HYDROPHILIC ACRYLIC-MODIFIED POLYURETHANE AND METHOD FOR PREPARING SAME, AND WATER-BASED PAINT COMPOSITION PREPARED THEREFROM AND MANUFACTURING METHOD THEREOF

Abstract

The present invention relates to a hydrophilic acrylic-modified polyurethane and a method for preparing same, and a water-based paint composition using same and a manufacturing method thereof and, more specifically, to a hydrophilic acrylic-modified polyurethane and a method for preparing same, and a water-based paint composition using same and a manufacturing method thereof, the hydrophilic acrylic-modified polyurethane comprising: a polymerization unit derived from an anhydrosugar alcohol-alkylene oxide adduct; a polymerization unit derived from polyisocyanate; and a polymerization unit derived from hydroxyalkyl (meth)acrylate, and capable of providing a water-based paint composition in which eco-friendliness, adhesiveness (adhesion), crack resistance and water resistance are all improved.

Claims

1. A hydrophilic acryl-modified polyurethane comprising: polymerized units derived from anhydrosugar alcohol-alkylene oxide adduct; polymerized units derived from polyisocyanate; and polymerized units derived from hydroxyalkyl (meth)acrylate.

2. The hydrophilic acryl-modified polyurethane of claim 1, wherein the anhydrosugar alcohol-alkylene oxide adduct is an adduct obtained by reacting hydroxyl group(s) at both ends or one end of anhydrosugar alcohol with alkylene oxide, and wherein the alkylene oxide is a linear alkylene oxide having 2 to 8 carbons or a branched alkylene oxide having 3 to 8 carbons.

3. The hydrophilic acryl-modified polyurethane of claim 2, wherein the anhydrosugar alcohol is isosorbide, isomannide, isoidide or a mixture thereof.

4. The hydrophilic acryl-modified polyurethane of claim 1, wherein the anhydrosugar alcohol-alkylene oxide adduct is that prepared by a preparation method comprising the steps of: (1) treating anhydrosugar alcohol with acid component; and (2) conducting addition reaction of the acid-treated anhydrosugar alcohol obtained in said step (1) and alkylene oxide.

5. The hydrophilic acryl-modified polyurethane of claim 1, wherein the polyisocyanate is methylenediphenyl diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or a combination thereof.

6. The hydrophilic acryl-modified polyurethane of claim 1, wherein the hydroxyalkyl (meth)acrylate is 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, or a combination thereof.

7. The hydrophilic acryl-modified polyurethane of claim 1, which is represented by the following formula 2: ##STR00015## in the above formula 2, each of R1 is independently an alkylene group, each of R2 is independently an alkylene group, a cycloalkylene group, or an arylene group, each of R3 is independently an alkylene group, each of R4 is independently a hydrogen atom or an alkyl group, M is a divalent organic group derived from anhydrosugar alcohol, each of m and n independently represents an integer of 0 to 15, and m+n represents an integer of 1 to 30.

8. The hydrophilic acryl-modified polyurethane of claim 7, wherein in the formula 2, each of R1 is independently a C2-C8 linear or C3-C8 branched alkylene group, each of R2 is independently a C2-C20 linear or C3-C20 branched alkylene group, a C3-C20 cycloalkylene group, or a C6-C20 arylene group, each of R3 is independently a C1-C8 linear or C3-C8 branched alkylene group, each of R4 is independently a hydrogen atom or a C1-C4 linear or C3-C4 branched alkyl group, M is a divalent organic group derived from isosorbide, isomannide or isoidide, each of m and n independently represents an integer of 0 to 15, and m+n represents an integer of 1 to 25.

9. A method for preparing a hydrophilic acryl-modified polyurethane, comprising the steps of: (1) reacting anhydrosugar alcohol-alkylene oxide adduct and polyisocyanate to prepare intermediate having terminal isocyanate group; and (2) reacting the intermediate obtained in said step (1) and hydroxyalkyl (meth)acrylate.

10. A waterborne coating composition comprising: a polymer prepared by polymerization reaction of the hydrophilic acryl-modified polyurethane of claim 1 and hydrophilic acryl monomer; and water.

11. The waterborne coating composition of claim 10, wherein the hydrophilic acryl monomer is one or more selected from the group consisting of an acryl monomer having carboxyl group, an amide-based acryl monomer and an acryl monomer having hydroxyl group.

12. The waterborne coating composition of claim 10, wherein the amount of the hydrophilic acryl-modified polyurethane is greater than 30 parts by weight to less than 85 parts by weight, based on 100 parts by weight of the sum of the hydrophilic acryl-modified polyurethane, hydrophilic acryl monomer and water.

