JPH09286964A - Hot-melt type tacky agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hot-melt type tacky agent composition having excellent tacky characteristics without any malodor. SOLUTION: This hot-melt type tacky agent composition comprises an α- methylstyrene polymer or a styrene-α-methylstyrene copolymer having 100-120 deg.C softening point as a tackifying component at 100: (20-60) blending ratio of the α-methylstyrene polymer or the styrene-α-methylstyrene copolymer expressed in terms of pts.wt. in the hot-melt type tacky agent composition containing the styrene-based block copolymer as a base polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt pressure-sensitive adhesive composition containing a styrene-based block copolymer as a base polymer, and relates to a hot-melt pressure-sensitive adhesive composition excellent in corrugated cardboard sealability and having no bad odor.

[0002]

2. Description of the Related Art Adhesive tapes have been used for many purposes such as sealing, packing, wrapping and masking.
These adhesive tapes are generally manufactured by applying an adhesive solution prepared by dissolving and mixing an adhesive agent in an organic solvent onto a tape base material such as a film, paper or cloth, and then removing the solvent by drying. However, the use of solvents has problems such as fire, working environment, air pollution, and productivity. Therefore, as a means for solving these problems, a non-solvent type hot-melt pressure-sensitive adhesive has attracted attention and has already been industrialized.

Generally, as a base polymer for hot melt type pressure-sensitive adhesives, mainly styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, or styrene-ethylene-propylene-styrene which is a hydrogenated product thereof. Thermoplastic styrenic block copolymers such as copolymers and styrene-ethylene-butylene-styrene copolymers have been used. Since these styrenic block copolymers form a styrene domain, they exhibit the same high cohesiveness as a crosslinked polymer at room temperature,
Since it flows at temperatures higher than the glass transition temperature of styrene,
It is used in various fields as an adhesive that can be processed with a hot melt coater. An adhesive composition obtained by adding a tackifier or a softening agent such as oil to these thermoplastic polymers is disclosed in JP-B-45-41518.

In the pressure-sensitive adhesive composition described in JP-B-45-41518, a coumarone-indene resin excellent in high temperature characteristics, cardboard retention and cardboard sealability is used as a tackifying component. If used, after applying the pressure-sensitive adhesive using a hot melt coater, an odor characteristic of coumarone-indene resin is generated.

[0005]

An object of the present invention is to use a styrenic block copolymer as a base polymer,
It is an object of the present invention to provide a hot-melt pressure-sensitive adhesive composition which has excellent adhesive properties equivalent to the case of using coumarone / indene resin, in particular, cardboard-retaining property and cardboard-sealing property and has no bad odor.

[0006]

The hot-melt pressure-sensitive adhesive composition of the present invention is a hot-melt pressure-sensitive adhesive composition containing a styrene block copolymer as a base polymer.
As a tackifying component, it contains an α-methylstyrene polymer or a styrene-α-methylstyrene copolymer having a softening point of 100 to 120 ° C., and contains a styrene block copolymer and the α-methylstyrene polymer. It is characterized in that the compounding ratio with the polymer or the styrene-α-methylstyrene copolymer is 100: 20-60 by weight.

Examples of the styrene block copolymer of the base polymer include styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, and styrene-ethylene-propylene-styrene copolymer which are hydrogenated products thereof. Coalescing, thermoplastic block copolymers such as styrene-ethylene-butylene-styrene and the like,
"Califlex TR1107" made by Shell Chemical Co.,
"Califlex TR1101", "Septon 2043" manufactured by Kuraray, "Clayton G165" manufactured by Shell Chemical
0 ”and the like are commercially available. Especially styrene-isoprene-
Styrene copolymers are preferred.

An α-methylstyrene polymer or a styrene-α-methylstyrene copolymer is used as a tackifying component, and preferably has a softening point (measured by the ring and ball method defined in JIS K2207) of 100 to 120 ° C. To use. For example, "Crystalex 3085", "Crystalex 3100", "Crystalex 1120", "Crystalex 514" manufactured by Rika Hercules Co., Ltd.
Commercially available products such as "0" are used.

Α-methylstyrene polymer or styrene-
The blending amount of the α-methylstyrene copolymer is 20 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the styrene block copolymer. If this blending ratio is too small, the cohesive force and the holding property are lowered, and if it is too large, the adhesive force and the initial tack are lowered.

As another tackifying component, an aliphatic petroleum resin, a rosin resin, a terpene resin or the like may be used together with the above-mentioned α-methylstyrene polymer or styrene-α-methylstyrene copolymer. Examples of the softening agent include naphthenic oils, aromatic oils, paraffinic oils and the like, and at least one of them is used.
In addition, an antiaging agent, a filler and the like may be added if necessary.

[0011]

EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Hot-melt type pressure-sensitive adhesives having various compositions shown in Table 1 were prepared by melting and stirring at 190 ° C. Next, using a hot melt coater, each pressure-sensitive adhesive in a melted state was applied to the kraft paper side of the kraft paper having a total thickness of 115 μm laminated on one side with polyethylene so as to have a thickness of 40 μm.

