JP5586452B2 - Method for producing void-containing yarn - Google Patents

Description

  The present invention relates to a method for producing a void-containing yarn.

In recent years, various efforts have been made to improve the functionality, aesthetics, and design of fibers. For example, by changing the cross-sectional shape of the fiber, improving water absorption, or modifying the polymer, the lightness is improved, the fibrillation is improved, or the deep color is improved (for example, , See Patent Document 1).
However, in the method for producing a fiber having a hollow structure described in Patent Document 1, in order to achieve a high hollow ratio in order to reduce the weight of the fiber, there is a technique in which a polymer melt-extruded from a discharge hole of a die is bonded. It is necessary and the process is complicated.

A hollow structure fiber can also be produced by adding a sodium sulfonate compound in the polymerization step, and melt-kneading polystyrene or polymethylmethacrylate into the resulting polymer pellets and melt-extruding from a melt spinning hollow die. (See Patent Document 2).
However, in the method described in Patent Document 2, it is difficult to obtain a uniform product because it requires complicated measures to manage the ratio of additive materials and the like, and it is difficult to obtain a uniform product. Therefore, there is a problem that separation is difficult during recycling, and in some cases it must be discarded.

  As a fiber having improved aesthetics and design, it is strongly desired to provide a fiber having a metallic luster (shininess). As such a fiber, an excellent fiber such as a reflectance has been proposed by having a void inside (refer to Patent Document 3). Such a fiber can be produced by drawing a filament having a fine crystal nucleus inside. Therefore, the quality of such fibers largely depends on the properties of the yarn for producing the yarn, that is, the crystallite size and crystallinity of the crystal nucleus contained in the yarn.

However, the crystallite size of the crystal nuclei contained in the strand is determined by the extrusion rate of the molten polymer when the strand is produced, the ambient temperature until it is cooled after being extruded, The temperature was different depending on slight changes in conditions such as the winding speed of the cooled yarn. For this reason, even if the strand is stretched, the reflectance is not sufficient and a metal-like gloss cannot be obtained, or there is a disconnection at the time of stretching, and a fiber having a metal-like gloss cannot be produced stably. It was a problem in terms.
So far, in the production of the yarn shown in Patent Document 3, etc., the type of resin used as a raw material and the drawing conditions have been studied, but the properties of the yarn have not been sufficiently studied and have a metallic luster. The problem was that the fibers could not be produced stably.

  Therefore, it is desired to provide a method for improving the quality of the yarn used in the production of the yarn, and stably and efficiently producing a yarn having a metallic luster, high reflectivity, and excellent aesthetics and design. The current situation is.

JP 2002-173824 A JP 2005-256243 A JP 2009-191383 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is capable of aging fine crystal nuclei contained in void-containing yarn-producing yarns to a desired crystallite size, and aging void-containing yarn-producing yarns containing the aged crystal nuclei. An object of the present invention is to provide a method for producing a void-containing yarn that can stably and efficiently produce a void-containing yarn having a metallic luster, high reflectivity, and excellent aesthetics and design.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies and as a result, obtained the following findings. That is, the quality of the reflectivity and the like of the void-containing yarn (also referred to as void yarn or void-containing yarn) is greatly influenced by the crystallite size of the crystal nucleus inside the void-containing yarn manufacturing yarn used for the production of the void-containing yarn. Therefore, a resin melt-extruded in a thread form from a nozzle is passed through water to form a void-containing yarn-producing yarn that contains crystal nuclei having a crystallite size of (010) plane of less than 2 nm inside. A process for forming a void-containing yarn and a maturation void-containing yarn by aging the crystal nucleus until the crystallite size of the crystal plane of the (010) plane in the void-containing yarn-producing yarn is 2 nm to 5 nm. A process for forming an aged void-containing yarn for forming an aged void-containing yarn, and a process for forming the aged void-containing yarn for producing a yarn, thereby forming an independent cavity inside the aged void-containing yarn for producing a yarn. A void-containing yarn manufacturing method comprising: forming a void-containing yarn, wherein the fine crystal nucleus contained in the void-containing yarn-producing yarn can be aged to a desired crystallite size, and the aged crystal nucleus Using the yarn for producing aged void-containing yarns that encapsulate, it has been found that a void-containing yarn having a metallic luster, high reflectivity and excellent aesthetics and design properties can be stably and efficiently produced, The present invention has been completed.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A void-containing yarn for forming a void-containing yarn for producing a void-containing yarn, in which a resin melt-extruded in a thread form from a nozzle is passed through water and contains a crystal nucleus having a crystallite size of (010) plane of less than 2 nm inside A process for forming a yarn for yarn production, and ripening the crystal nucleus until the crystallite size of the crystal plane of the (010) plane in the void-containing yarn production yarn is 2 nm to 5 nm, for producing a mature void-containing yarn A process for forming an aged void-containing yarn for forming a yarn, and forming an independent cavity inside the yarn for producing an aged void-containing yarn by stretching the yarn for producing an aged void-containing yarn A void-forming process comprising the steps of: forming a void-containing yarn.
<2> The void-containing yarn according to <1>, wherein the crystal nucleus is aged until the crystallinity of the void-containing yarn-producing yarn is 5% to 15% in the yarn forming step for producing the matured void-containing yarn. It is a manufacturing method.
<3> Any of the aging void-containing yarn production process is performed at 5 ° C. or more and 15 ° C. or less for at least 3 days, 15 ° C. or more and 25 ° C. or less for at least 12 hours, or 25 ° C. or more and 45 ° C. or less for at least 1 hour. The void-containing yarn production method according to any one of <1> to <2>, wherein the yarn is aged under such conditions.
<4> The void-containing yarn production method according to any one of <1> to <3>, wherein the cavity forming step is performed by a necking drawing method.
<5> The void-containing yarn production method according to any one of <1> to <4>, wherein the temperature of water is 5 ° C. to 30 ° C. in the yarn forming step for producing the void-containing yarn.
<6> The method for producing a void-containing yarn according to any one of <1> to <5>, wherein the resin is a crystalline polymer.
<7> L when the cavity is oriented in the stretching direction, the average length of the cavity is L (μm), and the average diameter of the cavity in the direction orthogonal to the orientation direction of the cavity is r (μm). The void-containing yarn production method according to any one of <1> to <6>, wherein the / r ratio is 10 or more.
<8> The method for producing a void-containing yarn according to any one of <1> to <7>, wherein the reflectance of the void-containing yarn is 50% or more.

  According to the present invention, the above-described problems can be solved and the object can be achieved, and the present invention provides fine crystal nuclei contained in the void-containing yarn-manufacturing yarn to a desired crystallite size. Using the yarn for producing aged void-containing yarn that can be aged and encapsulating the aged crystal nucleus, the void-containing yarn having a metallic luster, high reflectivity and excellent aesthetics and design is stably obtained. A method for producing a void-containing yarn that can be produced efficiently can be provided.

FIG. 1A is an example of a cross-sectional view of a void-containing yarn obtained by the method for producing a void-containing yarn of the present invention. FIG. 1B is an example of a cross-sectional view of a void-containing yarn obtained by the method for producing a void-containing yarn of the present invention. FIG. 2A is a diagram for explaining an aspect ratio, and is a perspective view of a void-containing yarn. FIG. 2B is a view for explaining the aspect ratio, and is a cross-sectional view taken along the line A-A ′ of the void-containing yarn in FIG. 2A. FIG. 2C is a view for explaining the aspect ratio, and is a B-B ′ sectional view of the void-containing yarn in FIG. 2A. FIG. 3A is a perspective view of the void-containing yarn for explaining the aspect ratio. FIG. 3B is a view for explaining the aspect ratio, and is a cross-sectional view taken along the line A-A ′ of the void-containing yarn in FIG. 3A. FIG. 3C is a diagram for explaining the aspect ratio, and is a B-B ′ sectional view of the void-containing yarn in FIG. 3A. FIG. 4 is a diagram illustrating an example of a drawing method in the method for producing a void-containing yarn of the present invention. FIG. 5 is a diagram showing the relationship between annealing time, crystallite size, crystallinity, and reflectance in the process of forming a mature void-containing yarn. FIG. 6 is a graph showing the relationship between the crystallite size of the (010) plane of the crystal nucleus of the void-containing yarn-producing yarn and the matured void-containing yarn-producing yarn and the yield of the void-containing yarn. Vertical axis: yield of void-containing yarn (%), horizontal axis: crystallite size (nm) on (010) plane. FIG. 7 is a diagram showing the relationship between the crystallinity of the void-containing yarn-producing yarn and the matured void-containing yarn-producing yarn and the yield of the void-containing yarn. Vertical axis: yield of void-containing yarn (%), horizontal axis: crystallinity (%).

