CN114806370B - Waterborne polyurethane gloss oil and preparation method and application thereof - Google Patents

Abstract

The invention discloses a water-based polyurethane varnish, a preparation method and application thereof. The composition of the water-based polyurethane varnish of the present invention includes water-based hydroxyacrylate dispersion, hydrophilic modified siloxane hybrid HDI polyisocyanate, hydrophilic modified IPDI polyisocyanate, cosolvent, long-wave leveling agent, short-wave Type leveling agent, substrate wetting agent, defoamer, anti-UV additive, neutralizer, rheology additive and water. The preparation method of the water-based polyurethane varnish of the present invention is very simple, and each component can be uniformly mixed in batches according to the distribution ratio. The water-based polyurethane varnish of the present invention has a long application period, and no agglomeration and settlement will occur when stored at room temperature for a long time. After film formation, the paint film has high gloss, high hardness, strong adhesion, excellent acid and alkali resistance, and water resistance. Excellent performance and broad application prospects.

Description

A kind of aqueous polyurethane varnish and its preparation method and application

technical field

The invention relates to the technical field of industrial coatings, in particular to a water-based polyurethane varnish and a preparation method and application thereof.

Background technique

Water-based two-component polyurethane coatings are a relatively common type of industrial coatings. They have low-temperature film-forming properties, and the formed paint film has the advantages of excellent mechanical properties and excellent chemical resistance. However, due to the content of hydrophilic groups in the coating system Larger, water is easy to penetrate, diffuse and migrate in the paint film, which will eventually lead to whitening, loss of gloss, blistering, and peeling of the paint film.

At present, most of the commercially available water-based two-component polyurethane coatings use sulfonate-modified HDI trimer isocyanate as the curing agent with relatively excellent comprehensive performance, and the comprehensive performance of the paint film with excessive isocyanate groups (-NCO) is required to achieve the best performance. Due to the high activity of -NCO, excessive -NCO in the paint film will inevitably have a side reaction with water to form polyurea (easy to condense and solidify) and carbon dioxide, which will cause the gloss and hardness of the paint film to decrease, and the paint film haze increase, and the paint film is prone to surface defects such as blisters, pinholes, bird's-eyes, and craters, which greatly reduces the pot life of the paint.

Therefore, it is of great significance to develop a water-based polyurethane coating with long pot life, high gloss/hardness/adhesion/excellent acid and alkali resistance/excellent water resistance after film formation.

Contents of the invention

The object of the present invention is to provide a kind of waterborne polyurethane varnish and its preparation method and application.

The technical scheme that the present invention takes is:

A kind of aqueous polyurethane varnish, it comprises the component of following mass percent:

Waterborne hydroxyacrylate dispersion: 45% to 55%;

Hydrophilic modified siloxane hybrid HDI polyisocyanate: 13% to 20%;

Hydrophilic modified IPDI polyisocyanate: 4% to 8%;

Co-solvent: 4% to 8%;

Long-wave leveling agent: 0.3% to 1.0%;

Short-wave leveling agent: 0.1% to 0.3%;

Substrate wetting agent: 0.2% to 0.5%;

Defoamer: 0.1% to 0.4%;

Anti-UV additives: 0.5% to 1.5%;

Neutralizer: 0.05% to 0.2%;

Rheological additives: 0% to 0.5%;

Water: 15% to 20%.

Preferably, the water-based hydroxyacrylate dispersion is at least one of Wanhua 2042, Covestro 2470, allnex 6299W, and Guanzhi 4842.

Preferably, the hydrophilic modified siloxane hybrid HDI polyisocyanate is Guanzhi 9025. Guanzhi 9025 adopts a special siloxane grafting technology, uses a hydrophobic segment structure, has water resistance and early water resistance comparable to traditional solvent-based curing agents, and the curing agent also has the advantages of high gloss and weather resistance .

