JP2002363525A - Aqueous adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous adhesive composition which is perfectly aqueous and is excellent, e.g. in resistances to boiling water and chemicals. SOLUTION: This aqueous adhesive composition contains an aqueous dispersion and a water-dispersible polyisocyanate composition which contains a polyisocyanate and an emulsifier prepared by reacting a polyisocyanate with an alkoxypolyalkylene ether glycol and a dialkanolamine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aqueous adhesive composition. In particular, the present invention relates to a water-based adhesive composition for lamination having excellent adhesion to a plastic film or a plastic film and a metal foil, paper or the like.

[0002]

2. Description of the Related Art In the field of lamination, a solvent-type urethane adhesive diluted with an organic solvent such as ethyl acetate or toluene has been mainly used. Although these solvent-type urethane adhesives exhibit high performance in terms of adhesiveness, heat resistance, water resistance, etc., they use a large amount of organic solvents, so they have safety problems, environmental pollution problems, and resource saving. It was not preferable from a point. On the other hand, in the field of extrusion lamination, aqueous polyethylene imine and butadiene rubber are used in addition to the solvent-type polyurethane adhesive. However, since these are diluted with a large amount of alcohol at the time of use, there is a problem in safety, and there is a problem in heat resistance and water resistance of the obtained lamination product. In order to solve these problems, a water-dispersible polyisocyanate using a reaction product of an aliphatic polyisocyanate such as a trimer of 1,6-hexamethylene diisocyanate and an alkoxypolyalkylene ether glycol as an emulsifier is used in aqueous, Alternatively, by using a water-dispersible polymer, for example, polyvinyl alcohol, an acrylic resin, a rubber-based latex, a urethane resin, or the like, it is intended to provide an adhesive that is completely water-based and has excellent heat resistance, water resistance, and the like. (Japanese Patent Laid-Open No. 61-29161)
3, Tokuhei 4-15270).

[0003]

However, even these water-based adhesives are insufficient in performance such as resistance to boiling water, chemical resistance, and film suitability.

[0004]

Means for Solving the Problems As a result of intensive studies to solve these problems, the present inventors have found that a water-dispersible polyisocyanate composition containing a specific emulsifier and a polyisocyanate, It has been found that when used in combination with a body, a water-based adhesive composition that is completely water-based and excellent in water resistance, heat resistance, boiling water resistance, chemical resistance, and the like can be obtained, and has completed the present invention. That is, the present invention provides a water-dispersible polyisocyanate composition containing an emulsifier and a polyisocyanate obtained by reacting an alkoxypolyalkylene ether glycol and a dialkanolamine with a polyisocyanate,
And an aqueous dispersion.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The emulsifier used in the present invention can be obtained by reacting a polyisocyanate with an alkoxypolyalkylene ether glycol and a dialkanolamine. Examples of the polyisocyanate include aliphatic diisocyanates such as tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.
1,3-cyclohexylene diisocyanate, 1,4-
Cyclohexylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate,
4,4'-dicyclohexylmethane diisocyanate,
Alicyclic diisocyanates such as 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate and 1,5-tetrahydronaphthalenediisocyanate;
-Tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3 Aromatic diisocyanates such as'-dimethyl-4,4'-biphenylene diisocyanate and 1,5-naphthalenediisocyanate, araliphatic diisocyanates such as xylylene diisocyanate and tetramethyl xylylene diisocyanate, 2,4,6-triisocyanate toluene, 2,4,4'-triisocyanate diphenyl ether, tri (isocyanate phenyl)
Triisocyanates such as methane and tri (isocyanatephenyl) thiophosphite; biuret-type polyisocyanates derived from 3 moles of diisocyanate and 1 mole of water; isocyanurate-type polyisocyanates formed by trimerization of diisocyanates; diphenylmethane Polymethylene polyphenyl polyisocyanate by-produced during the production of 4,4'-diisocyanate, and adduct-type polyisocyanate obtained by adding the above polyisocyanate to glycols, triols or polyester polyols, polyether polyols, and the like. Examples include polyisocyanates such as isocyanate prepolymers and mixtures thereof. Preferably, diisocyanates are used.

