Patent Description:
Generally, polyurethane resins have a urethane bond in a molecule and excellent abrasion resistance, oil resistance, solvent resistance, etc., and are used in diverse fields including adhesive, injection molding, ink, paint, foamed body, etc..

Document <CIT> describes a polyurethane resin composition comprising a first urethane resin (a urethane prepolymer), a second urethane resin (obtained by reacting a polyether polyol, an aminoalkoxy silane-based compound and an isocyanate-bonded biuret body), a plasticizer, a pigment, and a catalyst.

As a case of using such a polyurethane resin as an adhesive, a case of attaching a base material such as glass onto a coated surface of a car body may be included. However, since the conventional polyurethane resin had degraded adhesiveness with the coated surface of a car body, a primer was required to be applied on the coated surface first, a polyurethane resin was applied thereon, and then, a base material such as glass was attached. Like this, a primer coating process was essentially, and in case of using the conventional polyurethane resin, there were problems in that a process for attaching a base material such as glass onto the coated surface of a car body became complicated.

In addition, the conventional polyurethane resin had a short pot life, degraded workability, and degraded adhesiveness at a low temperature, and there were defects of having lots of limitations on usage environments of the polyurethane resin.

The present invention provides a polyurethane resin composition which may sufficiently secure a pot life and has excellent adhesiveness in a broad temperature range.

The present invention provides a polyurethane resin composition, comprising:.

The polyurethane resin composition of the present invention has excellent adhesiveness in a broad temperature range (for example, <NUM> to <NUM>), and secures a sufficient pot life and has excellent workability. Particularly, when the polyurethane resin composition of the present invention is used as an adhesive for attaching a base material such as glass onto the coated surface of a car body, excellent adhesive effects may be obtained without applying a primer on the coated surface of the car body.

In the present disclosure, NCO% may represent the content of an unreacted isocyanate group by wt% based on the total weight of a resin.

The present invention relates to a <NUM>-liquid type polyurethane resin composition which is characterized in including a specific urethan resin and showing excellent adhesiveness, and particular explanation thereon is as follows.

The polyurethane resin composition of the present invention includes a first urethane resin, a second urethane resin obtained by reacting a polyether polyol, an aminoalkoxy silane-based compound and an isocyanate-bonded biuret body, and a plasticizer, wherein the aminoalkoxy silane-based compound is a compound represented by the following Chemical Formula <NUM>:
<CHM>
wherein R<NUM> and R<NUM> are the same or different, and are each independently an alkylene group of C<NUM> to C<NUM>, R<NUM> to R<NUM> are the same or different, and are each independently an alkyl group of C<NUM> to C<NUM>, and a and b are integers of <NUM> to <NUM>, respectively.

The first urethane resin plays an importance role on dispersibility, thixo properties, adhesiveness, and mechanical properties.

The first urethane resin may be a urethane prepolymer obtained by reacting a polyol compound and an isocyanate compound.

The polyol compound may include, for example, one or more selected from the group consisting of a polyethylene glycol, a polypropylene glycol, a polytetramethylene glycol, and a polypropylene triol. In this case, the polyol compound may have a weight average molecular weight (Mw) of <NUM> to <NUM>,<NUM>/mol, <NUM>,<NUM> to <NUM>,<NUM>/mol, <NUM>,<NUM> to <NUM>,<NUM>/mol, or <NUM>,<NUM> to <NUM>,<NUM>/mol.

The isocyanate compound may include, for example, <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, or isophorone diisocyanate.

For the reaction of the polyol compound and the isocyanate compound, a plasticizer (first plasticizer) may be used. Particular examples of the plasticizer may include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, diisodecyl phthalate, diisononyl phthalate, or mixtures thereof.

The first urethane resin may have a weight average molecular weight (Mw) of <NUM>,<NUM> to <NUM>,<NUM>/mol, <NUM>,<NUM> to <NUM>,<NUM>/mol, or <NUM>,<NUM> to <NUM>,<NUM>/mol, in consideration of the viscosity, flexibility, etc. of the polyurethane resin composition.

In addition, the first urethane resin may have the content of an unreacted isocyanate group (NCO%) of <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM> based on the total weight of the resin.

The first urethane resin may be included in an amount of <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight in the composition based on <NUM> to <NUM> parts by weight of a second urethane resin. If the amount of the first urethane resin deviates from the aforementioned range, the flexibility, adhesiveness, heat resistance, etc. of the polyurethane resin composition may be deteriorated.

