KR100687600B1 - Urethane adhesives composition - Google Patents

Abstract

The present invention relates to a moisture-curable urethane adhesive composition that can be used to adhesively seal windshields of automobiles, wherein the urethane initial polymer obtained by reacting a mixture of polyols with an isocyanate compound and an isocyanate group / hydroxy group equivalent ratio of 1.0 A) 100 parts by weight; And 1 to 5 parts by weight of a urethane initial polymer (B) obtained by reacting a polyester polyol having a hydroxyl value of 20 to 40 with an equivalent ratio of hexamethylene diisocyanate and an isocyanate group / hydroxy group to 1 to 5, which is excellent. It has the advantage of having a final bond strength and a good initial bond strength even with relatively small usage.

Description

Moisture Curing Type Urethane Adhesives

The present invention relates to moisture curable urethane adhesive compositions, and more particularly to adhesives useful for adhesive sealing of windshields in automobiles.

Conventionally, in order to prevent sagging during adhesion of automotive windshields, a process of fixing the glass using a fixing device, curing and drying the adhesive, and then removing the fixing device has been necessary.

However, in recent years, there has been known a technique to prevent sagging of glass by high viscosity of the adhesive, or to impart initial adhesion strength by dropping and solidifying the temperature by using a molten polymer to prevent sagging of glass.

For example, Japanese Patent Application Laid-open No. Hei 2-32189 discloses a moisture-curable hot melt sealant which uses a polyether polyol together with a polyester polyol, and is mainly composed of a polyether polyol-based urethane polymer.

In addition, Japanese Patent Application Laid-open No. Hei 6-88067 discloses that a sealant mixture comprising a mixture of a polyether polyol-based urethane polymer and an ester compound having a melting point of 30 ° C to 100 ° C may exhibit high initial structural strength.

In addition, Japanese Patent Application Laid-open No. Hei 5-171035 discloses a urethane initial polymer mixed with a polyether polyol or polyester polyol and a urethane compound containing isocyanate, and a moisture including a monoalcohol added to mask free isocyanate groups in the initial polymer. A curable urethane sealant composition is disclosed.

On the other hand, Korean Patent Publication No. 1996-022919 is urethane initial polymer (A) obtained by using a polyether diol and polyether triol; A polyurethane compound (B) obtained by reacting a mixture of a polyester polyol and a polypropylene ether polyol with an isocyanate and then adding mono alcohol in an equivalent ratio of hydroxyl groups / isocyanate groups of less than 0.9; a polyurethane compound (B) A moisture curable urethane adhesive composition is disclosed in which the amount is 1 to 20 parts by weight per 100 parts by weight of the urethane initial polymer (A). In this adhesive composition, the urethane initial polymer (A) provides the final bond strength of the adhesive, and the polyurethane compound (B) has a function of imparting the necessary adhesive force at the beginning of the adhesion. Specifically, the polyurethane compound (B) is used in an amount of 1 to 20 parts by weight per 100 parts by weight of the urethane initial polymer (A), and the polyurethane compound (B) is used in an equivalent ratio of hydroxy groups / isocyanate groups of less than 0.9. Mono alcohol is added to mask free isocyanates.

However, the above composition did not have sufficient initial adhesion even though the amount of the polyurethane compound (B) was used in a large amount of 1 to 20 parts by weight, and those including the masked isocyanate material had the final bond strength and elasticity required in the moisture curing product. Had not had a downside.

Accordingly, the present invention has developed a urethane initial polymer having excellent final bond strength by the presence of free isocyanate without masking with mono alcohol or the like as in the prior art, and has an excellent crystallinity even if the content of the urethane initial polymer is small. The present invention has been completed by knowing that even in a hardened state, it has sufficient initial adhesion to secure the vehicle windshield without sagging.

Accordingly, it is an object of the present invention to provide a moisture curable urethane adhesive composition having excellent initial adhesive strength and excellent final bonding strength and elasticity.

The moisture-curable urethane adhesive composition of the present invention for achieving the above object is 100 parts by weight of the urethane initial polymer (A) obtained by reacting a mixture of polyols with an isocyanate compound and an isocyanate group / hydroxy group equivalent ratio of 1.0 to 2.0; And 1 to 5 parts by weight of a urethane initial polymer (B) obtained by reacting a polyester polyol having a hydroxyl value of 20 to 40 so that an equivalent ratio of hexamethylene diisocyanate and an isocyanate group / hydroxy group is 1 to 5. do.

The present invention will be described in more detail as follows.

(1) urethane initial polymer

For the sake of convenience, the urethane initial polymer represented by the urethane initial polymer (A) is obtained by reacting a mixture of polyols with an isocyanate compound, wherein the equivalent ratio of the isocyanate group and the hydroxyl group is controlled to be 1.0 to 2.0.

Here, the polyol mixture may include at least one alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc.) and at least two active hydrogen atom-containing compounds (e.g., polyalcohols, amines, alkanes). Olamine and polyphenols).

