JP2847606B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition which is water-based and excellent in safety and which has good product stability, adhesiveness, heat resistance and water resistance. More specifically, vinyl chloride resin and wood, nylon, polyester The present invention relates to a water-based adhesive composition having excellent adhesiveness to various substrates such as synthetic fibers and films, and useful as an adhesive for lamination.

[0002]

2. Description of the Related Art As a conventional aqueous adhesive composition of a vinyl chloride resin and various base materials, an aqueous latex such as a vinyl acetate latex, an acrylate latex, or a polyvinyl chloride latex has a normal adhesive strength and a low price. It has been mainly used from the point of view.

[0003] However, while these aqueous adhesive compositions are excellent in normal-state adhesive strength, the adhesive strength under high temperature atmosphere, high humidity, and wet conditions tends to be extremely reduced. When exposed for a long time or when a load is applied, there are disadvantages such as peeling of the adhesive surface.

[0004] As an attempt to improve the heat resistance and water resistance, for example, JP-B-63-33518 and JP-A-3-111471 disclose the use of a vinyl acetate type latex and a carboxyl group-containing polyester type aqueous polyurethane resin. Aqueous adhesive compositions have been proposed in which various cross-linking agents such as aziridine-based compounds and carbodiimide-based compounds are used in combination, but their water resistance is improved, but their heat resistance is insufficient and their uses are limited. There was a problem that it was done.

[0005] Further, since the carboxyl group-containing polyester-type water-based polyurethane resin has poor hydrolysis resistance, the product stability of the resulting water-based adhesive composition obtained is insufficient.

[0006]

The problem to be solved by the present invention is to provide an aqueous system which is excellent in safety and good in product stability, and in which vinyl chloride resin and synthetic fibers and films such as wood, nylon and polyester are used. It is an object of the present invention to provide an adhesive composition which is excellent in adhesiveness to various base materials such as PVC, plywood, razor, and laminating adhesive having excellent heat resistance and water resistance.

[0007]

Means for Solving the Problems] Specifically, the subject matter of the present invention, the urethane prepolymer - anti salt-forming agent and a chain extender
Becomes an aqueous polyurethane resin obtained by response, and vinyl acetate-based latex, a blend of an organic polyisocyanate crosslinking agent having two or more in one molecule of the isocyanate group (hereinafter referred to as organic polyisocyanate crosslinking agent) ,
The weight ratio of the aqueous polyurethane resin / vinyl acetate latex (in terms of solid content) is 7/93 to 50/50.
The free NCO of the organic polyisocyanate crosslinking agent
(%) Is 5 to 50% by weight, and the compounding amount of the organic polyisocyanate-based crosslinking agent is 1 to 15% by weight based on the total amount (solid content conversion) of the aqueous polyurethane resin and the vinyl acetate-based latex. In the adhesive composition,

[0008] The urethane prepolymer is (a) an average molecular weight of 500 to 500 represented by the following general formula (1) or (2):
2 in a molecule of 5,000 (weight average molecular weight, the same applies hereinafter)
A polyester polyol compound having at least two hydroxyl groups (hereinafter abbreviated as a polyester polyol compound represented by the general formula (1) or (2)), and (b) an average molecular weight of 200
(Weight average molecular weight, hereinafter the same) Low molecular weight hydroxyl group-containing compound having two or more hydroxyl groups in the following molecules (hereinafter abbreviated as compound (b)), (c) having two or more isocyanate groups in the molecule Organic polyisocyanate compound, and (d) taurine, methyltaurine and butyltaurine
Consisting of at least one compound selected from the group consisting of (hereinafter abbreviated as compound (d)) and having an average active hydrogen concentration of 100 to 500 (KOH mg / g) and NCO
An adhesive composition comprising: a urethane prepolymer having an / active hydrogen group ratio of 1.0 to 1.2, wherein the salt-forming agent is a salt-forming agent corresponding to the compound (d).

[0009]

Embedded image

[0010]

Embedded image (In the formula, R and R ′ each represent a hydrocarbon group having 4 to 10 carbon atoms. N is an arbitrary number corresponding to the molecular weight.)

