JP7038481B2 - Heat storage and heat retention fiber - Google Patents

Description

The present invention relates to a sea-island type composite fiber having excellent heat storage and heat retention using a polypropylene resin containing an infrared absorber and a thermoplastic resin.

Many fibers that are required to retain heat, such as those used for winter clothing, have been proposed, such as moisture-absorbing heat-generating fibers, fibers that convert sunlight into heat, and hollow fibers.
Moisture-absorbing heat-generating fibers increase heat retention by generating heat when they absorb moisture, but they dissipate heat immediately and have low sustainability.
On the other hand, fibers that convert sunlight into heat always generate heat when irradiated with sunlight, so they are excellent in heat retention and durability. In Patent Document 1, a polyester containing titanium oxide surface-coated with tin oxide is arranged in the core portion, and a specific polyethylene terephthalate is arranged in the sheath portion to form a core-sheath fiber having good dyeability. Has been proposed. Further, Patent Document 2 proposes that a functional fiber having whiteness as well as excellent heat retention can be obtained by containing stannic oxide doped with antimony oxide and far-infrared radioactive fine particles.
In addition, since winter clothing uses more fibers than ordinary clothing and becomes heavy, it is also important to reduce the weight of the fibers. Examples of the lightweight fiber include fibers using polyolefin, but polyolefin is not dyeable and it is difficult to develop it for clothing applications. Therefore, Patent Document 3 proposes a spun yarn made of polyester fiber having a fiber cross-sectional hollow ratio of 50% or more. In this proposal, the hollow portion imparts lightness and heat retention to the spun yarn.

Japanese Patent Application Laid-Open No. 2003-0273337 Japanese Unexamined Patent Publication No. 2015-014076 Japanese Unexamined Patent Publication No. 2007-070768

However, when inorganic fine particles such as stannic oxide doped with antimony oxide are blended as in Patent Documents 1 and 2 in order to obtain sufficient heat retention, the specific gravity of the fiber becomes large and the winter clothing and the like feel heavy. It tends to be a certain clothing.
Further, the hollow fiber of polyethylene terephthalate as described in Examples of Patent Document 3 has a high specific gravity of polyethylene terephthalate of 1.38, and the hollow ratio is increased in order to improve the lightness, but the hollow ratio is high. In addition, since the hollow portion is cracked or crushed in the process of false twisting or twisting, there is a limit to imparting lightness.
Therefore, it is an object of the present invention to obtain a dyeable heat storage heat retention fiber having sufficient heat retention as a winter clothing and being lightweight.

In the present invention, the island component is made of a lightweight polypropylene resin containing an infrared absorber, the sea component is made of a dyeable thermoplastic resin, and the sea part and the island part have a specific fiber cross-sectional shape. It is a heat storage heat retaining fiber having.
That is, the gist of the present invention is that the joint surface between the sea part and 10 or more and 20 or less island parts has a continuous sea-island structure in the fiber length direction, and heat storage and heat retention satisfying the following (a) to ( d ). It is a sex fiber.
( A) Polypropylene resin containing 2% by mass or more and 15% by mass or less of an infrared absorber in the island component ( b ) Thermoplastic resin in which the sea component can be dyed ( c ) The area ratio of the sea part in the cross section of the fiber is 30% or more. , 70% or less ( d ) Even if the minimum thickness of the sea portion in the fiber cross section is 1 μm or more, the dyeable thermoplastic resin is preferably a polyester resin or a polyamide resin. Further, it is preferable that the fibers are not fused or fused after the dry heat treatment in a dry heat atmosphere of 170 ° C. Further, it is preferable that the single yarn fineness of the fiber is 1 dtex or more and the density is 1.25 g / cm ³ or less.
The present invention is also a fiber structure made of the above fibers.

The heat storage heat retention fiber of the present invention can improve the weight feeling of the fiber and can provide a fiber having a sufficient function as a winter clothing and having excellent heat storage heat retention and dyeability. Further, the heat storage heat retaining fiber of the present invention can be used in combination with a thermoplastic resin fiber such as a polyester fiber or a polyamide fiber.

FIG. 1 shows an example of the cross-sectional shape of the heat storage heat insulating fiber of the present invention. FIG. 2 shows an example of a cross-sectional shape of a heat storage heat insulating fiber outside the scope of the present invention.

