JPH0885777A - Adhesive composition and paper tube produced by using the same - Google Patents

Abstract

PURPOSE: To obtain an adhesive composition based on a vinyl acetate resin emulsion giving a film excellent in strengths, initial tack and water resistance and having good long-term stability (storage stability) and to prepare a paper tube produced by using the same. CONSTITUTION: This composition comprises 100 pts.wt. (in terms of solid matter) vinyl acetate resin emulsion obtained by emulsion-polymerizing a vinyl acetate monomer alone or with a monomer copolymerizable therewith in the presence of a protective colloid prepared by making a carboxyl-modified polyvinyl alcohol, an α-olefin/unsaturated carboxylic acid copolymer or a derivative thereof water-soluble with the aid of a basic substance and 0.1-10 pts.wt. urea. A tube is produced by using this composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an adhesive composition containing a vinyl acetate resin emulsion as a main component, which is used for paper tubes, paper packaging, woodworking, general purposes, etc., and the adhesive composition. The present invention relates to a paper tube made by using the paper tube.

[0002]

2. Description of the Related Art A paper tube is manufactured by winding a strip of paper on a metal core in a plurality of layers and adhering the polymerized portion of the strip of paper with an adhesive. The adhesive used in this case is , Based on one or more of aqueous solutions of starch, polyvinyl alcohol and the like, and vinyl acetate resin emulsions using polyvinyl alcohol as a protective colloid.

On the other hand, an adhesive for paper tubes is required to have an initial adhesive strength that can withstand the restoring force of a strip of paper wound around a metal core, an adhesive strength after making a paper tube, water resistance, and pressure resistance. .

Emulsion type adhesive compositions based on vinyl acetate resins generally have poor water resistance. Therefore, in order to improve the water resistance of this adhesive composition, an alkyl group having 2 to 14 carbon atoms and a carboxyl group are used. A so-called carboxyl group-modified polyvinyl alcohol having a protective colloid, vinyl acetate monomer alone or a mixture of vinyl acetate monomer and a copolymerizable comonomer 80 to 99.
A method of obtaining a vinyl acetate resin emulsion adhesive composition by emulsion copolymerizing a monomer composed of 8% by weight and 0.2 to 20% by weight of an unsaturated carboxylic acid has been proposed (JP-A-2-28203). Gazette).

However, although the vinyl acetate resin emulsion adhesive composition using the carboxyl group-modified polyvinyl alcohol as a protective colloid as proposed above has improved water resistance, its viscosity tends to increase with time, and There is a problem that the viscosity stability (storage stability) is poor.

As a method for obtaining a vinyl acetate resin emulsion adhesive composition having a high film elastic modulus and a high film strength in order to improve the adhesive strength and pressure resistance of a paper tube, α-olefin and an unsaturated carboxylic acid are used. A vinyl acetate resin emulsion obtained by emulsion polymerization of a reaction product obtained by adding a basic substance to a copolymer or its derivative to form an aqueous solution, and reacting the unsaturated carboxylic acid with a peroxide as a protective colloid. And an benzyl alcohol, which may be substituted with an alkyl group, or an alkyl carbitol, or a glycol monophenyl ether is added to the adhesive composition. Japanese Patent Publication No. 60-54993).

However, a basic substance is added to the copolymer of α-olefin and unsaturated carboxylic acid or a derivative thereof as proposed above to form an aqueous solution, and the unsaturated carboxylic acid and peroxide are reacted with this. Although the vinyl acetate resin emulsion adhesive composition using the reaction product as a protective colloid improves the film elastic modulus, it still has a problem that the viscosity tends to increase with time and the viscosity stability over time is poor. is there.

[0008]

In order to solve the above-mentioned conventional problems, the present invention has excellent film strength, initial adhesive strength, water resistance and the like, and has good viscosity stability over time (storage stability). An object of the present invention is to provide an adhesive composition containing a vinyl acetate resin emulsion as a main component, and a paper tube produced by using the adhesive composition.

[0009]

The adhesive composition according to the invention of claim 1 (hereinafter referred to as the "first invention") comprises a carboxyl group-modified polyvinyl alcohol as a protective colloid, vinyl acetate monomer alone or acetic acid. 0.1 to 10 parts by weight of urea is contained per 100 parts by weight of solid content of a vinyl acetate resin emulsion obtained by emulsion polymerization of a vinyl monomer and a monomer copolymerizable with the vinyl acetate monomer. Characteristically, the above-mentioned object is achieved thereby.

