JP2008029890A - Bath towel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide environment-friendly bath towels stable in quality and supply, having feeling like silk when rubbing the towel together and good feeling when used, which can be decomposed in comparatively short time in soil, activated sludge or compost for disposal, or which can be incinerated by generating no poisonous gas, and which generates combustion heat as low as that of cellulose for inhibiting generation of harmful NO<SB>X</SB>or SO<SB>X</SB>as much as possible. <P>SOLUTION: The bath towel is formed by using at least 50 wt.% of polylactic fiber having an optical purity of 90% or higher for warp and weft, and the weft is composed of crimped yarn. Alternatively, the bath towel is formed by using at least 50 wt.% of the polylactic fiber having an optical purity of 90% or higher for the warp and the weft, and 30% or more of the polylactic fiber is a modified cross-section fiber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bath towel that is excellent in biodegradability using polylactic acid fibers.

  Traditionally, natural towels such as cotton, hemp and silk have been used for bath towels. In recent years, synthetic fiber products such as nylon, polypropylene, and vinylidene chloride have been developed.

  Conventional towels made of natural fibers such as cotton, hemp, silk, etc. have poor durability and become hard to use for a long period of time, become dark or yellowish, and have mold during use. It may occur, or the strength may be easily reduced and the tear may occur, resulting in poor practical usability. On the other hand, towels made of synthetic fibers such as nylon, polypropylene, and vinylidene chloride have improved durability, but have a poor feeling of use, and have inherent problems such as changes in quality such as yellowing and darkening. In particular, the stiff hardness of synthetic fibers can cause irritation to the skin and can cause skin disorders such as black skin disease. Furthermore, the environmental impact of waste materials that have been attracting attention in recent years cannot be ignored.

Bath towels made of synthetic fibers are much cheaper and cheaper than those using natural fibers in terms of cost and supply, but stable supply is possible. There are difficulties not found in conventional natural fibers, such as not permanently degrading. In other words, it does not decompose in normal disposal, but remains in its shape semipermanently. Also, when it is incinerated, it generates a large amount of combustion heat, damages the incinerator, and NO _x , SO in exhaust gas. The amount of _X may be increased, or carcinogenic dioxins may be generated.

The present invention has stable quality and supply stability, has a squeaky feeling and excellent usability, and can be decomposed in a relatively short period of time in soil, activated sludge, or compost when discarded. Alternatively, an object of the present invention is to provide an environmentally friendly bath towel that does not generate toxic gas during incineration and can suppress the generation amount of NO _X and SO _X that are harmful due to the low combustion heat of cellulose.

The bath towel of the present invention has the following constitution (1) or (2).
(1) A bath towel characterized in that at least 50% by weight of polylactic acid fiber having an optical purity of 90% or more is used for each of the warp and the weft, and the weft is a crimped yarn.
(2) A bath towel characterized in that at least 50% by weight of polylactic acid fibers having an optical purity of 90% or more are used for each of the warp and the weft, and 30% or more of the polylactic acid fibers are irregular cross-section fibers.

In addition, the bath towel of the present invention preferably has the following configuration (3) or (4) as a more specific configuration.
(3) The bath towel according to the above (1) or (2), wherein the polylactic acid fiber used for the warp is a polylactic acid monofilament of 20 to 100d.
(4) The bath towel according to (1) or (2), wherein a polylactic acid processed yarn of 75 to 500d is used for at least a part of the polylactic acid fiber used for the weft.

  In the present invention, the bath towel refers to a towel used mainly for scouring in a bathroom.

The bath towel made of the polylactic acid fiber of the present invention has excellent usability and is decomposed by landfill treatment in the disposal process after use, and finally decomposes into water and carbon dioxide gas. Without causing excessive heat generation at the time of incineration, NO X effects on incinerators and combustion _gas, it is possible to reduce the generation amount of hazardous gases such as SO _X, it can be said that the friendly washcloths very environment . In addition, the bath towel made of polylactic acid fiber is a product that is both environmentally and healthily preferred, such as being slightly hydrolyzed and weakly acidic, and can create a skin-friendly situation.

  It is important that the optical purity (hereinafter abbreviated as OP) of the polylactic acid used in the present invention is usually 90% or more, preferably 94% or more, more preferably 96% or more, and particularly preferably 98. % Or more.

