JPH0433828B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to adhesives for fruit paper used for protecting fruits, etc., and particularly to special adhesives processed by impregnation with paraffin or silicone resin, etc. It relates to adhesives for processed paper.

[Prior Art and Problems to be Solved by the Invention] Fruit paper is generally used in the form of a bag, and this bag is placed over the fruit at the early stage of fruit growth to remove the fruit, such as pears, apples, grapes, etc. It is used to protect fruits from pests and diseases, and at the same time to promote the smooth growth of fruits by transmitting a moderate amount of ultraviolet rays.

When making a fruit bag, fruit paper is shaped into a bag, and the periphery of the bag other than the opening is pasted with adhesive. In this case, the specially treated water-repellent paper mentioned above is
Since it is difficult to uniformly apply water-based resin adhesives, conventionally solvent-based resin adhesives have had to be used. However, the use of solvent-based resin adhesives has the following drawbacks. In other words, (1) solvents dissolve specially processed impregnating ingredients, which adversely affects the transmission of ultraviolet rays, which is bad for fruit growth; and (2) safety, hygiene, and toxicity issues caused by solvents. (3) The adhesive force is too strong and the fruit is contaminated with the adhesive; (4) The cost is high.

In addition, as a conventionally known water-based emulsion type adhesive for water-repellent paper, for example, there is JP-A No. 53-91940, but this is an emulsion whose main component is an ethylene-vinyl acetate copolymer, and this emulsion alone cannot be used. The wax paper which is the object of the present invention cannot be laminated at all. Furthermore, a water-repellent cardboard adhesive containing vinyl acetate emulsion and acrylic-styrene copolymer latex as essential components is disclosed in JP-A-58-98239, but this adhesive requires heat treatment during lamination. and cannot be bonded at room temperature.

[Structure of the Invention] The present inventor has made efforts to develop an adhesive for fruit paper that improves the drawbacks of the above-mentioned solvent-based adhesives and has better adhesive properties and workability than known water-based emulsion-based adhesives. As a result of our investigation, we found that the following adhesives were superior. That is, the adhesive of the present invention is a fruit paper adhesive characterized by blending casein, rosin, an organic solvent, and a plasticizer with a mixture of natural rubber latex and styrene copolymer latex. be.

More specifically, the above natural rubber latex
10 to 30 parts by weight of styrenic copolymer latex
Preferably, the amount is 10 to 30 parts by weight, casein is 0.3 to 1 part by weight, rosin is 10 to 30 parts by weight, organic solvent is 10 to 30 parts by weight, and plasticizer is 3 to 10 parts by weight.

The natural rubber latex used in the adhesive of the present invention is necessary to provide adhesive and adhesion properties. The amount is between 10 and 30 parts by weight; outside this range, the adhesion and adhesion properties decrease.

Styrenic copolymer latex is necessary to prevent aging of natural rubber latex and improve adhesion. As this copolymerized latex,
Examples include styrene-butadiene copolymer and styrene-neoprene copolymer. Its usage is 10
-30 parts by weight, and if it is out of this range, the adhesiveness will decrease, which is not preferable.

The amount of casein used is 0.3 to 1 part by weight.

Rosin is necessary as a tackifier, and examples include Picolite A-115 (trade name).
The amount used is 10 to 30 parts by weight, and if it deviates from this range, the performance as a tackifier will deteriorate.

Examples of organic solvents include aromatic solvents such as toluene and xylene, such as n-hexane and n-
Examples include aliphatic solvents such as pentane and n-heptane, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate. Aromatic solvents are particularly preferred from the viewpoint of compatibility with the resin, workability, and the like. The amount of organic solvent used is 10
~30 parts by weight; outside this range, solubility with the resin and workability decrease.

Plasticizers are necessary to plasticize the resin and also improve adhesive properties. Examples of the plasticizer include phthalate esters such as diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and butylbenzine phthalate, and polyhydric alcohol plasticizers such as glycerin and diethylene glycol. The amount used is 3 to 10 parts by weight; if it is out of this range, the adhesive will not be sufficiently plasticized or the adhesive will deteriorate due to migration of the plasticizer.

