JP2014031590A - Silk fiber product having modified surface and method for manufacturing the same - Google Patents

Abstract

The present invention provides a silk fiber product manufacturing method and a silk fiber product having an enhanced wrinkle recovery function without impairing excellent functional properties such as mechanical properties and dyeing properties of the silk fiber product.
A method for producing a surface-modified silk fiber product capable of enhancing the water absorption, hydrophilicity and wrinkle recovery function of the silk fiber product while preventing deterioration of the dyeability and mechanical properties. As the modification treatment, an ultraviolet irradiation treatment is performed in which the integrated light quantity is 700 to 7500 (mJ / cm ² ) and the ratio of oxygen to carbon O / C on the sample surface is 0.10 to 0.40.
[Selection figure] None

Description

    The present invention relates to a silk fiber product having enhanced dyeability, hydrophilicity and wrinkle recovery function, and a method for producing the same.

Silk fabrics are light and soft, durable, have excellent hygroscopicity, have excellent sensibility, and have a good texture, and have long been used as clothing materials. Recently, with the development of biotechnology, attention has been focused on the function of silk, a natural protein.
In addition, the protein constituting the silk is similar to the amino acid composition of the skin, so that it can be used as a biomaterial, which proves promising as a medical material such as a surgical suture for surgery.
As described above, the insect biopolymer silk fiber, which is a natural protein fiber, and its fiber product (sometimes abbreviated as silk fabric) have an excellent texture that is not found in synthetic fibers. Silk fiber products can be dyed in a deep color with various dyes in addition to the texture, and also have good moisture retention. Furthermore, it is important in considering the application of silk that the strength of the silk fiber has excellent mechanical properties that match the strength of the steel wire.

  On the other hand, silk fiber products have various characteristics that must be improved in the future in terms of wrinkle recovery, wrinkle resistance, washability, and light resistance. Because of these characteristics, silk fabrics have poor wrinkle recovery when wet, and there is a problem that they cannot be washed at home. For silk fiber products, for example, synthetic polyester polyester shuts can be worn as they are after drying without any wrinkles remaining after washing and drying on a hanger. These characteristics are wash and wear (W & W). Silk fiber products have low w & w properties, and silk fiber products have poor wrinkle recovery properties in wet and dry conditions, so silk fiber products have excellent wrinkle recovery properties due to chemical processing or physical processing. Development of technology for manufacturing is strongly desired.

Attempts to modify fibers other than silk fiber products have been made for a long time. Technical disclosure was made on the application of radiation graft polymerization to the modification of the practical performance of cellulosic fibers such as cotton and rayon. That is, a technique relating to a surface-modified fiber in which a ceramic material, a metal material, a fluororesin, and a silicone resin are attached to the surface of a synthetic fiber and a plant animal fiber by low-temperature plasma irradiation treatment has been disclosed (Patent Document 1). When this invention result is applied, a new function can be imparted to the fiber surface by the metal material, the fluororesin, and the silicone resin to be used while avoiding the characteristic deterioration of the material before the low-temperature plasma irradiation treatment.
When the fiber material is modified to a functional surface by this method, the metal material, fluororesin, and silicone resin are chemically attached to the fiber material by low-temperature plasma irradiation, and the surface is covered with a thin film. It has a feature that it does not peel even when a stimulus is applied.

As another method, a modified technique has been disclosed in which a vinyl compound is chemically grafted onto the material surface by γ-ray or electron beam irradiation to form a hydrophilic graft polymer film on the material surface (Patent Document 2).
Also, a method of graft polymerizing a fiber product by flowing a liquid containing a polymerizable vinyl monomer under contact with oxygen in a deoxygenated state (Patent Document 3), subjecting cellulose fibers to irradiation treatment, and polymerizing into fine pores of the fibers A technique (Patent Document 4) for improving durable W & W property and mechanical properties by filling a polymer of a monomer having a sexual double bond is disclosed.

As an attempt to modify the function of natural fibers by surface treatment, there is a study (Non-Patent Document 1) that clarifies the mechanical properties and shrinkage resistance of low-temperature plasma-treated wool fabrics. Regarding natural fiber silk fiber, a study that clarified changes in the water repellency and antifouling properties of silk fabrics by low-temperature plasma treatment using CF ₄ gas (non-patent paper 2), and a hydrophobic surface using a VUV excimer lamp. There are studies that have created a multifunctional silk fabric with a hydrophilic surface (Non-Patent Paper 3), and known research reports on XPS, SIMS, and ESR analysis of silk and wool irradiated with ultraviolet rays (Non-Patent Paper 4).

JP 2003-301371 A Japanese National Publication No. 9-506665 JP 2002-332321 A Japanese Patent Laid-Open No. 6-123074

Masakazu Mori, Mitsuo Matsudaira, Norihiro Higaki (2006); Mechanical properties and shrinkage resistance of low-temperature plasma-treated wool fabric, Journal of Textile Engineering, vol.52, No1.19-27. Okuno Atsuko and Sawa Yuko (1994); Changes in water repellency and antifouling properties of silk by low-temperature plasma treatment, Journal of the Japan Society of Home Economics, vol.45, 303-309. S.Periyasamy, M.L.Gulrajani, Deepti Gupta (2007); Preparation of a multifunctionalmulberry silk fabric having hydrophobic and hydrophilic surfaces using VUV excimer lamp, Surface & Coatings Technology, vol. 201, 7286-7291. Shao J, Carr CM, Rowlands CP, Walton J (1999); XPS, SIMS, and ESRStudies of UV / Ozone-irradiated Silk and Wool, J TextInst Part. 1, vol.90, No4, 459-468.