  If the OP does not reach 90%, the polymer crystallinity is low and the crystallization rate is low, so yarn breakage is likely to occur during fiber production, and the operability and the crystallinity of the resulting fiber are also reduced. In addition, there are problems in the manufacturing process and problems during use, such as low fiber strength, lack of thermal stability, and changes in dyeability. In addition, the heat-setting property when making crimped yarns by the knit / denit method, which is essential for the production of toweling fabric, is poor, and good crimp yarns cannot be produced, or bulky yarns such as wooly processed yarns cannot be produced. There are problems such as. When the OP is 90% or more, the crystallinity is good and the above problems are few. In particular, when the OP is 98% or more, the fiber crystallinity is particularly excellent, there are few problems during fiber production, and the strength and heat resistance of the obtained fiber and the setting property in knit / denit are extremely good.

  In general, polylactic acid is a polymer (a copolymer in a broad sense) in which L-form and D-form lactic acid that are optical isomers are mixed, and the optical purity of polylactic acid is determined by the ratio thereof. The body of living organisms in the natural world is almost composed of L-form compounds, and thus there are abundant enzymes that decompose polymers and compounds composed of L-forms. However, the D-form hardly exists in nature, and polymers and compounds containing a large amount of D-form are not easily decomposed in nature. Therefore, the polylactic acid fiber of the present invention is preferably poly L-lactic acid having a high L-lactic acid content.

  Therefore, in the composition of polylactic acid fiber, biodegradability decreases as the ratio of D-form increases. In that sense, OP is preferably higher.

  Polylactic acid fibers are produced by melt spinning or solution spinning of polylactic acid, and are preferred in that melt spinning has a small impact on production efficiency, product diversity, and production environment.

  In melt spinning, polylactic acid resin is heated and melted to a melting point or higher, and discharged and cooled in the air from a spinneret having minute holes to obtain fibers. The discharged / cooled fiber is wound to go to the next step. However, in the case of long fibers, the winding speed is called a conventional spinning method called POY (Partially Oriented Yarn). ) Method with a winding speed of about 5500 m / min or less, called a HOY (Highly Oriented Yarn) method, or a method with a winding speed of about 5500 m / min or more, or SPD (Spin) The (Draw) method can be employed. Further, since the short fiber is pushed out from a large number of nozzles as compared with the long fiber, the winding speed is usually slower than that of the long fiber, and it is usually performed at 2000 m / min or less. In particular, it is most commonly performed at 1500 m / min or less.

  In the bath towel of the present invention, it is important to use at least 50% by weight of polylactic acid fiber for each of the warp and weft of the fabric. The other fiber component of the bath towel (hereinafter abbreviated as “non-polylactic acid fiber component”) may be a conventional synthetic fiber or a natural fiber. Preferably, the majority of the non-polylactic acid fiber components are natural fibers, more preferably 2/3 or more are natural fibers, and particularly preferably all are natural fibers. When the polylactic acid fiber is less than 50% of the bath towel, there is no improvement in durability and feeling of use, or the biodegradability is poor.

  The polylactic acid fibers used in the present invention include non-circular cross-section fibers such as ordinary ○ (round) cross-section fibers, flat cross-section fibers, Δ (triangle) cross-section fibers, hollow cross-section fibers (◯, Δ), U-shaped cross-section fibers, etc. Any fiber cross section can be used. Considering the feeling of use and the like, it is possible to use a mixture of flat cross-section fibers, Δ (triangle) cross-section fibers, U-section cross-section fibers and the like rather than simple ○ (round) cross-section fibers. In order to improve the texture, swelling feeling, detergency, foaming properties, etc., it is to mix the deformed cross-section fibers in a weight ratio of about 10% or more, preferably 20% or more, more preferably 30% or more. In the case of mixing, in the case of filament yarn, a mixed yarn method may be used, but it may be used as a warp or weft of a woven fabric or a part thereof.

  The thickness of the polylactic acid fiber is usually 15 to 150 d monofilament or single yarn denier 2 to 30 d multifilament, preferably 20 to 100 d monofilament or single yarn denier 3 to 25 d multifilament, and more preferably 25. -75d monofilament or single yarn denier 4-20d multifilament. Whether to use a monofilament or a multifilament can be determined according to the application and target performance. In the multifilament, untwisted yarn, sweet twisted yarn or medium twisted yarn can be used, but it is preferable to use untwisted yarn in terms of cost.

