CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2017/015258, filed on Dec. 21, 2017, which claims priority to Korean Patent Application No. 10-2016-0176071 filed on Dec. 21, 2016, and Korean Patent Application No. 10-2017-0176446 filed on Dec. 20, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an adhesive composition having excellent kisstack.

BACKGROUND OF THE INVENTION

Adhesive labels commonly referred to as labels or label stickers are used in most industrial fields such as printing, chemistry, medicine, cosmetics, food industry, household electric appliances, automobiles, stationery, etc. as well as for product trademarks and advertisements. Generally, as a material of an adherend with which an adhesive label is attached, paper such as art paper, imitation paper, mirror paper, gold and silver paper, heat sensitive paper, kraft paper, fluorescent paper, sterilized paper, photographic paper, and the like, and films such as PET, PVC, PE, PP, PS, PI, and the like are used, and can usually be applied to the final product through regular printing on the surface.

For the adhesive used for such adhesive labels, its adhesive strength is determined depending on its application. For example, a permanent adhesive exhibits a strong adhesive strength of about 8 N/inch or more based on peel strength of 180 degrees using a standard adherend, but when paper is used as a surface paper, paper breakage occurs at the time of removal. On the other hand, a removable adhesive exhibits an adhesive strength of about 5 to 8 N/inch based on a peel strength of 180 degrees using a standard adherend, and if necessary, it shows adhesive strength at a level that allows removal, and it is mostly used for applications that temporarily adhere labels. That is, the adhesive can be classified into applications that are permanently or temporarily attached depending on the purpose.

Adhesive labels require high adhesion to be applied to containers having not only hard surfaces such as cement walls or steel plates, but also flexible surfaces such as plastic containers of cosmetics or pharmaceutical products, fancy goods, and the like. In general, there are an initial tack and shear resistance as items indicating the physical properties of the adhesive, and in addition, depending on the detailed classification of the product group and application, there are various test methods such as low temperature adhesion, adhesion strength after aging, dimensional stability, chemical resistance, mandrel hold, and the like. Usually, the permanent adhesive is a product that is excellent in both initial tack and shear resistance, and a limit exists for exhibiting the characteristics of the permanent adhesive only by the above physical properties.

In particular, an adhesive is generally prepared by copolymerizing an acrylic monomer, but it shows low kisstack properties compared to initial tack and peel strength, and thereby, a limit exists for increasing a kisstack only by the content of molecular weight modifier. Therefore, there is a need to study compositions showing excellent adhesion to various substrates requiring adhesion to not only flexible surfaces such as plastic containers but also to hard surfaces such as cement walls.

DETAILS OF THE INVENTION

Objects of the Invention

It is an object of the present invention to provide an adhesive composition not only having excellent initial tack but also exhibiting high kisstack characteristics.

It is another object of the present invention to provide an adhesive sheet using the above-described adhesive composition.

Means for Achieving the Object

According to one embodiment of the present invention, an adhesive composition including: acrylic emulsion resin particles; and 1 to 45 parts by weight of a water dispersible tackifier based on 100 parts by weight of the acrylic emulsion resin particles, wherein the acrylic emulsion resin particles are obtained by reaction between a (meth)acrylic acid ester monomer having a C1-C14 alkyl group, and 0.1 to 4.5 parts by weight of a monomer having a carboxyl group and/or a hydroxy group, or a mixture thereof, 0.5 to 12 parts by weight of a styrene-based monomer, 1 to 30 parts by weight of a vinyl acetate-based monomer, 0.01 to 2 parts by weight of a molecular weight modifier, and 0.01 to 2 parts by weight of a crosslinking agent, based on 100 parts by weight of the (meth)acrylic acid ester monomer, is provided.

As an example, the (meth)acrylic acid ester monomer having the C1-C14 alkyl group may be at least one selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, and lauryl (meth)acrylate.

The monomer having a carboxyl group may be at least one selected from the group consisting of maleic anhydride, fumaric acid, crotonic acid, itaconic acid, acrylic acid, and methacrylic acid.

The monomer having a hydroxy group may be at least one selected from the group consisting of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxylauryl (meth)acrylate, and hydroxypropyl glycol (meth)acrylate.

The styrene-based monomer may be at least one selected from the group consisting of styrene and α-methylstyrene.

The vinyl acetate-based monomer may be at least one selected from the group consisting of vinyl acetate, vinyl propionate, vinyl laurate, and vinyl pyrrolidone.

The water dispersible tackifier may be at least one selected from the group consisting of rosin-based, terpene-based, xylene-based, petroleum-based, and polybutene-based tackifiers.

In addition, the molecular weight modifier may be at least one selected from the group consisting of alcohol, ether, thioether, dithiocarbonate, natroxide, mercaptan, TEMPO, lauryl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol.

The crosslinking agent may be at least one selected from the group consisting of allyl methacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, hexanediol ethoxylate diacrylate, hexanediol propoxylate diacrylate, neopentyl glycol ethoxylate diacrylate, neopentyl glycol propoxylate diacrylate, trimethyl propane ethoxylate triacrylate, trimethyl propane propoxylate triacrylate, pentaerythritol ethoxylate triacrylate, pentaerythritol propoxylate triacrylate, vinyltrimethoxysilane, and divinylbenzene.

The kisstack, which is defined as a force measured when a sheet coated with the adhesive composition is instantaneously peeled off after being attached, may be about 6 N/inch or more.

Meanwhile, according to one embodiment of the present invention, an adhesive sheet, which is formed by coating the adhesive composition as described above onto one side or both sides of the sheet, is provided.

As an example, the adhesive sheet may an art paper.

Effects of the Invention

Since the adhesive composition according to the present invention not only has excellent initial tack but also exhibits kisstack characteristics of 6 N/inch or more, it can enhance an actual feeling adhesive strength that the end user perceives, and provide excellent adhesion to various substrates requiring adhesion, not only to flexible surfaces such as plastic containers such as a cosmetics or pharmaceutical products, and fancy article, but also to hard surfaces such as a cement wall or an iron plate.