Examples of the alkoxypolyalkylene ether glycol include methoxy polymethylene ether glycol, ethoxy polymethylene ether glycol, methoxy polyethylene ether glycol, ethoxy polyethylene ether glycol, methoxy polybutylene ether glycol, ethoxy polybutylene ether glycol and the like. . The alkoxy polyalkylene ether glycol has an average molecular weight of 100 to 400.
0 is preferably used. Average molecular weight 400 ~
2000 is particularly preferably used. The average molecular weight of the alkoxypolyalkylene ether glycol is 10
If it is less than 0, the portion having a surfactant activity of the water-dispersible polyisocyanate composition is reduced, and the water-dispersibility may be deteriorated. If the molecular weight of the alkoxypolyalkylene ether glycol exceeds 4000, the water-dispersibility may be reduced. This is because the viscosity of the polyisocyanate composition becomes high, and the dispersibility in water may be deteriorated. Examples of the dialkanolamine include dimethanolamine, jetanolamine, dipropanolamine, diisopropanolamine, diethanolaniline, and the like.

The emulsifier used in the present invention can be obtained by reacting a polyisocyanate with an alkoxypolyalkylene ether glycol and a dialkanolamine. More specifically, an emulsifier is prepared by reacting a polyisocyanate and an alkoxypolyalkylene ether glycol with an isocyanate group. / Equivalent ratio of hydroxyl group is 3 to 30, preferably 10 to
After the reaction at 25, the unreacted polyisocyanate is removed, and then the equivalent ratio of dialkanolamine to isocyanate group / amino group is 0.5 to 2.0, preferably 0.1 to 2.0.
It is obtained by reacting at 8 to 1.2. The reaction between the polyisocyanate and the alkoxypolyalkylene ether glycol is performed at about 40 to 100 ° C. for about 2 to 24 hours. It is preferable to perform the reaction under a nitrogen atmosphere, and a solvent may be used. As the solvent, any solvent may be used as long as it is inert to an isocyanate group, and ethyl acetate,
Ester solvents such as butyl acetate and cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aromatic solvents such as benzene, toluene and xylene; and heterocyclic solvents such as N-methylpyrrolidone. . For the removal of unreacted polyisocyanate, a known method such as a distillation method and an extraction method is used.
Examples of the distillation method include a continuous distillation method, a batch distillation method, and a thin film distillation method. A thin film distillation method is preferably used. As the extraction method, liquid-liquid extraction such as continuous extraction or batch extraction is used, and a relatively low-polarity solvent such as hexane or acetate is used as an extraction solvent. The subsequent reaction with dialkanolamine is carried out at room temperature to about 120 ° C.
It is desirable to perform it in a nitrogen atmosphere. A solvent may be used in the same manner as described above. By combining the thus obtained emulsifier and polyisocyanate, a water-dispersible polyisocyanate composition can be obtained. In the water-dispersible polyisocyanate composition, the polyisocyanate used together with the emulsifier is the same as the polyisocyanate used in the production of the emulsifier. Preferably, an aliphatic polyisocyanate is used.

The water-dispersible polyisocyanate composition of the present invention comprises an emulsifier and a polyisocyanate in an equivalent ratio of active hydrogen groups in the emulsifier to isocyanate groups in the polyisocyanate of 1 to 70, preferably 2 to 50. Although they are contained, they may be reacted. When the reaction is carried out, the reaction is carried out at room temperature to about 120 ° C. for about 1 to 24 hours. The average number of functional groups in the obtained water-dispersible polyisocyaniate composition is 2 to 5, preferably 2.5 to 4,
The isocyanate group content is 3 to 50% by weight, preferably 5 to 30% by weight. If the average number of functional groups of the water-dispersible polyisocyanate composition is less than 2, dispersibility in water as an aqueous adhesive composition may be poor in water resistance,
On the other hand, if it exceeds 5, the dispersibility in water of the water-dispersible polyisocyanate composition may deteriorate. If the isocyanate group content is less than 3% by weight, dispersibility in water and water resistance as an aqueous adhesive composition may be poor, and if it exceeds 50% by weight, the polyisocyanate composition in water may be dispersed in water. This is because the property may be deteriorated. The aqueous dispersion used in the aqueous adhesive composition of the present invention together with the water-dispersible polyisocyanate composition contains a water-soluble substance and an aqueous emulsion. Examples of the water-soluble substance include polyvinyl alcohol, a water-soluble ethylene-vinyl acetate copolymer, polyethylene oxide,
Examples include a water-soluble acrylic resin, a water-soluble epoxy resin, a water-soluble cellulose derivative, a water-soluble polyester, and a water-soluble lignin derivative.

