JPH093427A - Adhesive - Google Patents

Abstract

PURPOSE: To obtain an adhesive excellent in blocking resistance and the preservability in its aqueous solution state, thus useful as esp. a remoistening adhesive, consisting mainly of a new polyvinyl alcohol-based resin copolymerized with a specific modifying component. CONSTITUTION: This adhesive consists mainly of a polyvinyl alcohol(PVA)-based resin copolymerized with 1-20mol% of an ethylenic unsaturated dicarboxylic acid monoamide having an amide component of formula I [R0 is of formula II ((n) is 1-3; R1 to R3 are each H, an alkyl or aryl; at least tow of them are not H simultaneously, and the number of carbon atoms for R1 to R3 is >=4)] (pref. N,N-diisobutylmaleic acid monoamide). The PVA-based resin is normally obtained by saponification of a copolymer of the above monoamide and a vinyl ester (pref. vinyl acetate). The monoamide is prepared, for example, by reaction of an ethylenic unsaturated dicarboxylic acid such as maleic acid with a secondary amine such as diisobutylamine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive using polyvinyl alcohol (hereinafter abbreviated as PVA), and more specifically, to a blocking resistance when a novel PVA resin is used as a rewetting adhesive. Excellent adhesive.

[0002]

2. Description of the Related Art Conventionally, PVA has been used as a rewetting adhesive for packaging tape, various labels, stamps, stamps, shoji paper,
It is used as a backing paste for wallpaper, fusuma paper, posters, etc., or as an aqueous solution as it is, as an adhesive for various packaging such as cardboard and bag making, and as an office glue. Furthermore, as a hot melt adhesive, bookbinding, bag making, box making, packaging, woodworking, shoe making,
It is used in various adhesives for applications such as fibers.

[0003]

SUMMARY OF THE INVENTION However, PVA
When used for adhesive, in rewetting adhesive,
Blocking of the base material after applying the PVA to the base material, and blocking of the hot melt adhesive during storage in the form of pellets, powders, etc. become a problem, and further rewetting adhesive, pressure sensitive adhesive, etc. In the adhesive used in the form of
There is often a problem also in its storage stability (blocking resistance further decreases when stored for a long time), and a PVA-based resin adhesive excellent in blocking resistance and storage stability has been desired. Of.

[0004]

Means for Solving the Problems As a result of intensive studies in view of such circumstances, the present inventor has found that an ethylenically unsaturated dicarboxylic acid containing an N, N-dibranched alkylamide component represented by the following chemical formula 1 as a modifying component. The acid monoamide (A) was added to 0.
It was found that a novel PVA-based resin containing 1 to 20 mol% of a copolymer component is excellent in blocking resistance and storage stability when it is used for an adhesive, and the present invention has been completed.

Embedded image Here, R ₀ is shown in Chemical formula 2.

Embedded image (However, n is 1 to 3, R _{1 to} R ₃ are each hydrogen or an alkyl group or an aryl group, and two or more are not hydrogen at the same time, and the total number of carbon atoms of R _{1 to} R ₃ is 4 That is all.)

Hereinafter, the present invention will be described in detail. The modified PVA (hereinafter sometimes simply referred to as modified PVA) -based resin of the present invention contains the (A) unit as an essential component as described above, and the (A) unit is the N, N-dicarboxylic acid represented by Chemical Formula 1 above. modified carbon number of functional groups of R ₁ to R ₃ in having the functional group of R ₁ to R ₃ in ethylenically unsaturated dicarboxylic acid monoamide units containing branched alkyl amide component, during saponification is less than 4 The stability of the group and the storage stability of the aqueous solution when it is applied to a rewetting adhesive and the like are poor, and the carbon number is preferably 4 to 16
It is.

