the coating process of the release agent, the release agent penetrates the back surface of the kraft paper, causing anchor failure at the interface with the adhesive, and adhesive property of the adhesive. The size must be 12 seconds or more and the air permeability must be 12 seconds or more to adversely affect the performance.

Incidentally, the above-mentioned interlayer strength is TAPPI No. 1
9, the size degree was measured according to JIS P8122, and the air permeability was measured according to JIS P8117.

The water-repellent agent for water-repellent treatment of kraft paper is not particularly limited, and examples thereof include wax, fatty acid derivative, silicone, fluororesin, polyvinylidene chloride latex, and the like. Either impregnation or surface coating may be used depending on the water repellent used.

The release agent used for providing the release agent layer on one surface of the support is not particularly limited, and examples thereof include a copolymer of phenylmethylsiloxane and dimethylsiloxane, 2
Silicone-based products such as a condensate of methylphenylsiloxane having a (2-hydroxyethylthio) ethyl group and an acrylic polymer having a hydroxyl group, and a condensate of α, ω-dihydroxypolydimethylsiloxane, triacetoxyvinylsilane and tolylene diisocyanate. Examples include polymers and long-chain alkyl group-containing organic release agents.

The support was processed by applying water repellent treatment to kraft paper and then applying a sealing agent and / or supercalendering to prevent the release agent from penetrating and to reduce the amount used. It may be one.

The pressure-sensitive adhesive used for providing the pressure-sensitive adhesive layer on the other surface of the support is not particularly limited, and examples thereof include natural rubber-based pressure-sensitive adhesives and acrylic-based pressure-sensitive adhesives commonly used for kraft pressure-sensitive adhesive tapes. Can be mentioned.

When a water-soluble or water-dispersible pressure-sensitive adhesive is used as the pressure-sensitive adhesive, the kraft pressure-sensitive adhesive tape of the present invention can be used to recycle the corrugated cardboard. Have advantages.

Examples of the water-soluble pressure-sensitive adhesive include (meth)
Acrylic acid, crotonic acid, itaconic acid, maleic acid, acetic acid, and other carboxyl group-containing monomers, and methyl (meth)
Acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, 2-hydroxy (meth)
Acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dialkylaminoalkylene (meth) acrylate, 2-methoxymethyl (meth)
Acrylic ester such as acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, N-
Copolymers with alkaline monomers such as pyrrolidone, N-vinyl-2-pyrrolidone and vinyl pyridine, water-soluble monomers such as acrylamide, N-methylol acrylamide and vinyl ether, and glycerin, polyethylene glycol, polypropylene glycol, polyether polyols. Examples of the acrylic adhesive include softeners such as sorbitol, polyhydric alcohol derivatives, adhesion enhancers such as polyethylene oxide, polyvalent metal salts, crosslinking agents such as melamine compounds and epoxy compounds.

The method of applying the pressure-sensitive adhesive is not particularly limited, and examples thereof include a bottom feed reverse coater, a top feed reverse coater, a Meyer bar coater and a comma roll coater.

[0016]

In the present invention, since the kraft paper having the interlaminar strength of 100 g / 15 mm or more, the size degree of 12 seconds or more, and the air permeability of 12 seconds or more is used, it does not soak into the back surface when the release agent is applied.
Stable and suitable adhesive properties are expressed. In addition, since it is water repellent, it does not absorb moisture even if it is left under high humidity, and even when a water-soluble adhesive is used, the kraft paper does not absorb moisture, so the adhesive absorbs moisture. It does not melt out to one side, and stickiness on the side surface of the support hardly occurs.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a first embodiment of the kraft adhesive tape of the present invention.

[Example 1] As shown in FIG. 1, a basis weight of 73 g
/ M ² , interlayer strength 150g / 15mm, size degree 20 seconds, air permeability 20
On a Krappak processed kraft paper for seconds, an emulsion type water repellent (“Ox-644” produced by Yushisha Kogyo Co., Ltd.
]) Was impregnated and subjected to a water repellent treatment to obtain a support 11.

2.0 g / m ² of a solvent-free silicone (“KNS-316” manufactured by Shin-Etsu Chemical Co., Ltd.) having a viscosity of 500 cps at 25 ° C. was coated on one surface of the obtained support 1 as a release agent. Then, the release agent layer 12 was provided by curing.

Next, on the other surface of the support 1, 100 parts by weight of a natural rubber adhesive (natural rubber "TPC-1X", 100 parts by weight of "Arcon P-100" manufactured by Arakawa Chemical Industry Co., Ltd. as a tackifying resin, As an antioxidant, 1 part by weight of "Irganox 1010" manufactured by Ciba-Geigy Co., Ltd. is dissolved in 603 parts by weight of toluene).
A pressure-sensitive adhesive layer 13 was provided by coating 150 g / m ² and drying to obtain Kraft pressure-sensitive adhesive tape 1.

