FIBER FOR ARTIFICIAL HAIR AND HEAD ACCESSORY PRODUCT

Abstract

A fiber for artificial hair constituted of a resin composition containing an aliphatic polyamide. A weight average molecular weight Mw of a dissolved component obtained when the fiber for artificial hair is dissolved in hexafluoroisopropanol is 46,000 or more and less than 65,000.

Claims

1. A fiber for artificial hair composed of a resin composition containing an aliphatic polyamide, wherein a weight average molecular weight Mw of a dissolved component obtained when the fiber for artificial hair is dissolved in hexafluoroisopropanol is 46,000 or more and less than 65,000.

2. The fiber for artificial hair according to claim 1, wherein the resin composition contains an aliphatic polyamide (A) having a weight average molecular weight of 70,000 or more and 150,000 or less and an aliphatic polyamide (B) having a weight average molecular weight of 40,000 or more and 55,000 or less.

3. The fiber for artificial hair according to claim 2, wherein a content of the aliphatic polyamide (A) with respect to the entire resin composition is 20% by mass or more and 80% by mass or less, and a content of the aliphatic polyamide (B) with respect to the entire resin composition is 20% by mass or more and 80% by mass or less.

4. The fiber for artificial hair according to claim 1, wherein the resin composition further contains a semi-aromatic polyamide, and a content of the semi-aromatic polyamide with respect to the entire resin composition is 1% by mass or more and 20% by mass or less.

5. The fiber for artificial hair according to claim 1, wherein the aliphatic polyamide is at least one selected from the group consisting of polyamide 6 and polyamide 66.

6. A head accessory product using the fiber for artificial hair according to claim 1.

Description

EXAMPLE 1

[0049] Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited thereto.

[0050] The aliphatic polyamides and semi-aromatic polyamides dried so as to have a moisture absorption rate of less than 1,000 ppm were blended so as to have the blending ratios shown in Tables 1-1 and 1-2. Details of the used aliphatic polyamides and semi-aromatic polyamides are as follows, and these were obtained by a known production method described in JP-A-2008-274086 and the like.

[0051] Aliphatic polyamide A: nylon 66, weight average molecular weight Mw 90,000, manufactured by DuPont, Zytel 42A

[0052] Aliphatic polyamide B: nylon 66, weight average molecular weight Mw 50,000, Toray Industries, Inc., MILAN CM3001-N

[0053] Aliphatic polyamide C: nylon 66, weight average molecular weight Mw 160,000, manufactured in-house

[0054] Aliphatic polyamide D: nylon 66, weight average molecular weight Mw 60,000, manufactured in-house

[0055] Aliphatic polyamide E: nylon 66, weight average molecular weight Mw 30,000, manufactured in-house

[0056] Semi-aromatic polyamide: nylon 10T, TVESTAMID HO Plus M3000, manufactured by Daicel Evonik Ltd.

[0057] The blended material or the material used alone was kneaded using a φ30 mm twin-screw extruder to obtain raw material pellets for spinning.

[0058] Then, after dehumidifying and drying the pellets so that the water absorption rate was 1,000 ppm or less, spinning was performed using a φ40 mm single-shaft melt-spinning device, and while cooling a molten resin discharged from a die having a hole diameter of 0.5 mm/piece through a water tank at about 30° C., a discharge amount and a winding speed were adjusted to prepare an undrawn yarn having a set fineness. A set temperature of the φ40 mm melt-spinning device was appropriately adjusted according to the ratio of the addition amount of the aliphatic polyamides and the semi-aromatic polyamides.

[0059] The obtained undrawn yarn was drawn at 100° C., and then annealed at 180° C. to obtain a fiber for artificial hair having a predetermined fineness. Drawing was performed at a draw magnification of 3 times and a relaxation rate at a time of annealing of 5%. The relaxation rate at the time of annealing is a value calculated by (rotational speed of the take-up roller at the time of annealing)/(rotational speed of the feeding roller at the time of annealing).

[0060] Regarding the obtained fiber for artificial hair, evaluation was performed for weight average molecular weight, number average molecular weight, tactile sensation, and curl settability according to the evaluation methods and criteria to be described later. The evaluation results are shown in Tables 1-1 and 1-2.

[0061] [Weight Average Molecular Weight Mw, Number Average Molecular Weight Mn]

[0062] Using a solution obtained after mixing and stirring the obtained fiber for artificial hair and hexafluoroisopropanol at 25° C. for 6 hours using an ultrasonic cleaner, using gel permeation chromatography, the following measurements were performed.

