CN1220741C

CN1220741C - Dechlorination of bleaching shellac

Info

Publication number: CN1220741C
Application number: CN 03135131
Authority: CN
Inventors: 陈晓鸣; 陈智勇; 李彬; 刘国兴
Original assignee: XILAIKE BIOLOGICAL SCIENCE AND TECHNOLOGY Co Ltd KUNMING; Research Institute of Resource Insects of Chinese Academy of Forestry
Current assignee: XILAIKE BIOLOGICAL SCIENCE AND TECHNOLOGY Co Ltd KUNMING; Research Institute of Resource Insects of Chinese Academy of Forestry
Priority date: 2003-06-03
Filing date: 2003-06-03
Publication date: 2005-09-28
Anticipated expiration: 2023-06-03
Also published as: CN1472274A

Abstract

The present invention relates to a method for dechlorinating bleached shellac. In the production of bleached shellac, dechlorination is carried out by using illumination; dechlorination is carried out by an infrared illumination device under the conditions of a wavelength of 650mm and intensity of 100000 lux to make a bleaching agent NaClO rapidly decomposed, and Cl2 is separated out; the chlorine content of an obtained product is below 0.8%, which achieves the chlorine content standard of a food additive; the thermal life, namely the thermal hardening time of the product at 170DEGC, is more than four minutes; the product can be stored for more than 2 years at a normal temperature under the condition of drying; the storage problem of the product is solved, and simultaneously, markets of the product are widened.

Description

Dechlorination method of bleached shellac

The technical field is as follows: the invention relates to a dechlorination method of bleached shellac.

Technical background: the shellac is a characteristic resource and an advantageous resource in Yunnan, but since the 80 s in the 20 th century, the processing technology of shellac products is far behind other countries, no new shellac product is developed, the product market is small, and the resource advantage is not really converted into the economic advantage. The existing production process of bleached shellac adopts sodium hypochlorite as a bleaching agent to bleach the shellac solution, and in the bleaching process, besides nascent oxygen released by the sodium hypochlorite destroys shellac chromogenic substances, lac resin molecules also react with the bleaching agent at the same time, and the addition and substitution depolymerization are carried out; the chlorine content of the product is 2-3.5% chloride ions, and the obtained bleaching gel with higher chlorine content can cause certain harm to human bodies when applied to food because the existing method for producing the bleaching gel has no specific dechlorination method or laggard method; meanwhile, the content of chloride ions directly influences the storage performance of the bleaching glue, the storage period is less than 6 months, the product is quickly agglomerated and deteriorated, the product does not accord with the trend of modern green and environmental protection, and the market capacity of the product is small.

The invention content is as follows: the invention provides a dechlorination method of bleached shellac, which is characterized in that in the production of the bleached shellac, the dechlorination is carried out by illumination, so that the bleaching agent NaClO is rapidly decomposed and contains Cl₂And the chlorine content of the obtained product is lower than 0.8%, the thermal life of the product at 170 ℃, namely the thermal hardening time exceeds four minutes, and the storage time is more than 2 years under the conditions of normal temperature and drying, so that the storage problem of the product at the normal temperature is solved, and the product market is expanded.

In the production process of the bleached shellac, in order to achieve the aim of dechlorination, the glue solution is bleached for 1 hour and then enters a dechlorination kettle, and the dechlorination is carried out by adopting illumination, under the conditions of 650nm wavelength and 100000 lux intensity, the dechlorination is carried out by adopting an infrared illumination device, and the reaction formula is as follows:

in the formula, sodium hypochlorite is extremely unstable and is rapidly decomposed into NaCl, [ O]and Cl2 ℃ × (O) under illumination, nascent state oxygen [ O]destroys shellac color developing substances to achieve the aim of bleaching, sodium chloride is dissolved in glue solution, and escaped chlorine can be collected and utilized again; and (3) stirring the glue solution for 25-45 minutes at a rotating speed of 80r/min while dechlorinating by illumination.

The chlorine content of the bleached shellac product obtained after illumination dechlorination is lower than 0.8 percent and reaches the chlorine content standard in food additives.

Description of the drawings: FIG. 1 is a process flow diagram of a dechlorination method of bleached shellac according to the present invention.

The detailed description is to be read in connection with the appended drawings: dissolving shellac to obtain shellac solution and controlling the concentration to be 10%; slowly adding sodium hypochlorite bleach with effective chlorine content of 10% into bleaching tank, wherein the sodium hypochlorite dosage is determined by shellac bleaching index, such as shellac produced by Cochloa chinensis, color index No. 16, and sodium hypochlorite dosage is 60% of shellac if the hot ethanol insoluble substance is below 4%. 100kg of shellac needs 60kg of sodium hypochlorite with 10 percent of available chlorine content, the shellac is added for half an hour, the shellac is added into a dechlorination kettle after being bleached for 1 hour, the shellac is irradiated by infrared light, the light intensity is controlled at 10 ten thousand lux, a stirrer is started at the same time, the shellac is stirred at the rotating speed of 80r/min for about 40 minutes, dechlorination glue solution is tested by starch test paper, when the test paper does not change color, the sodium hypochlorite in the shellac solution is decomposed, then neutralization is carried out by a known method, and the shellac is washed by water to obtain.

The invention has the advantages or positive effects that:

the invention is applied to the production of refined bleached shellac, and compared with the prior production process, the invention has the following positive effects:

(1) the bleaching and dechlorinating processes are completed in a short time.

(2) The thermal life of the product was over 4 minutes at 170 ℃.

(3) The chlorine content of the product is lower than 0.8 percent and is superior to the national standard.

(4) The storage period can reach 2-3 years at normal temperature.

Claims

1. A dechlorination method of bleached shellac is characterized in that in the production of the bleached shellac, the concentration of shellac solution is controlled to be 10%, sodium hypochlorite with 10% of available chlorine content is slowly added, and the use amount of the sodium hypochlorite is determined by the bleaching index of the shellac, and the dechlorination method comprises the following steps: bleaching for 1 hour, then putting the mixture into a dechlorination kettle, performing light dechlorination under the conditions of the wavelength of 650nm and the intensity of 100000 luxes, and stirring for 25-45 minutes at the rotating speed of 80 r/min.

2. Dechlorination process according to claim 1, characterised in that: the amount of the sodium hypochlorite is determined by the bleaching index of the shellac, and the proportion of the sodium hypochlorite in the shellac solution is correspondingly increased along with the increase of the color index of the shellac raw material.