The adhesive composition according to the invention of claim 2 (hereinafter referred to as "second invention") is a copolymer of α-olefin and unsaturated carboxylic acid or a derivative thereof as a basic substance. A solid content of a vinyl acetate resin emulsion obtained by emulsion-polymerizing a vinyl acetate monomer alone or a vinyl acetate monomer and a monomer copolymerizable with the vinyl acetate monomer, using a water-solubilized product as a protective colloid.
It is characterized in that 0.1 to 10 parts by weight of urea is contained with respect to 0 parts by weight, whereby the above object is achieved.

Further, in a paper tube according to the invention of claim 3 (hereinafter referred to as "third invention"), a strip-shaped paper piece is wound in a tubular shape, and the overlapped portion of the tubular paper piece wound in the tubular shape is It is characterized by being bonded by the adhesive composition according to the first invention or the second invention.

The monomer copolymerizable with the vinyl acetate monomer used in the vinyl acetate resin emulsion, which is the main component of the adhesive composition according to the first and second inventions, is not particularly limited. (Meth) acrylic acid, methyl (meth) acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethylene glycol di (meth) acrylate, glycidyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol (meth) acrylate And the like, and one or more of these are preferably used. The term "(meth) acrylic" used here means "acrylic" or "methacrylic".
Say

In the vinyl acetate resin emulsion which is the main component of the adhesive composition according to the first invention, it is necessary to use a carboxyl group-modified polyvinyl alcohol as a protective colloid during emulsion polymerization.

The degree of saponification of the carboxyl group-modified polyvinyl alcohol is not particularly limited, but is 80
˜99 mol% is preferable, and 94 to 98 mol% is more preferable. If the degree of saponification is less than 80 mol%, the water resistance of the dry film of the adhesive composition obtained will decrease, and if it exceeds 99 mol%, the stability during emulsion polymerization will deteriorate.

The average degree of polymerization of the above-mentioned carboxyl group-modified polyvinyl alcohol is not particularly limited, but it is preferably from 1000 to 2500, and among them, 1
It is more preferably 500 to 2000. If the average degree of polymerization is less than 1000, the dry film strength of the obtained adhesive composition will be weak, and if it exceeds 2,500, the viscosity of the obtained adhesive composition will be too high.

The amount of the above carboxyl group-modified polyvinyl alcohol used as a protective colloid is not particularly limited, but may be 100 parts by weight of vinyl acetate monomer or vinyl acetate monomer and a monomer copolymerizable with the vinyl acetate monomer. The carboxyl group-modified polyvinyl alcohol is preferably 0.1 to 30 parts by weight, and more preferably 5 to 20 parts by weight, based on 100 parts by weight in total.

The amount of the carboxyl group-modified polyvinyl alcohol is 100 parts by weight based on 100 parts by weight of the vinyl acetate monomer.
When it is less than 1 part by weight, it becomes difficult to cause initial polymerization,
On the contrary, when it exceeds 30 parts by weight, the dry film strength of the obtained adhesive composition becomes weak.

In the vinyl acetate resin emulsion according to the first aspect of the present invention, in addition to the above-mentioned carboxyl group-modified polyvinyl alcohol, ordinary unmodified polyvinyl alcohol and α may be used, as required, within a range that does not impair the object of the present invention.
-A copolymer of olefin and unsaturated carboxylic acid or a derivative thereof made water-soluble with a basic substance may be used in combination as a protective colloid.

Next, in the vinyl acetate resin emulsion which is the main component of the adhesive composition according to the second aspect of the present invention, a copolymer of α-olefin and unsaturated carboxylic acid or a copolymer thereof is used as a protective colloid during emulsion polymerization. It is necessary to use a derivative which is water-solubilized with a basic substance.

The α-olefin in the above-mentioned copolymer of α-olefin and unsaturated carboxylic acid or its derivative is not particularly limited, but ethylene, propylene, n-butene, isobutylene, n-pentene, Isoprene and the like are mentioned, and one kind or two or more kinds thereof are preferably used, and among them, isobutylene is more preferably used.

The unsaturated carboxylic acid is not particularly limited, but acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, etc. may be mentioned, and one or two of these may be mentioned. The above is preferably used, but maleic anhydride is more preferably used.

