Patent Description:
In general, a polyurethane resin has a urethane bond in the molecules thereof, and is excellent in abrasion resistance, oil resistance, solvent resistance, and the like, and is used in various fields such as adhesives, injection molding, ink, paint, and foam.

Examples of cases in which such a polyurethane resin is used as an adhesive may include cases of bonding a substrate such as glass on a painted surface of an automobile body. However, a typical polyurethane resin has poor adhesiveness to a painted surface of an automobile body, and thus, a primer is first applied on the painted surface and then a polyurethane resin is applied thereon (or a polyurethane resin is first applied, and then the primer is applied again thereon), followed by adhering a substrate such as glass thereto. Since a primer application process is essentially required as described above, when a typical polyurethane resin is used, there is a problem in that a process of adhering a substrate such as glass on a painted surface of an automobile body becomes complicated.

In addition, a typical polyurethane resin has short pot life, so that the workability thereof is poor, and the adhesiveness thereof at low temperatures is also poor, so that there is a problem in that an environment in which the polyurethane resin is used is limited.

An aspect of the present invention provides a polyurethane resin which is excellent in adhesiveness in a wide temperature range and capable of securing sufficient pot life.

According to an aspect of the present invention, provided is a polyurethane resin composition comprising a urethane resin, an adhesive resin obtained by reacting an aminoalkoxy silane-based compound and a biuret body bonded with isocyanate, and a first plasticizer, wherein in the reaction, the aminoalkoxy silane-based compound is used in an amount of <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition.

A polyurethane resin composition of the present invention is excellent in adhesiveness in a wide temperature range (for example, <NUM> to <NUM>), and also excellent in workability since sufficient pot life is secured. Particularly, when the polyurethane resin composition of the present invention is used as an adhesive (sealant) for adhering a substrate such as glass to a painted surface of an automobile body, an excellent adhesive effect may be achieved without applying a primer on the painted surface of the automobile body and/or a glass surface.

The polyurethane resin composition of the present invention characterized in that an excellent adhesive effect may be achieved by including a specific adhesive resin, as described in detail below.

The polyurethane resin composition of the present invention includes a urethane resin, an adhesive resin, and a first plasticizer.

The urethane resin included in the polyurethane resin composition of the present invention may be a urethane prepolymer obtained by a reaction of a polyol compound and a polyisocyanate compound.

The polyol compound may be one or more selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polypropylene triol. The weight average molecular weight (g/mol) of the polyol compound may be <NUM> to <NUM>,<NUM>, specifically <NUM>,<NUM> to <NUM>,<NUM>.

The polyisocyanate compound may be one or more selected from the group consisting of <NUM>,<NUM>-toluene diisocyanate (<NUM>,<NUM>-TDI), <NUM>,<NUM>-toluene diisocyanate (<NUM>,<NUM>-TDI), <NUM>,<NUM>'-diphenylmethylene diisocyanate (<NUM>,<NUM>'-MDI), <NUM>,<NUM>'-diphenylmethylene diisocyanate (<NUM>,<NUM>'-MDI), <NUM>,<NUM>-phenylene diisocyanate, <NUM>,<NUM>-naphthalene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like.

In the reaction of a polyol compound and a polyisocyanate compound, a third plasticizer may be used. Specific examples of the third plasticizer may be dioctyl phthalate, dibutyl phthalate, dioctyl adipate, diisodecyl phthalate, diisononyl phthalate, or a mixture thereof.

The weight average molecular weight of the urethane resin may be <NUM>,<NUM> to <NUM>,<NUM> considering the viscosity, flexibility, and the like of the polyurethane resin composition.

In addition, the content of the urethane resin may be <NUM> to <NUM> parts by weight on the basis of <NUM> parts by weight of the polyurethane resin composition. When the content of the urethane resin is out of the above range, the flexibility, heat resistance, and the like of the polyurethane resin composition may be deteriorated.

The adhesive resin included in the polyurethane resin composition of the present invention may be a silane-based resin obtained by reacting an aminoalkoxy silane-based compound and a biuret body bonded with isocyanate.

The biuret body bonded with isocyanate may mean a self-condensation product in which an isocyanate monomer is self-condensed to have a biuret bond.

The aminoalkoxy silane-based compound may be one or more selected from the group consisting of bis(trialkoxysilylpropyl)amine, N-<NUM>-(aminoethyl)-<NUM>-aminopropylmethyldimethoxysilane, N-<NUM>-(aminoethyl)-<NUM>-aminopropyltrimethoxysilane, <NUM>-aminopropyltrimethoxysilane, <NUM>-aminopropyltriethoxysilane, N-phenyl-<NUM>-aminopropyltrimethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, and <NUM>-aminopropyltriethoxysilane. At this time, the bis(trialkoxysilylpropyl)amine may specifically be one or more selected from the group consisting of bis(trimethoxysilylpropyl)amine, bis(triethoxysilylpropyl)amine, and bis(tripropoxysilylpropyl)amine.