In recent years, silk protein (also referred to as silk protein) has excellent biochemical properties, so that applied research to regenerative medical materials such as artificial blood vessels and artificial skin materials has been remarkably developed. The prospect that silk protein can be used as various industrial materials has been opened, and in the future, application development is highly desired while evaluating new functions of silk protein. For this purpose, there is a great expectation for a technique for chemically modifying the surface of a textile product with various functions of the silk textile product.
In order to modify the surface of the textile product, in addition to conventional chemical processing, there is irradiation processing using energy rays such as radiation. Conventionally used techniques for modifying textile products are radiation, γ-ray irradiation, and low-temperature plasma treatment. These processes involve a problem that a large apparatus is required and equipment costs are required, an engineer who is proficient in handling the apparatus is required, and there is a problem that it is complicated to operate the apparatus.

There are several techniques that attempt to modify natural fibers, but far fewer than attempts to modify plastics, rubber, metals, and the like. When a silk fiber product is subjected to radiation treatment, mechanical properties are deteriorated or the product is colored and the practical performance of the fiber is deteriorated.
An object of this invention is to provide the manufacturing method and silk fiber product of a silk fiber product which can perform an effective modification | reformation process, without impairing the various functions with which a silk fiber product is equipped.

As a result of studies conducted by the present inventor to solve such problems, it is possible to modify the sample surface to be hydrophilic without degrading the original properties of the silk fiber product by irradiating the silk fiber product with ultraviolet rays. The present invention was completed by successfully producing a silk fiber product excellent in wrinkle recovery, which is an important clothing function.
In the present invention, surface modification of a silk fiber product is performed by irradiating with a low-pressure mercury lamp (sometimes abbreviated as an amalgam lamp in the name of the lamp manufacturer used) to solve the above-mentioned problems that have been a problem in the past. As a result, the desired results were obtained.
A low-pressure mercury lamp is a discharge lamp that uses arc discharge light emission in mercury vapor with a mercury vapor pressure of 100 Pa or less in a rod-shaped glass tube. Various lamps are commercialized from various manufacturers. In the present invention, as an example, an amalgam lamp (trade name, NIQ60 / 34XL, manufactured by Heraeus) can be preferably used. In the amalgam lamp, a rare gas such as Ar (argon) and mercury or its amalgam (alloy of mercury and other metals) are sealed in a rod-shaped glass tube. 185nm from mercury vapor in the arc tube,
It is characterized by strong radiation at 254 nm. The irradiation energy emitted from the arc tube is used for sterilization, cleaning of semiconductors and liquid crystals, surface treatment, resin curing, spectroscopic analysis, and the like.

Ultraviolet radiation that is shorter than visible light and longer than soft X-rays by electromagnetic waves emitted from the arc tube generates ozone in the atmosphere, enabling the surface modification of the desired silk fiber product. In the present invention, due to the action of ozone generated by the irradiation of ultraviolet radiation from the arc tube, the surface of the silk fiber product becomes smooth on the order of nano-size, the ratio of oxygen to carbon on the surface of the silk fiber product increases, and the surface becomes hydrophilic. Can be improved.
The present inventors have found for the first time that the silk fiber product can be provided with excellent wrinkle recovery property while suppressing mechanical deterioration of the silk fiber product even when the silk fiber product is irradiated with a low-pressure mercury lamp. I came to let you.

Unlike ozone generated by a corona discharge type ozonizer, ozone generated in the sample atmosphere by ultraviolet irradiation from a low-pressure mercury lamp is clean ozone that is harmless to the human body and has no nitrogen oxidizing power. It is a major technical feature of the present invention that the surface of the sample is made hydrophilic by the ozone, and as a result, wrinkle recovery, which is an important practical performance of silk fiber products, has been confirmed. First, the outline will be described.
The material surface by ultraviolet irradiation is a technology that has been used for practical use since around 1980. By using a low-pressure mercury lamp, it is possible to modify the surface of a textile product without using a special reagent. In the present invention, only an ultraviolet irradiation lamp is used, and there is no need to use any other special solvent or solution.

The sample surface can be modified by placing the sample at a certain distance from the low-pressure mercury lamp and irradiating it with ultraviolet rays.
The main wavelengths of ultraviolet rays generated from low-pressure mercury lamps are 185 nm and 254 nm, and ozone is generated in the sample environment by irradiating UV light with the main component at the wavelength of 254 nm to activate the sample surface. The ultraviolet irradiation method is characterized in that the sample surface can be modified by a dry process, not by a dry process in which a material surface is chemically modified using a reaction reagent.

The material surface modification technology by UV irradiation has been studied for more than 50 years, but it is considered difficult to put it to practical use from an industrial point of view, and there are various restrictions on its application at the practical level. There were few examples.
However, in the first half of the 1980s, as the technology to make liquid crystal display elements high-density and miniaturized progressed, the damage to the surface was small, so it was adopted as a cleaning technology for glass for liquid crystals, and now it is used to make liquid crystal products It has become an indispensable standard technology.
The reforming technology was a little behind the above-mentioned examples, and practical use began in the early 1990s. In other words, it has been adopted for pre-painting of passenger car mudguards and pre-painting of orbital coil moldings of magnetically levitated linear motor cars. In addition, it has been adopted to improve the adhesion of engineering plastics for passenger car engine devices and electronic equipment.

