Several Common Production Processes of Acrylic Sheets

1. Acrylic sheet production process: casting and molding production method

The casting plate is made of brand-new MMA. Under the action of the initiator, it is heated and polymerized. When the conversion rate reaches 10%, it is cooled to room temperature. After degassing, it is poured into the template made of inorganic glass, and heated in a water bath and drying room. After the material is polymerized, it is formed, and the acrylic sheet is covered with a film and packaged into a finished product.

Acrylic sheet casting production must use molds, and the texture, shape and structure of the processed product surface are very complex, so the production scale is suitable for small batch production. Products made by casting have high toughness and strength, and are also good for viewing. Visually speaking, the casting process is like making tofu. An outer frame mold is injected with soy milk, and then a plate is pressed against it, and it solidifies and becomes tofu. This process can make very thick plates, but the tolerances will be relatively large.

Casting plate is harder than extruded plate, lighter and tougher than glass, and easy to process, engrave, bend silk screen, spray painting, etc. It is widely used, such as acrylic light boxes, signs, bathrooms, display racks, acrylic handicrafts , skylights, buildings, etc. In addition, the sheet after casting needs to be post-treated, and the post-treatment conditions are 2h at 60°C and 2h at 120°C.

2. Acrylic sheet production process: extrusion molding production method

Polymethyl methacrylate can also be extruded, and plexiglass plates, rods, pipes, sheets, etc. can be prepared with the particles produced by suspension polymerization, but the profiles prepared in this way, especially the plates, have small molecular weight. The mechanical properties, heat resistance, and solvent resistance are not as good as casting profiles, especially for pipes and other profiles that are difficult to manufacture by casting molds. Extrusion molding can use a single-stage or two-stage vented extruder, and the screw length-diameter ratio is generally 20-25.

The extrusion plate is formed by mechanical extrusion. The extrusion process is like extruding a dumpling skin between two metal drums. The thickness is relatively uniform, but a thicker plate cannot be extruded. Acrylic sheet extrusion method can realize large-scale, large-scale mass production. The production method of extrusion can be fully automated, and conversely, this advantage also makes processing inflexible, and the process flow and product model cannot be easily changed.

3. Acrylic sheet production process: injection molding production method

Acrylic sheet injection molding uses pellets obtained by suspension polymerization, and the molding is carried out on a common plunger or screw injection molding machine. Typical process conditions of injection molding: injection molding products also need post-treatment to eliminate internal stress. The treatment is carried out in a hot air circulating drying oven at 70°C-80°C. The processing time depends on the thickness of the product, and generally takes about 4 hours.