JPH03185102A - Conjugate fiber for artificial hair and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject conjugate fiber having excellent shape stability and heat-resistance, especially dimensional stability in moisture absorbed state and heat-settability in curling, etc., by using a polyester composed mainly of butylene terephthalate unit as a core component and specifying kinetic elastic modulus and birefringence of a sheath part. CONSTITUTION:The objective conjugate fiber contains 30-90wt.% (based on the sum of the core component and the sheath component) of a polyester composed mainly of butylene terephthalate unit as the core component and a polyamide as the sheath component. The kinetic modulus (E'20) of the fiber measured at 20 deg.C and 110Hz is >=7X10<4>dyne/de, the kinetic modulus (E'150) measured at 150 deg.C is >=1.5X10<4>dyne/de, the main dispersion peak temperature (Talpha) of a mechanical loss tangent (tandelta) curve is >=130 deg.C and the birefringence of the sheath component is <=45X10<-3>. The fiber has a number of ridges and grooves having a width of 0.1-5mu and a length of 0.1-100mu, uniformly formed on the whole surface and extending in the direction of fiber axis.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a composite fiber with a thick single yarn fineness for use in artificial hair having a single yarn fineness of 10 d or more. More specifically, it is an object of the present invention to provide a composite fiber that has excellent morphological stability and heat resistance, which are important properties for artificial hair, and particularly excellent dimensional stability during moisture absorption and heat setting properties such as curl processing.

[Prior Art] Conventionally, acrylic fibers and polyamide fibers copolymerized with vinyl chloride are well known as artificial hair for wigs.

Normally, acrylic fibers copolymerized with vinyl chloride are solution-spun, and the surface of the fibers is uneven, similar to the scale-like surface of natural hair, so it has a high matting effect and is used for artificial wigs. It is often used for hair.

However, acrylic fibers copolymerized with vinyl chloride have a low melting point and poor heat resistance, so they have poor heat setting properties for wigs, etc., and the curls come off even when washed with lukewarm water. there were.

On the other hand, polyamide fibers are flexible and have good heat setting properties, but because they are melt-spun, the surface of the fibers is smooth and the single fiber fineness is thick, so the fiber surface has a strong mirror shine. As it was, it could not be used as artificial hair for wigs.

Therefore, various efforts have been made to suppress the specular gloss of polyamide-based artificial hair fibers in order to bring them closer to natural hair.

For example, JP-A-62-156308 and JP-A-62-156309 disclose that when cooling a single fiber made of a melt-spun resin in a hot water bath of at least 30°C, the cooling rate is A method for manufacturing artificial hair fibers has been proposed in which a wrinkled structure or an uneven structure is formed on the surface of the single fiber by controlling the amount of the fiber.

Furthermore, in JP-A-1-282309, in order to have wrinkle-like unevenness on the fiber surface and to improve heat-and-moisture resistance and morphological stability, copper halide, alkali metal halide, or alkaline earth metal Polyamide fibers for artificial hair having a nylon 46 polymer composition containing a halide on the fiber surface have been proposed.

[Problems to be solved by the invention] The above-mentioned JP-A-62-156308 and JP-A-62
Although the fibers obtained by the method of JP-A-156309 and the polyamide fibers proposed in JP-A-1-282309 do have a wrinkled or uneven structure on their surface, they have poor dimensional stability when wet. Moreover, due to the low modulus of polyamide fibers, they had the disadvantage of being too flexible as fibers for artificial hair.

By overcoming the above problems, the present invention has excellent morphological stability and heat resistance, which are important properties for artificial hair, and in particular, excellent dimensional stability when absorbing moisture and heat setting properties such as curling. The object of the present invention is to provide a composite fiber suitable as an artificial hair fiber having a wrinkled surface structure.