In the present invention, a surprising effect that the wrinkle recovery rate of the silk fiber product can be increased while preventing the deterioration of the quality of the silk fiber product by irradiating with ultraviolet rays has been recognized.
In order to enhance the wrinkle recovery property of the silk fiber product, the integrated light quantity on the sample is preferably controlled within a certain amount. The integrated light quantity corresponds to substantial irradiation of the sample by irradiation.
In order to specifically increase the wrinkle recovery rate while avoiding deterioration of various functions of silk fiber products due to ultraviolet irradiation, the cumulative amount of light that should be irradiated to the silk fiber products is 700-7500 (mJ / cm ² ), especially Desirably, it is 2000-4000 (mJ / cm < ² >). If the integrated light intensity is 700 (mJ / cm ² ) or less, the irradiation energy on the sample surface modification is too low, the surface modification effect becomes insufficient, the surface hydrophilicity cannot be enhanced, and the silk fiber product Water absorption, wrinkle recovery rate, and abrasion cannot be expressed. When the integrated light intensity exceeds 5000 (mJ / cm ² ), the UV irradiation energy on the sample surface is too high, and the unevenness of the sample surface changes on the order of nm. As a result, the water absorption and wrinkle recovery of silk fiber products On the contrary, the rate and wear resistance are reduced.

In the present invention, when the silk fiber product is irradiated with ultraviolet rays, the ratio N / C of nitrogen to carbon and the ratio O / C of oxygen to carbon on the sample surface increase when the sample becomes hydrophilic with the irradiation time. The value of N / C or O / C is determined by X-ray photoelectron spectroscopy (XPS) measurement that matches the ease of wetting of water droplets on the sample surface, that is, the hydrophilicity scale, and enables composition analysis of the sample.
In general, the amount of UV irradiation is controlled so that the properties such as strength / elongation, coloration, water absorption, and abrasion of the sample are not significantly degraded by the UV irradiation treatment compared to these properties of the unprocessed sample. However, it is preferable to increase the N / C and O / C values.

In the present invention, silk fiber products that are silk proteins made by silkworm, an animal protein, are targeted. However, other protein fibers such as wool keratin / wool and wool fabric products may be similarly targeted. it can. Furthermore, even proteins having different forms such as fibers, membranes, powders, and bulks are targeted.
In addition, a regenerated silk fibroin aqueous solution prepared by dissolving silk yarn with a neutral salt and dialysis treatment, a low molecular silk powder obtained by hydrolyzing silk yarn with an organic acid, and a silk membrane obtained by freezing and solidifying a regenerated silk fibroin aqueous solution Also, silk powder having a low molecular weight obtained by freeze-drying a regenerated silk fibroin aqueous solution can be used as well.

  According to the silk fiber product and the method for producing the same according to the present invention, since surface modification is possible by ultraviolet rays generated from a low-pressure mercury lamp, these conventional methods requiring large facilities such as radiation treatment and γ-ray irradiation treatment method. Compared to, the surface of the sample can be easily modified, and it is possible to effectively improve the low wrinkle recovery, which was a drawback of silk fiber products, and to broaden the use of silk fiber products in the clothing field. be able to.

It is a figure which shows schematic structure of an ultraviolet irradiation device. It is a photograph which shows the adhesion state of the water droplet on the silk fabric surface. It is the XPS spectrum of the silk fabric measured by changing the irradiation time of ultraviolet rays. It is a C1s spectrum of the silk fabric which changed the irradiation time of an ultraviolet-ray.

In Examples of the present invention, silkworm-derived silk fibers and silk fiber products were used as silkworm-derived silk proteins. However, the present invention is not limited to silk fibers and silk fiber products derived from rabbits, but derived from wild silkworms. Silk fiber and silk fiber products can also be used.
For example, as silk protein derived from a rabbit, a silkworm derived from a rabbit (Bombyx mori) bred by a farmer or a silkworm derived from a silkworm larva of a close relative of the rabbit (raw silk thread as silk fiber derived from a rabbit) can be used. In addition, silkworms derived from moths (Antheraea pernyi), Tenther (Antheraea yamamai), Tather shark (Antheraea militta), Muther moth (Antheraea assama), Eli moth, Shinju moth, castor moth larvae, etc. Can be used as silk fiber. Silk fibroin fibers obtained by scouring raw silk can also be used. Furthermore, silk fibers and silk fiber products derived from rabbits and wild silkworms, and fiber assemblies thereof can be used.

(1) Silk fabric Irradiating silk fabric derived from rabbits (14 匁 二 重 二 重, manufactured by Japan Standards Association, compliant with JIS L0803) for a specified period of time using an irradiation device with a low-pressure mercury lamp designed by the inventors. did. The ultraviolet treatment time was 1, 3, 5, 10, 15 minutes. After the irradiation treatment, experiments such as wettability evaluation, physical property evaluation, and structural analysis were performed.
The thicknesses of the warp and the weft constituting the silk fabric (double wing) were 2.3 tex X 3 and 2.3 tex X 4, respectively, and the density of the warp and the weft was 264,190 yarns / cm. here
2.3 tex X 3 means a twisted yarn in which three silk threads with a fiber thickness of 2.3 tex are aligned.

(2) Mechanical properties The high elongation of silk was measured according to the labeled strip method (JIS L1096). Approximately the same number of yarns were removed from both ends of the width of the sample cut to about 3 cm × about 20 cm to a width of 2.5 cm. The holding interval was 10 cm, the tensile speed was 100 mm / min, and the load cell was 5 N. A Tensilon tensile tester (Orientec Co., Ltd.) was used for the measurement. The sample pieces irradiated with different irradiation times with the low-pressure mercury lamp were measured 10 times for the strength and the elongation in the vertical direction and the horizontal direction. The average value or the strength (N) and elongation (%) of the total 20 measurements were obtained.

(3) SEM observation The surface of the grafted silk fiber product on which gold was vapor-deposited with an ion sputtering apparatus was observed with an SEM (scanning electron microscope) manufactured by Shimadzu Corporation.