(Method for producing void-containing yarn)
The void-containing yarn production method of the present invention includes at least a void-forming yarn-producing yarn forming step, an aged void-containing yarn-producing yarn forming step, and a cavity forming step, and if necessary, other These steps are included.

<Thread forming process for producing void-containing yarn>
The void-forming yarn-producing yarn forming step is a step of forming a void-containing yarn-producing yarn that includes a crystal nucleus. Specifically, a void-containing yarn-producing yarn is produced by melt spinning a resin composition containing at least a resin. That is, the resin composition is produced by drying, melting with an extruder, melting and discharging from a melt spinneret, cooling, and then winding.

<< Resin composition >>
The resin composition contains at least a thermoplastic resin, and further contains other components as necessary.
There is no restriction | limiting in particular as said thermoplastic resin, Although it can select suitably according to the objective, It is preferable that it is a polymer which has crystallinity.

-Polymer having crystallinity-
In general, polymers are divided into crystalline polymers and amorphous (amorphous) polymers. The crystalline polymer is not usually 100% crystalline, a crystalline region in which long chain molecules are regularly arranged in a molecular structure, and an amorphous region that is not regularly arranged. Is included.
In the present invention, the crystalline polymer may contain at least the crystalline region in the molecular structure, and the crystalline region and the amorphous region may be mixed, but only the crystalline polymer It is particularly preferred that

The polymer having crystallinity is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyolefin resin, polyamide resin, polyester resin, polyacetal (POM), syndiotactic polystyrene (SPS), Examples include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), liquid crystal polymer (LCP), and fluororesin. Two or more of these polymers may be blended or copolymerized.
Among these, from the viewpoint of mechanical strength and production, a resin that melts at about 300 ° C. or less is preferable, a polyolefin resin, a polyester resin, or a polyamide resin is more preferable, and a polyester resin is particularly preferable.

The melt viscosity of the crystalline polymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 Pa · s to 1,000 Pa · s, more preferably 70 Pa · s to 750 Pa · s. 80 to 450 Pa · s is more preferable. When the melt viscosity is 50 Pa · s to 1,000 Pa · s, the shape of the melt-spun extruded from the nozzle during spinning is stable, and it is easy to form a uniform yarn containing void-containing yarn. preferable. In addition, when the melt viscosity is 50 Pa · s to 1,000 Pa · s, the viscosity of the resin becomes appropriate during spinning, and it is easy to extrude from the nozzle. This is preferable in that the diameter is stable.
Here, the melt viscosity can be measured by, for example, a plate type rheometer, a capillary rheometer, or the like.

There is no restriction | limiting in particular as intrinsic viscosity (IV: Intrinsic Viscosity) of the polymer which has the said crystallinity, Although it can select suitably according to the objective, 0.4-1.5 are preferable, 0.6-1 .2 is more preferable, and 0.7 to 1.0 is particularly preferable. When the yarn for producing an aged void-containing yarn is used for the production of a void-containing yarn, the larger the IV, the easier to express a cavity at the time of drawing, but when 0.4 to 1.5, Even if it is easy to extrude the molten resin, the resin flow is stable and it is difficult for stagnation to occur, the quality is stable, even when a molten resin filter is installed during spinning, It is difficult to apply a load to the filter, the resin flow is stable and it is difficult for stagnation to occur, the tensile strength is increased, and the stretching tension is properly maintained at the time of stretching. It is preferable in terms of being easy to stretch uniformly and being difficult to apply a load to the apparatus, and further being difficult to break the product (void-containing yarn) and improving physical properties.
Here, the intrinsic viscosity (IV) can be measured by, for example, an Ubbelohde viscometer.

There is no restriction | limiting in particular as melting | fusing point (Tm) of the polymer which has the said crystallinity, Although it can select suitably according to the objective, 40 to 350 degreeC is preferable, 100 to 300 degreeC is more preferable, 150 degreeC More preferred is ~ 260 ° C. When the melting point is 40 ° C. to 350 ° C., it is easy to maintain the average diameter of the void-containing yarn-producing yarn within a temperature range expected for normal use, and specially required for processing at a high temperature Even if it does not use especially a technique, it is preferable at the point which can manufacture the said yarn for void containing yarn manufacture uniformly.
Here, the melting point can be measured by, for example, a differential thermal analyzer (DSC).

There is no restriction | limiting in particular as a weight average molecular weight of the polymer which has the said crystallinity, Although it can select suitably according to the objective, 5,000-1,000,000 are preferable and 10,000-800,000 are More preferably, 15,000-700,000 is still more preferable. If the weight-average molecular weight is less than 5,000, when the void-containing yarn-manufacturing yarn is used for the production of void-containing yarn, there is a concern of breaking during stretching, and the weight-average molecular weight is 1,000,000. If it exceeds 000, the void-containing yarn-producing yarn may be difficult to be stretched, and even if it is stretched, cavities may be difficult to develop. On the other hand, when the weight average molecular weight is 15,000 to 700,000, it is preferable from the viewpoint that both the ease of drawing the void-containing yarn-producing yarn and the ease of expression of voids can be achieved.
Here, the weight average molecular weight can be measured, for example, by a gel permeation chromatography (GPC Gel Permeation Chromatography) method.

--- Polyolefin resin--
The polyolefin resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyethylene, polypropylene (PP), a random copolymer of ethylene and propylene, and a block copolymer of ethylene and propylene. Random copolymers of ethylene and α-olefin (eg, 1-octene, 1-hexene, etc.), random copolymers of propylene and α-olefin (eg, 1-octene, 1-hexene, etc.) Can be mentioned.
Among these, polypropylene, a random copolymer of ethylene and propylene, and a block copolymer of ethylene and propylene are preferable, and a random copolymer of polypropylene and ethylene and propylene is particularly preferable.

--- Polyamide resin--
There is no restriction | limiting in particular as said polyamide resin, According to the objective, it can select suitably, For example, polycaproamide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide ( Nylon 66), polyhexamethylene sebamide (nylon 6/10), polyhexamethylene dodecamide (nylon 6/12), polyundecane adipamide (nylon 11/6), polyundecanamide (nylon 11) , Polydodecanamide (nylon 12), polytrimethylhexamethylene terephthalamide, polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalate / isophthalamide (nylon 6T / 6I), polybis (4-aminocyclohexyl) methane dodecamide (Nairro PACM12), polybis (3-methyl-4-aminocyclohexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylenehexa And hydroterephthalamide (nylon 11T (H)).
Among these, nylon 6, nylon 66, nylon 11, nylon 12, nylon 6/10, nylon 6/12, and nylon 11/6 are preferable, and nylon 6, nylon 66, and nylon 11 are particularly preferable.

--- Polyester resin--
The polyester resin is a polymer having an ester bond obtained by a polycondensation reaction of a dicarboxylic acid component and a diol component as a main bond chain of the main chain.

  The dicarboxylic acid component is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, oxycarboxylic acids, and polyfunctional acids. Can be mentioned. Among these, aromatic dicarboxylic acids are particularly preferable.

The aromatic dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, naphthalenedicarboxylic acid, diphenoxyethanedicarboxylic acid , 5-sodium sulfoisophthalic acid and the like.
Among these, terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, and naphthalenedicarboxylic acid are preferable, and terephthalic acid, diphenyldicarboxylic acid, and naphthalenedicarboxylic acid are more preferable.

Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, eicoic acid, adipic acid, sebacic acid, dimer acid, dodecanedioic acid, maleic acid, and fumaric acid.
Examples of the alicyclic dicarboxylic acid include cyclohexyne dicarboxylic acid.
Examples of the oxycarboxylic acid include p-oxybenzoic acid.
Examples of the polyfunctional acid include trimellitic acid and pyromellitic acid.

There is no restriction | limiting in particular as said diol component, According to the objective, it can select suitably, For example, aliphatic diol, alicyclic diol, aromatic diol, diethylene glycol, polyalkylene glycol etc. are mentioned.
Of these, aliphatic diols are particularly preferred.

Examples of the aliphatic diol include ethylene glycol, propane diol, butane diol, 1,4 butylene glycol, pentane diol, hexane diol, neopentyl glycol, triethylene glycol, and the like.
Among these, ethylene glycol, 1,4 butylene glycol, propanediol, and butanediol are particularly preferable.
Examples of the alicyclic diol include cyclohexanedimethanol.
Examples of the aromatic diol include bisphenol A and bisphenol S.