[0063] The weight average molecular weight Mw and the number average molecular weight Mn were obtained by measurement under the following equipment and conditions. [0064] Used device: Pump . . shodex DS-4 [0065] Column . . shodex GPC HFIP-806M×2+HFIP-803 [0066] Detector . . shodex RI-71

[0067] Eluent: Hexafluoroisopropanol (+additive CF.sub.3COONa (5 mmol/L))

[0068] Pre-treatment: Filtration with membrane filter—(0.2 μm)

[0069] Concentration: 0.2 w/v%

[0070] Injection amount: 100 μL

[0071] Column temperature: 40° C.

[0072] Flow rate: 1.0 ml/min

[0073] Standard substance: Standard polymethylmethacrylate (PMMA)

[0074] A calibration curve was prepared by standard PMMA, and a weight average molecular weight Mw and a number average molecular weight Mn were expressed by PMMA conversion values.

[0075] [Tactile Sensation (Squeakiness)]

[0076] The tactile sensation (squeakiness) of the fiber for artificial hair of each example and each comparative example was evaluated by the following method.

[0077] Using a fiber bundle sample in which fibers for artificial hair were bundled to a length of 250 mm and a weight of 20 g, evaluation was performed by determination by touch of 10 treatment technicians of fiber for artificial hair (with 5 years or more of work experience) according to the following evaluation criteria.

[0078] A (excellent): Nine or more technicians evaluated that the squeakiness was low.

[0079] B (good): Seven or eight technicians evaluated that the squeakiness was low.

[0080] C (bad): Six or less technicians evaluated that the squeakiness was low.

[0081] The lower the squeakiness of the fiber for artificial hair, the better the tactile sensation becomes.

[0082] [Curl Settability]

[0083] The curl settability of the fiber for artificial hair of each example and each comparative example was evaluated by the following method.

[0084] The fiber for artificial hair was adjusted to a length of 50 cm and a total weight of 2. 0 g to forma fiber bundle, the fiber bundle was wound around an iron (iron diameter 1.4 cm) made of iron at 180° C. to be curled, then the fiber bundle was separated from the iron, and it was checked whether or not there was curl when an end was fixed and suspended. A curled state was defined as a case where an interval between a base end and a tip end of the fiber for artificial hair when suspended was less than 0.85 times (less than 42.5 cm) the total length of 50 cm before curling. As a sample before evaluation, a sample stored at a temperature of 23° C. and a humidity of 50% for 24 hours was adopted in order to eliminate variations in evaluation. The curl settability of the fiber for artificial hair was determined according to the following criteria depending on the heating time with the iron required for the curl setting.

[0085] A (excellent): The curl was set when the heating time with an iron was less than 5 seconds.

[0086] B (good): The curl was set when the heating time with an iron was 5 seconds or more and less than 10 seconds.

[0087] C (bad): The curl was set when the heating time with an iron was 10 seconds or more.

[0088] [Processability]

[0089] Regarding the processability of undrawn yarns made of fibers for artificial hair in each example and each comparative example, the number of yarn breakages that occurred when 100 bundles of undrawn yarns were subjected to drawing treatment at three times of the draw magnification for 30 minutes was evaluated. Specifically, after the drawing treatment for 30 minutes, the obtained drawn yarn was visually observed, the number of yarn breakages was counted, and the processability was evaluated according to the following evaluation criteria.

[0090] A (excellent): Yarn breakage was 0 times/30 minutes

[0091] B (good): Yarn breakage was 1 time or more and less than 3 times/30 minutes

[0092] C (bad): Yarn breakage was 3 times or more and less than 10 times/30 minutes

TABLE-US-00001 TABLE 1-1 Unit Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Blending Aliphatic polyamide A Mass % 30 50 70 45 — — — — ratio of (weight average resin molecular weight Mw: composition 90,000) Aliphatic polyamide B Mass % 70 50 30 50 — 50 — 50 (weight average molecular weight Mw: 50,000) Aliphatic polyamide C Mass % — — — — 50 50 50 — (weight average molecular weight Mw: 160,000) Aliphatic polyamide D Mass % — — — — 50 — — 50 (weight average molecular weight Mw: 60,000) Aliphatic polyamide E Mass % — — — — — — 50 — (weight average molecular weight Mw: 30,000) Semi-aromatic polyamide Mass % — — —  5 — — — — Evaluation Weight average molecular —  5.0  5.4  6.0  5.5  6.4  6.3  6.1  4.8 result weight Mw (× 10.sup.4) of dissolved component Number average molecular —  2.2  2.3  2.4  2.3  2.5  2.5  2.4  2.2 weight Mn (× 10.sup.4) of dissolved component Tactile sensation — A A A A B B B A (squeakiness) Curl settability — A A A A A A A B