[0009] The aqueous emulsion includes all so-called latexes and emulsions. For example, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, chloroprene latex, rubber latex such as polybutadiene latex, polyacrylate latex, polyvinylidene chloride latex , Polybutadiene latex, or those obtained by carboxyl-modifying these latexes, and further include polyvinyl chloride emulsion, urethane acrylic emulsion, silicone acrylic emulsion, vinyl acetate acrylic emulsion, polyurethane emulsion, acrylic emulsion, polyester emulsion and the like. . These aqueous dispersions preferably have a functional group capable of reacting with an isocyanate group, and an anionic aqueous emulsion is suitably used. The anionic aqueous emulsion has a carboxyl group, an organic acid group such as a sulfonic acid group in an emulsion resin, and forms a salt with a basic substance such as an amine or an alkali metal and is dispersed, and
The emulsion resin has a functional group capable of reacting with an isocyanate group such as a hydroxyl group, an amino group and a carboxyl group. For example, an anionic polyester emulsion, an anionic polyurethane emulsion and the like can be mentioned.

The aqueous adhesive composition of the present invention comprises a water-dispersible polyisocyanate composition and an aqueous dispersion, wherein the weight ratio of the aqueous dispersion to the water-dispersible polyisocyanate composition is 30 to 0.2. And diluted with water to an appropriate concentration. Further, various additives may be added. Examples of the additives include tackifiers such as rosin ester emulsion, terpene resin emulsion, petroleum resin emulsion, aminosilane, epoxysilane, silane coupling agent such as acrylsilane, carboxymethyl cellulose, thickener such as polyvinylpyrrolidone, silica Fillers such as talc, mica, calcium carbonate, carbon black, etc., crosslinking agents such as carbodiimide, epoxy resin, lubricants such as stearic acid and zinc stearate, catalysts such as tertiary amines, metal salts of organic acids, etc. Is mentioned. Also, after bonding,
Even at room temperature, it exhibits sufficient boiling water resistance, chemical resistance, etc.,
By heating and aging to an appropriate temperature, it is possible to reduce the time required for developing boiling water resistance, chemical resistance and the like.

The aqueous adhesive composition of the present invention can be used in various fields such as adhesion of polyolefin materials, adhesion of materials for electrostatic flocking, adhesion of rubber products and synthetic resin products, and is mainly used in the field of lamination. It is preferably used. For example, in extrusion lamination, 0.1 ~
It was used so that the coating amount was 2.0 g / m ² ,
In dry lamination, it is used so that the coating amount is 2.0 to 4.5 g / m ² . These are useful in industrial material applications, food packaging applications, and the like.

[0012]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
Parts and% in Examples are parts by weight and% by weight, respectively.
It is shown. Example 1 (1) 225 parts of methoxypolyethylene ether glycol having an average molecular weight of 550 and 871 parts of 1,6-hexamethylene diisocyanate were placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube. The reaction was carried out at 70 ° C. for 6 hours in an atmosphere. The obtained reaction solution was applied to a thin film distillation apparatus to remove unreacted 1,6-hexamethylene diisocyanate, thereby obtaining a monoisocyanate compound having methoxypolyethylene ether glycol having an average molecular weight of 550. Next, 37 parts of diethanolamine is placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, and the reaction temperature of the monoisocyanate compound does not exceed 70 ° C. while cooling under air in a nitrogen atmosphere while air-cooling. And slowly dropped. After the completion of the dropwise addition, the mixture was stirred at 70 ° C. for about 1 hour in a nitrogen atmosphere, and it was confirmed that the isocyanate group had disappeared. Further, 42 parts of the emulsifier (B-1) and Takenate D-17 were placed in a four-necked flask equipped with a stirrer, thermometer, reflux tube and nitrogen inlet tube.
358 parts of 0HN (Takeda Pharmaceutical Co., Ltd .: 1,6-hexamethylene diisocyanate trimer) was added thereto, and the mixture was stirred at 70 ° C. for 6 hours under a nitrogen atmosphere to obtain a water-dispersible polyisocyanate composition (C -1) obtained. This water-dispersible polyisocyanate composition (C-1) had an isocyanate group content of 19.3% by weight and a viscosity of 2000 cps.