Specific examples of such a polyester resin include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PTT (polytrimethylene terephthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate) PLA ( Polylactic acid), PBS (polybutylene succinate), PHN (polyhexamethylene naphthalate), PHT (polyhexamethylene terephthalate) and the like.
Among these, PET, PBT, PEN, and PBS are preferable, and PET and PBT are particularly preferable.

  There is no restriction | limiting in particular as a number average molecular weight of the said polyester resin, Although it can select suitably according to the objective, 12,000-40,000 are preferable, 18,000-40,000 are more preferable, 18, More preferably, it is 500-30,000. When the number average molecular weight is less than 12,000, voids tend to be easily developed, but the mechanical strength of the void-containing yarn-producing yarn may be insufficient during spinning. If it exceeds 000, polymerization of the void-containing yarn-producing yarn may be difficult.

There is no restriction | limiting in particular as melt viscosity of the said polyester resin, Although it can select suitably according to the objective, 50 Pa.s-700 Pa.s are preferable, 70 Pa.s-500 Pa.s are more preferable, 80 Pa.s ˜300 Pa · s is more preferable. The higher the melt viscosity, when the yarn for producing an aged void-containing yarn is used for the production of a void-containing yarn, it is easy to develop a cavity at the time of drawing, but the melt viscosity is 50 Pa · s to 700 Pa · s. In spinning, the resin is easy to extrude, and the resin flow is stable and the stagnation is difficult to occur, which is preferable in terms of stable quality.
In addition, when the melt viscosity is 50 Pa · s to 700 Pa · s, when the yarn for producing an aged void-containing yarn is used for producing a void-containing yarn, the draw tension is appropriately maintained at the time of drawing. It is preferable in that it can be easily stretched uniformly and is difficult to break.
Furthermore, when the melt viscosity is 50 Pa · s to 700 Pa · s, it is easy to maintain the form of the molten resin extruded from the nozzle during spinning, and it is possible to stably form or the product is difficult to break. It is preferable in terms of improving physical properties.

  In addition, as the polyester resin, the dicarboxylic acid component and the diol component may each be polymerized to form a polymer, and the dicarboxylic acid component and / or the diol component may be a combination of two or more. It may be polymerized to form a polymer. Further, as the polyester resin, two or more kinds of polymers may be blended and used.

  In the blend of two or more kinds of polymers, the polymer added to the main polymer is closer to the melt viscosity and the intrinsic viscosity than the main polymer, and the amount added is smaller when spinning. It is preferable in that the physical properties are increased during extrusion of the molten resin, and the extrusion becomes easy.

  In addition, a resin other than the polyester resin may be added to the polyester resin for the purpose of improving the flow characteristics of the polyester resin, controlling light transmittance, and improving the adhesion with the coating solution.

-Other ingredients-
The other components in the resin composition are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include fillers, heat stabilizers, antioxidants, ultraviolet absorbers, organic lubricants, and cores. Agents, dyes, pigments, flame retardants, mold release agents, dispersants, coupling agents and the like.
Whether or not the other components contributed to the development of the voids in the void-containing yarn is detected in components other than the polymer having crystallinity (for example, each component described later) in the void or at the interface portion of the void. It can be determined by whether or not. For example, it can be detected by a scanning electron microscope with an energy-dispersive X-ray analyzer or a microscopic Raman method.

---- Antioxidant ---
There is no restriction | limiting in particular as said antioxidant, According to the objective, it can select suitably, For example, a phenol type compound, a sulfur type compound, a phosphorus type compound etc. are mentioned. These may be used alone or in combination of two or more.
Among these, a known hindered phenol is particularly preferable as the antioxidant. Examples of the hindered phenol include antioxidants commercially available under trade names such as Irganox 1010 (manufactured by Ciba Specialty Chemicals), Sumilizer BHT, Sumilizer GA-80 (all of which are manufactured by Sumitomo Chemical Co., Ltd.). Agents and the like.
Further, the antioxidant can be used as a primary antioxidant and further combined with a secondary antioxidant. Examples of the secondary antioxidant include antioxidants commercially available under trade names such as Sumilizer TPL-R, Sumilizer TPM, Sumilizer TP-D (all manufactured by Sumitomo Chemical Co., Ltd.). It is done.

---- Release agent ---
The release agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plant waxes such as carnauba wax, animal waxes such as beeswax and lanolin; mineral waxes such as montan wax; Examples include petroleum waxes such as paraffin wax and polyethylene wax; and oil-based waxes such as castor oil or derivatives thereof and fatty acids or derivatives thereof.
Examples of the higher fatty acid derivatives include esters of higher fatty acids such as lauric acid, stearic acid, and montanic acid with monovalent or divalent alcohols.

---- Flame retardant ---
There is no restriction | limiting in particular as said flame retardant, Although it can select suitably according to the objective, A brominated flame retardant is especially preferable. As the brominated flame retardant, organic halogen flame retardants such as high molecular weight organic halogen compounds and low molecular weight organic halogen compounds may be used singly or in combination of two or more. Moreover, you may use a phosphorus flame retardant and an inorganic flame retardant.

<< Method for forming yarn for producing void-containing yarn >>
-Melting method-
There is no restriction | limiting in particular as a method of fuse | melting the said resin composition, According to the objective, it can select suitably.
There is no restriction | limiting in particular as the temperature of the said heating, According to the kind etc. of resin in the said resin composition, it can select suitably. The molten resin composition becomes a high-temperature viscous liquid and is extruded from a nozzle. The molten resin composition is preferably devolatilized as necessary.

-Spinning method-
Spinning of the molten resin composition is performed by extruding the resin composition from a nozzle into a thread and cooling.

−−Nozzle−−
The nozzle is formed with a large number of small holes, and the molten resin composition is extruded through the nozzle, whereby the resin composition can be formed into a thread.
There is no restriction | limiting in particular as a shape of the hole of the said nozzle opening part, According to the objective, it can select suitably, For example, a circular shape, an atypical shape, etc. are mentioned. The variant means various variants that are not circular (perfect circles), for example, a gear, an ellipse, a petal, a multileaf, a star, a C, a Y, a cross, and a well. Etc.
The shape of the cross-section orthogonal to the extrusion direction of the resin composition of the void-containing yarn manufacturing element yarn is determined by the shape of the hole in the nozzle opening, and thereby the cross-section orthogonal to the drawing direction of the void-containing yarn. The shape of is also determined.

-Extrusion speed-
The void-containing yarn-producing yarn is an undrawn yarn (UDY). Here, the undrawn yarn refers to a yarn that is in the form of a fiber, but has a low degree of molecular chain orientation, and can be easily stretched 3 to 4 times as it is and does not return to its original state.
The extrusion speed at the time of producing the undrawn yarn is not particularly limited and may be appropriately selected depending on the amount of the resin composition, the nozzle diameter, etc., but is usually about 2,000 m / min or less. Of extrusion speed (also called spinning speed).

-Cooling-
There is no restriction | limiting in particular as the method of cooling, According to the objective, it can select suitably, For example, the method of cooling with cooling air, the method of letting the water stored in the water tank pass, etc. are mentioned.
There is no restriction | limiting in particular as said cooling temperature (an air temperature, water temperature, etc.), Although it can select suitably according to annealing temperature, annealing period, etc., 5 to 60 degreeC is preferable and 5 to 50 degreeC is more. 5 to 30 ° C is more preferable, and 10 to 20 ° C is particularly preferable. When the cooling temperature is less than 5 ° C, the crystallite size of the (010) plane included in the void-containing yarn-producing yarn may be too small to produce a void-containing yarn, which exceeds 60 ° C. Then, the crystallite size of the (010) plane becomes too large, and may be cut during stretching in the cavity forming step described later.

-Winding method-
There is no restriction | limiting in particular as said winding method, According to the objective, it can select suitably, For example, the method etc. which wind up with a roller are mentioned.

  There is no particular limitation on the winding speed (also referred to as “winding speed”) of the void-containing yarn-producing yarn (hereinafter sometimes referred to as “undrawn yarn”), and it is appropriately selected according to the purpose. However, 5 m / min to 1,000 m / min is preferable, 20 m / min to 500 m / min is more preferable, and 25 m / min to 200 m / min is particularly preferable. When the winding speed is less than 5 m / min, the extruded yarn is likely to meander, and the void-containing yarn manufacturing yarn is likely to be uneven. When it exceeds 1,000 m / min, stress may occur. May be cut off.