Wherein the polyalcohol includes ethylene glycol, propylene glycol, butane diol, diethylene glycol, glycerin, hexane triol, trimethylol propane, pentaerythritol and the like, amines include ethylene diamine, hexamethylene diamine and the like, alkanes All amines include ethanol amines, propanol amines, and the like, and polyphenols include resorcinol, bisphenols, and the like.

The proper balance of the diol and triol here is to achieve a three-dimensional cross-linking has the strength of the final hardened material and maintain the rubbery elasticity.

The diisocyanate compound used in the production of the urethane initial polymer (A) is selected from raw materials commonly used in the production of the urethane resin, and is not particularly limited. For example, 2,4-rollylene diisocyanate, 2,6-rollylene diisocyanate, phenylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'- diisocyanate, naphthalene-1,5-diisocyanate And hydrides thereof, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1-methyl-2,4-diisocyanate cyclohexane, 1-methyl-2,6- Diisocyanate cyclohexane, triphenylmethane triisocyanate and the like. These compounds may be used alone or in combination.

The polyol is reacted with the isocyanate compound so that the monomer ratio of isocyanine group / hydroxy group is 1.0 to 2.0. If the NCO / OH equivalent ratio is less than 1.0, the urethane initial polymer (A) has an excessive viscosity, making it difficult to apply to the adhesive composition, and if it exceeds 2.0, it has a large amount of free isocyanate, which causes storage problems.

(2) Urethane Initial Polymer (B)

The urethane initial polymer (B) is obtained by reacting a polyester polyol having a hydroxyl value of 20 to 40 with hexamethylene diisocyanate, and reacting such that the NCO / OH equivalent ratio is 1 to 5.

The polyester polyols that can be used here are polycondensates of polyhydric acids with poly hydroxyl compounds such as glycols, and suitable polyacids are aromatic dicarboxylic acids or derivatives thereof. Specific examples include terephthalic acid, isophthalic acid, phthalic anhydride and aliphatic and cycloaliphatic acids such as adipic acid, sebacic acid, fumaric acid, azelaic acid and the like. Polyhydroxyl compounds also include ethylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, hexane glycol, trimethylol propane, glycerin pentaerythritol and the like.

If the hydroxyl group of such polyester polyol is greater than 40, the melting point is increased and the final adhesion strength is lowered. If it is less than 20, the initial adhesion strength is lowered and the viscosity is excessive.

The hexa methylene diisocyanate compound used in the preparation of the urethane initial polymer (b) is used to provide initial adhesion.

The equivalent ratio of isocyanate groups in the hexamethylene diisocyanate compound to the hydroxy groups is preferably 1 to 5, if the equivalent ratio is less than 1, the viscosity becomes excessive, making it impossible to use. This results in a drop in strength and the film is struck.

The urethane initial polymer (b) obtained as mentioned above is mixed at 1-5 weight part with respect to 100 weight part of urethane initial polymers (a). If the content of the urethane initial polymer (b) is less than 1 part by weight with respect to the urethane initial polymer (a), it cannot provide the required initial adhesion, and if it is more than 5 parts by weight, the bond strength in the final cured structure is lowered and the adhesive composition is used. Reduces the elasticity of the rubbery phase.

Meanwhile, the adhesive composition of the present invention may include a plasticizer, a filler, a thixotropic agent, a thickener, a catalyst, an ultraviolet absorber, a dye, a pigment, a flame retardant, and the like, and various well-known additives may be used.

The adhesive composition according to the present invention is obtained by adding a urethane initial polymer (A) and a urethane initial polymer (B) to a mixer filled with nitrogen gas, and then adding plasticizers, fillers and other additives, and mixing them thoroughly under vacuum. Lose.

The resulting molten phase composition may be placed in a suitable container, sealed, cooled and stored.

The composition thus prepared can be melted while heating to apply it where necessary.

For example, when installing windshields in automobiles, the adhesive composition may be applied to both the pane and the window frame at about 50-70 ° C. and then cooled and cured to retain sufficient initial adhesion to avoid sagging of the glass, Exposed to and finally cured to exhibit the required bond strength and elasticity.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Examples 1-10 and Comparative Examples 1-10

(1) Preparation of Urethane Initial Polymer (A)

20 parts by weight of polyoxypropylene diol having an average molecular weight of 1000 to 3000 and 55 parts by weight of polyoxypropylene triol having an average molecular weight of 4000 to 6000 were introduced into a reactor, and dehydrated at 110 ° C. under 50 mmHg for 2 hours. After that, the mixture was allowed to cool, and then the reaction was continued while adding 4.5 parts by weight of toluene diisocyanate (TDI) and 6 parts by weight of 4,4'-diphenylmethane diisocyanate (MDI) with stirring until the free isocyanate was reduced to 1.6%. To obtain the urethane initial polymer (A).                     

(B) Preparation of Urethane Initial Polymer (B)

The polyester polyols having a hydroxyl value of 20 to 40 are dehydrated at 50 mmHg, 110 ° C. for 2 hours in the reactor in the amounts shown in Tables 1 and 2 below. The polyol is cooled to 100 ° C. and then reacted by adding the hexamethylene diisocyanate compounds in the equivalent ratios shown in the following Tables 1 and 2 with stirring to obtain a urethane initial polymer (B).

