JPS61246239A - Self-adhesive composition - Google Patents

Abstract

PURPOSE:A harmless self-adhesive composition having water solubility, edibility, spantaneous degradability, etc., and being useful for various self-adhesives such as food packaging adhesive tapes and medical sticking plasters, obtained by adding a small amount of a self-adhesive substance and a plasticizing substance to pullulan. CONSTITUTION:A self-adhesive substance and a plasticizing substance are added to pullulan. It is preferable that at least one member selected from among a cohesive force improver, a viscosity controlling substance and an extender is added thereto in addition to said two substances. When only edible materials are used as the additives, the obtained composition is an edible self-adhesive, and when natural substances or nonpolluting substances are used as the additives, the obtained composition is a nonpolluting self-adhesive. When water- soluble substances are used as the additives, the obtained composition is a water-soluble self-adhesive. Examples of the self-adhesive substances and the plasticizing substances include glycerin and sorbitan fatty acid esters. Examples of the extender/viscosity controlling substances include lactone and maltose. Examples of the cohesive force improvers include gelatin and gum arabic.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to adhesive compositions. More specifically, the present invention relates to an adhesive composition containing the natural polysaccharide pullulan as a main ingredient.

For example, there are many adhesive compositions constituting adhesives, but almost none of these adhesives are non-polluting, water-soluble, and edible.

That is, as a water-soluble adhesive, for example, JP-A-4T7-! ♂
As seen in Publication No. 3♂ and Japanese Patent Application Laid-open No. 4T7-39/4TO, etc., it is made from synthetic substances such as acrylic acid alkyl esters and maleic acid-methyl vinyl ether copolymer. Although it is water soluble,
Properties such as their degradability and the toxicity of the decomposition products have not been clarified. Even if the above-mentioned properties were clarified, it would be practically impossible to recover the adhesive and treat it as required due to the nature of the adhesive. Water-soluble adhesives have the advantage of being easily removed by washing with water, and are desired to be harmless. In addition, an edible adhesive based on gelatin and collagen was proposed (Jitsukai Shojθ-707♂3
However, no technical solution as an adhesive has been made.

Conventionally, natural proteins such as gelatin and collagen, starch, natural products such as sodium alginate, methylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose, or derivatives thereof, have been used in a wide range of applications as water-soluble thickeners and water-soluble adhesives. Since all of these substances are water-soluble polymer compounds, they are used as the above-mentioned pastes and adhesives, but cannot be used as raw materials for adhesives. When a certain amount of an edible, harmless plasticizer, such as glycerin, is mixed and dissolved in these polymeric compounds, a flexible film is obtained, but no tackiness is developed. Furthermore, when a harmless plasticizing substance such as glycerin is added to this, tackiness develops, but it also causes the surface to become sticky, and when used as an adhesive for pasting, etc., the adhesive may appear on the adhered surface. As a result, it is not possible to obtain a pressure-sensitive adhesive that has the properties necessary for a pressure-sensitive adhesive, that is, a well-balanced balance of tack, cohesive force, and adhesive force. Appropriate adhesion and cohesive force cannot be obtained without polymeric compounds, but natural polymeric substances such as those mentioned above or their derivatives require a large amount of plasticizing substances as mentioned above to develop adhesiveness. etc., so it cannot be an adhesive with well-balanced tack, cohesive force, and adhesive force. In other words, the above natural polymer compounds or their derivatives can be used as rewetting adhesives or glues, but they cannot be used as practical adhesives with a well-balanced tack, cohesive force, and adhesive force. It was generally thought that it was unobtainable.

The present inventors have repeatedly conducted various studies on adhesive compositions that cause little or no pollution, and have found that pullulan, which belongs to natural polysaccharides, has a small amount of plasticity compared to the above-mentioned natural polymer compounds or their derivatives. It has been found that tackiness can be developed by adding a tackifying substance or a tackifying substance.

The present invention is an adhesive composition comprising pullulan mainly containing a tackifying substance and a plasticizing substance, or further containing a cohesive force improver, (or) a viscosity adjusting substance, (or) an extender, etc. It is water-soluble, edible, and naturally degradable, so it is harmless and can be used for various purposes.

The pullulan used in the present invention is a viscous polysaccharide in which maltotriose, which is a trimer of glucose, is repeatedly bonded through α- and O-bonds.
It has a high molecular weight of 10,000,000,000, and can develop the required tackiness by adding a tackifier or plasticizer that provides tackiness at room temperature in a small amount compared to other natural polymer compounds. In addition, the above-mentioned tackifying substances mixed and dissolved are extremely elastic, and even if other water-soluble substances, pigments, fillers, etc. are added to them, the elasticity will not be significantly impaired. do not have. This property means that, for example, when changing the properties of the adhesive, the range of change is wide, and it can be said that pullulan plays the role of an elastomer in the adhesive composition. Therefore, by mixing and dispersing or mixing and dissolving various substances into this pullulan-containing system, adhesive compositions having various properties can be obtained.

In this case, if only edible materials are used as the contaminant, the adhesive composition will be an edible adhesive, and even if it is not edible, if a natural substance or a substance that does not cause pollution is used, it will become a non-polluting adhesive. It is possible to obtain an adhesive composition having the following properties. Since pullulan is a substance that dissolves quickly in water, if a water-soluble contaminant is used, the adhesive composition becomes a water-soluble adhesive or the like. The above-mentioned edibility refers to physical properties that do not pose a problem when eaten by humans or other animals.

