WATERBORNE AMINO BAKING VARNISH AND METHOD FOR PREPARING THE SAME

Abstract

The waterborne amino baking varnish is prepared with raw materials in percent by weight comprising: 25-40% of a waterborne polyurethane, 4-5% of a waterborne epoxy resin, 7-10% of a waterborne amino resin, 25-35% of deionized water, 1.5-2.5% of a pH regulator, 0.3-0.5% of a wetting agent, 0.2-0.6% of a defoamer, 0.5-1% of a dispersant, 1-5% of a cosolvent, 10-20% of a pigment and a filler, 2-5% of nano-alumina, 0.3-0.5% of lithium magnesium silicate, 0.3-0.5% of a thickener, and 0.5-0.8% of a leveling agent.

Claims

1. A waterborne amino baking varnish, prepared with raw materials in percent by weight comprising: 25-40% of a waterborne polyurethane, 4-5% of a waterborne epoxy resin, 7-10% of a waterborne amino resin, 25-35% of deionized water, 1.5-2.5% of a pH regulator, 0.3-0.5% of a wetting agent, 0.2-0.6% of a defoamer, 0.5-1% of a dispersant, 1-5% of a cosolvent, 10-20% of a pigment and a filler, 2-5% of nano-alumina, 0.3-0.5% of lithium magnesium silicate, 0.3-0.5% of a thickener, and 0.5-0.8% of a leveling agent; wherein the waterborne amino baking varnish is prepared by mixing and uniformly stirring the raw materials; and wherein the waterborne epoxy resin is synthesized by polymerization of a low iodine value fatty acid and an epoxy resin whereby forming a fatty acid-modified epoxy resin having a secondary hydroxyl group, and the fatty acid-modified epoxy resin having the secondary hydroxyl group has an acid value of 5 mgKOH/g.

2. The waterborne amino baking varnish of claim 1, wherein the waterborne polyurethane is obtained by copolymerizing a waterborne branched polyester resin and glycidyl tertiary carboxylic ester, and the waterborne polyurethane has an acid value of 40 to 50 mgKOH/g.

3. The waterborne amino baking varnish of claim 2, wherein a process for preparing the waterborne polyurethane comprises: adding glycidyl tertiary carboxylic ester to the waterborne branched polyester resin with an acid value of 50-60 mgKOH/g, performing copolymerization at 120-150 C. until an end point acid value reaches 40-50 mgKOH/g, whereby obtaining the waterborne polyurethane.

4. The waterborne amino baking varnish of claim 3, wherein a weight ratio of the waterborne branched polyester resin to glycidyl tertiary carboxylic ester is 8.5-9:1.

5. The waterborne amino baking varnish of claim 1, wherein a process for preparing the waterborne epoxy resin comprises: polymerizing the low iodine value fatty acid and the epoxy resin at a temperature of 100-120 C. until an end point acid value reaches 5 mgKOH/g, whereby forming the fatty acid-modified epoxy resin having the secondary hydroxyl group.

6. The waterborne amino baking varnish of claim 5, wherein a weight ratio of the epoxy resin to the low iodine value fatty acid is 2-2.5:1, and an iodine value of the low iodine value fatty acid is 70 g/100 g.

7. The waterborne amino baking varnish of claim 1, wherein the wetting agent is a wetting agent comprising a polyether modified polysiloxane; the defoamer is a defoamer comprising a polyether modified siloxane copolymer containing fumed silica; the dispersant is an anionic compound of a polyether phosphate; the cosolvent is one or two selected from the group consisting of dipropylene glycol methyl ether and ethylene glycol monobutyl ether; the thickener comprises a non-ionic associative polyurethane thickener and an acrylic acid-acrylic ester copolymer alkali swelling thickener; and the leveling agent is a high molecular weight polydimethylsiloxane emulsion.