The main items relating to the configuration of the present invention will be described below. [Aqueous polyurethane resin] Examples of the aqueous polyurethane resin include compounds prepared from various components as described above.

(Urethane prepolymer) (a) Polyester polyol compound represented by formula (1) or (2); Polyester polyol represented by formula (1) or (2) used in the present invention Examples of the compound include a compound synthesized from a polyvalent hydroxyl group-containing compound having 4 to 10 carbon atoms and a polybasic acid, a ring-opening polymer of a lactone, the polyvalent hydroxyl group-containing compound represented by the general formula (2), and phosgene. And polycarbonate carbonate synthesized from dimethyl carbonatediol.

Examples of the compound containing a polyvalent hydroxyl group include, for example,
4-butanediol, 1,3-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2- Methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, trimethylolpropane and the like can be mentioned.

When the polyvalent hydroxyl group-containing compound has less than 4 carbon atoms, the resulting adhesive composition cannot suppress the migration of the plasticizer in the vinyl chloride film, and can only obtain a composition having poor heat resistance. Further, the compound having a polyvalent hydroxyl group has 10 carbon atoms.
When the value exceeds, the obtained adhesive composition has insufficient cohesive force, and only those having poor adhesiveness and heat resistance can be obtained.

Examples of the polybasic acids include polybasic acids such as adipic acid, azelaic acid, sebacic acid, terephthalic acid, succinic anhydride, maleic anhydride, fumaric acid, and trimellitic anhydride. Aliphatic polybasic acids such as azelaic acid and sebacic acid are preferred in terms of adhesiveness and product stability.

Next, as the lactones, caprolactone,
Valerolactone and the like.

The polyester polyol compound represented by the general formula (1) or (2) used in the present invention needs to have an average molecular weight of 500 to 5,000 as described above. When the average molecular weight is less than 500, the adhesive composition obtained by blending the obtained aqueous urethane resin has only poor adhesiveness. The average molecular weight is 5,000
If it exceeds 0, not only is it difficult to produce an aqueous urethane resin, but the resulting aqueous urethane resin crystallizes at room temperature, so that a satisfactory adhesive composition cannot be obtained.

(B) Compound (b): The compound (b) used in the present invention is a low molecular weight hydroxyl group-containing compound having two or more hydroxyl groups in the molecule, for example, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol,
3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, trimethylolpropane, glycerin,
Pentaerythritol and the like.

The compound (b) must have an average molecular weight of 200 or less as described above. Average molecular weight 2
If it exceeds 00, the resulting adhesive composition will have insufficient cohesive strength and poor adhesion and heat resistance.

(C) Organic polyisocyanate compound: Examples of the organic polyisocyanate compound used in the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthylene diisocyanate. G, isophorone diisocyanate
DOO, hexamethylene diisocyanate - DOO, hydrogenated diphenylmethane diisocyanate - DOO, hydrogenated toluene diisocyanate, tetramethyl xylylene diisocyanate -
And all conventionally used aromatic, aliphatic, and alicyclic isocyanates, such as bullets and isocyanurates of these isocyanates, alone or in combination. Tolylene diisocyanate and diphenylmethane diisocyanate are preferred from the viewpoint of low cost and heat resistance.

(D) Compound (d): Compound (d) used in the present invention includes taurine, methyltaurine and
At least one member selected from the group consisting of tiltaurine
Compound.

(E) Average active hydrogen concentration and NCO / active hydrogen group ratio: The average active hydrogen concentration of the urethane prepolymer used in the present invention is 100 to 500 (KOH mg / mg).
g). Average active hydrogen concentration is 10
If it is less than 0, the resulting aqueous urethane resin will have insufficient cohesive strength, and the adhesive composition will also have poor heat resistance and water resistance. Further, when the average active hydrogen concentration exceeds 500, the obtained aqueous urethane resin has a very high cohesive force,
Since the glass transition temperature rises, the adhesive composition containing the water-based urethane resin is also inferior in flexibility and not only inadequate in terms of normal state adhesiveness, but also in particular, the low-temperature adhesive strength is extremely poor. .

The urethane prepolymer must have an NCO / active hydrogen group ratio of 1.0 to 1.2. N
When the CO / active hydrogen group ratio is out of the range of 1.0 to 1.2, the molecular weight of the obtained aqueous urethane resin becomes small, and the adhesive composition becomes inferior in heat resistance and water resistance.