<<< Various yarn for producing void-containing yarn >>>
-(010) plane crystallite size-
The crystallite size of the (010) plane contained in the void-containing yarn-manufacturing yarn obtained in the void-containing yarn-producing yarn forming step is usually less than 2 nm. Therefore, even if it is stretched as it is, the crystallite size of the (010) plane is too small, and when producing a void-containing yarn, sufficient metal-like gloss and high reflectance cannot be obtained even if it is stretched.
The crystallite size of the (010) plane can be measured by, for example, X-ray diffraction.

-Crystallinity-
The degree of crystallinity of the void-containing yarn-producing yarn obtained in the void-containing yarn-producing yarn forming step is usually less than 5%. Accordingly, even if the film is stretched as it is, sufficient metal-like gloss and high reflectance cannot be obtained.
The crystallinity can be measured by, for example, a refractive index method, an infrared spectroscopy method, an X-ray diffraction method, a hydrometer or a density gradient tube method.

-Average diameter-
There is no restriction | limiting in particular as an average diameter of the said yarn for void containing thread | yarn manufacture, Although it can select suitably according to the objective, 10 micrometers-500 micrometers are preferable, and 30 micrometers-200 micrometers are more preferable. When the average diameter is less than 10 μm, sufficient voids may not be expressed inside the void-containing yarn after stretching. When the average diameter exceeds 500 μm, stretching tension becomes high and stretching becomes difficult. The contained yarn may be difficult to reduce in diameter sufficiently.
Here, when the void-containing yarn-producing yarn is a circular shape, the average diameter is the average of the maximum diameters in a cross section perpendicular to the extrusion direction of the resin when producing the void-containing yarn-producing yarn. In other words, when the void-containing yarn-producing yarn is an irregular shape, it means the length of the longest portion in the cross section perpendicular to the extrusion direction of the resin when the void-containing yarn-producing yarn is produced.
The average diameter can be measured by, for example, a photograph of a cross-sectional SEM after embedding the void-containing yarn-producing yarn with an epoxy resin and cutting with a razor or a microtome.

<Process for forming yarn for producing aged void-containing yarn>
<< Crystal Size Aging Method >>
The aging void-containing yarn manufacturing strand forming step is a step of aging the crystallite size contained in the void-containing yarn manufacturing strand formed in the void-containing yarn manufacturing strand forming step. In the present invention, aging may be referred to as annealing.
The method for annealing the crystallite size is not particularly limited as long as the crystallite size of the (010) plane of less than 2 nm in the void-containing yarn manufacturing yarn can be aged to 2 nm to 5 nm. Depending on the situation, it can be selected appropriately, but a method of allowing the void-containing yarn-producing yarn to stand at a constant temperature for a fixed time is preferable.

  There is no restriction | limiting in particular as said annealing time, Although it can select suitably according to annealing temperature etc., 1 hour-90 days are preferable. When the annealing time is less than 1 hour, the aging of the void-containing yarn-producing yarn is insufficient, and the crystallite size on the (010) plane does not become 2 nm to 5 nm. Even if sufficient metal-like luster and high reflectance cannot be obtained, the crystallite size of the (010) plane exceeds 5 nm after 90 days, and in the cavity forming step described later, However, sufficient metal-like gloss and high reflectivity cannot be obtained, and when drawn, cutting tends to occur, and void-containing yarns cannot be produced stably.

  There is no restriction | limiting in particular as said annealing temperature, Although it can select suitably according to the objective, 5 to 45 degreeC is preferable. When the annealing temperature is less than 5 ° C., it takes too much time until the crystallite size of the (010) plane becomes 2 nm or more, and the production efficiency is poor, or the aging of crystal nuclei takes a long time. Hydrolysis or the like may occur, and a desired void-containing yarn may not be obtained even if it is stretched. Further, when the annealing temperature exceeds 45 ° C., the crystallite size of the (010) plane exceeds 5 nm, and sufficient metal-like gloss and high reflectance cannot be obtained even if it is stretched in the cavity forming step described later. In addition, when it is stretched, cutting tends to occur, and the void-containing yarn cannot be produced stably.

  Among the annealing time and the annealing temperature, when the annealing temperature is 5 ° C. or more and 15 ° C. or less (hereinafter sometimes referred to as “low temperature condition”), the annealing time is preferably at least 3 days, and 7 days to 90 days is more preferable, and 10 days to 60 days is particularly preferable. When the annealing time is less than 3 days in the low temperature region, the void-containing yarn-producing yarn is not sufficiently ripened, and the crystallite size on the (010) plane does not become 2 nm to 5 nm. In the process, sufficient metal-like gloss and high reflectivity may not be obtained even if stretched. If it exceeds 90 days, the crystallite size of the (010) plane exceeds 5 nm, and a sufficient metal-like luster and high reflectance cannot be obtained even if it is stretched in the cavity forming step described later, or if it is stretched, it is cut. Is likely to occur, and the void-containing yarn cannot be produced stably.

  When the annealing temperature exceeds 15 ° C. and is 25 ° C. or less (hereinafter sometimes referred to as “medium temperature condition”), the annealing time is preferably at least 12 hours, more preferably 12 hours to 90 days, and more preferably 3 days to 30 days. Days are particularly preferred. When the annealing time is less than 12 hours in the intermediate temperature region, the void-containing yarn-producing yarn is not sufficiently ripened, and the crystallite size on the (010) plane does not become 2 nm to 5 nm. In the process, sufficient metal-like gloss and high reflectivity may not be obtained even if stretched. If it exceeds 90 days, the crystallite size of the (010) plane exceeds 5 nm, and a sufficient metal-like luster and high reflectance cannot be obtained even if it is stretched in the cavity forming step described later, or if it is stretched, it is cut. Is likely to occur, and the void-containing yarn cannot be produced stably.

  When the annealing temperature is more than 25 ° C. and 45 ° C. or less (hereinafter sometimes referred to as “high temperature condition”), the annealing time is preferably at least 1 hour, more preferably 1 hour to 24 hours, more preferably 2 hours to 12 hours. Time is particularly preferred. When the annealing time is less than 1 hour in the high-temperature region, the crystallite size on the (010) plane varies greatly among the plurality of crystal nuclei inside the void-containing yarn-producing strand, and the void-containing yarn is stably produced. There are things you can't do. In addition, if the annealing time exceeds 24 hours, the crystallite size of the (010) plane exceeds 5 nm, and sufficient metal-like gloss and high reflectance cannot be obtained even if it is stretched in the cavity forming step described later. In addition, when stretched, cutting tends to occur, and void-containing yarns cannot be produced stably.

<<< Aged yarn for producing aging void-containing yarn >>>
-Crystallite size-
The crystallite size of the crystal plane of the (010) plane of the crystal nucleus included in the ripening void-containing yarn-producing yarn is 2 nm to 5 nm, preferably 2.1 nm to 4 nm, and preferably 2.5 nm to 4 nm. Is particularly preferred. When the crystallite size of the crystal plane of the (010) plane is less than 2 nm, the crystallite size is too small, and when producing a void-containing yarn, sufficient metal-like gloss and high reflectivity are obtained even when drawn. When it exceeds 5 nm, the crystallite size is too large, and when producing a void-containing yarn, cutting tends to occur due to stretching, and the void-containing yarn cannot be stably produced. Sometimes.
The crystallite size of the crystal plane of the (010) plane can be measured by, for example, X-ray diffraction.

-Crystallinity-
There is no restriction | limiting in particular as a crystallinity degree of the said aging void containing thread | yarn for yarn manufacture, Although it can select suitably according to the objective, 5%-15% are preferable, 5%-12% are more preferable, 7% to 10% is particularly preferable. When the degree of crystallinity is less than 5%, it may not be possible to obtain a sufficient metal-like gloss or high reflectance even when stretched when producing a void-containing yarn. When the containing yarn is produced, if it is stretched, cutting tends to occur, and the void-containing yarn cannot be produced stably.
The crystallinity can be measured by, for example, a refractive index method, an infrared spectroscopy method, an X-ray diffraction method, a hydrometer or a density gradient tube method.

