JPH06313210A - Photochromic acrylic fiber and its production - Google Patents

Abstract

PURPOSE:To impart excellent photochromism to acrylic fiber without impairing essential function possessed by the acrylic fiber at all by using an organic photochromic compound having excellent characteristics. CONSTITUTION:The photochromic acrylic fiber consists of an acrylic polymer, an organic photochromic compound and a medium capable of preventing the organic photochromic compound from migrating as essential components 2. The character of the method for producing the photochromic acrylic fiber comprises by uniformly dissolving a mixture consisting essentially of the acrylic polymer, the organic photochromic compound and the medium capable of preventing the organic photochromic compound from migrating in a solvent for spinning and then spinning the resultant solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoreversible discolorable acrylic fiber whose color reversibly changes depending on the presence or absence of light irradiation, and a method for producing the same.

[0002]

2. Description of the Related Art Acrylic fibers are similar to natural animal hair and hair in that they have a soft texture, excellent processability, good flame retardancy, and the like. Since it has excellent properties such as having gloss, it can be used in various clothing items; interior items such as curtains and carpets; everyday items such as toys and bedding; other wigs, doll hair filaments, etc. Widely used throughout the product field.

In these commercial fields, efforts have recently been made to increase various added values, and this tendency has become remarkable especially in fields where the color effect is important.

For example, if an acrylic fiber having a new characteristic that the color reversibly changes depending on the presence or absence of light irradiation is realized, its application range is immeasurable.

Under these circumstances, various attempts have been made to color acrylic fibers by using various photochromic substances whose color reversibly changes depending on the presence or absence of light irradiation. In particular, organic photochromic compounds are abundant in types and color species, have good photoresponsiveness, have a high concentration at the time of color development, and exhibit a remarkably reversible discoloration phenomenon, and thus are useful as a coloring material for acrylic fibers. Is expected to be.

However, there is no report that a practical acrylic fiber having excellent commercial value was obtained by using such an organic photochromic compound. One of the reasons is the fact that these organic photochromic compounds are dyed on acrylic fibers. In this dyeing mechanism, it is presumed that a kind of salt-forming bond, which is observed when ordinary cationic dyes are dyed on the acrylic fiber, also occurs between the organic photochromic compound and the acrylic fiber. It However, once such a bond occurs between the two, the original photochromic property is lost from the organic photochromic compound, and the acrylic fiber remains in a colored state regardless of the presence or absence of light irradiation. For these reasons, it is not possible to employ a so-called "stock solution coloring method" in which these organic photochromic compounds are dissolved together with an acrylic polymer in a spinning dissolving agent and then spun.

On the other hand, in order to solve the above drawbacks, a method of encapsulating an organic photochromic compound in a microcapsule and coloring an acrylic fiber as a stock solution has been attempted. Since huge foreign substances (microcapsules) are present, yarn breakage occurs frequently during spinning, and it cannot be put to practical use.

Therefore, at present, as a method for applying these organic photochromic compounds to acrylic fibers, such compounds are directly or microencapsulated and mixed into various inks, paints, etc. Very limited methods such as spraying, flow coating, dipping, etc. are merely employed. However, in the acrylic fiber obtained by these methods, the ink adhesion is stopped only on the surface of the fiber, a sufficient coloring density cannot be obtained, and the physically adhered ink film is easily peeled off, and There are drawbacks such as impairing the original excellent feel of acrylic fiber, resulting in products with low commercial value or difficult commercialization.

[0009]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to use an organic photochromic compound having excellent properties and to provide an acrylic fiber with excellent properties without impairing the original function of the acrylic fiber. It is to impart photoreversible discoloration.

Another object of the present invention is to provide a novel spinning method suitable for producing such acrylic fiber.

[0011]

As a result of repeated studies in view of the problems of the prior art as described above, the present inventor has found that a medium capable of preventing dyeing of an organic photochromic compound onto an acrylic fiber (see In the following, it was found that the above object can be achieved when this medium is used as a dye transfer preventing medium for organic photochromic compounds or simply as a dye transfer preventing medium.

That is, the present invention provides a photoreversible discolorable acrylic fiber comprising an acrylic polymer, an organic photochromic compound and a dye transfer preventing medium for the organic photochromic compound as essential components.