13. A method for preparing a waterborne coating composition, comprising a step of conducting polymerization reaction of the hydrophilic acryl-modified polyurethane of claim 1 and hydrophilic acryl monomer, in the presence of water as solvent and polymerization initiator.

Description

EXAMPLES

Preparation of Anhydrosugar Alcohol-Alkylene Oxide Adduct

Preparation Example A1: Preparation of isosorbide-ethylene oxide 5 mole adduct

[0093] 146 g of isosorbide and 0.15 g of phosphoric acid (85%) as an acid component were put into a reactor that could be pressurized, and the inside of the reactor was substituted with nitrogen and heated up to 100° C. and the moisture in the reactor was removed by pressure reduction under vacuum. Then, while firstly adding 88 g of ethylene oxide slowly thereto, the reaction was conducted at 100 to 140° C. for 2 to 3 hours. At that time, the reaction temperature was controlled so as not to exceed 140° C. Thereafter, the inside of the reactor was cooled to 50° C., and then 0.3 g of potassium hydroxide was added to the reactor, the inside of the reactor was substituted with nitrogen and heated up to 100° C. and the moisture in the reactor was removed by pressure reduction under vacuum. Then, while secondly adding 132 g of ethylene oxide slowly thereto, the reaction was conducted at 100 to 140° C. for 2 to 3 hours. After completing the reaction, the inside of the reactor was cooled to 50° C., 4 g of Ambosol MP20 was added thereto, and the inside of the reactor was reheated and agitated at 100° C. to 120° C. for 1 to 5 hours to remove residual metal ions (at that time, the inside of the reactor was substituted with nitrogen and/or pressure reduction under vacuum was carried out). After confirming that no metal ions were detected, the inside of the reactor was cooled to 60° C. to 90° C. and the remaining byproduct was removed to obtain 362 g of isosorbide-ethylene oxide 5 mole adduct in transparent liquid form.

Preparation Example A2: Preparation of Isosorbide-Ethylene Oxide 10 Mole Adduct

[0094] Excepting that the secondly added amount of ethylene oxide was changed from 132 g to 352 g, the same method as Preparation Example A1 was conducted to obtain 551 g of isosorbide-ethylene oxide 10 mole adduct in transparent liquid form.

Preparation Example A3: Preparation of Isosorbide-Propylene Oxide 5 Mole Adduct

[0095] As the raw material for the addition reaction, propylene oxide was used instead of ethylene oxide. Concretely, excepting that 116 g of propylene oxide was firstly added instead of 88 g of ethylene oxide and 174 g of propylene oxide was secondly added instead of 132 g of ethylene oxide, the same method as Preparation Example A1 was conducted to obtain 423 g of isosorbide-propylene oxide 5 mole adduct in transparent liquid form.

Preparation Example A4: Preparation of Isosorbide-Propylene Oxide 10 Mole Adduct

[0096] As the raw material for the addition reaction, propylene oxide was used instead of ethylene oxide. Concretely, excepting that 116 g of propylene oxide was firstly added instead of 88 g of ethylene oxide and 465 g of propylene oxide was secondly added instead of 132 g of ethylene oxide, the same method as Preparation Example A1 was conducted to obtain 698 g of isosorbide-propylene oxide 10 mole adduct in transparent liquid form.

Preparation of Hydrophilic Acryl-Modified Polyurethane

Example A1: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Isosorbide-Ethylene Oxide 5 Mole Adduct as Polyol, Isophorone Diisocyanate (IPDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0097] Into a 3-necked equipped an agitator, 222 g of isophorone diisocyanate (IPDI) and 0.1 g of dibutyltin dilaurate (DBTDL) as reaction catalyst were fed. While agitating the mixture at room temperature, 183 g of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 was added slowly thereto and the crosslinking reaction was conducted. After completing addition of the isosorbide-ethylene oxide 5 mole adduct, the mixture was agitated at 50° C. for 1 hour for aging, and 65 g of 2-hydroxyethyl methacrylate was added slowly thereto and the acryl modification reaction was conducted. After completing addition of 2-hydroxyethyl methacrylate, the mixture was agitated at 50° C. for 1 hour for aging, and the reaction product was cooled to room temperature to obtain 467 g of hydrophilic acryl-modified polyurethane of the following formula 3.

##STR00007##

Example A2: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Isosorbide-Ethylene Oxide 10 Mole Adduct as Polyol, Hexamethylene Diisocyanate (HDI) as Polyisocyanate and 2-Hydroxyethyl Acrylate as Hydroxyalkyl (Meth)Acrylate

[0098] Excepting that 168 g of hexamethylene diisocyanate (HDI) was used instead of isophorone diisocyanate (IPDI) as polyisocyanate, 293 g of the isosorbide-ethylene oxide 10 mole adduct prepared in Preparation Example A2 was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol and 58 g of 2-hydroxyethyl acrylate was used instead of 2-hydroxyethyl methacrylate as hydroxyalkyl (meth)acrylate, the same method as Example A1 was conducted to obtain 515 g of hydrophilic acryl-modified polyurethane of the following formula 4.