-Reflectance-
The reflectance (%) of the aging void-containing yarn-producing yarn is not particularly limited and may be appropriately selected depending on the intended purpose. However, the reflectance is usually not high, and is 0.1% to 10%. %.
The reflectance can be measured by, for example, a spectrophotometer or an integrating sphere.
The yarn for producing the aged void-containing yarn has a low reflectance (%), but by drawing it into a void-containing yarn, it has a metallic luster and a high reflectance (%). Thus, a void-containing yarn excellent in aesthetics and design can be obtained.

<Cavity formation process>
In the cavity forming step, the aging void-containing yarn manufacturing yarn obtained in the aging void-containing yarn manufacturing yarn forming step is stretched to be independent inside the aging void-containing yarn manufacturing yarn. This is a step of forming void-containing yarns that form cavities and have a metallic luster.
The yarn forming process for producing the ripened void-containing yarn and the cavity formation may be performed independently or may be performed continuously.

<< Cavity formation method >>
There is no restriction | limiting in particular as a method of extending | stretching the said aging void containing thread | yarn for yarn manufacture, According to the objective, it can select suitably, For example, although uniaxial stretching is mentioned, it manufactures in any extending | stretching method. Sometimes, it is preferable that longitudinal stretching is performed along the flowing direction of the aging void-containing yarn manufacturing yarn, and it is more preferable that the aging void-containing yarn manufacturing yarn is stretched so that necking is expressed.
Here, the necking means a constriction-like deformation that occurs at the time of drawing of an aging void-containing yarn production yarn that is an undrawn raw yarn (Polymer Engineering Lecture 6 Edited by Plastics Society of Polymer Science, Jijin Shoin) Issue, see the first edition issued on April 25, 1966). In addition, a phenomenon in which, during the drawing, the ripened void-containing yarn-producing yarn is deformed while being constricted and the cross-section is sharply reduced at the constricted portion is defined as “necking has occurred”.

FIG. 4 is a diagram illustrating an example of a stretching method. As shown in FIG. 4, the aging void-containing yarn manufacturing yarn 5 is inserted into a heating furnace 30 adjusted to, for example, 25 ° C. to 150 ° C. The void-containing yarn 43 having a cavity is produced by stretching and giving necking. In some cases, the same void-containing yarn 43 can be produced simply by heating the nip roll 41 (25 ° C. to 150 ° C.) except for the heating furnace 30. In FIG. 4, 31 represents an annealing furnace, and 32 represents a winding device.
Specifically, the void-containing yarn 43 of the present invention is formed by drawing the aging void-containing yarn-producing yarn 5 (undrawn yarn) and forming a cavity having a major axis in the drawing direction therein. Is obtained.

The reason why the cavities are formed by stretching is that the polymer having at least one crystallinity constituting the mature void-containing yarn-producing yarn has microcrystals that are difficult to stretch, and the microscopic crystals that are difficult to stretch during stretching. By being stretch-stretched in such a way that the non-crystallized amorphous resin between the crystal and other hard-to-stretch microcrystals is torn off at the interface with the microcrystalline phase or inside the amorphous phase. It is considered that this serves as a cavity formation source to form a cavity.
Such void formation by stretching is possible not only when there is only one kind of crystalline polymer but also when two or more kinds of crystalline polymers are blended or copolymerized. is there.

Generally, in stretching, the number of stretching stages and the stretching speed can be adjusted by the combination of rolls and the speed difference between the rolls.
The number of stages of the longitudinal stretching is not particularly limited as long as it is one or more, and can be appropriately selected according to the purpose.

  In particular, recently, it has been studied to further reduce the diameter of the yarn in order to give the yarn functionality, but in order to obtain a void-containing yarn having a further reduced diameter, the fiber structure is not changed. It is also possible to adopt a fluid stretching process or the like that makes the diameter only ultrafine.

-Stretching speed-
The stretching speed of the stretching is not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected according to the purpose, but is preferably 10 m / min to 2,000 m / min, preferably 50 m / min to 1,000 m / min is more preferable, and 100 m / min to 500 m / min is particularly preferable. When the stretching speed is less than 10 m / min, sufficient necking is unlikely to occur, and the formation of voids is not uniform, resulting in uneven thickness and uneven metallic luster. When the drawing speed exceeds 2,000 m / min, the yarn is liable to break, the yield is lowered, and the equipment becomes complicated and costly to maintain handling properties.
On the other hand, when the stretching speed is 10 m / min to 2,000 m / min, it is preferable in that sufficient necking is easily developed. In addition, the yarn is not easily broken, and uniform stretching is easy. In particular, it is preferable in that a large-scale stretching apparatus for high-speed stretching is not required and the cost can be reduced.
More specifically, the stretching speed in the case of one-stage stretching is preferably 100 m / min to 2,000 m / min, more preferably 50 m / min to 100 m / min, and particularly preferably 100 m / min to 500 m / min. .

-Stretching temperature-
The temperature during stretching is not particularly limited and can be appropriately selected according to the purpose.
When the stretching temperature is T (° C) and the glass transition temperature is Tg (° C),
(Tg-30) ≦ T ≦ (Tg + 50)
It is preferable to stretch at a stretching temperature T (° C.) in the range indicated by
(Tg-25) ≦ T ≦ (Tg + 45)
It is more preferable to stretch at a stretching temperature T (° C.) in the range indicated by
(Tg−20) ≦ T ≦ (Tg + 40)
More preferably, the film is stretched at a stretching temperature T (° C.) in the range indicated by.

In general, the higher the stretching temperature (° C.), the lower the stretching tension, and the easier it can be stretched. However, when the stretching temperature (° C.) is {glass transition temperature (Tg) +50} ° C. or less, cavities are formed. This is preferable in that the volume ratio is high and the aspect ratio tends to be in a preferable range. Moreover, it is preferable that the stretching temperature (° C.) is {glass transition temperature (Tg) −30} ° C. or higher in that a cavity is sufficiently developed.
Here, the stretching temperature T (° C.) can be measured with a non-contact thermometer. The glass transition temperature Tg (° C.) can be measured by a differential thermal analyzer (DSC).

<Other processes>
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a shape stabilization process, a coating layer formation process, etc. are mentioned.

<< Shape stabilization process >>
The shape stabilization step is a step of stabilizing the shape of the void-containing yarn after stretching.
In the shape stabilization step, the method for stabilizing the shape of the void-containing yarn is not particularly limited and can be appropriately selected according to the purpose. For example, the void-containing yarn after stretching is further heated. And a method of applying thermal tension to the void-containing yarn after stretching.

<< Coating layer formation process >>
The coating layer forming step is a step of forming a coating layer on the surface of the void-containing yarn after stretching.
The material of the coating layer is not particularly limited as long as the effects of the invention are not impaired, and can be appropriately selected according to the purpose. Examples thereof include hydrophobic polymers such as polyolefins and fluororesins. . Thereby, durability, especially water resistance, hydrolysis resistance, tensile elastic modulus, and bendability can be improved.
Moreover, you may use dye as the said coating layer. For example, by coating the void-containing yarn with a dye such as black or blue, a void-containing yarn such as metallic black or metallic blue can be obtained, which is preferable in terms of widening the range of uses of the void-containing yarn.
There is no restriction | limiting in particular as thickness of the said coating layer, According to the objective, it can select suitably, For example, 3-30% of the radius in the cross section (a resin part and a cavity part are included) of the said void containing thread | yarn preferable. When the thickness of the coating layer is less than 3% of the radius in the cross section of the void-containing yarn, mechanical characteristics may not be sufficiently imparted, and when the thickness exceeds 30% of the radius in the cross section of the void-containing yarn, The suppleness and feel as a fiber may be insufficient, and productivity may be reduced.

<Void-containing yarn>
The void-containing yarn produced by the void-containing yarn production method of the present invention is a void-containing yarn having an independent cavity inside. Here, the cavity means a vacuum domain or a gas phase domain existing in the void-containing yarn.
An example of a cross-sectional view of the void-containing yarn is shown in FIGS. 1A and 1B. FIG. 1A is a cross-sectional view of the void-containing yarn when the shape of the hole in the nozzle opening is circular, and FIG. 1B is the cross-sectional view of the void-containing yarn when the shape of the hole in the nozzle opening is irregular. It is sectional drawing. As shown in FIGS. 1A and 1B, the void-containing yarn 43 has a cavity 60 inside. The void-containing yarn may have a coating layer 12 as shown in FIGS. 2B and 3B.