Example 2 After applying a mixture of 100 parts by weight of polyvinyl alcohol (manufactured by Kuraray Co., Ltd.), 100 parts by weight of clay, and 200 parts by weight of water to one surface of the support, and applying a sealing treatment. , With super calendering for smoothness
For 100 seconds, the same solventless silicone as in Example 1 was used.
A kraft pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that 1.0 g / m ^{2 was} applied. The smoothness is JIS
Measured according to P 8119.

[Example 3] A special synthetic resin water repellent (“Repax A-240” manufactured by Modern Chemical Co., Ltd.) was applied to the surface of kraft paper that had been subjected to Clupak processing to give it a water repellent treatment. A kraft adhesive tape was obtained in the same manner as in Example 1 except for the above.

[Comparative Example 1] A kraft pressure-sensitive adhesive tape was obtained in the same manner as in Example 2, except that the water repellent treatment was not applied to the kraft paper that had been subjected to the Clupak process.

[Comparative Example 2] The water-repellent treatment was not applied to the Kraupak-processed kraft paper.
A mixture of 150 parts by weight of polyvinyl alcohol (Kuraray Co., Ltd.), 50 parts by weight of clay and 200 parts by weight of water was used, no super calendering was applied, and 1.5 g / m ^{2 of} solvent-free silicone was applied. A kraft adhesive tape was obtained in the same manner as in Example 2 except for the above.

The Examples 1 to 3 and Comparative Examples 1 and 2 obtained as described above were stored for 24 hours under high humidity at 40 ° C. and 90% RH and examined for appearance change due to hygroscopic swelling. It was evaluated visually. The results are shown in Table 1.

[0026]

[Table 1]

Example 4 As a pressure-sensitive adhesive, a water-soluble acrylic pressure-sensitive adhesive (“Cybinol AT-80” manufactured by Saiden Chemical Co., Ltd.) was used.
4 ") was coated at 80 g / m ² to obtain a kraft pressure-sensitive adhesive tape as in Example 1.

Example 5 As a pressure-sensitive adhesive, a water-soluble acrylic pressure-sensitive adhesive (“Cybinol AT-80” manufactured by Saiden Chemical Co., Ltd.) was used.
4 ") was coated at 80 g / m ² to obtain a kraft pressure-sensitive adhesive tape as in Example 2.

Example 6 As a pressure-sensitive adhesive, a water-soluble acrylic pressure-sensitive adhesive (“SKDyne 1180” manufactured by Soken Chemical Co., Ltd.) was used.
A kraft pressure-sensitive adhesive tape was obtained in the same manner as in Example 3 except that g / m ^{2 was} applied.

[Comparative Example 3] A kraft pressure-sensitive adhesive tape was obtained in the same manner as in Example 5 except that the water repellent treatment was not applied to the kraft paper that had been subjected to the Clupak process.

[Comparative Example 4] Clupak-processed kraft paper was not subjected to water-repellent treatment, was not subjected to supercalendering, and was solvent-free silicone 1.5.
A kraft pressure-sensitive adhesive tape was prepared in the same manner as in Example 5, except that g / m ^{2 was} applied and a water-soluble acrylic adhesive (“SKDyne 1180” manufactured by Soken Chemical Industry Co., Ltd.) was applied at 115 g / m ^2. Obtained.

Regarding Examples 4 to 6 and Comparative Examples 3 to 4 obtained as described above, under high humidity of 40 ° C. and 90% RH.
The sample was stored for 24 hours and at 23 ° C. and 50% RH for 1 month, and visually evaluated for changes in appearance due to hygroscopic swelling with time, and for stickiness on the side surface of the support. The results are shown in Table 2.

[0033]

[Table 2]

[0034]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the support absorbs moisture and swells even when it is stored under high humidity even though the low density polyethylene is not extrusion laminated. I won't be fooled. Also, because of the convenience of recycling processing,
Even when a water-soluble pressure-sensitive adhesive is used as the pressure-sensitive adhesive, the side surface of the support is less sticky. In addition, since the upper limit temperature in the processing step is not limited by the presence of the low density polyethylene layer, productivity can be improved by increasing the curing temperature of the release agent and the drying temperature of the pressure-sensitive adhesive.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a kraft pressure-sensitive adhesive tape of the present invention.

[Explanation of symbols]

 1 Craft adhesive tape 11 Support 12 Release agent layer 13 Adhesive layer

Claims (1)

[Claims] 1. An interlayer strength of 100 g / which is treated to be water repellent.
Kraft adhesive tape characterized by using a kraft paper having a size of 15 mm or more, a size degree of 12 seconds or more, and an air permeability of 12 seconds or more as a support, and having a release agent layer on one side and an adhesive layer on the other side. .