JPS6324086B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyester fibers.
More particularly, the present invention relates to a method for producing porous polyester fibers having special micropores and exhibiting improved color depth and clarity when colored. Polyester is widely used as a synthetic fiber because it has many excellent properties. However, compared to natural fibers such as wool and silk, cellulose fibers such as rayon and acetate, and acrylic fibers, polyester fibers lack the depth of color when colored, resulting in inferior color development and clarity. There is. Conventionally, attempts have been made to improve dyes, chemically modify polyester, etc. in an attempt to overcome this drawback, but none of them have been sufficiently effective. In addition, methods have been proposed in which a transparent thin film is formed on the surface of polyester fibers, and a method in which plasma irradiation at 80 to 500 mA·sec/cm ² is applied to the surface of a woven or knitted fabric to form fine irregularities on the fiber surface. However, even with these methods, the effect of improving the depth of color is insufficient, and in addition, the transparent thin film formed on the fiber surface easily falls off when washed, etc., and its durability is insufficient. In the method of applying plasma irradiation, unevenness does not occur on the surface of the fiber in the part of the fiber that is in the shadow of the irradiated surface, so the smooth fiber surface is There is a drawback that color spots appear on the skin. On the other hand, as a method for imparting irregularities to the surface of polyester fibers, fibers made of polyoxyethylene glycol or polyester blended with polyoxyethylene glycol and a sulfonic acid compound are treated with an alkaline aqueous solution to form wrinkles arranged in the fiber axis direction. A method for producing hygroscopic fibers in which micropores are formed on the fiber surface, or polyester fibers prepared by adding fine particles of an inert inorganic substance such as zinc oxide or calcium phosphate to a polyester reaction system are treated with an alkaline aqueous solution. A method for producing hygroscopic fibers has been proposed in which fine pores are formed by eluting inorganic fine particles. however,
In the fibers obtained by these methods, no effect of improving the depth of color is observed, and on the contrary, a decrease in visual density is observed. That is, in these methods, if the treatment with the alkaline aqueous solution is not sufficient, no effect of improving the color depth is observed at all, and when the treatment with the alkaline aqueous solution is sufficient, the color depth is not improved, The visual density decreases, probably due to the diffuse reflection of light by the micropores.
Even if the fibers are dyed in a deep color, they look whitish, and furthermore, the strength of the obtained fibers is significantly reduced and they become easily fibrillated, making them unsuitable for practical use. In addition, fibers made of polyester containing inorganic fine particles such as silica with a particle size of 80 mμ or less are subjected to an alkali weight reduction treatment to give irregular irregularities of 0.2 to 0.7 μm on the fiber surface, and 50 to 50 μm in diameter within these irregularities.
A method has been proposed to improve the depth of color by creating fine irregularities of 200 mμ. However, even with this method, the effect of improving the depth of color is insufficient, and on top of that, perhaps due to the extremely complicated shape of the unevenness, the unevenness is destroyed and destroyed by external physical effects such as friction. There are disadvantages in that the damaged portions are significantly discolored or have a difference in gloss compared to other undestructed portions, and furthermore, they easily become fibrillated. The inventor of the present invention has conducted extensive research in an attempt to provide polyester fibers that are free from the above-mentioned drawbacks and have excellent color