JP2010100950A - Polylactic acid monofilament and woven fabric using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid monofilament solving the problems of deformation of a sash for a screen door and runout of the sash for the net door using a woven fabric at preservation, transportation and practical use after application to the sash or the like for the screen door, and to provide a woven fabric for the screen door. <P>SOLUTION: The polylactic acid monofilament using a polylactic acid resin has 0-0.04 cN/dtex heat shrinkage stress at 80°C, and 0.5-1.3 cN/dtex stress at the primary yield point. The woven fabric for the screen door is obtained by using the polylactic acid monofilament at least as parts of warp yarns and/or weft yarns, and has 10-40 yarns/in densities of the warp yarns and the weft yarn. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polylactic acid monofilament, and more particularly, a polylactic acid monofilament having a small dimensional change due to a use environment and a storage environment even when stretched on a fixed length frame such as a screen sash, and the monofilament. It relates to textiles.

  Polylactic acid resin is a carbon neutral material obtained from non-petroleum-based raw materials, and because it is biodegradable, it has recently attracted attention as a material that has a low environmental impact and does not increase the amount of waste. Product development using is actively promoted in each industry.

  In the fiber field, various fibers such as multifilaments, monofilaments, slit yarns, crimped yarns, staple fibers, and nonwoven fabrics are being developed for practical use.

  Patent Document 1 also discloses a technique for applying polylactic acid monofilaments to screen door fabrics, which are the technical field of the present invention, and Patent Document 2 also discloses polylactic acid monofilaments that can be used as screen door fabrics. It is disclosed in Patent Document 3 and the like. However, at present, polylactic acid monofilament has not been put into practical use as a screen door fabric.

One of the reasons why polylactic acid monofilaments are not put into practical use as screen door fabrics is their shrinkage properties. When screen door fabrics made of conventional polylactic acid monofilaments are applied to screen door sashes, they are stored, used, and transported. In other words, there are problems that the screen door fabric is detached from the sash, and that the sash is deformed even when it is not detached from the sash.
JP 2002-54375 A JP 2000-27030 A Japanese Patent Laying-Open No. 2005-307428

  The present invention provides a polylactic acid monofilament that solves the problem of deformation of a screen door sash during storage, transportation, and actual use after being applied to a screen door sash, etc., and a fabric for screen doors. This is the issue.

  As a result of repeated studies by the present inventors, a polylactic acid monofilament using a polylactic acid resin having a heat shrinkage stress at 80 ° C. of 0 to 0.04 cN / dtex and a primary yield point stress of 0.5 to The inventors have found that a polylactic acid monofilament of 1.3 cN / dtex can solve the above-mentioned problems, and have reached the present invention. The polylactic acid monofilament of the present invention preferably has a boiling yield of 0 to 5% and an elongation of 25 to 70%.

  Further, a fabric using the polylactic acid monofilament of the present invention as at least a part of the warp and / or the weft solves the above-mentioned problems, and in the fabric, the warp density and the weft density are 10 to 25 / inch. This is a preferred embodiment.

  According to the present invention, it is possible to provide a fabric that does not come off the screen door sash during actual use, storage, and transportation, and a polylactic acid monofilament that can be suitably used for the fabric.

  The polylactic acid resin used in the present invention is a polylactic acid resin obtained by polymerizing lactic acid mainly composed of L-lactic acid and / or D-lactic acid. Of these, a polylactic acid resin containing L-lactic acid as a main component is preferable from the viewpoint of keeping the melting point high in terms of price.

  The polylactic acid resin of the present invention preferably has a weight average molecular weight (Mw) of 100,000 to 300,000. By using a polylactic acid resin having an Mw of 100,000 to 300,000, moderate molecular chain entanglement can be obtained, and a polylactic acid monofilament having good stretchability and physical properties can be obtained.

  The polylactic acid resin of the present invention may be a monofilament made of a copolymer of a component copolymerizable with lactic acid, or a blended product with other thermoplastic polymer that can be blended. Examples of the copolymer include cyclic lactones such as ε-caprolactone, α-hydroxy acids such as α-hydroxyisobutyric acid and α-hydroxyvaleric acid, glycols such as ethylene glycol and 1,4-butanediol, Examples thereof include those obtained by copolymerizing one or more monomers selected from dicarboxylic acids such as acids and sebacic acid. Of these, cyclic lactones and glycols are preferred in view of polymer polymerization characteristics.

  Examples of blendable thermoplastic polymers may include aliphatic polyester polymers such as polycaprolactone, polybutylene succinate, and polyethylene succinate to reduce melt viscosity.

