TWI580831B - Polyester-based conjugate fiber excellent in heat shielding and color development - Google Patents

Description

Polyester composite fiber excellent in heat insulation and color rendering

This application claims the priority of Japanese Patent Application No. 2012-014682, filed on Jan. 27, 2012, which is incorporated herein by reference in its entirety.

The present invention relates to a polyester-based composite fiber which has heat insulating properties due to high reflectance in a wavelength (800 to 3000 nm) of infrared rays which are easily converted into thermal energy, and has the same degree as conventional polyester fibers. Color rendering.

There are a number of fabrics that are more familiar and more cool. For example, there is a method of cooling the sensation due to the heat insulating effect in the shape of a fiber or a weaving method (Patent Document 1), and a method of reflecting infrared rays coated on a surface of a fiber with a silver-plated cloth ( Patent Document 2) A method in which a wavelength (800 to 3000 nm) of reflected infrared rays of titanium oxide is contained in a core component and a sheath component.

Patent Document 1 discloses a monofilament in which a total of 3% by weight or more of a solar shading substance is contained, and a content of a solar shading substance in a sheath portion is 0.8% by weight or less by using a specific high volume containing the monofilament. Polyester multifilament crimped filaments, which contain a large amount inside the thread The air exerts a heat-insulating effect, and a cool feeling is obtained.

Patent Document 2 describes a fabric which uses a fabric material which is coated with silver-plated fibers on the surface of the fiber and which has infrared reflectivity, and which is used for the temporary construction of a tent, The roofing material and the leisure tent of the top structure reflect the infrared rays of the sun and adjust the temperature inside the building.

Patent Document 3 discloses that titanium oxide having an average particle diameter of 0.8 to 1.8 μm in an amount of 3% by weight or more in the core portion and titanium oxide having an average particle diameter of 0.4 μm or less in the sheath portion of 0.5 to 10% by weight can be used. The reflection is easily converted into the wavelength of the infrared rays of the thermal energy to obtain an insulating effect.

Patent Document 4 discloses a knitted fabric comprising 40% by weight or more of a core-sheath type synthetic fiber and uniformly adhering an infrared ray absorbing agent having a content of inorganic oxide fine particles of 3 to 20 by weight. In the sheath portion in which the content of the core portion and the inorganic oxide fine particles is 2% by weight or less, it is described that the knitted fabric is capable of reflecting visible light and ultraviolet rays by the core-sheath type synthetic fiber, and by attaching the infrared absorbing agent. It can prevent the penetration of infrared rays.

However, in Patent Document 1, in order to increase the volume of the filament, the high alignment undrawn yarn is supplied to the heat treatment machine, and after the overfeed treatment, the step of stretching and false twist processing is required, and the cost is increased.

In Patent Document 2, it is necessary to use a silver plating on a fabric. Since the silver plating step is necessary, the cost is not only high, but also the silver plating is applied to the fabric, which also has the disadvantage of light shielding.

In Patent Document 3, since 0.5 to 10% by weight of titanium oxide is contained in the sheath portion, there is a disadvantage that coloration due to dyeing is lowered.

In Patent Document 4, since the amount of the inorganic oxide fine particles in the core portion is only 3 to 20% by weight, it is apparent from the use of the infrared absorbing agent for the knitted fabric that the infrared ray reflectability of the single core-sheath type synthetic fiber alone is not sufficient.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 8-158186

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-92842

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2011-241530

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-223171

The present invention addresses the problems of the prior art.

An object of the present invention is to provide a core-sheath type composite fiber which not only reflects infrared rays but also has a heat insulating effect, and does not cause color abnormality due to whitening and can vividly develop color.

Another object of the present invention is to provide a core-sheath type composite fiber which is excellent in not only the spinning property but also excellent heat insulating property and color rendering property.