(2) Using acetone as a solvent, a polyester polyol having an average molecular weight of 2500 composed of dimethylolpropionic acid, isophthalic acid, sebacic acid, neopentyl glycol and ethylene glycol as a polyiol component, and tolylene diisocyanate and water as a polyisocyanate component. A mixture of the added xylylene diisocyanate is reacted at 50 ° C. for 6 hours in a nitrogen atmosphere at a ratio of an isocyanate group / hydroxyl group equivalent of 1.6 to obtain a polyurethane prepolymer containing a carboxyl group in the molecule. Was. This polyurethane prepolymer is dispersed in water by gradually adding it with stirring to water containing isopropanolamine having an amino group equivalent to a carboxyl group in the polyurethane prepolymer, and then adding hydrazine to react with the isocyanate group. Anionic polyurethane emulsion (A-1) having a solid content of 30% by weight and containing almost no solvent by elongating the chain and further distilling off acetone.
I got (3) The water-dispersible polyisocyanate composition (C-1) obtained in (1) and (2) and the anionic polyurethane emulsion (A-1) are sufficiently stirred and mixed at a weight ratio of 1/1, By further adding water, an aqueous adhesive composition having a resin concentration of 7% by weight was prepared. This was extruded and laminated, and the adhesive strength between the films, and the adhesive strength of the sealed portion of the laminated film subjected to human sealing at 160 ° C. for 0.6 seconds and 1.5 kgf were measured. In the test for boiling water resistance, a pouch was prepared by sealing under the above conditions, and the weight ratio of ketchup / oil / vinegar was 1/1/1.
, And the pouch was immersed in hot water at 90 ° C. for 1 hour, and then the adhesive strength was measured. The adhesive performance is shown in [Table 1].

[Table 1] Film configuration 1. Nylon film (15μ) / adhesive / extruded polyethylene (15μ) / low density polyethylene film (25μ) 2. polyester film (12μ) / adhesive / extruded polyethylene (15μ) / low density polyethylene film (25μ) Aluminum foil (30μ) / adhesive / extruded polyethylene (30μ) Note) *: Exfoliation between extruded polyethylene / low-density polyethylene PC: Extruded polyethylene cut material: Laminated film cut

Example 2 (1) 4 equipped with a stirrer, thermometer, reflux tube, and nitrogen inlet tube
100 parts of methoxypolyethylene ether glycol having an average molecular weight of 1000 and 168 parts of 1.6-hexamethylene diisocyanate were placed in a one-necked flask, and reacted at 70 ° C. under a nitrogen atmosphere until the isocyanate group content reached 29.8% by weight. The obtained reaction solution was applied to a thin-film distillation apparatus to remove unreacted 1,6-hexamethylene diisocyanate, thereby obtaining a monoisocyanate compound having methoxypolyethylene ether glycol having an average molecular weight of 1,000. Next, diethanolamine 178. was placed in a four-necked flask equipped with a stirrer, thermometer, reflux tube, and nitrogen inlet tube.
Eight parts were added, and 950 parts of the above monoisocyanate compound was gradually added dropwise while air cooling under a nitrogen atmosphere so that the reaction temperature did not exceed 70 ° C. After completion of the dropwise addition, the mixture was stirred at 70 ° C. for about 1 hour under a nitrogen atmosphere, and it was confirmed that the isocyanate group had disappeared. Thus, an emulsifier (B-2) was obtained. Further, in a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, 63.7 parts of emulsifier (B-2) and Takenate D-170HN (1,6-hexa manufactured by Takeda Pharmaceutical Co., Ltd.) 270.0 parts of a methylene diisocyanate trimer) was added, and the mixture was stirred at 70 ° C. under a nitrogen atmosphere. When the isocyanate group content reached 17.1% by weight, the water-dispersible polyisocyanate composition ( C-2) was obtained. This water-dispersed polyisocyanate composition (C-2)
It is a high viscosity white liquid at 25 ° C. and has a viscosity of 300
It was 0 cps. (2) Using acetone as a solvent, a polyol component is a polyester polyol having an average molecular weight of 1000 consisting of dimethylolpropionic acid, adipic acid, 2-ethylhexanol, neopentyl glycol and 1,6-hexanediol, and a tetramethyl isocyanate component is a polyisocyanate component. Using xylylene diisocyanate, isocyanate group /
Under an atmosphere of nitrogen at a ratio where the equivalent ratio of hydroxyl groups becomes 1.4
By reacting at 6 ° C. for 6 hours, a polyurethane prepolymer containing a carboxyl group in the molecule was obtained. This polyurethane prepolymer is dispersed in water by gradually adding it with stirring to water containing triethylamine having an amino group equivalent to a carboxyl group in the polyurethane prepolymer, and then dispersing in 2- (2-aminoethylamino). ) The chain was extended by adding ethanol and reacting with an isocyanate group, and the acetone was distilled off to obtain an anionic polyurethane emulsion (A-2) having a solid content of 30% by weight and containing almost no solvent.

