JPH0319877B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to a heat-sensitive self-adhesive tape suitable for binding various undried vegetables, fresh flowers, etc. (Technical background) Adhesive tape is used to bind unsensitized vegetables and fresh flowers. The adhesive tape used for this purpose is JP-A-Sho.
Those described in Japanese Patent Application Laid-open No. 54-96539, Japanese Utility Model Application Publication No. 54-107653, and Japanese Patent Application Laid-open No. 56-26968 are known. The adhesives applied to these known adhesive tapes are sticky at room temperature, so when using adhesive tapes, care must be taken to prevent the adhesive tape from adhering to items other than the intended object. was necessary. Therefore, there has been a long-awaited need for a binding tape coated with an adhesive that is not sticky at room temperature. (Prior Art) As conventional heat-sensitive adhesives, those mainly based on a copolymer of ethylene and vinyl acetate, and those mainly based on polyamide (homopolymer and copolymer) are known. These known heat-sensitive adhesives firmly bond two objects by melting a homopolymer or copolymer using heat, spreading it widely over the surfaces to be bonded, and then cooling it. be. When such a known heat-sensitive adhesive is used as an adhesive in a binding tape, the tape is used to bind a bundle of articles, and the adhesives of the tapes are bonded together (see attached Figure 3). for,
By applying heat to the parts to be joined, the adhesive flows and becomes integrated, and by cooling it, a strong bond is obtained. However, immediately after heating and binding, the adhesive is still in a fluid state, so the bonding strength is very weak. In this case, if force is applied in the direction of peeling immediately after binding, it will easily peel off. Furthermore, since a considerable amount of heat is required to fluidize the adhesive, it requires high temperatures and a long time, reducing the efficiency of the binding operation. (Object of the Invention) The object of the present invention is to eliminate the drawbacks of the above-mentioned known heat-sensitive adhesives. (Structure of the Invention) The present invention provides:
type (A in the formula has an average molecular weight of 2000 to 100000)
an independently selected non-elastomeric monovinyl aromatic hydrocarbon polymer block having a glass transition temperature of 25° C. or higher, the total content of Block A being from about 10 to about 50 percent by weight of the copolymer. , and B is an elastomeric conjugated diene polymer block having an average molecular weight of about 25,000 to about 1,000,000 and a glass transition temperature of about 10°C or less. ), natural rubber, polyisobutylene rubber with a molecular weight of 64,000 to 135,000, and a molecular weight of 100,000 to 100,000.
100 parts by weight of at least one elastomer selected from polyisoprene rubber having a molecular weight of 5,000,000 (preferably 840,000) and a high-cis molecular unit and butyl rubber having a molecular weight of 600,000 or more; good resin 10-30
80 to 250 parts by weight of a tackifier, which is a mixture of 90 to 70 parts by weight of C ₉ petroleum resin, and (c) 0 to 150 parts by weight of an additive, the adhesive composition is water resistant. This is a heat-sensitive self-adhesive tape that is coated on one side of a base material. Each element constituting the present invention will be explained in detail below. (Elastomer) The elastomer used in the present invention has a general structure of ABA type, such as a styrene-isoprene-styrene type block copolymer or a styrene-butadiene-styrene type block copolymer. Block copolymer, natural rubber, butyl rubber with a molecular weight of 600,000 or more, molecular weight of 64,000
Polyisobutylene rubber, molecular weight of ~135000
100,000 to 5,000,000 (preferably 840,000), and the molecular constituent unit is high cis, arbitrarily selected from polyisoprene rubbers. The A-B-A type block copolymer is
9932, and the styrene-isoprene-styrene type block copolymer was manufactured by Shell Chemical Co., Ltd.
Co., Ltd., as ``KRA-TON'' 1107 and ``KRA-TON'' There is. An example of a commercial product corresponding to butyl rubber having a molecular weight of 600,000 or more is Butyl #268 manufactured by Etsuso Standard Oil Company. Examples of polyisobutylene rubber are "VISTANEX" L-80, L-100, L-120 and L-140 manufactured by Esso Standard Oil Co., Ltd., and examples of polyisoprene rubber are "VISTANEX" manufactured by Kuraray Co., Ltd. There is "Kurapren" IR-10. Advantageously, the elastomer according to the invention contains at least 70 parts by weight of a styrene-isoprene-styrene block copolymer (abbreviated as SIS). This is because, although in this case, the heat-sensitive self-adhesive property will not decrease much, if the blending ratio of the elastomer other than SIS exceeds 30 parts by weight, the heat-sensitive self-adhesive property will be poor and it will become sticky at room temperature. be. (Tackifier) The tackifier used in the present invention contains 10 to 30% by weight of a resin that is compatible with the elastomer.
and 90 to 70% by weight of _C9 petroleum resin. The proportion of resin that is compatible with the elastomer is
If more than 30% by weight of tackifier is mixed with the elastomer, the resulting adhesive will be tacky at room temperature, so this tackifier is not suitable for the purpose of the invention. Furthermore, if a tackifier containing less than 10% by weight of a resin that is compatible with the elastomer is mixed with the elastomer, the resulting adhesive will not exhibit self-adhesion even at high temperatures. Not fit for purpose. Examples of resins having good compatibility with the elastomer include hydrogenated rosin, hydrogenated rosin ester, polyterpene, and _C5 petroleum resin. Each component of the tackifier used in the present invention preferably has a softening point of 100°C or higher. If a tackifier with a softening point of less than 100° C. is used, the thermosensitive self-adhesive property will be weak and the adhesive will become sticky at room temperature, which is not suitable for the purpose of the present invention. (Blending ratio of elastomer and tackifier) In the present invention, 80 to 250 parts by weight of the tackifier is blended to 100 parts by weight of the elastomer.