##STR00008##

Example A3: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Isosorbide-Propylene Oxide 5 Mole Adduct as Polyol, Methylenediphenyl Diisocyanate (MDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0099] Excepting that 250 g of methylenediphenyl diisocyanate (MDI) was used instead of isophorone diisocyanate (IPDI) as polyisocyanate and 218 g of the isosorbide-propylene oxide 5 mole adduct prepared in Preparation Example A3 was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol, the same method as Example A1 was conducted to obtain 529 g of hydrophilic acryl-modified polyurethane of the following formula 5.

##STR00009##

Example A4: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Isosorbide-Propylene Oxide 10 Mole Adduct as Polyol, Isophorone Diisocyanate (IPDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0100] Excepting that 363 g of the Isosorbide-Propylene Oxide 10 Mole Adduct Prepared in Preparation Example A4 was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol, the same method as Example A1 was conducted to obtain 643 g of hydrophilic acryl-modified polyurethane of the following formula 6.

##STR00010##

Comparative Example A1: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Isosorbide as Polyol, Isophorone Diisocyanate (IPDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0101] Excepting that 146 g of isosorbide was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol, the same method as Example A1 was conducted to obtain 431 g of hydrophilic acryl-modified polyurethane of the following formula 7.

##STR00011##

Comparative Example A2: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Polyethylene Glycol (Number Average Molecular Weight: 500) as Polyol, Isophorone Diisocyanate (IPDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0102] Excepting that 500 g of polyethylene glycol (number average molecular weight: 500) was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol, the same method as Example A1 was conducted to obtain 782 g of hydrophilic acryl-modified polyurethane of the following formula 8.

##STR00012##

Comparative Example A3: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Polypropylene Glycol (Number Average Molecular Weight: 500) as Polyol, Hexamethylene Diisocyanate (HDI) as Polyisocyanate and 2-Hydroxyethyl Acrylate as Hydroxyalkyl (Meth)Acrylate

[0103] Excepting that 168 g of hexamethylene diisocyanate (HDI) was used instead of isophorone diisocyanate (IPDI) as polyisocyanate, 500 g of polypropylene glycol (number average molecular weight: 500, Kumho Petrochemical) was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol and 58 g of 2-hydroxyethyl acrylate was used instead of 2-hydroxyethyl methacrylate as hydroxyalkyl (meth)acrylate, the same method as Example A1 was conducted to obtain 720 g of hydrophilic acryl-modified polyurethane of the following formula 9.

##STR00013##

Comparative Example A4: Preparation of Hydrophilic Acryl-Modified Polyurethane by Using Polytetramethylene Glycol (Number Average Molecular Weight: 1,000) as Polyol, Methylenediphenyl Diisocyanate (MDI) as Polyisocyanate and 2-Hydroxyethyl Methacrylate as Hydroxyalkyl (Meth)Acrylate

[0104] Excepting that 250 g of methylenediphenyl diisocyanate (MDI) was used instead of isophorone diisocyanate (IPDI) as polyisocyanate and 1,000 g of polytetramethylene glycol (number average molecular weight: 1,000, Aldrich) was used instead of the isosorbide-ethylene oxide 5 mole adduct prepared in Preparation Example A1 as polyol, the same method as Example A1 was conducted to obtain 1,308 g of hydrophilic acryl-modified polyurethane of the following formula 10.

##STR00014##

Preparation of Waterborne Coating Composition

Examples B1 to B4 and Comparative Examples B1 to B5: Standard Preparation Method

[0105] Water, potassium persulfate (KPS) as polymerization initiator, hydrophilic acryl-modified polyurethane and acryl monomer were mixed with the weight ratio shown in the following Table 1 and sufficiently agitated by using a high-speed dissolver, and the mixture was heated to 85° C. and agitated, and then the polymerization reaction was conducted sufficiently for 3 hours to prepare the waterborne coating composition of each of Examples B1 to B4 and Comparative Examples B1 to B5.

