KR101645848B1 - Urethane oligomer comprising reactive silane groups and water-dispersed polyurethane resin composition having core-shell structure and method thereof - Google Patents

Abstract

The present invention provides a process for preparing a prepolymer comprising the steps of: a) reacting a polyol and an isocyanate to prepare a prepolymer having a terminal NCO group; b) preparing a silylated urethane oligomer resin represented by the following formula (2) by mixing at least one reactive silane in the terminal NCO group of the prepolymer; c) adding a polyol and a hydrophilic polyol to the isocyanate to prepare a prepolymer having a terminal NCO group; And d) mixing the silylated urethane oligomer of Formula 2 with the prepolymer of Step c); And a method for producing the polyurethane resin based on an aqueous dispersion of a core and a shell structure. The present invention also relates to a water-dispersed polyurethane resin having a core and a shell structure, which is improved in water resistance, chemical resistance, mechanical properties and storage stability by the above process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane oligomer having a reactive silane group and a water-dispersed polyurethane resin composition having a core / shell structure, and a process for producing the same. 2. Description of the Related Art Urethane oligomer having a reactive silane group,

The present invention relates to a urethane oligomer having a reactive silane group and a water-dispersed polyurethane resin composition having a core and shell structure, and a process for producing the same.

Recently, solvent type polyurethane using volatile organic compounds (VOC) as a solvent has been shown to be toxic to humans, and environmental problems have been caused, and restrictions on the use amount and volatilization of organic solvents have been strengthened. As a result, water-dispersed polyurethane dispersion (PUD), which uses water as an alternative to conventional organic solvent-based resins, is in the spotlight. There are two methods of manufacturing the PUD: a method of adding a surfactant in water to facilitate dispersion of the resin and a method of introducing a hydrophilic functional group into the resin without using a surfactant. The latter method takes much time in the manufacturing process compared with the former, but is preferred because it improves physical properties such as mechanical strength.

However, PUD is an environmentally friendly process, but its water resistance, chemical resistance, and mechanical properties tend to be lower than solvent type polyurethane resin. In this regard, a method for securing excellent corrosion resistance, chemical resistance and mechanical properties when using reactive silane is described in International Publication WO 2009/080441.

 Existing reactive silane research as in the abovementioned International Laid-Open Publication discloses that an isocyanate is reacted with a polyol to form an NCO prepolymer and then a reactive silane is end capped to produce a silane-terminated polyurethane. However, the water-dispersible resin produced by this method has a problem in that the water-dispersibility is poor, and thus the content of the reactive silane is severely limited.

Accordingly, the present inventors have completed a water-dispersed polyurethane resin composition having a core and shell structure and excellent water dispersibility and water resistance and a method for producing the same, in order to solve the above problems.

International Publication No. WO 2009/080441

An object of the present invention is to provide a process for producing an aqueous dispersion-coated polyurethane resin having a core and a shell structure.

Another object of the present invention is to provide an aqueous dispersion-coated polyurethane resin having a core and a shell structure.

In order to accomplish the above object, the present invention provides a process for preparing a prepolymer comprising the steps of: a) reacting a polyol and an isocyanate to prepare a prepolymer having a terminal NCO group; b) preparing a silylated urethane oligomer resin represented by the following formula (2) by mixing at least one reactive silane represented by the following formula (1) in the terminal NCO group of the prepolymer;

[Chemical Formula 1]

(Wherein R ₁ is a C ₁ -C ₄ alkyl or acetyl group and X is an amino group or an epoxy group).

(2)

Wherein R ₂ represents a hydrocarbon backbone of the polyol, R ₃ represents a hydrocarbon skeleton of the isocyanate, and X represents a substituent of the amino group.

c) adding a polyol and a hydrophilic polyol to the isocyanate to prepare a prepolymer having a terminal NCO group; And d) mixing the silylated urethane oligomer of Formula 2 with the prepolymer of Step c); The present invention also provides a method for producing a polyurethane resin dispersed in an aqueous dispersion of a core and a shell.

