▎ 摘　　要

NOVELTY - Method comprises a twin-screw extruder used to prepare batch under a combination of special screw elements and special screws, and the special screw elements include conveying blocks and conventional kneading blocks, special multi-head kneading thread block, and toothed disk, the specific screw combination conditions comprise 75/75A, 90/90, 90/90, 90/90, 75/75, 45/45, 45/45, K30/ 5/75, K30/5/45, K30/5/45, K30/5/45, K30/5/45L, 30/30L, 75/75, 75/75, 90/90, 90/90, 90/ 90, 90/90, DKB90/7/75, DKB90/7/75, DKB90/7/75, DKB90/7/75, DKB90/7/75, K45/5/75L, K90/5/45, 60/ 60, K45/5/75, K90/5/45, K90/5/45, K90/5/45, 30/30L, 60/60, 60/60, 60/60, 60/60, K45/5/ 45, K45/5/45, K45/5/45, 60/60, 60/60, C1, C2, C1, CY, 90/90, 75/75, 75/75, 75/75, 75/75, 75/75,75/75,60/60,60/60; where K is a conventional kneading thread element, DKB is a special multi-head kneading thread element, L is a reverse thread block, C1 and C2 are toothed discs, and CY is a circle plate. USE - The black masterbatch is useful for packaging of high-end lithium-ion batteries (claimed). ADVANTAGE - The method has a low gloss, but also gives a soft effect, evenly distributed black additives, without graininess, and easy to identify process defects in production. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a matte black polyamide film for lithium-ion battery comprises provided with a matte black polyamide upper surface layer, a polyamide middle layer, and a black polyamide lower surface layer from top to bottom, the matte black polyamide upper surface layer comprises 1-20 pts. wt. of black masterbatch, 1-20 pts. wt. toughening agent, 1-20 pts. wt. matt agent, 1-5 pts. wt. additive, 35-96 pts. wt. polyamide, the polyamidemiddle layer is 100 pts. wt. polyamide, the black polyamide lower surface layer comprises 1-20 pts. wt. black masterbatch, 1-20 pts. wt. toughening agent, 1-5 pts. wt. additive, 55-97 pts. wt. polyamide, the black master batch is black master batch prepared by the method; and (2) preparation method of matte black polyamidefilm for lithium ion battery comprises drying all raw materials, controlling the water content of the raw material below 600 ppm, (ii) mixing the raw materials of the upper surface layer, the middle layer and the lower surface layer and uniformly dispersing by the high speed stirrer, melting, plasticizing and extruding at 230-290 degrees C by the extruder, flowing out through the T-shaped mold head, (iii) using a low pressure air knife to attach the melt on the cold drum to form a thick sheet, where the thickness of the thick sheet is 100-400 m, the temperature of the cold drum is 10-45 degrees C, (iv) immersing the thick sheet in the water tank with the temperature of 20-100 degrees C to pre-treat, (v) heating the thick sheet, using Bruckner magnetic suspension synchronous biaxially stretched device for synchronous biaxially stretched of polyamide film, where the stretching temperature is160-220 degrees C, the stretching rate is 2.7 asterisk 2.7 to 3.6 asterisk 3.6, (vi) heat-setting the stretched film, where the shaping temperature is 170-235 degrees C, the shaping time is 5-50 seconds, cooling film and corona treatment, the corona processing power is 8-15 Wminutes/m2, and coiling, (vii) cutting the rolled bidirectional stretch polyamide film according to the requirement and obtaining the matte black polyamide film and film thickness of 10-60