Sports ground has its particularity, first of all, as a direct contact with the interface with the athletes, the athletes make the trip, running, jumping and other action, without prejudice to the premise of its operation, requires the greatest degree of assurance of their safety; secondly, As a professional workplace, sports ground movement must be able to provide good performance. To ensure that these two points, the application of sports ground coating is necessary. In addition, as the increasing commercialization of sports industry, has a good viewing of the sports venue is a must, sports ground coatings can better provide this function, and its bright luster, full of inside information to improve the live broadcast and view the results. Sports ground coatings are increasingly concerned about movement building materials industry.
First, an overview of the development of sports ground coatings
Most of the sports ground for the wooden floor, so many of the sports floor coating products are developed for sports flooring. As the traditional decorative wooden floor exercise care is coated on its surface paint, paint it with high content of volatile solvents can not meet the requirements of the people and the environment. In this case, water-based acrylic emulsion paints and water-based polyurethane coatings have been developed one after another. Nontoxic acrylic latex paint with water as solvent, the environment has improved. Such copolymers have better thermal stability, photochemical stability and oxidation resistance. Film as a wood flooring material, has good gloss, film-forming properties and adhesion properties. However, acrylic acid (ester) emulsion such as relatively poor scratch resistance, low temperature brittle, sticky and so hot. Especially as playground flooring, the coating wear resistance, scratch resistance requirement is very high. Ordinary acrylic acid (ester) emulsion where such use can not be qualified. Polyurethane coating addition to acrylic acid (ester) emulsion advantages but also has the advantages of good wear resistance, but it is very expensive, is generally paint a dozen or even twenty times, and the tolerance and anti-black offset poor performance. Currently on the market, better performance products are mainly three types of silicone modified acrylic emulsion, polyurethane and acrylic emulsion and heavy complex two-component emulsion.
1. Silicone modified acrylic emulsion
Organosilicon compounds with low surface free energy [1], and when and acrylic acid (ester) copolymer as silicone, the coating can form a stable siloxane film, it has good water-repellent coating, anti- dirt and wear resistance. In addition, the performance as one of the important sport coat, non-slip safety for the sport has a very important role. Excessive static friction coefficient is too small may result in sports injuries of athletes. For these points of the synthesized silicone modified acrylic emulsion coating as the movement's core wood floor care materials, improve the water resistance of the coating, solvent resistance, abrasion resistance, scratch resistance and weathering; and Modification of nanoparticles coated with surface structure, effectively control the performance of the coating slip is gradually becoming a sports ground coatings market, brand-name products.
2. Polyurethane and acrylic compound latex emulsion and heavy two-component
Polyurethane and acrylic latex compound the advantages of integrated polyurethane and acrylic, the use of complex technical and scientific formula, weaknesses, especially in the coating wear resistance is greatly improved, but the water resistance and stain resistance there is a lack of . Heavy two-component emulsion is mainly used in heavy situations and to withstand vigorous exercise venue, with excellent wear resistance, emulsion containing polyurethane, product components are added to the second curing, reducing the film formation time.
Second, synthetic sports surface coatings Research technology
Silicone modified acrylic emulsion technology is a synthesis of current research focus. Silicone modified acrylic emulsion by seed emulsion polymerization method [2], with a reactive silicone monomers and acrylic emulsion copolymerization to obtain core-shell structure with a silicon modified acrylic emulsion . Emulsion polymer particles containing Si-OH active groups, film curing, the catalyst, the polymer chain Si-OH condensation between active groups, cross-linked to generate Si-O-Si bond . While the polymer chain Si-OH active groups and also hydroxyl substrate surface (such as the wooden floor-OH hydroxyl groups on cellulose) intermolecular dehydration to form stable cross-linked siloxane membrane (see Figure 1). Therefore, the cured coating can significantly improve the wear resistance, hardness and adhesion properties. And the Si-O covalent bond energy of its relatively large, about 432kJ/mol, have a good heat, light stability and weather resistance. In addition, the siloxane network structure of the surface free energy lower hydrophobic good, so that after curing the coating in water, stain and scrub resistance, better sexual performance.
According to the author of the study, the polymer emulsion particle size is an important parameter, its application of core-shell polymer emulsion has a great influence. Nano-particle size to ensure that the polymer latex in the film, the polymer microspheres amalgamation between the good. When the polymer emulsion as the film that has good film forming properties, flow properties and good gloss levels. The distribution of silicone in the shell sample size analysis and TEM images shown in Figure 2, the results show that the average size of polymer latex 99.5nm, and the polymer particles showing a special sphere toothed edges.
Third, the sports ground safety coating
Non-slip coating, friction coefficient is not the bigger the better, when the friction coefficient is too large, the ground will be very astringent, athletes will lead to difficulties due to an ankle injury sliding; when the friction coefficient is too small, unable to control their players on the ground sliding, easy to slip and hurt the knee [3]. Therefore, static friction coefficient of the coating should be in the appropriate context, the provisions in the ASTM standards for sports flooring in the static coefficient of friction coating more than 0.5 [4,5]. Of years of research found that the deployment of products in the amount of polyethylene wax dispersion can be carried out within a certain range of static friction coefficient of the deployment. Figure 3 for the coating of the membrane surface structure, is the tiny particles of polyethylene wax dispersion. Since relatively small molecular weight polyethylene, film occurs when the "drift" and more concentrated in the coating, this coating to control the surface structure of the surface of the static coefficient of friction have a very active role, through the deployment of the product wax the amount of dispersion coating can be flexibly control the static friction coefficient. When the wax content of the product were 0% and 5%, with the ASTM (James Machine) method of measuring substrate in PVC film coating measured static friction coefficients were 0.47 and 0.58. Both skid resistance and other properties desirable coating wax content of the preparation of the appropriate coating, the static coefficient of friction standard. The same determination with DIN18032, the development of sports flooring products in the determination of the sliding friction coefficient matrix shown in Table 1, are required in the standard 0.4 to 0.6 range.
Fourth, sports ground coatings characterization
The emulsion as the core material, adding wetting agent, stabilizer, film-forming agent, leveling agent, plasticizer, polyethylene wax emulsions, defoamers and other re-dubbed the beautiful wood floor coating film movement, from Shanghai Paint Performance Testing Institute, the results in Table 2.
1. Luster and durability
2. Tolerance performance
V. Application Example
Application of the coating can not only protect athletes, to extend the role of terrestrial life, plus a very good decorative effect. Usually applied after the coating has good slip properties of the ground, feet feeling soft (do not paint a rigid sense), not easy to produce exercise-induced fatigue and injury, good visual sense (not very strong or the glare of the reflection effect, not cause visual fatigue of athletes), and good television effect. Figure 4 shows the beautiful wood floor coating film movement in some professional sports competition and training venues in the application of results.