  However, in order to obtain the polylactic acid monofilament of the present invention, it is preferable that 95 to 100% by weight is a lactic acid component. If the copolymerization rate and / or blending rate is 95 to 100% by weight, a polylactic acid monofilament having a low melting point and excellent heat resistance can be obtained. Moreover, 3 weight% or less as a content of a preferable copolymerization component and / or blended material, More preferably, 1 weight% or less can be illustrated.

  The polylactic acid monofilament of the present invention may be formed by blocking the carboxyl group terminal with a compound having a hydroxyl group in the polylactic acid resin for the purpose of improving hydrolysis resistance. Examples of the compound having a hydroxyl group include higher alcohols having 6 or more carbon atoms such as octyl alcohol, lauryl alcohol and stearyl alcohol, and glycols such as ethylene glycol, diethylene glycol and 1,4-butanediol. By esterifying the carboxyl group at the terminal of the polylactic acid molecule with a compound having a hydroxyl group, the thermal stability during melt spinning and the temporal stability of the monofilament after melt spinning can be improved. Among these, from the viewpoint of stretchability, higher alcohols having 6 to 18 carbon atoms are preferable. In order to obtain the same effect, the carboxyl group may be reacted with one or more compounds selected from a carbodiimide compound, an epoxy compound, an oxazoline compound, an oxazine compound, and an aziridine compound.

  In order to give sufficient hydrolysis resistance, the carboxyl group terminal concentration is preferably 25 equivalent / ton or less, more preferably 15 equivalent / ton or less, further preferably 10 equivalent / ton or less, particularly preferably 0 to 0 equivalent. 5 equivalents / ton. The amount of the carboxyl end group is determined by immersing a precisely weighed sample (1 g) in 20 ml of o-cresol (5% moisture), dissolving at 145 ° C. for 10 minutes, and titrating with 0.02N KOH methanol solution. Can be sought. At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the monomer-derived carboxyl group terminal, and the oligomer-derived carboxyl group terminal are totaled. The carboxyl group terminal concentration obtained is obtained.

  The polylactic acid monofilament of the present invention may contain at least one colorant in advance in order to avoid strength reduction and environmental contamination in the dyeing process and to improve weather resistance. Colorants added include inorganic pigments such as titanium oxide and carbon black, as well as cyanine, styrene, phthalocyanine, anthraquinone, perinone, isoindolinone, anthraquinone, verinone, and isoindolinone. Examples thereof include, but are not limited to, quinophthalone, quinocridone, and thioindigo. The content of the colorant is preferably 0.01 to 4% by weight based on the weight of the polylactic acid monofilament. When the added amount of the colorant satisfies the range of 0.01 to 4% by weight, a polylactic acid monofilament having excellent color tone and physical properties can be obtained with good yarn production. The addition amount of the colorant is more preferably from 0.1 to 0.6% by weight based on the polymer, and still more preferably from 0.3 to 0.5%. There is no particular limitation on the addition method, and a method of mixing a master chip containing a pigment at a high concentration and a base chip before spinning can be exemplified.

  The polylactic acid monofilament of the present invention contains 0.1 to 5% by weight, more preferably 0.5 to 3% by weight of fatty acid bisamide and / or alkyl-substituted fatty acid monoamide in order to improve wear resistance. Also good. By setting the content of the fatty acid bisamide and / or the alkyl-substituted fatty acid monoamide within the above range, the slipperiness of the monofilament surface can be improved and excellent wear resistance can be imparted. Fatty acid bisamide refers to a compound having two amide bonds in one molecule such as saturated fatty acid bisamide, unsaturated fatty acid bisamide, aromatic bisamide, etc., for example, methylene biscaprylic amide, methylene biscapric amide, methylene bislaurin. Acid amide, methylene bis myristic acid amide, methylene bis palmitic acid amide, methylene bis stearic acid amide, methylene bis isostearic acid amide, methylene bis behenic acid amide, methylene bis oleic acid amide, methylene biserucic acid amide, ethylene biscapryl Acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bismyristic acid amide, ethylene bispalmitic acid amide, ethylene bisstearic acid amide, ethylene bisisostearic acid Amide, ethylene bis behenic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, butylene bis oleic acid amide, butylene bis erucic acid amide, hexamethylene Bistearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bisoleic acid amide, hexamethylene biserucic acid amide, m-xylylene bisstearic acid amide, m-xylylene bis-12-hydroxystearic acid amide, p- Xylylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′- Gioray Adipic acid amide, N, N′-dioleyl sebacic acid amide, N, N′-distearyl isophthalic acid amide, N, N′-distearyl terephthalic acid amide, methylene bishydroxystearic acid amide, ethylene bishydroxystearic acid amide , Butylene bishydroxystearic acid amide, hexamethylene bishydroxystearic acid amide, etc., and alkyl-substituted fatty acid monoamides are compounds having a structure in which amide hydrogen such as saturated fatty acid monoamides and unsaturated fatty acid monoamides are replaced with alkyl groups. For example, N-lauryl lauric acid amide, N-palmityl palmitic acid amide, N-stearyl stearic acid amide, N-behenyl behenic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-o Examples include rail stearic acid amide, N-stearyl erucic acid amide, and N-oleyl palmitic acid amide. The alkyl group may have a substituent such as a hydroxyl group introduced into its structure, for example, methylol stearamide, methylol behenic acid amide, N-stearyl-12-hydroxystearic acid amide, N-oleyl-12-hydroxystearic acid amide and the like are also included in the alkyl-substituted fatty acid monoamide of the present invention. Of these, fatty acid bisamides can be more preferably used because they are less reactive with polylactic acid because of the lower reactivity of amides, and are high in heat resistance and difficult to sublimate because of their high molecular weight. The fatty acid bisamide and the alkyl-substituted fatty acid monoamide may be added singly or a plurality of components may be mixed and used.