[Means and effects for solving the problem] In order to achieve the above object, the present invention has the following features: (1) polyester containing butylene terephthalate units as a core component and polyamide as a sheath component; A composite fiber having a core-sheath type composite structure, characterized in that the ratio of the core component to the core component and the sheath component is 30 to 90% by weight, and has the following characteristics (a) to (c). Thick single yarn fineness composite fiber for artificial hair having a single yarn fineness of 10d or more.

(b) The dynamic elastic modulus (E' 20) at 20°C measured at 110 Hz of the composite fiber is 7 x 104 dyne/denier or more, and the dynamic elastic modulus (E' 1 g.) at 150°C is 1
．． 5 × 10' dyne/denier or more, and the main dispersion peak temperature in the mechanical tangent modulus (tan δ) curve (
Tα) is 130°C or higher.

(b) The birefringence of the sheath portion of the composite fiber is 45×10 −3 or less.

(c) Many unevenness with a width of 0.1 to 5μ and a length of 0.1 to 100μ are uniformly distributed over the entire surface of the composite fiber, and the unevenness is formed in a long stripe shape in the fiber axis direction. .

(2) A polymer consisting essentially of highly polymerized polybutylene terephthalate with an intrinsic viscosity ([η]) of 0.80 or more forms the core, and a highly polymerized polyamide polymer with a sulfuric acid relative viscosity of 2.8 or more forms the core. In melt spinning of a core-sheath type composite fiber forming a sheath and having a ratio of core to core and sheath of 30 to 90% by weight, after being rapidly solidified by liquid cooling, passing through a fiber surface layer crystallization accelerator, A method for producing a thick single-filament fineness composite fiber for artificial hair, which is characterized in that it is then multi-stage stretched in two or more stages, then applied with an oil agent and wound up, thereby having the characteristics (a) to (c).

(a) The dynamic elastic modulus (E゛,.) of the composite fiber at 20°C measured at 110 Hz is 7 x 104 dyne/denier or more, and the dynamic elastic modulus (E'1g.) at 150°C is 1.5.
×10'dyne/denier or more, and the main dispersion peak temperature (Tα) in the mechanical tangent modulus (tanδ) curve
) is 130℃ or higher.

(b) The birefringence of the sheath portion of the composite fiber is 45×10 −3 or less.

(c) Many unevenness with a width of 0.1 to 5μ and a length of 0.1 to 100μ are uniformly distributed over the entire surface of the composite fiber, and the unevenness is formed in a long stripe shape in the fiber axis direction. , consists of.

The composite fiber of the present invention has the above-mentioned structure, but in particular, the present invention aims to improve shape stability, heat resistance, and dimensional stability upon moisture absorption, which are important properties for artificial hair that could not be achieved with conventional techniques. Improving heat setting properties such as curling and curling,
The formation of a surface wrinkle-like structure, etc. can be indicated by parameters consisting of a combination of the specified dynamic viscoelasticity of the composite fiber, the specified birefringence of the polyamide fiber portion, and the uneven structure of the fiber surface portion.

The contents and effects of each element constituting the present invention will be explained in detail below.

The polyester serving as the core component of the composite fiber of the present invention is preferably a polyester consisting essentially of polybutylene terephthalate units. This is because polybutylene terephthalate has a bending elasticity recovery close to that of natural fibers. The copolymer component may be contained to an extent that does not substantially reduce the physical and chemical properties of the polybutylene terephthalate polymer, for example, less than 10%. Copolymerization components include dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, and diphenyldicarboxylic acid;
It may also contain diol components such as ethylene oxide, propylene glycol, and butylene glycol.

In order to obtain the strength of the composite fiber of the present invention of 7.0 g/d or more, the core component polybutylene terephthalate fiber has an intrinsic viscosity [η
] has a high viscosity of 0.7 or more, preferably 0.8 or more.

On the other hand, the polyamide sheath components include polycapramide, polyhexamethylene adipamide, polytetramethylene adipamide,
It is made of common polyamides such as polyhexamethylene dodecamide and polyhexamethylene dodecamide, but polyhexamethylene adipamide-based polymers are preferred.