The second urethane resin plays an important role on adhesiveness with a base material.

The second urethane resin is obtained by reacting a polyether polyol, an aminoalkoxy silane-based compound and an isocyanate-bonded biuret body. In this case, the second urethane resin may be a different urethane resin from the first urethane resin.

The polyether polyol absorbs moisture in the air due to the hygroscopic properties of the material itself to accelerate the hydrolysis of the aminoalkoxy silane-based compound, and reacts with the biuret body to form a urethane bond. Such a polyether polyol may include one or more selected from the group consisting of a polyethylene glycol, a polypropylene glycol, a polybutylene glycol and a polytetramethylene glycol. In addition, the polyether polyol may have a weight average molecular weight (Mw) of <NUM> to <NUM>,<NUM>/mol, <NUM> to <NUM>,<NUM>/mol, or <NUM> to <NUM>/mol.

The aminoalkoxy silane-based compound improves the adhesiveness, reactivity at a low temperature, etc. of the second urethane resin. Particularly, the aminoalkoxy silane-based compound is represented by Chemical Formula <NUM> below. Alternatively, the aminoalkoxy silane-based compound may be a compound represented by Chemical Formula <NUM>, which is not encompassed by the claims.

In this case, the alkyl group may include, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, etc, particularly, a methyl group, an ethyl group or a propyl group. In addition, the alkyl group may be a linear or branch type.

The aryl group may be, for example, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, biphenylene, etc., particularly, a phenyl group.

The alkylene refers to a branched, linear or cyclic radical, derived from an alkyl group by removing one hydrogen atom from a carbon atom thereof. That is, the alkylene may be a divalent radical.

The compound represented by Chemical Formula <NUM> may be a compound obtained by reacting an amino silane compound and an epoxy silane compound in a molar ratio of <NUM> : <NUM> to <NUM> : <NUM>. In this case, particular examples of the amino silane compound may include N-<NUM>-(aminoethyl)-<NUM>-aminopropylmethyldimethoxysilane, N-<NUM>-(aminoethyl)-<NUM>-aminopropyltrimethoxysilane, <NUM>-aminopropyltrimethoxysilane, <NUM>-aminopropyltriethoxysilane, or N-phenyl-<NUM>-aminopropyltrimethoxysilane. In addition, particular examples of the epoxy silane may include <NUM>-glycidoxypropyl methyldimethoxysilane, <NUM>-glycidoxypropyl trimethoxysilane, <NUM>-glycidoxypropyl methyldiethoxysilane, or <NUM>-glycidoxypropyl triethoxysilane.

Particularly, the aminoalkoxy silane-based compound represented by Chemical Formula <NUM>, which is not encompassed by the claims, may be N-phenyl-gamma-aminopropyltrimethoxy silane as an aromatic ring-bonded aminoalkoxy silane-based compound.

Particularly, the aminoalkoxy silane-based compound represented by Chemical Formula <NUM> may be a compound obtained by reacting <NUM>-aminopropyltriethoxysilane and <NUM>-glycidoxypropyl trimethoxysilane in a molar ratio of <NUM> : <NUM> to <NUM> : <NUM>, for example, in a molar ratio of <NUM> : <NUM> to <NUM> : <NUM>.

The isocyanate-bonded biuret body improves the adhesiveness, crosslinking properties, etc. of the second urethane resin.

The isocyanate bonded to the biuret body may include, for example, 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.

The biuret body may be a biuret body in which three or more isocyanate groups are bonded. Particularly, the biuret body may be <NUM>,<NUM>,<NUM>-tris(<NUM>-isocyanatohexyl)biuret or a trimer of hexamethylene diisocyanate.

The isocyanate-bonded biuret body may have the unreacted isocyanate group content (NCO%) of <NUM> to <NUM>, or <NUM> to <NUM> based on the total weight of the biuret body.

The second urethane resin may be obtained by reacting the polyether polyol, the aminoalkoxy silane-based compound and the isocyanate-bonded biuret body in a molar ratio of <NUM>: <NUM> to <NUM>: <NUM> to <NUM>.

