Water-based all-dumb wood paint development ideas!

Preface:

With the upgrading of people's consumption concept, higher requirements are put forward for the surface coating effect of furniture paint, in the case of the same substrate, half-light thin and transparent, full of dumb skin are the more popular industry words at present, and these coating effects are deeply sought after

Between aesthetics and performance, the waterborne two-component strikes an excellent balance

This article focuses on the matte adjustment of waterborne two-component paints, the effect of maintaining matte, obtaining better transparency, while maintaining the balance of other physical properties, as well as the breadth of construction

1.

1.

Aqueous hydroxypropyl emulsion: DSM-EM1, Monkey Fairy EM2, Currison EM3, Top EM4, Lingu EM5

Water-based curing agent: HDI trimer, modified TDI trimer, modified HDI curing agent

Matting agent: wax powder 2382/2090/2093, matting agent: OK607

Wetting agent: 4100, defoamer: 6028, thickener: 361, 362, rheogeneic agent: 7800, accelerator: K102, DBTL
.

Dispersant: 190
.

1.
2 Experimental equipment:

High Speed Disperser, NDJ Viscometer, DTC100um Wire Rod, W71 Spray Gun, Electronic Scale (Accuracy 0.
01), Oven, Pencil Hardness Tester
.

1.
3 Preparation of coating film

According to the test formula, the samples
are made on the glass plate and the white beech veneer according to the following scheme.

(1) On a 150 mm×200 mm colorless glass plate with a 100 μm wire rod coater to make a film, 50 ° / 24h drying;

(2) Spray two channels on the 70 mm × 70 mm white beech veneer plywood, the first spray amount is 100 g/m², after 50 °/6h, the 400 # sandpaper is gently sanded once and wipes off the floating ash, and the second channel is sprayed according to the spraying amount of 100 g/m², and the
second channel is dried at 50 °/24h.

1.
4 Coating performance test

1.
4.
1 Gloss (60°)

Measure the coating gloss on the glass plate with a gloss meter, measure 3 samples, and take the average
.

1.
4.
2 Hardness

Measure the hardness of the glass plate with a pencil hardness meter, measure 3 times /block, and take the average
.

1.
4.
3 Chemical resistance test

Ethanol resistance, water resistance and acetic acid resistance were tested on white beech veneer plywood
.

1.
4 Result Judging

In tests such as transparency and resistance, when there is no other explanation, 5 indicates the best and 1 indicates the worst
.

2.
Experimental part

2.
1 Emulsion selection experiment

Judging from the test results, under the condition of large thickness of the paint film, the compatibility is better EM2:EM3, EM4:EM5, respectively, the transparency is high
.
The principle of choosing two resins is that the curing rate difference is large, the two resins in the drying process, due to the difference in the rate of drying, in the film formation process, the rapidly dried resin is preferred to form the film, and when the subsequent dry resin is filmed, because part of the paint film is in a semi-dry state, the stress in the paint film rises, resulting in a rise in incompatibility on the microscopic level, and the surface will produce microscopic roughness, thus achieving the purpose of
dumbness.
Follow-up experiments
were performed compared to preferred EM4/EM5.

2.
2 Selection of emulsion ratio

The two emulsions were mixed in different proportions, after the oil adjustment was set at a set time interval, the scraper was carried out to confirm the gloss and transparency, and the experimental results showed that when the EM5 content > 50%, the gloss of the system decreased with the extension of the oil blending time, and the gloss dropped by 10 GU in the 1h time after the oil adjustment, so stable, although the subsequent gloss continued to be stable, but the phenomenon of the decrease in the gloss after the oil adjustment over time could not be used normally in actual production.
Otherwise, the same batch of furniture will have the problem
of inconsistent gloss before and after.
At this point, we have set the ratio of the use of the two emulsions to EM4:EM5=2:1
.

2.
3 Choice of matte agent

The combination of the two emulsions provides the basic properties of the film-forming, while providing the high transparency of the system, which is still not enough to achieve the purpose of full dummy, so the combination
of matte agents is still required in the system.

Since the refractive index of the polymer wax powder is closer to the film forming of 1.
49, the case of the same gloss shows better transparency
than the inorganic matte powder (1.
54).
Thanks to the smooth nature of the wax itself, it is also more prominent
than ordinary matte powder in terms of anti-bright lines.
And wax powder 2093 can provide hardness while providing matte, which is what we want to see
.
Equilibrium chose 2093, which can provide higher hardness, as the matte agent
of the system.

Polymer wax powder are through a special treatment process, in the emulsion or dispersion system has good dispersion performance, in order to avoid due to low emulsion viscosity, wax powder is easy to float on the emulsion after adding, causing some wax powder to clump, so it is necessary to use thickener to thicken the emulsion and then put into the wax powder, in order to achieve the purpose
of rapid dispersion to standard fineness.

2.
4 Selection of curing agent

There are several commonly used curing agents on the market, conventional HDI trimers have good compatibility, high transparency, moderate drying, and special modified HDI provide better matting effect
.
Compared with other physical properties are comparable
.
Of course, due to the decline in gloss, it leads to a decrease
in transparency.
In this resin system, the activation period of the curing agent is relatively stable, and no viscosity is seen to rise too much, thereby ensuring the stability of end use and providing a wider construction window
.

2.
5 Effect of accelerators

As we all know, DBTL in the wood industry, most of the scenarios are banned catalytic additives, and the substitute organic bismuth has a greater impact on the activation period of the system, and does not contribute much
to the practical work of the system.
Different from the above two types of accelerators, K-102 is a completely environmentally friendly functional additive, which has the excellent function of improving water resistance in the one-component system, while in the two-component system, the biggest advantage is not to shorten the activation period, and effectively shorten the drying time
.
As the dosage of K-102 increases, the acupressure drying time is shortened and can be minimized
at 2% of the dosage.

2.
6 Optimize the formula

2.
7 Performance testing

3.
Conclusion

A.
Polymer wax powder provides a matte effect in the system, while assisting in improving the hardness of the system, and the transparency effect on the system is far better than that of ordinary silica products
.

B.
Accelerator K-102 can significantly add the drying rate of the system, which is of great significance for actual production and can effectively improve production efficiency
.

The modified HDI trimer with polymer wax powder effectively reduces the gloss of the system to less than 5GU, and does not affect the chemical resistance of the system, and improves the scratch resistance of the paint film, which is a very big advantage
for the matte system.