  Further, the polylactic acid monofilament of the present invention is within the range not impairing the effects of the present invention, matting agents such as titanium oxide, calcium carbonate, kaolin, clay, antioxidants, heat resistance agents, heat resistance agents, light resistance agents, Ultraviolet absorbers, antistatic agents, flame retardants, and the like can be included.

  However, since polylactic acid monofilaments are biodegradable and non-petroleum-based raw materials, and are used as products with a low environmental impact even when discarded, avoid the blending of petroleum-based polymers and copolymerization of these components as much as possible. In addition, it is preferable that the various additives not use any of the heavy metal compounds and environmental hormone substances as well as the compounds that are currently expected to be concerned.

  In addition, in order to improve the functionality of polylactic acid monofilament, the method of changing the shape of the cap hole is adopted, and the cross-sectional shape of polylactic acid monofilament is not only circular, but also flat, triangular, hollow, star-shaped It is good also as composite monofilaments, such as a core-sheath composite and a sea island type, as what has atypical cross sections and hollow parts, such as.

  The polylactic acid monofilament of the present invention must have a heat shrinkage stress at 80 ° C. of 0 to 0.04 cN / dtex, preferably 0 to 0.02 cN / dtex, more preferably 0 to 0.01 cN / dtex. is there.

  Conventionally, the shrinkage characteristics of polylactic acid filaments have been mainly discussed by the boiling water shrinkage rate. For example, the phenomenon that the screen sash is deformed by the shrinkage of the polylactic acid monofilament when it is applied to the screen sash is boiling water. The discussion from the shrinkage rate (boiling) was not enough. That is, when a monofilament having a high heat shrinkage stress is used even when the boiling yield is small, there is a concern about deformation such as a sash. Therefore, in the present invention, the shrinkage characteristic of the polylactic acid monofilament is defined by the shrinking force of the polylactic acid monofilament in a high temperature atmosphere, that is, the heat shrinkage stress.

  That is, the heat shrinkage stress at 80 ° C. indicates the force that the polylactic acid monofilament tends to shrink especially during storage in summer and at the time of actual use. For example, even when the monofilament has a low boiling water shrinkage rate, the heat shrinkage stress at 80 ° C. Is large, when it exceeds 0.04 cN / dtex, a polylactic acid monofilament having a sufficient force to deform the sash or the like is obtained. On the other hand, when the heat shrinkage stress at 80 ° C. is less than 0 cN / dtex, the polylactic acid monofilament is difficult to carry stress during storage or actual use. The quality of

  The polylactic acid monofilament of the present invention preferably has a fineness of 100 to 2000 dtex. If the fineness is 100 to 2000 dtex, a suitable fabric for screen doors can be obtained because the thickness becomes appropriate when the screen doors are applied. As for the fineness of a polylactic acid monofilament, it is more preferable that it is 200-1000 dtex, and 400-800 dtex can be illustrated as a still more preferable range.

  The polylactic acid monofilament of the present invention preferably has an elongation of 25 to 75%, and a more preferable range is 60 to 75%. When the elongation satisfies 25 to 75%, since it has an appropriate energy absorption capability, a woven fabric that does not easily come off from the sash is obtained even when a person or the like contacts the screen door.

  The strength of the polylactic acid monofilament of the present invention is not particularly limited, but in order to prevent fabric breakage due to the durability of the fabric and the collision of the human body when used in a screen door, the strength (g / denier) It is preferable that the strength applied with d) is 1 kgf or more. Although there is no particular upper limit to the strength, the strength is preferably 3 kgf or less in order to obtain polylactic acid monofilaments with good spinning properties.

