Patent Application
20220095727
The present invention relates to a fiber used for artificial hair capable of being attached and detached onto head, such as wig, hair-wig, hairpiece and the like (hereinafter referred to as “artificial hair fiber”).
Patent Literature 1 discloses an artificial hair fiber prepared by threading a resin composition containing polyamide and bromine flame retardant.
[Patent Literature 1] JP 2011-246844A
In some cases, colorant of black or red is added to artificial hair fiber to color the artificial hair fiber. However, there are cases where dispersibility of the colorant in polyamide is not sufficient. Accordingly, when the resin composition is threaded into fiber using an extruder, thread breakage and clogging of the extruder filter frequently occur, resulting in decrease in productivity.
The present invention has been made by taking the afore-mentioned circumstances into consideration. The present invention provides an artificial hair fiber superior in productivity and flame retardance and also having suppressed color unevenness.
According to the present invention, an artificial hair fiber, comprising: polyamide; and 5 to 40 parts by mass of bromine flame retardant and 0.01 to 10 parts by mass of pigment processing pigment with respect to 100 parts by mass of the polyamide; wherein the pigment processing pigment comprises a colorant and a dispersant; the dispersant is contained by 20 to 80 mass % with respect to 100 mass % of total amount of the colorant and the dispersant; the dispersant comprises one or more selected from the group consisting of montanoic acid metallic salt, montanoic acid wax, polyethylene wax, and fluorine wax, is provided.
The present inventors have performed extensive research in order to solve the afore-mentioned problems. Accordingly, the present inventors have found that when artificial hair fiber satisfies the afore-mentioned composition, productivity and flame retardance become superior and color unevenness can be suppressed, thereby completing the present invention.
Hereinafter, the embodiments of the present invention will be explained.
The artificial hair fiber according to the present embodiment is an artificial hair fiber, comprising: polyamide; and 5 to 40 parts by mass of bromine flame retardant and 0.01 to 10 parts by mass of pigment processing pigment with respect to 100 parts by mass of the polyamide; wherein the pigment processing pigment comprises a colorant and a dispersant; the dispersant is contained by 20 to 80 mass % with respect to 100 mass % of total amount of the colorant and the dispersant; the dispersant comprises one or more selected from the group consisting of montanoic acid metallic salt, montanoic acid wax, polyethylene wax, and fluorine wax. The artificial hair fiber can be manufactured by melt spinning the resin composition having such composition.
Hereinafter, each of the constituents will be described in detail.
Polyamide preferably contains aliphatic polyamide, and can contain only aliphatic polyamide, or can contain aliphatic polyamide and semi-aromatic polyamide.
Aliphatic polyamide is a polyamide without aromatic ring, and n-nylon formed by ring-opening polymerization of lactams, and n,m-nylon synthesized by co-condensation polymerization reaction of aliphatic diamine and aliphatic dicarboxylic acid can be mentioned. As the aliphatic polyamide, for example, polyamide 6 and polyamide 66 can be mentioned. In terms of heat resistance, polyamide 66 is preferable.
Semi-aromatic polyamide has a skeleton in which aliphatic diamine and aromatic dicarboxylic acid are subjected to condensation polymerization. As the semi-aromatic polyamide, polyamide 6T, polyamide 9T, polyamide 10T, and modified polyamide 6T, modified polyamide 9T, and modified polyamide 10T which are based on polyamide 6T, polyamide 9T, and polyamide 10T with monomer for modification being copolymerized.
The weight average molecular weight (Mw) of the polyamide is 6.5×104 to 15×104 for example.
When Mw is 6.5×104 or more, the dripping-resistant characteristics become especially superior. On the other hand, when Mw exceeds 15×104, the melt viscosity of the material increases, thereby decreasing the workability when the material is threaded. Accordingly, Mw is preferably 15×104 or lower. When the balance between the dripping-resistant characteristics and workability is taken into consideration, Mw is more preferably 7×104 to 12×104.
