A new idea to develop indoor 70/30 system matting agent

A new idea to develop indoor 70/30 system matting agent

Deng Jian Cui Kebin

(Wuhan Yincai Technology Co., LTD.)

Abstract: The 70/30 epoxy system, characterized by low epoxy content and high polyester catalyst levels, has long presented challenges in achieving effective Matting. Despite years of research efforts, significant breakthroughs remained elusive. Our team adopted an innovative approach by curing outdoor-grade pure polyester with epoxy in a 70/30 ratio, specifically developing the novel matting agent L2037. Comprehensive evaluations were conducted on this indoor-grade matting agent, including dosage optimization, storage stability, polyester compatibility, and other performance metrics. The results demonstrate that for most polyester materials, L2037 achieves an ultra-low gloss level of 10% (60 ° m/m) while maintaining exceptional stability and performance.

I. Introduction

At present, indoor matting agents are mainly divided into physical matting and chemical matting

The physical matting includes:

① Wax-based matting agents, representing the most traditional and widely-used physical method, operate through an immiscibility mechanism. During melt extrusion, these wax components achieve poor compatibility with resin systems, being dispersed as fine particles within powder formulations. As the resin cures, the wax forms a micro-rough film on the surface, achieving matting effects through diffuse reflection of incident light.

The disadvantage is that the Matting ability is limited, it is difficult to achieve a very low gloss, and may affect the inter-layer adhesion.

② Dry-mixing matting, a simple yet widely adopted physical method, requires no pre-application. The process involves physically mixing two powders with distinct reactivity levels in precise proportions. During curing, the differing viscosities, surface tensions, and curing rates between the powders create microscopic irregularities during melt flow. These micro-structures scatter light, achieving the desired matting effect through light diffusion.

The disadvantage is that two or more powder products need to be stored, and the coating may be separated due to the difference of charge and density of the two powders during the spraying process, resulting in uneven gloss or "ghost" of the coating.

Among them, chemical matting includes:

Acrylic matting agents represent one of the most prevalent and effective methods in modern indoor surface treatment. Operating through chemical incompatibility and competitive reaction mechanisms, these agents partially react with epoxy groups while producing compounds that remain incompatible with the base resin. This inter-facial interaction ultimately creates a micro-surfaced texture with controlled roughness characteristics.

The disadvantage is that the polyester may be selective.

The 50/50 and 60/40 indoor systems for achieving matte finish have been well-established and scaled up in China. However, the 70/30 indoor system still lacks effective domestic solutions both domestically and internationally, with achieving semi-matting remaining challenging. To address this issue, this paper introduces L2037-a novel 70/30-specific matting agent designed to fill the technical gap in this system.

Traditional indoor matting agents are typically formulated for indoor polyester epoxy systems. L2037 innovatively utilizes outdoor-grade polyester instead of the conventional 70/30 indoor polyester blend, delivering superior matting performance. The cost-effective nature of outdoor polyester not only reduces operational expenses but also ensures better storage stability in the final powder formulation due to its high glass-transition temperature (Tg) and excellent storage characteristics.

II. THE EXPERIMENTAL PART

2.1 matting agent L2037 different dosage test

Experimental data shows that L2037 is aimed at the matting of 10-20% gloss range, and the amount is controlled at 3%-5% in powder formulation.

2.2 L2037 test of different polyesters with matting agent

Experimental data shows that 70/30 matting agent L2037 has wide applicability to polyester and excellent absorbance effect. At 5% dosage, the gloss of polyester from different manufacturers is generally about 10%.

2.3 Storage stability test of L2037 matting agent

The experimental data shows that after 8 days of placement under 50℃ conditions, the powder made of L2037 matting agent has no obvious deterioration on the printing surface, the gloss improvement is also within a reasonable range, and it has excellent storage stability.

2.4 Mechanical properties test of L2037 matting agent

2.4.1 Adhesion test

                            Reference standard GB/T 1720-2020

2.4.2 Impact and cup-pull tests

Impact reference standard GB/T20624.2-2006

Cup reference standard GB/T 9753

The test results showed that the mechanical properties of the matting agent L2037 were pass

III. CONCLUSIONS

Wuhan Yincai L2037 is a new type of matting agent developed for the current 70/30 system. It is also the only matting agent available on the market that can be the matting agent in the 70/30 system. It has a series of advantages such as fine finishes, good Matting effect, excellent storage stability and low use cost.

Of course, the matting agent L2037 also has some shortcomings. The pursuit of better mechanical properties and stronger storage stability is also our direction of improvement.