The heat storage and heat retaining fiber of the present invention is composed of a sea portion composed of a sea component and an island portion composed of an island component.

The heat storage and heat retaining fiber of the present invention is composed of a thermoplastic resin in which the sea component can be dyed and a polypropylene resin in the island component, and the island component contains an infrared absorber.

Examples of the infrared absorber include antimony-doped tin oxide (ATO) and tin-doped indium oxide (ITO). In the case of ATO , it is preferable to contain 2% by mass or more and 15% by mass or less with respect to the polypropylene resin. If the content is less than 2% by mass, sufficient heat storage and heat retention cannot be obtained, and if it exceeds 15% by mass, the spinnability at the time of spinning is extremely deteriorated. Alternatively, even if spinning is possible, yarn breakage occurs in the drawing process, and the quality after drawing tends to be unsatisfactory. More preferably, it is 3% by mass or more and 12% by mass or less. In the case of ITO , it is preferable that it is contained in the polypropylene resin in the same proportion as ATO .

The particle size of the infrared absorber is preferably, for example, an average particle size of 10 μm or less. If the average particle size exceeds 10 μm, the spinning filter is likely to be clogged, yarn breakage, or the like is likely to occur . It is more preferably 10 nm or more and 5 μm or less, and further preferably 10 nm or more and 3 μm or less.

In the heat storage and heat retention fiber of the present invention, the polypropylene resin of the island component means a resin containing polypropylene (PP) as a main component. It may be a propylene homopolymer or a copolymer containing another component as a repeating unit. Examples of the copolymer include those obtained by copolymerizing one or more of ethylene, butene-1, hexene-1, and the like with propylene.

In the present invention, the melting point of the resin refers to the value indicated by the peak top of the endothermic peak when the temperature is raised to 300 ° C. at 10 ° C./min under a nitrogen atmosphere using a differential scanning calorimeter (DSC). ..

The melting point of the polypropylene resin is preferably 145 ° C. or higher and 200 ° C. or lower. If the melting point is lower than 145 ° C., sufficient heat resistance tends not to be obtained. If the melting point is higher than 200 ° C., it tends to be difficult to combine the sea component with the thermoplastic resin in melt spinning. Further, within the above range, when a fiber made of a thermoplastic resin such as a polyester resin or a polyamide resin is mixed to form a fiber structure, a dry heat treatment (dry heat treatment) in post-processing such as a preset or a final set, which is usually performed, is performed. For example, it is easy to obtain a material having sufficiently good heat resistance for performing a dry heat treatment at 120 to 190 ° C. or a dyeing treatment (for example, a wet heat treatment at 100 to 135 ° C.). More preferably, the melting point of the polypropylene resin is 160 ° C. or higher and 200 ° C. or lower.

The melt frate (MFR) of the polypropylene resin at 230 ° C. and a load of 2.16 kg is preferably 9 g / 10 min or more and 30 g / 10 min or less. That is, when the MFR is 9 g / 10 min or more, there is a tendency that agglomerates are unlikely to occur due to fusion between the islands, so that detachment between the sea and the islands is unlikely to occur. As a result, the spinning stability in the spinning process and the twisting process is good, and there is a tendency that dyeing spots such as a whitening phenomenon are less likely to occur after dyeing. Further, from the viewpoint of maintaining good mechanical strength of the fiber, the MFR is preferably 30 g / 10 min or less. Therefore, when the MFR is within the above range, fusion between the islands is unlikely to occur, there is no separation between the sea and the islands, and it is easy to obtain fibers having good mechanical strength. Above all, the MFR is preferably 9 g / 10 min or more, and preferably 20 g / 10 min or less. More preferably, it is 9 g / 10 min or more and 15 g / 10 min or less.

In the heat storage and heat retaining fiber of the present invention, the sea component is not particularly limited as long as it is a dyeable thermoplastic resin. Specific examples include polyester resin, polyamide resin, and polyvinyl alcohol resin. Among these, polyester resin and polyamide resin are preferable from the viewpoint of heat resistance and mechanical properties.