(3) The water-dispersible polyisocyanate composition (C-2) obtained in (1) and (2) and the anionic polyurethane emulsion (A-2) are sufficiently stirred at a weight ratio of 5/1, Mix and add water to make the resin concentration 30
A weight percent aqueous adhesive composition was prepared. This was dry-laminated, and the adhesive strength between the films, and the adhesive strength of the sealed portion of the laminated film heat-sealed at 180 ° C. for 1.0 second and 1.0 kgf were measured. In the test for boiling water resistance, a pouch was prepared by sealing under the above conditions, a mixture having a weight ratio of water / oil / vinegar of 1/1/1 was put in the pouch, and the pouch was heated at 100 ° C. with hot water. This was carried out by immersing the sample for 30 minutes in the sample, and then measuring the adhesive strength. The adhesion is shown in [Table 2].

[Table 2] Film configuration Nylon film (15μ) / adhesive / low density polyethylene film (60μ)

[0016]

The water-based adhesive composition according to the present invention is a completely aqueous system using no organic solvent, does not pollute the environment during use, and is excellent in boiling water resistance, chemical resistance, film suitability, etc. It demonstrates its performance.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4J034 BA08 CA04 CA13 CB04 CC02 CC08 CC12 CC61 CC65 DA01 DB04 DB07 DG03 DG05 HA01 HA06 HA07 HA08 HB07 HB08 HB12 HC03 HC12 HC13 HC17 HC22 HC35 HC46 HC52 HC54 HC61 HC63 HC64 HC67 HC68 HC70 HC71 HC73 JA02 JA14 RA17 4J040 EF072 EF132 EF281 EF282 JA03 NA08

Claims (9)

[Claims] 1. A water-dispersible polyisocyanate composition comprising an emulsifier obtained by reacting a polyisocyanate with an alkoxypolyalkylene ether glycol and a dialkanolamine, and a polyisocyanate, and an aqueous dispersion. An aqueous adhesive composition comprising: 2. After the emulsifier reacts the polyisocyanate with the alkoxypolyalkylene ether glycol,
The aqueous adhesive composition according to claim 1, which is obtained by removing unreacted polyisocyanate and then reacting with a dialkanolamine. 3. The aqueous adhesive composition according to claim 1, wherein the polyisocyanate is a diisocyanate. 4. The aqueous adhesive composition according to claim 1, wherein the average molecular weight of the alkoxypolyalkylene ether glycol is from 400 to 2,000. 5. The aqueous adhesive composition according to claim 1, wherein the polyisocyanate is an aliphatic polyisocyanate. 6. The water-dispersible polyisocyanate composition has an isocyanate group content of 3 to 50% by weight.
The aqueous adhesive composition as described in the above. 7. The aqueous adhesive composition according to claim 1, wherein the aqueous dispersion is a latex or an emulsion. 8. The aqueous adhesive composition according to claim 1, wherein the aqueous dispersion is an anionic urethane emulsion. 9. A lamination film bonded with the aqueous adhesive composition according to claim 1.