Preferably, the hydrophilic modified IPDI polyisocyanate is Liangu 3597A. The reactive group activity of Liangu 3597A is low, so that the water-based polyurethane varnish has a long pot life, fast drying speed, and high cross-linking density. In addition, the low viscosity of Liangu 3597A can make the water-based polyurethane varnish film-forming The paint film has high gloss, good fullness and high hardness, which can greatly improve the comprehensive performance of water-based polyurethane varnish.

Preferably, the cosolvent is dipropylene glycol monobutyl ether (DPM), propylene glycol monobutyl ether (PNB), dipropylene glycol monobutyl ether (DPNB), diethylene glycol monobutyl ether (DB), propylene glycol diacetate (PGDA ) at least one of.

Preferably, the long-wave leveling agent is at least one of BYK381, Centron PW336, Mingling LA452, allnex XW395, Dexinli L39, Shangco 3885, and BASF 3772.

Preferably, the short-wave leveling agent is at least one of Tego450, BYK BYK333, BYK BYK3760, BASF 3034, and Dow Corning DC57. Long-wave leveling agent has good compatibility, and can prolong the opening time of paint film channels, and can provide long-wave leveling and post-leveling of paint film, avoiding surface defects such as pinholes and fish eyes. The short-wave leveling agent can reduce the surface tension of the system, provide uniform surface tension for the wet film, eliminate Bernard vortices, prevent shrinkage cavities, and improve leveling. In addition, it can also play the role of increasing slip and scratch resistance. effect. The combination of long-wave leveling agent and short-wave leveling agent will greatly improve the long-wave and short-wave effects of the paint film, that is, the mirror leveling effect.

Preferably, the substrate wetting agent is Evonik 104E, Evonik AD01, Harrox Venadol40, BYK BYK346, BYK BYK3481, Tego Tego270, Tego Tego280, Tego Tego4100, Tego Tego4200 at least one.

Preferably, the defoamer is at least one of Evonik MD20, Evonik DF110D, and Evonik 118.

Preferably, the anti-UV additive is at least one of BASF Tinuvin1130, BASF Tinuvin292, and BASF Tinuvin234.

Preferably, the neutralizing agent is at least one of N,N-dimethylethanolamine (DMEA) and 2-amino-2-methyl-1-propanol (AMP-95).

Preferably, the rheology additive is at least one of Deqian WT105A, BYK BYK425, Mingling PUR62, Adike UH752, and Wanhua U905.

The preparation method of the above-mentioned water-based polyurethane varnish comprises the following steps: after pre-mixing cosolvent, long-wave leveling agent, short-wave leveling agent, substrate wetting agent, defoamer, anti-UV auxiliary agent and neutralizer evenly Add water-based hydroxyacrylate dispersion, then add water, stir well, then add hydrophilic modified siloxane hybrid HDI polyisocyanate and hydrophilic modified IPDI polyisocyanate, stir well, then add rheological additives agent, and stir evenly to obtain water-based polyurethane varnish.

Preferably, the preparation method of the above-mentioned water-based polyurethane varnish includes the following steps: adding water-based hydroxyacrylate into a dispersion container, adjusting the speed of the mixer to 500rpm-800rpm, and dispersing, and then adding a cosolvent, a long-wave leveling agent, and a short-wave flow Leveling agent, substrate wetting agent, defoamer, anti-UV additive and neutralizer are pre-mixed evenly and then slowly added to the aqueous hydroxyacrylate dispersion, then add water, stir evenly, and then add hydrophilic modified silicon Mix oxane hybrid HDI polyisocyanate and hydrophilic modified IPDI polyisocyanate evenly, then adjust the speed of the mixer to 1000rpm ~ 1200rpm, then slowly add rheological additives, stir evenly, let stand, and filter to obtain water-based Polyurethane varnish.

The beneficial effects of the present invention are: the water-based polyurethane varnish of the present invention has a long application period, no agglomeration and settlement will occur when stored at room temperature for a long time, and the paint film after film formation has high gloss, high hardness, strong adhesion, It has excellent acid and alkali resistance and water resistance, and has broad application prospects.