depth and clarity by adding micropores to polyester fibers. Visible light rays can be removed by alkali treatment of polyester fibers obtained by melt-spinning polyester synthesized by adding a specific amount of metal compound to the polyester reaction system without reacting the phosphorus compound with a specific amount of metal compound in advance. It is possible to form irregularities that are smaller than the size of the wavelength on the entire surface of the fiber, and by doing so, when colored, the color is excellent in depth and clarity, and discoloration due to friction is sufficiently small, making it resistant to fibrillation. They discovered that polyester fibers with excellent properties could be obtained, and proposed this method earlier. In the course of such studies, the present inventors have come to the important finding that as the size of the irregularities formed on the fiber surface becomes finer, both the color improvement effect and the fibrillation resistance improve. Based on this knowledge, the present inventor has conducted extensive studies on ways to impart even finer irregularities to the surface of polyester fibers, and as a result, has melt-spun a polyester composition containing a specific imide compound that is compatible with polyester. It has been found that by subjecting the obtained polyester fibers to an alkali treatment, it is possible to improve the uneven morphology of the fiber surface and improve the color improvement effect. The present invention was developed based on this knowledge, and
It is completed. That is, in the present invention, 0.1 to 0.1 to 100 parts by weight of an imide compound satisfying the following conditions (1) to (4) is added to 100 parts by weight of aromatic polyester.
30 parts by weight of a polyester composition is melt-spun, and the resulting polyester fiber is treated with an aqueous solution of an alkaline compound to elute 2% by weight or more of the fiber. It is the law. (1) Substantially stable under the melting conditions of the aromatic polyester, non-reactive with the polyester, and compatible with the polyester. (2) Phase separation from the polyester does not occur when the polyester composition is cooled and solidified. (3) Melting point is 100℃ or higher. (4) Molecular weight is 1000 or less. The aromatic polyester used in the present invention is
The main acid component is aromatic dicarboxylic acid, and the aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, and diphenol dicarboxylic acid. Examples include siethanedicarboxylic acid, methyl terephthalic acid, and methyl isophthalic acid. In addition, glycol components include ethylene glycol,
Aliphatic glycols such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, etc.
Alicyclic glycols such as 1,4-cyclohexanedimethanol, hydroquinone, methylhydroquinone, butylhydroquinone, amylhydroquinone, resorcinol, 2,2-bis(4-
hydroxyphenyl) propane [bisphenol A], 1,1-bis(4-hydroxyphenyl)
Cyclohexane [bisphenol Z], bis(4
Aromatic dihydroxy compounds such as -hydroxyphenyl) ether and the like can be used. In addition to the above-mentioned dicarboxylic acid component and glycol component, an oxycarboxylic acid component may be used, and examples of the oxycarboxylic acid include oxybenzoic acid, oxynaphthoic acid, and β-hydroxyethoxybenzoic acid. In addition to the above components, the aromatic polyester used in the present invention contains a small proportion (usually 10 mol% or less of the total acid components) of aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and hexahydroterephthalic acid. It may contain alicyclic dicarboxylic acids such as and 5-sodium sulfoisophthalic acid, and a small amount (usually 10% by weight or less) of polyoxyalkylene glycol may be copolymerized. Furthermore, within the range where the aromatic polyester is substantially linear (usually 1 mol% or less), trimellitic acid,
A polycarboxylic acid such as pyromellitic acid, a polyol such as glycerin, trimethylolpropane, pentaerythritol, etc. may be copolymerized. Among the above aromatic polyesters, the following general formula