The sea component thermoplastic resin preferably has a melting point of 180 ° C. or higher and 280 ° C. or lower.
In the present invention, the island portion is covered with the sea component of the sea portion, and has good heat resistance that does not cause any problem even in dry heat treatment in post-processing such as a normal preset or final set. If the melting point of the sea component is too low, the dry heat treatment tends to cause melting of the sea part and harden the texture. If it is too high, compound spinning with sea components tends to be difficult. Therefore, the above range is preferable from the viewpoint of heat resistance, stable silk reeling property, and easy suppression of peeling between the sea part and the island part. The melting point of the thermoplastic resin having a more preferable sea component is 210 ° C. or higher and 270 ° C. or lower, and more preferably 220 ° C. or higher and 265 ° C. or lower.

The sea component polyester resin may be a linear saturated polyester produced by a polycondensation reaction using dicarboxylic acids or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof as raw materials, and may be polyethylene terephthalate, polytrimethylene terephthalate, or poly. Examples thereof include butylene terephthalate, polyethylene naphthalate, polylactic acid and the like, but the present invention is not limited thereto. In particular, those mainly composed of polyethylene terephthalate are preferable, and homopolyester or copolyester may be used. Examples of the copolymerization component include adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyldicarboxylic acid, 5-sodiumsulfoisophthalic acid, diphenylsulfonicdicarboxylic acid, p-oxyethoxybenzoic acid and the like. Examples thereof include those containing a dicarboxylic acid or an ester-forming derivative component thereof, or a polyalkylene glycol component such as polyethylene glycol, polytetramethylene glycol, or polyhexanemethylene glycol. These copolymerization components may be used one by one, or two or more of them may be used.

Examples of the polyamide resin having a sea component include, but are not limited to, a single polymer such as polyamide 6, polyamide 10, polyamide 12, and polyamide 66, or a copolymer.

The sea component and the island component may be modified by adding an additive within a range that does not impair the effect of the present invention. Examples of the additive include a compatibilizer, a heat stabilizer, an antioxidant, a fluorescent whitening agent and the like. In addition, the additive may be used alone or in combination.

The cross-sectional shape of the heat storage heat insulating fiber of the present invention will be described below.

The heat storage heat insulating fiber of the present invention is a composite fiber having a sea-island structure in which one or more sea parts and two or more island parts are continuously formed in the length direction. Further, it is preferable that the joint surface between the sea portion and the island portion has a sea-island structure which is continuous without interruption in the fiber length direction.

In the heat storage and heat retaining fiber of the present invention, the sea component is exposed on the fiber surface. That is, in the fiber cross section (fiber cross section perpendicular to the fiber length direction), the sea portion is exposed on the outer circumference.

FIG. 1 is a diagram showing an example of the cross-sectional shape of the fiber cross section of the heat storage heat insulating fiber of the present invention. In this example, 19 islands b having a round cross section are arranged in a sea portion a of a fiber having a round cross section so as to be close to the center of the fiber. The 19 islands b have one round cross section in the center of the fiber, six round cross sections arranged on the first circumference at approximately equal intervals around the center of the fiber, and the outer circumference on the first circumference. It is composed of 12 round cross sections arranged at approximately equal intervals. In this way, one island part is arranged in the center of the fiber, and the island part is arranged on a double circle around the island part. The minimum thickness of the sea part is 1 μm or more. Here, the minimum thickness of the sea portion is the shortest distance between the outer circumference of the fiber and the outer circumference of the island, and when the normal line of the outer circumference of the fiber (a straight line passing through one point on the outer circumference of the fiber and perpendicular to the tangent line at this point) is drawn. Shows the distance to the outer circumference of the nearest island. For example, in the heat storage and heat retaining fiber of FIG. 1, a normal line is drawn from the point p on the outer circumference of the fiber, and the intersection with the outer circumference of the island portion b is defined as q. In the cross section of the fiber, the shortest length X of the line segment pq connecting the points p and q is the minimum thickness of the sea portion.
When the minimum thickness of the sea portion is less than 1 μm, it becomes difficult to suppress the exposure of the infrared absorber on the island portion to the fiber surface. When the infrared absorber is exposed on the fiber surface, the guides and rollers are likely to be severely worn in the spinning process, the drawing process, and the weaving and knitting process. Further, in the stretching step, the weaving and knitting step, and the dyeing step, peeling between the sea component and the island component is likely to occur. For this reason, dyeing spots such as deterioration of silk reeling stability, weaving and knitting stability, and whitening phenomenon are likely to occur. In addition, the islands are melted by the dry heat treatment, and the texture tends to be hard.
A more preferable minimum thickness of the sea portion is 1.2 μm or more. The upper limit of the minimum thickness of the sea part will be described later, but it is preferably 4.0 μm or less from the viewpoint of not increasing the density of the island part.