(Salt-forming agent corresponding to compound (d)) Examples of the salt-forming agent corresponding to compound (d) include monovalent metal hydroxides such as sodium hydroxide and potassium hydroxide, ammonia, and the like. And tertiary amine compounds such as trimethylamine and triethylamine.

(Chain extender) Examples of the chain extender used in the present invention include ethylenediamine, propylenediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, xylylenediamine, diphenylmethanediamine. , A compound having two or more amino groups such as hydrogenated diphenylmethanediamine, or water.

(Preparation of Aqueous Urethane Resin) The aqueous urethane resin of the present invention comprises a polyester polyol compound represented by the general formula (1) or (2), a compound (b), an organic polyisocyanate compound and a compound (d). The resulting urethane prepolymer is obtained by emulsifying in water by a known method using a salt-forming agent corresponding to compound (d), and further extending the chain with a chain extender.

In order to facilitate the emulsification, an organic solvent which does not react with the isocyanate group may be added, if necessary, at the urethane prepolymer reaction stage or after the completion of the reaction. It is also possible to obtain a solvent-free aqueous urethane resin by distilling off the organic solvent under reduced pressure, if necessary.Moreover, at the time of emulsification, an anion, a cation, and a surfactant such as a nonionic surfactant are supplementarily added. It is also possible to facilitate the emulsification.

[Vinyl acetate latex] The vinyl acetate latex used in the present invention includes vinyl acetate homopolymer, vinyl acetate-ethylene copolymer, vinyl acetate
Ethylene-acrylate copolymer, vinyl acetate-
Examples thereof include an ethylene-methacrylic acid ester copolymer and a vinyl acetate-ethylene-vinyl chloride copolymer. Among them, a vinyl acetate-ethylene copolymer is preferable in terms of adhesiveness and heat resistance.

[Organic polyisocyanate crosslinking agent] Examples of the organic polyisocyanate crosslinking agent having two or more isocyanate groups in one molecule include tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate. -, Naphthylene diisocyanate,
Isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate
DOO, hydrogenated toluene diisocyanate, tetramethyl <br/> xylylene diisocyanate - DOO, and all aromatic which is commonly conventionally such as biuret product or an isocyanurate product of these isocyanates, aliphatic isocyanates And adducts of polyvalent hydroxyl group-containing compounds such as trimethylolpropane and the above-mentioned isocyanate compounds, alone or in admixture, and especially adducts of burettes and isocyanurates of aliphatic isocyanates with polyvalent hydroxyl-containing compounds. Are preferred in terms of workability, toxicity, water resistance, and heat resistance.

[Adhesive Composition] The adhesive composition of the present invention is obtained by mixing and mixing a predetermined amount of the above-mentioned aqueous polyurethane resin, vinyl acetate-based latex and organic polyisocyanate-based crosslinking agent.

As described above, the weight ratio of the aqueous polyurethane resin to the vinyl acetate latex (in terms of solid content) is as follows.
Water-based polyurethane resin / vinyl acetate-based latex = 7 /
93 to 50/50 . When the vinyl acetate-based latex is out of this range, an adhesive composition satisfying water resistance, heat resistance and price cannot be obtained.

Free N of organic polyisocyanate crosslinking agent
The CO% is 5 to 50% by weight, and when the free NCO% is less than 5% by weight, the obtained adhesive composition has poor water resistance.

The compounding amount of the organic polyisocyanate crosslinking agent is 1 to 15% by weight, preferably 5 to 10% by weight, based on the total amount (in terms of solid content) of the aqueous polyurethane resin and the vinyl acetate latex. . When the amount exceeds 15% by weight, the reaction with the active hydrogen compound becomes excessive, and the adhesiveness, water resistance and heat resistance are reduced. If the amount is less than 1% by weight, the adhesiveness, water resistance and heat resistance cannot be improved because the crosslink density is low even when reacted with an active hydrogen compound.