  The polylactic acid monofilament of the present invention is required to have a primary yield stress of 0.5 to 1.3 cN / dtex, and a preferred range is 0.7 to 1.1 cN / dtex, and a more preferred range is 0.00. 8 to 1 cN / dtex can be exemplified.

  Monofilaments used for screen doors, etc. are required to be easy to install in order to improve screen door productivity, and when considering the workability of monofilament fabrics for screen door sashes, apply to a certain hardness and frame. It must be easy to bend. Polylactic acid monofilament is originally known to be hard and can be said to be a material that is difficult to work with. However, as a result of the study of the workability of polylactic acid monofilament by the present inventors, the workability is primary yield point stress. I found that it can be defined.

  That is, when the primary yield point stress is less than 0.5 cN / dtex, the polylactic acid monofilament begins to stretch at a low stress, and it becomes difficult to apply the woven fabric to the sash uniformly during the application. On the other hand, when the primary yield stress exceeds 1.3 cN / dtex, the polylactic acid monofilament is difficult to stretch, so it is difficult to bend at the time of construction on the sash, especially when the fabric is folded and fixed to the frame of the sash, and an appropriate stress. It is difficult to apply the woven fabric to the sash uniformly because it does not stretch.

  The polylactic acid monofilament of the present invention preferably has a boiling yield of 0 to 5% in order to ensure dimensional stability in the textile production process, more preferably 0 to 4%, and still more preferably 0 to 3%. The range of can be illustrated. When the range of 0 to 5% is satisfied, it is possible to obtain a net that does not easily come off from the sash even when placed in a high temperature atmosphere such as summer.

  Next, although the manufacturing method of the polylactic acid monofilament of the present invention will be described, the manufacturing method is not limited to this.

  First, the polylactic acid resin stored in the spinning hopper was supplied to a single-screw extruder type melt spinning apparatus and melt-spun. The molten polymer is weighed with a gear pump in accordance with the final fineness of the monofilament, filtered through a metal nonwoven fabric filter in a spinning pack, and spun from the die. The spun polymer is cooled and solidified in a cooling bath and then taken up by a first roller.

  The water content of the polylactic acid resin used for melt spinning is preferably 0 to 200 ppm in order to suppress hydrolysis of the polylactic acid resin, and is preferably stored in a storage tank filled with nitrogen gas.

  The spinning temperature depends on the melting point of the polylactic acid resin to be used. In order to obtain a polylactic acid monofilament having the characteristics of the present invention, a temperature higher than the spinning temperature of a normal polylactic acid monofilament, specifically, a melting point + 60 ° C. It is preferable to melt in the range of ˜melting point + 90 ° C.

  Immediately below the spinneret, the upper end is 0 to 5 cm below the spinneret surface, and a range of 1 to 5 cm from the upper end is surrounded by a heating tube and / or a heat insulating tube, and the spinning yarn has a spinning temperature of 0 to 50 ° C. In order to obtain the polylactic acid monofilament which has the characteristic of this invention, it is preferable to let it pass in a high temperature atmosphere.

  The extruded yarn that has passed through the high temperature atmosphere is then cooled and solidified in cooling water at 30 to 85 ° C., preferably 50 to 75 ° C., and the distance between the die surface and the cooling bath liquid surface is 1 to 10 cm, preferably 2 to 8 cm. In order to obtain the polylactic acid monofilament having the characteristics of the present invention, it is preferable that the extruded yarn is rapidly cooled in a state where the time in which the extruded yarn exists in the atmosphere is minimized.

  Although the detailed mechanism is not clear, considering the weight average molecular weight, moisture content, spinning temperature, distance from the die surface to the liquid surface, etc. of the above-mentioned polylactic acid resin, the molecular orientation within the single yarn and the inside and outside of the molecular structure By fixing the fiber structure of the undrawn yarn in a state in which the layer difference is reduced and the molecular density is set high, and the polymer discharged from the holes is separated from the air by setting the distance of the liquid surface from the die surface to a specific range. By rapidly quenching while suppressing the orientation due to shearing, the molecular orientation of the amorphous region of the polylactic acid monofilament after stretching can be suppressed.

  The polylactic acid unstretched monofilament yarn taken up is once wound or stretched between the first roller and the second roller without being wound once. For drawing, a warm water bath set at the drawing temperature is used, and the yarn after drawing is subjected to a predetermined relaxation treatment between the second roller and the third roller. After the oil agent is simultaneously applied to the polylactic acid monofilament using the arranged oil agent roller, the oil agent is relaxed through two hot plates arranged between the third roller and the fourth roller, and the polylactic acid monofilament is wound using a winder. Get.

