A new generation of liquid polymers for solvent-based coatings

Back in the entire coating history, most coatings are solvent-based, but they are under enormous pressure as more and more attention is paid to reducing volatile organic compounds (VOCs). Reducing VOCs while maintaining critical application properties, such as viscosity, has become increasingly important if solvent-based coating performance is still required in applications.
challenge for today's coating formulator is to minimize solvent use while developing a flawless and acceptable coating
at the lowest
. A common method is to increase the solid content of the coating, but the result is usually an increase in the viscosity of the product, which in turn causes difficulties in the coating during the construction process.
although other polymer coatings are becoming more and more common, alicylic resin finishes remain one of the highest-selling coatings in the world. Aliclicic resin systems are successful because they are relatively inspensive, versatile and familiar to end users. They can be selected and proportioned by raw materials and/or modifiers to meet the requirements of different end users. Manufacturers have been developing new and improved systems to accommodate high-solid-containing formulations to meet increasingly severe air pollution regulations.
can also be used in a variety of alternative ways to adjust the coating formulation to reduce viscosity, thereby reducing the required solvent, so that the coating to the required construction viscosity range. Liquid polybutylene (LPBDs) is a highly active liquid hydrocarbon polymer that can be used in solvent-free or low-solvent coating formulations. These polymers are similar in many ways to natural dry oils, but due to their high level of unsaturatedness, certain specifications cure faster than many natural oily polymers, and can be accelerated by adding metal drying agents. Liquid polybutylene coatings are generally lighter, harder and more resistant to chemical corrosion than natural oils. They have proven to be particularly suitable for use in primers, with excellent adhesion and corrosion resistance on steel.
, further research has been carried out on the potential properties of liquid polybutylene in solvent-based coatings. In this study, we looked at the benefits of newly developed liquid polybutylene (LPBd-B) compared to other commercially available liquid polybutylene in solvent-based aolate coatings. Compared with the industrial product LBD-A, the new liquid polybutylene (LPBd-B) has a lower molecular weight and a higher 1,2-vinyl content.
results show that the next generation of liquid polymerized butylene (LPBd-B) is more compatible in aolic acid resin systems, giving greater potential for formulation adjustment and even closer to solvent-free systems. Our research also shows that it is possible to improve coating performance while reducing the viscosity of the coating.
The compatibleity of liquid polybutylene polymers with alcoholic acid resins
currently, three commonly used long-oil alcoholate resins have been evaluated: one is a 100% solid content flax oil-based alcoholic acid resin, and the other is a 70% solid content dissolved in petroleum solvents (one is flax oil base, one is soybean oil-based) anoric resin. Mixes prepared at a specific scale are dispersed on a high-speed dispersion machine at 2000 m/min for 5 minutes and then transferred to a glass container to assess storage stability. One batch was observed at room temperature and the other sample was placed in an oven at 40 degrees C for 24 hours. The compatibness of liquid polybutylene in the alicyl resin system was evaluated, and visual observation was carried out after 24 hours and 7 days. Experiments show that the three aliclicic acid resins and the two LBD products have good compatible.
the next main focus on solvent-based aolate resin 1 (100% solid content of long-oil flax oil base) research, and its compatible with different liquid polybutylene in-depth discussion. Based on the test results of the screening method, the maximum amount of liquid polybutylene can be added in aolic acid resin 1 can be determined. At the same time, the specific evaluation method is to brush each mixture on aluminum foil to highlight any potential paint film defects.
results show that the new generation of liquid polybutylene (LPBd-B) is better than LBD-A and has better compatible in alicic acid resin 1. The next generation of liquid polybutylene (LPBd-B) adds more to the resin without the appearance of the coating (Figure 1). In addition, there are no defects in the wet film or dry film when the brush is applied to the aluminum foil for testing.
the fluidity characteristics of the mixture was measured on the fluid meter (Figure 2). The viscosity of alicic acid resin 1 decreases with the increase of temperature. A similar phenomenon occurs when liquid polybutylene (LPBd-A) is added, next-generation liquid polybutylene (LPBd-B) or solvent (i.e., petroleum solvent). Experiments show that mixtures containing 20 solvents have the best dilution effect on alicic acid resins.
application performance in transparent systems
the aliclicic acid resin 1 is made into a transparent coating to evaluate the application performance of the coating; We assess drying time, fluidity and hardness, respectively. Through test evaluation, the penetration performance of transparent varnish on substrates is collected, as well as further research on the 100% solid content, lower VOC content system information.
drying
the table below contains a series of formulations to assess the effect of liquid polybutylene on drying time (Table 1). Aliclic acid resin 1 is partially replaced by LBD A or LPGD-B. At room temperature, adjust by adding a thinner to achieve the same viscosity.
each formulation coating is coated with a 75um wet film on the glass plate. The drying time is assessed simultaneously with a linear drying time recorder. The opening and full curing times of the paint film are determined by visual evaluation and scratches on the dry film surface (Table 2).
the addition of LBd-B slightly extended the opening hours, while LBd-A had no significant effect compared to the comparison of alcohol-containing resin 1.
