Polymer Acid coatings mainly include thermoplastic acrylic coatings, thermosetting acrylic coatings, high solid acrylic coatings, acrylic latex paints, and water-dilutable acrylic resin coatings.
(1) The main component of thermoplastic acrylic coating is polymethyl methacrylate, but pure polymethyl methacrylate is too brittle, and has poor adhesion to the substrate, and the solvent is not easy to use up, because its glass transition temperature high. The solid content of solvent-based thermoplastic Polymer Acid coatings is too low (volume concentration is about 12%), and the amount dropped sharply after entering the 1970s. Instead, thermosetting acrylic coatings were developed, especially high-solid acrylic acid. coating.
(2) Thermosetting acrylic resin can increase the non-volatile content of the coating, and crosslinking occurs during the curing process after the coating is applied. In addition to higher solid content, thermosetting acrylic coatings have better gloss and appearance, better chemical resistance, solvent resistance, alkali resistance, heat resistance, etc. The disadvantage is that they cannot be stored for a long time. Thermosetting acrylic coatings use melamine-formaldehyde resins or polyisocyanates as crosslinking agents.
(3) It is difficult to prepare Polymer Acid resins for high solids coatings. Generally, the volume solid content of high-solid polyester coatings can reach 65% to 70%. It is easy for polyester to ensure that there are more than two hydroxyl groups on each molecule, but it is difficult for acrylic resin to achieve more than two hydroxyl groups on each molecule. hydroxyl. In order to solve this problem, one is to increase the amount of hydroxyethyl methacrylate (HEMA), such as increasing it to 15%; the other is to make the molecular weight distribution of the resin as narrow as possible, and the distribution of polar groups should be as uniform as possible. The latter is very critical in high solids coatings. At present, the volume solid content of high solid acrylic resin coatings can reach 54% to 56% (weight solid content can reach 70% to 72%) under the spray viscosity.
(4) Acrylate latex is the best and most important latex. Compared with polyvinyl acetate emulsions, Polymer Acid emulsions improve the flexibility and adhesion of coatings, and the cost is moderate. In addition, its outdoor durability, including resistance to UV light degradation, is significantly improved, leading to applications in architectural coatings for walls, floor polishes that can be scrubbed and decontaminated, and paint printing pastes.
(5) Water-dilution Polymer Acid resin is a thermosetting resin. First, a water-soluble polymer is prepared, which will be cross-linked into a water-resistant and tough coating during film formation. Water-thinned acrylic paints can be used for spray painting, dip painting, etc. The most successful application is can lining coatings. Another important application is electrophoretic paint.