  Here, the surface speed of the first roller, that is, the take-up speed is preferably 5 m / min to 30 m / min in order to obtain the polylactic acid of the present invention. It is considered that the yarn deformation immediately after discharging the nozzle hole is reduced by pulling the yarn at a low speed, so that the molecular orientation in the monofilament and the single yarn inner / outer layer difference in the fiber structure are reduced. The lower the take-up speed, the better. However, when the take-up speed is less than 5 m / min, the productivity deteriorates, which is not preferable.

  The unstretched yarn taken up at the take-up speed is drawn up once or continuously between the rollers without being taken up.

  The first-stage stretching is performed between the first roller and the second roller, and is used for the second-stage stretching as necessary. At this time, the stretching ratio in each stretching stage is not particularly limited, and stretching may be performed in three or more stages. Moreover, in order to fully bring out the effect in the relaxation heat treatment step described later, the draw ratio is preferably 2 to 6 times, and preferably 3 to 5 times.

  In order to obtain the polylactic acid monofilament of the present invention, it is preferable to relax the stretched yarn between the rollers. At this time, it is preferable to heat-treat between the second roller and the third roller using a dry heat oven, a hot plate, steam or the like. In the normal polylactic acid monofilament yarn production process, the relaxation treatment is performed only in one stage, but in the present invention, the relaxation treatment in two or more stages may be performed. The relaxation rate is preferably 0 to 20%, more preferably 5 to 20%, and still more preferably 10 to 20%. Here, if the relaxation rate is 0 or more, the molecular orientation of the amorphous region proceeds moderately, so that the effect of the present invention can be sufficiently obtained. On the other hand, when the relaxation treatment rate at the first stage is 20% or less, the yarn swaying in the relaxation treatment step is small and the yarn forming property is good.

  In ordinary drawing of polylactic acid monofilament, a method in which heat treatment is not performed (for example, Patent Document 2) or a method in which heat treatment is performed without relaxation (for example, Patent Document 3) is mainly employed. The reason is considered to be that polylactic acid monofilaments are softened under a high temperature atmosphere, so that the yarn swaying in the spinning process is increased and the spinning performance is deteriorated. Here, for example, a polylactic acid monofilament with sufficiently advanced orientation is considered to be able to withstand a relaxation heat treatment of about 3% because it has good thermal stability. However, it is difficult to obtain a good yarn forming property by the conventional manufacturing method.

  The point for obtaining a polylactic acid having a suppressed molecular orientation particularly in the amorphous region as in the present invention with good yarn production is the monofilament heating method in the stretching step and / or the relaxation treatment step. Street.

  B) A polylactic acid monofilament stretched at a magnification of 2 to 5 times is heated to a glass transition temperature of the polylactic acid resin + 70 ° C to 100 ° C under relaxation or tension of 0.85 to 1.4 times. Usually, when a polylactic acid monofilament stretched at a low magnification of 2 to 5 times is subjected to a relaxation heat treatment or a tension heat treatment of 0.85 to 1.4 times, the yarn-making property is deteriorated due to yarn shaking. In this case, the yarn oscillation is suppressed by giving a very high temperature of glass transition temperature + 70 ° C. to 100 ° C. during relaxation or tension of 0.85 to 1.4 times. That is, in the range of the glass transition temperature + 70 ° C. to 100 ° C., the molecular mobility in the amorphous region is increased, so that the polylactic acid monofilament contracts enough to suppress the yarn swinging of the polylactic acid monofilament. At this time, if the relaxation rate is 0.85 times or more, the monofilament is loosened more than the contraction of the molecular chain by heat, so that the yarn forming property is sufficient. In addition, when the molecular weight is 1.4 times or less, the orientation of the molecules proceeds appropriately, so that the effects of the present invention can be sufficiently obtained. When the relaxation rate is 0.85 to 1 time, the molecular chain is contracted by heat. Therefore, preliminary crystallization proceeds while relaxing the molecular chain. As the molecular orientation progresses, oriented crystals are generated in addition to thermal crystallization, so that a preliminary crystal that can be sufficiently crystallized in the step (b) described later is generated, and molecular chains in regions other than the preliminary crystal are sufficient. It is thought that it will be in a relaxed state. If the temperature applied at this time is not less than the glass transition temperature + 70 ° C., the molecular chains are sufficiently contracted to suppress yarn swinging, and if it is not more than the glass transition temperature + 100 ° C., the yarn-making property is hardly deteriorated due to thermal fusion.

