What are the preparation methods of luminous plastics?

The preparation of luminous plastics usually varies according to the addition method of luminous agent and the production process of plastic products or materials.
The main methods are direct addition, masterbatch addition and in-situ polymerization addition.
① Direct Addition Method Direct addition method is the simplest method. The plastic luminous agent powder is directly mixed with the resin. In order to mix and disperse evenly, it is best to mix with the powdered resin. For example, when the resin is polypropylene (PP), it is better to choose powdered polypropylene, and a dispersant, such as liquid paraffin and mineral oil, is added during mixing. If the noctilucent polycarbonate (PC) plastic is prepared by direct addition method, the technological process is as follows: the PC is baked at 120℃ for 3-10h, and the noctilucent powder is baked at 80℃ for 3-10h. Weigh PC, dispersant and other components according to the mass ratio, and put PC and dispersant into a mixer to mix evenly. Weigh the remaining materials and put them into the mixer to mix for 3 ~ 5 minutes until the plastic luminous agent is uniformly attached to the surface of PC particles. The mixed raw materials are put into the hopper of a twin-screw extruder, and are extruded and granulated by melting.
The extrusion process is as follows: the temperature of zone 1~4 of twin-screw extruder is 230~250℃, the head temperature is 235~245℃, the residence time is 1~2min, and the extrusion pressure is 12~16MPa.
② Masterbatch Addition Method In order to disperse the plastic luminous agent in the resin more evenly, firstly, the luminous agent was dispersed in a certain polymer with high concentration, and then the masterbatch was dispersed in the plastic. This addition method can not only improve the dispersion degree of plastic luminous agent, but also reduce the friction between plastic luminous agent and machinery during processing, and reduce the degree of performance deterioration of plastic luminous agent caused by processing. If the luminous masterbatch is used to prepare polypropylene luminous plastics, the technological process is as follows: SBS naphthenic oil and plastic luminous agent are weighed according to the formula ratio, mixed in a high-speed kneader, and then the materials are taken out and granulated by a twin-screw extruder, so as to obtain SBS luminous masterbatch, and the content of plastic luminous agent in the masterbatch can reach 80%. Then, the luminous master batch of styrene-butadiene-styrene copolymer (SBS) was mixed with PP according to a certain proportion, and the mass fraction of plastic luminous agent was about 10%, and then the luminous PP material was obtained by extrusion granulation. Luminous PP can be processed into plastic products by extrusion or injection molding. SBS luminous masterbatch can also be mixed with PP in a certain proportion and directly extruded or injection molded to produce luminous plastic products, but luminous
The dispersibility of the agent is poor.
③ In-situ polymerization addition method The in-situ polymerization addition method of plastic luminous agent is to add luminous agent during polymer synthesis, at which time the plastic luminous agent can be chemically bonded with plastic polymer. Practice has proved that the luminous performance of plastics is generally not affected by adding luminous agent by this method, but the physical and mechanical properties of plastics are improved, which also simplifies the subsequent processing technology
The dispersion and mixing process of plastic luminous agent before processing is omitted. This method can be mainly used for plastics such as nylon plastics, polymethyl methacrylate (PMMA), etc., which are molded by casting their monomers.
If the luminous nylon 6 plastic is prepared by in-situ polymerization, the technological process is as follows: firstly, 95% of caprolactam, 2% of aminocaproic acid and 3% of water are added into the reactor, and placed in a constant-temperature oil bath tank under the protection of N. After the monomer is melted, the temperature is gradually raised, and when the temperature reaches 140℃, stirring is started, and the plastic luminous agent is added at 255℃ for 4-5h to obtain a viscous nylon 6 molten product, and the reaction is carried out.