JP7749219B2 - Fibers, yarns and blended yarns, and textile structures - Google Patents

Description

The present invention relates to fibers, yarns, blended yarns, and fiber structures. More specifically, it relates to fibers containing vegetable silica.

Functional supports with silica attached have been proposed for some time.

For example, Patent Document 1 listed below describes "a supporter that is designed to be worn on a specific part of the body, and has a supporter body formed using a stretchable material, and characterized in that the supporter body contains or has attached thereto a powdered vegetable powder of vegetable black silica extracted from rice husks that have been burned at a high temperature exceeding 1000°C." As a specific configuration, it describes a configuration in which multiple circular pieces of vegetable powder are attached to the surface of the supporter body that comes into contact with the skin.
It also states, "According to this invention, it is possible to provide a supporter that can more effectively generate terahertz waves, which are electromagnetic waves that can be felt as warmth as far infrared rays."

Silica can be broadly divided into mineral-derived silica (mineral silica) and plant-derived silica (vegetable silica). Silica takes on various crystalline structures depending on temperature and pressure conditions, with mineral silica contained in minerals such as quartz being crystalline, and vegetable silica contained in plant materials such as unburned rice husks being amorphous.
Traditionally, mineral silica, which is the second most widely produced after feldspar, has been used as an industrial raw material. However, in recent years, plant-based silica has been attracting attention as an amorphous silica that is considered safe and compatible with humans.

Utility Model Registration No. 3210843 (Claim 1, Effect of the Invention, Paragraph 0013)

In the above-mentioned Patent Document 1, multiple circular pieces of plant-derived powder are attached to the surface of the supporter body that comes into contact with the skin, but with this configuration, the plant-derived powder (plant-derived silica) can fall off with repeated use or washing.

The present invention aims to solve the above-mentioned problems by providing fibers, yarns, blended yarns, and textile structures that are less likely to lose vegetable silica. It also aims to provide fibers, yarns, blended yarns, and textile structures that use such vegetable silica and are safe and have excellent heat storage properties.

To solve the above problems, a fiber containing finely powdered vegetable silica was developed. As mentioned above, vegetable silica is silica found in vegetable materials such as rice husks and rice straw, and the silica present in unburned vegetable materials is amorphous. Vegetable silica is found in large amounts in combustion products obtained by burning or pyrolyzing vegetable materials. In addition to vegetable silica, combustion products of such vegetable materials usually contain other components as impurities. Furthermore, because amorphous silica can be converted to crystalline by high-temperature heating, the term "vegetable silica" is intended to include both amorphous and crystalline silica derived from plants.

This fiber is resistant to plant-based silica shedding. Finely divided plant-based silica powder is kneaded into the polymer in the fiber.

Here, the vegetable silica can be amorphous silica in the form of fiber.

This fiber is highly safe. Amorphous silica is widely used as a food additive, health food, and drinking water, and has a proven track record of safety. For example, silica obtained by burning plant materials at low temperatures becomes amorphous silica.
Although silica has a Mohs hardness of 7, amorphous silica has a lower density than crystalline silica and tends to be easier to grind than crystalline silica. Therefore, by using amorphous silica, the grinding time can be shortened to some extent.

Fine powder of plant silica can also be made into fibers with an average particle size of 0.1 to 10 μm.

This fiber improves productivity. If the average particle size exceeds 10 μm, clogging of the spinning filter, thread breakage, etc., are likely to occur, and various problems such as thread breakage during the drawing process and wear of guides are likely to occur. On the other hand, if the average particle size is less than 0.1 μm, secondary aggregation is likely to occur.
The average particle size of the fine powder of vegetable silica is more preferably 0.15 to 5 μm, even more preferably 0.2 to 3 μm, and most preferably 0.2 to 1 μm.

It can also be made into fibers containing 0.5 to 15% by weight of finely powdered vegetable silica.

