• International Journal of Industrial Entomology and Biomaterials
• /
• v.28 no.1
• /
• pp.19-24
• /
• 2014

Silk has always been one of the most favored textile materials. Fully degummed silk fiber (i.e., silk fibers without sericin) shows better luster than raw silk fiber (with sericin); it is also softer. On the other hand, raw silk fiber feels cooler because of the presence of sericin, making it useful as a textile for the summer season. Recently, partially degummed silk has attracted researchers' attention because it provides better luster, feel, and dyeing properties. However, the partial degumming of silk is very difficult because it results in inhomogeneously degummed fiber. In the present study, silk yarns were degummed with surfactant aqueous solutions and the effects of each surfactant on the degumming ratio, crystallinity, and homogeneity of the degummed silk yarn were examined. The degumming ratio and crystallinity index of silk yarn varied depending on the type of surfactant. On the whole, anionic surfactants resulted in higher degumming ratios and better homogeneity than nonionic surfactants.

• Textile Coloration and Finishing
• /
• v.21 no.1
• /
• pp.67-72
• /
• 2009

To investigate the strong and effective sericin fixing agents and conditions, raw silk fibers were treated with the mixtures of urea-formalin, thiourea-formalin and melamine-formalin as sericin fixing agents, respectively. And the treated raw silk fibers were degummed by the degumming liquors of alkaline detergent and sodium carbonate to confirm the hardness of sericin fixation. The weight of raw silk fibers was decreased in the process of sericin fixation treating at 80$^{\circ}C$ for 60min. The effective sericin fixation was obtained by treating at $60{\sim}80^{\circ}C$ for 15min with the mixture of melamine and formalin. The mixture of melamine and formalin showed an outstanding ability of sericin fixation because the three amino groups of melamine were able to cross-link the hydroxy amino acids of sericin such as serine with the assistance of formalin.

• Journal of Sericultural and Entomological Science
• /
• v.35 no.1
• /
• pp.52-59
• /
• 1993

Raw silk degumming, by which the sericin and other marterials are eliminated from fibroin, is very essential process to produce silk fabrics. Alkali chemicals and enzymes have been used for the silk-degumming process. In this paper, the effect of heat treatment was investigated on silk fibers degummed by two different methods, soap and enzymatic degumming method. The difference between these two degumming methods was analyzed on the basis of results of mechanical testing, thermal analysis and intrated spectroscopy. The tenacity and the elongation of silk fiber are decreased by the heat-treatment in wet state. This tendency is observed in both cases of two degumming methods. The peak temperature in DSC analysis, which is attributed to thermal decomposition of silk fiber, was shifted to higher value with the heat-treatment temperature for the soap degummed silk fiber, however, it was not for the enzymatic degummed one. The IR crystallinity of soap digummed silk fiber is increased with the heat-treatment temperature, while that of enzymatic degummed fiber is not.

• Textile Coloration and Finishing
• /
• v.22 no.4
• /
• pp.349-355
• /
• 2010

To investigate the half-degumming of raw silk, the degumming was carried out with soap or sodium carbonate or sodium bicarbonate and some mixed agents at $80^{\circ}C$ for 15 and 30 minutes. With soap of 20~25%o.w.f. degumming losses were about 7~12%. Degumming losses with sodium carbonate of 2~5%o.w.f. were about 6~15%. And about 6~12% wright losses were observed in the degumming with sodium bicarbonate of 20~30%o.w.f. In the degumming with the mixed degumming agents of soap and sodium carbonate, degumming losses were 9~15% with 5%o.w.f. soap and 2~5%o.w.f. sodium carbonate. Sodium carbonate was more effective on the removal of sericin from raw silk than soap. During drying generally half degummed silk yarns stuck together to result in harsh and hard lumps by the adhesion and solidification of the residue sericin of partially degummed silk. Sodium hydrosulfite in degumming agent effectively protected the adhesion of half degummed silk yarns.

