JP7235780B2 - Synthetic fiber treatment agent and method for producing synthetic fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a treatment agent for synthetic fibers and a method for producing synthetic fibers.

Conventionally, in the production of synthetic fibers by melt spinning organic polymers, in order to smoothly carry out the spinning operation and subsequent various processing steps such as drawing, winding, weaving, etc., so-called oil agents are used for the fibers. The application of treatment agents is widely practiced.

Various processing agents are used according to purposes in order to facilitate the spinning and drawing processes of fibers for industrial materials. In recent years, in order to improve productivity and quality, spinning and drawing speeds have been increasing, and heating elements such as drawing rollers have been increasing in temperature. Since the fiber is spun under such severe conditions, fluff and the like are likely to occur in the spinning and drawing steps. In particular, heat setting at high temperatures causes thermal decomposition, denaturation, and smoke generation of the oil, and equipment such as heating rollers is contaminated with denatured products, decomposed products, tar, etc., which causes thread breakage and fluffing. It's becoming

Therefore, there is known a technique for reducing smoking and fiber breakage by using a synthetic fiber treatment agent containing a polyhydric alcohol thioester compound (Patent Document 1).

JP-A-5-263361

However, under severe conditions such as those described above, the generation of smoke cannot be sufficiently reduced, and there is a problem of large friction occurring between the drawing roller and the fibers.
INDUSTRIAL APPLICABILITY The present invention provides a treatment agent for synthetic fibers that emits little smoke, is easy to remove tar because the tar accumulated on the drawing rollers is soft, and generates little friction between the drawing rollers and the fibers, and a method for producing synthetic fibers. The purpose is to

The present inventors have made intensive studies to solve the above problems, and as a result, have arrived at the present invention.
That is, the present invention provides a synthetic fiber treatment agent containing a compound (A) represented by the following general formula (1), wherein R ¹ and R Weight ratio of compound (A1) in which ² is a monoalcohol residue having 11 to 15 carbon atoms and compound (A2) in which each of R ¹ and R ² is a residue of a monoalcohol having 24 to 28 carbon atoms { (A1)/(A2)} is 0.001 to 0.1; and a method for producing the synthetic fiber.
R ¹ O—CO—(CH ₂ ) _m —S—(CH ₂ ) _n —CO—OR ² (1)
[In the general formula (1), R ¹ and R ² are each independently a residue obtained by removing a hydroxyl group from a monoalcohol (a) having 1 to 32 carbon atoms, and m and n are each independently 1 to 10 represents an integer of ]

When the synthetic fiber treatment agent of the present invention is used, less smoke is generated, the tar accumulated on the drawing rollers is soft, so that the tar can be easily removed, and the friction generated between the drawing rollers and the fibers is small.

The synthetic fiber treatment agent of the present invention contains a compound (A) represented by the following general formula (1).
R ¹ O—CO—(CH ₂ ) _m —S—(CH ₂ ) _n —CO—OR ² (1)
[In the general formula (1), R ¹ and R ² are each independently a residue obtained by removing a hydroxyl group from a monoalcohol (a) having 1 to 32 carbon atoms, and m and n are each independently 1 to 10 represents an integer of ]

In general formula (1), R ¹ and R ² are each independently a residue obtained by removing a hydroxyl group from monoalcohol (a) having 1 to 32 carbon atoms.
The monoalcohol (a) includes, for example, methanol, ethanol, linear or branched monoalcohols having 3 to 7 carbon atoms (propanol, butanol, etc.), saturated or unsaturated linear or branched monoalcohols having 8 to 32 carbon atoms, Mono alcohol {Natural alcohol such as octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, lauryl alcohol, tridecyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol and behenyl alcohol, Ziegler alcohol, oxo alcohol and secondary alcohol synthetic alcohol etc.} etc. are mentioned.

In the general formula (1), m and n are each independently an integer of 1 to 10, preferably 1 to 5, more preferably 2, from the viewpoint of reducing the friction generated between the drawing roller and the fiber. be.

In the present invention, the compound (A1) in which R ¹ and R ² in all the compounds (A) contained in the synthetic fiber treatment agent are residues of a monoalcohol having 11 to 15 carbon atoms, and R ¹ and R ² are The weight ratio {(A1)/(A2)} with the compound (A2), which is a residue of a monoalcohol having 24 to 28 carbon atoms, is 0.001 to 0.1, and 0.003 to 0.09. It is preferably from 0.005 to 0.08, more preferably from 0.005 to 0.08.
If the weight ratio {(A1)/(A2)} is less than 0.001, the friction generated between the drawing roller and the fibers increases, increasing the possibility of yarn breakage and fluffing. If it exceeds 0.1, the smoke emission becomes high, and the tar becomes hard and difficult to remove.