, the low-added formula of LBd-A or LPGd-B actually has a slightly higher dry time than the contrasting formula. The LBd-B formula with high additions is significantly different, but the dry time is shorter.
hardness
be evaluated through a series of formulations that replace part aliclicate resins and partial thinners with LBds. The viscosity has not been adjusted to emphasize the potential benefits of LPGd.
the hardness of the coating was determined by pencil hardness. Apply 100um wet film (WFT) to the glass plate with a lacquer film preparer. The paint film is tested after 7 and 14 days of maintenance (Table 3).
addition of LBd-A to the transparent coating does not improve the hardness of the pencil. Compared with the comparison sample (no other additives in aolic acid resin 1), the hardness of the experimental sample coating is similar or lower. However, the addition of a low LBd-B to the alicyl resin 1 increases the hardness of the coated pencil. However, after the addition continues to increase, there is no significant increase in hardness. We found that the higher the addition of liquid polybutylene, the slighter the pencil hardness of the transparent coating.
of the coating substrate
the permeability of the coating is evaluated by selecting the oak substrate. A series of confumxes were tested to highlight the potential benefits of liquid polybutylene.
each mixture is transferred to a glass container. The oak plank is first soaked in a paint solution for 15 minutes, then removed and removed from excess paint. Each oak plank is maintained at room temperature for a period of time before intercepting the cross-section from 1.5 cm or 3.5 cm from the bottom of the plate. The model is polished, each cross-section is then examined with a digital microscope, and the surface and telomere migration of the model are evaluated (Figure 3).
the results of the cross-sectional digital microscope at a depth of 1.5 cm, it is found that in the contrasting mix, it is mainly the penetration of the substrate surface. Adding 5 parts of LBd-A to a transparent coating allows the coating to cover the entire plank and the complete telomere migration can be clearly observed. There is some evidence that telomere migration improved further by adding five LBd-Bs compared to the comparison. To achieve full coverage, LPGd-B needs to be increased to 20 copies.
cross-sectional analysis is carried out at a depth of 3.5 cm in order to study the penetration of mixed coatings in wood in greater depth. In the model of the contrast sample, penetration and some telomere migrations were observed over a certain area. When LBd-A was added in 5 parts, the permeability of the substrate and the mixing contrast sample were essentially the same, but no telomere migration was observed. Although LPBd-B reduces the permeability of wood when adding 5 servings, its telomere migration is similar to that of the comparison sample. The results show that telomeres migrate along the model. However, when the addition was 20 servings, LPBd-B was more permeable and telomere migration was more pronounced than the comparison sample (Figure 4).
one way to reduce VOC in solvent-based coatings is to increase the solid content, a series of formulations have been developed to replace thinners with LBd-A, LPBd-B or alicylic resin 1. As a result, coating formulations are shifting towards higher solid content and allow for the evaluation of 100% solid content systems.
metal dryers and anti-cortides are adjusted and calculated based on the total resin weight %w/w. Each formula uses a coater to make wet films of 50 m and 100 m thickness on the glass plate. Then the paint film was placed at room temperature and dried for 24 hours to observe the experimental results.
in order to compare different systems and evaluate the contrast formula with a solid content of 65%, the formula has good film-forming properties on the glass (50 m and 100 m wet film thickness). The total solid content can be increased by adding aolic acid resin1, and the paint film has a good film-forming characteristics at 50 m (lower wet film thickness), but the wrinkle defect of the paint film is observed at 100 m thickness. The wrinkle effect is most likely due to the paint film table drying too fast. Adjusting the content of the metal drying agent in the formulation should eliminate this coating defect. LBd-A can increase the total solid content of transparent coating system, but in both thicknesses there will be paint film defects. The results confirm the earliest compatibility findings that LBd-A cannot be evenly mixed at high additions. However, by introducing LPGd-B not only to obtain a higher system solid content, but also in both thicknesses (50 m and 100 m) the paint film is clear, transparent, no appearance defects, we can clearly notice the benefits.
addition, the increase in solid content affects the viscosity of the transparent system, and reference formulations V15 (LPBd-A) and V17 (LPBd-B) can confirm the dilution effect of liquid polybutylene. The increase in the viscosity of formulations containing aolic acid resin 1 (formula V21) is even more significant, which can lead to application performance problems due to high viscosity.
in order to determine the VOC content in those formulations, GC-MS analysis is performed according to internal testing methods. The results and chromatography of GC-MS analysis clearly showed a decrease in VOC content in formulations with higher solid content. The use of LPGd instead of diluent in aolic acid resin 1 significantly reduced the VOC content in the formulation. In formulations V15, V17 and V21 (Figure 5), there are some differences in the system in which resins are added to replace solvent content.
, as expected, the total amount of VOC is reduced by adding polymer resins to increase the solid content of the system. In the formula tested, thinners are clearly the main source of VOC.
conclusions and further work
This study confirms the advantages of the application of liquid polybutylene polymers in solvent-based coatings, as well as the additional (performance) enhancements obtained from the new liquid polybutylene. The results show that the addition of liquid polybutylene can increase the solid content of solvent-based alcoholic acid coating, thereby reducing its VOC content. The addition of this 100% solid liquid polymer means that the target of 100% coating solid content can be further approached. In addition, data show that the addition of new liquid polybutylene improves the permeability of coatings to wood, especially telomere penetration. We also note other advantages, such as longer opening times and faster do-it potential in transparent coating systems. By optimizing the addition of liquid polybutylene, the hardness of the paint film can also be improved.
the use of newly developed liquid polybutylene enhances the application performance of coatings without adversely affecting other key properties, such as gloss, color or outdoor exposure.
We have demonstrated the advantages of newly developed liquid polybutylene products in solvent-based coatings for a specific resin system, and plans to further study its application in other resin systems and evaluate their performance on different key substrates, including oily metals and surface unprocessed.
。