(4) Wrinkle recovery test The wrinkle recovery rate, which is the practical performance of the textile product, was measured using a 7-line Monsanto Recovery Tester (manufactured by Daiei Kagaku Seiki Seisakusho) according to the Monsanto method (JIS L1059-1). Place a 500 g weight on the sample folded by the prescribed method for 5 minutes. After removing the load, the wrinkle recovery rate was determined from the opening angle after 5 minutes. Ten samples of silk fiber products each having a size of 15 × 40 mm were collected from the vertical direction and the horizontal direction for the samples with different irradiation treatment times, and the wrinkle recovery rate was measured 20 times in total, and the average was taken as the wrinkle recovery rate.

(5) Abrasion test Abrasion strength was measured using a universal abrasion tester (manufactured by Daiei Kagaku Seisaku Seisakusho) according to the universal geometry method (the plane method). The silk fiber product was placed on a rubber film attached to a flat wear table, rubbed in multiple directions with abrasive paper attached to a pressure plate, and the number of reciprocating tables until the sample broke was measured. Five samples each having a diameter of about 12 cm were collected for each treatment time, and the average of five measurements was taken as the friction strength.

(6) Irradiation device using a low-pressure mercury lamp An amalgam lamp (trade name, model NIQ60 / 34XL, manufactured by Heraeus), which is a low-pressure mercury lamp, is used as an ultraviolet irradiation source, and a sample cloth is placed at a certain distance. The irradiation treatment was performed for a certain time.
An irradiation apparatus using an amalgam lamp is shown in FIG. A support 20 for supporting the sample 10 to be irradiated with ultraviolet rays, and an ultraviolet irradiation lamp (in some cases, abbreviated as an amalgam lamp depending on the product name of the lamp used) disposed above the sample 10 in parallel with the longitudinal direction of the sample 10. Were irradiated with ultraviolet rays as a structure covered with a box-shaped case 40 made of stainless steel. Ventilation holes 42 were provided in the corners of the case 40 so that ozone did not stay excessively in the case 40.
The amalgam lamp is a lamp in which an amalgam, which is a special rare metal, is enclosed, and can increase the output by about 2 to 3 times compared to a conventional known low-pressure mercury lamp. The characteristics of the amalgam lamp used in the examples are summarized in Table 1 (Source: www.heraeus.co.jp/noblelight/)

In Table 1, the irradiation intensity means a value at a wavelength of 254 nm. Further, “approx” means a value of “approximately”.
The distance between the amalgam lamp and the sample was 20 mm, which is the limit of the effective irradiation distance of the amalgam lamp. The irradiation time was set to 1, 3, 5, 10, and 15 minutes.
As a result of measuring the irradiation intensity of C wave (wavelength 248nm-260nm) using ultraviolet intensity meter UVC-254 (made by Custom Co., Ltd.), it was 12.36mW / cm ² (30 times average) at an irradiation distance of 20mm. .

The integrated light amount accumulated in the sample placed under the amalgam lamp is obtained by the following equation (1) based on the values of the ultraviolet intensity and the irradiation time.
Integrated light quantity (mJ / cm ² ) = UV intensity (mW / cm ² ) x irradiation time (sec) (1)
Table 2 shows the accumulated light amount accumulated in the sample by the ultraviolet irradiation device used in the examples.

(Analysis of surface shape and surface chemical composition)
The shape analysis and surface chemical composition of the UV-irradiated sample surface can be analyzed by SPM and XPS, respectively.
More specifically, the change in the surface shape of the silk fiber due to the surface treatment can be considered by a scanning probe microscope (SPM) that analyzes minute irregularities on the sample surface while scanning the sample surface with a sharp probe. SPI3800 and SPA-400 multipurpose units were used for SPM measurement, and DFM mode was used as the measurement mode. The scanning area was 1 μm × 1 μm. In the SPM analysis, the silk fabric was disassembled to a single silk thread, fixed on double-sided tape, then processed and used in the experiment. Three silks were collected for each treatment time. Each of them was scanned at 5 locations, and a total of 15 images and measurement results were obtained.
The chemical composition of the silk surface by surface treatment can be evaluated by X-ray photoelectron spectroscopy (XPS).
XPS irradiates a solid sample placed in a high vacuum with a soft X-ray of over 1 keV, and measures the intensity and energy intensity of photoelectrons excited and emitted from the vicinity of the sample surface in the depth range of several nm. The elemental composition and chemical state can be clarified on the order of 0.1%. For the XPS measurement, AXIS-ULTRA OLD (manufactured by KRATOS) was used, and the experiment was performed under the conditions of an X-ray source of Mg, Anode HT of 15 kV, and Emission of 10 mA. For each treatment time, the broad spectrum was analyzed once and the C1s spectrum was analyzed five times.

(Water absorption evaluation)
The samples were evaluated for water absorption according to the Bayrec method (JIS L1907). The bottom end of the vertically suspended test piece was immersed in distilled water and allowed to stand for 10 minutes, and then the water absorption was evaluated by the height of the raised water (mm). For each treatment time, five test pieces each having a size of 200 × 25 mm were collected from the vertical direction and the horizontal direction, and the average of 10 test pieces was obtained as a result. The water absorption of the sample was determined by dissolving the dye Orange II, which is an acidic dye, in water and conducting a water absorption test, and evaluating the difference in how water rises between untreated and treated.
Furthermore, in order to verify the durability of the effect of improving water absorption by UV irradiation, the test specimens used were washed and dried, and then left in an environment at a temperature of 20 ± 2 ° C and humidity of 65 ± 2% for one week. The water absorption was evaluated again. This persistence verification was performed on test specimens after 1 week, 2 weeks, and 3 weeks after treatment.