This fiber has excellent heat storage capacity and productivity (spinnability). By having a vegetable silica fine powder content of 0.5% by weight or more, excellent heat storage capacity can be achieved. Furthermore, by having a vegetable silica fine powder content of 15% by weight or less, thread breakage during spinning is less likely to occur, resulting in excellent productivity.

It can also be made into fibers containing fine carbon powder.

The inclusion of carbon in this fiber further improves its heat storage capacity. For example, if the combustion product (which contains a lot of plant silica) obtained by burning plant material contains carbon, this carbon can be incorporated into the fiber along with the plant silica.

Fibers can also be made containing 0.5 to 13.0 parts by weight of carbon fine powder per 100 parts by weight of vegetable silica fine powder.

This fiber has even improved heat storage capacity. The content of carbon fine powder in the vegetable silica fine powder is preferably 1 to 8% by weight, and more preferably 2 to 6% by weight.

The above problem can also be solved by a fiber containing amorphous silica fine powder and carbon fine powder, which contains 0.5 to 15 weight percent amorphous silica fine powder and 0.5 to 13.0 parts by weight of carbon fine powder per 100 parts by weight of amorphous silica fine powder.

The above problem can also be solved by fibers containing a fine powder of combustion products obtained by burning or pyrolyzing silica-containing plant materials such as rice husks, where the fine powder of combustion products contains 0.5 to 15% by weight of amorphous silica fine powder and 0.5 to 13.0 parts by weight of carbon fine powder per 100 parts by weight of the amorphous silica fine powder. The combustion products include combustion products obtained by burning silica-containing plant materials and pyrolyzed products obtained by pyrolyzing silica-containing plant materials.

The fibers may also be core-sheath composite fibers consisting of a core and a sheath, with vegetable silica fine powder contained only in the core.

This fiber contains fine vegetable silica powder only in the core, which makes it less likely to break during spinning and further improves productivity.

The above problem can also be solved by a yarn using any of the fibers described above, or a fiber structure using at least a portion of such yarn.

The above-mentioned problems can also be solved by a blended yarn obtained by blending any of the staple fibers described above with staple fibers that do not contain vegetable silica fine powder. In this case, the blended yarn can be made such that the staple fibers that do not contain vegetable silica fine powder are staple fibers that have a deodorizing function.
Furthermore, the above problem can also be solved by a blended yarn containing 10 to 30% by weight of short fibers of any of the fibers described above and 10 to 90% by weight of short fibers of fibers that do not contain vegetable silica fine powder.
In addition, the above-mentioned problems can also be solved by a fiber structure at least partly using any of the blended yarns described above.

The present invention can provide fibers, yarns, blended yarns, and textile structures that are resistant to shedding of vegetable silica. It can also provide fibers, yarns, blended yarns, and textile structures that are safe and have excellent heat storage properties and use such vegetable silica.

FIG. 1 is a diagram illustrating an example of an evaluation device for heat storage and heat retention properties.

The fibers, yarns, blended yarns, and textile structures will be described below by way of example.
It should be noted that the following embodiments and examples are merely illustrative of the present invention, and the present invention is not limited to the following specific embodiments and examples.

1. Fibers The fibers contain fine powder of vegetable silica. First, examples of vegetable silica will be described, and then examples of fibers containing fine powder of vegetable silica will be described.

[Plant-based silica]
As mentioned above, vegetable silica is silica originally contained in vegetable materials such as rice husks and rice straw. For example, rice husks are said to contain approximately 15 to 20% by weight of silica (SiO ₂ ). To extract vegetable silica from silica-containing vegetable materials such as rice husks and rice straw, the vegetable material can be burned or pyrolyzed, for example. The resulting burned vegetable material will contain a large amount of vegetable silica. The vegetable silica content in the burned vegetable material will vary depending on the combustion conditions, but will be, for example, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or 90% by weight or more.

The vegetable silica contained in the fibers is preferably amorphous silica. While the vegetable silica present in unfired vegetable materials is essentially amorphous, depending on the combustion temperature, it can crystallize, resulting in a high crystalline content. For example, due to the influence of alkali metals contained in minute amounts in rice husks, crystallization can progress at combustion temperatures above 800°C. Therefore, to prevent the crystallization of vegetable silica, it is usually necessary to keep the combustion temperature below approximately 700°C.