Detailed ways

The present invention will be further explained and illustrated below in conjunction with specific embodiments.

Example 1:

A kind of waterborne polyurethane varnish, its raw material composition is as shown in the following table:

Table 1 A kind of raw material composition table of waterborne polyurethane varnish

The preparation method of above-mentioned waterborne polyurethane varnish comprises the following steps:

Add water-based hydroxyacrylate to the dispersion container, adjust the speed of the mixer to 600rpm, and disperse, and then add co-solvent, long-wave leveling agent, short-wave leveling agent, substrate wetting agent, defoamer, anti-UV additive After pre-mixing with the neutralizer, slowly add to the aqueous hydroxyacrylate dispersion, then add deionized water, continue to stir for 25 minutes, and then add hydrophilic modified siloxane hybrid HDI polyisocyanate and hydrophilic modified IPDI respectively Type polyisocyanate, continue to stir for 2 minutes, then adjust the speed of the mixer to 1100rpm, then slowly add the rheological additive, continue to stir for 5 minutes, let it stand, and filter it with a 400-mesh filter cloth to obtain a water-based polyurethane varnish.

Example 2:

A kind of waterborne polyurethane varnish, its raw material composition is as shown in the following table:

Table 2 A kind of raw material composition table of waterborne polyurethane varnish

The preparation method of above-mentioned waterborne polyurethane varnish comprises the following steps:

Add water-based hydroxyacrylate to the dispersion container, adjust the speed of the mixer to 600rpm, and disperse, and then add co-solvent, long-wave leveling agent, short-wave leveling agent, substrate wetting agent, defoamer, anti-UV additive After pre-mixing with the neutralizer, slowly add to the aqueous hydroxyacrylate dispersion, then add deionized water, continue to stir for 25 minutes, and then add hydrophilic modified siloxane hybrid HDI polyisocyanate and hydrophilic modified IPDI respectively Type polyisocyanate, continue to stir for 2 minutes, then adjust the speed of the mixer to 1100rpm, then slowly add the rheological additive, continue to stir for 5 minutes, let it stand, and filter it with a 400-mesh filter cloth to obtain a water-based polyurethane varnish.

Example 3:

A kind of waterborne polyurethane varnish, its raw material composition is as shown in the following table:

Table 3 A kind of raw material composition table of waterborne polyurethane varnish

The preparation method of above-mentioned waterborne polyurethane varnish comprises the following steps:

Add water-based hydroxyacrylate to the dispersion container, adjust the speed of the mixer to 600rpm, and disperse, and then add co-solvent, long-wave leveling agent, short-wave leveling agent, substrate wetting agent, defoamer, anti-UV additive After pre-mixing with the neutralizer, slowly add to the aqueous hydroxyacrylate dispersion, then add deionized water, continue to stir for 25 minutes, and then add hydrophilic modified siloxane hybrid HDI polyisocyanate and hydrophilic modified IPDI respectively Type polyisocyanate, continue to stir for 2 minutes, then adjust the speed of the mixer to 1100rpm, then slowly add the rheological additive, continue to stir for 5 minutes, let it stand, and filter it with a 400-mesh filter cloth to obtain a water-based polyurethane varnish.

Example 4:

A kind of waterborne polyurethane varnish, its raw material composition is as shown in the following table:

Table 4 A kind of raw material composition table of waterborne polyurethane varnish

The preparation method of above-mentioned waterborne polyurethane varnish comprises the following steps:

Add water-based hydroxyacrylate to the dispersion container, adjust the speed of the mixer to 600rpm, and disperse, and then add co-solvent, long-wave leveling agent, short-wave leveling agent, substrate wetting agent, defoamer, anti-UV additive After pre-mixing with the neutralizer, slowly add to the aqueous hydroxyacrylate dispersion, then add deionized water, continue to stir for 25 minutes, and then add hydrophilic modified siloxane hybrid HDI polyisocyanate and hydrophilic modified IPDI respectively Type polyisocyanate, continue to stir for 2 minutes, then adjust the speed of the mixer to 1100rpm, then slowly add the rheological additive, continue to stir for 5 minutes, let it stand, and filter it with a 400-mesh filter cloth to obtain a water-based polyurethane varnish.