Similar to the polyester core component, the polyamide sheath component polymer also requires a high degree of polymerization in order to obtain a high-strength conjugate fiber, and the relative viscosity of the sulfuric acid is 2.8 or more, preferably 3.0 or more.

It is preferable to add a copper salt and other organic or inorganic compounds to the polyamide sheath component in order to improve heat resistance and weather resistance. In particular, copper salts such as iodized steel, copper acetate, copper chloride, and copper stearate are used at 30 to 500 ppm as copper, and alkali metal halides such as potassium iodide, sodium iodide, and potassium bromide are added at 0.01 to 0.5 ppm. It is preferable to contain 0.01 to 0.1% by weight of an organic or inorganic phosphorus compound.

The ratio of the polyester core component of the composite fiber of the present invention is 30 to 9
It is 0% by weight. If the polyester component is less than 30% by weight, the desired modulus and dimensional stability of the composite fiber cannot be made close to that of polyester. On the other hand, 9
When the polyester core component accounts for 0% by weight or more, the fiber becomes hard, which is not preferable as a fiber for artificial hair.

The composite fiber of the present invention is characterized by low orientation of the polyamide sheath component. That is, the birefringence of the polyamide sheath component is 45X1
The orientation of the drawn yarn is as low as 0-" or less, more preferably 42x10-" or less. If the birefringence exceeds 45 x 10-'', a composite fiber with excellent durability cannot be obtained, as it may break when subjected to repeated fatigue such as brushing.

Note that the sheath birefringence of the core-sheath composite fiber is directly measured using a transmission interference microscope.

Furthermore, the composite fiber of the present invention has a high dynamic modulus.

The dynamic elastic modulus at 20°C (E2°) measured at 110Hz is 7 x 104 dyne/denier or more, and the dynamic elastic modulus at 150°C (E'rs.) is 1.5 x 10'dyne/denier.
denier or more, and the principal dispersion peak temperature (Tα) in the mechanical tangent modulus (tanδ) curve is 130° C. or more. The dynamic elastic modulus (E'zo) at 20°C measured at 110 Hz is less than 7 x 104 dyne/denier, or the dynamic elastic modulus (E', s.) at 150°C is 1°5x
less than 104 dyne/denier, or the principal dispersion peak temperature (Tα) in the mechanical tangent modulus (tanδ) curve
) is less than 130°C, the morphological stability and heat resistance, which are important for artificial hair fibers, will be poor, and in particular the dimensional stability upon moisture absorption will be poor.

Furthermore, the fiber of the present invention has a width of 0.1 to 5 over the entire fiber surface.
A large number of unevenness having a length of 0.1 to 100μ is uniformly formed, and the unevenness is formed in a long stripe shape in the direction of the fiber axis. If the width and length of the unevenness are smaller than the respective ranges, the matting effect will be small and the appearance of artificial hair will be significantly impaired. If the width and length of the unevenness are larger than the respective ranges, the hair will feel rough to the touch, and there will be disadvantages such as hair breakage when brushing or the like.

Note that the cross-sectional shape of the fiber may be a normal round cross-section, a multi-lobed deformed cross-section, or a hollow cross-section. Further, carbon black or other pigments may be contained as a coloring agent.

The conjugate fiber of the present invention having the above-mentioned characteristics is produced by the novel method shown below.

In order to obtain the polymer physical properties of the polyester core component described above, a polymer consisting essentially of polybutylene terephthalate and having an intrinsic viscosity [η] of 0.75 or more, usually 0.85 or more is used.

The polyamide sheath component polymer has a sulfuric acid relative viscosity of 2°8 or more,
Usually, a polymer with a high polymerization degree of 3.0 or more is used.

It is preferable to use two extruder type spinning machines for melt spinning the polymer. The polyester and polyamide polymers melted by each extruder are introduced into a composite spinning bag, and spun into a composite fiber with polyester in the core and polyamide in the sheath through a composite spinning nozzle.