[Formula] (m represents an integer of 2 to 6) A polyester mainly containing repeating units is preferred, and polyethylene terephthalate and polybutylene terephthalate are particularly preferred. Such aromatic polyester may be synthesized by any method. For example, in the case of polyethylene terephthalate, usually terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are transesterified. a first step reaction of producing a glycol ester of terephthalic acid and/or a low polymer thereof by reacting with an oxide;
It is produced by a second stage reaction in which the reaction product of the first stage is heated under reduced pressure to perform a polycondensation reaction until a desired degree of polymerization is achieved. In the present invention, the imide compound blended into the aromatic polyester is (1) substantially stable and non-reactive with the aromatic polyester under the melting conditions of the aromatic polyester, for example at a temperature of +20° C. to the melting point of the polyester; In addition, it is necessary that when blended with the aromatic polyester, it does not cause phase separation and is uniformly compatible with the aromatic polyester. Here, "substantially stable and non-reactive with aromatic polyesters" means that it does not decompose itself or decompose aromatic polyesters or react with aromatic polyesters. . Furthermore, (2) even when the homogeneous melt obtained by melt-mixing the aromatic polyester and the low-molecular-weight compound is cooled and solidified, the imide compound does not undergo phase separation with the aromatic polyester and is uniformly compatible with the aromatic polyester. It is necessary to be able to maintain the original state. this is,
For example, when the above-mentioned homogeneous transparent melt is cooled at a cooling rate sufficient to give an amorphous solid, a homogeneous transparent solid is obtained, or phase separation occurs to give an opaque solid. This can be easily determined by looking at the Furthermore, the imide compound has (3) a melting point of 100°C or higher,
and (4) the molecular weight must be 1000 or less. When the melting point of the imide compound is 100℃ or less,
When melt-mixed with an aromatic polyester, it significantly lowers the secondary transition point of the aromatic polyester, making it difficult to handle during molding. The imide compound used in the present invention may be one that satisfies the above conditions (1) to (4), but in addition, from the viewpoint of preventing volatilization during melt mixing, the imide compound has a boiling point at normal pressure.
A temperature of 250°C or higher, particularly 300°C or higher is preferably used. The imide compound used in the method of the present invention may be one that satisfies the above conditions, but for example, the following formula () (Here, A ¹ is a divalent aromatic residue or a chain or cyclic aliphatic residue, which may be substituted; R ¹ is an n-valent aromatic residue or a chain or cyclic aliphatic residue. It is an aliphatic residue and may be substituted; n is 1 or 2. However, the imide ring in the above formula is 5 or 6 members.) An imide compound represented by the following formula () (Here, A ² is a tetravalent aromatic residue and may be substituted; R ² is a monovalent chain or cyclic aliphatic residue and may be substituted. However, , imide rings in the above formula are 5 or 6 members
member. ) can be listed. As a compound of the above formula (), the above formula ()
A compound in which at least one of A ¹ or R ¹ is an optionally substituted aromatic residue, particularly a compound in which A ¹ is a divalent optionally substituted aromatic residue, is preferably used. . Further, as the compound of the above formula (), a compound in which R ² in the above formula () is a monovalent, optionally substituted aliphatic residue is preferably used. In the above general formula (), the divalent aromatic residue representing A ¹ can include, for example, a 1,2-phenylene group, 1,2-, 2,3- or 1,8-naphthylene group. As the divalent aliphatic residue, for example, a linear alkylene group such as ethylene or trimethylene, or a cycloalkylene group such as 1,2-cyclohexylene group can be mentioned. These groups may be substituted with a substituent that is non-reactive with respect to the aromatic polyester. Examples of such substituents include lower alkyl groups such as methyl and ethyl, lower alkoxy groups such as methoxy and ethoxy, halogen atoms such as chlorine and bromine,
Examples include cyclohexyl which may be substituted with a nitro group, phenyl group, phenoxy group, and methyl group. The n-valent (n=1 or 2) aromatic residue representing R ¹ is, for example, a phenyl group, a naphthyl group, or a