In the fiber cross section of the heat storage heat retaining fiber of the present invention, the number of islands is preferably 40 or less. When the number of islands is 40 or less, it becomes easy to stably obtain heat storage and heat insulating fibers having appropriate strength and which are unlikely to be separated from the sea and islands. On the other hand, when the number of islands exceeds 40, the density of the islands in the fiber becomes large, and the islands are fused with each other in the spinning process to easily generate agglomerates, resulting in separation of the sea and the islands. It tends to be easier. Further, from the viewpoint of ensuring the formation of a more stable fiber cross section, the number of islands to be arranged is more preferably 20 or less. By setting the number of islands to such a number, it becomes easier to suppress aggregation between the islands. In addition, the number of islands to be arranged is preferably 3 or more, more preferably 10 or more, from the viewpoint of preventing peeling while increasing the joint area between the sea and the islands.

In the fiber cross section of the heat storage heat retaining fiber of the present invention, the islands are approximately evenly spaced on the circumference of the concentric circle with the center of the fiber so that stress can be easily dispersed from the viewpoint of suppressing the separation between the sea and the island. It is preferable to be arranged in. Here, the circle on which the island portion is arranged may be a single circle or a double circle or more, but is preferably a double circle or more. When it is a double circle or more, it becomes easier to disperse the shrinkage stress when the heat treatment is performed in the subsequent step, and the separation between the sea part and the island part can be suppressed more efficiently.

In the fiber cross section of the heat storage heat retaining fiber of the present invention, the area ratio of the sea portion to the entire fiber cross section is composed of 30% or more. That is, when the area ratio of the sea part is less than 30% in the fiber cross section, the distance between the island parts is narrowed, the islands are fused with each other, and the sea part and the island part are likely to be separated. Become. Further, since the color tends to be light after dyeing, the area ratio is preferably 35% or more, more preferably 40% or more.

In the fiber cross section of the heat storage heat retaining fiber of the present invention, the area ratio of the island portion to the entire fiber cross section is preferably 70% or less. The area ratio of the islands may be appropriately set in consideration of the balance between lightness and dyeability.

In the fiber cross section of the heat storage heat retaining fiber of the present invention, it is preferable that the island portion is arranged in the central portion within a range in which the island portions do not fuse with each other. For example, when the fiber radius is r in the fiber cross section, it is preferable to arrange the island portion in a range of [radius r × 0.90] or less from the fiber center point, and more preferably [radius r × 0.85]. ] The islands should be placed in the following areas. As a result, the minimum thickness of the sea portion is likely to be 1 μm or more, and there is a tendency that the stability of silk reeling, deterioration of weaving and knitting stability, and dyeing spots such as whitening phenomenon are easily suppressed.

In the heat storage and heat retaining fiber of the present invention, the total fineness is preferably 40 dtex or more and 200 dtex or less from the viewpoint of silk reeling stability. It is more preferably 40 dtex or more and 150 dtex or less, and further preferably 40 dtex or more and 100 dtex or less.

Further, in the heat storage and heat retaining fiber of the present invention, it is preferable that the single yarn fineness is 1 dtex or more. If the single yarn fineness is less than 1 dtex, it tends to be difficult to maintain the minimum thickness of the sea portion to 1 μm or more, and dyeing spots such as deterioration of silk reeling stability and weaving and knitting stability, and whitening phenomenon are likely to occur. Further, from the viewpoint of the texture when made into a woven fabric, the single yarn fineness is preferably 5 dtex or less. If it exceeds 5 dtex, the texture tends to be hard when it is made into a woven fabric. It is more preferably 4 dtex or less, still more preferably 3 dtex or less.