The term "reactive silane group" of the present invention means a silane group containing an organic functional group which is an amino group or an epoxy group defined by substituent "X ". Also, the reactive silane group of the present invention may include a hydrolyzable group such as methoxy, ethoxy or acetoxy group.

Conventional reactive silane processes include first reacting an isocyanate with a polyol to form an NCO prepolymer, then capping the reactive silane and dispersing it directly in water through neutralization to produce a silane-terminated polyurethane . Alternatively, the process of the present invention comprises the steps of reacting an isocyanate with a polyol to form an NCO prepolymer prior to the synthesis of the water-dispersed polyurethane resin, and capping the reactive silane to the prepolymer to prepare a silylated urethane oligomer It goes through. Then, the water-dispersed silylated polyurethane resin is prepared using the silylated urethane oligomer. The water dispersed polyurethane resin thus synthesized has a core and a shell structure. The outer shell is composed of a polyurethane resin. The inner core is composed of an oligomer containing silane. The silylated polyurethane resin prepared according to the above method can obtain the effect of greatly improving the water resistance, chemical resistance, mechanical properties and storage stability.

Hereinafter, the production method of the present invention will be described in detail.

[Silane-linked urethane oligomer resin]

a) preparing a prepolymer having an NCO group at the terminal by reacting a polyol and an isocyanate, capping one or more reactive silanes corresponding to the above formula (1) at the terminal NCO group of the prepolymer to prepare a silylated urethane oligomer resin ;

[Chemical Formula 1]

In the above formula (1), R ₁ O is a hydrolyzable group, which may be a methoxy, ethoxy or acetoxy group, and X is an organic functional group, which may be an amino group or an epoxy group.

(2)

In the general formula (2), R ₂ represents a hydrocarbon skeleton of a polyol, and R ₃ represents a hydrocarbon skeleton of an isocyanate. X may represent a substituent of an amino group.

The composition ratio of the composition material constituting the silylated urethane oligomer resin of the present invention may preferably include 10 to 30% by weight of the isocyanate, 30 to 80% by weight of the polyol and 10 to 40% by weight of the reactive silane, no.

The isocyanate may have two or more average functional groups and may include, but is not limited to, 4,4-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, And at least one selected from the group consisting of polyfunctional isocyanates derived from polyfunctional isocyanates. More preferably, at least one selected from toluene diisocyanate and isophorone diisocyanate is used. The isocyanate is preferably used in an amount of 10 to 30% by weight based on the total weight of the silylated urethane oligomer resin. If the amount of the isocyanate having two or more functional groups is less than 10% by weight, It may cause a problem that it is difficult to synthesize. If it exceeds 30% by weight, the problem of low chemical resistance may occur.

The polyol may have two or more average functional groups and may include, but is not limited to, a polyester polyol, a carbonate polyol, a caprolactone polyol, a polyoxyethylene glycol, a polyoxypropylene glycone, and a poly It is preferable to use at least one selected from the group consisting of ether polyols. It is more preferable to use a polyester polyol. When the amount of the polyol used is less than 30% by weight, the effect of improving the chemical resistance is small, and when the amount of the polyol is less than 80% by weight, %, The viscosity tends to be high and a problem of difficulty in production may occur. Therefore, it is preferable to use it within the above range. The polyester polyol has a weight average molecular weight of 500 to 2000. It is advantageous in terms of chemical resistance and productivity to use a polyol having the weight average molecular weight range proposed by the present invention.

The reactive silane represented by Formula 1 may include, but is not limited to, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethyl-aminopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, epoxy cy It is preferable to use at least one member selected from the group consisting of hexyl-trimethoxysilane and modified reactive silane derived therefrom. More preferably, at least one selected from aminopropyltriethoxysilane and epoxycyclohexyl-trimethoxysilane is used. The reactive silane is preferably used in an amount of 10 to 40% by weight based on the total weight of the urethane oligomer resin. If the amount of the reactive silane is less than 10%, the effect of improving the chemical resistance is small, It may be difficult to manufacture due to an increase in viscosity. Therefore, it is preferable to use it within the above range.