A monovalent aromatic residue such as the group [Formula] (where Z is -O-, -SO ₂ - or -CH ₂ -), or a 1,2-phenylene group, 1,2-, 2 , 3- or 1,8-naphthylene group or formula

[Formula] (where Z is -O-, -SO ₂ - or -CH ₂ -)
Examples of n-valent (n=1 or 2) aliphatic residues include methyl, ethyl, butyl, hexyl,
1 to 18 carbon atoms such as heptyl, octyl, nonyl, decyl, dodecyl, myricityl, stearyl
or a 5- or 6-membered cyclic alkyl group such as cyclohexyl or cyclopentyl, or a carbon number of 2 to 12 such as ethylene, trimethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, dodecamethylene.
a linear alkylene group, a cyclic alkylene group such as a 1,3- or 1,4-cyclohexylene group, or

The group of [Formula] can be listed. These groups representing R ¹ may be substituted with the same substituents as described for A ¹ . In the above formula (), the tetravalent aromatic residue representing A ² is, for example,

【formula】

【formula】

【formula】

[Formula] or

Monocyclic, condensed ring, or polycyclic tetravalent aromatic groups represented by the formula: (Z is the same as defined above) can be listed as preferred. The tetravalent chain or cyclic aliphatic residue representing R ² may be a chain alkyl group having 1 to 18 carbon atoms or a 5- or 6-membered cyclic alkyl group as exemplified for R ¹ in the above formula (). Alkyl groups can be mentioned. The groups exemplified above for A ² and R ² may be substituted with the same substituents as described for A ¹ . Examples of the imide compound represented by the above formula () include N-methyl phthalimide, N-ethylphthalimide, N-butylphthalimide,
N-ethyl-1,8-phthalimide, N-butyl-1,8-naphthalimide, etc.; as compounds when n=2, N,N'-ethylenebisphthalimide, N,N'-tetramethylenebisphthal imide, N,N'-hexamethylene bisphthalimide, N,N'-octamethylene bisphthalimide, N,N'-decamethylene bisphthalimide, N,N'-dodecamethylene bisphthalimide, N,N'-neopentylene bisphthalimide, N,N'-tetramethylene bis(1,8-
naphthalimide), N,N'-hexamethylenebis(1,8-naphthalimide), N,N'-octamethylenebis(1,8-naphthalimide),
N,N'-decamethylene bis(1,8-naphthalimide), N,N'-dodecamethylene bis(1,
8-naphthalimide), N,N'-dodecamethylene bissuccinimide, N,N'-dodecamethylene bishexahydrophthalimide, N,N'-
1,4-cyclohexylene bisphthalimide,
1-phthalimido-3-phthalimidomethyl-3,5,5-trimethylcyclohexane, 4,
4′-bisphthalimide diphenyl ether,
3,4'-bisphthalimido diphenyl ether, 3,3'-bisphthalimido diphenyl sulfone, 4,4'-bisphthalimido diphenyl sulfone, 4,4'-bisphthalimido diphenyl Methane, etc. can be listed. Examples of the imide compound represented by the above formula () include N,N'-diethylpyromellitimide, N,N'-dibutylpyromellitimide, N,
N'-dihexylpyromellituimide, N,N'-
Dioctylpyromellittimide, N,N'-didecylpyromellittimide, N,N'-dicyclohexylpyromellittimide, N,N'-bis(3,
3,5-trimethylcyclohexyl)pyromellituimide, N,N'-diethyl-1,4,5,8
- Naphthalene tetracarboxylic acid 1,8-, 4,5
- You can list diimide, etc. The imide compounds represented by the above formulas () and () can be easily produced from the corresponding acid anhydrides and organic amines by known methods. In the present invention, first, aromatic polyester
A polyester composition is obtained by blending 0.1 to 30 parts by weight of an imide compound with 100 parts by weight.
If the blending amount of the imide compound is less than 0.1 part by weight, the color depth and clarity of the final polyester fiber obtained will be insufficient, and as this amount is increased, the color depth and clarity will increase. When the amount exceeds 30 parts by weight, no significant improvement is achieved, and the abrasion resistance and durability deteriorate on the contrary, and the melt viscosity of the resulting composition decreases significantly, making melt spinning difficult. The blending amount of the imide compound is more preferably 3 to 20 parts by weight. A composition consisting of an aromatic polyester and an imide compound can be prepared by adding the imide compound to the polyester raw material or the reaction mixture at any stage until the synthesis of the polyester is completed, for example, after completing the synthesis of the polyester. Alternatively, it may be a simple dry blend of polyester chips and an imide compound, or it may be a mixture obtained by melt-mixing the polyester chips and an imide compound in advance in a melt extruder. Also,