As the copolymerizable monomer containing the (A) unit, N, N-diisobutyl maleic acid monoamide, N, N-diisoamyl maleic acid monoamide, N, N
N-di (2-ethylhexyl) maleic acid monoamide,
N, N-diisobutyl fumaric acid monoamide, N, N-diisoamyl fumaric acid monoamide, N, N-di (2-ethylhexyl) fumaric acid monoamide, N, N-diisobutylitaconic acid monoamide, N, N-diisoamylitaconic acid Monoamide, N, N-di (2-ethylhexyl) itaconic acid monoamide, N, N-diisobutyl citraconic acid monoamide, N, N-diisoamyl citraconic acid monoamide, N, N-di (2-ethylhexyl) citraconic acid monoamide, etc. Of these, N, N-diisobutyl maleic acid monoamide is preferably used. The carboxylic acid component in the unit (A) of the modified PVA-based resin of the present invention is a free carboxyl group or a salt thereof.

Usually, in order to produce the PVA resin of the present invention, the vinyl ester copolymer obtained by copolymerizing (A) and the vinyl ester (B) is saponified. Examples of (B) include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, and the like, and vinyl acetate is preferable from the economical viewpoint.

With respect to the ratio of each unit of the modified PVA-based resin, 0.1 to 0.1 of the ethylenically unsaturated dicarboxylic acid monoamide unit (A) containing the N, N-dibranched alkylamide component shown in Chemical formula 1 above is used. 20 mol%, preferably 0.3 to 10 mol%, and the total range of vinyl ester unit (B) and vinyl alcohol unit (C) is suitably 80 to 99.9 mol%. The degree of saponification (the ratio of the vinyl alcohol unit (C) to the total amount of the vinyl ester unit (B) and the vinyl alcohol unit (C)) is not particularly limited, but when the formed film is water-soluble. It is preferably 70 mol% or more, and particularly preferably 75 mol% or more.

The degree of polymerization of the modified PVA resin used in the present invention is not particularly limited, but is preferably 100 to 2500, more preferably 300 to 2000, and the degree of polymerization is 10.
If it is less than 0, the adhesiveness will decrease, and if it exceeds 2500, P
Since the viscosity of the VA aqueous solution increases, the workability of a solution adhesive tends to be poor.

Next, the method for producing the modified PVA resin of the present invention will be described. The modified PVA-based resin of the present invention saponifies the copolymer of the above-mentioned ethylenically unsaturated dicarboxylic acid monoamide monomer containing the N, N-dibranched alkylamide component represented by Chemical Formula 1 and vinyl ester. Obtained by

Such ethylenically unsaturated dicarboxylic acid monoamides (A) include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid,
An ethylenically unsaturated dicarboxylic acid such as citraconic anhydride or an anhydride thereof, or an acid halide thereof is used with a secondary amine represented by Chemical formula 3 without catalyst or with a suitable acid catalyst (sulfuric acid,
It can be obtained by reacting in the presence of hydrochloric acid, a protonic acid such as P-toluenesulfonic acid). Such amines include diisobutylamine, diisoamylamine,
Di (2-ethylhexyl) amine may be mentioned.

Embedded image Here, R ₀ is shown in Chemical formula 2.

Embedded image (However, n is 1 to 3, R _{1 to} R ₃ are each hydrogen or an alkyl group or an aryl group, and two or more are not hydrogen at the same time, and the total number of carbon atoms of R _{1 to} R ₃ is 4 or more.)

The copolymerization reaction can be arbitrarily selected from known polymerization methods such as radical polymerization, for example, bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc., but solution polymerization is preferred from the industrial viewpoint. Further, any method such as batch polymerization and continuous polymerization can be adopted. There are no particular restrictions on the method of charging the monomers during the polymerization, and any method such as batch charging, divided charging, continuous charging may be employed. Branched alkyl acrylamide and ethylenically unsaturated carboxylic acid or salts thereof are used as PVA molecules. A divided charging method or a continuous charging method is advantageous in that it can be uniformly introduced into the inside.

As a catalyst for the copolymerization, known radical polymerization catalysts such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, and lauryl peroxide, and low-temperature catalysts such as azobisdimethylvaleronitrile and azobismethoxydimethylvaleronitrile. An active radical catalyst or the like is used. Further, the reaction temperature is not particularly limited and is appropriately selected from the range well known to those skilled in the art.

