Vacuum freezing dried extraction method of natural plant dye

Abstract

The invention provides a method of extracting natural plant dye, which uses dye-containing plant as raw material to obtain pulverulent natural plant dye by water extraction, vacuum cooling and drying. The method includes steps: (1) abstraction: weight ratio of water and plant of 1:5-15, extraction temperature of 40-90 DEG C, extraction time of 20-60 min, extraction frequency of 1-3, combining extraction liquid; (2) precooling: temperature of minus 20 - minus 50 DEG C, time of 1-5 h; (3) vacuum freeze drying: temperature of minus 45 - minus 55DEG C, vacuum degree of 10-20Pa, time of 15-20 h. Outstanding character of the invention is: 1. preparing pulverulent product and not destructing original biochemical property of natural plant dye; 2. solving problem of bad staining reproducibility of natural plant dye liquid extracted by existent technique and increasing staining reproducibility of the natural plant dye liquid; 3. solving problem of conservation of the natural plant dye liquid and capable of storing the natural plant dye liquid for a long time.

Description

Technical field [0001] The present invention relates to dyes of natural origin prepared from natural raw materials. In the preparation process, only water is used to make a solution, and then the powdery product is extracted by a drying method. Background technique [0002] Natural plant dyes are non-toxic, ecological, soft in color, natural and distinctive, and they have good environmental compatibility and medicine health care properties, and have broad development prospects. Judging from the current dyeing process of natural plant dyes, most of the dyes are extracted by heating with water or solvent, and the dye liquor is directly used for dyeing of textiles ([1] Jia Na, Gong Jianpei. The extraction and extraction of yellow pigments from common plant dyes Dyeing, dyeing and finishing technology [J], 2006, Volume 28 (3): 24-27; [2] Chinese Invention Patent Publication Number: CN 1204667, a natural plant yellow pigment for carpets and its preparation and use methods ). This meth...

AI Technical Summary

Problems solved by technology

Furthermore, due to the instability of some pigments in natural plant dyes, obvious color differences may also appear when repeated experiments are carried out under different experimental conditions. In practical applications, it is basically necessary to re-extract and filter every time, resulting in The pigment content cannot be quantified each time, and the reproducibility is even more difficult to achieve

[0003] At present, there is a lack of mature methods for extracting natural plant dyes and natural plant dye products with stable quality and excellent performance.