Addition amount of the bromine flame retardant is 5 to 40 parts by mass with respect to 100 parts by mass of the polyamide, and is preferably 10 to 30 parts by mass. When the addition amount is in such range, the balance of the effect of providing dripping-resistant characteristics and workability is superior.
As the bromine flame retardant, brominated phenol condensation product, brominated polystyrene resin, brominated benzyl acrylate flame retardant, brominated epoxy resin, brominated phenoxy resin, brominated polycarbonate resin and bromine-containing triazine compound can be mentioned. Considering the balance of dripping-resistant characteristics, workability, and transparency (clarity) of the raw thread, brominated epoxy resin or brominated phenoxy resin containing the structural formula shown in (1) below are preferred.
Processing pigment contains colorant and dispersant. The processing pigment can be prepared by mixing the colorant and dispersant. The amount of the processing pigment added is 0.01 to 10 parts by mass with respect to 100 parts by mass of polyamide, preferably 0.1 to 5 parts by mass, and further preferably 0.2 to 2 parts by mass. When the addition amount is in the afore-mentioned range, balance between the coloring characteristics and workability is superior.
The colorant is pigment, dye and the like. By adding the colorant beforehand, a pre-colored fiber (so-called “spun-dyed fiber”) can be obtained.
As the colorant, black colorant, red colorant, yellow colorant, purple colorant and the like can be mentioned. Among these, one or a plurality of colorants can be used.
As the black colorant, Pigment Black 7, Solvent Black 7 and the like can be mentioned. Pigment Black 7 is preferable in terms of flame retardance.
As the red colorant, Pigment Red 149, Pigment Red 177, Solvent Red 179 and the like can be mentioned. Pigment Red 149 is preferable in terms of flame retardance.
As the yellow colorant, Pigment Yellow 147, Solvent Yellow 163, Solvent Yellow 21, Pigment Yellow 184 and the like can be mentioned. Pigment Yellow 147 or Solvent Yellow 163 are preferable in terms of flame retardance.
As the purple colorant, Pigment Violet 19, Pigment Violet 29 and the like can be mentioned for example. Pigment Violet 19 is preferable in terms of flame retardance.
The dispersant serves as dispersibility enhancer of the colorant in the polyamide. The dispersant is one or more of montanoic acid metallic salt, montanoic acid wax, polyethylene wax, and fluorine wax. Montanoic acid metallic salt is preferable. When montanoic acid metallic salt is used, thread breakage resistance becomes especially superior. As the montanoic acid metallic salt, calcium montanate, zinc montanate, sodium montanate and the like can be mentioned. The dispersant is especially preferably calcium montanate. When calcium montanate is used, occurrence of color unevenness is especially suppressed.
When the total amount of the colorant and the dispersant is 100 mass o, the amount of dispersant is 20 to 80 mass o, preferably 30 to 70 mass %. When the amount of dispersant is too small, long-running performance is deteriorated, and when the amount of dispersant is too large, thread breakage resistance is deteriorated.
The resin composition structuring the artificial hair fiber can, as necessary, contain additives such as flame retardant auxiliary, organic fine particle, heat resistant agent, light stabilizer, fluorescent agent, antioxidant, antistatic agent, plasticizer, lubricant and the like.
Hereinafter, one example of the manufacturing process of the artificial hair fiber will be explained.
The manufacturing method of the artificial hair fiber according to one embodiment of the present invention comprises a melt spinning step, drawing step, and a heat treatment step.
Hereinafter, each step is explained in detail.
In the melt spinning step, the resin composition is subjected to melt spinning to manufacture undrawn fiber. In particular, the afore-mentioned resin composition is first melt and kneaded. As the apparatus for melting and kneading, various general mixing and kneading machine can be used. As the mixing and kneading machine, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, a kneader and the like can be mentioned for example. Among these, the twin-screw extruder is preferable in terms of adjustment of kneading degree and simplicity of operation. The artificial hair fiber can be manufactured by performing melt spinning of normal melt spinning method under appropriate temperature conditions depending on the type of polyamide used.