In the heat storage heat insulating fiber of the present invention, the strength is preferably 2.0 cN / dtex or more and 5.5 cN / dtex or less from the viewpoint of post-processing. More preferably, it is 2.5 cN / dtex or more and 5.0 cN / dtex or less.

In the heat storage and heat retaining fiber of the present invention, the elongation is preferably 20% or more and 45% or less from the viewpoint of post-processing. More preferably, it is 25% or more and 40% or less.

The density of the heat storage heat retaining fiber of the present invention will be described. Polypropylene, which is an island component, has a density of about 0.91 g / cm ³ and is excellent in lightness. On the other hand, in the present invention, the sea component is made of a dyeable thermoplastic resin. Therefore, the density of the heat storage heat insulating fiber of the present invention changes according to the area ratio of the island portion in the cross section of the fiber. From the viewpoint of lightness, it is better that the area ratio of the island component made of polypropylene resin having a low density is large, but from the viewpoint of dyeability, it is preferable that the area ratio of the island component made of a thermoplastic resin having a higher density than polypropylene is large. Considering these balances, the lower limit of the area ratio of the sea portion in the fiber cross section is 30%, preferably 35%, and more preferably 40%. The upper limit of the area ratio of the sea part is 70%, preferably 65%, and more preferably 60%. Within such a range, it becomes easy to obtain a heat storage heat retaining fiber having excellent both light weight and dyeability.

In the present invention, heat resistance will be described. It is preferable that the heat storage heat retaining fiber of the present invention is one in which melting and fusion do not occur by dry heat treatment at 170 ° C. Normally, weaving and knitting fabrics need to be subjected to dry heat treatment such as presets and final sets. In the case of a fabric using polyester fiber or polyamide fiber, heat treatment is usually performed at 120 ° C to 190 ° C. If fibers with low heat resistance are used together at that time, the fibers will be fused or fusing during the dry heat treatment, resulting in a fabric with a hard texture or a fabric with holes, which should be used for clothing and industrial materials. Cannot be done. From this point of view, the higher the heat resistance, the better, and it is preferable that fusion and fusing do not occur in the dry heat treatment at 170 ° C.

The heat storage heat insulating fiber of the present invention can be used in the form of staples, spun yarns, filaments and the like. In addition, peeling between the sea part and the island part is unlikely to occur, and the bleaching phenomenon can be suppressed. Further, since it has sufficient strength and elongation, it can be suitably used as a long fiber.

Various fiber structures can be obtained by using the heat storage heat insulating fiber of the present invention. The fiber structure takes the form of, for example, a bundle of yarns such as twisted yarns and braids, processed yarns such as false twisted yarns and Taslan processed yarns, spun yarns, various mixed yarns, fabrics such as woven and knitted fabrics and non-woven fabrics, and stuffed cotton. be able to.
In particular, if it is a fiber structure made of a fiber made of a thermoplastic resin such as a polyester fiber or a polyamide fiber and a fabric such as a mixed fiber, a mixed weave, a mixed knitted knitted fabric, or a non-woven fabric, the dyeability, heat resistance, lightness, etc. It is preferable in that the features can be appropriately utilized and used.

Next, a preferred example of the method for producing the heat storage heat insulating fiber of the present invention will be described.

First, the polypropylene resin of the island component and the thermoplastic resin of the sea component are prepared.
The prepared sea component and island component are separately melted, discharged from a spinneret so as to have the above cross-sectional shape, cooled, and then stretched to obtain the heat storage heat retaining fiber of the present invention.
Here, the method of adding the infrared absorber to the island component is not particularly limited, but from the viewpoint of uniform dispersion, the infrared absorber is kneaded in advance with the polypropylene resin of the island component using a twin-screw extruder to form a master chip. It is preferable to do so.

The spinning temperature is preferably 220 ° C. or higher and 300 ° C. or lower, more preferably 250 ° C. or higher and 290 ° C. or lower, from the viewpoint of heat resistance and spinnability of the polypropylene resin and the thermoplastic resin. The spinning speed is preferably 800 m / min or more and 4500 m / min or less, and more preferably 1000 m / min or more and 3800 m / min or less.

