What are the requirements for masterbatch production? This is a big doubt for many friends who have just been engaged in or want to engage in the masterbatch production industry.
To explain this problem, let's start with the requirements of the pigments for the masterbatch. 1. The requirements for the pigments for the masterbatch. The pigments used in the masterbatch must pay attention to the difference between the pigment and the plastic raw materials and additives. The key points of the collocation relationship are as follows.
(1) The pigment cannot react with resin and various additives, and has strong solvent resistance, low migration and good heat resistance. In other words, the masterbatch cannot participate in various chemical reactions. For example, carbon black can control the curing reaction of polyester plastic, so carbon black material cannot be added to polyester. Due to the high molding processing temperature of plastic products, the pigment should not decompose and change color under the conditions of molding heating temperature. Generally, inorganic pigments have better heat resistance, while organic pigments and dyes have poor heat resistance. This point should be paid attention to when choosing pigments. Click on the lower left corner to read the original text and purchase EC5011A breathable rubber particles with one click!
(2) The dispersibility and tinting strength of the pigment should be good. When the pigment is unevenly dispersed, it will affect the appearance of the product; when the coloring power of the pigment is poor, the amount of the pigment will increase and the material cost will increase. The same colorant has different dispersibility and tinting power in different resins, so you should pay attention to this when choosing a colorant. The particle size of the pigment is also related to the dispersibility. The smaller the particle size of the pigment, the better the dispersibility and the stronger the coloring power.
(3) Other properties of colorants should be understood. For example, for plastic products used in food and children's toys, the color materials should be non-toxic; for plastic products used in electrical appliances, color materials with good electrical insulation should be selected; For outdoor plastic products, color materials with good weathering resistance should be selected.
Second, the production process of color masterbatch The production process of color masterbatch is very strict, and the wet process is generally used. The color masterbatch is made by water phase grinding, phase inversion, water washing, drying and granulation. Only in this way can the product quality be guaranteed. In addition, while the pigment is being ground, a series of tests should be carried out, such as measuring the fineness of the sand slurry, measuring the diffusion performance of the sand slurry, measuring the solid content of the sand slurry, and measuring the fineness of the color slurry.
There are four methods for the production process of masterbatch:
1 Ink method, as the name implies, is a production method that uses ink color paste in the production of masterbatch, that is, through three-roll grinding, a low-molecular protective layer is coated on the surface of the pigment. The ground fine color paste is mixed with the carrier resin, and then plasticized by a two-roll plastic mill (also called a two-roll mill), and finally pelletized by a single-screw or twin-screw extruder.
2. The flushing method involves sanding the pigment, water and dispersant to make the pigment particles smaller than 1μm, and the phase transfer method to transfer the pigment into the oil phase, and then drying to obtain a masterbatch. Organic solvents and corresponding solvent recovery devices are required for phase inversion.
3. The kneading method is to blend the pigment with the oily carrier, and use the characteristic of the pigment to be lipophilic to flush the pigment from the water phase into the oil phase through kneading. At the same time, the surface of the pigment is covered by the oily carrier to stabilize the dispersion of the pigment and prevent the pigment from agglomerating.
4. In the metal soap method, the particle size of the pigment is about 1μm after grinding, and soap liquid is added at a certain temperature, so that the surface layer of each pigment particle is evenly wetted by the soap liquid to form a layer of saponification liquid. After being added, it chemically reacts with the saponified layer on the surface of the pigment to form a protective layer of metal soap (magnesium stearate), so that the finely ground pigment particles will not cause flocculation and protect a certain degree of fineness.
3. Precautions for the use of masterbatch
(1) The color masterbatch will absorb moisture after being stored for a period of time, especially PET, ABS, PA, PC, etc., so it must be dried according to the same process as the natural color pellet and meet the moisture content requirement. (2) Use masterbatch to match colors to achieve the desired color and luster must be very careful, color difference and shade changes often occur.
(3) The color masterbatch will react with other additives, so be careful when using it.
(4) Attention should be paid to the selection of the dilution ratio of masterbatch. If a high dilution ratio is selected, the production cost is lower, but it is also limited by the processing equipment.