  The polylactic acid fiber used for the weft of the bath towel of the present invention is usually a multifilament of 50 to 700d, preferably a multifilament of 75 to 500d, more preferably a multifilament of 100 to 400d. The single yarn (single fiber) denier is usually 3 to 15 d, but can be used depending on the purpose and application outside this range.

  Since the weft has an important role in the cleaning effect and the touch of the towel, the knit / denit method crimped yarn, the staffin method crimped yarn, the gear method crimped yarn, or the Panlon method crimped It is preferable to use machine-crimped yarn such as yarn, spiral-shaped crimped yarn by side-by-side composite yarn, or processed yarn such as false-twisted yarn. Particularly preferred are crimped yarns or knitted / denited yarns. One type of fiber may be used, and several types of fibers may be mixed and used for improving the texture, feeling of use, and durability. In particular, in the case of mixed use of fibers having a thick fineness and fibers having a fine fineness, the feeling of use and the durability are improved. In the combination of these fibers, the yarn itself becomes swollen by changing the difference in fineness and the shrinkage rate (for example, heat shrinkage rate) of each fiber, and the fluffy texture and soft feeling of use Is more preferable. In particular, when the shrinkage rate of the fine yarn is large and the shrinkage rate of the fine yarn is set low, this effect can be exhibited more remarkably.

  When using polylactic acid short fibers, not only spun yarn of 100% polylactic acid fibers, but also other fibers such as cotton, hemp, silk and other natural fibers, nylon, polyester and acrylic fibers should be used. You can also. However, from the viewpoint of environmental impact, it is preferable to use natural fibers as the blended partner. In addition, a richer texture, feeling of use, durability, etc. can be expressed by mixing and using polylactic acid staple fibers (short fibers) having different fineness and fibers having different hot water shrinkage rates. .

  In the bath towel of the present invention, in the case of short fibers, polylactic acid fibers or blended yarns of polylactic acid fibers and other fibers can be used as described above. Furthermore, among these fibers, other synthetic fibers or Natural fibers can be woven to develop a weaving pattern or dyeing.

  The texture of the woven fabric is not particularly limited as long as it is usually a woven texture used for toweling. For example, ordinary plain weave, twill weave, and satin weave are basically used, and those having a changed structure can also be used. Moreover, although it is usually a single woven fabric, a double woven fabric is also possible to give a high-class feeling. In particular, in the case of interweaving with other fibers, it is also preferable to use a structure other than plain weave in order to change the type of yarn to be put on the surface according to the characteristics of the fibers. For example, when a softer fiber is used for the weft and a softer texture is given, it is preferable to have a structure in which a large amount of weft is produced by twill weave or satin weave.

  The density of the woven fabric is usually 3 to 50 warps / inch, preferably 5 to 40 strands / inch, and more preferably 10 to 30 strands / inch. The weft is usually 15 to 50 yarns / inch, preferably 18 to 45 yarns / inch, and more preferably 20 to 40 yarns / inch.

  With 100% polylactic acid fiber, dyeing can be performed with a disperse dye at a temperature of 95 to 120 ° C., but polylactic acid fiber has a slightly lower dyeing fastness than conventional polyester fiber. However, the dye fastness can be maintained by appropriately selecting the dye. For example, those having medium hardness (SF to F type) are preferable. The dyeing concentration can be appropriately selected depending on the use and purpose. In the case of a bath towel used in combination with or mixed with other fibers, the other fibers can be dyed by two-bath dyeing or by one-bath dyeing in which other fiber dyes are simultaneously added. It is also possible to process ultraviolet absorbers, slip agents, antibacterial agents, etc. during or after dyeing. In particular, in order to improve light fastness, it is preferable to use an ultraviolet absorber of 1% / owf or more.

The bath towel of the present invention is excellent in biodegradability when discarded after use, and in the case of incineration, the combustion heat is 3400-3500 cal / g, which is the same as that of newspaper, so the furnace is damaged or NO. It can be easily incinerated without generating toxic gases such as _X and SO _X and dioxins.

  Furthermore, since the bath towel of the present invention is biodegradable, it can be buried in a corner of a home garden, treated with a home composting machine, or easily composted in a local compost factory. In this respect, the bath towel of the present invention can be said to be a very environmentally friendly material.

  Hereinafter, the present invention will be described specifically by way of examples. In the examples, “part” means “part by weight” unless otherwise specified, and “%” means “% by weight” unless otherwise specified.