As a result of intensive investigations to solve the above problems, the inventors of the present invention have found that it is recognized that if a solar shading substance is contained, the fiber will be whitened due to the reflectivity of the solar shading substance, and it is impossible to enhance the display. Chromaticity, but if (i) contains a solar shading substance having a specific average particle diameter in the core component, (ii) in the sheath component Containing heat-insulating fine particles having a specific average particle diameter smaller than the core component, and combining (iii) a sheath component having a larger core component, the core component can effectively reflect sunlight, and on the other hand, the sheath component The present invention can be completed not only by improving the heat insulating property but also by maintaining color rendering.

That is, the present invention is a core-sheath type composite fiber comprising a core component (component A) and a sheath component (component B), and the core component contains an average particle diameter of 8% by weight or more and 70% by weight or less of 0.5 μm or less (preferably The thermoplastic polymer of the solar shading substance which is more than 0.1 μm and not more than 0.5 μm, the sheath component has an average particle diameter of 0.1 μm or less and is smaller than the solar shading substance, and is contained in an amount of 0.5% by weight or more and 10% by weight or less. A polyester-based polymer capable of maintaining color-developing heat-insulating fine particles. The mass ratio of the core component to the sheath component is 10:90 to 30:70. The core component may contain more than 20% by weight and 70% by weight or less of the solar shading substance. Preferably, the total moisture content of the entire fiber may be 0.3% or more.

The solar shading substance may be at least one selected from the group consisting of titanium oxide, zinc oxide, and barium sulfate. Further, the heat insulating fine particles may be at least one selected from the group consisting of cerium oxide and barium sulfate.

Further preferably, in the core-sheath type composite fiber, a linear distance from a center point G of the cross section of the fiber to a far point of the outer peripheral portion of the fiber is set to R, and a point G from the center of gravity to the far point of the core component is further When the linear distance is set to r, it can be R/r ≧ 1.8.

Next, the core-sheath type composite fiber may have an average reflectance of 70% or more for infrared rays having a wavelength of 800 to 1200 nm. Further, the L* value may be 16.5 or less.

Further, in the present invention, "the color rendering property can be maintained", The coloring property of the fiber is maintained, and the color rendering property is not substantially reduced. For example, since titanium oxide is used as a matting agent to hinder color development of the fiber, the heat insulating fine particles are not contained. Further, when the color rendering property can be maintained and the function of shielding sunlight is also provided, the solar shading substance and the heat insulating fine particles can be the same type of inorganic compound.

Further, any combination of at least two constituent elements disclosed in the scope of the patent application and/or the specification is included in the invention. In particular, any combination of two or more of the claims recited in the scope of the patent application is also included in the present invention.

In the present invention, in the core-sheath composite fiber, a polyester-based polymer containing heat-insulating fine particles having a specific particle diameter and ratio is used for the sheath component, and a solar light-shielding substance having a specific particle diameter and ratio is contained. The thermoplastic polymer is used for the core component, and has a specific relationship that the sheath component has a large mass ratio with respect to the core component, and the core-sheath type composite fiber has high reflectance at a wavelength which is easily converted into infrared rays of heat energy, and can be obtained. It has a thermal effect and can have the same degree of color development as conventional polyesters.

According to the present invention, since the sheath component has a specific relationship with respect to the core component and the mass ratio is large, the color development property and the spinning property of the fiber can be maintained even if a large amount of the masking substance is mixed into the core component.

Moreover, when the core-sheath type composite fiber has a specific specific moisture content, the heat insulation effect can be improved.

Further, when the core-sheath type composite fiber has a specific sectional shape, the color development of the fiber can be improved.

G‧‧‧ Focus

R‧‧‧ Straight line distance from the center of gravity G to the outer point of the fiber

r‧‧‧Digital distance from the center of gravity G to the core component to the far point

Fig. 1 is a schematic view showing an example of a cross-sectional form of a conjugate fiber of the present invention.

Fig. 2 is a cross-sectional photograph showing an example of a composite cross-sectional form of the fiber of the present invention.

The invention is based on the following description of the preferred embodiments of the drawings and will be more clearly understood. However, the embodiments and the drawings are only used for illustration and description, and should not be used to limit the scope of the invention. The scope of this invention is defined by the scope of the patent application.

