Manufacturing method of processed silk yarn

Abstract

This invention provides a method for producing processed silk yarn suitable for forming silk fabrics and knitted silk fabrics that can be used for general clothing. [Solution] The method for manufacturing silk processed yarn according to the present invention comprises a preparation step S1 of preparing two or more types of silk yarns with different degrees of shrinkage in response to salt shrinkage treatment; an entangled yarn generation step S2 of generating entangled yarns having entangled portions arranged at unequal intervals from the two or more types of silk yarns prepared; a salt shrinkage step S4 of applying salt shrinkage treatment to the generated entangled yarns; and a sericin fixing step S2 of fixing sericin contained in the two or more types of silk yarns before they become entangled yarns, or in the entangled yarns before they are subjected to salt shrinkage treatment.

Description

Technical Field

[0001] The present invention relates to a method for producing silk - processed yarns, and particularly to a method for producing silk - processed yarns suitable for forming silk woven fabrics and knitted fabrics that can be made into general clothing.

Background Art

[0002] Natural silk yarns are composed of amino acids of long fibers with a diameter of about 7 μm and a length of 1,000 - 3,000 m spun by silkworms. By removing hard sericin, which is one of the amino acids covering the outside of the yarn, a very thin, soft, and slippery silver - white yarn is obtained. Silk yarns have been highly valued as the "queen of fibers" since ancient times in product fields where aesthetic beauty and good touch are required. On the other hand, silk yarns are considered unsuitable for forming woven and knitted fabrics that can be made into general clothing. That is, it is considered difficult to form woven and knitted fabrics with a certain thickness and resistance to bending and rubbing using silk yarns.

[0003] Patent Document 1 describes a method for producing an entangled - type bulky - converged yarn that achieves both stretchability and bulkiness by making silk yarns into a tubular knitted shape including loop parts and then pulling out and converging the loop parts (i.e., unraveling the knitting). According to this converged yarn, it is considered that silk yarns can be utilized in a wider range of product fields than before.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above-mentioned bundled yarn did not meet requirements 1) and 4) of the requirements 1) to 4) required for yarn to form woven or knitted fabrics that can be used for general clothing. Note that stability in 4) means that the form and dimensions do not change during actual use. 1) It is lightweight despite having a relatively large diameter. 2) The surface has a moderate amount of protrusions. 3) It must be elastic. 4) Good stability

[0006] This invention has been made in view of these circumstances, and aims to provide a method for producing silk processed yarn suitable for forming silk woven and silk knitted fabrics that can be used as general clothing. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a method for manufacturing a silk processed yarn, which is a method for manufacturing a bulky silk processed yarn from long silk fibers, and is characterized by comprising: a preparation step of preparing two or more types of silk yarns with different degrees of shrinkage in response to salt shrinkage treatment; an entangled yarn generation step of generating an entangled yarn having a plurality of entangled portions aligned in the longitudinal direction from the two or more prepared types of silk yarns; a salt shrinkage step of applying salt shrinkage treatment to the generated entangled yarn; and a sericin fixing step of fixing sericin contained in the two or more types of silk yarns before they become entangled yarns, or in the entangled yarn before salt shrinkage treatment.

[0008] Examples of two or more types of silk threads prepared using the above manufacturing method include domesticated silk and wild silk.

[0009] Another example of the two or more types of silk yarn prepared by the above manufacturing method is domesticated silk yarn that has not undergone reaction inhibition treatment (a treatment that prevents tyrosine contained in domesticated silk yarn from reacting during salt shrinkage treatment) and domesticated silk yarn that has undergone reaction inhibition treatment.

[0010] An example of the salt shrinkage treatment in the above manufacturing method is a treatment in which the entangled yarn is immersed in an aqueous solution mainly composed of calcium nitrate at a predetermined concentration and temperature for a predetermined time. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for producing silk processed yarn suitable for forming silk woven and silk knitted fabrics that can be used as general clothing. [Brief explanation of the drawing]

[0012] [Figure 1] This is a flowchart showing a method for manufacturing silk processed yarn according to an embodiment of the present invention. [Figure 2] A schematic diagram showing the changes in entangled yarns during the salt shrinkage process, where (A) shows the entangled yarns before salt shrinkage treatment and (B) shows the entangled yarns after salt shrinkage treatment. [Figure 3] This is a flowchart showing a method for manufacturing silk processed yarn according to a modified example of the present invention. [Modes for carrying out the invention]

[0013] The following describes examples of the method for manufacturing silk processed yarn according to the present invention, with reference to the attached drawings.