[Relative Polyurethane Resin in Water and Dispersion of Core and Shell Structure]

The core and shell-water dispersed polyester polyurethane resin of the present invention may be prepared by adding a polyol and a hydrophilic polyol to an isocyanate to prepare a prepolymer having a terminal NCO group; And mixing the prepolymer with the silylated urethane oligomer represented by the formula (2).

In addition, the core and shell sealable water-dispersed polyurethane resin may further include a chain extender, a solvent and a neutralizing agent.

The isocyanate may have 2 or more average functional groups, and examples thereof include 4,4-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate And a multifunctional isocyanate derived therefrom are preferably used. More preferably, at least one selected from dicyclohexylmethane diisocyanate and isophorone diisocyanate is used. The isocyanate is preferably used in an amount of 10 to 30% by weight based on the total weight of the core and the shell-and-sheath dispersed thread-supported polyurethane resin, wherein the amount of the isocyanate having two or more functional groups is 10% By weight, the viscosity tends to be high, which may make it difficult to synthesize. When the amount is more than 30% by weight, the problem of low chemical resistance may occur.

The polyol may have two or more average functional groups and may include, but is not limited to, a polyester polyol, a carbonate polyol, a caprolactone polyol, a polyoxyethylene glycol, a polyoxypropylene glycone, or a poly It is preferable to use at least one selected from ether polyols. It is more preferable to use a carbonate polyol. The polyol may be used in an amount of 30 to 60% by weight based on the total weight of the aqueous dispersion-coated polyurethane resin. When the amount of the polyol is less than 30% by weight, If the amount is more than 60% by weight, the viscosity tends to increase and a problem of difficulty in production may arise. The polyester polyol has a weight average molecular weight of 500 to 2000. It is advantageous in terms of chemical resistance and productivity to use a polyol having the weight average molecular weight range proposed by the present invention.

In the present invention, the hydrophilic polyol imparts hydrophilicity to the urethane chain to facilitate water dispersion. Preferably, it may have two or more functional groups, and includes, but is not limited to, dimethylolpropionic acid, dimethylolbutanoic acid, polyoxyethylene glycol, polycaprolactone diol containing a carboxyl group in the side chain, sulfone Group, and a polyoxyethylene group-substituted polyoxyethylene group-substituted polyoxyethylene group-substituted polyether diol and an alkoxy group-substituted polyoxyethylene group in the side chain. The hydrophilic polyol may be used in an amount of 2 to 10% by weight based on the total weight of the core and the shell-and-sheath dispersed polyurethane resin. When the amount of the hydrophilic polyol is less than 2% by weight, It may be difficult to disperse the water, and when it exceeds 10% by weight, the water resistance may be lowered.

The solvent may be any solvent commonly used in the art for producing the water-dispersed polyurethane resin, and it is preferable to use at least one selected from N-methylpyrrolidone and acetone. The solvent is preferably used in an amount of 5 to 25% by weight based on the total weight of the core and the shell-and-sheath water-dispersed polyurethane resin. If the solvent is used outside the above range, Can be.

The neutralizing agent may be a common solvent used in the art to produce an aqueous dispersion polyurethane resin, preferably triethylamine. The use amount of the neutralizing agent is preferably 1 to 5% by weight, and less than 1% by weight of the neutralizing agent is less effective when it is used. If it exceeds 5% by weight, odor and discoloration may occur, It is recommended to use it within the range.