[carbon]
The fibers may contain fine carbon powder. The fine carbon powder is not particularly limited, and for example, commercially available fine graphite powder or graphite powder may be used.

However, the burned plant material usually contains unburned carbon along with silica, although this depends on the combustion conditions, etc. Therefore, the carbon contained in the burned plant material can be utilized.
From this viewpoint, it is preferable to burn the plant material under conditions such that the carbon content in the burned plant material is 0.5 to 13.0 parts by weight per 100 parts by weight of amorphous silica.
However, since the combustion of plant materials containing a relatively large amount of unburned carbon has a high impurity content and a low silica content, it has been avoided. Therefore, in order to increase the purity of plant silica, it has been conventionally burned at temperatures above 600°C to minimize the carbon remaining.

In order to increase the carbon content in burned plant material, it is preferable to burn the plant material at a relatively low temperature of 600°C or less, as opposed to conventional combustion temperatures. The plant material combustion temperature is more preferably 350 to 550°C, and most preferably 400 to 500°C.

Alternatively, plant-based materials can be thermally decomposed rather than burned. The thermal decomposition temperature of plant-based materials is preferably 600°C or lower. The thermal decomposition temperature of plant-based materials is more preferably 350 to 550°C, and most preferably 400 to 500°C. The thermal decomposition time of plant-based materials can be, for example, approximately 30 minutes to 1 hour, 2 to 10 hours, 10 to 24 hours, 1 to 2 days, 2 to 4 days, 4 to 8 days, or 8 to 10 days.

In addition to the carbon contained in burned plant materials, commercially available carbon powder can also be used.

[Fine powder]
The vegetable silica obtained by the above-mentioned method or the like is pulverized into a fine powder. Various methods can be used for pulverization. At this time, it is preferable to pulverize the vegetable silica fine powder so that the particle size of the fine powder becomes an average particle size (d50: cumulative 50% particle size) of 0.1 to 10 μm.
The fine powder of vegetable silica thus obtained is used to produce fibers containing a predetermined amount of the same.

Finely pulverizing the burned material of plant-based materials containing plant silica and carbon allows for the carbon to be simultaneously pulverized and the plant silica to be pulverized. In this case, the particle size of the fine carbon powder is typically smaller than that of the fine plant silica powder. It is preferable to pulverize the carbon powder so that the average particle size (d50: cumulative 50% particle size) is 0.05 to 10 μm. The finely pulverized burned material preferably contains 0.5 to 15% by weight of amorphous silica powder and 0.5 to 13.0 parts by weight of carbon powder per 100 parts by weight of amorphous silica powder.

[polymer]
The polymer constituting the fiber, i.e., the polymer into which the vegetable silica fine powder or the like is kneaded, is not particularly limited. In consideration of the spinnability during spinning and the physical properties of the yarn, polyethylene terephthalate, nylon 6, nylon 66, etc. are preferred. Furthermore, when the fiber cross section is to be a core-sheath type fiber consisting of a core component and a sheath component, for example, two types of polymers can be selected from the above, one of which can be the core component polymer and the other the sheath component polymer.

[Fibrosis]
The fine powder of vegetable silica or the like is added to the polymer. At this time, fine powder of combustion products obtained by burning or pyrolyzing vegetable materials (including fine powder of vegetable silica as well as fine powder of carbon or the like) can be added to the polymer.
In the case of core-sheath fibers, the vegetable silica fine powder or the like may be added to either the core polymer or the sheath polymer. It can also be added to both the core polymer and the sheath polymer. Furthermore, vegetable silica fine powder or the like can be added only to the core polymer, which is then covered with the sheath polymer, to form a so-called core-sheath fiber.

When using sheath-core fibers, the ratio (weight ratio) of sheath component to core component is preferably in the range of 4:1 to 1:4, more preferably 3:1 to 1:3, and most preferably 2:1 to 1:1. Furthermore, the core component does not need to be a single core within the fiber; it can be two or more cores. Furthermore, a portion of the core component may be exposed on the fiber surface, or the core component may be covered by the sheath component.