As the compound (A1) in the compound (A), one of alkyl alcohols having 11 to 15 carbon atoms (eg, dodecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecanol, 2-hexyl octanol, etc.) and sulfur-containing aliphatic dicarboxylic acids having 4 to 22 carbon atoms (e.g., thiodiacetic acid, 3,3'-thiodipropionic acid, 4,4'-thiodibutyric acid, 5,5'-thiodivaleric acid, 6,5'-thiodibutyric acid, 6'-thiodihexanoic acid, 8,8'-thiodioctanoic acid and 10,10'-thiodidecanic acid) and the like, specifically, diesters of dodecyl alcohol and thiodipropionic acid, lauryl alcohol and thiodipropionic acid diester, tridecyl alcohol and thiodipropionic acid diester, myristyl alcohol and thiodipropionic acid diester, pentadecanol and thiodipropionic acid diester, 2-hexyloctanol and thiodipropionic acid Examples include diesters with propionic acid and diesters with thiodipropionic acid and two alkyl alcohols among alkyl alcohols having 11 to 15 carbon atoms.

As the compound (A2) in the compound (A), alkyl alcohols having 24 to 28 carbon atoms (eg, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, 2-decyltetradecanol, 2-decyl hexadecanol, 2-decyloctadecanol, etc.) and a sulfur-containing aliphatic dicarboxylic acid having 4 to 22 carbon atoms (e.g., thiodiacetic acid, 3,3'-thiodipropionic acid, 4,4' -thiodibutyric acid, 5,5'-thiodivaleric acid, 6,6'-thiodihexanoic acid, 8,8'-thiodioctanoic acid and 10,10'-thiodidecanic acid, etc.). , tetracosanol and thiodipropionic acid diesters, pentacosanol and thiodipropionic acid diesters, hexacosanol and thiodipropionic acid diesters, heptacosanol and thiodipropionic acid diesters, octacosanol and thiodipropionic acid Examples include diesters with dipropionic acid, diesters with 2-decyltetradecanol and thiodipropionic acid, and diesters with two alkyl alcohols among alkyl alcohols having 24 to 28 carbon atoms and thiodipropionic acid. .

The content of compound (A) is preferably 10 to 60% by weight, more preferably 12 to 55% by weight, based on the weight of non-volatile components in the synthetic fiber treatment agent, from the viewpoint of smoke generation and tar hardness. %.
In the present invention, the non-volatile component is a residue after heating and drying 1 g of a sample in a glass dish in an uncovered glass petri dish at 130° C. for 45 minutes in a circulating air dryer.

From the viewpoint of compatibility of each component of the treatment agent, the treatment agent for synthetic fibers of the present invention preferably contains a compound (B) represented by the following general formula (2) in addition to the compound (A). .
R ³ O—(R ⁴ O) _p —CO—(CH ₂ ) _q —S—(CH ₂ ) _r —CO—(OR ⁵ ) _s —OR ⁶ (2)
[In the general formula (2), R ³ and R ⁶ are each independently a residue obtained by removing a hydroxyl group from a monoalcohol (a) having 1 to 32 carbon atoms, and R ⁴ and R ⁵ are each independently a carbon represents an alkylene group having a number of 2 to 4, p and s each independently represents an integer of 0 to 20, R ⁴ and R ⁵ when there are 2 or more may be the same or different, and the sum of p and s is It is an integer of 1-40, and q and r each independently represent an integer of 1-10. ]

In general formula (2), R ³ and R ⁶ are each independently a residue obtained by removing a hydroxyl group from monoalcohol (a) having 1 to 32 carbon atoms. Examples of the monoalcohol (a) include those similar to the monoalcohol (a) in the general formula (1).
The monoalcohol (a) is preferably a saturated or unsaturated linear or branched monoalcohol having 8 to 24 carbon atoms from the viewpoint of compatibility with each component of the treatment agent.