• Journal of Sericultural and Entomological Science
• /
• v.7
• /
• pp.65-74
• /
• 1967

This work has been carried out to find the fundamental reasons of raw silk size nonuniformity by studying with the physical nature and its bave formation through the worm spinnerate with anatomical device. Mean time, the uniformity improving method is also attached to this paper after throughfall theoretical study. 1. According to the anatomical study of the silkworm spinnerate, the physical form decides the fiber cross section and also spinns more finner size as the spinning is continued collaborating with the muscle pressure and decrease of liquid silk in the silk gland. 2. The bave size deviation of the Korean cocoons have shown a little difference among the varieties, but, they are conclued as 0.58 denier in average which caused some size deviation of the raw silk inevitably. 3. The raw silk nonuniformity increases when the cocoon have size is not suitable with the proposed raw silk size. 4. The nonuniformity is also increased very much during the filature process in case of poor technical work, but even if we do our best, the best result is found as 30 percent improvement which is still worser than the natural cocoon size deviation. 5. It is required to be careful for the selection of silkworm variety in order to improve the nonuniformity of raw silk so that the bave size be suitable for the proposed silk. 6. The definite size silk reeling method could made better uniform silk, 20 percent at least, than the definite cocoon number silk reeling method. 7. A newly developed denier(21d) gauge was applied for the multiends type silk reeling machine which is widely used in Korea, and the result of the method showed 1.30 denier size deviation, but, in case of no use of it was 1.57 denier size deviation, that is, it could improve two grades more than the normal reeling method.

• Journal of Sericultural and Entomological Science
• /
• v.4
• /
• pp.63-68
• /
• 1965

This treatise was carried out to study the hereditary phenomenon of silk lousiness and the interaction of genes related with silk lousiness. It was also studied how to improve the silk lousiness of general raw silk by refining process because the selective process was found as unsatisfactory method. The conclusions reached were as follows. A. Conclusions related with genetic problem. 1. The decreased effects of the lousiness were 11 % in the F$_1$ hybrids. 2. Lousiness was considered to inherit as the incomplete dominance. 3. The effects of the lousiness gene were additive, and the lousiness of raw silk might be influenced by more than two genes. 4. The quantitative characters of cocoons were not genetically correlated with the occurrence of lousiness. 5. Lousiness could not be said to occur more in the heavy-cocoon strains. 6. The microscopic lousiness test of this paper showed the same result of the international exforiation test. B. Conclusions related with lousiness improvement. 1. Raw silk was able to be refined by the employment of 0.2% cationic softener solution for 30 minutes at 95$^{\circ}C$, supressing the occurrence of lousiness. 2. Anionic chemical softener was not available for silk refining process. 3. The above cationic softener refining prosess did not cause any physical defect for the silk fiber. 4. Soap refining process caused silk lousiness easily.

• Journal of Sericultural and Entomological Science
• /
• v.2
• /
• pp.1-31
• /
• 1962

The purpose of this treatise is to prove the presence of cystine in silk fiber through wide sampling throughout all the sericultural processes of Bombyx mori.; also to show that disulfide cross linkages exist in the silk fiber. The conclusions reached were as follows: 1. Crystalline cystine was obtained from silk fibroin using Folin's Method. 2. Analytical data showing the cystine content of silk fiber and its related materials were obtained using Sullvan's Method as follows: Material Percent Cystine A. Mulberry leaf protein 0.175 B. Silkworm egg 0.33 C. Silkworm Body, matured, fat extracted, without silk gland 0.41 D. Silk gland, matured 1.23 E. Silkworm feces none F. Silkworm pupa, fat extracted 0.30 G. Silkworm moth, fat extracted 0.60 H. Raw Silk 0.22 I. Fibroin 0.175 J. Sericin 0.30 3. The presence of cystine in the silkworm was substantiated the existence of 0.175 % methionine in mulberry leaves and 0.12% methionine in the silk gland. 4. Part of the sulfhydryl compounds in the silk gland is believed to transfer to serine and methionine, with the former being secreted into the liquid silk finally as silk fiber and the latter used for nutritive purposes in the growing of silk gland tissue. 5. The cystine content is variable by mulberry species, silkworm species, sex, breeding process, and other culturing environments. 6. Hybrid silkworms require more nutritive amino acids for effective growth than the original parents, and secrete less of them as silk fiber. 7. From such an observation, the amino acid composition of silk fiber is believed to be fairly flexible. Cystine if included in the amorphous part of the fiber, especially in sericin. 8. The result from enriching the silkworm diet with pure cystine or wool cystine did not result in any advantage, therefore it is believed that the natural cystine and methionine contents in the mulberry leafaregoodenoughforsilkwormnutrition. 9. The disulfide cross linkage in silk fiber was verified by using the Harris Method. Contraction took place following the treatment of the fiber with various salts and acids. Comparisons were made with wool fiber. 10. During these experiments, the fibrious structure of silk fiber and the net-globular liquid form were photographed microscopically. It is believed that the globules of liquid silk are net-formed by the inter attraction of the OH ion of the globular peptide and the H ion of water as shown by the hair cracking behavior of the film. The net-globular protein precipitation from the mulberry protein solution showed that mulberry is a proper diet for the formation of fibrous protein in the silk fiber. 11. The significance of the presence of cystine in silk fiber as emphasized in this paper should result in modification of the general conception that cystine is absent from this fiber. NOTICE: A part of this treatise was presented at the annual Korea Sericultural Society meeting held in 1961.