There are no particular limitations on the method for adding the fine powder of vegetable silica to the thermoplastic polymer, but from the viewpoint of uniform dispersion, a method of forming master chips using a twin-screw extruder is preferred.
The timing of adding the vegetable silica fine powder is not particularly limited. It can be added to the reaction system at the beginning of polymerization and directly spun. Alternatively, the vegetable silica fine powder can be kneaded into the molten polymer in a so-called post-addition method. Furthermore, a so-called masterbatch method can be used, in which master chips containing a high concentration of vegetable silica fine powder are used.

The amount of finely powdered vegetable silica added is preferably 0.5 to 15.0% by weight of the fiber, more preferably 0.5 to 10.0% by weight of the fiber, and even more preferably 0.5 to 5.0% by weight of the fiber.

In addition to the vegetable silica fine powder, the fiber of the present invention may also contain carbon fine powder, various stabilizers, pigments, dyes, inorganic additives, etc. It is preferable for the fiber to contain 0.5 to 13.0 parts by weight of carbon fine powder per 100 parts by weight of vegetable silica fine powder.

To produce fibers, the above materials can be used in the usual fiber manufacturing process. Fiber thicknesses in the range of 0.5 to 15 decitex are preferred.

The cross-sectional shape of the fibers is not particularly limited. In addition to round cross sections, they can also have polygonal cross sections such as triangular to hexagonal cross sections, T-shaped cross sections, or U-shaped cross sections.

2. Yarn and Blended Yarn The above fibers can be spun individually to form yarn, or can be cut into staple fibers and blended with other staple fibers to form blended yarn.

When shortening the above fibers, conventionally known methods can be used. The fiber length is preferably 25 to 150 mm, more preferably 35 to 100 mm, and most preferably 40 to 60 mm. For example, in the case of 3.3 dtex, the number of crimps is preferably 12 to 15 per inch, and the crimp rate is preferably approximately 10%.

The fibers that can be blended with the above-mentioned fibers containing vegetable silica fine powder are not particularly limited. Examples include fibers with deodorizing properties, aramid fibers, and hollow fibers.

There are no particular limitations on the fibers with deodorizing properties, as long as they have deodorizing properties. For example, deodorizing fibers made of a thermoplastic polymer containing a phosphate of a tetravalent metal, a hydroxide of a divalent metal, and a photocatalyst can be used. Specifically, for example, deodorizing fibers can be used that have a core-sheath composite structure consisting of a core and a sheath, where the core is made of a thermoplastic polymer with a melting point of 150°C or higher, the sheath is made of polybutylene terephthalate, and the sheath contains a phosphate of a tetravalent metal, a hydroxide of a divalent metal, a photocatalyst, and an antioxidant.

Examples of aramid fibers include meta-aramid fibers and para-aramid fibers. Of these, para-aramid fibers are preferred due to their excellent cut resistance and heat resistance. Examples of such para-aramid fibers include polyparaphenylene terephthalamide fiber (manufactured by DuPont-Toray Co., Ltd., product name: Kevlar (registered trademark)) and copolyparaphenylene-3,4'-diphenyl ether terephthalamide fiber (manufactured by Teijin Techno Products Co., Ltd., product name "Technora"). Of these fibers, polyparaphenylene terephthalamide (hereinafter sometimes referred to as PPTA) fiber is preferred, as it has particularly excellent cut resistance.

There are no particular limitations on hollow fibers, so long as they are hollow or can be hollowed. Examples of hollow fibers that can be used include composite short fibers with a water-insoluble thermoplastic polymer as the sea component and a water-soluble thermoplastic polymer as the island component. Specific examples include composite fibers with a thermoplastic polymer having an equilibrium moisture regain of 2% or less as the sea component and a water-soluble thermoplastic polyvinyl alcohol-based polymer as the island component. Such composite fibers can be hollowed out by treating them with water to dissolve and remove the water-soluble thermoplastic polyvinyl alcohol-based polymer from the composite fibers.