According to the acrylic fiber of the present invention having such a constitution, the acrylic fiber can be directly colored with the organic photochromic compound, and the acrylic fiber having photoreversible discoloration property can be obtained for the first time.

The photoreversible color-changing acrylic fiber of the present invention is obtained by uniformly dissolving a mixture of an acrylic polymer, an organic photochromic compound and a dye transfer preventing medium for an organic photochromic compound as an essential component in a spinning dissolving agent, followed by a wet method. Alternatively, it can be produced by dry spinning.

Therefore, according to the present invention, unlike the case where the organic photochromic compound is used as the microcapsule-encapsulating fine particles, the yarn breakage phenomenon during spinning does not occur at all. Further, unlike the case where various inks, paints, etc. are used, the excellent properties inherent in the acrylic fiber are not impaired. As in the case of using ordinary dyes and pigments, it has been possible to carry out the undiluted solution coloring method, which is said to be an ideal coloring method for acrylic fibers, by using an organic photochromic compound. Not only does it solve the problems that the technology had, but it also offers new industrial applicability, and its profits are enormous.

As the acrylic polymer used in the present invention, those used in the production of known acrylic fibers can be used as they are. That is, not only acrylic fibers (polyacrylonitrile) containing 85% by weight or more of acrylonitrile as a monomer component but also acrylic fibers (modacrylic) having an acrylonitrile content less than that are included. As an example of the latter, more specifically, acrylonitrile 30-70% -vinyl chloride and / or vinylidene chloride 30-70% is added to a monomer component which is copolymerizable with methyl acrylate, butyl acrylate, and methacrylic acid. (Meth) acrylic acid derivatives such as methyl and ethyl methacrylate; monomers having sulfonate groups such as sodium styrene sulfonate, sodium ethylene sulfonate and sodium propane sulfonate; vinyl monomers such as vinyl acetate and styrene 1 Polymers containing up to about 10% of one or more monomers are common.

The organic photochromic compound used in the present invention is not particularly limited, and examples thereof include azobenzene compounds, thioindigo compounds, dithizone metal complexes, spiropyran compounds, spirooxazine compounds, fulgide compounds, dihydropyrene compounds, Any compounds such as spirothiopyran compounds, benzopyran compounds, naphthopyran compounds, triphenylmethane compounds, viologen compounds can be used. Among these, spiropyran-based compounds and spirooxazine-based compounds, which have good photoresponsiveness, high concentration during color development, and excellent repeatability,
Naphthopyran compounds and fulgide compounds are more preferable. These organic photochromic compounds can be used alone or in combination of two or more kinds.

Specific examples of the organic photochromic compound include the following.

1,3,3-Trimethylspiro [indolino-2,3 '-(3H) naphtho (2,1-b) (1,
4) -oxazine] 5-methoxy-1,3,3-trimethylspiro [indolino-2,3 '-(3H) naphtho (2,1-b) (1,
4) -Oxazine] 5-chloro-1-butyl-3,3-dimethylspiro [indolino-2,3 '-(3H) naphtho (2,1-b)]
(1,4) -Oxazine] 1,3,3,5-tetramethyl-9′-ethoxyspiro [indolino-2,3 ′-(3H) naphtho (2,1-
b) (1,4) -oxazine] 1,3-dihydro-1,3,3-trimethyl-6'-
(1-Piperidinyl) -spiro [2H-indole-
2,3 '-[3H] naphtho [2,1-b] [1,4] oxazine] 6'-(2,3-dihydro-1H-indol-1-yl) -1,3-dihydro-1, 3,3-Trimethyl-spiro [2H-indole-2,3 '-[3H] naphtho [2,1-b] [1,4] oxazine] 1,3,3,5,6-pentamethylspiro [indolino -2,3 '-(3H) pyrido (3,2-5) (1,4)
-Benzoxazine] 1,3,3-trimethylspiro [indolino-2,3 '
-(3H) naphtho (2,1-B) pyran] 3,3-dimethyl-3H-naphtho (2,1-b) pyran 3,3-diphenyl-3H-naphtho (2,1-b) pyran Spiro [ 2H-naphtho [1,2-b] pyran-2,2 '
-Tricyclo [3.3.1.13,7] decane] 2,5-dimethylfuryl-trimethylfulgide 2,5-dimethyl-4-nitrofuryl-trimethylfulgide Migration prevention for organic photochromic compounds used in the present invention The medium means a medium that is compatible with the above acrylic polymer, is soluble in the below-mentioned spinning dissolving agent, and is a better solvent for the organic photochromic compound than the acrylic polymer.