(Evaluation of yellowing degree)
Evaluation of yellowing degree (JIS K7105) was performed using a spectrophotometer. Spectral reflectance was measured with a spectrophotometer to obtain tristimulus values X, Y, and Z values, and a difference ΔYI between the yellowing degree YI at each treatment time and the yellowing degree YI0 at the time of untreatment was obtained. From this ΔYI value, it is possible to evaluate the degree of coloring of the sample.

(Example 1) Improvement of wettability of silk fabric treated with ultraviolet irradiation
A silk fabric (silk feather double, manufactured by Tohoku Yarn Co., Ltd.) derived from a rabbit with 14 wrinkles was used. The sample was washed with distilled water at 60 ° C. for 5 minutes, dried and then irradiated using an ultraviolet irradiation device (FIG. 1). After the irradiation, the sample was left for 4 days in an environment of temperature 20 ± 2 ° C. and humidity 65 ± 2% and subjected to various experiments.
In order to examine the wettability of water droplets dripped onto the surface of the silk fabric treated with ultraviolet rays, 50 μl of water droplets were dripped onto the silk fabric with a glass micro-injection syringe, and the form of the water droplets was observed with a photograph. Fig. 2 shows a photographic image of the state of water droplet adhesion on the surface of a silk fabric when the irradiation time of ultraviolet rays is changed to 0 minutes (a), 1 minute (b), 3 minutes (c), and 15 minutes (d). Show.
The following can be seen from FIG. The wettability of the silk fabric surface was improved by the ultraviolet irradiation treatment, and the wettability of the silk fabric surface rapidly improved after the irradiation time of 3 minutes, and the sample surface became a hydrophilic surface.

As described in the above experiment, the contact angle of the water droplet on the sample surface was determined by a drawing method based on the photograph of water droplet adhesion on the surface of the silk fabric treated with ultraviolet irradiation. The obtained results are shown in Table 3.
Table 3 shows the following. It was confirmed that the wettability of the surface of the silk fabric was remarkably improved, and the contact angle of water was maximized and the sample surface was a hydrophilic surface in the irradiation time of 1 to 3 minutes.

(Example 2) Wettability of wild silk yarn by ultraviolet irradiation treatment The contact angle of the sample irradiated with ultraviolet rays on silk derived from silkworm (Antheraea pernyi) or Tenther (Antheraea yamamai) instead of the silkworm silk described in Example 1 is As in the case of the silkworm silk, the maximum was observed when the ultraviolet irradiation time was 1 minute, and there was a tendency to decrease compared to the unirradiated area when the irradiation time was 10 minutes or longer. The contact angles on the surface of the unirradiated silk fabric and the unirradiated tensil silk fabric are 54 and 53 °, respectively. However, when irradiated for 1 minute, the contact angles on the surface of the silk fabric and the tensil silk fabric are 65 and 64 respectively. It was a value that was specifically larger than the contact angle of the silkworm silk fabric.

(Example 3) Surface roughness analysis by scanning probe microscope (SPM) Silk fabric was subjected to ultraviolet irradiation treatment, and the relationship between the average roughness of the sample surface and the irradiation time was examined. The results obtained are summarized in Table 4.
In Table 4 and the following table, Unirradiated means silk fabric that has not been irradiated with ultraviolet rays.

The following can be seen from the SPM analysis results shown in Table 4.
It was found that there was a big difference in the surface shape of the silk fiber with the ultraviolet irradiation treatment. The planar roughness of the unirradiated silk fiber became smoother than that of the untreated silk fiber at the irradiation time of 1 minute. From this, it is known that the silk fiber has a groove-like structure running at an interval of about 0.2 μm, but it can be considered that the structure is destroyed by the surface treatment with the ultraviolet irradiation treatment. According to the scanning probe microscope (SPM) observation of the UV-irradiated sample, irregular aggregates began to appear after 3 minutes of irradiation time, and after 10 minutes of treatment, pits with a width of about 100 nm and a depth of about 60 nm appeared, 15 minutes In the treatment, the amount and size of pits increase, and the surface shape of the original silk fiber disappears.
As described above, according to the surface roughness analysis result, a decrease is observed during the 1 minute treatment, and it increases again at 3, 5, 10, and 15 minutes. In a short irradiation time, the surface is scraped and the roughness is reduced, but the groove-like structure disappears in the subsequent irradiation treatment.

(Example 4) Surface roughness of wild silk thread that can be evaluated with a scanning probe microscope (SPM) Wild silk silk was subjected to ultraviolet irradiation treatment, and the relationship between the average roughness of the wild silk thread surface and the irradiation time was examined in the same manner as in Example 3. It was. The silk thread from Antheraea pernyi or Antheraea yamamai was irradiated with ultraviolet light and observed with a scanning probe microscope (SPM). As with the silkworm silk described in Example 3, ultraviolet irradiation treatment was performed. The change of the surface roughness accompanying with was confirmed.

(Example 5) Chemical composition analysis using X-ray photoelectron spectroscopy (XPS)
X-ray photoelectron spectroscopy (XPS) is a type of photoelectron spectroscopy. By irradiating a sample surface with X-rays and measuring the energy of the generated photoelectrons, the type of constituent elements and oxidation state of the sample can be evaluated.
XPS analysis was performed on silk fabrics obtained by changing the irradiation time to 1, 3, 5, 10, and 15 minutes. The obtained broad spectrum is shown in FIG. Table 5 shows the detected sample composition and its concentration.

