Application of dual-base group structure anti-sink dispersant DAD in matte coatings

0 forewordIn the production of matte coating due to the use of dumb powder, its anti-sinking, uniform arrangement has become a key factor affecting the quality of product storage and coating, the use of traditional dumb powder anti-sinking agent, whether in storage or thinning construction process, the total appearance of layering (i.e., dumb powder subsiding), dumb powder easy to roll and other phenomena become a key factor affecting the quality of coating. Developed by the Institute, this dual-base group structural anti-sink dispersant (D o u u b l e b a s e a t i -settling Dispersability, DAD) is designed to improve the current problems in matte coating storage and coating, based on the latest coating additive technology anchoring and bonding, in an attempt to provide more options for the production of matte coatings. Experiments show that D A D anti-sink dispersant can effectively solve the phenomenon of matte coating layering, dumb powder rolling, and so on, so as to obtain better coating quality.1 test1.1 main rawaolate resin (grade), industrial grade, self-produced; D A D anti-sink dispersant, industrial grade, Shundnama Chemical Co., Ltd.; Desiccant B Y K -141, Chemical Purity, Bicker, Germany; Leveling agent B Y K -306, Chemical Pure, Bicker, Germany; E D -2 dumb powder, industrial grade, Guangzhou Grace Company; I L1451, L-75 curing agent, industrial grade, Bayer, Germany; Mixed solvent, industrial grade, self-matching.1.2 Preparation of matte coatings 1.2.1 Basic formulation of matte coatings (see Table 1) 1.2.2 preparation process for matte coatings μ≤ Add other residual additives and an appropriate amount of mixed solvent to the finished paint, adjust the viscosity to 60 to 80 s (coated with 4 s cups) to filter out the material. The paint ingredients and curing agents are made of matte coating according to the ratio of 2:1 (quality ratio).1.3 performance testtest tank debling, dilution and anti-sinking, according to the national standard G B / T6753.3-86 test storage stability, and according to the national standard G B / T1727-1992 requirements sprayed on the test board, according to the national standard G B / T1748-79 test coating gloss, according to the national standard test coating gloss, according to the national standard test other mechanical properties.2 Results and discussion of the effect of 2.1 DAD on the storage stability of matte coatingsUnder the condition of controlling the rotational viscosity of matte coatings of 1,000 m P a s, the effect of D A D anti-sink dispersants with traditional anti-sinking agents (wax slurry) and dispersants on the stability of matte coating storage was examined, as shown in Figure 1.From Figure 1, it can be seen that the use of D A D anti-sink dispersant to prepare matte coating, its storage stability is good, storage 1 a after its degree of subsidion, skin, viscosity changes are in a very slight change, liquid solid separation layer height is only 0.8 c m, according to the national standard to judge storage stability up to 8 levels. And the use of wax pulp and dispersants as a matte coating anti-sink dispersion, liquid solid phase has a clear layering phenomenon, and with the extension of time liquid solid phase layering phenomenon is also more serious, storage 1 a after the liquid solid separation layer height of 6.0 c m, its storage stability is only 4 levels.the use of wax paste and dispersants to prepare matte coating, the mechanism is that wax pulp through hydrogen bonding to form a certain gel mesh structure and increase the consistency of the coating, thereby delaying the subsidence of dumb powder, while the wax pulp is a dissolved but not dissolved solid Particles, their own has a certain proportion, so in the matte coating storage and construction of the wax pulp itself subsides and causes the dumb powder to sink together, the dispersant is mainly a polymer structure, through the spatial resistance effect to give the dumb powder a certain charge, slow down the dumb powder rolling. The D A D anti-sink dispersant has a unique dual-base group structure, its structure is A-R-B, the molecular end is anchored base A and dumb powder formation structure attraction, firmly fixed on the surface of dumb powder, thus playing a fixed, stable, dispersed dumb powder role; And the other end of the joint base B through and resin hydroxyl, nirch base, etc. to form a certain connective structure, as well as long-chain space bit resistance to anchor the dumb powder stable, even distribution in the coating system, thus achieving to prevent the occurrence of dumb powder subsidon, reunion and other undesirable phenomena. Therefore, compared with the traditional anti-sinking agent (wax slurry) and dispersant coordination system, it has a better storage stability performance, 1 a storage stability performance can reach 8 levels.
2.2 DAD has an impact on the dilution stability of matte coatingsAfter diluting the matte coating and controlling its application with a viscosity of 12 s, the effect of D A D anti-sink dispersant with traditional anti-sinking agent (wax paste) and dispersant on the stable storage performance of matte coating after dilution was examined, and the results are shown in Figure 2.From Figure 2, it can be found that in the construction process of matte coating, due to the very low viscosity, the use of wax paste and dispersant as matte coating anti-sinking, directional system, dumb powder subsidion, layering is particularly obvious, 6 h after the liquid solid separation layer reached 5.5 c m, and the use of D A D system dumb powder only slight subsidion, layering, 6 h liquid solid separation layer is only 0.6 c m. When thinning, due to low viscosity, dumb powder subsides faster, so in the use of wax slurry matte coating to often stir to maintain a relatively equal system. In the system using D A D, because D A D's unique dual-base group structure and resin substitut has a good mixing, it is anchored at one end of the fixed dumb powder, the other end through the active function group and resin can form a bonding, forming a larger form of large molecule overall structure, so that the dumb powder in the matte coating distribution more uniform, and this form of structure by the paint viscosity is small, so it is not easy to settle in the process of thinning.2.3 EFFECT of DAD on matte coating gloss Under the condition that the amount of matte powder was added to 5%, the effect of different dispersants on matte coating gloss was examined, and the results were shown in Table 2.As can be known from Table 2, the formula for adding D A D anti-sink dispersants does not exceed 2 degrees between the different measuring points of gloss on the large plate surface, while the gloss difference between adding a wax slurry and a dispersant is more than 4 degrees. The above reasons for are mainly due to the anchoring base of D A D has a specific adsorption effect on dumb powder, and the active group in D A D can form a joint relationship with the resin, this structure can make the dumb powder fixed, thereby greatly slowing the dud powder reunion, rolling, so that the matte coating gloss made more uniform. 2.4 EFFECT of DAD on matte coating viscosity Different anti-sink agents have a greater impact on the viscosity of the coating due to their different role in the coating, and the test compares the effects of wax pulp and D A D on the viscosity of the coating, as shown in Figure 3. As can be known from Figure 3, because the wax paste in the matte coating through the hydrogen bond action to form a certain mesh structure and increase the consistency of the coating, thereby delaying the subsidion of the dumb powder, so with the increase in dosage, viscosity growth is also faster, and D A D is mainly through the active function group of other components of the paint anchoring to achieve anti-sinking, directional effect, its dosage on the paint's viscosity is not much, so D A D is more suitable for the production of environmentally friendly coatings. 2.5 Compared to the performance of matte coatings made from different anti-sink dispersants D A D, the main properties of matte coatings compared to the formulation of wax paste are shown in Table 3. As can be found in Table 3, the combined performance of the formula for adding D A D is much better than that for adding wax pulp. 3 Conclusion The use of D A D anti-sink dispersant to prepare matte coatings for good storage stability, room temperature 1 a storage, stability performance of up to 8 levels, dilution of 6 h within only a slight subsidence. The increased amount of D A D anti-sink dispersant has a small effect on the viscosity of matte coatings, and is suitable for the preparation of high-solid coatings, resulting in a uniform and stable matte coating gloss, with a surface gloss difference of no more than 2 degrees.