3. Fiber Structures The above-mentioned yarns and blended yarns can be processed into fabrics such as woven fabrics and knitted fabrics, or sewn together to form fiber structures (textile products).

Examples include fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics; pile fabrics such as pile woven fabrics and pile knitted fabrics; clothing and other body wear items made from these; interior goods; bedding; and food packaging materials. Specific examples include clothing and body wear items such as underwear, sweaters, jackets, pajamas, yukata, white coats, slacks, socks, gloves, stockings, aprons, masks, towels, handkerchiefs, supports, headbands, hats, shoe insoles, and interlinings; various carpets, curtains, wallpaper, shoji paper, sliding doors, fiber blinds, artificial plants, upholstery fabrics for chairs, tablecloths, electrical appliance covers, tatami mats, futon filling (batting, etc.), futon covers, sheets, blankets, futon covers, pillows, pillowcases, bed covers, bed filling, mats, sanitary materials, toilet seat covers, wiping cloths, and filters for air purifiers and air conditioners.

The present invention will now be described in detail using examples, but the present invention is not limited to these. Ratios and percentages in the examples are by weight.

[Example 1]
In this Example 1, we used combustion products (pyrolyzed products) obtained by thermally decomposing rice husks at temperatures below 500°C (300-500°C). Pyrolysis was carried out for several days. Although the vegetable silica A contained in this combustion product was amorphous, the silica content in the combustion product was relatively low at 86% by weight. On the other hand, the combustion product contained a relatively large amount of carbon (graphite).
The burned plant material was then pulverized to obtain a fine powder of plant silica A (mixed with fine powder of carbon, etc.) with an average particle size of 1 μm. The pulverized product was gray in color.

This vegetable silica fine powder was mixed with ethylene glycol at room temperature to a predetermined concentration and thoroughly stirred. Terephthalic acid was then added, adjusting the molar ratio of ethylene glycol to terephthalic acid to 1.2, to produce a slurry. This slurry was continuously fed to an esterification tank for esterification, yielding an esterified product with an esterification rate of 98%. Sb ₂ O ₃ was used as the polymerization catalyst. The polymer obtained was spun and drawn according to a known method to produce a multifilament yarn with an intrinsic viscosity [η] of 0.63 and 84 dtex (24 filaments). This multifilament yarn contained 3 wt % vegetable silica A fine powder and 3.5 wt % carbon fine powder per 100 wt % vegetable silica A fine powder.

Next, to evaluate the heat storage and heat retention properties, a knitted fabric with a basis weight of 200 g/ ^m2 was produced using the multifilament yarn and heat-set at 180°C for 1 minute to produce Sample C. As shown in Figure 1, Sample C was placed on a sample stage (made of polystyrene foam) with a thermocouple 15 positioned underneath it and fixed with a work holder (not shown). After that, the sample was irradiated with artificial sunlight (lamp 12: Iwasaki Electric Co., Ltd., Eye Lamp <Spot> PRS100V500W) and the sample temperature was measured after 15 minutes. The irradiation distance L was 50 cm and the room temperature was 20±2°C.

The heat storage and heat retention properties were evaluated by measuring the temperature difference (ΔT°C) between a knitted garment made of polyester fiber (sample R in Figure 1) and sample C made from the fiber of each example, to see how high the temperature was, and evaluating the results according to the following criteria. The positions of the samples (C and R in Figure 1) were swapped and the measurement was repeated twice, and the average of the data was used as the test result.
◎: Temperature difference 7℃ or more
○: Temperature difference of 5°C or more △: Temperature difference of 1°C or more but less than 5°C ×: Temperature difference of less than 1°C

The evaluation results are shown in Table 1. The knit of Example 1 had particularly excellent heat storage and heat retention properties.