A medium which is not compatible with the acrylic polymer is not sufficiently incorporated into the acrylic fiber during spinning, and even if it is incorporated, it bleeds from the fiber over time after spinning, No longer shows the effect of the period. Further, those which are not sufficiently dissolved in the spinning dissolving agent may cause yarn breakage during spinning.

It is particularly important that the dye transfer prevention medium used in the present invention is a better solvent for the organic photochromic compound than the acrylic polymer. That is, since it is a good solvent for the organic photochromic compound, it exerts an action of preventing the organic photochromic compound from dyeing or transferring to the acrylic polymer.
It is considered that the dye transfer prevention medium exists in the acrylic fiber after spinning as a fine discontinuous layer uniformly dispersed in a continuous layer having a matrix structure similar to that of the acrylic polymer. Since the organic photochromic compound is carried in the discontinuous layer, it is presumed that the phenomenon of dyeing or migration to acrylic fibers is prevented.

The organic photochromic compound present in the microdiscontinuous layer comprising the dye transfer prevention medium of the present invention in an acrylic fiber is also present in another polymer in which it can exist without being dyed, such as polybutyral or polycarbonate. Alternatively, the lightfastness is significantly improved as compared to when it is present in the polyacrylic ester resin, or even more surprisingly, when it is only present in the dye transfer prevention medium. These organic photochromic compounds are known to undergo deterioration such as decomposition due to continuous light irradiation for a long period of time, or light irradiation repeatedly intermittently. The deterioration phenomenon is significantly suppressed. The suppression of the decomposition of such an organic photochromic compound is one of the great effects that has never been expected.

As the dye transfer prevention medium for organic photochromic compounds, alcohols, esters, ethers, ketones, thiols, sulfides, phenols, aromatic hydrocarbons and aliphatic hydrocarbons having a boiling point of 150 ° C. or higher are used. , Polyolefin waxes, aldehydes, nitriles, amines, azomethines, acid amides, carboxylic acids, hindered amines, hindered phenols, triazoles, (meth) acrylic acid ester resin oligomers, epoxy resin oligomers, Phenolic resin oligomers, polyester type plasticizers, metal soaps and the like can be mentioned. The boiling point of the dye transfer prevention medium is 150
The temperature is specified to be not lower than 0 ° C. in order to prevent volatilization to the outside of the fiber in the heating and stretching treatment process after spinning. These dye transfer prevention media can be used alone or in combination of two or more kinds.