[0014] [Examples] Figure 1 shows a flow chart of a method for manufacturing silk processed yarn according to an embodiment of the present invention. As shown in the figure, the manufacturing method according to this embodiment comprises a preparation step S1, a sericin fixing step S2 performed after step S1, an entangled yarn generation step S3 performed after step S2, and a salt shrinkage step S4 performed after step S3.

[0015] (Preparation process S1) In Step S1 of this project, two or more types of silk threads with different degrees of shrinkage for the salt shrinking treatment described later are prepared. In this example, a silk thread made by twisting three raw silk threads of about 27 denier and a tussah silk thread made by twisting three tussah silk threads of about 31 denier were prepared. The silk thread of the silkworm and the tussah silk thread differ in the content of tyrosine, which is one type of amino acid. The silk thread of the silkworm containing a large amount of tyrosine shrinks in the salt shrinking treatment described later. On the other hand, the tussah silk thread containing no (or only a little) tyrosine hardly shrinks in the salt shrinking treatment described later.

[0016] (Sericin Fixing Step S2) Sericin fixing refers to a chemical treatment that coagulates and keratinizes sericin to make it hardly soluble and adheres it to fibroin. In this Step S2, the sericin of the silk thread of the silkworm and the tussah silk thread prepared in the preparation Step S1 was fixed using a known sericin fixing method such as the formalin method, the synthetic resin method, or the chromium salt method. As a result, in the salt shrinking treatment described later, it is possible to suppress the movement of sericin on the surfaces of the silk thread of the silkworm and the tussah silk thread, resulting in a significant bias in the distribution of sericin, or the elution of sericin into the aqueous solution and random reattachment.

[0017] (Interlaced Thread Generation Step S3) In this Step S3, an interlaced thread is generated from the silk thread of the silkworm and the tussah silk thread that have undergone the sericin fixing Step S2. In this example, the silk thread of the silkworm and the tussah silk thread that have undergone the sericin fixing Step S2 were supplied to the processing machine described in Patent Document 1 (Japanese Patent Laid-Open No. 2018-165413) so as to be parallel to each other, and then made into a tubular knitted shape having a loop portion. After that, the loop portion was pulled out and converged (that is, the knitting was unraveled) to generate an interlaced thread.

[0018] As shown in Fig. 2(A), the interlaced thread has an interlaced portion that appears at a position corresponding to the loop portion. The interlaced portions appear with a certain degree of periodicity in the length direction of the interlaced thread, but do not appear at completely equal intervals. That is, in this Step S3, an interlaced thread having a plurality of interlaced portions arranged at unequal intervals in the length direction is generated.

[0019] As described above, in this embodiment, the processed silk yarn is obtained by supplying to the processing machine the silkworm silk formed by twisting three raw silk threads together and the wild silkworm silk formed by twisting three tussah silk threads together. Note that it is not preferable to supply the silkworm silk and the wild silkworm silk by twisting them together.

[0020] Note that it should be noted that Fig. 2(A) only schematically shows the structure of the entangled yarn generated in this step S3.

[0021] (Salt shrinking step S4) In this step S4, the entangled yarn is subjected to salt shrinking treatment. In this embodiment, the entangled yarn was immersed in an aqueous solution mainly composed of calcium nitrate heated to 91°C for 60 seconds and then thoroughly washed with water. The calcium nitrate aqueous solution was adjusted so that the specific gravity at 80°C was 1.40 by adjusting the amounts of water and calcium nitrate.

[0022] As described above, the silkworm silk constituting the entangled yarn has a greater degree of shrinkage in the salt shrinking treatment than the wild silkworm silk. Therefore, when the entangled yarn is subjected to salt shrinking treatment, as shown in Fig. 2(B), a yarn is obtained in which the shrunk silkworm silk is surrounded by the unshrunk wild silkworm silk. This yarn is the silk processed yarn obtained by the manufacturing method according to this embodiment.

[0023] Note that, similar to Fig. 2(A), it should be noted that Fig. 2(B) only schematically shows the structure of the silk processed yarn obtained in this step S4.

[0024] Since there is a large gap between the silkworm silk of the obtained silk processed yarn and the wild silkworm silk surrounding it, it has a sufficiently large diameter (that is, while being sufficiently bulky) and is lightweight. That is, the obtained silk processed yarn satisfies the above requirement 1).