After spinning, the filament has a length of 20 to 30 mm placed directly under the spinneret.
After passing through a high temperature atmosphere filled with an inert gas such as nitrogen gas or superheated steam heated to a temperature of 200°C to 400°C, it is rapidly cooled in a cooling liquid of 10°C or less. The high-temperature atmosphere under the cap is created by providing a tube (hereinafter referred to as a heating tube) directly below the cap and blowing the inert gas into it.

Cooling liquids include water, aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as toluene, alicyclic hydrocarbons such as decalin,
trichlorethylene, trichlorotrifluoroethane,
A liquid inert to the polyamide, such as a halogenated hydrocarbon such as tetrachlorodifluoroethane, or a mixture thereof, is used.

The cooled filament is taken off at a speed not exceeding 50 m/min. After the cooled filament is pulled out of the liquid bath, it is passed through a cylindrical heating device filled with low-pressure steam between the solution and the take-off roll. Let it pass. The steam used for steam treatment may be saturated steam or superheated steam containing 50% or more water by weight, but the pressure is 20 to 30%.
A low pressure of 0 mmH*O is preferred. The atmospheric temperature inside the device is 60 to 160°C, and the residence time in the steam treatment cylinder is 0.01 to 160°C.
It is preferable to set the time to 1.0 seconds.

The steam treatment deviated from the conditions of the present invention, that is, the pressure was 20
Less than mmHzO, temperature less than 60℃, residence time 0.01!
If the pressure is less than 30 J), the effect of the present invention cannot be obtained;
Exceeds 0mmH*0, temperature 120℃, residence time 1.0
If the heating time exceeds seconds, the formation of a highly oriented structure in the inner layer portion will be hindered, and the effects of the present invention will not be obtained in this case as well.

The monofilament subjected to the steam treatment is taken up by a take-up roll and then continuously subjected to one or more multi-step drawing steps.

First, the first stage stretching is carried out in a heating medium heated to a temperature condition of 150°C to 210°C or in a heated gas of 150°C to 400°C.
Stretching ratio 3.0-5 while passing with residence time of seconds to 2 seconds
．． Stretch at 0x.

The filament after the first stage drawing is continuously 0.9 to 1.05
In a heating medium of 170~210℃ or 150℃~ with double stretching ratio
The film is passed through heated gas at 400°C for 0°01 to 1.5 seconds to perform two or more stages of stretching. When this second stage drawing is a relaxation heat treatment, the heat treated filament is then continuously re-stretched and a third stage drawing is carried out, and the drawing ratio in the second or third stage is usually 1.05 to 2.0. times, and the total stretching ratio is 3.5
Stretch at a high magnification so that it becomes ~6.0 times. Stretching in three or more stages is carried out in a heating medium of 180 to 220°C or 250 to 450°C.
This is carried out by passing through heated gas at a temperature of 0.01 to 3 seconds.

As the heating medium for stretching and heat treatment, a liquid inert to polyamide, such as polyethylene glycol, glycerin, and silicone, is used. Also, as a heating gas, a steam bath, N! Use a heated gas that is inert to polyamide, such as a bath.

The filament that has been subjected to the multi-stage stretching is then passed through a hot water bath or a high-temperature gas bath to remove the heating medium adhering to the filament and/or distortion caused during the stretching process, and then a finishing agent is applied and the filament is wound up. Hot water treatment usually involves passing through a hot water bath at 60°C or higher for 0°01 to 3 seconds at a stretching ratio of 0.9 to 1.0, and in the case of high temperature gas treatment, the stretching ratio is 0.0 at 200 to 400°C.
Pass for 1-3 seconds at a stretch ratio of 0.9-1.0. The finishing agent usually contains an antistatic agent and a lubricant as main components, and is applied in an amount of 0.02 to 0.5% by weight to the filament.

The polyamide monofilament of the present invention obtained by the above method has the above-mentioned physical properties and fiber structure characteristics.

