Development of super - jumbo cocoons of the silkworm for thick cocoon filaments

在目前的许多家蚕品种中，茧丝的大小约为2.5否认。为了获得厚实的茧丝，并利用其生产具有特色感觉的真丝织物，对人工饲料饲养的1日龄4-Enstar幼虫进行了研究，发现获得巨型蚕茧的适宜条件是每头幼虫皮下喷施20-100杯保幼激素。从而延长了4龄幼虫的跨度，增加了新脱壳的5龄幼虫的体重，最终获得了巨型茧。例如，在生产通常较粗的蚕丝(约3.8纤度)的特定家蚕品种中，使用保幼激素后获得的巨型蚕茧的茧丝纤度在4.6-4.7纤度之间。随后，用不同品种的不同类型的蚕茧分别纺制了27个纤度较大的蚕丝，并对其物理性质进行了检测。结果表明，以粗茧丝为原料，蚕丝的伸长率变大，单位纤度的蚕丝强力变小，杨氏模数变小。换言之，当使用大纤度的蚕丝时，可以生产出柔韧性高的丝线，在物理性能上也被认为是粗丝线的优势。此外，利用大量的巨型蚕茧，可以纺出27个纤度的生丝。整整一百根生丝被并纱，捻成S式的捻线，然后脱胶。然后用这样得到的丝线编织(天际线)。这种针织在几个方面优于普通产品，根据面料制造商和质量评估专家的意见，这些丝线的性质可以被视为新产品的纺织材料。

The size of cocoon filament is approximately 2.5 deniers in many of the current silkworm races. The present study was undertaken in order to obtain thick cocoon filaments and, using them, to produce silk textile of characteristic feeling.It was found that the suitable condition for obtaining jumbo cocoons was cutaneous application of 20-100 mug juvenile hormone per larva to the, one-day-old 4th-enstar larvae reared on artificial diets. Thus, the span of the 4th instar was elongated, the weight of the newly-ecdysed 5th-instar larvae increased, and finally jumbo cocoons were obtained. For instance, the size of cocoon filament of jumbo cocoon obtained after the application of juvenile hormone ranged from 4.6 to 4.7 deniers in a specific silkworm race which produced usually thick cocoon filament(ca. 3.8 deniers).Subsequently, many silk threads of 27 deniers were reeled using various types of cocoons of different races, respectively, and their physical properties were examined. As a result, the rate of elongation of silk thread became large, the strength of silk per unit size of filament became small, and its Youngs modulus became small, when thick cocoon filaments were used as materials for silk threads. In other words, when large size of cocoon filament was used, the silk thread of high flexibility was produced, and an advantage was also recognized in the physical properties as a thick silk thread.Furthermore, using a number of jumbo cocoons, raw silks of 27 deniers were reeled. Exactly a hundred threads of the raw silks were yarned in doubling, twisted into a S-twist, and degummed. Then a knitting(Tenjiku)was made using the silk threads thus obtained. This knitting was superior to the usual goods in several respects, and according to the opinions of the fabric maker and the specialist of quality estimation the nature of those silk threads could be appreciated as textile materials for new goods.