Specific examples of the dye transfer preventing medium include the following: -lauryl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, ethylene glycol monoethyl ether,
Cyclohexanol, benzyl alcohol, glycerin, sorbitol, lauryl stearate, benzyl palmitate, stearyl benzoate, dioctyl phthalate, diisononyl adipate, tributyl citrate, tributyl phosphate, diphenyl ether, distearyl ketone, acetophenone, benzyl mercaptan, dilauryl-3,3 -Thiodipropionate, pentaerythritol-tetrakis- (β-lauryl-thiopropionate), nonylphenol, 2-hydroxy-4- (2-hydroxyethoxy) benzophenone,
Octylnaphthalene, paraffin, liquid paraffin, polyethylene wax, caprylaldehyde, capraldehyde, behenonitrile, naphthylstearic acid nitrile, stearylamine, distearylamine, benzylideneaniline, benzylidenestearylamine, p-isopropylbenzylideneaniline, stearic acid amide, naphthoic acid. Amide, stearic acid, benzoic acid, bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, poly [{ 6-
(1,1,3,3-tetramethylbutyl) amino-1,
3,5-triazine-2,4-diyl} {(2,2,
6,6-Tetramethyl-4-piperidinyl) imino} hexamethylene (2,2,6,6-tetramethyl-4-piperidinyl) imino] 1- (2-hydroxyethyl)-
4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2) , 2,6,6-Pentamethyl-4-piperidyl) -8'-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4.
5] Undecane-2,4-dione, 1,2,2,6,6
-Pentamethyl-4-piperidinyl-tridecyl-1,
Mixed tetraesters of 2,3,4-butanetetracarboxylic acid, tetra (1,2,2,6,6-pentamethyl-4-piperidinyl) -butanetetracarboxylate, 2,4-di-t-butylphenyl- 3 ', 5'
-Di-t-butyl-4'-hydroxybenzoate,
4,4'-methylenebis- (2,6-di-t-butylphenol), 4,4'-thiobis- (3-methyl-6-
t-butylphenol), 2 (2'-hydroxy-5 '
-Methylphenyl) benzotriazole, 2- (2'-
Hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, methyl acrylate-ethyl acrylate-2-ethylhexyl acrylate cooligomer (molecular weight about 50,000), methyl acrylate-ethyl methacrylate-butyl methacrylate Cooligomer (molecular weight about 10,000), methyl acrylate-ethyl methacrylate-acrylonitrile cooligomer (molecular weight about 8,000), resole resin cooligomer (molecular weight about 1,000), novolak resin cooligomer (molecular weight about 500), adipine Acid-propylene glycol condensate (molecular weight about 2,000), adipic acid-1,3-butylene glycol condensate (molecular weight about 5,000), zinc stearate, aluminum tristearate, ni Kell distearate, nickel butyl - dithiocarbamate, [2,2'-thiobis (4-t-octyl-phenolate] -2-ethylhexylamine - such as nickel (II).

The mixing ratio of the acrylic polymer, the organic photochromic compound, and the dye transfer inhibiting medium for the organic photochromic compound is not particularly limited, but usually 100 parts by weight of the acrylic polymer and 0.1. 01 to 10 parts by weight (preferably 0.1
.About.5 parts by weight) and about 0.1 to 30 parts by weight (preferably 0.5 to 10 parts by weight) of the dye transfer prevention medium. Particularly preferably, the dye transfer prevention medium is used in an amount of 2 times by weight or more with respect to the organic photochromic compound within the above quantitative range. Depending on the type of organic photochromic compound, the compounding amount of the organic photochromic compound is 0.
When the amount is less than 01 parts by weight, sufficient photoreversible discoloration may not be obtained, while when the amount of the organic photochromic compound and the dye transfer prevention medium is more than 40 parts by weight, after spinning, Bleed or thread breakage may occur over time.

As a dissolving agent for uniformly dissolving the above-mentioned three-component mixture as a stock solution for spinning, polar organic solvents such as acetone, dimethylformamide, dimethylsulfoxide and dimethylacetamide; thiocyanate aqueous solution, nitric acid aqueous solution, zinc chloride are used. Various aqueous solutions, such as aqueous solution, are mentioned. However, considering the solubility of the organic photochromic compound and the dye transfer prevention medium, it is preferable to use the polar organic solvent. The concentration of the three-component mixture in the spinning dope is not particularly limited, but is usually 5 to 50%.
Within the range of degrees.

The spinning stock solution contains known dyes, fluorescent dyes, ultraviolet light-emitting dyes, fluorescent brightening agents, pigments, fluorescent dyes within a range that does not impair the various properties of the photoreversible discolorable acrylic fiber after spinning. Other colorants such as pigments, phosphorescent pigments, metallic luster pigments, extender pigments, thermochromic colorants; UV absorbers, antioxidants, water repellents, flame retardants, dulling agents, matting agents, cross-linking agents, and fragrances. , Insect repellents, repellents, preservatives and the like can be added.

The photoreversible discolorable acrylic fiber of the present invention is manufactured as follows. First, an acrylic polymer, an organic photochromic compound and a dye transfer prevention medium for an organic photochromic compound in the above-mentioned spinning solubilizer,
If necessary, other additives are uniformly dissolved and dispersed to prepare a solution, and if necessary, gel-like substances, dust and the like are removed by filtration by a known filtration means such as a filter press and a candle filter. Then, the obtained spinning stock solution is discharged from the spinneret into a spinning bath (water or a dilute solution of a dissolving agent for spinning) or into hot air to form a yarn,
It is washed and dried to remove the residual dissolving agent, drawn 2 to 10 times at 100 ° C. or higher (usually around 120 ° C.), and further heat treated at around 140 ° C. to 160 ° C. to fix the yarn. If necessary, crimping can be applied with a crimper,
Alternatively, a staple may be cut into a predetermined length.