In the heat storage and heat retaining fiber of the present invention, it is preferable that the sea portion and the island portion are continuously bonded to each other in a continuous state in the length direction of the fiber. In this case, peeling between the sea part and the island part is unlikely to occur in the stretching step, the weaving and knitting step, the dyeing step, and the like, and it is easy to suppress the deterioration of the yarn-making stability and the whitening phenomenon. On the other hand, if the resin in the island portion is interrupted in the length direction of the fiber, it tends to be difficult to suppress dyeing spots such as deterioration of silk reeling stability and whitening phenomenon, which is not preferable.

The stretching temperature is preferably 90 ° C. or higher and 120 ° C. or lower, more preferably 95 ° C. or higher and 110 ° C. or lower, from the viewpoint of silk reeling stability. The draw ratio is preferably about 2.0 times or more and 3.5 times or less from the viewpoint of stably obtaining the cross-sectional shape of the heat storage heat retaining fiber.

When producing the heat storage heat insulating fiber of the present invention, an arbitrary method such as a method of melt-spinning and then winding and stretching once, or a direct spinning and stretching method of melt-spinning and then stretching without winding once is adopted. can do.

The heat storage heat-retaining fiber of the present invention thus obtained has no peeling between the sea part and the island part, has good yarn-making stability, and has good heat resistance. It is difficult to peel off in each process such as scouring process and dyeing process, and it is excellent in handleability in each process. In particular, since dyeing spots such as a whitening phenomenon do not occur during dyeing, it is possible to dye in a dark color.

Hereinafter, examples of the present invention will be specifically described, but the following examples are examples of the present invention and do not limit the present invention. The methods for measuring and evaluating various physical properties were as follows.

(1) Melting point Using a differential scanning calorimeter (DSC) (“DSC 8230” manufactured by Rigaku), the temperature is raised to 300 ° C at a heating rate of 10 ° C / min in a nitrogen atmosphere, and the peak top of the heat absorption peak is thermoplastic. The melting point of the resin was used.

(2) Silk reeling stability The silk reeling stability was evaluated by the average number of yarn breaks when 10 kg of yarn was produced, and B or higher was judged as acceptable according to the following criteria.
A: When the number of thread breaks is less than 1 B: When the number of thread breaks is 1 or more and less than 3 C: When the number of thread breaks is 3 or more

(3) Confirmation of island part condition (fusion / peeling) and minimum thickness of sea part Any two points of the obtained heat storage heat insulating fiber are cut vertically in the length direction, and the cut surface is cut at 1500 times with an electron microscope. By observing, the occurrence of fusion and detachment of the islands was confirmed. Those without these defects were regarded as "good". In addition, the minimum thickness of the sea part was measured on the same cut surface.

(4) Strength and Elongation of Fiber A tensile test was conducted using an autograph AGS manufactured by Shimadzu Corporation in accordance with JIS L1013, and the fiber broke under the conditions of measurement length: 200 mm and tensile speed: 200 mm / min. The breaking strength and the breaking elongation at that time were measured 5 times each, and the average value was obtained.

(5) Evaluation of Density and Lightness The density of the obtained heat storage heat insulating fiber was calculated by the density gradient tube method according to the JIS K7112 D method. An immersion liquid prepared by using an aqueous solution of zinc chloride as a heavy liquid and ethanol as a light liquid was prepared in a density gradient tube, and allowed to stand in a constant temperature bath at 23 ° C. for 24 hours. The sample was placed in a density gradient tube and allowed to stand for 1 hour, and then the floating and sinking states were confirmed. Lightness was evaluated based on the following criteria.
◯: Density is 1.25 g / cm ³ or less ×: Density exceeds 1.25 g / cm ³

(6) Heat resistance evaluation After opening the tubular knitted fabric made of the obtained heat storage and heat retention fiber, it was fixed in a frame of 20 cm × 25 cm and subjected to dry heat treatment with hot air at 170 ° C. for 1 minute. The state of the yarn was observed at 1000 times with an electron microscope on the fabric after the dry heat treatment. In addition, the texture was confirmed by touch and evaluated according to the following criteria.
◯: When there is no yarn fusion or fusing and the texture does not become hard ×: When there is yarn fusion or fusing and the texture becomes hard