The second urethane resin may have a weight average molecular weight (Mw) of <NUM> to <NUM>,<NUM>/mol in consideration of the viscosity, adhesiveness, etc. of the polyurethane resin composition. In addition, the second urethane resin may have the unreacted isocyanate group content (NCO%) of <NUM> to <NUM>, or <NUM> to <NUM> based on the total weight of the resin.

The second urethane resin may be included in an amount of <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight in the composition based on <NUM> to <NUM> parts by weight of the first urethane resin. If the amount of the second urethane resin deviates from the aforementioned range, the adhesiveness (particularly, adhesiveness at a low temperature), etc. of the polyurethane resin may be deteriorated.

The composition may include the first urethane resin and the second urethane resin in a weight ratio of <NUM> : <NUM> to <NUM> : <NUM>, or a weight ratio of <NUM> : <NUM> to <NUM> : <NUM>. If the mixing weight ratio of the first urethane resin and the second urethane resin deviates from the aforementioned range, the adhesiveness of the polyurethane resin may be deteriorated, or curing may be delayed, and crack may be generated in a coated film.

The plasticizer (second plasticizer) included in the polyurethane resin composition of the present invention plays the role of providing the polyurethane resin composition with flexibility, elasticity, etc..

The plasticizer may include, for example, one or more selected from the group consisting of a phthalate-based plasticizer and a phosphate-based plasticizer.

The phthalate-based plasticizer may include, for example, one or more selected from the group consisting of dibutyl phthalate, di-<NUM>-ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate and butylbenzyl phthalate.

The phosphate-based plasticizer may include, for example, one or more selected from the group consisting of <NUM>-ethylhexyldiphenyl phosphate, tri-cresyl phosphate and cresyldiphenyl phosphate.

In this case, in order to improve the thermal stability together with flexibility and plasticity of the polyurethane resin composition, a mixture of diisononyl phthalate and <NUM>-ethylhexyldiphenyl phosphate may be used as the plasticizer.

The plasticizer may be included in an amount of <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight in the composition based on <NUM> to <NUM> parts by weight of the first urethane resin. If the amount of the plasticizer deviates from the aforementioned range, the flexibility, plasticity, etc. of the polyurethane resin composition may be deteriorated.

The polyurethane resin composition of the present invention may further include a pigment and a catalyst.

The catalyst included in the polyurethane resin composition of the present invention plays the role of controlling the curing reaction rate of the polyurethane resin composition to secure a sufficient pot life during a painting process.

The catalyst may include, for example, 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>-ethanediyl)bismorpholine and dimethyl-<NUM>-morphline ethaneamine.

Particularly, the catalyst may include dioctyltin dilaurate and <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanediyl)bismorpholine. In addition, the catalyst may further include one or more additional catalysts selected from the group consisting of dibutyltin mercaptide and dimethyl-<NUM>-morpholine ethaneamine. For example, the catalyst may include dioctyltin dilaurate, <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanediyl)bismorpholine and dibutyltin mercaptide, or may include dioctyltin dilaurate, <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanediyl)bismorpholine and dimethyl-<NUM>-morpholine ethaneamine.

In case where the polyurethane resin composition uses the above-described three types of catalysts, the curing reaction rate of the polyurethane resin composition may be suitably controlled, and a sufficient pot life may be secured during a painting process.

Particularly, the catalyst may include dioctyltin dilaurate, <NUM>,<NUM>'-(oxydi-<NUM>,<NUM>-ethanediyl)bismorpholine and the additional catalyst in a weight ratio of <NUM> to <NUM>: <NUM> to <NUM>: <NUM> to <NUM>, or a weight ratio of <NUM> to <NUM>: <NUM> to <NUM>: <NUM> to <NUM>. If the mixing ratio of catalyst deviates from the aforementioned range, the control of the curing reaction rate of the polyurethane resin composition may become difficult.

The catalyst may be included in the composition in an amount of <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight based on <NUM> to <NUM> parts by weight. If the amount of the catalyst deviates from the aforementioned range, the curing reactivity of the polyurethane resin composition may be deteriorated, or the pot life may be reduced, and workability may be deteriorated.

The pigment plays the role of improving the strength of a polyurethane resin composition and providing color.

The pigment may include, for example, carbon black, calcium carbonate, titanium dioxide (TiO<NUM>), iron oxide yellow, iron oxide red, etc..