The temperature of the melt spinning apparatus such as extruder, mouth piece, and gear pump as necessary are set, for example, to 270 to 310° C. to perform melt spinning. Subsequently, the fiber is cooled in a water tank filled with water for cooling, and then while controlling the fineness of fiber, the hauling speed is adjusted, thereby obtaining an undrawn fiber. The temperature of the melt spinning apparatus can be arbitrarily adjusted depending on the content of the resin composition. Further, other than using the water tank, cooling can be conducted by performing spinning with cold-wind. Temperature of cooling water tank, temperature of cold-wind, cooling time, and hauling speed can be arbitrarily adjusted by jetting amount and number of holes in the mouth piece.
The fineness of single fiber of the artificial hair fiber according to the present embodiment is preferably 20 to 100 decitex, more preferably 35 to 80 decitex. In order to achieve such fineness of single fiber, fineness of fiber immediately after the melt spinning step (undrawn fiber) is preferably adjusted to 300 decitex or lower. When the fineness of the undrawn fiber is small, the drawing magnitude for obtaining artificial hair fiber with low fineness can be small, thereby suppressing occurrence of gloss in the artificial hair fiber after drawing processing. Accordingly, maintaining a condition ranging between medium gloss to seven part gloss tends to be easy.
The cross-sectional area of the nozzle used in the melt spinning is not particularly limited, and can be 0.1 to 2 mm2. Further, when quality such as curling characteristics for usage in artificial hair is taken into consideration, it is preferable that the material is melt and flown from a nozzle in which a cross-sectional area of one nozzle hole is 0.5 mm2 or less. When the cross-sectional area of one nozzle hole is 0.5 mm2 or less, the tension required for obtaining undrawn fiber or heat drawn fiber having low fineness can be maintained low, thereby suppressing residual strain. Accordingly, quality such as curl retention property hardly degrade.
When performing melt spinning, the nozzle pressure is preferably 50 MPa or lower. When the nozzle pressure is such, the load applied to the thrust portion of the extruder becomes low, thereby tending to show less occurrence of defects in the extruder. Accordingly, resin leakage from the connecting portion of turn head, die and the like is less likely to occur.
The mold used for melt spinning can be a spinning mold with a nozzle of which shape being one or more selected from the group consisting of circle, cocoon-shape, Y-shape, H-shape, and X-shape. Since these molds do not have complex shapes, it is easy to produce fibers having a shape of the mold. In addition, fibers made using these molds can retain their shape easily and are relatively easy to process.
In the drawing step, the undrawn fiber obtained is drawn by a drawing magnitude of 150 to 500%, thereby manufacturing a drawn fiber. With such drawing, a drawn fiber having low fineness of 100 decitex or lower can be obtained, and tensile strength of the fiber can also be improved. The drawing processing can be performed by two-step method in which the undrawn fiber is first wound to a bobbin, and then the drawing is performed in a step separate from the melt spinning step. The drawing processing can be performed also by a direct spinning-drawing method in which the undrawn fiber is not wound to a bobbin and is sequentially drawn after the melt spinning step. Further, the drawing processing is performed by a one-step drawing method in which the fiber is drawn to the desired drawing magnitude in one step, or is performed by a multiple-step drawing method in which the fiber is drawn to the desired drawing magnitude by two or more steps. Heater used in the heat drawing processing can be a heating roller, a heat plate, a steam jet device, and a hot water tank. These heaters can be used in combination. The drawing magnitude is preferably 200 to 400%. When the drawing magnitude is sufficiently large, fiber strength tends to be achieved easily, and when the drawing magnitude is sufficiently small, thread breakage during drawing processing tends to be suppressed.