(7) Evaluation of dyeability The tubular knitted fabric made of the obtained heat storage and heat retention fibers was scoured at 70 ° C. for 20 minutes, washed with water, air-dried, and disperse dye (Dianix (registered trademark) Blue ACE). 0% o. w. f, bath ratio 1:50, high pressure dyeing at 130 ° C. for 1 hour, reduction washing was performed by a conventional method, and evaluation was performed according to the following criteria.
◯: When there is no bleaching phenomenon △: When there is no bleaching phenomenon but there is stain spots ×: When there is bleaching phenomenon

(8) Evaluation of heat storage and heat retention properties A 5 mm space is provided on the back surface of the tubular knitted fabric made of the obtained heat storage and heat retention fibers and the tubular knitted fabric (reference fabric) of the reference fibers, and black paper is placed on the black paper. A thermocouple temperature sensor was attached to the central part, and a 500 W reflex lamp was irradiated for 10 minutes from 50 cm above the sample surface. The temperature difference from the standard fiber tube knitted fabric was measured and evaluated according to the following criteria.
◯: When the temperature difference is + 3 ° C or more 10 minutes after irradiation and the temperature difference is + 2 ° C or more 1 minute after the light is turned off. in the case of

[Example 1]
Polyethylene terephthalate (melting point) is made of polypropylene resin containing 4% by mass of antimony-doped tin oxide (ATO), which is an infrared absorber, to polypropylene resin ("SA01A" manufactured by Japan Polypropylene, MFR 9g / 10min, melting point 164 ° C.). 258 ° C) is used as the sea component and supplied so that the area ratio of the sea part: island part is 40:60, and 19 island components are spun at 288 ° C from the base placed in the center of the fiber as shown in Fig. 1. It was taken out, stretched at a draw ratio of 2.7 times, and wound at a rate of 3000 m / min to obtain a heat-storing heat-retaining fiber of 67 dtex / 24 f. The minimum thickness of the sea portion in the fiber cross section of the obtained heat storage and heat retaining fiber was 1.2 μm, no peeling was observed at the interface between the sea portion and the island portion, and the silk reeling stability was good. Even after a dry heat treatment at 170 ° C. for 1 minute, there was no fusion or fusing, and the heat resistance was excellent. The dyeability was excellent in lightness with no whitening phenomenon and a density of 1.115 g / cm ³ . Further, in the heat storage heat retention evaluation, the irradiation 10 was compared with the reference cloth obtained by using the composite fiber produced by the same method as in Example 1 except that the polypropylene resin to which ATO was not added was used as the island component. After 1 minute, the temperature was + 5.5 ° C, and after 1 minute, the temperature was + 5.2 ° C, indicating excellent heat storage and heat retention. The results obtained are shown in Table 1.

[Example 2]
The heat storage and heat retaining fibers were produced by the same method as in Example 1 except that the area ratio of the sea part: the island part was 60:40. The minimum thickness of the sea part in the fiber cross section of the obtained heat storage and heat retention fiber was 1.5 μm, no peeling was observed at the interface between the sea part and the island part, and the yarn-making stability, heat resistance, and dyeability were good. rice field. The density was 1.210 g / cm ³ , which was excellent in lightness. Further, in the evaluation of heat storage and heat retention, the heat storage and heat retention was excellent at + 3.5 ° C. 10 minutes after irradiation and + 3.6 ° C. 1 minute after extinguishing. The results obtained are shown in Table 1.

[ Reference Example 3]
A heat storage heat insulating fiber was produced by the same method as in Example 1 except that a base having seven island components was used. The obtained heat storage heat-retaining fiber had a total of seven round cross sections, one in the center of the fiber and six in the circumference of the concentric circles at the same interval. The minimum thickness of the sea portion in the cross section of the fiber was 1.2 μm, no peeling was observed at the interface between the sea portion and the island portion, and the spinning stability and heat resistance were good. The stainability did not cause whitening, but stain spots were formed. The density was 1.120 g / cm ³ , which was excellent in lightness. Further, in the evaluation of heat storage and heat retention, the heat storage and heat retention was excellent at + 5.3 ° C. 10 minutes after irradiation and + 4.8 ° C. 1 minute after extinguishing. The results obtained are shown in Table 1.

