Two different types of western silk reeling system played an important role in development of Japanese silk manufacturing industry in modern Japan. One of those is Italian type silk-crossing system and the other is French type silk-crossing system. In this study, we focused on the Italian type silk-crossing system and examined 68 academic documents and technical books for raw silk production which published from the Meiji era, the Taisho era to the Showa era to analyze changes of the technology. And we compared with the Italian type silk-reeling process and French type silk-reeling process to realize a fundamental difference between two systems. As a result, Italian type silk-reeling process in Japan is the same as French type silk-reeling process, it turned out that factors of the technological transitions were attributable to adaptation of Japanese silk mills to the introduced western style technology, quality of raw material cocoon and changes of the global market structure and needs. Furthermore, based on the description of “Kenneru-shiki Tomoyori-shiki Hikaku shiken” (Meiji 39) etc., we analyzed the relationship between ratio of crossing density, efficiency, and quality, which are parameters that indicate the process condition, and confirmed the feature differences between the two mechanisms. From these results, we found that the Italian type silk-reeling process was a mechanism that had the ability to change and adapt flexibly to changes in the market structure. Therefore, it was possible to consider that the French type silk-reeling process could not maintain the superiority in which both efficiency and quality were taken into consideration compared to the Italian type silk-reeling process, and that it led to the disappearance at the end of the Taisho era.
Today, the purpose of raising silkworms is to be used for edible or medical purposes, not for the purpose of producing raw silk. In addition, filature technology using mechanical machine is still being studied and developed, but the study of hand reeling filature technology is in an insufficient state. This situation limits the execution of the work due to the absence of raw silk materials in the areas where the silk textile relic are reproduced and restored or where a small quantity of multi-product raw silk is required. In this research paper, we tried to solve this problem by investigating and analyzing the filature technology using hand reeling tools through the literature left by the ancestors in Korea.
The literature on the filature reveals that the first method is to improve the storage stability of the harvested cocoons, the second is to kill the pupa of the cocoons to make the raw silk of long fibers, which is the advantage of the raw silk, the third is how to sort the cocoons before cocoon cooking, the fourth is how to cook the cocoons to soften the cocoon layer before reeling, the fifth is method to how to use what kind of water for silk reeling and how to treat the water, for cocoon cooking and reeling, the sixth is how to find the suitable reeling temperature adapted to reelable cocoons and un-reelable cocoons. We found that the filature methods have been done scientificaly from old days.
When attempting to restore a silk textile antiquity, it is necessary to make a thread suitable for the characteristics of the silk textile. Examined a silk reeling method by various manual works through the ancient literature which described a silk reeling method by the manual work and performed silk reeling of those raw silk. Furthermore, in order to investigate the effect of the reeling method of these ancient literatures on the raw silk, a comparative test was conducted on the tension, lustre and color difference for the current silkworm race. As a result, it was found that the elasticity was affected by the pupa killing method and silkworm race, the tenacity was affected by the reeling tools and silkworm race, and the Young's modulus was influenced by the reeling tools. It was also found that the luster was affected by the reeling tool and the silkworm race, and the color difference was affected by the silkworm race, the reeling tools, cocoon-preserving methods and pupa killing methods.
The effect of protein coating on the cohesion of raw silk made from low-temperature cooked cocoons was assessed. An experimental coating-system was constructed and installed on a reeling machine. The cocoons of Gunma×200, a commercial silkworm race, were cooked using a low-temperature cocoon cooking method and analyzed. Coating was performed in two different places: before and after the kenneru-system. In the case of sericin coating, natural glue proteins of cocoon filaments, the native sericin showed significant improvement in the cohesion of raw silk treated before and after the kenneru-system. On the other hand, the sericin extracted at 121°C did not show any effect on the raw silk cohesion. However, the sericin extracted at 115°C showed a slight improvement in cohesion of raw silk coated after the kenneru-system. The composition of the sericin protein sizes in the prepared sericin solutions was different, and high molecular-weight sericin protein was apparently effective in improving the raw silk cohesion. In addition to sericin, the effect of the gelatin coat on the improvement of raw silk cohesion was assessed. Application of more than 5% gelatin coating before the kenneru-system and 3% gelatin coating after the kenneru-system resulted in significant increase in raw silk cohesion. Furthermore, the gelatin coating did not affect the degumming process. The strength of coated raw silks decreased; however, the strength of the silk fiber itself was not affected.