The method of the present invention may also

e) adding water or distilled water to the mixture of step d), dispersing it in water, adding a chain extender, and subjecting it to chain extension reaction; . ≪ / RTI > The chain extender may be at least one selected from ethylene glycol, propylene glycol, trimethylol propane, and 1,4-cyclohexane dimethanol. The use amount is preferably 1 to 2% by weight, and less than 1% by weight, the improvement in chemical resistance is small when used, and if it is used in an amount exceeding 2% by weight, problems may arise that viscosity is increased and manufacture is difficult.

The present invention also provides an aqueous dispersion-coated polyurethane resin having a core and a shell structure prepared by the above-described method. The water dispersed polyurethane resin of the present invention has a core and a shell structure, wherein an outer shell is composed of a polyurethane resin, and an inner core is composed of an oligomer containing silane. The silylated polyurethane resin produced according to the method of the present invention can obtain the effect of greatly improving the water resistance, chemical resistance, mechanical properties and storage stability.

In an embodiment of the present invention, a step of reacting an isocyanate with a polyol to form an NCO prepolymer prior to the synthesis of the water-dispersed polyurethane resin, and capping the reactive silane in the prepolymer to prepare a silylated urethane oligomer . Then, a water dispersed silylated polyurethane resin was prepared using the silylated urethane oligomer prepared earlier. The water dispersed polyurethane resin thus synthesized has a core and a shell structure. The outer shell is composed of a polyurethane resin. The inner core is composed of an oligomer containing silane.

The water dispersed polyurethane resin of the present invention has a core and a shell structure, wherein an outer shell is composed of a polyurethane resin, an inner core is composed of an oligomer containing silane, and has high water dispersibility . Also, the silylated polyurethane resin produced according to the method of the present invention can obtain the effect of greatly improving the water resistance, chemical resistance, mechanical properties, and storage stability.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention, but the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

Example 1 Preparation of Silyl Related Urethane Oligomer Resin

A silylated urethane oligomer resin was first synthesized in order to prepare an aqueous dispersed polyurethane resin having a core and shell structure of the present invention.

177.46 g of ester polyol (Mw.2000) was added to a four-neck round bottom flask equipped with a nitrogen inlet, a reflux tube, a thermometer and a stirrer in the composition ratio shown in Table 1, . Next, 31.36 g of isophorone diisocyanate was added and the urethane reaction was maintained for 3 hours to prepare a prepolymer having an NCO group at the terminal.

23.18 g of aminopropyltrimethoxysilane as a reactive silane was mixed and stirred while maintaining the temperature of the reactor at 75 占 폚 to prepare a silylated urethane oligomer resin first.

<Examples 2 and 3> Preparation of Silyl Related Urethane Oligomer Resin

A silylated urethane oligomer resin was prepared in the same manner as in Example 1 except that the content of aminopropyltrimethoxysilane as a reactive silane was changed as shown in Table 1 below.

&Lt; Comparative Example 1 > Produce

As shown in the following Table 1, urethane oligomer resin was prepared in the same manner as in Example 1, except that aminopropyltrimethoxysilane, which is a reactive silane, was not added.

division
Example (Unit: wt%)
Example 1
Example 2
Example 3
Comparative Example 1
Isophorone diisocyanate

13.5
17.0
20.5
10.0
Polyester polyol
(Mw. 1000)
76.5
63.0
49.5
90.0
Aminopropyltrimethoxysilane
(APTMS)
10.0
20.0
30.0
0

<Example 5> Preparation of a water-dispersed thread-supported polyurethane resin having a core and a shell structure

Using the silylated urethane oligomer resin prepared in Example 1, a core-shell structure-modified polyurethane resin was prepared.