It is also preferable to use a compound in which an imide compound obtained by heating and melting an imide compound above the melting point is mixed with an aromatic polyester chip and then cooling the mixture to below the melting point, and the imide compound is adhered to the surface of the aromatic polyester chip. In the above composition, optional additives,
For example, it may contain catalysts, oxidation stabilizers, ultraviolet stabilizers, flame retardants, optical brighteners, matting agents, colorants, etc., and also suppresses increases in the degree of polymerization or decreases in the degree of polymerization during melt spinning. From the perspective of 2,2′-bis(2-
Chain extenders such as oxazoline) and 2,2'-bis(3,1-benzoxazin-4-one) can also be preferably incorporated. There is no need to employ any special method for melt-spinning the polyester composition obtained in this manner to form fibers, and any ordinary melt-spinning method for polyester fibers may be employed. The fibers spun here may be solid fibers having no hollow portions or hollow fibers having hollow portions. Further, the outer shape and the shape of the hollow portion in the cross section of the fiber to be spun may be circular or irregular. In order to remove a part of the polyester fiber obtained in this way and make it into a porous polyester fiber, after subjecting it to stretching heat treatment or false twisting as necessary, or after making it into a fabric, it is treated with an aqueous solution of an alkaline compound. This can be easily done by processing. Examples of the alkali compound used here include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate, and the like. Among these, sodium hydroxide and potassium hydroxide are particularly preferred. The concentration of such an aqueous solution of an alkali compound varies depending on the type of alkali compound, processing conditions, etc., but is usually preferably in the range of 0.01 to 40% by weight, particularly
A range of 0.1 to 30% by weight is preferred. The processing temperature is preferably in the range of room temperature to 100°C, and the processing time is 1 minute to 1 minute.
It is usually carried out for a period of 4 hours. Further, the amount of the alkali compound eluted and removed by treatment with the aqueous solution should be in the range of 2% by weight or more based on the weight of the fiber. By treating with an aqueous solution of an alkaline compound in this way, a large number of special micropores can be formed on the fiber surface and in its vicinity.
It exhibits excellent color depth when dyed. In addition, the imide compound remaining in the polyester fiber obtained by the method of the present invention can be extracted and removed by treating the polyester fiber with an organic solvent as necessary. Examples of such organic solvents include toluene, xylene, pseudocumene, dioxane, chloroform, methylene chloride,
Dichloroethane, ethanol, ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, chlorobenzene and the like can be mentioned.
These organic solvents are preferably selected appropriately depending on the type of aromatic polyester and imide compound. Although this extraction treatment using an organic solvent can be carried out at room temperature, it is preferable to carry out heating within a range that does not impair the morphology and physical properties of the polyester fiber, for example, under reflux conditions of the organic solvent. Further explanation will be given below with reference to Examples. Parts and % in Examples indicate parts by weight and % by weight, and the depth of color and friction discoloration resistance when dyeing the obtained polyester fibers were measured by the following method. (i) Depth of color Bathochromicity (K/S) is a measure of the depth of color.
was used. This value was determined by measuring the spectral reflectance (R) of the sample fabric using a Shimadzu RC-330 self-recording spectrophotometer.
Munk) formula. The larger this value is, the greater the deep color effect is. K/S=(1-R) ² /2R (measurement wavelength 500 mμ) In addition, K shows an absorption coefficient and S shows a scattering coefficient. (ii) Resistance to friction discoloration Using a Gakushin type flat abrasion machine for friction fastness testing, the test cloth was abraded a specified number of times under a load of 500 g using a dioset made of 100% polyethylene terephthalate as the friction cloth. hand,