8. A method for preparing the waterborne amino baking varnish claim 1, comprising the following steps: 1) adding the waterborne polyurethane, the deionized water, the pH regulator, the wetting agent, the defoamer according to the proportion to a paint dispenser and stirring; 2) adding the dispersant, the pigment and the filler, lithium magnesium silicate, nano-alumina, and stirring; 3) adding the cosolvent and stirring; and 4) adding the waterborne amino resin, the waterborne epoxy resin, the leveling agent, and the defoamer, and stirring, measuring an initial viscosity, adding the thickener according to the initial viscosity to regulate a viscosity to 80-90 KU which is measured by a Stormer viscometer at 25 C., whereby obtaining the waterborne amino baking varnish.

9. The method for preparing the waterborne amino baking varnish of claim 8, comprises the following steps: 1) respectively adding the waterborne polyurethane, the deionized water, the pH regulator, the wetting agent, and the defoamer according to the proportion to the paint dispensor, and stirring at a velocity of 800-1000 rpm; 2) adding the dispersant, the pigment and filler, lithium magnesium silicate, and nano-alumina and stirring at a velocity of 1000-1200 rpm for 20 min, wherein a grinding fineness is 15 m; 3) adding the cosolvent and stirring at the velocity of 1000-1200 rpm for 10 min; and 4) respectively adding the waterborne amino resin, the waterborne epoxy resin, the leveling agent, and the defoamer and stirring at a velocity of 600-800 rpm, measuring the initial viscosity, adding the thickener according to the initial viscosity to regulate the viscosity to 80-90 KU which is measured by the Stormer viscometer at 25 C., whereby obtaining the waterborne amino baking varnish.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present application is described in further details in combination with specific embodiments.

Example 1

[0033] A waterborne amino baking varnish was prepared with raw materials in percent by weight comprising: 25% of a waterborne polyurethane, 5% of a waterborne epoxy resin, 9% of a waterborne amino resin, 35% of deionized water, 2% of a pH regulator, 0.3% of a wetting agent, 0.4% of a defoamer, 0.5% of a dispersant, 2% of a cosolvent, 17.1% of a pigment and a filler, 2% of nano-alumina, 0.5% of lithium magnesium silicate, 0.4% of a thickener, and 0.8% of a leveling agent.

[0034] A preparation process of the waterborne polyurethane was conducted as follows: glycidyl tertiary carboxylic ester was added to the waterborne branched polyester resin with an acid value of 50 mgKOH/g, copolymerization was performed at 120 C. for 0.5 hr until an end point acid value reached 40 mgKOH/g, thereby obtaining the waterborne polyurethane. A weight ratio of the waterborne branched polyester resin to glycidyl tertiary carboxylic ester was 8.5:1.

[0035] A preparation process of the waterborne epoxy resin was conducted as follows: the low iodine value fatty acid and the epoxy resin were polymerized at a temperature of 120 C. for 2 hrs until an end point acid value reaches 5 mgKOH/g, thereby forming the fatty acid-modified epoxy resin having the secondary hydroxyl group. A weight ratio of the epoxy resin to the low iodine value fatty acid was 2.2:1, and an iodine value of the low iodine value fatty acid is 70 g/100 g.

[0036] The wetting agent was a wetting agent comprising a polyether modified polysiloxane. The defoamer was a defoamer comprising a polyether modified siloxane copolymer containing fumed silica. The dispersant was an anionic compound of a polyether phosphate. The cosolvent was dipropylene glycol methyl ether. The thickener included a non-ionic associative polyurethane thickener and an acrylic acid-acrylic ester copolymer alkali swelling thickener (a weight ratio of the non-ionic associative polyurethane thickener and the acrylic acid-acrylic ester copolymer alkali swelling thickener was 2:1). The leveling agent was a high molecular weight polydimethylsiloxane emulsion.