TABLE-US-00002 TABLE 1-2 Compar- Compar- Compar- Compar- ative ative ative ative Unit Example 9 Example 10 Example 11 Example 1 Example 2 Example 3 Example 4 Blending Aliphatic polyamide A Mass % — 50 50 — 100 90 70 ratio of (weight average resin molecular weight Mw: composition 90,000) Aliphatic polyamide B Mass % — — — 100 — 10 — (weight average molecular weight Mw: 50,000) Aliphatic polyamide C Mass % — — — — — — — (weight average molecular weight Mw: 160,000) Aliphatic polyamide D Mass % 50 50 — — — — — (weight average molecular weight Mw: 60,000) Aliphatic polyamide E Mass % 50 — 50 — — — — (weight average molecular weight Mw: 30,000) Semi-aromatic polyamide Mass % — — — — — — 30 Evaluation Weight average molecular —  4.7  5.9  5.2  4.5  7.7  7.3  6.6 result weight Mw (× 10.sup.4) of dissolved component Number average molecular —  2.1  2.4  2.2  1.9  2.8  2.7  2.6 weight Mn (× 10.sup.4) of dissolved component Tactile sensation — A A A A C C C (squeakiness) Curl settability — B B B C A A A

[0093] As shown in Tables 1-1 and 1-2, in each fiber for artificial hair of Examples 1 to 4 containing an aliphatic polyamide (A) having a weight average molecular weight Mw of 70,000 or more and 150,000 or less and an aliphatic polyamide (B) having a weight average molecular weight Mw of 40,000 or more and 55,000 or less, both the tactile sensation (squeakiness) and the curl settability were evaluated as A (excellent). In the fibers for artificial hair of Examples 5 to 11 not containing at least one of the aliphatic polyamide (A) and the aliphatic polyamide (B), either one of the tactile sensation (squeakiness) and the curl settability was evaluated as A (excellent), whereas the other was evaluated as B (good). In addition, in each fiber for artificial hair of Comparative Examples 1 to 4, either one of the tactile sensation (squeakiness) and the curl settability was evaluated as C (bad).

[0094] Regarding the fibers for artificial hair of Examples 12 to 15 in which a predetermined amount of flame retardant was added to the resin composition having the same blending and ratio as those of the fibers for artificial hair of Examples 1 to 4, in addition to the evaluation of the above-mentioned weight average molecular weight Mw, the tactile sensation, and the curl settability, the evaluation of processability was performed. The evaluation results are shown in Table 2. The flame retardants used for the fibers for artificial hair of Examples 12 to 15 are as follows.

[0095] Brominated epoxy resin: SRT-20000, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.

TABLE-US-00003 TABLE 2 Unit Example 12 Example 13 Example 14 Example 15 Blending Aliphatic polyamide A Mass % 27.3 45.5 63.5 40.9 ratio of (weight average resin molecular weight Mw: composition 90,000) Aliphatic polyamide B Mass % 63.5 45.4 27.3 45.5 (weight average molecular weight Mw: 50,000) Semi-aromatic polyamide Mass % — — — 4.5 Flame retardant Mass % 9.1 9.1 9.1 9.1 (brominated epoxy resin) Evaluation Weight average — 4.9 5.4 5.9 5.5 result molecular weight Mw (× 10.sup.4) of dissolved component Number average — 2.2 2.3 2.4 2.3 molecular weight Mn (× 10.sup.4) of dissolved component Tactile sensation — A A A A (squeakiness) Curl settability — A A A A Processability — B B B A

[0096] As shown in Table 2, in the fibers for artificial hair of Examples 12 to 14 containing a flame retardant in addition to the aliphatic polyamide A and the aliphatic polyamide B, the processability was evaluated as B (good) , but in the fiber for artificial hair of Example 15 further containing semi-aromatic polyamide, the processability was evaluated as A (excellent), and it was confirmed that deterioration in the processability due to the contained flame retardant can be compensated by containing the semi-aromatic polyamide.

[0097] Priority is claimed on Japanese Patent Application No. 2018-234894, filed on Dec. 14, 2018, the content of which is incorporated herein by reference.