[Comparative Example 1]
A heat storage heat retaining fiber was produced by the same method as in Example 1 except that the polyethylene terephthalate resin in which 6.5% by mass of ATO was added to the polyethylene terephthalate resin was used as the island component. Although the silk reeling stability, heat resistance, and dyeability are good, the density is 1.417 g / cm ³ , which is a heavy fiber. Further, in the evaluation of heat storage and heat retention, the heat storage and heat retention was excellent at + 3.6 ° C. 10 minutes after irradiation and + 4.1 ° C. 1 minute after extinguishing. The results obtained are shown in Table 1.

[Comparative Example 2]
The heat storage and heat insulating fibers were produced by the same method as in Example 1 except that a mouthpiece in which 19 island components were arranged so that the minimum thickness X of the sea portion of the sea portion in FIG. 1 was 0 μm was used. Some of the islands of the obtained heat storage and heat insulating fibers were exposed to the surface. In addition, peeling was observed at the interface between the sea part and the island part, the silk reeling stability was poor, and a whitening phenomenon occurred after dyeing. Fusing and fusing occurred in the dry heat treatment at 170 ° C. for 1 minute, and the heat resistance was not good. The density was 1.121 g / cm ³ , which was excellent in lightness. In the evaluation of heat storage and heat retention, the heat storage and heat retention was excellent at + 3.2 ° C. 10 minutes after irradiation and + 3.4 ° C. 1 minute after extinguishing. The results obtained are shown in Table 1.

[Comparative Example 3]
The heat storage and heat retaining fibers were produced by the same method as in Example 1 except that the area ratio of the sea part: the island part was 25:75. The obtained heat storage and heat insulating fibers were fused with island components to form a core sheath having one core. After staining, a whitening phenomenon occurred. The density was 1.048 g / cm ³ , which was excellent in lightness. In the evaluation of heat storage and heat retention, the heat storage and heat retention was excellent at + 5.0 ° C. 10 minutes after irradiation and + 5.1 ° C. 1 minute after extinguishing. The results obtained are shown in Table 1.

The heat storage heat insulating fibers obtained in Examples 1 to 3 had good peel resistance, heat resistance, light weight, and heat storage heat retention and could be dyed, but the heat storage heat retention fibers obtained from Comparative Examples had good heat storage resistance. At least one of peelability, dyeability, heat resistance, light weight, and heat storage and heat retention was poor.

Since the heat storage heat-retaining fiber of the present invention has sufficient heat-retaining property as winter clothing, is lightweight and dyeable, it can be used as various fiber structures, and can be used for winter clothing and the like. It can be suitably used.

a Sea part b Island part p Contact point on the outer circumference of the fiber q Intersection point between the normal on the outer circumference of the fiber and the outer circumference of the island part X Minimum thickness of the sea part

Claims (6)

It consists of a sea part and 10 or more and 20 or less island parts, and the joint surface between the sea part and the island part has a continuous sea island structure in the fiber length direction, and heat storage satisfying the following (a) to ( e ). Heat retention fiber.
(A) Polypropylene resin containing 2% by mass or more and 15% by mass or less of an infrared absorber in the island component (b) Thermoplastic resin in which the sea component can be dyed (c) The area ratio of the sea part in the fiber cross section is 30% or more. 70% or less (d) The minimum thickness of the sea part in the fiber cross section is 1 μm or more.
(E) A polypropylene resin having a melt flow rate of 9 g / 10 min or more and 30 g / 10 min or less at 230 ° C. and a load of 2.16 kg is used as the island component. The heat storage and heat retaining fiber according to claim 1, wherein the dyeable thermoplastic resin is a polyester resin or a polyamide resin. The heat storage heat retaining fiber according to claim 1 or 2, which is not fused or fused after dry heat treatment in a dry heat atmosphere at 170 ° C. The heat storage heat insulating fiber according to any one of claims 1 to 3, wherein the density is 1.25 g / cm ³ or less. The heat storage heat insulating fiber according to any one of claims 1 to 4, wherein the single yarn fineness is 1 dtex or more. A fiber structure composed of the heat storage heat retaining fiber according to any one of claims 1 to 5.

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