(3) Preparation of moisture curable adhesive composition

45-50 parts by weight of the urethane initial polymer (A) and the urethane initial polymer (B) of the contents shown in the following Tables 1 and 2 were added 10 parts by weight of a plasticizer, 40 parts by weight of anhydrous carbon black and 10 parts of anhydrous calcium carbonate. Add with portions to continue mixing under vacuum to a sufficient degree.

(4) adhesion strength test

i) Initial adhesion strength test

Each test sample obtained from the adhesive composition shown in the following Tables 1 and 2 was then warmed to 70 ° C. and then applied so that the thickness of the adhesive layer was 5 mm between the glass substrate and the coated steel sheet, which was then applied at a temperature of 20 ° C. and a relative humidity of 65%. After leaving for 10 minutes, the tensile strength test is performed at a rate of 50 mm / min in the direction of 180 °.

ii) final bond strength test

In the same manner as the initial bond strength, the resultant was tested for the material fracture state and the surface peeling property of the peel strength and the shear strength after being left for 7 days at a temperature of 20 ° C. and a relative humidity of 65%.                     

Example One 2 3 4 5 6 7 8 9 10 Urethane Prepolymer (A) Content (parts by weight) 100 100 100 100 100 100 100 100 100 100 Urethane Prepolymer (B) Hydroxyl value (mgKOH / g) 25 28 28 30 32 32 33 35 38 38 Polyol Content (parts by weight) 100 100 100 100 100 100 100 100 100 100 NCO / OH equivalence ratio 1.5 1.5 1.8 1.8 2 3 3 3.5 4 4.5 HDI content (parts by weight) 16.75 19 22.8 24.3 29 43.5 45 55 68 77 Moles per mole of EtOH: HDI 0 0 0 0 0 0 0 0 0 0 Urethane Prepolymer (B) Content (parts by weight) 1.5 1.5 2 2 2.5 3 3 3.5 4 5 Characteristics Initial Attachment Strength (kg / ㎠) 6.75 6.7 5.97 5.5 5.6 5.31 4.1 3.88 2.99 2.1 Final bond strength 100% CF 100% CF 100% CF 100% CF 100% CF 100% CF 100% CF 100% CF 100% CF 100% CF

Comparative Example One 2 3 4 5 6 7 8 9 10 Urethane Prepolymer (A) Content (parts by weight) 100 100 100 100 100 100 100 100 100 100 Urethane Prepolymer (B) Hydroxyl value (mgKOH / g) 10 17 43 50 28 32 28 28 32 32 Polyol Content (parts by weight) 100 100 100 100 100 100 100 100 100 100 NCO / OH equivalence ratio 1.5 1.5 2.0 2.0 0.8 5.5 2 2 2 2 HDI content (parts by weight) 6.8 11.7 38.7 45.1 10.13 79.68 25.3 25.3 29 29 Moles per mole of EtOH: HDI 0 0 0 0 0 0 0.3 0.6 0 0 Urethane Prepolymer (B) Content (parts by weight) 1.5 1.5 1.5 2 2 18 20 2 0.7 7 Characteristics Initial Attachment Strength (kg / ㎠) Not available due to excessive viscosity 0.7 0.84 3.8 4.44 0.7 2.4 2.7 0.5 4.82 Final bond strength 65% CF 60% CF 80% CF 75% CF 100% CF 70% CF 40% CF 50% CF 40% CF

As described in detail above, when masking free isocyanate with mono alcohol or the like as in Comparative Examples 7 to 8, the final bond strength is weakened, the composition according to the present invention is a polyester polyol having a suitable hydroxyl group and By including the urethane initial polymer obtained by reacting hexamethylene diisocyanate at a constant NCO / OH equivalent ratio, it has the advantage of having an excellent final bond strength and excellent initial adhesion strength even at a relatively low amount of use, thereby providing an excellent moisture curable urethane adhesive composition. Can be.

Claims (3)

100 parts by weight of the urethane initial polymer (A) obtained by reacting a mixture of polyols with an isocyanate compound and an isocyanate group / hydroxy group equivalent ratio of 1.0 to 2.0; And A moisture curable urethane adhesive composition comprising 1 to 5 parts by weight of a urethane initial polymer (B) obtained by reacting a polyester polyol having a hydroxyl value of 20 to 40 with an equivalent ratio of hexamethylene diisocyanate and an isocyanate group / hydroxy group. . The moisture-curable urethane adhesive composition according to claim 1, wherein the polyol mixture constituting the urethane prepolymer (a) is obtained by addition reaction of at least one alkylene oxide with at least two active hydrogen atom-containing compounds. The moisture-curable urethane adhesive composition according to claim 1, wherein the polyester polyol constituting the urethane initial polymer (b) is a polycondensate of a polyvalent acid and a polyhydroxyl compound.