In such polymerization, other unsaturated monomers copolymerizable with the monomers other than the above-mentioned two components, such as alkyl vinyl ether, methacrylamide, ethylene, propylene and α, can be used as long as they do not impair the gist of the present invention. −
Olefin such as hexene, α-octene, α-dodecene, α-octadodecene, nitriles such as acrylonitrile and methacrylonitrile, alkyl acrylate, alkyl methacrylate, alkyl crotonic acid, dialkyl maleate, dialkyl itaconate A small amount of ester, citraconic acid dialkyl ester, fumaric acid dialkyl ester and the like may be copolymerized.

The copolymer obtained by such a method is then saponified. As the saponification method, any method such as kneader saponification, continuous saponification, and pearl saponification can be adopted. In the saponification step, the residual monomer is expelled as necessary, and then saponification is performed according to a conventional method. To be done. Examples of the catalyst used for saponification include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate and potassium methylate, alkali catalysts such as alcoholate, sulfuric acid, hydrochloric acid and the like. An acid catalyst is used.

The saponification reaction temperature is not particularly limited and is usually selected in the range of 10 to 60 ° C, preferably 20 to 50 ° C. After the saponification reaction is completed, the target modified PVA-based resin is obtained by neutralizing, washing with alcohol or the like, if necessary, and drying. Next, an adhesive using the obtained modified PVA-based resin will be described. The PVA-based resin can be used for various adhesives such as rewetting adhesives, hot-melt adhesives, pressure-sensitive adhesives, etc., in addition to general adhesives in which the resin is made into an aqueous solution, but it has blocking resistance. Are very useful as rewetting adhesives and hot melt adhesives, and will be described in more detail.

First, when used as a rewetting adhesive,
After the above PVA-based resin is made into an aqueous solution, it is applied to a base material such as gum tape or stamp and dried. At this time, alcohols such as methanol and ethanol and glycols such as ethylene glycol, propylene glycol, polyethylene glycol and glycerin may be added, if necessary. The coating can be performed by a known method such as a gravure coater, a reverse roll coater, an air knife coater, and a spray. It is also possible to form a rewetting adhesive layer by hot-melt coating.

When used as a hot melt adhesive, a plasticizer (glycols such as ethylene glycol, propylene glycol, polyethylene glycol, and glycerin, urea derivatives such as ethylene urea, etc.) is usually added to 100 parts by weight of the above PVA resin. 5 to 50 parts by weight of hydrophobic resin (ethylene-vinyl acetate copolymer, phenol resin, styrene resin, polyester resin,
5 to 60 parts by weight of a polyamide resin, etc. is blended,
Furthermore, well-known additives for hot-melt adhesives such as hydroxy fatty acids, rosins, rosin esters, pinene-based polymers, hydrogenated petroleum resins, hydrocarbon resins, antioxidants, lubricants, fillers, and colorants. , Fragrance, stabilizer and the like are blended. The coating is carried out by a known hot melt coating machine such as roll, die, nozzle, lip, etc., which can be used for binding bookbinding, packaging, woodworking, adhesion of fibers, etc. In wet adhesive and hot melt adhesive applications, it has excellent blocking resistance after coating, and in rewetting adhesive applications it has excellent storage stability in the aqueous solution state (blocking resistance after long-term storage. There is no decrease in sex), which is very useful.

[0019]

[Operation] Since the adhesive of the present invention uses a specific modified PVA-based resin, it has excellent blocking resistance, and also has excellent storage stability in an adhesive in the form of an aqueous solution. It is very useful in various adhesive applications such as mold adhesives, rewetting adhesives and hot melt adhesives.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, “%” and “part” mean on a weight basis unless otherwise specified. (Production of modified PVA resin) 500 parts of maleic anhydride,
65.9 parts of diisobutylamine was charged into a flask, and the reaction was carried out at 60 ° C. for 2 hours while stirring. After completion of the reaction, the reaction product was recrystallized to obtain the compound represented by Chemical formula 4.

