There are four grades of white filaments: first class, first class, qualified and processed. This grade is divided according to indexes such as fiber content and filler, and cannot be randomly marked. Take first-class products as an example, to reach this level, it must be 100% (note: the standard does not say that it must be 100%, only the type must be marked on the label); The color difference of the filler is not less than grade 4, the thickness is uniform, and the difference rate is not more than 10%; Quadrangle quadrangle, angular quality difference rate is not less than -20%, in addition to the compression rebound rate, tire color fastness requirements and first-class products, qualified products are different, only to achieve these indicators, can be called superior.
A bed of high quality, have qualification to call "excellent grade", "special grade" or "first grade", must use "long or medium long silk floss" be raw material. If it is "short silk", even if the workmanship is exquisite, can only be called "qualified"
Raw silk refers to the industrial silk, commonly known as white factory silk, which is spun by drawing cocoon silk from the cocoon layer through a certain process and combining and gluing several cocoon silk according to the requirements of linear density. Raw silk is the raw material used in the production of silk thread or fabric. It has beautiful luster, soft and elastic feel. The processed silk products are colorful, rich in variety and good in wearing performance, which are deeply welcomed by consumers.
A. The task of raw silk production is that there are many kinds of cocoons and the cocoon quality varies greatly. Single silk reeled is very thin, low strength, need to be combined spinning into silk, these tasks through the raw silk production process system to complete.
2. White silk production of raw materials and cocoon processing 1. Raw silk production of raw materials reeling raw silk raw materials are mainly home cocoon, also known as mulberry cocoon. Each cocoon includes five parts: cocoon coat, cocoon layer, pupa lining, pupa and molting. The cocoon coat is the outer layer of the cocoon, which accounts for about 2% of the cocoon weight. The cocoon layer is used for reeling silk, and its weight accounts for about 50% of the cocoon weight. Pupa lining is the filaments of the innermost layer of cocoon, which accounts for 2.5% of cocoon weight. Silkworm pupae is used to pinch pupa oil and pupa protein, accounting for about 45% of the cocoon weight. Molting weighs very little and is useless. Cocoon shape, color, uniformity, uniformity, wrinkle, thickness, tightness, ventilation and other characteristics, directly affect the quality and efficiency of silk production.
2. Cocoon processing home cocoon fresh cocoon can not be stored for a long time, must be timely pupa killing and drying, that is, the primary processing of the cocoon. The purpose of pupal killing is to prevent moth, maggots and cocoon layer from being reeling. The purpose of drying is to remove some water, avoid mildew and deterioration, facilitate storage, and at the same time make sericin suitable denaturation, enhance the resistance of cocoon layer to cocoon cooking, and meet the requirements of reeling silk. Pupa killing and drying are carried out in a cocoon drying machine that USES hot air for drying. The whole process is divided into three stages.
1) preheating stage: the temperature gradually increases, the hot air enters the cocoon chamber, and the live pupae is roasted to death after being heated. The wax layer on the surface of the pupa body is destroyed.
2) the constant speed drying stage: to continue to heat up to 100 ~ 110 ℃ in dry treasure, cocoon layer internal moisture to gradually shift to the surface, and constantly send out, cocoon layer is a layer of water film surface form, the evaporation rate remains the same.
3) deceleration drying stage: with the decrease of cocoon moisture content, the evaporation rate gradually decreases until the water vapor film on the cocoon surface disappears and the evaporation stops. The moisture content of chrysalis in fresh cocoon is 73% ~ 77%, the moisture content of cocoon layer is 13% ~ 16%, and the moisture content of dried cocoon is 9.1% ~ 10.7% after drying. The cocoon drying process takes 5 to 6 hours. The process is generally carried out in the cocoon purchase station. Cocoons must be properly stored and preserved after drying before being put into silk production to prevent mildew, insect and rat damage. Cocoon storage must have certain temperature and humidity conditions, the establishment of safety inspection system, in order to preserve the cocoon quality.