Comparative example 1:

A kind of water-based polyurethane varnish, except that 17% Guanzhi 9025 is replaced by 16% Guanzhi 9018 (equal molar amount of active functional group NCO is replaced), the addition of deionized water is adjusted to 21%, other and embodiment 1 complete Same.

Comparative example 2:

A kind of water-based polyurethane varnish, except that 13% Guanzhi 9018 replaces 15% Guanzhi 9025 (equal molar amount active functional group NCO replaces), the addition of deionized water is adjusted to 21%, other and embodiment 2 complete Same.

Comparative example 3:

A water-based polyurethane varnish, except that Liangu 3597A is not added, and the addition of deionized water is adjusted to 25%, the others are exactly the same as in Example 3.

Comparative example 4:

A water-based polyurethane varnish, except that Liangu 3597A is not added, and the addition of deionized water is adjusted to 25%, the others are exactly the same as in Example 4.

Performance Testing:

1) The viscosity change test results of the water-based polyurethane varnishes of Examples 1-4 and Comparative Examples 1-4 stored at room temperature (25°C ± 2°C) are shown in the table below:

Table 5 Viscosity change test results of waterborne polyurethane varnish stored at room temperature

Note:

Viscosity: Test with reference to "GB/T 1723-1993 Coating Viscosity Measurement Method".

2) The appearance test results of the paint films obtained after the water-based polyurethane varnishes of Examples 1-4 and Comparative Examples 1-4 were parked for different periods of time at room temperature (25°C ± 2°C) are shown in the table below:

Table 6 The appearance test results of the paint film obtained after the water-based polyurethane varnish was parked at room temperature for different times

Note:

Appearance of the paint film: judge with the naked eye according to the actual situation of the paint film.

3) The performance test results of the paint film obtained after the water-based polyurethane varnishes of Examples 1 to 4 and Comparative Examples 1 to 4 were parked for 15 minutes at room temperature (25°C ± 2°C) are shown in the table below:

Table 7 The performance test results of the paint film obtained after the water-based polyurethane varnish was parked at room temperature for 15 minutes

Note:

Pendulum hardness: test with reference to "GB/T 1730-2007 Pendulum damping test for paints and varnishes";

Pencil hardness: test with reference to "GB/T 6739-2006 Paint and Varnish Pencil Method for Determination of Paint Film Hardness";

Gloss: test with reference to "GB/T 1743-1979 (1989) Determination of Paint Film Gloss";

Adhesion: test with reference to "GB/T 9286-2021 Cross-cut test of paint and varnish film";

Water resistance: test with reference to "GB/T 1733-1993 Determination of water resistance of paint film".

4) The pot life and the paint film performance test results at the end of the pot life of the water-based polyurethane varnishes of Examples 1 to 4 and Comparative Examples 1 to 4 at room temperature (25°C ± 2°C) are shown in the table below:

Table 8 Pot life of water-based polyurethane varnish at room temperature and test results of paint film performance at the end of the pot life

Note:

Acid resistance and alkali resistance: test with reference to "GB/T 1763-1979 Determination of Chemical Resistance of Paint Films".

It can be seen from Table 5-8 that:

a) The pot life of the water-based polyurethane varnishes of Examples 1 to 4 is greatly extended, and the formed paint film has high water resistance (especially water boiling resistance), and the paint film has high gloss, high hardness, and excellent chemical resistance. Comprehensive Excellent performance;

B) the water resistance and the boiling resistance of the paint film formed by the water-based polyurethane varnish of comparative example 1 and comparative example 2 are far inferior to the water-based polyurethane varnish of Examples 1～4;