The degree of discoloration was determined using a gray scale for discoloration. The case where the wear resistance was extremely low was rated as 1st grade, and the case where it was extremely high was rated as 5th grade. For practical purposes, level 4 or above is required. Examples 1 to 6 100 parts of polyethylene terephthalate chips having an intrinsic viscosity of 0.645 and a softening point of 260°C were dry-blended with a predetermined amount of the imide compound shown in Table 1, and then the resulting mixture was passed through a circular spinning hole with a pore diameter of 0.3 mm. Melt-spun at 275℃ using a spinneret with 24 holes,
Then, it was stretched at a stretching ratio of 4.5 times according to a conventional method to 75
A raw yarn of denier/24 filament was obtained. This raw yarn was strongly twisted with an S twist of 2500 T/m and a Z twist of 2500 T/m, and then the highly twisted yarn was steam-treated at 80° C. for 30 minutes to stop the twist. The twisted yarn has a warp density of 47 threads/cm and a weft density of 32.
A satin jersey fabric was woven by alternately arranging two S and Z twists at a thread/cm ratio. The obtained gray fabric was relaxed with a rotary washer for 20 minutes at boiling temperature, then grained, preset using a conventional method, and then treated with a 3.5% sodium hydroxide aqueous solution at boiling temperature to achieve a weight loss rate of 10. % fabric was obtained. The fabric after this alkali treatment is made into Dianix Black.
HG-FS (Mitsubishi Chemical Industries, Ltd. product) at 15% owf
After staining at 130℃ for 60 minutes, add 1g of sodium hydroxide/
A black-dyed cloth was obtained by reduction washing with an aqueous solution containing 1 g of hydrosulfite at 70° C. for 20 minutes.
Table 1 shows the color depth and friction discoloration resistance of this black cloth after 200 wears. FIG. 1 is an electron micrograph showing the surface of the constituent fibers of the black cloth obtained in Example 1, magnified 3500 times. Example 7 In place of the polyethylene terephthalate chips used in Example 1, 2.5 mol% of 5-Na sulfoisophthalic acid was copolymerized and the intrinsic viscosity was
The same procedure as in Example 1 was carried out except that 100 parts of copolymerized polyethylene terephthalate chips having a softening point of 258° C. and a softening point of 258° C. were used. The results are shown in Table 1. Example 8 In place of the polyethylene terephthalate chips used in Example 1, 100 parts of copolymerized polyethylene terephthalate chips with an intrinsic viscosity of 0.640 and a softening point of 259°C, which were copolymerized with 4% by weight of polyoxyethylene glycol having an average molecular weight of 600, were used. The same procedure as in Example 1 was carried out except that . The results are shown in Table 1. Example 9 The same procedure as in Example 1 was carried out, except that polytetramethylene terephthalate chips having an intrinsic viscosity of 0.88 were used in place of the polyethylene terephthalate chips used in Example 1, and the melt spinning temperature was 235°C. The results are shown in Table 1. Comparative Examples 1 to 4 Examples 1, 7, 8, and 9, respectively, except that the low molecular weight compounds used in Examples 1, 7, 8, and 9 were not used.
The same procedure as 8 and 9 was carried out. The results are shown in Table 1.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a photograph taken using an electron microscope and magnified 3500 times to show the surface of a polyester fiber according to the method of the present invention.

Claims (1)

[Claims] 1. The following conditions (1) are added to 100 parts by weight of aromatic polyester.
A polyester composition containing 0.1 to 30 parts by weight of an imide compound that satisfies (4) is melt-spun, and the resulting polyester fibers are treated with an aqueous solution of an alkaline compound to elute 2% by weight or more of the fibers. A method for producing porous polyester fiber, characterized by: (1) Substantially stable under the melting conditions of the aromatic polyester, non-reactive with the polyester, and compatible with the polyester. (2) Phase separation from the polyester does not occur when the polyester composition is cooled and solidified. (3) Melting point is 100℃ or higher. (4) Molecular weight is 1000 or less. 2 Aromatic polyester has the following general formula (m represents an integer of 2 to 6) The method for producing a polyester fiber according to claim 1, wherein the polyester fiber is mainly composed of repeating units represented by the following.