JPH0345679A - Adhesive for label and glass base - Google Patents

Abstract

PURPOSE:To obtain an adhesive for label with high initial adhesive force, good cold water resistance and excellent alkali cleansing characteristics by incorporating a PVA resin with a high degree of saponification and a substance which is water-insoluble and alkali-soluble and/or alkali-swelling as active ingredients. CONSTITUTION:An adhesive for label is obtd. by incorporating a PVA resin with a degree of saponification of 85-100mol% and a substance which is water- insoluble and alkali-soluble and/or alkali-swelling (e.g. alpha-olefin-maleic anhydride copolymer) as active ingredients. The obtd. adhesive exhibits high initial adhesive force and an extremely good balance between cold water resistance and alkali cleansing characteristics. Therefore, as the cold water resistance is good when a beverage-filled glass bottle on which a label has been stuck with this adhesive is cooled and the peeling of the label with an alkali is easy to perform after recovery of the bottle, it is useful especially for an adhesive for label for a glass bottle for beverage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a label adhesive and a glass substrate to which a label coated with the adhesive is attached. More specifically, the present invention relates to an adhesive for bottle labels that has good water resistance in cold water and excellent alkaline washability.

(Prior Art) Label adhesives used for bottles, especially bottles for filling beverages such as beer, have high adhesive strength and good water resistance when immersed in cold water (hereinafter abbreviated as cold water resistance). In addition, it is necessary to have excellent washability with alkaline water when washing bottles (hereinafter abbreviated as alkaline washability). Conventionally, casein-based adhesives, starch-based adhesives, polyvinyl alcohol-based adhesives, and the like are known as such adhesives for labels. However, since casein-based adhesives are natural products, they have problems in that their quality is unstable or they are susceptible to decay, and furthermore, they have insufficient cold water resistance.

In addition, starch-based adhesives are formulated using starch in combination with urea and styrene-maleic anhydride copolymer (
U.S. Pat. No. 3,857,803) is known, but this formulation has the drawbacks of poor water resistance and poor alkaline cleaning properties.

Furthermore, polyvinyl alcohol (hereinafter abbreviated as PVA) is used.

) type adhesives include (1) conventional PVA mixed with starch, inorganic thickener, etc. (German Patent Application Publication No. 2,364,438), (i) PVA, thickener, urea, and synthetic resin emulsion. (Japanese Unexamined Patent Publication No. 56-16572) is known.

However, all of these had drawbacks of insufficient water resistance and poor alkaline cleaning properties.

(Problems to be Solved by the Invention) The object of the present invention is to provide a label adhesive that satisfies various performance requirements as a label adhesive used for bottle labels, has good adhesive properties, and is also water resistant and alkaline washable. An object of the present invention is to provide an excellent novel adhesive for labels and a glass substrate to which a label coated with the adhesive is attached.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors found that a PVA-based resin (A) having a saponification degree of 85 to 100 mol%
The present inventors have surprisingly found that the above object can be achieved by using an adhesive composition which is water-insoluble and has an alkali-soluble and/or alkali-swellable substance (B) as an essential component, and has completed the present invention. reached. The present invention will be explained in detail below.

PVA-based trees 1 (A) used in the present invention include ordinary PVA, silicon-containing modified PVA, and epoxy-modified PVA.
VA, acetoacetylated PVA1 carboxyl group-modified P
VA, sulfonic acid group-modified PVA.

Modified PVA copolymerized with phosphate group-modified PVA, amino group-modified PVA, ammonium group-modified PVA, amide-modified PVA, meth (meth)acrylamide, α-olefin, etc.
etc. can be used. It is essential that the saponification degree of these is 85 to 100 mol%.

Preferably, the degree of saponification is 9G-100 mol%. More preferably, the degree of saponification is 96 to 100 mol%. If the degree of saponification is lower than 85 mol%, water solubility decreases, and an adhesive cannot be prepared, or even if it can be prepared, cold water resistance is insufficient. That is, in order to meet the requirements of cold water resistance and ease of preparation of the adhesive, the degree of saponification is 85 to 1. Q
0 mol% is an essential condition. Also, these PVA trees It
There is no particular limit to the degree of polymerization of (A), but it is usually 10
The number is selected from the range of 0 to 5,000, and 300 to 3,000 is more preferable in terms of adhesiveness, workability, quality stability, etc.