[Formation of the Invention]

The core component (component A) of the core-sheath type composite fiber of the present invention is a thermoplastic polymer containing a specific amount of a solar shading substance having an average particle diameter of 0.5 μm or less, and the sheath component (component B) has an average particle diameter of 0.1 μm or less. A polyester-based polymer having an average particle diameter smaller than the above-mentioned solar shading substance and containing a specific amount of heat-insulating fine particles capable of maintaining color development of the fiber, and a mass ratio of the core component to the sheath component is 10:90 to 30: 70.

[core component (component A)]

The thermoplastic polymer containing a solar shading substance (hereinafter sometimes simply referred to as A component polymer) constituting the core component (component A) of the core-sheath type composite fiber of the present invention will be described. Polyamide, polyester, polypropylene, and the like can be used for the A component polymer, that is, the thermoplastic polymer containing the solar shading substance. Among them, based on a high-filling sunlight shielding material, and a high price and versatility, it is preferably polyamine or polyethylene terephthalate. Polyester.

Further, in the present invention, a so-called solar shading substance (preferably an infrared shading substance) must be reflected or penetrated by an infrared wavelength (800 to 3000 nm, especially 800 to 1200 nm) which does not easily convert into thermal energy. And can be highly filled into the fine particles in the thermoplastic polymer. For example, a monomer such as titanium oxide, zinc oxide or barium sulfate and a mixture of these may be mentioned. Particularly preferred is titanium oxide which is used as a matting agent and has high versatility.

Further, in the present invention, by containing 8% by weight or more and 70% by weight or less of the solar light shielding material having an average particle diameter of 0.5 μm or less in the component A polymer, the wavelength of infrared rays which are easily converted into heat energy is efficiently reflected. Therefore, the heat insulation effect is exerted. When the content of the solar shading substance is less than 8% by weight, the wavelength of the infrared ray cannot be efficiently reflected, and a sufficient heat insulating effect cannot be obtained. On the other hand, if the content of the solar shading substance exceeds 70% by weight, not only the spinnability at the time of spinning is extremely deteriorated, but also the color rendering property at the time of dyeing is also lowered. It is preferably 10% by weight or more, more preferably more than 20% by weight. On the other hand, the content of the solar shading substance is preferably 60% by weight or less, and more preferably 50% by weight or less, from the viewpoint of improving the spinning property.

In addition, when the average particle diameter of the solar shading substance is more than 0.5 μm, not only the yarn-making property is lowered, but also the wavelength of the infrared rays cannot be efficiently reflected, and a sufficient heat insulating effect cannot be obtained. The average particle diameter of the solar shading substance is preferably 0.4 μm or less, more preferably 0.3 μm or less. Further, the solar light shielding material is not limited as long as it can reflect the wavelength of infrared rays, and is preferably 0.05 μm or more, and more preferably 0.1 μm or more.

In addition, due to the near-infrared wavelength incident from the fiber surface Since the refractive index is different, the fiber passes through the center of the fiber. Therefore, instead of dispersing the solar shading substance such as titanium oxide in the fiber, it is highly filled in the core component, thereby effectively reflecting the near-infrared rays and obtaining a high degree of separation. Thermal effect. Further, when the concentration of the solar shading substance in the core component is higher than the concentration of the heat-insulating fine particles in the sheath component, not only the color rendering property but also the yarn making property can be maintained.

[sheath component (component B)]

Next, the heat insulating fine particle-containing polyester polymer (hereinafter sometimes simply referred to as a B component polymer) constituting the sheath component (component B) of the core-sheath type composite fiber of the present invention will be described.