Here, the present invention may provide a polyurethane resin composition having excellent adhesiveness (particularly, low-temperature adhesiveness) by, when reacting an aminoalkoxy silane-based compound to the biuret body, allowing the usage amount thereof to be relatively large to prepare an adhesive resin, and introducing the prepared adhesive resin into the polyurethane resin composition. Specifically, the aminoalkoxy silane-based compound may be used in an amount of <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition.

The isocyanate bonded to the biuret body may include one or more selected from the group consisting of hexamethylene diisocyanate, cyclopentylene-<NUM>,<NUM>-diisocyanate, cyclohexylene-<NUM>,<NUM>-diisocyanate, hexahydroxylylene diisocyanate, dicyclohexyl-<NUM>,<NUM>-diisocyanate, <NUM>-methyl-<NUM>,<NUM>-diisocyanatocyclohexane, <NUM>-methyl-<NUM>,<NUM>-diisocyanatocyclohexane, bis(<NUM>-isocyanatocyclohexyl)methane, <NUM>,<NUM>-diisocyanatocyclohexane, and <NUM>,<NUM>-diisocyanatocyclohexane. Specifically, the biuret body may be <NUM>,<NUM>,<NUM>-tris(<NUM>-isocyanatohexyl)biuret.

Here, the reaction ratio of the aminoalkoxy silane-based compound and the biuret body may be a weight ratio of <NUM>:<NUM> to <NUM> considering the physical properties of the adhesive resin.

Meanwhile, a second plasticizer may be added in the process of obtaining an adhesive resin by reacting the aminoalkoxy silane-based compound with the biuret body. Specific examples of the second plasticizer may be dioctyl phthalate, dibutyl phthalate, dioctyl adipate, diisodecyl phthalate, diisononyl phthalate, or a mixture thereof.

The content of the adhesive resin obtained as described above may be <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition. When the content of the adhesive resin is out of the above range, the adhesiveness, crosslinking, and the like of the polyurethane resin composition may be deteriorated.

The first plasticizer included in the polyurethane resin composition of the present invention is to impart flexibility, elasticity, and the like to the polyurethane resin composition, and may be one or more selected from the group consisting of a phthalate-based plasticizer and a phosphate-based plasticizer.

The phthalate-based plasticizer may be one or more selected from the group consisting of di-butyl phthalate, di-<NUM>-ethylhexyl phthalate, di-isononyl phthalate, di-isodecyl phthalate, and butylbenzyl phthalate. The phosphate-based plasticizer may be one or more selected from the group consisting of <NUM>-ethylhexyl diphenyl phosphate, tri-cresyl phosphate, and cresyldiphenyl phosphate. Here, in order to further increase the flexibility and plasticity as well as thermal stability of the polyurethane resin composition, a mixture of diisononyl phthalate and <NUM>-ethylhexyldiphenyl phosphate may be used as the first plasticizer.

The content of the first plasticizer may be <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition. When the content of the first plasticizer is out of the above range, the flexibility, plasticity, and the like of the polyurethane resin composition may be deteriorated.

Meanwhile, the polyurethane resin composition of the present invention may further include one or more selected from the group consisting of a pigment, a catalyst, and an adhesion promoter in order to increase the physical properties of a coating film.

The pigment further included in the polyurethane resin composition of the present invention is to increase the strength of the coating film and impart color thereto. Specific examples thereof may include carbon black, calcium carbonate, titanium dioxide (TiO<NUM>), iron oxide yellow, iron oxide red, and the like.

The content of the pigment may be <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition. When the content of the pigment is out of the above range, the strength of the coating film may be deteriorated, or it may be difficult to control the viscosity of the polyurethane resin composition and impart required color to the coating film.

The catalyst further included in the polyurethane resin composition of the present invention controls the reactivity of the polyurethane resin composition. The catalyst may be one or more selected from the group consisting of dimethyltin dioleate, dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin octanoate, dibutyltin mercaptide, dioctyltin dilaurate, dioctyltin mercaptide, dioctyltin dimaleate, <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanedyl)bismorpholine, and dimethyl-<NUM>-morpholine ethaneamine. Here, in order to optimize the curing reactivity of the polyurethane resin composition to secure sufficient pot life, a mixture of dibutyltin mercaptide and <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanedyl)bismorpholine may be used as the catalyst.