[0013]

[Table 1]

1) Califlex TR1107: Shell Chemical Co., Ltd. SIS block copolymer 2) Quinton R100: Nippon Zeon Co., Ltd. aliphatic petroleum resin 3) Crystallex 3100: Rika Hercules Co., Ltd. Α-Methylstyrene resin softening point 100 ° C. 4) Crystalrex 1120: Rika Hercules Co., Ltd. α-methylstyrene resin softening point 120 ° C. 5) Esclone G-90: Nippon Steel Chemical Co., Ltd. Kumaron indene resin 6) Shelf Rex 371N: Shell Chemical Co., Ltd., naphthenic oil 7) Irganox 1010: Ciba Geigy Co., Ltd.

The adhesive tapes of Examples 1 and 2 and Comparative Examples 1 to 3 thus obtained were tested for adhesive strength, ball tack value, cardboard holding power and odor sensory test according to the following test methods. Table 2 shows the results.

[0016]

[Table 2]

Adhesion According to JIS Z0237, various adhesive tapes having a width of 25 mm are adhered to a stainless steel panel in an atmosphere of 23 ° C., a 2 kg roll is pressure-bonded back and forth once at a speed of 300 mm / min, and a peeling angle after leaving for 20 minutes is set. The peeling force at 180 degrees and the peeling speed of 300 mm / min was measured.

Ball tack value J. According to the DOW method, various pressure-sensitive adhesive tapes with a length of 10 cm were attached on a stainless steel plate having an inclination angle of 30 degrees in an atmosphere of 23 ° C., and a diameter of 1 cm was measured from a position 10 cm from the upper end of the pressure-sensitive adhesive tape.
/ 32 ~ 1 inch 32 types of steel balls rolled at an initial speed of 0,
The number of the highest steel ball stopped on the adhesive tape was taken as the ball tack value. The larger the ball tack value, the higher the initial tack.

Cardboard holding power In the atmosphere of 23 ° C., various adhesive tapes having a width of 25 mm are attached to cardboard pieces by reciprocating once with an 800 g roller, and the tape is hung vertically so that the attachment area is 25 × 25 mm ^2. Then, a load of 3 kg was applied, and the time (minutes) until the tape peeled off was measured.

Various kinds of cardboard sealable adhesive tapes were prepared under the conditions of 65 ° C. and 80% relative humidity.
After accelerated aging for 4 hours, the adhesive tape was allowed to stand at room temperature for 24 hours, and these adhesive tapes were used for a cardboard sealability test.
As shown in Fig. 1, the flap of a commercially available cardboard box 1 (double carton) is folded and affixed to the upper and lower parts with an adhesive tape 2 having a width of 50 mm, and the edge portion 3 is 50 mm.
As a cardboard box was sealed. As shown in FIG. 2, the adhesive tape attaching portions 2 attached to the upper and lower two places in FIG. 1 are left sideways for 24 hours under the temperature condition of 40 ° C., and the adhesive tape is peeled off at the edge portion 3 at that time. It was confirmed whether or not. Five pieces of cardboard cases were evaluated for each of the tested adhesive tapes, and the case where there was no peeling of the edge portion was marked with ◯, and the case where peeling of the edge portion occurred even in one place was marked with x.

Odor sensory test A sensory test was conducted by 10 panelists arbitrarily selected. Each individual evaluated the degree of presence or absence of a specific odor and discomfort on a three-point scale. The case where there was no peculiar odor was marked with ◯, and the case where there was a peculiar odor was marked with x.

The pressure-sensitive adhesive tape using the coumarone-indene resin of Comparative Example 1 has excellent functions such as pressure-sensitive adhesive properties, cardboard-holding property and cardboard-sealing property, but has a peculiar odor. Further, the adhesive tape in which the blending amount of the α-methylstyrene polymer or the styrene-α-methylstyrene copolymer of Comparative Example 2 was 10 parts by weight with respect to 100 parts by weight of the styrene block copolymer, Inferior in cardboard retention and cardboard sealability. On the other hand, the adhesive tape containing 70 parts by weight of the compound of Comparative Example 3 has a high adhesive force, but the initial tack is significantly reduced.

[0023]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a hot-melt pressure-sensitive adhesive having the same adhesive properties as when using coumarone-indene resin and having no bad odor.

[Brief description of drawings]

FIG. 1 shows a cardboard box with various adhesive tapes attached.

FIG. 2 shows a state in which the cardboard box of FIG. 1 is turned sideways for a cardboard test.

[Explanation of symbols]

 1 Cardboard box 2 Various adhesive tapes 3 Edges of various adhesive tapes

Front page continuation (72) Inventor Hiroki Matsushita 2-3-3 Sekiguchi, Bunkyo-ku, Tokyo Nichiban Co., Ltd.

Claims (1)

[Claims] 1. A hot-melt pressure-sensitive adhesive composition containing a styrene-based block copolymer as a base polymer, wherein an α-methylstyrene polymer or styrene-α having a softening point of 100 to 120 ° C. is used as a tackifying component. -Methylstyrene copolymer is contained, and the compounding ratio of the styrene block copolymer and the α-methylstyrene polymer or the styrene-α-methylstyrene copolymer is 100: 20 by weight. 60 is a hot-melt type pressure-sensitive adhesive composition.