[0037] The method for preparing the waterborne amino baking varnish included the following steps:

[0038] 1) the waterborne polyurethane, the deionized water, the pH regulator, the wetting agent, and the defoamer according to the proportion were respectively added to a paint dispensor, and stirred at a velocity of 800-1000 rpm;

[0039] 2) the dispersant, the pigment and filler, lithium magnesium silicate, and nano-alumina were added and stirred at a velocity of 1000-1200 rpm for 20 min, and a grinding fineness was 15 m;

[0040] 3) the cosolvent was added and stirred at the velocity of 1000-1200 rpm for 10 min; and

[0041] 4) the waterborne amino resin, the waterborne epoxy resin, the leveling agent, and the defoamer were respectively added to the paint dispenser and stirred at a velocity of 600-800 rpm, an initial viscosity was then measured. According to the initial viscosity, the thickener was added to regulate the viscosity to 80-90 KU, which was measured by a Stormer viscometer at 25 C., thereby obtaining the waterborne amino baking varnish.

Example 2

[0042] A waterborne amino baking varnish was prepared with raw materials in percent by weight comprising: 30% of a waterborne polyurethane, 4% of a waterborne epoxy resin, 7% of a waterborne amino resin, 28.8% of deionized water, 1.5% of a pH regulator, 0.4% of a wetting agent, 0.2% of a defoamer, 0.7% of a dispersant, 1% of a cosolvent, 20% of a pigment and a filler, 5% of nano-alumina, 0.4% of lithium magnesium silicate, 0.3% of a thickener, and 0.7% of a leveling agent.

[0043] A preparation process of the waterborne polyurethane was conducted as follows: glycidyl tertiary carboxylic ester was added to the waterborne branched polyester resin with an acid value of 60 mgKOH/g, copolymerization was performed at 130 C. for 0.5 hr until an end point acid value reached 50 mgKOH/g, thereby obtaining the waterborne polyurethane. A weight ratio of the waterborne branched polyester resin to glycidyl tertiary carboxylic ester was 9:1.

[0044] A preparation process of the waterborne epoxy resin was conducted as follows: the low iodine value fatty acid and the epoxy resin were polymerized at a temperature of 100 C. for 3 hrs until an end point acid value reaches 4 mgKOH/g, thereby forming the fatty acid-modified epoxy resin having the secondary hydroxyl group. A weight ratio of the epoxy resin to the low iodine value fatty acid was 2.5:1, and an iodine value of the low iodine value fatty acid is 70 g/100 g.

[0045] The wetting agent was a wetting agent comprising a polyether modified polysiloxane. The defoamer was a defoamer comprising a polyether modified siloxane copolymer containing fumed silica. The dispersant was an anionic compound of a polyether phosphate. The cosolvent was ethylene glycol monobutyl ether. The thickener included a non-ionic associative polyurethane thickener and an acrylic acid-acrylic ester copolymer alkali swelling thickener (a weight ratio of the non-ionic associative polyurethane thickener and the acrylic acid-acrylic ester copolymer alkali swelling thickener was 2:1). The leveling agent was a high molecular weight polydimethylsiloxane emulsion.

[0046] The preparation process of the waterborne amino baking varnish was the same as that of Example 1.

Example 3

[0047] A waterborne amino baking varnish was prepared with raw materials in percent by weight comprising: 35% of a waterborne polyurethane, 4.5% of a waterborne epoxy resin, 10% of a waterborne amino resin, 26% of deionized water, 2.5% of a pH regulator, 0.3% of a wetting agent, 0.5% of a defoamer, 0.8% of a dispersant, 5% of a cosolvent, 11% of a pigment and a filler, 3% of nano-alumina, 0.3% of lithium magnesium silicate, 0.5% of a thickener, and 0.6% of a leveling agent.

[0048] A preparation process of the waterborne polyurethane was conducted as follows: glycidyl tertiary carboxylic ester was added to the waterborne branched polyester resin with an acid value of 55 mgKOH/g, copolymerization was performed at 140 C. for 0.5 hr until an end point acid value reached 45 mgKOH/g, thereby obtaining the waterborne polyurethane. A weight ratio of the waterborne branched polyester resin to glycidyl tertiary carboxylic ester was 8.8:1.

[0049] A preparation process of the waterborne epoxy resin was conducted as follows: the low iodine value fatty acid and the epoxy resin were polymerized at a temperature of 110 C. for 2.5 hrs until an end point acid value reaches 3 mgKOH/g, thereby forming the fatty acid-modified epoxy resin having the secondary hydroxyl group. A weight ratio of the epoxy resin to the low iodine value fatty acid was 2:1, and an iodine value of the low iodine value fatty acid is 70 g/100 g.