• Journal of Sericultural and Entomological Science
• /
• v.13 no.1
• /
• pp.73-78
• /
• 1971

The purpose of this study is to find out the method of conditioned weight test by which the dealing weight of raw silk can be calculated from true fiber in order to do the fair trading. The results of this study were as follows. 1. It is more reasonable than the current test that conditioned weight as a dealing weigh can be calculated by boil-off and moisture regain which is a percentage of boil-on and moisture regain to net weight. Because the boil-off and moisture regain can show directly the amount of true fiber and reproductibility in raw silk. In this study the boil-off and moisture regain is to take dry weight after boiling-off from net weight. 2. To calculate the conditioned weight from boil-of and moisture regain it would be proper that the standard additional ratio is 44 per cent of dry weight after boiling-off. 3. Boil-of percent of the sizing sample skein used in the size test did not show a statistical significance comparing with the boil-off percent of sample skeins (24 skeins) which may represent that of a lot. To observe this result boil-off percent of the sizing sample skein may represent that of a lot. 4. In Korea if conditioned weight test substitute for test of boil-off and moisture regain, we make a profit of two billion won in a year at the current market-price.

• Fashion & Textile Research Journal
• /
• v.9 no.2
• /
• pp.243-248
• /
• 2007

This study is about the fabric attached to the relics excavated from the Shimchun-ri tomb of the 4th century and the Moonsan-ri tombs of the 5th century. We studied 5 pieces of fabric from the Shimchun-ri tomb: one piece was silk and the other four pieces were hemp. We were able to observe 8 pieces from the four tombs in Moonsan-ri, All of them except one ramie were silk. The two kinds of bast fiber found in the tombs of Shimchun-ri and Moonsan-ri were hemp and ramie, and they were found to be plain woven with S-twist thread which thickness is uneven. The density was more fine compared to the hemps found in the Kaya or Shinra tombs of the similar era. All of the silk textiles found in the Shimchun-ri and Moonsan-ri tombs used non-twisted thread, and were plain woven. Also, we found degummed and raw silk from the tombs. The average density of the silk textiles from these tombs are similar to other areas of the same time, and studies show that they used non-twisted thread in plain woven silk found in other tombs. Therefore, we can conclude that they usually used non-twisted thread when producing silk textiles.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.24 no.1
• /
• pp.17-21
• /
• 2012

The effect of cultivation season on the cocoon filament quality of authorized silkworm variety, GoldenSilk was examined with cocoon filament character, reeling character, and fiber character during 3 years. In cocoon filament character, filament length of spring and autumn cocoon was 979 and 879 m, respectively. Cocoon filament weight of spring and autumn cocoon was 33.1 and 26.5 cg, which is lower than that of general bivoltine strain, BaeGokJam. Raw silk percentage of spring and autumn cocoon was 15.65 and 13.77%, respectively. In reeling character, reelability showed similar trend regardless of cultivation season and strain. However, the length and weight of non-broken filament of spring season were slightly higher than those of autumn cocoon. Cultivation season did not affect on the fiber characteristics such as clearness and neatness, lousiness, and degumming loss. In cocoon character, filament length, size, and weight, spring cocoon filament showed higher value than autumn cocoon, but lower than authorized general silkworm varieties. In reeling characteristics, non-broken length and weight showed the similar trends with the cocoon filament character. However, the reelability of GoldenSilk cocoon was not affected by cultivation season. The reelability of GoldenSilk cocoon was also similar with that of authorized general one. Fiber character including clearness and neatness, lousiness, and degumming loss was also similar regardless of the rearing season and different strain.