Table 5 confirmed the following. By comparing the XPS spectra of the unirradiated silk fabric and the UV irradiated sample, the composition change of the sample accompanying UV irradiation can be confirmed. The spectral intensity of O1s and N1s in the sample is increased by ultraviolet irradiation, and the abundance of O1s and N1s is increased on the silk sample surface. This means that the sample surface shows a decrease in carbon and an increase in nitrogen and oxygen due to UV irradiation. Hydrophobic chemical bonds and CO containing CH decrease on the sample surface during irradiation treatment, and C = O. It has been found that the abundance of hydrophilic chemical bonds containing sac is increased.
In addition, when comparing the composition ratio of carbon, nitrogen, and oxygen with respect to the silk fabric when untreated and treated, there was a decrease in carbon and an increase in nitrogen and oxygen due to treatment, the ratio of nitrogen to carbon N / C, The ratio of oxygen to carbon, O / C, tended to increase with increasing treatment time.
That is, it was confirmed that the silk fabric was made hydrophilic.

(Example 6) X-ray photoelectron spectroscopy (XPS) measurement results of wild silk irradiating with ultraviolet rays X-ray photoelectron spectroscopy (XPS) analysis was performed after irradiating ultraviolet rays to silkworm silk fabric derived from silkworm instead of rabbit silk yarn. . As in Example 5, when the silk fabric derived from silkworms was subjected to ultraviolet irradiation treatment, the irradiation time was 0, 1, 3, 5, 10, 15 minutes, the ratio of nitrogen to carbon N / C, the ratio of oxygen to carbon O / C was 0.10, 0.13, 0.19, 0.21, 0.27, 0.29 and 0.17, 0.27, 0.39, 0.31, 0.34, 0.35, respectively. Hydrophilicity of the surface of silkworm silk fabric by UV irradiation progressed more rapidly than that of silkworm silk fabric.
Next, the silkworm silk thread is dissolved in an aqueous 9 M LiSCN solution at 58 ° C., placed in a cellulosic dialysis membrane, dialyzed for 4 days, and a 2.2% silk silk fibroin aqueous solution is spread on the surface of the polyethylene membrane and evaporated. When the silk fibroin film was irradiated with ultraviolet rays, the O / C ratio of carbon to carbon was 0.20, 0.29, 0.40, 0.35, 0.37, and 0.39, respectively, with irradiation times of 0, 1, 3, 5, 10, and 15 minutes. The hydrophilization of silk silk fibroin membrane was significantly increased compared with silk silk fabric.

(Example 7) C1s spectrum by XPS FIG. 4 shows a C1s spectrum obtained by XPS analysis of an ultraviolet irradiation sample. However, the vertical axis unit arb.unit in FIG. 4 means an arbitrary intensity of the C1s spectrum.
As chemical bonding states of the C1s spectrum, the 285.0 eV peak is attributed to CH, the 286.6 eV peak to CO, the 287.9 eV peak to C = O, and the 289.1 eV peak to COO. From the comparison of spectra, Fig. 4 confirms the decrease in CH (285.0 eV) and the increase in C = O (287.9 eV) and COO (289.1 eV). It is confirmed that the introduced sample is hydrophilized.

Table 6 shows the results of determining the chemical bond ratio of the C1s spectrum by waveform separation of a sample obtained by irradiating the silkworm silk with ultraviolet rays.

Table 6 shows the following. When the time of irradiation treatment increases, hydrophobic chemical bonds including CH and CO decrease on the sample surface, and conversely, hydrophilic chemical bonds including C = O increase. In addition, COO generation was newly observed after 5 minutes of irradiation.
Furthermore, the increase in the C = O peak around 287.9 eV is considered to include the effect of the increase in the CO-N peak.

(Example 8) Tensile test using labeled strip method Tensile tests were conducted on silk fabric silk threads with different ultraviolet irradiation times by the labeled strip method. The results obtained are shown in Table 7.
Table 7 shows the following. The elongation and strength of the 15-minute sample irradiated with ultraviolet light were 22% and 21% lower than the elongation and strength of the untreated sample, respectively. It was found that the mechanical properties of silk fabric silk thread deteriorated when the ultraviolet irradiation treatment was excessive. However, when the ultraviolet irradiation time was about 3 minutes, the degree of mechanical property degradation was slight.

(Example 9) Evaluation of yellowing degree using a spectrophotometer It was measured using a spectrophotometer whether a silk fabric colored yellow with ultraviolet irradiation treatment. The yellowing degree (YI) was evaluated according to JIS K7105. The results of yellowing degree evaluation are shown in Table 8.
Table 8 shows the following. The YI of the untreated sample gradually increased with the ultraviolet irradiation treatment, and the ΔYI value of the silk fabric treated with the ultraviolet irradiation at the irradiation of 15 minutes became the maximum. This means that the yellowing degree of the silk fabric gradually progresses when irradiated with ultraviolet rays. When the irradiation time is about 3 minutes, the change in the value of ΔYI of the silk fabric is minute.

(Example 10) Transfer printing dyeing Changes in dyeing degree and color of silk fabrics that have been irradiated with ultraviolet rays dyed with blue disperse dyes by printing or transfer printing dyeing methods, and silk fabrics that have been dyed with Orange II It was investigated.
Transfer printing dyeing is performed by placing a transfer printing stamp on the surface of the sample cloth, sandwiching the front and back of the silk fabric with 50% cotton and 50% polyester, and adjusting the temperature to 160 ° C from the top of the pad (National) A method of heating for 4 minutes with a commercial steam iron NI-650P) was adopted.