The pigment may be included in an amount of <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight in the composition based on <NUM> to <NUM> parts by weight of the first urethane resin. If the amount of the pigment deviates from the aforementioned range, the strength of the polyurethane resin composition may be degraded, or the control of the viscosity of the polyurethane resin composition may become difficult.

In addition, the polyurethane resin composition of the present invention may further include a thickener commonly used for controlling the viscosity of the composition.

As described above, since the polyurethane resin composition of the present invention includes the second urethane resin obtained by reacting specific compounds, adhesiveness is excellent together with flexibility, heat resistance, strength, etc. Due to the excellent adhesiveness, if the polyurethane resin composition of the present invention is used as an adhesive for attaching a base material such as glass to the coated surface of a car body, the base material may be directly attached without applying a primer on the coated surface.

Hereinafter, the present invention will be explained particularly referring to embodiments. However, the embodiments are only for illustrating the present invention, and the present invention is not limited thereto.

Polypropylene glycol, diisononyl phthalate, and polypropylene triol were injected into a glass flask equipped with a stirrer, a condenser and a thermometer, and the pressure was reduced to vacuum for <NUM> hours, while slowly raising the temperature to <NUM>. Then, the temperature was reduced to <NUM> or less, methylene diphenyl diisocyanate (MDI) was injected, and the heating was secured. Then, the reaction was performed while the temperature was maintained to <NUM> to <NUM> until NCO% reached <NUM>. After finishing the reaction, the temperature was reduced to <NUM>, and a first urethane resin having a viscosity of <NUM>,<NUM> cps, and a weight average molecular weight (Mw) of <NUM>,<NUM>/mol was prepared.

Polypropylene glycol was injected into a glass flask equipped with a stirrer, a condenser and a thermometer, and the pressure was reduced to vacuum for <NUM> hours, while raising the temperature to <NUM>. Then, the temperature was reduced to <NUM> or less, <NUM>,<NUM>,<NUM>-tris(<NUM>-isocyanatohexyl)biuret was injected, and the heating was secured. Then, the reaction was performed while the temperature was maintained to <NUM> until NCO% reached <NUM> to <NUM>. After that, the temperature was reduced to <NUM>, N-phenyl-gamma-aminopropyltrimethoxy silane was injected, and the reaction was performed while maintaining the temperature to <NUM> until NCO% reached <NUM>. After finishing the reaction, the temperature was reduced to <NUM>, and a second urethane resin having a viscosity of <NUM>,<NUM> cps was prepared.

Into a mixer apparatus of a SUS material, which is connected with a vacuum pump and a heatable jacket, and in which high viscosity rotation stirring and wall scrubbing are possible, the first urethane resin prepared above, and a plasticizer were injected, and stirring was performed while raising the temperature to <NUM>. Then, a pigment was injected, stirring was performed for <NUM> minutes, and the pressure was reduced for <NUM> minutes with vacuum of less than <NUM> torr to remove moisture. Then, a catalyst and the second urethane resin prepared above were injected, and stirring was performed for <NUM> minutes to prepare a polyurethane resin composition having a viscosity of <NUM>,<NUM> Ps, and the NCO% of <NUM>.

During preparing the resins and the composition, the composition of the components were controlled as in Table <NUM> below.

Polyurethane resin compositions were prepared by the same method as in Comparative Example <NUM> except for applying the compositions in Tables <NUM> and <NUM> below. In this case, the viscosity was controlled using a thickener in Comparative Example <NUM>.

Polyurethane resin compositions were prepared by the same method as in Comparative Example <NUM> except for applying the components in Table <NUM> below.

Physical properties on the polyurethane resin compositions prepared in the Examples and Comparative Examples were evaluated as follows, and the results are shown in Tables <NUM> and <NUM>.

Claim 1:
A polyurethane resin composition, comprising:
a first urethane resin;
a second urethane resin obtained by reacting a polyether polyol, an aminoalkoxy silane-based compound and an isocyanate-bonded biuret body; and
a plasticizer,
wherein the aminoalkoxy silane-based compound is a compound represented by the following Chemical Formula <NUM>:
<CHM>
Wherein R<NUM> and R<NUM> are the same or different, and are each independently an alkylene group of C<NUM> to C<NUM>,
R<NUM> to R<NUM> are the same or different, and are each independently an alkyl group of C<NUM> to C<NUM>, and
a and b are integers of <NUM> to <NUM>, respectively.