Specific examples of the above-mentioned copolymer of α-olefin and unsaturated carboxylic acid include isoban (manufactured by Kuraray Co., Ltd.), which is a copolymer of isobutylene and maleic anhydride. And a partially imidized product of isoban which is more excellent in water resistance, and any of them is preferably used in the second invention.

The above-mentioned copolymer of α-olefin and unsaturated carboxylic acid and its derivative are insoluble in water, but should be made water-soluble by adding a basic substance such as caustic alkali, alkali carbonate or ammonia. Can be done. The basic substance is preferably added in an amount of 0.3 to 0.8 equivalents based on the amount of the carboxyl group of the above-mentioned copolymer of α-olefin and unsaturated carboxylic acid or its derivative. More preferably, it is 35 to 0.45 equivalent.
If the amount added is less than 0.3 equivalent, it is difficult to make the copolymer of α-olefin and unsaturated carboxylic acid or its derivative water-soluble, and conversely the amount added exceeds 0.8 equivalent. Then, the alkalinity of the aqueous solution becomes too high, and emulsion polymerization of the vinyl acetate-based monomer becomes slow or difficult.

The amount of the above-mentioned copolymer of α-olefin and unsaturated carboxylic acid or its derivative used as a protective colloid is not particularly limited, but is 100 parts by weight of vinyl acetate monomer or vinyl acetate monomer. Total amount of vinyl acetate monomer and copolymerizable monomer 1
10 parts by weight of the above-mentioned copolymer or its derivative is used per 100 parts by weight
It is preferably from 50 to 50 parts by weight, and especially from 15 to 3
It is more preferably 0 part by weight.

When the amount of the copolymer of α-olefin and unsaturated carboxylic acid or its derivative is less than 10 parts by weight with respect to 100 parts by weight of the vinyl acetate monomer, the minimum film forming temperature of the adhesive composition obtained is If it exceeds 50 parts by weight, the emulsion polymerization property becomes poor, the initial polymerization time becomes long, and the residual monomer content and the amount of coarse particles also increase.

In the vinyl acetate resin emulsion according to the second aspect of the invention, the copolymer of α-olefin and unsaturated carboxylic acid or a derivative thereof may be added, if necessary, within a range that does not impair the object of the invention. In addition to water-solubilized basic substances, ordinary unmodified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol and the like may be used together as a protective colloid.

The vinyl acetate resin emulsion according to the first or second invention does not depend on a special polymerization method, but the carboxyl group-modified polyvinyl alcohol or a copolymer of the above α-olefin and an unsaturated carboxylic acid, or a copolymer thereof. Reduction of hydrogen peroxide or peroxides such as persulfates such as ammonium persulfate, potassium persulfate, sodium persulfate, etc. and tartaric acid, formic acid, oxalic acid, etc. by using water-soluble derivatives of basic derivatives as protective colloids 1 such as agents
It can be obtained by emulsion polymerization according to a conventional method, using one kind or two or more kinds as a polymerization catalyst.

The amount of the above-mentioned polymerization catalyst is not particularly limited, but is based on 100 parts by weight of vinyl acetate monomer or 100 parts by weight of the total amount of the vinyl acetate monomer and the monomer copolymerizable with the vinyl acetate monomer. The polymerization catalyst is preferably 0.01 to 2 parts by weight.

The adhesive composition according to the first and second aspects of the invention comprises the vinyl acetate resin emulsion obtained above as a main component, and the solid content of the vinyl acetate resin emulsion is 1%.
It is necessary that urea is contained in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 00 parts by weight.

If the content of urea is less than 0.1 parts by weight based on 100 parts by weight of the solid content of the vinyl acetate resin emulsion, the viscosity stability of the resulting adhesive composition with time cannot be sufficiently improved, and conversely. When it exceeds 10 parts by weight, the initial adhesive strength of the obtained adhesive composition is lowered.

In the adhesive composition according to the first invention and the second invention, in addition to the above-mentioned urea, a tackifying resin, a surfactant, a plasticizer, a filler, if necessary, within a range not impairing the object of the present invention. Various additives such as pigments, dyes, defoaming agents, preservatives and organic solvents may be contained.

Needless to say, the adhesive compositions according to the first and second inventions are not limited to those for paper tubes, but can be suitably used for paper packaging, woodworking, general purposes, etc.