The component B polymer, that is, the polyester polymer containing heat-insulating fine particles capable of maintaining color rendering properties, is a polyester such as polyethylene terephthalate or polybutylene terephthalate or the like. The ester is used as a main skeleton, and an aliphatic dibasic acid such as an isophthalic acid, a metal sulfonate-based phthalic acid, an aliphatic dibasic acid such as adipic acid or sebacic acid, or diethylene glycol is preferably used. A copolymerized polyester obtained by denaturation of a third component such as a polyhydric alcohol such as butanediol, hexanediol, cyclohexanedimethanol, bisphenol A, polyalkylene glycol or pentaerythritol.

Further, in the present invention, the heat-insulating fine particles contained in the component B are preferably inorganic fine particles capable of maintaining color rendering properties, and particularly preferably a monomer such as ceria or barium sulfate and a mixture thereof.

The average particle diameter of the heat-insulating fine particles is 0.1 μm or less, preferably 0.08 μm or less and 0.03 μm or more.

Further, the present invention can maintain not only the conventional dyeability of the polyester by containing 0.5% by weight or more and 10% by weight or less (preferably less than 10% by weight) of heat-insulating fine particles such as cerium oxide contained in the component B. ,and Can play a thermal insulation effect. When the heat insulating fine particles are less than 0.5% by weight, not only the yarn-making property is lowered, but also the heat insulating effect due to the heat-insulating fine particles cannot be obtained. On the other hand, if the content of the heat insulating fine particles exceeds 10% by weight, the spinnability at the time of spinning is extremely deteriorated. Or even if it is possible to spun, there is a problem that yarn breakage occurs in the stretching step, and in addition, it is sometimes impossible to obtain a quality that is satisfactory after the extension. It is preferably 0.5% by weight or more and 8% by weight or less, more preferably 1% by weight or more and 7% by weight or less.

[core sheath type composite fiber]

The core-sheath type composite fiber of the present invention can be produced by a production method described later, and the core water-sheath type composite fiber of the present invention preferably has a specific moisture content of 0.4% or more. When the specific moisture content of the conjugate fiber is less than 0.3%, a sufficient heat insulating effect may not be obtained due to a small latent heat of vaporization accompanying evaporation of water content.

According to the present invention, as shown in Fig. 1, when the distance from the center of gravity G of the cross-section of the fiber to the distance from the outer periphery of the fiber to the far point is R, the straight line distance from the center of gravity G to the far point of the core component is obtained. When r is set, R/r≧2 is preferable, and R/r≧3 is more preferable. When R/r < 1.8, the color development property of the composite fiber may be deteriorated due to the influence of a solar shielding substance (for example, titanium oxide) contained in the core component.

Further, in the core-sheath type composite fiber of the present invention, the mass ratio of the component A to the component B is 10:90 to 30:70, preferably 10:90 to 25:75, more preferably 10:90 to 20:80. . When the mass ratio of the component A polymer is less than 10%, the heat insulating effect of the core component becomes low. Further, when the mass ratio of the component A polymer is 30% or more, the color developability of the conjugate fiber is deteriorated.

In the above-mentioned conjugate fiber, the thickness of the fiber is not particularly limited, and it may be any thickness. However, in order to obtain a fiber having good color rendering properties, it is preferred that the conjugate fiber has a single fiber fineness of about 0.3 to 11 dtex in advance. . Further, not only long fibers but also short fibers can be expected from the effects of the present invention.

The core-sheath type composite fiber of the present invention has a high infrared reflectance. For example, the average reflectance of infrared rays having a wavelength of 800 to 1200 nm may be 70% or more, preferably 70.5% or more, and more preferably 71% or more.

The core-sheath type composite fiber of the present invention can suppress color abnormality of color due to whitening, and for example, the L* value can be 16.5 or less, preferably 16 or less.

The washing fastness of the conjugate fiber obtained in the present invention, which is fading, additional contamination, and liquid contamination, is preferably 4 or more. When any of them is 3 or less, it is not suitable for general clothing use based on the viewpoint of operability.

Further, the composite fiber obtained in the present invention preferably has a light fastness of 4 or more. When the light fastness is below 3, it is not suitable for general clothing use based on the viewpoint of operability.