[0050] The wetting agent was a wetting agent comprising a polyether modified polysiloxane. The defoamer was a defoamer comprising a polyether modified siloxane copolymer containing fumed silica. The dispersant was an anionic compound of a polyether phosphate. The cosolvent was two selected from the group consisting of dipropylene glycol methyl ether and ethylene glycol monobutyl ether (a weight ratio of dipropylene glycol methyl ether to ethylene glycol monobutyl ether was 1:1). The thickener included a non-ionic associative polyurethane thickener and an acrylic acid-acrylic ester copolymer alkali swelling thickener (a weight ratio of the non-ionic associative polyurethane thickener and the acrylic acid-acrylic ester copolymer alkali swelling thickener was 2:1). The leveling agent was a high molecular weight polydimethylsiloxane emulsion.

[0051] The preparation process of the waterborne amino baking varnish was the same as that of Example 1.

Example 4

[0052] A waterborne amino baking varnish was prepared with raw materials in percent by weight comprising: 40% of a waterborne polyurethane, 4.9% of a waterborne epoxy resin, 8% of a waterborne amino resin, 25% of deionized water, 1.5% of a pH regulator, 0.5% of a wetting agent, 0.6% of a defoamer, 1% of a dispersant, 3% of a cosolvent, 10% of a pigment and a filler, 4% of nano-alumina, 0.5% of lithium magnesium silicate, 0.5% of a thickener, and 0.5% of a leveling agent.

[0053] A preparation process of the waterborne polyurethane was conducted as follows: glycidyl tertiary carboxylic ester was added to the waterborne branched polyester resin with an acid value of 50 mgKOH/g, copolymerization was performed at 150 C. for 0.5 hr until an end point acid value reached 42 mgKOH/g, thereby obtaining the waterborne polyurethane. A weight ratio of the waterborne branched polyester resin to glycidyl tertiary carboxylic ester was 8.7:1.

[0054] A preparation process of the waterborne epoxy resin was conducted as follows: the low iodine value fatty acid and the epoxy resin were polymerized at a temperature of 120 C. for 3 hrs until an end point acid value reaches 2 mgKOH/g, thereby forming the fatty acid-modified epoxy resin having the secondary hydroxyl group. A weight ratio of the epoxy resin to the low iodine value fatty acid was 2.4:1, and an iodine value of the low iodine value fatty acid is 70 g/100 g.

[0055] The wetting agent was a wetting agent comprising a polyether modified polysiloxane. The defoamer was a defoamer comprising a polyether modified siloxane copolymer containing fumed silica. The dispersant was an anionic compound of a polyether phosphate. The cosolvent was dipropylene glycol methyl ether. The thickener included a non-ionic associative polyurethane thickener and an acrylic acid-acrylic ester copolymer alkali swelling thickener (a weight ratio of the non-ionic associative polyurethane thickener and the acrylic acid-acrylic ester copolymer alkali swelling thickener was 2:1). The leveling agent was a high molecular weight polydimethylsiloxane emulsion.

[0056] The preparation process of the waterborne amino baking varnish was the same as that of Example 1.

[0057] The above waterborne amino baking varnish prepared by the above method of the present application was tested, and the technical indicators were measured as follows:

TABLE-US-00001 Hardness 2H (pencil hardness test), Gloss 98 (60 angle test), Adhesion 1 level (cross-cut test 1 mm), Stability 30 d (50 C. storage), Water resistance 240 h, and Impact Level 1 (100 cm).

[0058] The waterborne amino baking varnish of the present application features waterborne, environmental protection, good stability, high hardness, being applicable to multiple coating processes, strong adhesion, fast drying, strong gloss retention, excellent aging resistance, good water resistance, convenient for construction, low cost, non-combustible, non-explosive, pollution-free, low-temperature storage, and non-deterioration. It also has the characteristics of convenient and quick construction, plain and smooth paint film, and good hand feeling.

[0059] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.