[0033]

The adhesive composition according to the first invention has a vinyl acetate resin emulsion obtained by using a carboxyl group-modified polyvinyl alcohol as a protective colloid as a main component, and therefore has excellent initial adhesive strength and water resistance and, Since urea is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the solid content of the vinyl resin emulsion, the urea blocks a carboxyl group in the vinyl acetate resin emulsion and serves as a filler such as a filler. It exhibits good viscosity stability over time (storage stability) to prevent reaction.

The adhesive composition according to the second invention is α-
As a main component is vinyl acetate resin emulsion obtained as a protective colloid of water-solubilized copolymer of olefin and unsaturated carboxylic acid or its derivative, it has excellent film strength and initial adhesive strength. And the solid content of the vinyl acetate resin emulsion is 100.
Since 0.1 to 10 parts by weight of urea is contained with respect to parts by weight, good viscosity stability with time (storage stability) is exhibited for the same reason as in the case of the adhesive composition according to the first invention. .

Furthermore, since the paper tube according to the third aspect of the invention is manufactured using the adhesive composition according to the first aspect or the second aspect of the invention, the workability at the time of tube production is good, and the adhesive strength and water resistance are good. Excellent in pressure resistance.

[0036]

EXAMPLES In order to explain the present invention in more detail, examples will be given below. In the examples, "part" means "part by weight" and "%" means "% by weight".

(Example 1)

(1) Weight of vinyl acetate resin emulsion
In a reaction vessel equipped with a combined stirrer, a reflux condenser, a thermometer, and a dropping funnel, 125 parts of water and carboxyl group-modified polyvinyl alcohol (trade name "Kuraray PVA K Polymer KL1.
18 ", saponification degree 96 mol%, average degree of polymerization 1700, manufactured by Kuraray Co., Ltd.), and heated at 95 ° C for 1 hour with stirring to obtain an aqueous solution of carboxyl group-modified polyvinyl alcohol. Next, this aqueous solution was cooled to 70 ° C., and 5 parts of vinyl acetate monomer and a polymerization catalyst (hydrogen peroxide 0.
1 part and tartaric acid (0.1 part) were added to carry out initial polymerization. Then, 95 parts of vinyl acetate monomer and a polymerization catalyst (0.4 parts of hydrogen peroxide and 0.4 parts of tartaric acid) were added dropwise to 70 parts.
After emulsion polymerization was carried out at 70 ° C, it was aged at 70 ° C for 1 hour to obtain a vinyl acetate resin emulsion having a viscosity of 6000 cps (30 ° C) and a solid content of 47%.

(2) Preparation of adhesive composition

To 100 parts of the solid content of the vinyl acetate resin emulsion obtained above, 2 parts of urea, 15 parts of dibutyl phthalate (DBP) and water were added and mixed to give a viscosity of 4
An adhesive composition of 000 cps (30 ° C.) was obtained.

(3) Evaluation The various performances of the obtained adhesive composition were evaluated by the following methods, and the results are shown in Table 1. The evaluation was carried out in an atmosphere of 20 ° C.-65% RH unless otherwise specified.

Coating elastic modulus The adhesive composition was applied onto a polyethylene plate, and the temperature was 20 ° C.-6.
A thickness of 3 after curing for 7 days in an atmosphere of 5% RH
A dry film having a thickness of 00 to 500 μm was punched out with a No. 1 dumbbell to prepare a test piece. Then, this test piece was set in a tensile tester and pulled at a pulling speed of 10 mm / min, and the film elastic modulus (kg / cm ² ) was determined from the tensile strength and elongation at 20 to 70% of the maximum strength.

Initial adhesive strength (material breaking time) Two pieces of class B paper tube base paper (manufactured by Okayama Paper Co., Ltd.) cut into 20 mm × 40 mm were used as test pieces, and one surface of one of the test pieces was coated with the adhesive composition. 20mm × 30mm, coating amount 3
Immediately after the application of 0 g / m ² , the other test piece was attached to the application surface so that the adhesion area was 20 mm × 30 mm, and the attachment part was 70 g / c.
A large number of adhesion test pieces were prepared by pressing under a pressure of m ² for 5 seconds. Next, the adhesive test piece was peeled off by hand every 10 seconds after depressurization, and the fracture area ratio of the adhesive portion of the base paper for class B paper tube was 100%.
The shortest time (seconds) to reach was measured.