C) the water-based polyurethane varnish of embodiment 1～4 is all excellent in all respects performance during application period;

d) The pot life of the water-based polyurethane varnishes of Example 3 and Example 4 is as long as 5h and 6h, while the water-based polyurethane varnishes of Comparative Example 3 and Comparative Example 4 have produced a large number of pinholes, foaming, etc. in the paint film at 4h Cosmetic defects, no longer applicable;

In summary, the water-based polyurethane varnish of the present invention greatly prolongs the pot life of the varnish and improves the water resistance of the paint film, especially the water boiling resistance, on the premise of excellent appearance and excellent comprehensive performance.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (7)

1. The water-based polyurethane gloss oil is characterized by comprising the following components in percentage by mass:

aqueous hydroxyacrylate dispersion: 45% -55%;

hydrophilic modified siloxane hybrid HDI-type polyisocyanate: 13 to 20 percent;

hydrophilic modified IPDI type polyisocyanate: 4% -8%;

cosolvent: 4% -8%;

long-wave leveling agent: 0.3% -1.0%;

short-wave leveling agent: 0.1 to 0.3 percent;

substrate wetting agent: 0.2 to 0.5 percent;

defoaming agent: 0.1 to 0.4 percent;

anti-UV auxiliary agent: 0.5 to 1.5 percent;

neutralizing agent: 0.05 to 0.2 percent;

rheological aid: 0 to 0.5 percent;

water: 15% -20%;

the hydrophilic modified siloxane hybrid HDI type polyisocyanate is Guanzhi 9025;

the hydrophilic modified IPDI type polyisocyanate is linked-fixed 3597A;

the long-wave leveling agent is at least one of ByK381, pioneer PW336, bright Rabbit LA452, zhanxin XW395, dexin L39, shanghai 3885 and Basff 3772;

the short wave leveling agent is at least one of Digao Tego450, byK333, byK3760, basf 3034 and Dow Corning DC 57.

2. The aqueous polyurethane varnish according to claim 1, wherein: the waterborne hydroxyl acrylate dispersion is at least one of Wanhua 2042, kesi Chuan 2470, zhan Xin 6299W and Guanzhi 4842.

3. The aqueous polyurethane varnish according to claim 1 or 2, wherein: the cosolvent is at least one of dipropylene glycol methyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diethylene glycol monobutyl ether and propylene glycol diacetate.

4. The aqueous polyurethane varnish according to claim 1 or 2, wherein: the substrate wetting agent is at least one of Yingchuang 104E, yingchuang AD01, haro Ke Venadol40, bi Ke BYK346, bi Ke BYK3481, digaTego 270, digaTego 280, digaTego 4100 and DigaTego 4200.

5. The aqueous polyurethane varnish according to claim 1 or 2, wherein: the antifoaming agent is at least one of winning wound MD20, winning wound DF110D and winning wound 118; the anti-UV auxiliary agent is at least one of Pasteur Tinuvin1130, pasteur Tinuvin292 and Pasteur Tinuvin 234; the neutralizing agent is at least one of N, N-dimethylethanolamine and 2-amino-2-methyl-1 propanol; the rheology aid is at least one of a modesty WT105A, BYK425, a Lung PUR62, an Adedic UH752, and a Rouhua U905.

6. The method for preparing the aqueous polyurethane gloss oil of any one of claims 1 to 5, characterized by comprising the steps of: uniformly premixing a cosolvent, a long-wave leveling agent, a short-wave leveling agent, a base material wetting agent, a defoaming agent, an anti-UV (ultraviolet) auxiliary agent and a neutralizing agent, adding the premixed mixture into the aqueous hydroxyl acrylate dispersion, adding water, uniformly stirring, respectively adding hydrophilic modified siloxane hybrid HDI type polyisocyanate and hydrophilic modified IPDI type polyisocyanate, uniformly stirring, adding a rheological auxiliary agent, and uniformly stirring to obtain the aqueous polyurethane gloss oil.

7. The use of the aqueous polyurethane varnish recited in any one of claims 1 to 5 on the surface of a wood ware or carbon fiber composite material.