  B) Heat-setting the polylactic acid monofilament after the treatment (a) at a temperature of crystallization temperature of the polylactic acid resin + 0 ° C. to + 40 ° C. while relaxing at a rate of 0.99 to 0.90. The molecular chain is sufficiently relaxed by the above-mentioned process, and the polylactic acid monofilament in which the preliminary crystal is formed is heat-treated at the crystallization temperature +0 to 40 ° C. Lactic acid is thought to be obtained.

  The aforementioned heat treatment step is most important in obtaining the monofilament of the present invention. For example, unlike the conventional method for producing polylactic acid monofilament disclosed in paragraph [0027] of Patent Document 3, etc., sufficient amorphous relaxation and crystal growth that could not be achieved from the viewpoint of yarn production by the conventional production method. Is achieved for the first time.

  The production method of the polylactic acid resin constituting the polylactic acid monofilament of the present invention is the method described in JP-A-6-65360 (direct dehydration condensation method) and the method described in JP-A-7-173266 (at least two kinds). A method in which a homopolymer is copolymerized and transesterified in the presence of a polymerization catalyst), a method described in US Pat. No. 2,703,316 (after dehydrating lactic acid once to form a cyclic dimer) Indirect polymerization method for ring-opening polymerization) or the like can be employed.

  In addition, an oil agent may be added to the polylactic acid monofilament of the present invention in order to improve surface smoothness characteristics. The oil agent may be aqueous or non-aqueous, but contains a smoothing agent as a main component, includes a surfactant, an antistatic agent, an extreme pressure agent component, and the like, and removes an active component in the polylactic acid resin. It is preferable to use an oil agent composition. For example, the emulsified component contained in the water emulsion has an action of changing the fiber structure of polylactic acid monofilament, and easily works to generate surface irregularities during stretching. Therefore, it is preferable to use a non-aqueous oil agent. Further, a preferred oil agent composition is, for example, a non-aqueous oil agent obtained by diluting an alkyl ether ester as a smoothing agent component, an alkylene oxide adduct of a higher alcohol as a surfactant component, and an organic phosphate salt as an extreme pressure agent component with a mineral oil. . By improving the surface smoothness characteristics, deterioration of the monofilament due to friction in the weaving process can be reduced during actual use.

  The oil agent can be applied by a method such as an oil agent roll or an oil agent spray at an arbitrary place in the yarn production process.

  The woven fabric of the present invention can be suitably used for applications such as screen door sashes and the like, and the polylactic acid monofilament of the present invention described above can be used for at least a part of warp and / or weft. preferable. As described above, by using the monofilament of the present invention having a small heat shrinkage stress in a high temperature atmosphere, for example, even when it is constructed in a certain frame, it does not come off the frame during storage, transportation or actual use. A woven fabric can be provided. However, in order to maximize the effects of the present invention, 90% by weight or more of the woven fabric is preferably the monofilament of the present invention, and it is more preferable that all of the warp and / or the weft are the monofilament of the present invention. .

  Moreover, it is a preferable aspect that the woven fabric of the present invention has a warp density and a weft density of 10 to 25 yarns / inch. When the warp density and the weft density are 10 to 25 yarns / inch, not only an excellent pest-supplement effect can be obtained when used as a screen door, but it is hardly affected by wind. More preferred warp density and weft density are 10 to 25 yarns / inch, and further preferred warp density and weft density are 15 to 23 yarns / inch.

  The woven fabric of the present invention is characterized by the use of the polylactic acid monofilament of the present invention having excellent heat shrinkage properties, and its production method is not limited in any way. For example, after warping the monofilament, It can be manufactured by a method such as weaving.

  Hereinafter, embodiments of the present invention will be described in more detail by way of examples. The definition and measurement method of the characteristics used in the specification text and examples are as follows.

  [Fineness]: Measured according to JIS L1013 8.3.1 B method.

  [Strength and Elongation]: Samples were measured with a “TENSILON” UCT-100 manufactured by Orientec Corp. under constant speed elongation conditions shown in JIS L1013 8.5.1 standard time test. At this time, the grip interval was 25 cm, the pulling speed was 30 cm / min, and the number of tests was 10 times. The elongation at break was determined from the elongation at the point showing the maximum strength in the SS curve.

[Boiling]: Measured according to the method of JIS L1013. Cases were collected from the yarn package with a measuring machine, and the length L1 was measured by applying a load of 0.09 cN / dtex. Subsequently, the load was removed and the treatment was performed in boiling water for 30 minutes. The casserole after the boiling water treatment was air-dried, the load of 0.09 cN / dtex was applied again to measure the casserole length L2, and the boiling yield was measured by the following formula.
Boiling yield (%) = [(L1-L2) / L1] × 100

  [Weight average molecular weight]: Measured by using gel permeation chromatography 2690 manufactured by Waters Co., Ltd. with polystyrene as a standard. The measurement was performed twice and the average value was obtained.