Water-insoluble and alkali-soluble and/or alkali-swellable substance (B) used in the present invention and which characterizes the present invention (hereinafter sometimes abbreviated as substance (B)).
They must be present in particulate form in an aqueous adhesive solution or dispersion, and have the properties of being water insoluble and having excellent alkali solubility or alkali swelling properties. Furthermore, it is preferable to dissolve or swell in a short time with an alkali. Substance (B) is not particularly limited in shape as long as it is insoluble in water and can exist in particulate form in an aqueous adhesive solution or dispersion as long as it does not impair its function as an adhesive, but powder, emulsion, suspension dispersion, etc. An aqueous dispersion such as Among them, powder is more preferable.

There is no particular restriction on the particle size, but in the case of powder, the average particle size is preferably 100 μm or less.

Examples of the substance (B) used in the present invention include copolymers of carboxyl group-containing olefinic monomers, acid-type superabsorbent resins, casein, cellulose compounds, starch, aluminum, and silica.

Copolymers of carboxyl group-containing olefinic monomers include carboxyl group-containing monomers (hereinafter abbreviated as monomer (1)) such as (meth)acrylic acid, crotonic acid, maleic anhydride, and itaconic acid. ) and α-olefin,
Examples include copolymers with vinyl esters, vinyl ethers, (meth)acrylic esters, vinyl chloride, acrylonitrile, etc. (hereinafter sometimes abbreviated as monomer (2)). As an α-olefin, α having 2 to 20 carbon atoms is used.
- olefins, preferably α having 2 to 8 carbon atoms;
-olefins are used, specifically ethylene, propylene, butene-11butene-2, isobutyne, 2-methyl-butene-1,3-methyl-butene-11pentene-
Examples include 1,2-methyl-pentene-1,3-methyl-pentene-summer, 4-methyl-pentene-11 octene-11 diisobutylene, styrene, α-methylstyrene, etc. Ill or 21 or more of these are used. It will be done. Vinyl esters include vinyl acetate, vinyl propionate,
Examples include t-butyl vinyl ester and vinyl versatate. Examples of the vinyl ether include ethyl vinyl ether, butyl vinyl ether, octyl vinyl ether, lauryl vinyl ether, and stearyl vinyl ether.

Examples of (meth)acrylic acid esters include methyl, ethyl, butyl, 2-ethylhexyl, and lauryl esters of (meth)acrylic acid. These can be used alone or as a mixture of 2N or more. There is no particular restriction on the copolymerization ratio of these monomers (1) and monomers (2) as long as they are water-insoluble and have alkali solubility and/or swelling property. ) is maleic anhydride, the monomer (2
)/monomer (1) molar ratio of 0.5/1 to 5/l, more preferably 1/1. Furthermore, when the carboxyl group-containing monomer (1) is (meth)acrylic acid, crotonic acid, or itaconic acid, the monomer (2)/monomer ( The molar ratio of 1) is preferably 5/1 to 50/l.

Among the above-mentioned copolymers, copolymers of carboxyl group-containing monomers and vinyl esters and α-
Copolymers of olefin and maleic anhydride, particularly copolymers of isobutyne and maleic anhydride, and styrene and maleic anhydride, are preferably used from the viewpoint of water insolubility and alkali solubility and/or alkali swelling property.

As the above-mentioned maleic anhydride, maleic acid, a salt of maleic acid, or a maleic acid monoester may be mixed and used in a small amount of 10% or less based on maleic anhydride.

It is suitable to use the above-mentioned copolymer as a fine powder with an average particle diameter of 100 μm or less.