<< Cavity >>
-Aspect ratio-
2A to 2C are diagrams for explaining an aspect ratio in a case where the void-containing yarn is circular, and FIG. 2A is a perspective view of the void-containing yarn, and FIG. 2B is a perspective view of FIG. FIG. 2C is a cross-sectional view of the void-containing yarn in FIG. 2A, and FIG. 2C is a cross-sectional view of the void-containing yarn in FIG.
3A to 3C are diagrams for explaining an aspect ratio when the void-containing yarn is atypical, and FIG. 3A is a perspective view of the void-containing yarn, and FIG. 3B is a view in FIG. FIG. 3C is a cross-sectional view taken along line AA ′ of the void-containing yarn, and FIG. 3C is a cross-sectional view taken along line BB ′ of the void-containing yarn in FIG. 3A.

  The aspect ratio is defined as an average diameter r (μm) of the cavity 60 in a direction (AA ′ cross section) perpendicular to the surface 43a of the void-containing yarn 43 and perpendicular to the orientation direction of the cavity (FIG. 2B). And the average length of the cavities 60 in the orientation direction (BB ′ cross section) of the cavities L (μm) (see FIG. 2C and FIG. 3B). L / r ratio in the case of 3C).

The aspect ratio can be calculated by the following method.
(1) The AA ′ cross section and the BB ′ cross section are each embedded in an epoxy resin, cut with a razor or a microtome, and examined with a scanning electron microscope. (Refer to FIG. 2B and FIG. 3B) is set so that 50 to 100 cavities are included in the frame.
(2) The number of cavities included in the measurement frame is measured, and the number of cavities included in the measurement frame (see FIGS. 2B and 3B) having a cross section perpendicular to the longitudinal stretching direction is parallel to the longitudinal stretching direction. It is assumed that the number of cavities included in a measurement frame having a simple cross section (see FIGS. 2C and 3C) is n.
(3) The maximum diameter (r _i ) of each cavity included in the AA ′ cross section is measured, the average diameter is r (see FIG. 2B and FIG. 3B), and the BB ′ cross section The length (L _i ) of each longest portion of the cavities included in the measurement frame (see FIG. 2C and FIG. 3C) is measured, and the average length is defined as L.
That is, r and L can be expressed by the following formulas (1) and (2), respectively, whereby the aspect ratio L / r can be calculated.
r = (Σr _i ) / m (1)
L = (ΣL _i ) / n Expression (2)

  The aspect ratio is not particularly limited as long as the effect of the present invention is not impaired, and can be appropriately selected according to the purpose, but is preferably 10 or more, more preferably 10 to 100, and further preferably 15 to 100. 20 to 90 are particularly preferred. When the aspect ratio is less than 10, the reflectivity may be lowered, and when it exceeds 100, the mechanical properties may be lowered. When the aspect ratio is 10 to 100, it is advantageous in terms of both performance such as reflection and dynamic characteristics.

  In addition, the orientation direction of the cavity usually indicates a stretching direction. Usually, since longitudinal stretching is performed along the flowing direction of the aging void-containing yarn-producing yarn during production, this longitudinal stretching direction becomes the orientation direction of the cavities.

−Cavity area−
In the void-containing yarn, the cross-sectional area of the void-containing yarn in an arbitrary cross section orthogonal to the length direction (stretching direction) is a (μm ² ), and the cross-sectional area of the cavity in the cross section is A (μm ^2). ), The average of these ratios (A / a) is preferably 0.05 or more and 0.4 or less.
Each cross-sectional area in the cross section can be measured by, for example, an image of an optical microscope or an electron microscope.

  The void-containing yarn preferably has a product of an average number P of cavities in the thickness direction and a refractive index difference ΔN between the resin part having a crystallinity and the cavities, preferably 2 or more, more preferably 2.5 or more. 3 or more are more preferable. If the product of ΔN and P is less than 2, the reflectance may decrease.

Here, the number of cavities in the thickness direction is a plane that includes a direction perpendicular to the surface 43a of the void-containing yarn 43 and perpendicular to the orientation direction of the cavities (AA in FIGS. 2A and 3A). In the 'cross section, that is, the cross section in the thickness direction ", it means the number of cavities 60 included in the thickness direction.
The average number P of cavities in the thickness direction in the void-containing yarn is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 or more, more preferably 10 or more, and 15 The above is more preferable.
The number of cavities in the thickness direction can be measured by, for example, images of an optical microscope or an electron microscope. On these images, a plurality of straight lines are drawn in parallel in the thickness direction, The average number P can be obtained by calculating the average value of the number of cavities existing in.

Further, the resin part 61 having crystallinity refers to a part other than the cavity (part made of resin having crystallinity) in the void-containing yarn 43 (shaded part in FIGS. 1A and 1B).
Specifically, the difference in refractive index ΔN between the resin part having crystallinity and the cavity in the void-containing yarn is N1 when the refractive index of the resin part having N1 is N1 and the refractive index of the cavity is N2. It means a value of ΔN (= N1−N2) which is a difference from N2.
The refractive indexes N1 and N2 of the resin part having a crystallinity and the cavity can be measured by, for example, an Abbe refractometer.

  As described above, the void-containing yarn has various excellent characteristics in, for example, metallic luster, reflectivity, concealability, heat insulation, cushioning property, and the like by having the cavity therein. doing. That is, characteristics such as metallic luster, reflectivity, concealing property, heat insulating property, cushioning property, and the like can be adjusted by changing the mode of the void inside the void-containing yarn.

-Average diameter-
There is no restriction | limiting in particular as an average diameter of the said void containing thread | yarn, Although it can select suitably according to the objective, 5 micrometers-200 micrometers are preferable, 5 micrometers-100 micrometers are more preferable, and 5 micrometers-50 micrometers are especially preferable. When the average diameter of the void-containing yarn is less than 5 μm, it may be cut at the time of drawing, or a sufficient cavity may not be vacant, and a sufficient metallic luster and high reflectance may not be obtained. If it is 200 μm or more, the ratio of the cavities is too large, the color becomes worse, and it becomes stiff, so that it may be inferior in texture when further processed and woven. On the other hand, when the average diameter of the void-containing yarn is within the particularly preferable range, it is advantageous in that a sufficient metallic luster and high reflectance can be obtained.
The average diameter of the void-containing yarn means the average of the maximum diameter in a cross section in the direction orthogonal to the length direction of the void-containing yarn when the void-containing yarn is circular, and the void-containing yarn is atypical. In this case, it means the length of the longest portion in the cross section in the direction orthogonal to the length direction of the void-containing yarn.
Here, for example, after the void-containing yarn is cut with a razor or a microtome, the diameter of the void-containing yarn can be measured by a photograph of a cross-sectional SEM.

-Reflectance-
The reflectance (%) of the void-containing yarn is literally the reflectivity when the void-containing yarn is woven or knitted into a cloth shape.
The reflectance is preferably 30% or more, more preferably 50% or more, and particularly preferably 60% or more. If the reflectance is less than 30%, the aesthetics and design of the void-containing yarn may be deteriorated. In addition, since the one where a reflectance is higher is excellent in the aesthetics and design nature by metal-like luster, the upper limit has no critical significance.
The reflectance can be measured by, for example, a spectrophotometer or an integrating sphere.

-Density-
The density of the void-containing yarn is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1.20 g / cm ³ or ^{less, 0.5g / cm 3 ~1.05g / cm} 3 is More preferred.
As a method for measuring the density, for example, when the density is 1.05 g / cm ³ or more, a 5 mm void-containing yarn can be measured by a density gradient tube method. When the density is less than 1.05 g / cm ^{3, in} the method described in JIS K6920, for example, a weighted yarn-containing pycnometer (25 mL) is accurately weighed with an electronic balance and weighing about 1 g of void-containing yarn. can do.

-Yield rate-
The yield of the void-containing yarn having a metallic luster obtained by the method for producing a void-containing yarn of the present invention is set according to the business purpose, profitability, etc., and is not particularly limited.
The yield is, for example, the length remaining after sampling the void-containing yarn over 100 m after the elapse of 5 seconds from the start of stretching, and excising the transparent to milky white portion by visual inspection with respect to the entire length. The length (m) is (A) and can be calculated from the following calculation formula (I).
Yield of void-containing yarn (%) = (A) / 100 × 100 Formula (I)

<Application>
The method for producing the void-containing yarn further comprises ripening a crystal nucleus contained in the void-containing yarn production yarn, producing an aged void-containing yarn production yarn having a desired crystallite size, and producing the aged void-containing yarn. Since the void-containing yarn is produced using the yarn for use, the void-containing yarn can be drawn uniformly, and therefore, a void-containing yarn excellent in metal-like gloss and high aesthetics and design with high reflectivity can be produced. Since the void-containing yarn is light and excellent in heat insulation and light shielding properties, it can be suitably used for various applications such as clothing, building materials, medical materials, electronic equipment members, and electric vehicle members.