Embedded image R ₀ is shown in Chemical formula 5.

Embedded image The yield was 95%.

A polymerization vessel equipped with a reflux condenser, a dropping funnel and a stirrer was charged with 1000 parts of vinyl acetate and 1500 parts of methanol and the temperature was raised under a nitrogen stream while stirring to 62 ° C.
In, a solution of 0.6 parts of azobisisobutyronitrile dissolved in 19.4 parts of methanol was added to initiate polymerization. Polymerization was performed while continuously adding dropwise 272 parts of a methanol solution containing 27.2 parts of the compound N, N-diisobutylmaleic acid monoamide obtained above from the polymerization initiation point over 5 hours while the vinyl acetate had a polymerization rate of 50. %
The polymerization was terminated when Then, the unreacted vinyl acetate monomer was removed out of the system by a method of blowing methanol vapor to obtain a methanol solution of the copolymer. Then
The solution was diluted with methanol to adjust the concentration to 30%, charged into a kneader, and neutralized by adding sodium hydroxide while keeping the solution temperature at 35 ° C. To this, sodium hydroxide was further added in an amount of 30 mmol with respect to the vinyl acetate unit in the polymer and kneaded. As the saponification reaction proceeded, a saponified product was deposited and finally became a particulate form. Generated modified PVA
The resin was filtered, washed well with methanol and dried in a hot air drier to obtain the desired product. The resulting modified PVA-based resin was extracted and washed with methanol using a Soxhlet extractor, and the degree of modification with diisobutyl maleic acid monoamide was ¹ H.
As a result of analysis by -NMR, the degree of modification was 2.0 mol%. The saponification degree of the modified PVA-based resin was 90 mol% when analyzed by quantifying the amount of alkali consumption required for hydrolysis of the residual vinyl acetate unit. The viscosity of the 4% aqueous solution of this modified PVA-based resin measured by a B-type viscometer is
At 5.1 cps / 20 ° C., the degree of polymerization was 500.

Example 1 A 30% aqueous solution of the above-mentioned modified PVA-based resin was prepared, coated on a surface of high-quality paper with a bar coater to a dry thickness of about 10 μm, and dried. Two sheets of the coated paper were prepared and stacked so that the coated surface and the other surface were in contact with each other and 10 g /
A load of cm ² was applied, the mixture was allowed to stand at 20 ° C. and 65% RH for 5 hours, the blocking property (I) was examined, and evaluated as follows. ○ --- There is no blocking at all. (Triangle | delta) -There is some blocking and there is resistance at the time of peeling. × −−− Blocking is remarkable and material destruction occurs during peeling.

Furthermore, after the above PVA aqueous solution was allowed to stand at 40 ° C. for 1 month, the blocking property (II) was examined in the same manner and evaluated in the same manner. In addition, the above-mentioned modified PVA-based resin 1
00 parts, 25 parts of glycerin, 35 parts of terpene phenolic resin, and 40 parts of 12-oxyoctadecanoic acid were charged into a melting can and melt-mixed at 170 ° C to obtain a hot melt adhesive. The adhesive was heated and melted to prepare a sample having a thickness of 100 μm, two samples were stacked, a load of 100 g / cm ² was applied, and the sample was left at 20 ° C. and 65% RH for 5 hours,
The blocking property (III) was examined and evaluated in the same manner as above.

Examples 2 to 7 and Comparative Examples 1 to 6 Ethylenically unsaturated dicarboxylic acid monoamides were synthesized under the components and conditions shown in Table 1 and various ethylenically unsaturated dicarboxylic acid monoamides and vinyl acetate were obtained. The copolymerization of the above (modified PVA with the components and charging amounts shown in Table 2)
Copolymerization with vinyl acetate (in Comparative Example 6, no modifying monomer was added) and saponification were carried out in the same manner as in (Production of resin) to produce various modified PVA resins shown in Table 2. Then, the blocking states (I) to (III) were evaluated in the same manner as in Example 1 using the PVA-based resin. Table 4 shows the evaluation results of the examples and the comparative examples.