The temperature during the drawing processing is preferably 90 to 120° C. When the temperature during the drawing processing is too low, the fiber strength tends to become weak and thread breakage tends to occur easily. When the temperature of the drawing processing is too high, the texture of the fiber obtained tends to be close to those of plastic, and feels slippery.
In the heat treatment step, the drawn fiber is subjected to heat treatment at a heat treatment temperature of 155° C. or higher. With this heat treatment, thermal shrinkage of the drawn fiber can be suppressed. The heat treatment can be performed following the drawing processing, or can be performed some time after the drawn fiber is wound. The heat treatment temperature is preferably 160° C. or higher, more preferably 170° C. or higher, and further preferably 180° C. or higher. The upper limit of the heat treatment temperature is not particularly limited, and is, for example, 220° C.
Examples of the artificial hair fiber according to the present invention will be described in detail by comparing with the Comparative Examples. Further, the present invention will be described in more detail based on the Examples, however, the present invention is not limited to these Examples.
Polyamide dried so as to have a moisture content of less than 1000 ppm, flame retardant, and processing pigment were blended so as to have a blending ratio of Examples and Comparative Examples shown in Table 1 to Table 4. The blended material was kneaded using a twin-screw extruder having ϕ 30 mm, thereby obtaining raw material pellets for spinning.
Subsequently, the pellets were dehumidified and dried so as to have a moisture content of less than 1000 ppm, and then the pellets were spun using a single-screw melt spinning machine having ϕ 40 mm. The molten resin discharged from the die having a hole diameter of 0.5 mm was cooled by allowing the resin to go through a water tank of approximately 30° C. The jetting amount and the winding speed were adjusted so as to obtain undrawn fiber having a desired fineness. The melt spinning machine was constituted by arranging the screw, the wire mesh filter, and the die in this order. The pellets were heated and melt by the screw to give a molten resin composition, and then the molten resin composition was filtered through the filter, followed by discharging from the die. The temperature of the die was set to 290° C.
The undrawn fiber thus obtained was drawn at 100° C., followed by annealing at 150 to 200° C., thereby obtaining artificial hair fiber having a desired fineness. The drawing magnitude was 3 times, and the relaxation rate during annealing was 0.5 to 3%. The relaxation rate during annealing is a value obtained by (rotation speed of winding roller during annealing)/(rotation speed of feeding roller during annealing).
The artificial hair fiber thus obtained was evaluated for color unevenness, transparency (clarity), flame retardance, thread breakage resistance, and long-running performance, in accordance with the evaluation method and criteria described herein. The results are shown in Table 1 to Table 4.
As the materials mentioned in Table 1 to Table 4, the followings were used.
polyamide 66 (weight average molecular weight 90000, available from Du Pont, Zytel 42A)
polyamide 6 (weight average molecular weight 90000, available from Denka Company Limited)
brominated epoxy (available from Sakamoto Yakuhin Kogyo Co., Ltd., SRT-20000)
calcium montanate (available from NITTO KASEI KOGYO K.K.)
zinc montanate (available from NITTO KASEI KOGYO K.K.)
sodium montanate (available from NITTO KASEI KOGYO K.K.)
montanoic acid ester wax (available from Clariant Japan K. K., Licowax E)
polyethylene wax (available from Clariant Japan K. K., Licowax PE520)
montanoic acid wax/fluorine wax blended product (available from Clariant Japan K. K., WaxCompositeG431L)
calcium stearate (available from NITTO KASEI KOGYO K.K.)
calcium 12-hydroxystearate (available from NITTO KASEI KOGYO K. K.)
Pigment Black 7 (available from Denka Company Limited)
Solvent Black 7 (available from Orient Chemical Industries Co., Ltd.)
Pigment Red 149 (available from Clariant Japan K. K.,)
Pigment Red 177 (available from BASF SE)
Solvent Red 179 (available from Orient Chemical Industries Co., Ltd.)
Pigment Yellow 147 (available from BASF SE)
Solvent Yellow 163 (available from BASF SE)
Solvent Yellow 21 (available from Orient Chemical Industries Co., Ltd.)