The content of the catalyst may be <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition. When the content of the catalyst is out of the above range, the curing reactivity of the polyurethane resin composition may be deteriorated or the pot life thereof may be shortened to deteriorated workability.

The adhesion promoter further included in the polyurethane resin composition of the present invention is to increase the adhesiveness of the coating film, and specific examples thereof may include <NUM>,<NUM>,<NUM>-tris(<NUM>-isocyanatohexyl)biuret, and the like.

The content of the adhesion promoter may be <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition. When the content of the adhesion promoter is out of the above range, the physical properties of the coating film may be deteriorated or the economic feasibility of the polyurethane resin composition may be deteriorated.

In addition, the polyurethane resin composition of the present invention may further comprise a thickener commonly used to control the viscosity of a composition.

The polyurethane resin composition of the present invention described above includes an adhesive resin obtained by reacting a relatively high amount of the aminoalkoxy silane-based compound with a biuret body, and thus, is excellent in adhesiveness as well as hardness, strength, and the like. As such, the polyurethane resin composition of the present invention is excellent in adhesiveness, and thus, when used as an adhesive (sealant) for adhering a substrate such as glass to a painted surface of an automobile body, the substrate may be directly adhered to the painted surface as well as a glass surface without the application of a primer.

Hereinafter, the present invention will be described in detail through embodiments.

However, the following Examples are illustrative of the present invention.

Polypropylene glycol, di-isononyl phthalate, and polypropylene triol were added to a glass flask equipped with a stirrer, a condenser, and a thermometer and having a hose of a vacuum pump connected thereto, and then vacuum decompression was performed for <NUM> hours while gradually raising the temperature to <NUM>. Next, after cooled to <NUM> or less, methylene diphenyl di-isocyanate (MDI) was added to the mixture to identify exotherm, and then the mixture was reacted such that the NCO wt% was to be <NUM> to <NUM> wt% while maintaining a temperature of <NUM> to <NUM>. After the completion of the reaction, the mixture was cooled to <NUM> to prepare a urethane resin having a viscosity (when measured at <NUM> using a Brookfield Viscometer) of <NUM>,<NUM> cPs, an NCO wt% of <NUM> wt%, and a weight average molecular weight of <NUM>,<NUM>.

<NUM>,<NUM>,<NUM>-Tris(<NUM>-isocyanatohexyl)biuret and di-isononyl phthalate were added to a glass flask equipped with a stirrer, a condenser, and a thermometer and having a hose of a vacuum pump connected thereto, and then the mixture was stirred for <NUM> minutes. Next, bis(trimethoxysilylpropyl)amine) was dropped uniformly for <NUM> minutes. Thereafter, while maintaining the temperature not to exceed <NUM>, an NCO wt% was measured every hour, and when the measured NCO wt% satisfied <NUM> to <NUM> wt%, the reaction was terminated. After the completion of the reaction, the mixture was cooled to <NUM> to obtain an adhesive resin having a viscosity of <NUM>,<NUM> cPs and an NCO wt% of <NUM> wt%.

The urethane resin prepared above and di-isononyl phthalate which is a plasticizer were added to a mixer device having a vacuum pump made of an SUS material connected thereto, having a heatable jacket, and capable of high-viscosity rotational stirring and air-wall scrubbing, and stirring was performed while raising the temperature to <NUM>. Next, carbon black was added thereto as a pigment, and the mixture was stirred for <NUM> minutes. Thereafter, decompression was performed for <NUM> minutes to a vacuum of less than <NUM> Torr to remove moisture. Then, <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanedyl) bismorpholine and dibutyl tin mercaptide as catalysts, <NUM>,<NUM>,<NUM>-tris(<NUM>-isocyanatohexyl)biuret as an adhesion promoter, <NUM>-ethylhexyl diphenyl phosphate as a plasticizer were added thereto and the mixture was stirred for <NUM> minutes to obtain a polyurethane resin composition having a viscosity of <NUM>,<NUM> cPs and an NCO wt% of <NUM> wt%. At this time, the composition of each component is as shown in Table <NUM> below.

A polyurethane resin composition was prepared in the same manner as in Example <NUM> except that the composition of Table <NUM> below was applied.

The physical properties of the polyurethane resin composition prepared in each of Examples and Comparative Examples were evaluated as follows, and the results are shown in Tables <NUM> and Table <NUM>, respectively.

Claim 1:
A polyurethane resin composition comprising:
a urethane resin;
an adhesive resin obtained by reacting an aminoalkoxy silane-based compound and a biuret body bonded with isocyanate; and
a first plasticizer, wherein
in the reaction, the aminoalkoxy silane-based compound is included in <NUM> to <NUM> parts by weight based on <NUM> parts by weight of the polyurethane resin composition.