[0029]

The photoreversible color-changing acrylic fiber according to the present invention contains, in addition to the acrylic polymer and the organic photochromic compound, a dye transfer preventing medium for the organic photochromic compound as an essential component. It is possible to achieve various effects.

(A) It is possible to prevent the organic photochromic compound from being dyed or transferred to the acrylic polymer.

(B) In the production of the photoreversible discolorable acrylic fiber, it has become possible to adopt the undiluted solution coloring method which has heretofore been known as an ideal coloring method of acrylic fiber. Photoreversible discoloration can be imparted without impairing the excellent properties.

(C) The photo-reversible discoloration exhibited by the present invention has a high density at the time of color development and is not deteriorated at all even when light irradiation is repeated intermittently.

(D) Therefore, the photoreversible discolorable acrylic fiber according to the present invention is used in various clothing products; interior products such as curtains and carpets; everyday items such as toys and bedding; wigs, filaments for doll hair, etc. It can be applied to all fields of application where fibers have been used, and is particularly suitable for materials that are used in applications where color change itself enhances commercial value or where it is necessary to detect changes in physical state due to color change. Used.

[0034]

The present invention will be described in more detail with reference to the following examples. Needless to say, the present invention is not limited to these examples.

In the following, "parts by weight" will be simply referred to as "parts".

Example 1 A polymer consisting of 48 parts of acrylonitrile, 51 parts of vinyl chloride and 1 part of styrenesulfonic acid was dissolved in 300 parts of acetone to prepare a polymer solution having a polymer concentration of 25%. Then, as an organic photochromic compound in the solution,
1,3-dihydro-1,3,3-trimethyl-6'-
(1-Piperidinyl) -spiro [2H-indole-
0.5 parts of 2,3 ′-[3H] naphtho [2,1-b] [1,4] oxazine, bis (1,2,2,6,6-pentamethyl-) as a dye transfer preventing medium for organic photochromic compounds A stock solution for spinning was prepared by adding 3 parts of 4-piperidinyl) sebacate.

The spinning solution thus obtained was discharged from a spinneret having a hole diameter of 0.18 mm and a number of holes of 200 holes into a 20% acetone aqueous solution at 25 ° C. to form fibers, which was washed with water at 50 ° C.
After drying at 120 ° C. to completely remove residual acetone, and further stretching treatment at 120 ° C. 5 times, 150 ° C. × 5
A tension treatment was performed for a minute to obtain a photoreversible discolorable acrylic fiber having a single fineness of 15 denier.

The obtained acrylic fiber was colorless in a room where it was not exposed to sunlight, but exhibited a deep purple color in sunlight and under irradiation of ultraviolet rays, and this phenomenon could be reversibly repeated. Further, this photo-reversible color-changing acrylic fiber is very good in terms of texture, feel, etc., and is very good as well as ordinary acrylic fiber, and is extremely excellent in abrasion resistance, washing resistance, etc. Was excellent.

The physical properties of this photoreversible discolorable acrylic fiber were as follows.

Strength: 3.2 g / d Elongation: 35% Young's modulus: 470 kg / mm ^{2 The} above physical properties were measured as follows.

The strength and elongation were measured by holding a sample of a predetermined length (30 cm) with a chuck using a self-recording constant-speed elongation type tensile tester equipped with chucks for grasping the ends of the fibers. It was determined by pulling while applying a load and measuring the load and elongation when the sample was cut.

Young's modulus was measured using the same tester as above.
Perform the same tensile test, draw a stress-elongation curve, find the maximum stress change point (maximum tangent angle) near the origin, and change the stress per denier against the initial length of the sample. It was determined by slowing down at the rate of elongation.

Further, when the photo-reversible color change property of the fiber was examined, it was not changed from the initial reversible color change property even after 1000 times of irradiation with or without light irradiation.

Examples 2 to 10 Example 1 except that 0.5 part of the organic photochromic compound used in Example 1 and 3 parts of the dye transfer preventing medium for organic photochromic compound were replaced by those shown in Table 1. Similarly, a photoreversible discolorable acrylic fiber according to the present invention was obtained.