Furthermore, the acid-type superabsorbent resin referred to herein can be obtained by subjecting the superabsorbent resin to a dealkalization treatment (for example, neutralization treatment with an acid). This includes resin powder h< which is insoluble in water and swells in alkali. However, the super absorbent resins mentioned here include cross-linked polyacrylates, cross-linked products of saponified vinyl acetate-methyl acrylate copolymer, cross-linked products of saponified vinyl acetate-monomethyl maleate copolymer, and isobutylene-anhydride. Crosslinked product of saponified maleic acid copolymer, starch-acrylic acid graft polymer, polysaccharide-
Examples include acrylic acid graft polymer, hydrolyzate of starch-acrylonitrile graft copolymer, crosslinked carboxymethyl cellulose, and crosslinked polyethylene oxide. Among these, it is preferable to use a crosslinked product of a saponified isobutylene-maleic anhydride copolymer obtained by dealkalization treatment and used in the form of a fine powder. Examples of casein include acid casein, rennet casein, rough casein, and modified compounds thereof.
It is preferable to use these in the form of fine powder.

In addition, the cellulose-based compounds mentioned here include acid-type carboxymethylcellulose (hereinafter abbreviated as acid-type CMC), metal salts of carboxylic acid with a relatively low degree of substitution (for example, QSMg, Ca), and carboxylmethylcellulose.
, with a degree of substitution of 10 to 30 mol%, such as Na%),
Examples include hydroxypropyl methylcellulose phthalate, hydroxybrobyl methylcellulose acetate sacnate, carboxymethylethylcellulose, cellulose acetate phthalate, and methacrylic acid copolymers. Among them, acid type CMC is preferred. It is preferable to use these in fine powder form.

In addition, the starches mentioned here include natural starches such as sweet potato starch, potato starch, corn starch, wheat starch, tapioca starch, rice starch, decomposition products of natural starches, alpha starch, starch esters, starch ethers, etc. Examples include derivatives of starch, processed starches that have undergone physical treatments such as radiation, neutron beam, high frequency treatment, and moist heat treatment.

Among these, natural starch is preferred, and it is suitable to use it in fine powder form.

These substances (B) are insoluble in water, but have the property of dissolving or swelling in a short time by reacting with an aqueous alkali solution. Examples of alkali include hydroxides such as sodium, potassium, and lithium, and carbonic acid. Can you name salts, ammonia, organic amines, inorganic amines, hydroxides and carbonates of calcium, magnesium, aluminum, zinc, etc. - For example, in the beer industry, they are inexpensive and industrially available as alkali cleaning fluids. Sodium hydroxide, which is easy to clean, is used, and alkaline cleaning is very practical and useful if it is effective in an aqueous sodium hydroxide solution.

Among the above-mentioned substances (8), α-oI-nofin-maleic anhydride copolymer, crotonic acid-modified polyvinyl acetate, casein, and aluminum are preferable, and isobutylene-maleic anhydride is more preferable in terms of water resistance and alkali washability. Particularly preferred are acid copolymers and styrene-maleic anhydride copolymers.These copolymers are preferably used in fine powder form.

There is no particular limit to the blending weight ratio (solid content ratio) of PVA-based 1m fat (contains) and substance CB), but from the viewpoint of adhesiveness and alkaline cleaning effects, PVA-based resin (A) 100%! Preferably, 2 to 500 parts by weight of substance (B) per part;
B) 20 to 300 parts by weight is more preferable. If the amount of substance (8) is 2 parts by weight or less, its contribution to alkaline cleaning properties is small. On the other hand, if the substance (B) is 500 parts by weight or more, the water-resistant adhesive strength decreases and the cold water resistance deteriorates.

In addition, the PVA resin (A) and the water-insoluble and alkali-soluble and/or alkali-swellable substance (B) used in the present invention are essential components of the adhesive, and they are essential for improving initial tack, water resistance, and fluidity. Fillers can be used in combination with the adhesive for the purpose of improving the adhesive properties. Fillers include clay talc, limestone, calcium carbonate, aluminum hydroxide, aluminum oxide, gypsum, titanium oxide,
Diatomaceous earth, valarim sulfate, calcium sulfate, mica,
I! selected from inorganic substances such as glass, plastic pigments, benzoguanamine resin, acrylic resin, styrene 1 as fat, organic substances such as urea formalylene resin, etc. Alternatively, a mixture of two or more types can be used. Among these, clay is preferred in terms of water resistance, fluidity, etc.