A round bottom flask equipped with a nitrogen inlet, a reflux tube, a thermometer and a stirrer was charged with 190.05 g of a polycarbonate polyol (Mw.2000), 15.3 g of dimethylolpropionic acid, 20 g of N-methylpyrrolidone After adding 49.3 g of money, the mixture was heated to 80 DEG C under stirring and kept at this temperature for 1 hour. Next, 84.65 g of dicyclohexylmethane diisocyanate was added and the urethane reaction was maintained for 3 hours to prepare a prepolymer having an NCO group at the terminal. The silylated urethane oligomer prepared in Example 1 was added to the reactor while maintaining the temperature of the reactor at 75 캜 and maintained for 30 minutes. Thereafter, 11.55 g of triethylamine as a neutralizing agent was added thereto while the reaction temperature was lowered to 50 캜, and the reaction was carried out for 1 hour. While stirring at 1,000 rpm, 595 g of distilled water was slowly added thereto to disperse water.

In this way, a water-dispersed thread-bonded polyurethane resin having a core and shell structure in the form of particles was prepared.

&Lt; Examples 6 to 7 > Preparation of water-dispersed threaded polyurethane resin having core and shell structure

Using the silylated urethane oligomers prepared in Examples 2 to 3, a water dispersed polyurethane resin having a core and a shell structure in the form of particles was prepared in the same manner as in Example 5 (Table 2).

Comparative Example 2 Production of water-dispersible polyurethane resin without reactive silane

Using the urethane oligomer prepared in Comparative Example 1, a water-dispersed polyurethane resin having a core and shell structure in the form of particles was prepared in the same manner as in Example 5 (Table 2).

&Lt; Comparative Examples 3 and 4 & gt ; Preparation of a water-dispersed thread-bonded polyurethane resin having core and shell structure without using a silylated urethane oligomer

Instead of the silylated urethane oligomers according to Examples 1 to 4 of the present invention, aminopropyltrimethoxysilane, which is a conventional silane, was added. An aqueous dispersion-coated polyurethane resin was prepared in the same manner as in Example 5 except that the content of the reactive silane was changed.

division
Example (unit: g)
Comparative Example (Unit: g)
Example 5
Example 6
Example 7
Comparative Example 2
Comparative Example 3
Comparative Example 4
Dicyclohexylmethane diisocyanate
84.65
84.65
84.65
84.65
84.65
84.65
Polycarbonate polyol
(Mw 2000)
190.05
190.05
190.05
190.05
190.05
190.05
Dimethylolpropionic acid
15.3
15.3
15.3
15.3
15.3
15.3
Aminopropyltrimethoxysilane
(APTMS)
-
-
-
-
10.8
16.1
Silicylated urethane oligomer
(Example 1)
53.94
-
-
-
-
-
Silicylated urethane oligomer
(Example 2)
-
53.94
-
-
-
-
Silicylated urethane oligomer
(Example 3)
-
-
53.94
-
-
-
Silicylated urethane oligomer
(Comparative Example 1)
-
-
-
53.94
-
-
N-methylpyrrolidone
49.3
49.3
49.3
49.3
49.3
49.3
Triethylamine
11.55
11.55
11.55
11.55
11.55
11.55

< Experimental Example  1> Property test

Each of the core and shell-structured water-dispersed polyurethane resins prepared in the above Examples and Comparative Examples was coated on a glass plate with a wet thickness of 90. The mixture was heated at 120 DEG C for 30 minutes and then dried at room temperature for 3 hours to prepare a coating film. The coating film prepared above was tested for dispersion stability, chemical resistance and film hardness by the following methods, and the results are shown in Table 3 below.

 [Experimental Method]

1. Particle Size (Dispersion Stability): The nano-sized particle size using laser diffraction was measured with a Beckman coulter LS 13 320 (Laser Diffraction particle size analyzer).

2. Ethanol rubbing test: A 500 g load was applied to a gauzed metal weight wrung onto ethanol, and the reciprocating motion was carried out on the film, and the number of times of the number of times of the number of times of passage until the coat completely disappeared was measured.

3. Internal hot-water test: After immersing in water at 100 ° C for 1 hour, the state of the coating film was visually observed.