  EXAMPLES The present invention will be specifically described below with reference to examples of the present invention, but the present invention is not limited to these examples.

Example 1
<Preparation of void-containing yarn production yarn (undrawn yarn)>
-Raw yarn forming process for producing void-containing yarn-
A polybutylene terephthalate (PBT) resin (manufactured by Wintech Polymer Co., Ltd.) having an intrinsic viscosity (IV) of 0.72 and a glass transition temperature (Tg) of 37 ° C. is melt-spun (single-screw melt extruder having a screw diameter of 35 mmφ (Co., Ltd.) The yarn for producing the void-containing yarn of Example 1 was produced by melting at 255 ° C. using Chubu Chemical Machinery Co., Ltd., and cooling and solidifying through water. Was wound at a winding speed of 35 m / min, and the shape of the hole in the nozzle opening of the melt spinning machine was substantially circular, and the water temperature for solidifying the void-containing yarn-producing yarn was 15 ° C. Set to.

<Evaluation of yarn for producing void-containing yarn>
The crystallite size and crystallinity of the crystal plane of the (010) plane of the void-containing yarn manufacturing yarn were measured by the following method. The results are shown in Table 3.

-Measurement of crystallite size of crystal plane of (010) plane inside void-containing yarn manufacturing yarn-
Using an X-ray diffractometer (RINT-TTR III, manufactured by Rigaku Corporation), the measurement was performed by arranging the yarns on a glass sample holder so as to have a width of 25 mm. A peak separation between a crystal peak and an amorphous peak (2θ = 21 °) was performed. Using the full width at half maximum of each peak, the crystallite size (nm) of the crystal plane of the (010) plane inside the void-containing yarn manufacturing yarn is obtained from the Scherrer equation (Scherrer coefficient = 0.9). It was.

-Measurement of crystallinity-
The crystallinity (%) of the void-containing yarn-producing yarn was measured by a density gradient tube method using a carbon tetrachloride / heptane mixed solution.

<Production of yarn for producing aging void-containing yarn>
-Raw yarn forming process for producing aging void-containing yarn-
The void-containing yarn-producing yarn was annealed at 10 ° C. for 3 days to age the crystal nuclei contained in the void-containing yarn-producing yarn, thereby producing an aged void-containing yarn-producing yarn.
The crystallite size and the degree of crystallinity of the crystal plane of the (010) plane contained in the yarn for producing an aged void-containing yarn were measured by the same method as described above.

<Production of void-containing yarn>
-Cavity formation process-
Stretching of the yarn for producing an aging void-containing yarn was performed using two drawing rolls and a plate heater installed therebetween. That is, the aging void-containing yarn production yarn was uniaxially stretched (magnification: 5.6 times) at a low speed nip roller speed of 35 m / min and a high speed nip roller speed of 195 m / min in a heated atmosphere at 39 ° C. At this time, the aging void-containing yarn-producing yarn was drawn while exhibiting necking. This produced the void-containing yarn of Example 1.
The yield of void-containing yarn was calculated from the following calculation formula (I). The results are shown in Table 3.
Yield of void-containing yarn (%) = (A) / 100 × 100 Formula (I)
However, in the above formula (I), (A) is a sample of void-containing yarn over 100 m after 5 seconds after neck stretching has started, and the entire length is transparent to milky white by visual inspection. The length (m) remaining after excising the part is shown.

<Evaluation of void-containing yarn>
The average diameter, reflectance, and aspect ratio of the void-containing yarn were measured by the following method. In addition, the sensory evaluation of the metallic luster of the void-containing yarn was performed by the method described below. The results are shown in Table 3.

-Measurement of average diameter of void-containing yarn-
The average diameter (μm) of the void-containing yarn was obtained by measuring the diameter with a photograph of the cross-section SEM after cutting a section perpendicular to the drawing direction of the void-containing yarn with a razor and calculating the average value of the maximum diameter.

-Measurement of reflectance-
The light reflectance (%) of the void-containing yarn was measured at a wavelength of 550 nm using a spectrophotometer (V-570, manufactured by JASCO Corporation) and an integrating sphere (ILN-472, manufactured by JASCO Corporation).

-Measurement of aspect ratio-
A cross section perpendicular to the surface of the void-containing yarn and perpendicular to the longitudinal stretching direction (see FIG. 2B), and a cross section perpendicular to the surface of the void-containing yarn and parallel to the longitudinal stretching direction (see FIG. 2C). Were cut with a razor and examined with a scanning electron microscope at an appropriate magnification of 300 to 3,000, and a measurement frame (see FIG. 2B) was set in each of the cross-sectional photographs. This measurement frame was set so that 50 to 100 cavities were included in the measurement frame.
Next, the number of cavities included in the measurement frame is measured, and the number of cavities included in the measurement frame having a cross section perpendicular to the longitudinal stretching direction (see FIG. 2B) is m and the cross section parallel to the longitudinal stretching direction. The number of cavities included in the measurement frame (see FIG. 2C) was n.
Then, the longitudinal measurement frame of the cross-section perpendicular to the stretching direction to measure the maximum diameter of each one of the cavities included in (see FIG. 2B) (r _i), and the average diameter of the r. Further, the length (L _i ) of each longest portion of the cavities included in the measurement frame (see FIG. 2C) having a cross section parallel to the longitudinal stretching direction was measured, and the average length was defined as L.
That is, r and L can be represented by the following formulas (1) and (2), respectively.
r = (Σr _i ) / m (1)
L = (ΣL _i ) / n Expression (2)
Then, L / r was calculated as an aspect ratio.

-Sensory evaluation of metallic luster-
Twenty void-containing yarns after stretching were collected, and the samples that were closely arranged on the black plate and attached were used as evaluation samples. On the other hand, 20 AL wires (φ0.12 mm) were prepared as a reference sample in the same manner as the void-containing yarns, which were closely arranged and pasted on a black plate.
These samples were compared visually by a panel of metal-like glossy yarns under a white fluorescent lamp. At this time, the illuminance on the sample surface was changed from 1,300 Lx to 1,500 Lx. The illuminance was measured with a pocket illuminometer (ANA-F9, manufactured by Tokyo Photoelectric Co., Ltd.).
The number of panelists who judged that the metal-like gloss of the void-containing yarn was equal to or higher than that of the reference sample was scored (1-5). That is, the higher the score, the better the metallic luster. The results are shown in Table 3. Table 3 also shows the appearance and state at this time.

(Examples 2-11, 13-20, Comparative Examples 2, 3, 5)
Except for using the yarn for producing void-containing yarn produced in Example 1 and changing the conditions in the yarn forming step for producing mature void-containing yarn of Example 1 to the conditions shown in Table 1 and Table 2, respectively. A void-containing yarn was produced in the same manner as in Example 1. About each aged void containing thread | yarn for manufacturing yarn, each aging void containing thread | yarn for producing yarn of Examples 2-11, 13-20, and Comparative Examples 2, 3, and 5 is the same method as Example 1. The crystallite size and crystallinity of the crystal plane of the (010) plane to be included were measured. The results are shown in Table 3.

  Next, in the cavity forming step of Example 1, each of the yarns produced in Examples 2 to 11, 13 to 20 and Comparative Examples 2, 3, and 5 was used instead of the aging void-containing yarn production yarn of Example 1. A void-containing yarn was produced in the same manner as in Example 1 except that the yarn for producing an aged void-containing yarn was used. For each of the void-containing yarns of Examples 2 to 11, 13 to 20, and Comparative Examples 2, 3, and 5, the void-containing yarn yield was calculated in the same manner as in Example 1, and the average diameter of the void-containing yarns , Reflectance, and aspect ratio were measured. The results are shown in Table 3.

(Example 12)
<Preparation of void-containing yarn production yarn (undrawn yarn)>
-Raw yarn forming process for producing void-containing yarn-
Polyethylene terephthalate (PET) (manufactured by FUJIFILM Corporation) having an intrinsic viscosity (IV) of 0.76 and a glass transition temperature (Tg) of 75 ° C. is melt melt spinning machine (single screw melt extruder having a screw diameter of 35 mmφ (Chubu Chemical Co., Ltd.) Machined) was melted at 285 ° C. and cooled and solidified through water to produce a void-containing yarn-producing yarn of Example 12. In addition, the void-containing yarn-producing yarn after cooling was Winding was performed at a winding speed of 35 m / min, and the shape of the hole at the nozzle opening of the melt spinning machine was substantially circular, and the water temperature for solidifying the void-containing yarn manufacturing yarn was set to 25 ° C. did.
With respect to the crystal nuclei included in the void-containing yarn-producing yarn of Example 12, the crystallite size and crystallinity of the (010) plane were measured in the same manner as in Example 1. The results are shown in Table 3.