The core-sheath type composite fiber of the present invention has practically sufficient strength in breaking strength, and the breaking strength obtained by the load-extension curve obtained by using an Instron type tensile testing machine is For example, it is about 1.5 to 10 cN/dtex, preferably about 1.8 to 8 cN/dtex, and more preferably about 2 to 6 cN/dtex.

The core-sheath type composite fiber of the present invention has practically sufficient elongation in elongation at break, and the tensile tester using the Instern type is used. The fracture elongation obtained by the load-extension curve obtained is, for example, about 10 to 80%, preferably about 20 to 70%, more preferably about 30 to 60%.

The method for producing the conjugate fiber of the present invention will be described next.

First, each of the component A polymer and the component B polymer are melt-extruded by a separate extruder, and introduced into respective spinning heads, and melt-spun by passing through a spinning metal nozzle of each composite shape for the purpose of formation. And can be manufactured. Moreover, in order to ensure the quality required for the final product and the good step passability, the most suitable spinning and stretching method can be selected. More specifically, it is a two-stage method in which the spinning-extension spinning method is performed in one stage, or the spinning raw yarn is taken in a separate step, and the non-stretched yarn is directly extracted without stretching. In the method of winding at a speed of 2000 m/min or more, the composite fiber product having good heat insulating effect and color rendering property can be obtained by performing product processing by an arbitrary wire processing step.

In the spinning step of the production method of the present invention, a normal melt spinning device is used and spun from a metal nozzle. Further, the cross-sectional shape and diameter of the obtained fiber can be arbitrarily set depending on the shape and size of the metal nozzle.

The conjugate fiber obtained in the present invention can be used as various fiber aggregates (fiber structures). Here, the fiber assembly is, of course, a woven fabric or a nonwoven fabric comprising the fibers of the present invention alone, or a woven or non-woven fabric using a part of the fibers of the present invention, such as natural fibers, chemical fibers, synthetic fibers, and the like. Woven fabric woven fabric or woven fabric used as blended yarn, mixed yarn, mixed non-woven fabric, etc. The proportion of the fibers of the present invention in the nonwoven fabric or nonwoven fabric is 10% by weight or more, preferably 30% by weight or more.

The main use of the fiber of the present invention is that, for the long fiber, a woven fabric or the like can be produced singly or in part, and a raw material for a clothing exhibiting a good touch can be obtained. On the other hand, in the case of short fibers, rayon, dry non-woven fabric, and wet non-woven fabric for clothing are used not only for clothing but also for non-clothing applications such as various living materials and industrial materials.

Hereinafter, the present invention will be described in detail by way of examples, but the invention should not be construed as limited. In addition, the measured value in the Example was measured by the following method.

<Insulation evaluation>

(△T measurement)

After the ΔT system was adjusted to have a uniform fiber diameter, the obtained conjugate fiber was used to refine a tubular knitted fabric having a basis weight of 200 g/m ² , and then irradiated with a reflector lamp, and the temperature immediately below the sample after 15 minutes was measured. The temperature was measured using an adhesive sensor TNA-8A of Tascojapan Co., Ltd., and evaluated for a temperature difference (ΔT ° C) for a polyethylene terephthalate fiber containing TiO ₂ of 0.05% by weight of a control sample. To indicate the degree of high temperature.

(reflection and penetration rate)

The reflection and the transmittance were measured by adjusting the fiber diameter to be uniform, and using the obtained composite fiber to refine a tubular knitted fabric having a basis weight of 200 g/m ² , and then measuring it using the measuring apparatus shown below.

Spectrophotometer: Spectrophotometer HITACHI C-2000S Color Analyzer

<staining method>

Dyes: DiacrylBlack BSL-F 7%omf

Dispersing aid: Disper TL (made by Mingcheng Chemical Industry Co., Ltd.) 1g/l

PH adjuster: ULTRA MT grade 1g/l

Bath ratio: 1:50 temperature: 130 ° C × 40 minutes

Restore

Sulfur hydride 1g/l

AMILADIN (First Industrial Pharmaceutical) 1g/l

NaOH 1g/l

Bath ratio: 1:30 temperature: 80 ° C × 120 minutes

<Color rendering>

(L* value)

For the obtained dye, a value measured by a Hitachi 307 color analyzer (Hitachi, Ltd.: automatic recording spectrophotometer) was used.