  The relative viscosity ηrel was determined by a conventional method at 20 ° C. in a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio). Moreover, melting | fusing point (Tm) was calculated | required from the peak value of the endothermic peak of the differential scanning calorimeter (henceforth DSC) made from a Rigaku Corporation.

Example 1
A polylactic acid having an L-lactic acid content of 99.2%, ηrel = 3.1, a weight average molecular weight of 130,000, a melting point of 175 ° C. was melted at a melting temperature of 230 ° C., a pore diameter of 0.25 mm, and the number of pores It was extruded into the air from a spinning nozzle having 48 pieces and spun by a normal filament method to obtain a 75d / 24f bifilament filament. Similarly, a single filament was used to obtain a filament of 400d / 48f. Each strength 4.5g / d, 4.2g / d, elongation 34%, 37%, had physical properties of elastic modulus ^{685kg / mm 2, 645kg / mm} 2. The 75d / 24f yarn is used as a warp with a torque of 300 T / m. The 400d / 48f yarn is used as a weft yarn by crimping a tubular knitted fabric after heat treatment at 110 ° C. for 40 minutes and then knitting. Using the fibers, weft weft fabrics were manufactured with warp yarns appearing on the surface with a warp: 10 / inch and weft: 35 yarn / inch yarn design. The performance of the fabric as a bath towel was very soft against friction with the skin and good soap foaming. Moreover, the drainability after use was also good, and it was able to dry sufficiently indoors.

Example 2
A polylactic acid having an L-lactic acid content of 99.1%, ηrel = 3.3, a weight average molecular weight of 150,000, and a melting point of 173 ° C. was melted at a melting temperature of 235 ° C. It was extruded into the air from a spinning nozzle having 12 pieces and spun by a normal filament system to obtain a 30d / 1f monofilament for 12-minute fiber separation. A filament of 400 d / 24 f was obtained in the same manner as in Example 1. Each strength 4.0g / d, 4.3g / d, elongation 38%, 36%, had physical properties of elastic modulus ^{617kg / mm 2, 640kg / mm} 2. The 30d / 1f monofilament is used as it is as a warp. 400d / 24f is a woolen processed yarn (false twisted crimped yarn) obtained by putting a false twist of about 1500 T / m with a spindle type false twister, one of ten wefts of Example 1. Use instead of. Using this fiber (yarn), a plain woven fabric was produced with a design of warp: 10 / inch and weft: 35 / inch.

  The performance of the fabric as a bath towel was very soft, excellent in lightness, and very soft against the skin. The soap foaming was also good. Moreover, the drainability after use was also good, and it was able to dry sufficiently indoors.

Example 3
150d melted at 225 ° C. using the polylactic acid of Example 1 and extruded into the air from 96 pairs of nozzles consisting of 5 small holes with a hole diameter of 0.12 mm. / 96f (single fiber 1.56d) filament yarn was obtained. The fiber had physical properties of a strength of 4.5 g / d, an elongation of 35%, and an elastic modulus of 658 kg / mm ² . Two filament yarns were combined and false twisted with a spindle type false twister. This false twisted crimped yarn and the 400d / 24f knit / denit yarn of Example 2 are used as wefts in a ratio of 2/8.

  Moreover, 30d / 1f of Example 2 is used as a warp. As the warp, a plain woven fabric was manufactured with a design of 10 yarns / inch alternately of 300d / 192f processed yarn and 400d / 24f knitted / denit yarn and 30 weft / inch yarn. The performance of the fabric as a bath towel was very soft, excellent in lightness, and very soft against the skin. The soap foaming was also good. Moreover, the drainability after use was also good, and it was able to dry sufficiently indoors.

Claims (4)

  A bath towel characterized in that at least 50% by weight of polylactic acid fiber having an optical purity of 90% or more is used for each of the warp and the weft, and the weft is a crimped yarn.   A bath towel characterized in that at least 50% by weight of polylactic acid fibers having an optical purity of 90% or more are used for each of the warp and the weft, and 30% or more of the polylactic acid fibers are irregular cross-section fibers.   The bath towel according to claim 1 or 2, wherein the polylactic acid fiber used for the warp is a polylactic acid monofilament of 20 to 100d.   The bath towel according to claim 1 or 2, wherein a polylactic acid processed yarn of 75 to 500d is used for at least a part of the polylactic acid fiber used for the weft.