  [Heat shrinkage stress at 80 ° C.]: Using a heat shrinkage measuring machine TST2 type manufactured by LENZING INSTRUMENTS, applying an initial load of 1/33 g of the raw yarn fineness (dtex) to be measured, the heating rate is 10 ° C./min at 40 ° C. The temperature was raised to ˜140 ° C. and a heat shrink stress curve was obtained. After correcting the obtained heat shrinkage stress curve so that the heat shrinkage stress at the measurement start temperature (40 ° C.) was zero, the heat shrink stress (cN / dtex) at 80 ° C. was obtained. The measurement was performed twice and the average value was obtained.

  [Primary yield point stress]: In the SS curve obtained by the strength and elongation measurement methods, the stress at the time when the SS curve yielded after the initial rise was read from the SS curve.

[Workability]: The time required to finish the construction of a polylactic acid monofilament fabric on a commercially available screen door sash (outside height 200 cm, outside size width 90 cm, no intermediate rail), and a commercially available polypropylene monofilament screen door fabric The time taken to finish construction on a similar screen door sash was measured and determined by the following equation. That is, when the value is 1, the workability is the same as that of a polypropylene monofilament fabric, and the lower the value is, the better the workability is. The measurement was repeated three times and the average value was determined.
Workability = Polylactic acid monofilament fabric construction time / polypropylene monofilament fabric construction time

[Fabric removal from the sash and sash deformation ratio]: A commercially available aluminum door sash (outer height 200 cm, outer width 90 cm, no intermediate cross) with a screen door fabric stretched in a dry heat oven at 75 ° C Heat treated for 15 minutes. After the heat treatment, the sash was taken out and the appearance of the screen door fabric was removed from the sash. Then, the sash dimension in the width direction was measured, and the sash deformation rate was determined according to the following equation.
Sash deformation rate = sash width direction dimension after heat treatment / sash width direction dimension before heat treatment × 100

[Production Example 1] (Production of polylactic acid resin)
Lactide prepared from L-lactic acid having an optical purity of 99.5% was converted into bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10,000: 1), GE Ultranox 626 (lactide to Ultranox 626 weight). The polymer was polymerized in a nitrogen atmosphere at 180 ° C. for 350 minutes in the presence of a ratio = 99.8: 0.2), and a polymer having a weight average molecular weight of 200,000, a glass transition temperature of 57 ° C., a crystallization temperature of 111 ° C. and a melting point of 168 ° C. A lactic acid resin was obtained. The obtained resin was dried in a vacuum dryer at 110 ° C. for 8 hours to obtain a resin P1 having a moisture content of 58 ppm.

[Production Example 2] (Production of original polylactic acid resin)
The polylactic acid polymer P1 and carbon black were supplied to a twin-screw extrusion kneader so that the weight ratio was 96: 4, and kneaded at a cylinder temperature of 190 ° C. to obtain an original polylactic acid resin. The obtained resin was dried in a vacuum dryer at 110 ° C. for 8 hours to obtain a resin P2 having a moisture content of 62 ppm.

Example 1
P1 and P2 mixed so that the final concentration of carbon black is 0.4% by weight are stored in a spinning hopper filled with nitrogen and supplied to a uniaxial extruder having a diameter of 30 mm (L / D = 25). Melted at ℃.

  The molten polymer was weighed with a gear pump so that the final fineness of the monofilament would be the value shown in Table 1, and then filtered through a 100 μm metal filter in a spinning pack, 30 holes with a hole diameter of 1.0 mmφ and a hole length of 2.5 mm. It was spun from the base.

  The spun polymer was cooled and solidified in a 65 ° C. hot water cooling bath having a liquid level at a position 4 cm below the die surface, and then taken up by a first roller at a surface speed of 20 m / min. The polylactic acid unstretched monofilament yarn taken up was stretched between the first roller and the second roller so that the magnification was 4.34 times without being wound once. A hot water bath was used for stretching, and the stretching temperature was set to 85 ° C.

