JPH0452311B2 - - 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 relates to adhesives for fruit paper used for protecting fruits, etc., and in particular, adhesives that are specially processed by impregnation with paraffin or silicone resin, etc. It relates to adhesives for 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 hold the fruit, such as pears, apples, grapes, etc. It is used to protect against 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 a vinyl acetate emulsion and an acrylic-styrene copolymer latex as essential components is disclosed in JP-A-58-98239, but this adhesive requires heat treatment during lamination. It is not possible to bond 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 discovered that the following adhesives are superior. That is, the adhesive of the present invention is an adhesive that is applied to water-repellent fruit paper, and has a boiling point of 50% based on 100 parts by weight of the resin content of a vinyl acetate emulsion that does not contain ethylene as a constituent monomer. ~150℃ organic solvent 30~200
This is an adhesive for fruit paper, characterized in that it contains 3 to 30 parts by weight of a plasticizer, and 0.1 to 10 parts by weight of a nonionic or anionic surfactant.

Examples of the aqueous vinyl acetate emulsion used in the adhesive of the present invention include polyvinyl acetate emulsion and vinyl acetate copolymer emulsion. Vinyl acetate copolymers include vinyl acetate, acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, polymerizable unsaturated acids,
For example, acrylic acid, methacrylic acid, maleic acid,
There are copolymers in which 1 to 30% by weight of fumaric acid, crotonic acid, dioctyl maleate, dimethyl maleate, acrylamide, hydroxyethyl acrylate, etc. are copolymerized. Particularly preferred is polyvinyl acetate emulsion.

Examples of the polymerization catalyst include known peroxides known to act as free radical catalysts, such as persulfates containing ammonium, sodium, potassium, or potassium, hydrogen peroxide, perborates, butyronitrile peroxide, etc. be able to.

The organic solvent must have a boiling point of 50 to 150°C, such as hexane, acetone,
You can choose from a wide range of organic solvents such as xylene, toluene, etc. The amount used is 30 to 200 parts by weight, preferably 100 to 180 parts by weight, per 100 parts by weight of the resin content of the aqueous vinyl acetate emulsion. This amount
If it is less than 30 parts by weight, adhesiveness will decrease, and if it exceeds 200 parts by weight, the viscosity will be too high, reducing workability and having an adverse effect on the fruit.

Examples of the plasticizer include phthalate esters such as diethyl phthalate, dibutyl phthalate, dioctyl phthalate, butylbenzyl phthalate, citric acid esters, and glycerin. The amount of plasticizer used is 100% of the resin content of vinyl acetate emulsion.
It is preferably 3 to 30 parts by weight. If the amount of plasticizer is less than 3 parts by weight, film forming properties will be poor, and 30
If the amount exceeds 1 part by weight, it is not preferable because the transfer to paper becomes significant and the adhesiveness decreases.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, sorbitan fatty acid ester, polyoxyethylene amyl ester, aliphatic monoglyceride, and the like. In addition, as anionic surfactants, aliphatic salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, naphthalene sulfonate formalin condensates, dialkyl sulfosuccinates, polyoxy Examples include ethylene alkyl sulfate. These surfactants can be used alone or in combination of two or more, and the amount used is based on 100 parts by weight of the resin content of the vinyl acetate aqueous emulsion.
The amount is preferably 0.1 to 10 parts by weight.

[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.

Example 1 [Preparation of adhesive] The following components were mixed to give a concentration of 24.2% and a viscosity of 2000 cps.
(BL type viscometer, rotor No. 3, rotation speed 30), PH=
5.5 adhesive was prepared. Proportions are parts by weight.

Polyvinyl acetate emulsion (concentration 50%) 36 parts Xylene 15 parts N-hexane 15 parts Dibutyl phthalate 5 parts Polyoxyethylene nonylphenyl ether (emulsifier) 0.5 parts Polyoxyethylene alkyl allyl ether sulfate (emulsifier) 0.5 parts Water 25 parts [Adhesiveness test and effect test on fruit] The adhesive obtained above was applied to the surface of wax paper for pear bags using an applicator. Application amount is 30~
It was 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 bonded 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 a comparative example, (1) ethylene-vinyl acetate copolymer emulsion (OM-4200, manufactured by Kuraray Co., Ltd.);
(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 on the surface of the wax paper dissolves and
The light transmittance of this dissolved portion increased, causing spots to appear on the fruit surface. Furthermore, when using a solvent-based adhesive, 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 surface of the fruit, inhibiting the growth of the fruit in that area.

Claims (1)

[Claims] 1. An adhesive applied to water-repellent fruit paper, containing 30 parts by weight of an organic solvent with a boiling point of 50 to 150°C per 100 parts by weight of the resin content of a vinyl acetate aqueous emulsion that does not contain ethylene as a constituent monomer. ~200
An adhesive for fruit paper, characterized in that it contains 3 to 30 parts by weight of a plasticizer, and 0.1 to 10 parts by weight of a nonionic or anionic surfactant.