Pigment Yellow 184 (available from BASF SE)
Pigment Violet 19 (available from BASF SE)
Pigment Violet 29 (available from BASF SE)
The evaluation method and criteria for each of the evaluation items in Table 1 to Table 4 are as follows.
The color unevenness was evaluated by using samples prepared with artificial hair fiber of Examples and Comparative Examples bundled to have 200 mm length and 1.0 g weight. The samples were evaluated by artificial hair fiber engineers (5 or more years of experience) by visual observation in accordance with the following criteria.
A : No color unevenness observed.
B : Scarce color unevenness observed, no problem for usage as artificial hair fiber.
C : Apparent color unevenness observed at a glance, cannot be used as artificial hair fiber.
The transparency (clarity) was evaluated by using samples prepared with artificial hair fiber of Examples and Comparative Examples bundled to have 200 mm length and 1.0 g weight. The samples were evaluated by artificial hair fiber engineers (5 or more years of experience) by visual observation in comparison with human hair, in accordance with the following criteria.
A: Transparency (clarity) similar to human hair observed.
B: Difference observed when compared with human hair, however, transparency (clarity) close to human hair observed in general.
C: Apparent cloudiness observed at a glance, difference from human hair observed.
The flame retardance was evaluated by using samples prepared as follows. Artificial hair fiber were cut into a length of 30cm, thereby preparing a fiber bundle sample having a weight of 2g containing a number of fibers. One end of the fiber bundle was fixed to allow the fiber bundle to hang vertically, and the lower end was allowed to contact with a flame having a length of 20mm for 5 seconds. The flame propagation period after taking away the flame was measured. Evaluation was performed with the following criteria. The results are shown as the average of three measurement results.
A: Flame propagation period was less than 5 seconds.
B: Flame propagation period was 5 seconds or more and less than 10 seconds.
C: Flame propagation period was 10 seconds or more.
The thread breakage resistance was evaluated as follows. Occurrence of thread breakage was visually observed during melt spinning until the undrawn fiber was obtained. Evaluation was made in accordance with the following criteria.
A: Time of thread breakage was 1 time or less/1 hour.
B: Time of thread breakage was 2 to 3 times/1 hour.
C: Time of thread breakage was 4 times or more/1 hour.
The long-running performance was evaluated by the time spinning can be performed continuously without changing the filter.
A: 48 hours or longer
B: 24 to 48 hours
C: less than 24 hours
All of the Examples showed evaluation result of A or B in all of the evaluation items of color unevenness, transparency (clarity), flame retardance, thread breakage resistance, and long-running performance.
On the other hand, all of the Comparative Examples showed evaluation result of C in at least one of the evaluation items. In particular, in Comparative Examples of 1 to 2, 5 to 6, 9 to 10, and 13 to 14, in which the dispersant other than montanoic acid metallic salt was used, the thread breakage resistance was not superior. Further, in Comparative Examples 3, 7, 11, and 15 in which the ratio of dispersant was too small, the long-running performance was not superior. In Comparative Examples 4, 8, 12, and 16 in which the ratio of dispersant was too large, the thread breakage resistance was not superior.
Among the Examples, when montanoic acid metallic salt was used as the dispersant, the thread breakage resistance was especially superior compared to cases where a substance other than the montanoic acid metallic salt was used as the dispersant. Further, when calcium montanate was used, the color unevenness was especially small compared to cases where a substance other than the calcium montanate was used.
Further, regarding the black colorant, the flame retardance was superior when Pigment Black 7 was used. Regarding the red colorant, the flame retardance was superior when Pigment Red 149 was used. Regarding the yellow colorant, the flame retardance was superior when Pigment Yellow 147 or Solvent Yellow 163 was used. Regarding the purple colorant, the flame retardance was superior when Pigment Violet 19 was used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-027336 | Feb 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/005496 | 2/13/2020 | WO | 00 |