PVA-based tree [1 (A) and substance (B) t, - blending weight ratio of filler (C) when used together (
Solid content ratio) is 2 to 500 parts by weight, preferably 20 parts by weight of filler (C) to 100 parts by weight of PVA resin (^).
~400 weight! parts, more preferably 50 to 300 parts by weight. If the blending ratio of filler (C) is greater than 500 parts by weight, this is not preferable as it leads to deterioration in the fluidity of the adhesive and a decrease in adhesive strength. In addition, water-based emulsions, thickeners, etc. may be added as needed to improve initial adhesion, adjust viscosity, improve fluidity, etc.
It can also be used in combination for purposes such as preventing stringiness.

As other additives, various antifoaming nets, fat preservatives, antifungal agents, viscosity stabilizers, coloring pigments, deodorants, fragrances, etc. can also be added as required. In order to improve adhesive strength, water-soluble boron compounds such as boric acid, borax, and boric acid esters of polyhydric alcohols such as glycerin and ethylene glycol can be added. However, if the amount added is large, it will adversely affect high-speed coating properties.

Although the adhesive of the present invention is water-based, alcohols such as methanol, ethylene glycol, and glycerin, and organic solvents such as cellosolves may be added in order to impart flexibility to the adhesive phase.

As an example of the method for preparing the adhesive of the present invention, a pre-mixed mixture of 1M PVA-based tree (A) and substance (B), as well as fillers and other additives as necessary, is poured into water while stirring. Alternatively, add the additives, filler material (B), and PVA resin (A) into water while stirring to create a slurry solution, and then add the slurry to the water in a jet extractor or preparation tank. It can be prepared by heating and melting it by any heating method, such as a superheating method in which steam is directly blown into the liquid, or an indirect heating method using a noyacket, and then cooling it, or it can be prepared by cooling it, or if it is a substance other than substance (B) in the above-mentioned composition. is prepared by heating and melting as described above and adding substance CB) after cooling. The prepared adhesive of the invention is used for labeling purposes, and is especially suitable for glass beverage bottles, especially beer bottles.

The viscosity of the adhesive varies depending on the application, but when high-speed coating is intended, the viscosity at the lamination temperature is preferably a B-type viscosity of s, ooo to 10,000 cps, and more preferably 10,000 cps.
A more suitable viscosity range is from 10,000 to 50,000 asp.

Labels to which the adhesive of the present invention can be used include paper, processed paper (for example, paper treated with aluminum vapor deposition, aluminum lamination, varnishing, resin processing, etc.), papers such as synthetic paper, films made of organic and inorganic compounds, and metals. This applies to labels made from films of compounds, etc. The other adherend may be of any material, including inorganic and organic materials such as glass, metal, and plastic, but glass bottles for beverages are particularly preferred.

(Example) The present invention will be specifically explained below with reference to Examples 1, but the present invention is not limited to these in any way. means "parts by weight" or "% by weight".

Example 1 Melt with stirrer equipped with thermometer 1111)! 100 parts of PVA resin (PV A-117 manufactured by Kuraray, degree of saponification 98.5 mol%, degree of polymerization 17-ffo) and crotonic acid-modified polyvinyl acetate fine powder (ASRCL manufactured by Denki Kagaku Kogyo).
-09. When 50 parts of powder (alkali-soluble type) was added to 500 parts of water and heated at 95° C. for 1 hour while stirring, only PVA-117 was dissolved. This was cooled to obtain adhesive base 1. The resulting adhesive was dissolved in PVA-117 aqueous solution.
This mixture of crotonic acid-modified polyvinyl acetate was dispersed in a fine powder form and had good fluidity. Table 1 summarizes the composition and properties of the adhesive, and the evaluation results (initial adhesive strength, normal adhesive strength, cold water resistance, alkaline cleanability and odor were evaluated by the following methods) are shown in Table 2.
Table (shown here)