<Washing fastness>

The measurement was carried out in accordance with the measurement method of JIS L-0844.

<Light fastness>

The measurement was carried out in accordance with the measurement method of JIS L-0842.

<denier>

The measurement was carried out in accordance with the measurement method of JIS L-1013.

<breaking strength>

Load-extension curve obtained by using an Instron type tensile tester Line to find.

<breaking elongation>

Load-extension curve obtained by using an Instron type tensile tester Line to find.

<spinning property>

Spinning evaluation was performed in accordance with the following criteria.

◎: After continuous spinning for 24 hours, no yarn breakage occurred during spinning, and the obtained composite fiber did not produce fluff, loop, etc. at all, and the spinning property was extremely good.

○: After continuous spinning for 24 hours, the frequency of the broken yarn at the time of spinning was one or less, and no velvet was produced on the composite fiber. ‧The loop is a little bit, but the spinning is generally good.

△: Continuous spinning after 24 hours, broken yarn during spinning Up to 3 times, poor spinning

×: After continuous spinning for 24 hours, the yarn breakage occurred more than 3 times during spinning, and the spinning property was extremely poor.

(Example 1)

Core component: polydecylamine (component A polymer) containing 70% by weight of titanium oxide having an average particle diameter of 0.4 μm and sheath component: polyethylene terephthalate containing 1.0% by weight of cerium oxide (component B) The compound ratio (mass ratio) of the polymer) is 10:90, and the number of holes is 24 (aperture 0.25 mm) The metal nozzle is spun at a spinning temperature of 260 ° C and a single hole discharge amount = 1.42 g / min, and a cooling air having a temperature of 25 ° C and a humidity of 60% is blown to a spun yarn at a speed of 0.4 m / sec. After the yarn was made 60 ° C or lower, the length was set to 1.0 m at a position 1.2 m below the spinning metal nozzle, the inlet guide wire was 8 mm, the outlet guide wire was 10 mm, and the inner diameter was 30 mm. The tubular heater (internal temperature 185 ° C) is extended in the tubular heater, and the wire fed from the tubular heater is supplied with oil by a fuel nozzle, and is taken up by a detaching roller at a speed of 4000 m/min. The composite fiber filament of 84T/24f (strength 2.53 cN/dtex, elongation 40.2%). After the obtained composite fiber was used to refine a tubular knitted fabric having a basis weight of 200 g/m ² , various measurements were carried out. The linear distance from the center of gravity G of the cross-section of the composite fiber to the far point of the outer peripheral portion of the fiber is R, and when the linear distance from the center of gravity G to the far point of the core component is r, R/r= 3.2. The L* value, the reflectance, the ΔT (°C), and the spinning property at this time are shown in Table 1. The composite fiber obtained by the production method of the present invention has an L* value of 15.56, showing the same degree of color development as the conventional polyester fiber. Further, a high heat insulating effect of ΔT = -3.6 ° C was exhibited. In addition, the washing fastness and light fastness are both grade 4 or higher.

(Examples 2 to 11)

Next, the polymer of the components A and B, the added particles and the content of the component A and the component B were changed, and spinning was carried out in the same manner as in Example 1 to obtain 84T/24f of the composite fiber filament. The physical properties of the obtained fiber are shown in Table 1. Both are good L* values and ΔT, which are quality without any problem. Further, in Example 10, by using barium sulfate in the microparticles contained in the sheath component, a high heat insulating effect can be obtained while maintaining color rendering properties. In addition, the washing fastness and light fastness of any of the fibers are also above grade 4.