If the blending ratio of the tackifier exceeds 250 parts by weight,
The resulting adhesive becomes more fluid at temperatures higher than room temperature, and when this adhesive is applied and a bundle of other items is bound with tape, the self-adhesive strength immediately after binding is weakened. Not fit for purpose. Furthermore, if the blending ratio of the tackifier is less than the above range, the resulting adhesive will have tackiness at room temperature, so such a blending ratio is also not suitable for the purpose of the present invention. (Additives) The adhesive in the present invention can contain additives such as fillers. The blending ratio of the additive is at most 150 parts by weight per 100 parts by weight of the elastomer, and it is preferable to adjust the blending ratio of the additive depending on the softening point of the tackifier. The additive has the function of adjusting the cohesiveness and non-stickiness of the adhesive in the present invention. Substances that can be used as additives include calcium carbonate, zinc white (zinc oxide), titanium oxide, vegetable oil, and modified vegetable oil, and two or more of these can also be used in combination. If the amount of the additive exceeds 150 parts by weight per 100 parts by weight of the elastomer, the heat-sensitive self-adhesion will be poor. When using liquid additives, use elastomer to prevent excessive deterioration of adhesive cohesiveness.
It is desirable that the amount is within 10 parts by weight per 100 parts by weight. (Water-resistant base material) In the present invention, a film of polypropylene, polyethylene, unplasticized polyvinyl chloride, polyester, or the like can be used as the water-resistant base material. The thickness is preferably about 20 to 60 microns, and can be further increased or decreased depending on needs such as the workability of mechanical binding and prevention of damage to vegetables. In addition, the base material may be colored with a coloring agent or printed to the desired color, and the color of the base material may be changed depending on the type of vegetables, etc. to be tied, or the product name, production area name, collection date, etc. Displaying other information can greatly enhance the commercial value of the items to be bound. (Operations and Effects of the Invention) The heat-sensitive self-adhesive tape of the present invention has no tackiness or self-adhesion at room temperature, but becomes self-adhesive at temperatures higher than room temperature, for example, 50°C or higher.
In addition, the bonding strength at that temperature is large and it does not peel off easily. When binding a bundle of other articles using the heat-sensitive self-adhesive tape of the present invention, bind the articles using the heat-sensitive self-adhesive tape of the present invention as shown in FIG. If the coated surfaces are joined together and heated, a self-adhesion is instantly formed, and the resistance to peeling at that time is high, so various types of binding can be done efficiently, making it very convenient. However, in the example shown in FIG. 3, the contact surfaces between the vegetables and the tape are not heated, so they are not bonded, and the bundle of vegetables is tightened by the tension of the tape. Therefore, in the example shown in FIG. 3, when the tape 3 is cut, the vegetables can be loosened into pieces without being damaged at all. The heat-sensitive self-adhesive tape of the present invention can be applied to vegetables, fresh flowers, foods (dried fish, dried fish, etc.) at temperatures of approximately 50 to 200°C.
It can be used to wrap packaging boxes for ham, sausage, etc.), shoelaces, wire, and confectionery (caramel, chiyocolate, etc.). (Manufacturing method) The heat-sensitive self-adhesive tape of the present invention is produced by applying a solution of the adhesive of the present invention to one side of a water-resistant base material by a conventional method used when manufacturing ordinary pressure-sensitive adhesive sheets, and then It is manufactured by volatilizing the solvent inside, rolling it up onto a core, and then cutting it into a desired width. The thickness of the adhesive layer on the water-resistant substrate is suitably about 5 to 30 microns after drying, but is not limited to this range. The adhesive solution in the present invention can be produced as follows. First, the elastomer, tackifier, and optionally additives are kneaded using a Banbury mixer or a rubber kneading roll to form a uniform mixture. This mixture is dissolved in an organic solvent to form a solution having a solid content of about 10 to 40% by weight. Suitable organic solvent is hexane or a mixture of hexane and toluene. The adhesive solution thus obtained is used for applying onto a water-resistant substrate. When the additive is a liquid, the additive is not added when the elastomer and tackifier are kneaded, but the liquid additive is added when the mixture of the elastomer and tackifier is dissolved in an organic solvent. Good too. (Examples) In order to make the present invention easier to understand, Examples and Comparative Examples are shown below, but the present invention is not limited in any way by the following Examples. All numbers in the table below are parts by weight. Examples 1 and 2