(Initial Adhesion Strength) A glass plate (LOciX foci, thickness 2 mm) that has been washed and dried in advance is preheated to 40° C., and the adhesive agent (1) is applied to the label paper using a bar coater. The solid content of coating 1 was expressed as log/l''. This label paper was glued to the glass plate and immediately pressed lightly with a rubber roller to create a test piece. After 30 seconds, (manufactured D CS-100 type) (1 piece 500
The initial adhesive strength was measured by peeling at 180° at a tensile speed of +m/min. The results are shown with the following symbols.

◎There is no interfacial peeling between the Nilabel paper and the glass plate, and only the label paper breaks down.

○: Breaking of the label paper occurs in 30% or more and 90% or less of the adhesive area of the label paper.

× There is no breakage of the label paper at all, only interfacial peeling between the label paper and the glass plate occurs.

(Standard adhesion strength) After coating and pressing the test piece in the same manner as the test piece for initial adhesion measurement described above, the test piece was dried at 40°C for 24 hours and then cured for 3 days at 20°C and 65% RH, and then measured using an autograph. 180° peeling was performed under the same conditions to measure the normal adhesive strength. The results are shown using the same symbols as for the initial adhesive strength above.

(Cold water resistance) A test piece prepared in the same manner as the test piece for normal adhesion measurement was immersed in 10°C cold water (slowly stirring the cold water was continued to eliminate temperature unevenness) for 30 minutes.
After a day, the test piece was taken out of the cold water, and the cold water resistance between the glass plate surface and the label paper was measured by peeling it off with a finger or fingernail.

The results are shown with the following symbols.

◎: When peeled off with a fingernail, there was no peeling at the interface between the label paper and the glass plate; only the label paper was broken.

○: If you peel it off forcefully with your fingernails, only the interface between the label paper and the glass plate will peel off.

Δ, Peel off lightly with your fingernails! ! So, only the interfacial peeling between the label paper and the glass plate occurs.

×: Only the interfacial peeling between the label paper and the glass plate occurred easily by rubbing lightly with a finger.

(Alkaline cleaning property) Same as above! lFg! A test piece was prepared in the same way as the test piece for adhesion measurement (however, only the drying conditions were 40°C).
(for 48 hours) was immersed and held in a 3% NaOH aqueous solution at 70° C. so that the adhesive surface was vertical. Part 4
After 30 minutes and 30 minutes, it was observed whether the label paper would peel off from the glass plate and fall off naturally.

The results are shown with the following symbols.

◎The Nilabel paper completely falls off the glass plate.

○30% or more and 90% or less of the adhesive area of Nilabel paper peels off from the glass plate.

It does not peel off at all when it is attached to the glass plate with the strength of the paper.

(Odor) The adhesive was evaluated by sniffing it to see if it had a bad odor. The results are shown with the following symbols.

○: There is no odor.

△: Somewhat unpleasant odor.

×: There is a very unpleasant odor.

Implementation fM2 pvA41[1i (PVA-C5 manufactured by Kuraray, +tA, 97.5 mol%, polymerization degree 175G) 100 parts, styrene-maleic anhydride copolymer fine powder (manufactured by Arco; S
Example 1 using 50 parts of MA-too) and 500 parts of water
An adhesive was obtained in the same manner. The resulting adhesive was a mixture containing finely powdered styrene maleic anhydride in an aqueous PVA solution, and had good fluidity.

A summary of the composition and properties of the adhesive is shown in Table 1, and the evaluation results are shown in Table 2.

Example 3 PVAI! 100 parts of fat (Kuraray product PVA 217; degree of saponification 88.0 mol%, degree of polymerization 1750),
An adhesive was obtained in the same manner as in Example 1 using 50 parts of isobutylene maleic anhydride copolymer fine powder (Isopan-10, manufactured by Kuraray) and 500 parts of water. The composition and properties of the adhesive are shown in Table 1, and the evaluation results are shown in Table 2.