<Production of yarn for producing aging void-containing yarn>
-Raw yarn forming process for producing aging void-containing yarn-
The void-containing yarn-producing yarn was allowed to stand at 25 ° C. for 7 days to age the crystal nuclei contained in the void-containing yarn-producing yarn, thereby producing an aged void-containing yarn-producing yarn. .
The crystallite size and crystallinity of the crystal plane of the (010) plane contained in the aging void-containing yarn-producing yarn were measured in the same manner as in Example 1. The results are shown in Table 3.

<Production of void-containing yarn>
-Cavity formation process-
Stretching of the yarn for producing an aging void-containing yarn was performed using two drawing rolls and a plate heater installed therebetween. That is, the aging void-containing yarn production yarn was uniaxially stretched (magnification: 5.8 times) at a low speed nip roller speed of 25 m / min and a high speed nip roller speed of 145 m / min in a heated atmosphere at 80 ° C. At this time, the aging void-containing yarn-producing yarn was drawn while exhibiting necking. This produced the void-containing yarn of Example 12.
For the void-containing yarn of Example 12, the yield of the void-containing yarn was calculated in the same manner as in Example 1, and the average diameter, reflectance, and aspect ratio of the void-containing yarn were measured. The results are shown in Table 3.

(Comparative Example 1)
In Example 1, a void-containing yarn was produced in the same manner as in Example 1 except that the raw yarn forming step for producing an aged void-containing yarn was not performed. With respect to the void-containing yarn manufacturing yarn of Comparative Example 1, the crystallite size and crystallinity of the crystal plane of the (010) plane contained in the void-containing yarn manufacturing yarn were measured in the same manner as in Example 1. . The results are shown in Table 3.

  Next, in the void forming step of Example 1, Example 1 was used except that the void-containing yarn-producing yarn produced in Comparative Example 1 was used in place of the matured void-containing yarn-producing yarn of Example 1. A void-containing yarn was prepared in the same manner as described above. For the void-containing yarn of Comparative Example 1, the yield of the void-containing yarn was calculated in the same manner as in Example 1, and the average diameter, reflectance, and aspect ratio of the void-containing yarn were measured. The results are shown in Table 3.

(Comparative Example 4)
In Example 12, a void-containing yarn was produced in the same manner as in Example 12 except that the yarn forming step for producing the matured void-containing yarn was not performed. For the void-containing yarn-producing yarn of Comparative Example 4, the crystallite size and crystallinity of the crystal plane of the (010) plane contained in the void-containing yarn-producing yarn were measured in the same manner as in Example 1. . The results are shown in Table 3.

  Next, in the cavity forming step of Example 12, Example 12 was used except that the void-containing yarn-producing yarn produced in Comparative Example 4 was used in place of the mature void-containing yarn-producing yarn of Example 12. A void-containing yarn was prepared in the same manner as described above. For the void-containing yarn of Comparative Example 4, the yield of the void-containing yarn was calculated in the same manner as in Example 12, and the average diameter, reflectance, and aspect ratio of the void-containing yarn were measured. The results are shown in Table 3.

Tables 1 and 2 below collectively show the void-containing yarn production yarns of Examples 1 to 20 and Comparative Examples 1 to 5 and the production conditions of the void-containing yarns. The evaluation results of Examples 1 to 20 and Comparative Examples 1 to 5 are shown in Table 3 below.
FIG. 5 plots the relationship between the annealing time and the crystallite size, the relationship between the annealing time and the crystallinity, and the relationship between the annealing time and the reflectance for the low temperature condition, the medium temperature condition, and the high temperature condition, respectively. A scatter diagram is shown. In FIG. 5, the examples of the same annealing time and the comparative examples in the low temperature condition, medium temperature condition, and high temperature condition are the average values of crystallite size, crystallinity, and reflectance at the annealing time. The values calculated for each were plotted.
FIG. 6 is a distribution plotting the relationship between the yield of void-containing yarns of Examples 1 to 20 and Comparative Examples 1 to 5 and the crystallite size of the (010) plane of the crystal nucleus of the yarn for producing void-containing yarns. The figure is shown.
FIG. 7 shows a scatter diagram in which the relationship between the yield of the void-containing yarns of Examples 1 to 20 and Comparative Examples 1 to 5 and the crystallinity of the void-containing yarn-producing yarn is plotted.

  From the results shown in Table 3 and FIGS. 5 to 7, the low temperature condition (5 ° C. to 15 ° C.) is at least 3 days, and the medium temperature condition (over 15 ° C. to 25 ° C.) is at least 12 hours. ℃ or lower), by annealing for at least 1 hour, the crystallite size of the crystal plane of the (010) plane of the crystal nucleus included in the void-containing yarn-producing yarn is aged to a range of 2 nm to 5 nm, It was found that a void-containing yarn having gloss and high reflectivity and excellent aesthetics and design can be produced stably and efficiently. In Examples 1, 2, and 3, unevenness was observed in the metallic luster. In Example 14, the crystallite size on the (010) plane varied greatly, and the void-containing yarn could not be produced stably.

  In the method for producing a void-containing yarn of the present invention, the fine crystal nuclei contained in the void-containing yarn-producing yarn can be aged to a desired crystallite size of the (010) plane, and the aged Since a void-containing yarn is produced using a yarn for producing an aged void-containing yarn that encloses a crystal nucleus, the void-containing yarn can be drawn uniformly, so that it has a metallic luster, high reflectivity, aesthetics and design. A void-containing yarn having excellent properties can be produced. The void-containing yarn contains voids that do not communicate with each other, and is light and excellent in heat insulation and light-shielding properties. Therefore, it is preferably used for various applications such as clothing, building materials, medical materials, electronic equipment members, and electric vehicle members. Can do.

DESCRIPTION OF SYMBOLS 5 Yarn for aging void-containing yarn production 12 Coating layer 30 Heating furnace 31 Annealing treatment furnace 32 Winding device 41 Nip roll 42 Nip roll 43 Void containing thread 43a Surface of void containing thread 60 Cavity 61 Resin section

Claims (8)

For void-containing yarn production, a resin melt-extruded in the form of a thread from a nozzle is passed through water, and a void-containing yarn production strand is formed in which crystal nuclei having a crystallite size of (010) plane of less than 2 nm are included. A yarn forming process;
Aged void-containing yarn for aging the crystal nucleus until the crystallite size of the (010) plane crystal face in the void-containing yarn-producing yarn is 2 nm to 5 nm to form an aged void-containing yarn-producing yarn. A production yarn forming process;
A void forming step of forming an independent cavity inside the aged void-containing yarn-producing yarn by drawing the aged void-containing yarn-producing yarn, Method.   The method for producing a void-containing yarn according to claim 1, wherein the crystal nucleus is aged until the crystallinity of the yarn for producing the void-containing yarn is 5% to 15% in the forming step for producing the matured void-containing yarn.   Any of the conditions in which the yarn forming process for producing the mature void-containing yarn is 5 ° C. or more and 15 ° C. or less for at least 3 days, 15 ° C. or more and 25 ° C. or less for at least 12 hours, and 25 ° C. or more and 45 ° C. or less for at least 1 hour. The method for producing a void-containing yarn according to any one of claims 1 to 2, wherein the yarn is ripened in a step.   The method for producing a void-containing yarn according to any one of claims 1 to 3, wherein the cavity forming step is performed by a necking drawing method.   5. The method for producing a void-containing yarn according to claim 1, wherein the temperature of water is 5 ° C. to 30 ° C. in the yarn forming step for producing the void-containing yarn.   The method for producing a void-containing yarn according to any one of claims 1 to 5, wherein the resin is a crystalline polymer.   L / r ratio when the cavity is oriented in the stretching direction, the average length of the cavity is L (μm), and the average diameter of the cavity in the direction orthogonal to the orientation direction of the cavity is r (μm) The method for producing a void-containing yarn according to any one of claims 1 to 6, wherein is 10 or more.   The method for producing a void-containing yarn according to any one of claims 1 to 7, wherein the reflectance of the void-containing yarn is 50% or more.