(Dyeing with Orange II)
Dyeing experiments were conducted using Orange II as the dye. The dyeing conditions were a dye concentration of 3% owf, a bath ratio of 1:80, and a dye bath with acetic acid at pH 3. In addition to silk cloth, nylon as a control sample was simultaneously put in the dyeing bath and dyed. The dyeing bath temperature was raised from room temperature to 80 ° C. and then treated at the same temperature for 60 minutes. After 60 minutes, it was allowed to stand at room temperature, thoroughly washed with water, and allowed to dry naturally for one day.
(Colorimetric measurement)
A spectrophotometer (CONICA MINOLTA SPECTROPHOTOMETER, manufactured by Konica Minolta Co., Ltd.) was used to evaluate the K / S value corresponding to the surface dyeing density of the silk fabric subjected to transfer printing and the nylon fiber product used as a comparative example. The main absorption wave number of the dye used this time is 560 nm, and K / S corresponding to this wavelength was measured. The degree of staining of these samples was measured with a spectrocolorimeter. Each sample was measured three times, and the average value was obtained as the result.

Table 9 shows the K / S measurement results for transfer printing dyeing. Transfer textile dyeing was performed using a nylon fabric as a comparison sample of silk fabric and silk fabric. The obtained results are shown in Table 9 as comparative examples.
In Table 9, S-Tr and N-Tr mean silk fabrics and nylon fiber products used in transfer printing dyeing experiments.

Table 9 shows the following. In the transfer printing dyeing, K / S of the untreated silk fabric showed a low value, and it was confirmed that the untreated silk fabric was difficult to dye. When the ultraviolet irradiation treatment is about 5 minutes, it shows a value almost equal to the dyeing amount of the untreated silk fabric, but when the irradiation time is 15 minutes, the dyeing amount further decreases, but the irradiation time is about 5-10 minutes. In some cases, the K / S value of silk fabric irradiated with ultraviolet rays is not significantly different from the dyeing rate of untreated silk fabric.
Nylon (N-Tr) as a comparative example had an extremely good transfer printing dyeing amount even in an untreated sample, and the decrease in K / S value was slow when the ultraviolet irradiation time was within 5 minutes.

K / S values corresponding to the surface dyeing concentrations of silk fabrics dyed with Orange II and nylon fiber products used as comparative examples were determined. Table 10 shows the obtained results.
Table 10 shows the following. The K / S value of the dyed silk fabric is about 1/2 of the K / S value of the nylon fiber product. In both samples, the K / S values tended to be almost the same or slightly decreased as the UV irradiation time was increased.

(Example 11) Ultraviolet irradiation time, water absorbency of silk fabric, wrinkle recovery rate, abrasion resistance The water absorption, wrinkle recovery degree, and wear function change of the silk fabric irradiated with ultraviolet rays were examined. The obtained results are shown in Table 11.

Table 11 shows the following. The amount of water absorption of the sample with an irradiation time of 1 minute increases slightly compared to the value of the untreated sample, and tends to reach a maximum value after 5 minutes of irradiation time and then reach a constant value.
The wrinkle recovery rate gradually increased as the irradiation time increased, and reached the maximum value after 3 to 5 minutes of treatment time. After that, after 10 and 15 minutes of irradiation, the wrinkle recovery rate of the silk fabric began to decrease.
The wear function becomes a value similar to the wear characteristic of the untreated sample even when the irradiation time is increased.
A similar absorptive experiment was conducted to examine whether the water-absorbing effect of silk fabric irradiated with ultraviolet rays did not change after irradiation. The effect of ultraviolet irradiation did not change within one month after treatment, It was found that the irradiation effect lasted for a long time.

(Example 12)
The silk fabric derived from silkworm (Antheraea pernyi) or Tenther (Antheraea yamamai) was irradiated with ultraviolet rays and the wrinkle recovery rate of the irradiated sample was measured. According to the measurement results, it was confirmed that there was a tendency similar to the silkworm silk yarn described in Table 10. That is, the wrinkle recovery rate of silkworm and tengu silk fabrics reached its maximum at a treatment time of 3 to 5 minutes, and after that, when the irradiation time was 10 minutes and 15 minutes, the wrinkle recovery rate of silk fabrics tended to decrease slightly.

Summing up the experimental results of each of the above examples, when the silk fiber product is irradiated with an amalgam lamp that generates ultraviolet light having a main wavelength of 185 nm and 254 nm, the surface of the silk fiber product is hydrophilized and the hygroscopicity is improved. It was confirmed that wrinkle recovery, which is a drawback, can be enhanced while minimizing the decline in the practical performance of silk fiber products as clothing materials.
In detail, according to the tensile test, the mechanical strength of the silk fiber decreases as the irradiation time of ultraviolet rays increases. In the present invention, it was possible to confirm the remarkable effect that the wrinkle recoverability of the silk fiber product was maximized after 3 to 5 minutes of ultraviolet irradiation while preventing the deterioration of these characteristics as much as possible. That is, with regard to the wrinkle recovery property of silk, it is particularly noteworthy that the wrinkle recovery rate of the silk fiber product irradiated with ultraviolet rays for 5 minutes as in the present invention is increased by 20% compared to the untreated sample.