[0025] For reference, Table 1 shows the measurement results of the weight and cross-sectional area of ​​the entangled yarn and the processed silk yarn. These results show that, after salt shrinkage treatment, the weight per meter of the entangled yarn increased by approximately 2.6 times (=0.54 / 0.21), and the cross-sectional area of ​​the entangled yarn increased by approximately 4.6 times (=6.25 / 1.36). In other words, these results show that the cross-sectional area increased by a much larger factor than the weight increase after salt shrinkage treatment. [Table 1]

[0026] The resulting processed silk yarn has moderate protrusions formed by the random bending of wild silk threads surrounding the domesticated silk threads. In other words, the resulting processed silk yarn satisfies requirement 2) above.

[0027] The resulting processed silk yarn loses a considerable degree of its inherent linearity because the wild silk fibers surrounding the domestic silk fibers are randomly bent. In other words, the resulting processed silk yarn satisfies requirement 3) above.

[0028] Furthermore, the resulting processed silk yarn has an entanglement section. In this entanglement section, the positional relationship between the domesticated silkworm filament located at the center of the processed yarn and the surrounding wild silkworm filaments remains almost unchanged. Therefore, in the resulting processed silk yarn, the wild silkworm filaments do not experience significant positional displacement relative to the domesticated silkworm filaments. In other words, the resulting processed silk yarn satisfies requirement 4) above.

[0029] [Differentiation] Although examples of the method for producing silk processed yarn according to the present invention have been described above, the configuration of the present invention is not limited thereto.

[0030] For example, the manufacturing method according to the present invention may include a sericin fixing step S2 that is performed after the entangled yarn generation step S3, rather than before, as shown in Figure 3. In this case, the sericin fixing step S2 is performed to fix the sericin of the entangled yarn (domestic silk and wild silk) obtained in the entangled yarn generation step S3 using a known sericin fixing method.

[0031] Furthermore, if the sericin fixing process S2 is not performed either before or after the entangled yarn generation process S3, in the salt shrinkage process S4, sericin may move across the surface of the domestic and wild silkworm filaments, resulting in an uneven distribution of sericin, or the sericin may dissolve in the calcium nitrate aqueous solution and randomly reattach to the domestic and wild silkworm filaments. As a result, the processed silk yarn will have a rough texture.

[0032] Furthermore, the two or more types of silk yarn prepared in preparation step S1 are not limited to a combination of domesticated silkworm yarn and wild silkworm yarn. For example, a combination of domesticated silkworm yarn that has not undergone reaction suppression treatment (a treatment to prevent tyrosine contained in domesticated silkworm yarn from reacting in the salt shrinkage treatment) and domesticated silkworm yarn that has undergone reaction suppression treatment may be used. In this case, in the salt shrinkage step S4, a processed silk yarn is obtained in which domesticated silkworm yarn that has not undergone reaction suppression treatment (shrunk domesticated silkworm yarn) is surrounded by domesticated silkworm yarn that has undergone reaction suppression treatment (domestic silkworm yarn that did not shrink).

[0033] Furthermore, the interlaced yarn generation step S3 may generate the interlaced yarn using a method other than the one described in Patent Document 1 (Japanese Patent Application Publication No. 2018-165413). For example, in the interlaced yarn generation step S3, the interlaced yarn may be generated using a known method for generating interlaced yarn using high-pressure air.

Claims

1. A method for producing bulky processed silk yarn from long silk fibers, A preparation process involves preparing two or more types of silk threads with different degrees of shrinkage in response to salt shrinkage treatment, A process for generating entangled yarns having multiple entangled portions arranged in the longitudinal direction from the two or more types of silk threads prepared, A salt shrinkage step in which the generated entangled yarn is subjected to the salt shrinkage treatment, A sericin fixing step for fixing sericin contained in the two or more silk threads before they are made into entangled threads, or the entangled threads before they are subjected to the salt shrinkage treatment, A method characterized by comprising:

2. Of the two or more types of silk threads mentioned above, one is domesticated silk and the other is wild silk. The method according to feature 1.

3. Of the two or more types of silk yarn, one is domestic silk that has not undergone reaction suppression treatment, and the other is domestic silk that has undergone the reaction suppression treatment. The reaction suppression treatment is a process to prevent tyrosine contained in the silkworm silk from reacting during the salt shrinkage treatment. The method according to feature 1.

4. The aforementioned salt shrinkage treatment is a process in which the entangled threads are immersed in an aqueous solution mainly composed of calcium nitrate at a predetermined concentration and temperature for a predetermined time. The method according to any one of claims 1 to 3, characterized by the features described herein.

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