Next, it will be explained based on Examples, but the main text of the present invention specification,
The fiber properties and measurement methods described in the examples are as follows. <Properties of polyester core fiber> (a) Intrinsic viscosity [η]: Dissolve the sample in an orthochlorophenol solution and measure using an Ostwald viscometer. The temperature was measured at 25°C.

<Characteristics of polyamide sheath fiber> (b) Sulfuric acid relative viscosity ηr: 0.25 g of a sample was dissolved in 25 cc of 98% sulfuric acid, and measured at 25° C. using an Ostwald viscometer.

(C) Birefringence: The average birefringence observed from the side of the fiber filament was determined by the interference fringe method using a transmission quantitative interference microscope manufactured by Carl Zeiss Jena (East Germany). Only the polyamide fiber portion was measured at 2μ intervals from the surface of the fiber to the center.

<Characteristics of composite fiber> (d) Dynamic elastic modulus (E', , E' tso) and main dispersion peak temperature (Tα): "Vibr" manufactured by Orientic Co., Ltd.

Using ``nDDV-n'', the frequency is 110Hz.

Measurements were made in an air bath at a heating rate of 3°C/min.

(e) Observation of the fiber surface using a scanning electron microscope: Using a field emission scanning electron microscope model S-800 manufactured by Hitachi, Ltd., the fiber surface was observed at an accelerating voltage of 6 KV.

(f) Tensile strength, tensile elongation: According to the definition and measurement method of JIS L1017.

(g) Bending resistance: Journal of the Japan Institute of Textile Science, 9,617. (1953), the bending elastic modulus Eb (dyne
/cm”).

(h) Dimensional stability when wet: Measure the length by taking a sample in a general shape, leaving it in a temperature and humidity controlled room at 20°C and 65% RH for more than 24 hours, and applying a load equivalent to O, Ig/d of the sample. The LO sample is treated in a constant temperature and humidity chamber at 50° C. and 95% RH for 10 hours without tension. The sample length Ll immediately after treatment was measured and expressed as a wet elongation rate obtained by the following formula.

Wet elongation rate (%) = (L, -L,)/L.

N100 [Example] Examples 1, 2 and Comparative Examples 1 to 3 Polybutylene lenticule with intrinsic viscosity [η) 0.95)
-(PBT) and 0.02% by weight of iodized steel and 0.02% by weight of potassium iodide. Hexamethylene adipamide (N) containing 1% by weight
66: Sulfuric acid (relative viscosity ηr 3.8) is melted in a 30φ kisttruder type spinning machine, guided into a composite spinning bag, and spun from a core/sheath composite spinneret into composite fibers with polybutylene terephthalate in the core and polyamide in the sheath. I put it out. The proportions of the core and sheath components were varied as shown in Table 1. The cap used had a hole diameter of 0.7 mmφ and 20 holes. Polybutylene terephthalate was melted at 285°C, polyamide was melted at 290°C, and the spinning pack temperature was set at 300°C. A 15 cm heating cylinder was attached directly below the mouthpiece, and the atmosphere inside the cylinder was heated to 290°C. The ambient temperature is the ambient temperature measured at a position 10 cm below the mouth surface and 1 cm away from the outermost thread. The filament was then heated to 80:2 of tetrachlorodifluoroethane and toluene, which was cooled to 5°C.
The mixture was cooled with a mixed solution having a weight ratio of 0. The filament pulled out from the cooling bath was treated with steam at a temperature of 90°C and a steam pressure shown in Table 1 for 0.18 seconds, and then the filament was taken up by a take-up roll at a speed of 30 m/min and then continuously heated at 180°C. The film was stretched 3.5 times in a polyethylene glycol bath having a length of 15 cm (1 stage stretching). Next, it was continuously heat-treated at 200°C in a polyethylene glycol bath with a length of 10cm at a stretching ratio of 0°95 times (
2-stage stretching). Next, continue to 210℃, length 50cm
The third stage of stretching was carried out at 1.2 times in a polyethylene glycol bath. After drawing, the filament is then heated to a bath temperature of 9.
After passing through a warm water bath of 100 cm length at 0° C. at a stretching ratio of 0.95 times, a finishing agent was applied and the film was wound up.