A new concept of production of bulky void silk has been developed by introducing PVA yarn in the process of silk reeling in the modified multiend reeling machine. The bivoltine cocoons along with Japanese PVA yarn is used for the production of void silk. Using the Box and Behnken design of experiments the process variables viz., Number of cocoons, croissure length, reeling basin water temperature and reel speed have been standardized with 27 combinations of experiments. The study indicates that process variables significantly influence the reel performance and quality of void silk produced viz., reelability, raw silk recovery, waste percentage on silk weight, average size and yarn thickness. The void silk produced was twisted and later degummed and the quality parameters viz., denier, tenacity, elongation, yarn thickness and bulk density were studied. The results indicate that process variables significantly influence the quality characteristics of twisted and degummed void silk. Based on the response optimization in statistical analysis, it was observed that 30 bivoltine cocoons reeled per end with 6 mm croissure length, 50°C basin temperature and reel speed of 100 m/min is ideal for the production void raw silk on modified multiend reeling machine. The void silk was used as weft in the production of bulky silk fabrics.
Winding performance of the raw silk skeins produced in reeling machinery is affected with the prevailing conditions of the twisting industry in India. It was thought to improve the winding performance of the raw silk by treating the raw silk using steam before converting the skeins on to bobbins on winding machine. Standardization of pre steaming conditions viz., pre steaming temperature and duration for both the bivoltine and multibivoltine raw silk were carried out using central composite experimental design. It was observed that using saturated steam, steaming the silk skeins at 60ºC temperature inside the vessel (Steaming temperature is 95 ºC) for 15 minutes duration was found to improve the winding performance and elongation characteristics of bivoltine raw silk significantly and for 10 minutes duration with same conditions found to be suitable for multibivoltine raw silk. The methodology can be easily adopted in all the twisting units as steaming chamber is supplied along with the twisting machinery package.
To investigate the influence of cocoon filament characteristics in the production of silk fabrics, raw silk with reeling tension of less than 0.4 gf/d (LT) was used to produce a low-reeling-tension silk fabric (LTF). For comparison, silk fabric using high-reeling-tension raw silk (HT) was also produced (HTF).
We observed the raw silk with a scanning electron microscope, and examined the shape of the thread and the mechanical and heat transfer properties of the silk fabrics. We also investigated the influence of the raw silk reeling tension on the physical properties of the silk fabrics. The LT exhibited voids, the arrangement of the cocoon filament was uneven, and crimps and curling were detected in the cocoon filament. We confirmed that the shape of these threads was preserved in the LTF. The air permeability of LTF was large compared to that of the HTF, and the glossiness value was low. Shearing was difficult, and the LTF recovery characteristics were low in comparison with the HTF. In addition, the LTF was harder to shear, its recovery characteristics were low, when compared to the shearing properties of LTF containing HTF, and its surface was more uneven than that of the HTF. Both the q-max values and thermal conductivity were less in the LTF than the HTF, suggesting that there was little heat movement in the LTF. It was revealed that the shape of the thread had an influence on these silk fabric properties.
Silk-fibroin sponges have been studied for use as effective biomedical materials, specifically as scaffolds for cartilage tissue regeneration and wound covering. Water absorption properties of fibroin sponge are important for developing new biomedical and cosmetic applications. Hydrophilic polymer (PEG) composites and pore size control by altering fabrication processes can control water absorption properties. To evaluate water absorption properties, we introduced a parameter based on water contact angle measurements. This parameter, which represents the water sorption velocity, can indicate different water absorption properties of small areas in one sponge material. Several fibroin sponges with different pore sizes were prepared by changing fabrication processes. Higher water absorption velocity was observed on fibroin sponges with larger pores. Furthermore, PEG composite fibroin sponges were fabricated with incorporation of PEG caused by increasing the water absorption velocity. These results indicate that fabrication processes can control fibroin sponge water absorption properties.
The fibrillar structure of Bombyx mori silkworm silk is well known. However, its hierarchical details, such as the average dimensions of nanofibrils and bundles (i.e. fibrils) as well as nanofibril aggregation manner and orientation level, remain incompletely understood. This study investigated the fibrillar structure in B. mori silkworm silk by using small-angle X-ray scattering (SAXS) analysis. SAXS analysis revealed bundles comprising hexagonally packed nanofibrils. To our knowledge, this has never been reported in morphological observations of B. mori silkworm silk or any other native silks. The average diameters of nanofibrils and bundles were approximately 4.7 and 54 nm, respectively. Our results demonstrate the potential of SAXS analysis for investigating the hierarchical fibrillar structures of native silks.
We have previously produced a transgenic silkworm with posterior silk glands that expresses cypovirus 1 polyhedra-encapsulated cytokines, for which the activity remains stable in the individual organ and processed silk guts. In the present study, we describe a method that utilizes a specific lysis solution to isolate human-FGF-2-encapsulating polyhedra produced in the middle silk glands of fifth instar silkworm larvae. These polyhedra exhibited the biological activity of FGF-2, inducing the signaling events of MAP kinase phosphorylation in proliferating NIH-3T3 cells. This study demonstrates the potential use of polyhedra prepared from silkworm organs as effective biomaterials in tissue engineering.