As shown in the Examples, when the silk fiber product is excessively irradiated with ultraviolet rays with an amalgam lamp, the mechanical strength of the silk fiber product is lowered, and the color tone of the sample is gradually changed to yellow. Occurs. According to the present invention, the wrinkle recovery property of the silk fabric can be improved while minimizing the negative influence that the function of the sample deteriorates due to ultraviolet irradiation. For that purpose, it is good to control the irradiation time of ultraviolet rays by the amalgam lamp and the integrated light quantity below a certain amount.
That is, it is desirable to irradiate the optimal irradiation time of a low-pressure mercury lamp (amalgam lamp) for 1 minute to 10 minutes, and at that time, the integrated light amount exerted on the sample is 700 to 7500 (mJ / cm ² ). Further preferable irradiation time and integrated light amount are 3 to 5 minutes 2000 to 4000 (mJ / cm ² ), respectively.
If the accumulated light intensity is 700 (mJ / cm ² ) or less when irradiated with ultraviolet rays, the surface of the silk fiber product becomes hydrophilic or the wrinkle recovery rate of the silk fiber product is not sufficiently enhanced. When it is 7500 (mJ / cm ² ) or more, the mechanical properties of the silk fiber product are significantly deteriorated, the color of the sample is changed to brown or yellow, and the texture of the silk fiber product is deteriorated.

The ratio of nitrogen to carbon N / C and the ratio of oxygen to carbon O / C on the sample surface can be evaluated in detail by X-ray photoelectron spectroscopy (XPS) measurement of silk fiber products irradiated with ultraviolet rays. When UV irradiation treatment is applied to silkworm silk fabric, the UV irradiation time is 0, 1, 3, 5, 10, 15 minutes, and the ratio of nitrogen to carbon in the sample is 0.15, 0.22, 0.37, 0.26, 0.32, 0.32. (Table 5).
On the other hand, the ratio O / C of oxygen to carbon of silkworm silk fabric irradiated with ultraviolet rays becomes 0.17, 0.27, 0.39, 0.31, 0.34, 0.35 when the irradiation time is 0, 1, 3, 5, 10, 15 minutes. The silk fibroin film was irradiated with ultraviolet rays and the irradiation time was 0, 1, 3, 5, 10, 15 minutes, and the oxygen to carbon ratio O / C was 0.20, 0.29, 0.40, 0.35, 0.37, 0.39, respectively. Then, the degree of hydrophilicity by ultraviolet irradiation increases in the order of rabbit silk fabric and silkworm silk fabric, and in the silkworm silk fabric and silkworm fibroin membrane, the latter is easily hydrophilized if the ultraviolet irradiation time is the same. Accordingly, the degree of hydrophilicity of the silk fiber product in the silk fiber product is more remarkable than that of the silkworm silk fabric in terms of the degree of hydrophilicity by ultraviolet irradiation. It is also affected by whether it is a rabbit fiber sample or a membrane sample.
As already mentioned, generally, the properties of silk fiber products such as strength / elongation, coloring degree, water absorption, and abrasion tend to be deteriorated by the ultraviolet irradiation treatment. By controlling the amount of UV irradiation while considering so as to suppress it, a remarkable effect appears that the wrinkle recovery rate, which is a practical function of the silk fiber product, is enhanced without greatly degrading the properties of the raw sample.

Depending on the application for which the silk fiber product is desired, the conditions for irradiating the silk fiber product with ultraviolet rays can be appropriately set to impart hydrophilicity and wrinkle recovery function.
In the above embodiment, a low-pressure mercury lamp was used as the ultraviolet light source. However, an ultraviolet light emitting tube having an irradiation energy equivalent to the above-described integrated light amount was used, and the ratio of oxygen to carbon in the ultraviolet irradiation sample was 0.10 to 0.40. The irradiation source is not limited to an amalgam lamp (trade name) as long as it can be irradiated with ultraviolet rays so that the irradiation energy is equivalent to the irradiation energy corresponding to the above conditions.
The low-pressure mercury lamp of the present invention has a great advantage that it is much easier to handle than the radiation treatment for modifying the sample surface, the gamma ray irradiation treatment, and the electron beam irradiation apparatus, and the equipment cost is not required.

The silk fiber product and silk film subjected to irradiation / modification treatment with ultraviolet rays according to the present invention can be used in the clothing field, and the silk film and silk powder can also be used as biomaterials in the medical field.
The surface modification treatment introduces oxygen atoms into the silk fiber product, resulting in hydrophilicity of the silk fiber product and improved compatibility with living tissue, so that artificial blood vessels, contact lenses, and pharmaceuticals are gradually released. It can be widely used as biomedical materials such as sustained release carriers, wound dressings, gels for intradermal injection, and materials for cell culture substrates.
In addition, since the living cells adhere well and the cells proliferate efficiently on the surface of the composite of the surface-modified silk fiber product in the present invention, the cell scaffolding material can be adjusted as desired by changing the degree of ultraviolet irradiation treatment. Therefore, it can be used for immobilized enzymes, medical materials, biological component separation carriers, immunoassays, and cell culture bed substrates.

Claims (6)

  Silk fiber product characterized by surface modification by ultraviolet irradiation.   The silk fiber product according to claim 1, wherein the silk fiber product is a silk fiber product derived from a rabbit or a barbarian. Addition of Claims The silk fiber product according to claim 1, wherein the silk fiber product is a silk fiber product derived from rabbit or wild silkworm, and the shape thereof is a fiber, a film, or a powder. 3. The silk fiber product according to claim 1, wherein an integrated light amount given to the silk fiber product by the irradiation of ultraviolet rays is 700 to 7500 (mJ / cm ² ).   The silk fiber product according to any one of claims 1 to 4, wherein a ratio O / C of oxygen to carbon in the silk fiber product is 0.10 to 0.40. A silk fiber product manufacturing method capable of enhancing water absorption, hydrophilicity and wrinkle recovery while preventing deterioration of dyeability and mechanical properties, and has an integrated light quantity of 700-7500 (mJ / cm2), a method for producing a silk fiber product, characterized by performing an ultraviolet irradiation treatment in which the value of the ratio of oxygen to carbon O / C on the sample surface is 0.10 to 0.40.