Example 4 100 parts of PVAMdwI (Kuraray product PVA-117: degree of saponification 98.5 mol%, degree of polymerization 1750), 10 parts of fine powder of the same isobutylene-maleic anhydride copolymer used in Example 3, clay After putting 150 parts into 550 parts of water, an adhesive was obtained in the same manner as in Example 1.

The successful adhesive was a mixture of fine particles of clay and isobutylene-maleic anhydride copolymer dispersed in an aqueous PVA solution, and had good fluidity. A summary of the composition and properties of the adhesive is shown in Table 1, and the evaluation results are shown in Table 2.

Example 5 Same as Example 4 except that the same fine powder of styrene-maleic anhydride copolymer used in Example 4 was used in place of the isobutylene-maleic anhydride copolymer used in Example 4. I did the same. The resulting adhesive was a mixture similar to Example 4. A summary of the composition and properties of the adhesive is shown in Table 1, and the evaluation results are shown in Table 2.

Example 6 Example 1 except that 50 parts of the same isobutylene-maleic anhydride copolymer fine powder used in Example 4 was used in place of the crotonic acid-modified polyvinyl acetate used in Example 1.
The adhesive was obtained in a similar manner.

Table 1 shows a summary of the properties of the blended composition and adhesive, and Table 2 shows the evaluation results.

Example 7 Instead of the isobutylene-maleic anhydride copolymer used in Example 4, a powder of a crosslinked isobutylene-maleic anhydride copolymer was added in an aqueous hydrochloric acid solution as an acid-type superabsorbent resin. After dealkalization treatment for 4 days, the mixture was washed with water, washed with methanol, and dried to obtain a powder. The obtained product was insoluble in water, insoluble in aqueous alkaline solutions, and exhibited particularly high swelling properties. The same procedure as in Example 4 was carried out using this acid type super absorbent resin. A summary of the composition and properties of the adhesive is shown in Table 1, and the evaluation results are shown in Table 2.

Example 8~l! In place of the isobutylene maleic anhydride copolymer Z used in Example 4, casein powder was used in Example 8.
In Example 9, acid type CMC (water-insoluble, alkali-soluble, carboxymethyl group-introduced cellulose manufactured by Daicel Chemical Industries) was used in Example 1O, cornstarch powder was used in Example 11, and aluminum powder was used in Example 4. I did the same thing. A summary of the properties is shown in Table 1, and the evaluation results are shown in Table 3.

Examples 12 to I8 Instead of PVA-117 used in Example 4, in Example 12, acetoacetylated PVA (acetoacetyl group content 12.3 mol%, saponification degree 99 mol%,
Degree of polymerization 1700), Example! In 3, silicon-containing modified P
Example 14 VA (vinylmethoxysilane modification degree 0.2 mol%, saponification degree 98 mol%, polymerization degree 1700)
Then, boxy-modified PVA (allyl glycidyl ether modification degree 2.5 mol%, saponification degree 98 mol%, polymerization degree 150
0), and in Example 15, carboxyl group-modified PVA (
In Example 16, ammonium group-modified P
In Example 17, VA (degree of modification with quaternary ammonium salt: 2 mol%, degree of saponification: 98 mol%, degree of polymerization: 1750) was used, and in Example 17, sulfonic acid group-modified PVA (degree of modification with sodium allylsulfonate: 2 mol%) was used.
mol%, saponification degree 98 mol%, polymerization degree 170G), and in Example 18, amide-modified PVA (acrylamide modification degree 2 mol%, saponification degree 98 mol%, polymerization degree 1700) was used in the same manner as in Example 5. I did it. Table 3 shows a summary of the composition and properties of the adhesive, and Table 4 shows the evaluation results.

Below is a margin Comparative Example 1 In place of PVA-117 with a saponification degree of 98.5 mol% used in the implementation fPI+, a saponification degree of 79.
The same procedure as in Example 1 was carried out except that a PVA-based resin (PVA-420 manufactured by Kuraray) having a polymerization degree of 175° and 5 mol % was used.