(Examples 12 to 13)

The core-sheath ratio of the conjugate fiber was changed, and spinning was carried out in the same manner as in Example 1 to obtain 84T/24f of the conjugate fiber filament. Both show excellent heat insulation and color rendering, and are of no problem quality. In addition, the washing fastness and light fastness of any of the fibers are also above grade 4.

(Comparative examples 1 to 8)

The addition particles and content of the polymer of the A component and the B component, the A component and the B component were changed, and the same was carried out in the same manner as in Example 1 to obtain 84T/24f of the composite fiber filament. The physical properties of the obtained fiber are shown in Table 1.

In Comparative Example 1, since the titanium oxide contained in the core component was 0%, the heat insulating effect could not be obtained. Further, in Comparative Example 2, since the content of titanium oxide was as large as 80% by weight, the spinnability at the time of spinning was extremely deteriorated, and spinning could not be performed.

In Comparative Example 3, since the cerium oxide contained in the sheath component was 0%, the heat insulating effect was insufficient, and unlike Examples 1 to 13, the fibers could not be obtained in one stage of spinning-extension. Further, in Comparative Example 4, since the content of cerium oxide was as much as 15% by weight, the spinning property at the time of spinning was extremely deteriorated, and spinning could not be performed.

In Comparative Example 5, the mass ratio of the core sheath component was 50:50, which showed a good heat insulating effect, but the content of the core component was large, resulting in lack of color development.

In Comparative Example 6, since titanium oxide was contained in the sheath component, it exhibited a good heat insulating effect, but the color rendering property was poor.

In Comparative Example 7, since the cerium oxide contained in the core component is not the solar opaque substance of the present invention, the heat insulating effect is poor.

In Comparative Example 8, since the particle diameter of the titanium oxide contained in the core component was 0.5 μm or more, the heat insulating effect could not be obtained.

[Industrial availability]

The conjugate fiber obtained by the present invention has high reflectance at a wavelength (for example, 800 to 3000 nm, especially 800 to 1200 nm) of infrared rays which are easily converted into thermal energy, and has the same color developability as a conventional polyester, so Suitable for all clothing.

As described above, the preferred embodiments of the present invention have been described with reference to the drawings, and as long as they have ordinary knowledge in the technical field to which the invention pertains, various modifications and corrections can be easily made within the scope of the invention with reference to the present specification. . Therefore, such changes and modifications are to be construed as being within the scope of the invention as defined by the scope of the claims.

Claims (7)

A core-sheath type composite fiber in which a core component is a thermoplastic polymer containing 8% by weight or more and 70% by weight or less of a solar light shielding material having an average particle diameter of 0.5 μm or less, and the sheath component is contained in an amount of 0.5% by weight or more and 10% by weight or less. A polyester-based polymer having an average particle diameter of 0.1 μm or less and an average particle diameter smaller than the above-mentioned solar shading substance, and capable of maintaining color rendering of the heat-insulating fine particles, and having a mass ratio of the core component to the sheath component of 10:90 to 30: 70. The solar shielding material is at least one selected from the group consisting of titanium oxide, zinc oxide, and barium sulfate, and the heat insulating fine particles are selected from at least one of cerium oxide and barium sulfate. The core-sheath type composite fiber according to claim 1, wherein the core component contains more than 20% by weight and less than 70% by weight of the solar shading substance. The core-sheath type composite fiber according to claim 1 or 2, wherein the fiber has a predetermined moisture content of 0.4% or more. The core-sheath type composite fiber according to claim 1 or 2, wherein the solar shading substance has an average particle diameter of more than 0.1 μm. The core-sheath type composite fiber according to claim 1 or 2, wherein a linear distance from a center point G of the cross section of the fiber to a far point of the outer circumference of the fiber is set to R, and a point G from the center of gravity to the core component When the straight line distance to the far point is set to r, R/r ≧ 1.8. The core-sheath type composite fiber according to claim 1 or 2, wherein an average reflectance of infrared rays having a wavelength of 800 to 1200 nm is 70% or more. The core-sheath type composite fiber according to claim 1 or 2, wherein the L* value is 16.5 or less.