The fruit paper adhesive of the present invention is suitably applied to fruit paper made of water-repellent paper.

[Effects of the Invention] The adhesive for fruit paper of the present invention improves the drawbacks of solvent-based adhesives, and although it is a water-based emulsion-type adhesive, it has excellent properties against water-repellent fruit paper. It exhibits adhesive properties, can be bonded at room temperature, and has excellent workability.

[Example] The adhesive of the present invention will be explained below with reference to Examples.

[Preparation of adhesive] Example 1 Mix the following components to obtain a concentration of 40.1% and a viscosity of 1000 cps.
(BL type viscometer, rotor No. 2, rotation speed 12), PH
= 10.1 adhesive was obtained. Proportions are parts by weight.

Natural rubber latex (concentration 50%) 20 parts Styrene-butadiene latex (concentration 50%) 20 Casein 0.5 Rosin 15 Xylene 15 Dibutyl phthalate 5 Ammonia water (25%) 0.1 Water 22.4 Total 100 parts Example 2 Mix the following ingredients. Concentration 40.3%, viscosity 950cps
(BL type viscometer, rotor No. 2, rotation speed 12), PH
= 10.0 adhesive was obtained. Proportions are parts by weight.

Natural rubber latex (concentration 50%) 10 parts Styrene-butadiene latex (concentration 50%) 30 Casein 0.5 Rosin 15 Xylene 15 Dibutyl phthalate 5 Ammonia water (25%) 0.1 Water 24.4 Total 100 parts Example 3 Mix the following ingredients. Concentration 40.3%, viscosity 1200cps
(BL type viscometer, rotor No. 2, rotation speed 12), PH
= 10.6 adhesive was obtained. Proportions are parts by weight.

Natural rubber latex (concentration 50%) 30 parts Styrene-butadiene latex (concentration 50%) 10 Casein 0.5 Rosin 15 Xylene 15 Dibutyl phthalate 5 Ammonia water (25%) 0.1 Water 24.4 Total 100 parts [Adhesion test and application to fruit] Effect Test] The adhesives obtained in Examples 1, 2, and 3 above were applied to the surface of wax paper for pear bags using an applicator.
The coating amount was 30 to 40 μm (dry). Immediately after coating, it was overlapped with the back side of wax paper and pressed with a rubber roller. This was left to dry at 20°C x 65% RH for 24 hours, and then a peel test was conducted. As a result, the wax paper adhered with the above adhesive was not peeled off by the adhesive layer and the wax paper was torn. Further, no dissolution of the resin content of the wax paper was observed, and no adverse effects on the fruit were observed at all.

As comparative examples, (1) ethylene-vinyl acetate copolymer emulsion (OM-4200, manufactured by Kuraray) and (2)
The same adhesion test and fruit impact test as above were conducted using a known solvent-based adhesive.

In the case of only the emulsion adhesive (1), it peeled off on the adhesive surface of the wax paper and could not be used. In the case of the solvent-based adhesive (2), the adhesive strength is strong enough to tear the wax paper as in the present invention, but the resin content on the surface of the wax paper dissolves and the light of this dissolved part The transmittance increased and stains appeared on the fruit surface. Furthermore, with solvent-based adhesives,
The resin content of the wax paper seeped into the inside of the wax paper bag along with the solvent and came into contact with the fruit surface, inhibiting fruit growth in that area.

Claims (1)

[Claims] 1. A mixture of natural rubber latex and styrene copolymer latex containing casein, rosin,
A fruit paper adhesive characterized by containing an organic solvent and a plasticizer. 2 10 to 30 parts by weight of the above natural rubber latex,
Styrenic polymer latex is 10 to 30 parts by weight, casein is 0.3 to 1 part by weight, rosin is 10 to 30 parts by weight,
The adhesive for fruit paper according to claim 1, characterized in that the organic solvent is 10 to 30 parts by weight and the plasticizer is 3 to 10 parts by weight.