TABLE-US-00001 TABLE 1 Example Comparative Example Material B1 B2 B3 B4 B1 B2 B3 B4 B5 Hydrophilic acryl-modified Ex. A1 Ex. A2 Ex. A3 Ex. A4 Comp. Comp. Comp. Comp. — polyurethane (60) (40) (80) (50) Ex. A1 Ex. A2 Ex. A3 Ex. A4 (parts by weight) (60) (60) (60) (60) Acryl monomer AA AA AA AA AA AA AA AA AA (5) (10) (5) (5) (5) (5) (5) (5) (25) (parts by weight) HEMA HEMA HEMA HEMA HEMA HEMA HEMA HEMA HEMA (15) (20) (5) (20) (15) (15) (15) (15) (30) AAM AAM AAM AAM AAM AAM AAM AAM AAM (10) (10) (5) (15) (10) (10) (10) (10) (25) Water (parts by weight) 10 20 5 10 10 10 10 10 20 KPS (parts by weight) 0.5 AA: Acrylic acid HEMA: 2-hydroxyethyl methacrylate AAM: Acrylamide KPS: potassium persulfate AA, HEMA, AAM and KPS are those manufactured by Samchun Chemicals.

Evaluation of Properties of the Waterborne Coating Composition

[0106] The waterborne coating composition prepared in each of Examples B1 to B4 and Comparative Examples B1 to B5 was coated on polyvinyl chloride (PVC) film two times and then dried to prepare a test sample comprising polyvinyl chloride film and a coating layer formed on the film. The test sample was evaluated for adhesion, crack resistance and water resistance according to the following methods, and the results are shown in the following Table 2.

Method of Evaluating the Properties

[0107] (1) Adhesion

[0108] According to ASTM D 3359 which is the adhesion test standard for coatings, the coating layer of the test sample was scratched with a cross hatch cutter by crossing lines thereon to make 100 grid pieces with a size of 10 mm×10 mm, and a tape was attached on the grid pieces and rubbed with uniform force, and then the tape was taken off. The number of grid pieces detached from the coating layer of the test sample and adhered to the removed tape was counted. According to the number of grid pieces detached from the coating layer of the test sample, the degree of adhesion was expressed as a grade of from 0B to 5B below. Smaller number of grid pieces detached from the coating layer of the test sample means better adhesion of the coating layer (grade 4B or higher is required).

[0109] [Criteria for Classification of Cross Cut (ASTM D 3359)]

TABLE-US-00002 Grade Criteria 5B No grid piece was detached from the coating layer. 4B 1 to 5 grid pieces were detached from the coating layer. 3B 6 to 15 grid pieces were detached from the coating layer. 2B 16 to 35 grid pieces were detached from the coating layer. 1B 36 to 65 grid pieces were detached from the coating layer. 0B 66 or more grid pieces were detached from the coating layer.

[0110] (2) Crack Resistance

[0111] After repeating 5 times of storage of the test sample in a freezer at −20° C. for 1 hour and then in a hot air dryer at 80° C. for 1 hour, observation was made with the naked eye to confirm whether or not cracks such as breaking, peeling, or splitting of the coating layer of the test sample were generated.

[0112] (3) Water Resistance

[0113] After soaking the test sample in water at room temperature for 72 hours, observation was made with the naked eye to confirm whether or not swelling, cracking, peeling, discoloration, etc. of the coating layer occurred.

TABLE-US-00003 TABLE 2 Example Comparative Example Property B1 B2 B3 B4 B1 B2 B3 B4 B5 Adhesion 5B 4B 4B 5B 4B 4B Phase separation 3B Crack No No No No No Crack (Not applicable) Crack resistance problem problem problem problem problem generation generation Water No No No No Peeling Peeling resistance problem problem problem problem

[0114] As shown in Table 2 above, in case of the waterborne coating compositions of Examples B1 to B4 prepared by using the hydrophilic acryl-modified polyurethane according to the present invention, all of the standard requirements for adhesion, crack resistance and water resistance were achieved. That is, the waterborne coating composition according to the present invention is an eco-friendly paint free of organic solvent and/or surfactant, and has excellent adhesion, crack resistance and water resistance.

[0115] However, in case of Comparative Example B1 using an acryl-modified polyurethane prepared by using anhydrosugar alcohol (ISB), not anhydrosugar alcohol-alkylene oxide adduct, peeling occurred in water at room temperature, resulting in poor water resistance. In addition, in case of the waterborne coating composition of Comparative Example B2 using an acryl-modified polyurethane prepared by using polyethylene glycol (a hydrophilic polyol for general purpose), cracks were generated in the coating layer, and peeling occurred in water at room temperature, resulting in poor water resistance. Furthermore, in case of the waterborne coating compositions of Comparative Examples B3 and B4 using an acryl-modified polyurethane prepared by using polypropylene glycol or polytetramethylene glycol (hydrophilic polyols for general purpose), phase separation occurred within the coating composition, so that the evaluation of properties as waterborne paint was impossible.

[0116] Also, in case of the waterborne coating composition of Comparative Example B5 not using acryl-modified polyurethane itself, the adhesion was insufficient, cracks were generated in the coating layer, and peeling occurred in water at room temperature, resulting in poor water resistance.