[0025]

[Table 1] Synthetic conditions of ethylenically unsaturated dicarboxylic acid monoamide Synthetic monoamic acid amine Temperature temperature Yield (part) (part) (° C) (hr) (%) Di-BMMAm Diisobutylamine maleic acid 60 2 95 Di- BIMAm Itaconic anhydride Diisobutylamine 60 295 Di-AMMAm Maleic anhydride Diisoamylamine 60 2 97 D-EHMMAm Maleic anhydride Di (2-ethylhexyl) amine 60 2 92 Dn-DMMAm Maleic anhydride Di-n-propylamine 60 2 95 N-n-OMMAm n-octylamine maleic anhydride 60 290 Note) Abbreviations are as follows. D-i-BMMAm; N, N-diisobutyl maleic acid monoamide D-i-BIMAm; N, N-diisobutylitaconic acid monoamide D-i-AMMAm; N, N-diisoamyl maleic acid monoamide D-EHMMAm; N, N -Di (2 ethylhexyl) maleic acid monoamide D-n-DMMAm; N, N-di-n-propyl maleic acid monoamide N-n-OMMAm; N-n-octyl maleic acid monoamide

[0026]

[Table 2] Type of monomer copolymerized with vinyl acetate, charged amount and polymerization rate (A) Monomer Polymerized rate type Charged amount (mol%) (%) Example 1 D-i-BMMAm 2. 0 50 〃 2 D-i-BMMAm 0.5 60 〃 3 D-i-BMMAm 8.0 47 〃 4 D-i-BIMAm 2.0 50 50 〃 5 D-i-AMMAm 2.0 55 〃 6 D- EHMMAm 2.0 45 〃 7 D-BMMAm 2.0 50 Comparative Example 1 D-n-DMMAm 2.4 53 〃 2 N-n-OMMAm 2.5 52 〃 3 MRM 3.0 55 〃 4 AMPS 2.0 55 〃 5 3M 2.0 60 〃 6 --- 87

Note) The charged amount represents the charged mole fraction (mol%) of the monomer (A) with respect to the total charged amount of the monomers. Abbreviations are as follows. D-i-BMMAm; N, N-diisobutyl maleic acid monoamide D-i-BIMAm; N, N-diisobutylitaconic acid monoamide D-i-AMMAm; N, N-diisoamyl maleic acid monoamide D-EHMMAm; N, N -Di (2 ethylhexyl) maleic acid monoamide D-n-DMMAm; N, N-di-n-propyl maleic acid monoamide N-n-OMMAm; N-n-octyl maleic acid monoamide 3M; monomethyl maleate MRM; mono ( Diisopropylmethyl) malate AMPS; N-sulfoisobutylene acrylamide sodium

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

Since the adhesive of the present invention uses a specific modified PVA-based resin, it has excellent blocking resistance, and further has excellent storage stability in an aqueous adhesive.
It is useful in various adhesive applications such as general aqueous solution adhesives, rewetting adhesives, hot melt adhesives, pressure-sensitive adhesives, and quick-setting (honeymoon) adhesives, especially rewetting adhesives and hot melt adhesives. Very useful for

Claims (1)

[Claims] 1. A polyvinyl alcohol-based polymer containing the ethylenically unsaturated dicarboxylic acid monoamide (A) represented by the following chemical formula 1 as a copolymerization component in an amount of 0.1 to 20 mol%, wherein the ethylenically unsaturated dicarboxylic acid is An adhesive characterized in that the amide component of the monoamide (A) contains a polyvinyl alcohol-based resin represented by the following chemical formula 1 as a main component. Embedded image Here, R ₀ is shown in Chemical formula 2. Embedded image (However, n is 1 to 3, R _{1 to} R ₃ are each hydrogen or an alkyl group or an aryl group, and two or more are not hydrogen at the same time, and the total number of carbon atoms of R _{1 to} R ₃ is 4 That is all.)