 : Good transparency and gloss and no change in appearance

 : Some stains occur but generally good

 : Overall turbidity progression and excessive swelling progression

4. Corrosion resistance: A resin composition was applied to the top of the sample using a continuous roll coating simulator on an electrogalvanized steel sheet (EG), and dried at a PMT condition of 180 ° C. The adhesion amount of the film was 1,000 mg / m 2.

The evaluation was carried out by a salt water spray test according to JIS-Z2371 for 8 hours, and the degree of smell was evaluated according to the following criteria.

 ○: Less than 10% of white rye

 B: Less than 30% of white rye

 ×: 30% or more of white rye

5. Surface hardness: The hardness of the surface was measured according to the film strength measurement method by KSM ISO15184 paint and varnish pencil tester, and the general measurement value showing the surface hardness is shown.

Hardness measurement values show high hardness in the order of 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H and 6H.

division
Example
Comparative Example
Example 5
Example 6
Example 7
Comparative Example 2
Comparative Example 3
Comparative Example 4
Particle size
82
84
87
83
91
Poor dispersion
Not measurable
Ethanol rubbing test
25 times
55 times
120 times
15 times
30 times
-
My hot water test
△
△
○
×
△
-
Corrosion resistance
△
△
○
×
△
-
Surface hardness
4B
3B
B
5B
3B
-

It can be seen from the above Table 3 that the water-dispersible, silylated polyurethane resin of the core and shell structure of the present invention is superior in particle stability, chemical resistance (ethanol rubbing, heat resistance and corrosion resistance) and surface hardness there was.

Claims (7)

a) preparing a prepolymer having a terminal NCO group by urethane reaction of a polyol and an isocyanate;
b) preparing a silylated urethane oligomer resin represented by the following formula (2) by mixing at least one reactive silane represented by the following formula (1) in the terminal NCO group of the prepolymer;
[Chemical Formula 1]

(In the formula (1), R ₁ represents an alkyl group or an acetyl group of C ₁ -C ₄ , and X represents an amino group.)
(2)

Wherein R ₂ represents a hydrocarbon backbone of the polyol, R ₃ represents a hydrocarbon skeleton of the isocyanate, and X represents a substituent of the amino group.
c) adding a polyol and a hydrophilic polyol to the isocyanate to prepare a prepolymer having a terminal NCO group;
d) mixing the prepolymer of step c) with the silylated urethane oligomer of formula 2;
e) adding a neutralizing agent to the mixture of step d), followed by water dispersion in ionized water or distilled water; And
f) adding a chain extender to effect a chain extension reaction;
Containing polyurethane resin having a core and a shell structure. The water dispersion chamber relay of claim 1, wherein the isocyanate is at least one selected from the group consisting of toluene diisocyanate, hexamethyl diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate. Wherein the polyurethane resin is a polyurethane resin. The method of claim 1, wherein the polyol is selected from the group consisting of polycarbonate diols, polyoxyethylene glycols, polyoxypropylene glycols, ester polyols, polyether polyols containing polytetramethylene glycol, and polyols derived from castor oil By weight based on the weight of the polyurethane resin. The hydrophilic polyol according to claim 1, wherein the hydrophilic polyol is selected from the group consisting of dimethylol propionic acid, dimethylol butanoic acid, polyoxyethylene glycol, polycaprolactone glycol having a carboxyl group in a side chain, polyether glycol having a sulfonic acid group in a side chain, A polyoxyethylene group substituted with an alkoxy group, and a polyoxyethylene group substituted with an alkoxy group. delete In the production of the silylated urethane oligomer resin of claim 1, the isocyanate is contained in an amount of 10 to 30% by weight based on the total weight of the silylated urethane oligomer resin, Wherein the reactive silane is contained in an amount of 10 to 40% by weight based on the total weight of the resin, and the reactive silane is contained in an amount of 10 to 40% by weight based on the total weight of the resin. A water dispersed polyurethane resin having a core and shell structure prepared by the method of any one of claims 1 to 6.