  The stretched yarn is subjected to a 4% relaxation treatment using a 145 ° C. dry heat oven between the second roller and the third roller, and then a 120 ° C. dry heat oven is used between the third roller and the fourth roller. The sample was relaxed to a relaxation rate of 1% and wound up using a winder. The characteristics of the obtained polylactic acid monofilament are shown in Table 1. It should be noted that an oil agent {80% by weight of ion exchange water, 12% by weight of a smoothing agent component (isostearyl oleate), between the fourth roller and the winder so that the final adhesion amount to the polylactic acid monofilament is 0.4% by weight, Then, a nonionic surfactant (8 wt% mixed suspension of ethylene oxide 10 mol adduct of hardened castor oil) was applied using an oil roller. The obtained polylactic acid monofilament was warped and woven using a slewer loom under the conditions of a weaving width of 91 cm, a length of 18 / inch, and a width of 18 / inch. Table 1 shows the evaluation results after the obtained woven fabric was applied to a commercially available screen door sash (outside dimension height 200 cm, outside dimension width 90 cm, no intermediate crosspiece).

(Example 2)
The polylactic acid unstretched monofilament taken up by the first roller was stretched between the first roller and the second roller so that the magnification was 3.52, and the monofilament after the first stage stretching was 1.23 times The film was stretched at 140 ° C. between the second roller and the third roller so that the relaxation rate was 5% using a dry heat oven at 150 ° C. between the third roller and the fourth roller. Except for this, the same procedure as in Example 1 was performed, and the evaluation results are shown in Table 1.

(Example 3)
The evaluation was performed in the same manner as in Example 2 except that the draw ratio of the first stage was 3.33 times and the draw ratio of the second stage was 1.3 times. The evaluation results are shown in Table 1.

(Comparative Example 1)
A polylactic acid unstretched monofilament taken up by the first roller is stretched between the first roller and the second roller so that the magnification is 3.96, and a second roller that circulates the stretched monofilament at the same speed; The same as in Example 1 except that the treatment was performed at 30 ° C. between the third rollers and the treatment was performed so that the relaxation rate was 0% using a 125 ° C. dry heat oven between the third roller and the fourth roller. The evaluation results are shown in Table 1. .

(Comparative Example 2)
Table 1 shows the results obtained in the same manner as in Example 1 except that the temperature of the dry heat oven between the second roller and the third roller was 115 ° C. However, since yarn breakage occurred frequently in the yarn making process, weaving was impossible and evaluation as a screen door fabric could not be performed.

(Comparative Example 3)
It was stretched by 4.52 times between the first roller and the second roller, stretched by 1.56 times between the second roller and the third roller, and the second stage stretching temperature was 140 ° C., The evaluation was performed in the same manner as in Example 2 except that 0% relaxation was given between the third roller and the fourth roller, and heat of 145 ° C. was applied between the third roller and the fourth roller. It was shown to.

Example 4
The evaluation was performed in the same manner as in Example 1 except that the weave density was set to 8 vertical / inch and 8 horizontal / inch, and the evaluation results are shown in Table 1.

(Example 5)
The evaluation was performed in the same manner as in Example 1 except that the weaving density was 28 / inch and 28 / inch, and the evaluation results are shown in Table 1.

  As is clear from the examples and comparative examples, the polylactic acid monofilament of the present invention and the fabric using the same are excellent in workability, and even when stretched on a fixed length frame such as a screen door sash, it depends on the use environment and storage environment. The dimensional change is small, and there are few problems such as framing of the fabric.

Claims (5)

A polylactic acid monofilament using a polylactic acid resin, wherein the heat shrinkage stress at 80 ° C. is 0 to 0.04 cN / dtex, and the primary yield point stress is 0.5 to 1.3 cN / dtex. Polylactic acid monofilament. The polylactic acid monofilament according to claim 1, wherein the yield is 0 to 5% and the elongation is 25 to 70%. A woven fabric comprising the polylactic acid monofilament according to claim 1 or 2 as at least a part of warp and / or weft. The woven fabric according to claim 3, wherein the warp density and the weft density are 10 to 25 yarns / inch. In the method for producing a polylactic acid monofilament, the molten polylactic acid resin is discharged from a die, cooled, stretched and wound up, and the following (a) to (c) are satisfied at the same time. .
(A) The melted polylactic acid resin in the range of + 60 ° C. to melting point + 90 ° C., and the extruded yarn from the die, in the range of 1 to 10 cm from the die surface, in the cooling water at a temperature of 30 to 85 ° C. Solidify by cooling.
(B) The cooled filament is taken up at a speed of 5 m / min to 30 m / min, stretched at a magnification of 2 to 5 times, and then glass of polylactic acid resin under relaxation or tension of 0.85 to 1.4 times Apply heat at transition temperature + 70 ° C to 100 ° C.
(C) The polylactic acid monofilament after the treatment (b) is relaxed by a factor of 0.99 to 0.90, and heat-set in the range of the crystallization temperature of the polylactic acid resin + 0 ° C. to + 40 ° C.