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

在目前的许多蚕种中，蚕丝的大小约为2.5旦。为了获得较厚的蚕丝，并利用其生产具有特色触感的丝织品，进行了本研究。结果表明，人工饲料饲养的1日龄4龄幼虫，每只幼虫皮肤施用20 ~ 100马克的幼虫激素，可获得大茧。因此，4龄幼虫的跨度被拉长，新蜕皮的5龄幼虫的重量增加，最终得到巨型茧。以某家蚕种为例，施用幼体激素后获得的巨茧的茧丝大小在4.6 ~ 4.7旦之间，产生的茧丝通常较粗（约5 ~ 6旦）。3.8否认者)。随后，分别用不同品种的蚕茧纺成27旦的丝线，并对其物理性能进行了检测。因此，当使用粗蚕丝作为丝线的材料时，丝线的伸长率变大，丝的单位尺寸的强度变小，其杨氏模量变小。换句话说，当使用大尺寸的蚕丝时，产生了高柔韧性的丝线，并且在物理性能上也被认为是粗丝线的优势。此外，使用大量的巨型茧，纺成27旦的生丝。整整一百根生丝被捻成两股，捻成s型，然后脱胶。然后用这样得到的丝线编织（天井）。这种编织在几个方面优于一般的产品，根据织物制造商和质量评估专家的意见，这些丝线的性质可以作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.