[Example 2]
In this Example 2, the combustion product obtained by burning rice husks at a temperature of approximately 1000°C was used. This vegetable silica B was obtained by burning rice husks at a high temperature, but it was amorphous because alkali metal impurities were removed from the rice husks before burning, and the silica content in the combustion product was high at 99.2% by weight. Furthermore, because the combustion temperature was high, the carbon content in the combustion product was small.
The burned plant material was then pulverized to obtain a fine powder of plant silica B (mixed with a small amount of fine powder of carbon, etc.) with an average particle size of 1 μm. The color of the pulverized material obtained was generally white.

Using this vegetable silica B fine powder and other ingredients, a multifilament yarn was obtained using the same method as in Example 1. This multifilament yarn contained 3% by weight of vegetable silica B fine powder and 0.1 parts by weight of carbon fine powder per 100 parts by weight of vegetable silica B fine powder.

A knit was produced in the same manner as in Example 1, and the same tests and evaluations were carried out. The evaluation results are shown in Table 1. The knit of Example 2 had excellent heat storage properties, but was inferior to the knit of Example 1.

From the above, Example 1, which contains a higher proportion of carbon, has improved heat storage capacity compared to Example 2. The exact mechanism behind this improved heat storage capacity is unknown, but it is thought that the far-infrared radiation characteristics of silica (quartz stone) tend to attenuate significantly in the wavelength range of 5 μm or less, and that the inclusion of carbon raises this attenuation level, resulting in overall flat infrared radiation characteristics.

The present invention has been described above with reference to specific embodiments, but the present invention is not limited to the above embodiments, and various changes and modifications may be made by those skilled in the art without departing from the scope of the claims attached to this application.

For example, in the above embodiments and examples, the carbon contained in the burned matter (pyrolyzed matter) of plant material was pulverized and incorporated into the fibers, but this is not limited to this. For example, in the above Example 2, which has a low carbon content, commercially available carbon powder may be added. In this case, it is preferable to add commercially available carbon powder so that the total amount of carbon powder is 0.5 to 13.0 parts by weight per 100 parts by weight of amorphous silica powder.

1. Heat storage and heat retention evaluation device
11 Sample stage
12 Lamp
15 Thermocouple

C. Examples
R control

Claims (13)

A fiber containing a fine powder of vegetable silica,
The fiber is a core-sheath type composite fiber consisting of a core and a sheath,
Only the core contains fine powder of vegetable silica.
fiber.
The vegetable silica is amorphous silica.
The fiber of claim 1.
Plant silica fine powder is
The average particle size is 0.1 to 10 μm.
The fiber according to claim 1 or claim 2.
Contains 0.5 to 15% by weight of fine powder of vegetable silica.
The fiber according to any one of claims 1 to 3.
Contains fine powder of carbon,
The fiber according to any one of claims 1 to 4.
The carbon fine powder is contained in an amount of 0.5 to 13.0 parts by weight per 100 parts by weight of the vegetable silica fine powder.
The fiber according to any one of claims 1 to 5.
A fiber containing fine powder of amorphous silica and fine powder of carbon,
Contains 0.5 to 15% by weight of amorphous silica fine powder,
The fine powder of carbon is contained in an amount of 0.5 to 13.0 parts by weight per 100 parts by weight of the fine powder of amorphous silica ,
The fiber is a core-sheath type composite fiber consisting of a core and a sheath,
Only the core contains fine powder of vegetable silica.
fiber.
A yarn using the fiber according to any one of claims 1 to 7 .
A fiber structure at least partly using the yarn according to claim 8 .
Short fibers of the fiber according to any one of claims 1 to 7 ;
and short fibers of fibers that do not contain vegetable silica fine powder.
Blended yarn.
Short fibers that do not contain vegetable silica fine powder
It is a short fiber of a fiber having a deodorizing function,
The blended yarn of claim 10 .
10 to 30% by weight of short fibers of the fiber according to any one of claims 1 to 7 ;
The fiber contains 10 to 90% by weight of short fibers that do not contain vegetable silica fine powder.
Blended yarn.
A fiber structure at least partly using the blended yarn according to any one of claims 10 to 12 .