A waterborne automobile coating composition and a preparing method and applications thereof

Abstract

A waterborne automobile coating composition is provided. The composition is prepared from, by weight, 20-60 parts of a waterborne polyurethane dispersoid, 1.0-3.5 parts of a dispersing agent, 5-15 parts of titanium dioxide, 5-15 parts of precipitated barium sulfate, 0.1-0.5 part of carbon black, 0.5-1.5 parts of a defoamer, 3-8 parts of a waterborne hydroxy acrylic acid dispersoid, 0.1-0.5 part of an organic amine, 6-12 parts of amino resin, 0.1-1 part of a substrate wetting agent, 1-3 parts of an explosion-proof auxiliary agent, 1-5 parts of a cosolvent, 20-40 parts of deionized water and 0.1-1 part of a thickening agent. The waterborne polyurethane dispersoid is a compound of a polycarbonate-type waterborne polyurethane dispersoid having hydroxy groups and a polyester-type waterborne polyurethane dispersoid preferably. The coating composition has excellent resistance to rock crash, and can meet requirements on an automobile coating process including three times of coating and one time of baking, namely a 3C1B process, in the field of environment protection.

Description

technical field

[0001] The invention relates to a water-based automotive intermediate coating composition, which belongs to the field of coating application. Background technique

[0002] The traditional automobile intermediate coating (commonly known as surfacer) is solvent-based and contains a large amount of organic solvents, which will generate a large amount of VOC during the construction and drying process; the construction process generally adopts the 3C2B process, that is, the automobile intermediate coating After the layer is completely dried and cured, paint and finish varnish are sprayed, and the film thickness of the middle coat reaches 30-40um, and finally baked at 140°C for 20-30 minutes to achieve curing.

[0003] In recent years, with the gradual strengthening of environmental protection requirements and the promulgation of national environmental protection regulations, water-based coatings have become one of the development directions of future coatings, and...

Examples

Embodiment 1

[0074] Preparation of polycarbonate polyurethane dispersion 1: 189 parts of polycarbonate polyol 980R (parts by weight, the same below), 7.2 parts of dimethylolpropionic acid DMPA, 3 parts of trimethylolpropane TMP and 4,4' -Add 42 parts of dicyclohexylmethane diisocyanate HMDI into the reaction bottle, react at 80~120°C to the end point, add an appropriate amount of solvent (such as acetone, methyl ethyl ketone) to reduce the viscosity, then lower the temperature to below 40°C and add 4.52 parts of triethanolamine TEA Neutralize, then add deionized water to disperse under strong stirring, adjust the solid content after removing the solvent, the solid content is 35%, and the hydroxyl content is about 1%. Based on the weight of the solid components in the dispersion, the weight average molecular weight is about 10000 Polycarbonate Polyurethane Dispersion 1.

Embodiment 2

[0076] Preparation of polycarbonate polyurethane dispersion 2: 189 parts of polycarbonate polyol 980R, 7.8 parts of dimethylolpropionic acid DMPA, 4.8 parts of trimethylolpropane TMP and 4,4'-dicyclohexylmethane diisocyanate HMDI42 Add 5.88 parts of triethanolamine TEA to neutralize after cooling down to below 40 ℃, and then stir vigorously Add deionized water to disperse, and adjust the solid content after removing the solvent to obtain a polycarbonate polyurethane dispersion 2 with a hydroxyl content of 2%, a solid content of 35%, and a weight average molecular weight of about 15,000.

Embodiment 3

[0078] Preparation of polycarbonate polyurethane dispersion 3: 150 parts of polycarbonate polyol 980R, 7.0 parts of dimethylolpropionic acid DMPA, 7.5 parts of trimethylolpropane TMP and 4,4'-dicyclohexylmethane diisocyanate HMDI Add 42 parts into the reaction bottle, react at 80-120°C to the end, add an appropriate amount of solvent (such as acetone, methyl ethyl ketone) to reduce the viscosity, then cool down to below 40°C, add 5.28 parts of triethanolamine TEA to neutralize, and then Add deionized water to disperse under stirring, and adjust the solid content after removing the solvent to obtain a polycarbonate polyurethane dispersion 3 with a hydroxyl content of 3%, a solid content of 35%, and a weight average molecular weight of 3000.

technical field

[0001] The invention relates to a water-based automotive intermediate coating composition, which belongs to the field of coating application. Background technique

[0002] The traditional automobile intermediate coating (commonly known as surfacer) is solvent-based and contains a large amount of organic solvents, which will generate a large amount of VOC during the construction and drying process; the construction process generally adopts the 3C2B process, that is, the automobile intermediate coating After the layer is completely dried and cured, paint and finish varnish are sprayed, and the film thickness of the middle coat reaches 30-40um, and finally baked at 140°C for 20-30 minutes to achieve curing.

[0003] In recent years, with the gradual strengthening of environmental protection requirements and the promulgation of national environmental protection regulations, water-based coatings have become one of the development directions of future coatings, and...

Examples

Embodiment 1

[0074] Preparation of polycarbonate polyurethane dispersion 1: 189 parts of polycarbonate polyol 980R (parts by weight, the same below), 7.2 parts of dimethylolpropionic acid DMPA, 3 parts of trimethylolpropane TMP and 4,4' -Add 42 parts of dicyclohexylmethane diisocyanate HMDI into the reaction bottle, react at 80~120°C to the end point, add an appropriate amount of solvent (such as acetone, methyl ethyl ketone) to reduce the viscosity, then lower the temperature to below 40°C and add 4.52 parts of triethanolamine TEA Neutralize, then add deionized water to disperse under strong stirring, adjust the solid content after removing the solvent, the solid content is 35%, and the hydroxyl content is about 1%. Based on the weight of the solid components in the dispersion, the weight average molecular weight is about 10000 Polycarbonate Polyurethane Dispersion 1.

Embodiment 2

[0076] Preparation of polycarbonate polyurethane dispersion 2: 189 parts of polycarbonate polyol 980R, 7.8 parts of dimethylolpropionic acid DMPA, 4.8 parts of trimethylolpropane TMP and 4,4'-dicyclohexylmethane diisocyanate HMDI42 Add 5.88 parts of triethanolamine TEA to neutralize after cooling down to below 40 ℃, and then stir vigorously Add deionized water to disperse, and adjust the solid content after removing the solvent to obtain a polycarbonate polyurethane dispersion 2 with a hydroxyl content of 2%, a solid content of 35%, and a weight average molecular weight of about 15,000.

Embodiment 3

[0078] Preparation of polycarbonate polyurethane dispersion 3: 150 parts of polycarbonate polyol 980R, 7.0 parts of dimethylolpropionic acid DMPA, 7.5 parts of trimethylolpropane TMP and 4,4'-dicyclohexylmethane diisocyanate HMDI Add 42 parts into the reaction bottle, react at 80-120°C to the end, add an appropriate amount of solvent (such as acetone, methyl ethyl ketone) to reduce the viscosity, then cool down to below 40°C, add 5.28 parts of triethanolamine TEA to neutralize, and then Add deionized water to disperse under stirring, and adjust the solid content after removing the solvent to obtain a polycarbonate polyurethane dispersion 3 with a hydroxyl content of 3%, a solid content of 35%, and a weight average molecular weight of 3000.

Images