The obtained fiber had the same good feeling and feel as those of Example 1, and was excellent in abrasion resistance, washing resistance and the like. In addition, the photoreversible discoloration characteristic was equivalent to that of Example 1.

Table 1 collectively shows the physical properties of each fiber obtained and the hue when the color is developed by irradiation with light.

[0047]

[Table 1]

[0048]

[Table 2]

Example 11 A polymer solution obtained in the same manner as in Example 1 was treated with 1,3,3-trimethylspiro [indolino-2,3 '-(3H) naphtho (2,1-) as an organic photochromic compound.
b) (1,4) -oxazine] 0.2 part, tetra (1,2,2) as a dye transfer preventing medium for organic photochromic compounds
2,6,6-Pentamethyl-4-piperidinyl) butanetetracarboxylate 2 parts and methyl acrylate-ethyl acrylate-vinyl acetate cooligomer (molecular weight about 10,000), and the usual yellow colorant Catillon ero-SGL liquid type 0.5 part (manufactured by Hodogaya Chemical Co., Ltd.) was added and dispersed and mixed to prepare a spinning dope.

Then, as a spinneret, the hole diameter is 0.10 m.
m and a spinneret having a number of holes of 500 was obtained in the same manner as in Example 1 to obtain a photoreversible discolorable acrylic fiber having a single fineness of 3 denier using the above spinning solution, and then the fiber was pile-cutting machine. Was cut into a length of 1.5 mm to obtain short fibers for flocking.

Next, a polyacrylic ester emulsion (trademark "Nacrylic 2" was applied over the entire surface of the sponge of the laminate sheet of polyurethane foam / polyester fabric.
260J ", 75 parts by Kanebo NSC Ltd.,
Polyacrylic acid-based thickener (trademark "Iodozol KA-1
0 ", Kanebo NSC Co., Ltd. 3 parts, aqueous ammonia 2 parts and urethane type cross-linking agent (trademark" Matsumin Fixer F ", Matsui Pigment Chemicals Co., Ltd.) 5 parts ink with knife coater At a rate of 150 g / m ₂ and then the short fibers obtained above are electrostatically flocked at 150 ° C.
And heat-treated for 5 minutes to obtain a photoreversible discoloring flocked sheet.

The flocked sheet obtained was yellow in a room not exposed to sunlight, but changed to green in sunlight and under irradiation of ultraviolet rays, and such a change could be repeated any number of times.

Further, since the obtained flocked sheet uses short fibers that are undiluted (directly kneaded) with an organic photochromic compound, it has a rich color and at the same time has various physical properties, especially abrasion resistance and abrasion resistance. It was excellent in washability.

When the obtained flocked sheet is sewn to be used as a stuffed animal, for example,
The color changes reversibly when exposed to light such as sunlight, making it a unique toy that is of great interest to young children.

Example 12 After preparing a spinning dope in the same manner as in Example 11, a photoreversible discolorable acrylic fiber having a single fineness of 15 denier was produced in the same manner as in Example 1.

Then, the obtained 10 acrylic fibers were bundled into a bundle, curled according to a conventional method, cut into an appropriate length, and a sewing machine was attached to the head of the slush doll obtained by slush molding of vinyl chloride plastisol. The doll's hair was formed by stitching together.

The hair of this doll was yellow in a room without sunlight, but changed to green in sunlight and under irradiation of ultraviolet rays, and such a change could be repeated any number of times.

Comparative Example 1 An acrylic fiber was obtained in the same manner as in Example 1 except that 3 parts of the dye transfer prevention medium for organic photochromic compound was not used.

The obtained acrylic fiber always exhibited a purple color regardless of the presence or absence of light irradiation, and showed no photoreversible discoloration.

Claims (2)

[Claims] 1. A photoreversible discolorable acrylic fiber comprising an acrylic polymer, an organic photochromic compound and a dye transfer preventing medium for the organic photochromic compound as essential components. 2. A photoreversible discoloration characterized by uniformly dissolving a mixture of an acrylic polymer, an organic photochromic compound and a dye transfer preventing medium for an organic photochromic compound in a spinning solvent, and then spinning. Acrylic fiber manufacturing method.