Two sheets of base paper for a class B paper tube similar to the above, which were cut to a water drop time of 25 mm × 50 mm, were used as test pieces, and the adhesive composition was applied to one half of one of the test pieces at an application area of 25 mm × 25 mm. The amount of 0.05 g / (25 mm) ² is applied, and half of one side of the other test piece is alternately affixed to this application surface, and the affixed portion is applied at a pressure of 1 kg / (25 mm) ² for 60 seconds. After pressure bonding, it was cured for 24 hours in an atmosphere of 20 ° C.-65% RH to prepare an adhesive test piece. Then, a weight of 100 g was suspended at the lower end of one of the adhesive test pieces and vertically immersed in warm water of 60 ° C., and the shortest time (minute) until the test piece peeled off and dropped. It was measured.

Change in viscosity with time Using 200 g of the above adhesive composition taken in a glass bottle as a sample, the initial viscosity (cps) at 30 ° C. was measured with a B type rotational viscometer. Then, the sample is sealed with the stopper 40
Leave it in a constant temperature room at ℃
After allowing to cool for a period of time, the viscosity with time (cps) at 30 ° C. was measured for 3 months in the same manner as above.

(Example 2)

A viscosity of 6200 was obtained in the same manner as in Example 1 except that a mixed monomer of 98 parts of vinyl acetate monomer and 2 parts of ethylene glycol dimethacrylate was used as a monomer in the polymerization of the vinyl acetate resin emulsion.
A vinyl acetate resin emulsion having a cps (30 ° C.) and a solid content of 47% was obtained.

Then, in the preparation of the adhesive composition, the viscosity was 4000 cps in the same manner as in Example 1 except that the vinyl acetate resin emulsion obtained above was used.
An adhesive composition (30 ° C.) was obtained.

(Comparative Example 1)

In the polymerization of a vinyl acetate resin emulsion, an ordinary unmodified polyvinyl alcohol (saponification degree: 96 mol%, average polymerization degree: 1700) was used as a protective colloid instead of the carboxyl group-modified polyvinyl alcohol.
A viscosity of 60 was obtained in the same manner as in Example 1 except that parts were used.
A vinyl acetate resin emulsion having a solid content of 47% at 00 cps (30 ° C.) was obtained.

Then, in the preparation of the adhesive composition, a viscosity of 3700 cps was obtained in the same manner as in Example 1 except that the vinyl acetate resin emulsion obtained above was used.
An adhesive composition (30 ° C.) was obtained.

(Comparative Example 2)

In the preparation of the adhesive composition, the vinyl acetate resin emulsion obtained in Example 1 was used, and the amount of urea was 100 parts by weight based on 100 parts by weight of the solid content of the emulsion.
A viscosity of 4 was obtained in the same manner as in Example 1 except that the amount was changed to 05 parts.
An adhesive composition of 000 cps (30 ° C.) was obtained.

(Comparative Example 3)

In the preparation of the adhesive composition, the vinyl acetate resin emulsion obtained in Example 1 was used, and the amount of urea was 15 per 100 parts by weight of the solid content of the emulsion.
A viscosity of 400 was obtained in the same manner as in Example 1 except that the viscosity was 400 parts.
An adhesive composition of 0 cps (30 ° C.) was obtained.

Table 1 shows the results of evaluating various performances of the adhesive compositions obtained in Example 2 and Comparative Examples 1 to 3 in the same manner as in Example 1.

[0057]

[Table 1]

(Example 3)

In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 81 parts of water and a water-soluble product of a partially imidized copolymer of isobutylene and maleic anhydride (trade name "Isoban 304S"). , Evaporation residue 27%, PH
= 4.7, manufactured by Kuraray Co., Ltd.) 90 parts (evaporation residue 24.3 parts)
Was charged and heated at 95 ° C. for 1 hour while stirring to obtain an aqueous solution of “isoban 304S”. Next, add 7
After cooling to 0 ° C., 5 parts of vinyl acetate monomer and a polymerization catalyst (0.1 part of hydrogen peroxide and 0.1 part of tartaric acid) were added thereto to carry out initial polymerization. Then vinyl acetate monomer 9
5 parts and polymerization catalyst (0.4 parts hydrogen peroxide and 0.4 tartaric acid)
Part) and emulsion polymerization was performed at 70 ° C., followed by aging for 1 hour at 90 ° C. to obtain a vinyl acetate resin emulsion having a viscosity of 2000 cps (30 ° C.) and a solid content of 46%.