Tackifiers and plasticizers that impart stickiness to pullulan include food additives such as glycerin, propylene glycol, lactic acid, sodium lactate, sucrose fatty acid ester, sorbitan fatty acid ester, and glycerin fatty acid ester. In addition to the above-mentioned tackifying substances and plasticizing substances, monomers such as grape sugar, lactose, maltose, coupling sugar, D-sorbitol, etc., which serve as bulking agents and, in some cases, viscosity (plasticity) adjusting substances, may be used as necessary. Sugars, trisaccharides, kaolin, clay calcium carbonate, inorganic substances such as silicic anhydride, and small amounts of cohesive force improvers to increase the cohesive force of the resulting adhesive, such as gelatin, gum arabic,
Guar gum, tragacanth gum, starch, tamarind seeds,
Natural substances or derivatives thereof such as sodium alginate, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and carboxytylated cellulose, inorganic substances such as silicic anhydride, and synthetic compounds such as sodium acrylate are appropriately added.

Since the present invention is configured as described above, water-soluble and (
or), is edible and/or naturally degradable, is harmless, and can be used for various purposes. For example, edible items include adhesive tapes and adhesives for food packaging, edible vegetables and grasses,
Adhesives such as binding tapes for straw, feed, etc. do not cause any harm even if they remain attached to food or feed; if they are water-soluble, they can be easily removed by washing with water, and they do not contaminate wastewater, etc. do not have. Furthermore, when used as an adhesive component in medical bandages, patches, etc., it does not cause skin disorders such as rashes. In addition, the above-mentioned composition is used as an adhesive component, with or without the addition of appropriate chemicals, as a repellent, trapping agent, attractant for pests and pests, as a binder for finely powdered foods, as a non-slip treatment for papers, etc. It can be used as a base material for drugs, sustained release drugs or fragrances, base materials for edible inks, and other uses.

Next, examples will be described. Each of the compositions listed in the examples can be used as appropriate for the various uses mentioned above.

Example/ Pullulan PF CoO (Hayashibara Shoji ■Product name) sr
glycerin 3f lactic acid
32 water
72 Film thickness of the above formulation! The adhesive properties of the product applied to θ micron cellophane to a dry film thickness of 30 microns and dried were as follows.

Pole tuck (J, Dow method)/! Adhesive strength (J Is) /IOf//2m
Width retention force (substrate Nigarasu) 29 minutes/72 ■Width
Falling at 20"//1'4 Example 2 Pullulan PF, 2θ!? Glycerin
3f Reduced maltose IO? Water 7f The above composition was treated in the same manner as in Examples to obtain the following adhesive properties.

Pole tack / evening adhesive force 220 t / / 2 m width holding force j3 minutes // 2 ■ Width x λθ ■ //
Dropped in 9 Example 3 Pullulan PF20 i?
glycerin 3f maltose
iot carboquine methylcellulose 0.21 water
1♂ with the above composition, 2! The pressure-sensitive adhesive layer was coated on a micron polyester film to a thickness of 70 microns and dried, and the adhesive properties were as follows.

Pole tack /θ Adhesive force / 70 f / / 2 +
m width retention force (substrate Nigarasu): 7 m deviation in 2 hours
//, 2m5X 20 mm / / Kg Comparative Examples C, M, C-F 8 B (Carboquine methyl cellulose, Daiichi Kogyo Seiyaku ■ trade name) sr glycerin θ to water 100f.

The adhesive properties of the above composition obtained in the same manner as in Example 3 are as follows.

Pole tuck! Below adhesive strength 3θt//2IIIl1
Holding power below width: about 7 seconds // 2rtas width x 20 IIm // Kg There was significant stickiness and residual adhesive.

Example Gupurulan PF20 j? Sodium lactate 3f Reduced maltose 109 Water l♂? C, M,, C/
Chi aqueous solution /! ? The adhesive properties of the above composition obtained in the same manner as in Example 3 were as follows.

Pole tack Otsu holding power 37 minutes//Ko Shin x Ko θ■//K
y Adhesive strength /4t09//2m width example! Pullulan PF20! ? Propylene glycol 31 Maltose 2t C, M, C/thi aqueous solution 7f water
109 The adhesive properties obtained in the same manner as in Example 3 were as follows: Pole tack? Holding power 10 minutes / / 2 m
2θvm/ / Kg

Claims (1)

[Scope of Claims] 1. An adhesive composition containing pullulan and a tackifying substance and a plasticizing substance. 2. An adhesive composition containing pullulan and one or more selected from a tackifier, a plasticizer, a cohesive force improver, a viscosity adjusting substance, and a filler. 3. Tackifying substance or plasticizing substance, viscosity adjusting substance,
The adhesive composition according to claim 1 or 2, wherein the cohesive force improver and filler are edible. 4. The adhesive composition according to claims 1 to 3, wherein the tackifying substance, plasticizing substance, and viscosity adjusting substance are water-soluble. 5. The adhesive composition according to claims 1 to 4, wherein the tackifying substance, the plasticizing substance, the cohesive force improver, and the viscosity adjusting substance are naturally degradable.