The fineness of the obtained filament was 50 denier, and the relative viscosity (ηr) of the nylon sheath filament was 4.0.

The physical properties of the obtained composite fiber for artificial hair are shown in Table 1.

In Examples 1 and 2 and Comparative Examples 1 and 3, countless striped irregularities with a width of about 0.05 μm and a length of about 3 μm were uniformly formed on the fiber surface layer.

Examples 1 and 2 are preferable as artificial hair because they have a softness close to that of hair and good dimensional stability when wet. On the other hand, Comparative Example 1 is hard, Comparative Example 2 has strong specular gloss, and Comparative Example 3 has poor dimensional stability when wet, so none of them are suitable as artificial hair.

(Margins below) Table 1 [Effects of the Invention] The composite fiber of the present invention has excellent morphological stability and heat resistance, and is particularly excellent in dimensional stability during moisture absorption and heat setting properties such as curling treatment. Since the surface has a wrinkled uneven structure, it has a matting effect and is suitable as a fiber for artificial hair. It has excellent thermal and wet dimensional stability especially when washed or using a dryer, and the fibers have moderate bending flexibility and excellent flexural elasticity recovery, so it provides a wig product that is close to natural hair. be able to.

Claims (2)

[Claims] (1) A composite fiber having a core-sheath type composite structure in which the core component is polyester containing butylene terephthalate units as a main component and the sheath component is polyamide, the ratio of the core component to the core component and the sheath component. A thick single yarn fineness conjugate fiber for artificial hair having a single yarn fineness of 10 d or more, characterized in that the fiber is 30 to 90% by weight and has the following characteristics (a) to (c). (b) The dynamic elastic modulus (E'_2_0) at 20°C measured at 110 Hz of the composite fiber is 7 x 10^4 dyne/denier or more, and the dynamic elastic modulus (E'_1_5_0) at 150°C is 1.5 x 10^4day
ne/denier or more, and the main dispersion peak temperature (Tα) in the mechanical tangent modulus (tan δ) curve is 130° C. or more. (b) The birefringence of the sheath part of the composite fiber is 45 x 10^-^
Must be 3 or less. (c) Many unevenness with a width of 0.1 to 5μ and a length of 0.1 to 100μ are uniformly distributed over the entire surface of the composite fiber, and the unevenness is formed in a long stripe shape in the fiber axis direction. . (2) A polymer consisting essentially of highly polymerized polybutylene terephthalate with an intrinsic viscosity ([η]) of 0.80 or more forms the core, and a highly polymerized polyamide polymer with a sulfuric acid relative viscosity of 2.8 or more forms the core. In melt spinning of a core-sheath type composite fiber forming a sheath and having a ratio of core to core and sheath of 30 to 90% by weight, after being rapidly solidified by liquid cooling, passing through a fiber surface layer crystallization accelerator, A method for producing a thick single-filament fineness composite fiber for artificial hair, which is characterized in that it is then multi-stage stretched in two or more stages, then applied with an oil agent and wound up, thereby having the characteristics (a) to (c). (b) The dynamic elastic modulus (E'_2_0) at 20°C measured at 110 Hz of the composite fiber is 7 x 10^4 dyne/denier or more, and the dynamic elastic modulus (E'_1_5_0) at 150°C is 1.5 x 10^4day
ne/denier or more, and the main dispersion peak temperature (Tα) in the mechanical tangent modulus (tan δ) curve is 130° C. or more. (b) The birefringence of the sheath part of the composite fiber is 45 x 10^-^
Must be 3 or less. (c) Many unevenness with a width of 0.1 to 5μ and a length of 0.1 to 100μ are uniformly distributed over the entire surface of the composite fiber, and the unevenness is formed in a long stripe shape in the fiber axis direction. .