A summary of the composition and properties of the adhesive is shown in Table 5, and the evaluation results are shown in Table 6.

Comparative Example 2 The same procedure as in Example 1 was carried out except that a polyacrylic acid resin (Nippon Tsumugi Co., Ltd., Jurimar AC-10L P) was used in place of the crotonic acid-modified polyvinyl acetate used in Example I. . Table 5 shows the composition and properties of the adhesive, and Table 6 shows the evaluation results.

Comparative Example 3 The same procedure as in Example 1 was conducted except that PVC powder was used in place of the crotonic acid-modified polyvinyl acetate used in Example 1. Table 5 shows the composition and properties of the adhesive, and Table 6 shows the evaluation results.

Comparative Example 4 The same procedure as in Example 1 was conducted except that the crotonic acid-modified PVA used in Example 1 was not blended. A summary of the composition and properties of the adhesive is shown in Table 5, and the evaluation results are shown in Table 6.

Comparative Example 5 In place of the crotonic acid-modified polyvinyl acetate used in Example I, sodium polyacrylate (Rheosic 25 manufactured by Nippon Tsumugi Co., Ltd.) was used.
The same procedure as in Example 1 was conducted except that 0H') was used. What was obtained was a mixed aqueous solution of PVA and sodium polyacrylate, and the fine paper-like substance (B) as seen in Examples 1 to 10 was not present. A summary of the composition and properties of the adhesive is shown in Table 5, and the evaluation results are shown in Table 6.

Comparative Example 6 The same procedure as in Example 1 was carried out except that urea was used instead of the crotonic acid-modified polyvinyl acetate used in Example 1. A summary of the composition and properties of the adhesive is shown in Table 5, and the evaluation results are shown in Table 6.

Comparative Example 7 A test was conducted using an adhesive containing casein as a main component, which is currently used as an adhesive for label paper for beer bottles.

Solids concentration 38.5%, viscosity at 20'C 22.400
It had a cps% pH of 111.4 and a bad odor of ammonia. A summary of the composition and properties of the adhesive is shown in Table 5, and the evaluation results are shown in Table 6.

Margins below (Effects of the Invention) As is clear from the above examples, the adhesive of the present invention has a high initial adhesive strength and a particularly good balance between cold water resistance and alkaline cleanability. Therefore, cold water resistance is good when cooling a glass bottle filled with a beverage to which a label coated with the adhesive of the present invention is attached, and the label can be easily peeled off by alkali after the glass bottle is collected. It is especially useful as an adhesive for labels on beverage glass bottles.It is also suitable for high-speed automation,
It has extremely high industrial value, as it can be suitably used as an adhesive for labels on beverage bottles and the like.

Claims (8)

[Claims] (1) For labels containing as active ingredients a polyvinyl alcohol resin (A) with a saponification degree of 85 to 100 mol% and a water-insoluble, alkali-soluble and/or alkali-swellable substance (B) adhesive. (2) Polyvinyl alcohol resin (A) has a saponification degree of 9
The adhesive for labels according to claim 1, which has a content of 0 to 100 mol%. (3) A claim in which the water-insoluble and alkali-soluble and/or alkali-swellable substance (B) is one or more selected from α-olefin-maleic anhydride copolymers and acid-modified polyvinyl esters. Adhesive for labels described in 1. (4) The adhesive for labels according to claim 1, wherein the water-insoluble and alkali-soluble and/or alkali-swellable substance (B) is an isobutylene-maleic anhydride copolymer. (5) The adhesive for labels according to claim 1, wherein the water-insoluble and alkali-soluble and/or alkali-swellable substance (B) is a styrene-maleic anhydride copolymer. (6) The label according to any one of claims 1 to 5, characterized in that the water-insoluble and alkali-soluble and/or alkali-swellable substance (B) is present in particulate form in the adhesive. adhesive for. (7) 1 selected from claims 1 to 6 on the surface of the glass substrate
A glass substrate with a label coated with the label adhesive described in Section 1. (8) The glass substrate according to claim 7, wherein the glass substrate is a glass bottle.