[Other Compounds / Additives] The composition of the present invention contains an extender, an antioxidant, a leveling agent, an antifoaming agent, a penetrant, a diluent, a film-forming auxiliary (such as xylene), and a thickener. It is possible to appropriately mix various additives such as an antifungal agent within a range that does not lower the performance in order to make the properties suitable for the purpose.

[Adhesion Method] The adhesion method of the adhesive composition of the present invention includes spray application, brush application, roll coater application,
After coating with a knife coater or the like, a method of laminating and drying and bonding various substrates can be used. Incidentally, if necessary, by performing processing such as weighting and heating, to improve the adhesive strength,
It is also possible to shorten the bonding time.

[0036]

[Function] Vinyl acetate-based latex has been conventionally used as an adhesive for PVC plywood, PVC leather, and laminating because of its excellent adhesive strength to vinyl chloride resin and low cost. Under a high-temperature atmosphere, a large amount of plasticizer migrates to the interface of the adhesive, so that the adhesive strength tends to be extremely reduced.
Further, the vinyl acetate-based latex contains a large amount of an emulsifier, and not only has high water absorption, but also has a tendency that the adhesive strength at the time of water absorption is extremely reduced.

However, the adhesive composition of the present invention, especially free N
By blending an organic polyisocyanate-based crosslinking agent having a CO% of 5 to 50% by weight with respect to the total amount (solid content conversion) of aqueous polyurethane and vinyl acetate-based latex, 1 to 15% by weight of vinyl chloride resin And wood or nylon,
Water-based adhesive composition useful as an adhesive for PVC plywood, PVC leather, laminating, which has dramatically improved adhesiveness, heat resistance, and especially water resistance to synthetic fibers such as polyester and various substrates such as films. Things can be provided.

The use of an organic polyisocyanate-based crosslinking agent allows the NCO group to be crosslinked with water, an adherend and a reactive group of an aqueous polyurethane or vinyl acetate latex, for example, an active hydrogen-containing compound (amine, alcohol). Therefore, it is considered that the adhesiveness, water resistance and heat resistance are excellent.

[0039]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3. In an acetone solvent, a urethane prepolymer is converted from a polyester polyol compound represented by the general formula (1) or (2), a compound (b), an organic polyisocyanate compound and a compound (d) to a salt corresponding to the compound (d). Emulsification in water by a known method by the use of a forming agent, and further removing the acetone solvent under reduced pressure from various milky white to transparent liquid aqueous polyurethane resins obtained by chain extension with a chain extender, various solvent-free types An aqueous urethane resin (solid content 40% by weight) was prepared. These are shown in Tables 1 and 2.

[0040]

[Table 1]

[0041]

[Table 2]

The abbreviations in Tables 1 and 2 indicate the following. Hereinafter, the same applies. (A): polyhexylene adipate (polyester polyol from 1,6-hexanediol and adipic acid; average molecular weight 2000);
(B): polybutylene adipate (polyester polyol from 1,4-butanediol and adipic acid; average molecular weight 2000); (c): polybutylene adipate (polyester polyol from 1,4-butanediol and adipic acid. Average) (Molecular weight 1000), (d): Polynonylene adipate (polyester polyol from 1,9-nonanediol and adipic acid, average molecular weight 200)
0), (e): polyethylene adipate (polyester polyol from ethylene glycol and adipic acid; average molecular weight 2000), (f): polytetramethylene glycol (ring-opened polymer of tetrahydrofuran; average molecular weight 2000) TDI: tri Diisocyanate (2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate = 80/20), MDI: diphenylmethane diisocyanate

Examples 1 to 19 and Comparative Examples 1 to 7 The various solvent-free aqueous urethane resins (solid content: 40% by weight) obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3 were mixed with vinyl acetate-ethylene. Polymer latex (Sumika Flex 4)
71. Sumitomo Chemical Co., Ltd. A predetermined amount of an organic polyisocyanate-based crosslinking agent and a predetermined amount of an organic polyisocyanate-based crosslinking agent are blended to prepare a water-based adhesive composition. An adhesion test with plywood (Lauan plywood; thickness 3.0 mm) was performed. The results of these tests are shown in Tables 3, 4, 5 and 6.