2.2 parts of urea and 1 part of DBP were added to 100 parts of the solid content of the vinyl acetate resin emulsion obtained above.
Add 5 parts of water and mix to give a viscosity of 2000 cps (30
An adhesive composition of (° C.) was obtained.

(Example 4)

Example 3 was repeated except that the vinyl acetate resin emulsion obtained in Example 3 was used in the preparation of the adhesive composition, and the amount of urea was 4.4 parts per 100 parts of the solid content of the emulsion. And the viscosity is 2000
An adhesive composition of cps (30 ° C.) was obtained.

(Example 5)

In the polymerization of the vinyl acetate resin emulsion, a viscosity of 2000 cps (30 ° C.) and a solid content were obtained in the same manner as in Example 3 except that a mixed monomer of 98 parts of vinyl acetate monomer and 2 parts of acrylic acid was used as a monomer. A 46% vinyl acetate resin emulsion was obtained.

Then, in the preparation of the adhesive composition, a viscosity of 2000 cps was obtained in the same manner as in Example 3 except that the vinyl acetate resin emulsion obtained above was used.
An adhesive composition (30 ° C.) was obtained.

(Comparative Example 4)

In the preparation of the adhesive composition, the vinyl acetate-based resin emulsion obtained in Example 3 was used, and the amount of urea was 0.05 based on 100 parts of the solid content of the emulsion.
A viscosity of 200
An adhesive composition of 0 cps (30 ° C.) was obtained.

(Comparative Example 5)

In the preparation of the adhesive composition, the same procedure as in Example 3 was carried out except that the vinyl acetate resin emulsion obtained in Example 3 was used and the amount of urea was 15 parts per 100 parts of the solid content of the emulsion. And viscosity 2000c
An adhesive composition of ps (30 ° C.) was obtained.

(Comparative Example 6)

In the polymerization of a vinyl acetate resin emulsion, a conventional unmodified polyvinyl alcohol (saponification degree: 96) was used instead of "isoban 304S" as a protective colloid.
Mol%, average degree of polymerization 1700) The same procedure as in Example 3 except that 11 parts was used, the viscosity was 4000 cps (30
A vinyl acetate resin emulsion having a solid content of 46% was obtained.

Then, in the preparation of the adhesive composition, the vinyl acetate resin emulsion obtained above was used, and the procedure of Example 3 was repeated except that urea was not added.
An adhesive composition having a viscosity of 2000 cps (30 ° C.) was obtained.

Table 2 shows the results of evaluation of various performances of the adhesive compositions obtained in Examples 3 to 5 and Comparative Examples 4 to 6 in the same manner as in Example 1.

[0074]

[Table 2]

[0075]

As described above, the adhesive composition according to the first aspect of the present invention has excellent initial adhesive strength and water resistance, and has little change in viscosity over time. Further, the adhesive composition according to the second invention has excellent film strength and initial adhesive strength, and has little change in viscosity with time. Furthermore, the first invention or the second invention
The paper tube according to the third aspect of the present invention, which is produced using the adhesive composition according to the present invention, has good workability in producing the tube, and also has excellent adhesive strength, water resistance, and pressure resistance.

Claims (3)

[Claims] 1. A solid of a vinyl acetate-based resin emulsion obtained by using a carboxyl group-modified polyvinyl alcohol as a protective colloid and emulsion-polymerizing a vinyl acetate monomer alone or a vinyl acetate monomer and a monomer copolymerizable with the vinyl acetate monomer. An adhesive composition comprising 0.1 to 10 parts by weight of urea per 100 parts by weight of the adhesive. 2. A vinyl acetate monomer alone or a vinyl acetate monomer and said vinyl acetate monomer, which is made of a copolymer of α-olefin and unsaturated carboxylic acid or a derivative thereof water-solubilized with a basic substance as a protective colloid. An adhesive composition containing 0.1 to 10 parts by weight of urea per 100 parts by weight of a solid content of a vinyl acetate-based resin emulsion obtained by emulsion polymerization of a monomer copolymerizable with . 3. The strip-shaped paper piece is wound in a tubular shape, and the polymerized portion of the tubular paper piece wound in a tubular shape is adhered by the adhesive composition according to claim 1 or 2. Paper tube.