[Table] Strength immediately after wearing

【table】

[Table] The accompanying drawings are explanatory diagrams showing embodiments and usage examples of the present invention. 1 and 2, an adhesive 2 is applied to one side of a base material 1 to constitute a heat-sensitive self-adhesive tape 3 of the present invention. In FIG. 3, vegetables 4 are shown bound together with heat-sensitive self-adhesive tape 3.
In this case, the sides coated with adhesive 2 are tied together so that they are in contact with the vegetables, and the ends 3a of the heat-sensitive self-adhesive tape are joined so that the sides coated with adhesive 2 face each other. .

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a schematic explanatory view showing the state of use. 1 is a base material, 2 is an adhesive composition layer, 3 is a heat-sensitive self-adhesive tape, and 4 is vegetables.

Claims (1)

[Scope of Claims] 1 (a) Styrene-isoprene-styrene type block copolymer or styrene-butadiene-
A-B like styrene type block copolymer
-A type (A in the formula has an average molecular weight of 2000 or less)
100,000 and a glass transition temperature of 25° C. or higher, an independently selected non-elastomeric monovinyl aromatic hydrocarbon polymer block;
The total content of B is about 10 to about 50 weight percent of the copolymer, and B has an average molecular weight of about
25,000 to about 1,000,000, and the glass transition temperature is about
It is an elastomeric conjugated diene polymer block that has a temperature of 10°C or less. ), a block copolymer with the general composition of natural rubber, with a molecular weight of 64,000
Polyisobutylene rubber, molecular weight of ~135000
At least one elastomer selected from polyisoprene rubber having a molecular weight of 100,000 to 5,000,000 (preferably 840,000) and a high-cis molecular unit and butyl rubber having a molecular weight of 600,000 or more.
100 parts by weight, and (b) 10 to 30 parts of a resin that is compatible with the above elastomer.
80 to 250 parts by weight of a tackifier, which is a mixture of 90 to 70 parts by weight of C ₉ petroleum resin, and (c) 0 to 150 parts by weight of an additive, the adhesive composition is water resistant. A heat-sensitive self-adhesive tape that is coated on one side of a base material.