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

The abbreviations in Table 3, Table 4, Table 5, and Table 6 represent the following. Hereinafter, the same applies. TDI- adduct trimethylolpropane tolylene diisocyanate adduct HDI: hexamethylene diisocyanate HDI- isocyanurate: hexamethylene diisocyanate isocyanurate product (trimer) IPDI: isophorone diisocyanate TMXDI: tetramethylxylylene diisocyanate H ₁₂ MDI: dicyclohexylmethane diisocyanate PAPI -135: Polymethylene polyphenyl isocyanate (manufactured by Mitsubishi Kasei Dow) Bullet HDI: Bulleted hexamethylene diisocyanate

(Adhesion conditions) Laminating method: cold-pressure wet lamination method, coating amount: 100 g per square cm (using a bar coater), pressing condition: 0.1 kg per square cm, 20 ° C. × 60
Minutes, Curing time: 20 ° C x 5 days,

(Adhesion test method) (1) Normal adhesion: 180 ° peel test at 20 ° C. and 60% RH (tensile speed: 100 mm / min, unit kg / 2)
(2) Wet adhesive strength: 2 hours after immersion in hot water at 60 ° C. for 3 hours.
180 degree peel test in the state of being immersed in water of 0 ° C. for 30 minutes and wet (tensile speed: 100 mm / min, unit kg / 25 m)
m), (3) Heat-resistant creep at 60 ° C .: A static load of 500 g is applied to the end of a semi-rigid vinyl chloride sheet (sheet width 25 mm), and the peel length after 60 ° C. × 120 minutes at 180 ° angle is measured ( (Unit: mm / 60 minutes), (4) 80 ° C. heat creep: A 500 g static load is applied to the end of a semi-rigid vinyl chloride sheet (sheet width 25 mm), and peeling at 80 ° C. × 60 minutes at 180 ° angle. Measure the length (mm / 60 minutes),

Examples 20 to 21 Using the adhesive composition of Example 1, an adhesion test was conducted between a polyvinyl chloride sheet and a nylon fiber cloth, and between a polyvinyl chloride sheet and a polyester fiber cloth. Table 7 shows the test results. The bonding conditions and the like are the same as described above.

[0052]

[Table 7]

[0053]

The adhesive composition of the present invention is an aqueous adhesive composition which is excellent in safety in an aqueous system and has good product stability, adhesiveness, heat resistance and water resistance. It is useful as a plywood, a PVC leather, and an adhesive for lamination, which have excellent adhesiveness to various substrates such as synthetic fibers such as nylon, polyester, and polyester, and films.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09J 175/04-175/10 C09J 131/04 C08G 18/12

Claims (1)

(57) [Claims] 1. A water-based polyurethane resin obtained by reacting a urethane prepolymer, a salt-forming agent and a chain extender, a vinyl acetate-based latex, and an organic polyisocyanate-based crosslink having two or more isocyanate groups in one molecule. (Hereinafter referred to as an organic polyisocyanate-based crosslinking agent), and the weight ratio of the aqueous polyurethane resin / vinyl acetate-based latex (in terms of solid content) is 7/93.
50 to 50/50 , wherein the free NCO (%) of the organic polyisocyanate-based crosslinking agent is 5 to 50% by weight, and the blending amount of the organic polyisocyanate-based crosslinking agent is between the aqueous polyurethane resin and the vinyl acetate latex. Wherein the urethane prepolymer is (a) a weight- average molecular weight represented by the following general formula (1) or (2): 500-5,000
(B) a low molecular weight hydroxyl group-containing compound having two or more hydroxyl groups in a molecule having a weight average molecular weight of 200 or less, (c) a polyester polyol compound having two or more hydroxyl groups in a molecule, Organic polyisocyanate compound having isocyanate group, and (d) tauri
, Methyltaurine and butyltaurine
At least one selected compound (hereinafter, compound (d)
And the average active hydrogen concentration is 100 to 5
00 (KOH mg / g) and an urethane prepolymer having an NCO / active hydrogen group ratio of 1.0 to 1.2, wherein the salt-forming agent is a salt-forming agent corresponding to the compound (d). Adhesive composition. Embedded image Embedded image (In the formula, R and R ′ each represent a hydrocarbon group having 4 to 10 carbon atoms. N is an arbitrary number corresponding to the molecular weight.)