In general formula (2), R ⁴ and R ⁵ each independently represent an alkylene group having 2 to 4 carbon atoms, specifically an ethylene group, a 1,2-propylene group or a 1,3-propylene group, 1 , 2-, 1,3- or 1,4-butylene group, etc., and from the viewpoint of smoke generation, ethylene group and 1,2-propylene group are preferred, and ethylene group is more preferred.
R ⁴ O represents an alkyleneoxy group having 2 to 4 carbon atoms, specifically an ethyleneoxy group, 1,2- or 1,3-propyleneoxy group, 1,2-, 1,3- or 1, A 4-butyleneoxy group and the like can be mentioned, and from the viewpoint of smoke generation, an ethyleneoxy group and a 1,2-propyleneoxy group are preferred, and an ethyleneoxy group is more preferred.
OR ⁵ represents an oxyalkylene group having 2 to 4 carbon atoms, specifically an oxyethylene group, an oxypropylene group (-O-CH ₂ -CH ₂ -CH ₂ -, -O-CH(CH ₃ )- CH ₂ —, —O—CH ₂ —CH(CH ₃ )—, etc.), oxybutylene group (—O—CH ₂ —CH ₂ —CH 2 _{—CH 2} —, —O—CH(CH ₃ )—CH ₂ -CH ₂ -, -O-CH ₂ -CH(CH ₃ )-CH ₂ -, -O-CH ₂ -CH ₂ -CH(CH ₃ )-, etc.). An ethylene group and an oxypropylene group are preferred, and an oxyethylene group is more preferred.
p represents an integer of 0 to 20, preferably 1 to 10 from the viewpoint of smoke emission and appearance stability.
s represents an integer of 0 to 20, preferably 1 to 10 from the viewpoint of smoke generation and appearance stability.
The sum of p and s is 1 to 40, preferably 1 to 30, more preferably 1 to 20, from the viewpoint of compatibility of each component of the treatment agent.
When p and/or s is 2 or more, 2 or more R ⁴ and/or R ⁵ , R ⁴ O and/or OR ⁵ may be the same or different.

In general formula (2), q and r each independently represent an integer of 1 to 10, preferably 1 to 5, more preferably 2, from the viewpoint of appearance stability.

As the compound (B), other than the compound (A), an alkylene oxide (having 2 to 4 carbon atoms) of the monoalcohol (a) having 1 to 32 carbon atoms (for example, ethylene oxide (hereinafter abbreviated as EO)) , 1,2- or 1,3-propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3- or 1,4-butylene oxide (hereinafter abbreviated as BO), etc.) 1 to 20 mol addition and monoalcohol (a), and a sulfur-containing aliphatic dicarboxylic acid having 4 to 22 carbon atoms (e.g., thiodiacetic acid, 3,3'-thiodipropionic acid, 4,4' -thiodibutyric acid, 5,5'-thiodivaleric acid, 6,6'-thiodihexanoic acid, 8,8'-thiodioctanoic acid and 10,10'-thiodidecanic acid, etc.). , a diester of a lauryl alcohol EO 3 mol adduct and thiodipropionic acid, and a diester of a myristyl alcohol EO 3 mol adduct and thiodipropionic acid.

The content of the compound (B) is preferably 1 to 60% by weight, more preferably 5 to 60% by weight, based on the weight of the non-volatile components in the synthetic fiber treatment agent, from the viewpoint of compatibility of each component of the treatment agent. 50% by weight.

Compound (A) and compound (B) can be produced by various methods. For example, sulfur-containing aliphatic dicarboxylic acids having 4 to 22 carbon atoms {thiodiacetic acid, 3,3'-thiodipropionic acid, 4,4'-thiodibutyric acid, 5,5'-thiodivaleric acid, 6,6'- thiodihexanoic acid, 8,8′-thiodioctanoic acid and 10,10′-thiodidecanic acid} or a lower alkyl ester thereof with a monoalcohol (a) or an alkylene oxide (hereinafter abbreviated as AO) adduct of the monoalcohol (a) (the number of carbon atoms in the alkylene group is 2 to 4, and the number of added moles is 1 to 20).
As for the reaction conditions, a temperature of 165° C. to 170° C. and a degree of pressure reduction of 2.7 to 4 kPa are preferred because the acid values of the compounds (A) and (B) are low and the fumes are further reduced. In addition, by making the ratio (COOH/OH) of the carboxyl group in the sulfur-containing aliphatic dicarboxylic acid and the hydroxyl group in the monoalcohol (a) or the AO adduct of the monoalcohol (a) smaller than 1, the acid value is lowered. , is preferable because the smoke emission is lower.

The treatment agent for synthetic fibers of the present invention comprises a polyalkylene glycol fatty acid ester (C1), a polyhydric alcohol AO adduct fatty acid ester (C2), a monohydric alcohol AO adduct (C3), and an animal or vegetable oil having a hydroxyl group. It may contain at least one compound (C) selected from the group consisting of AO adducts (C4).
The compound (C) is used to make it easier to wash off the synthetic fiber treatment agent from the fiber after the fiber manufacturing process, and has the function of improving the emulsifiability of the synthetic fiber treatment agent.

As the polyalkylene glycol fatty acid ester (C1), a polyalkylene glycol having a weight average molecular weight (hereinafter abbreviated as Mw) measured by gel permeation chromatography (GPC) of 200 to 1,000 (as alkylene glycol Those having 2 to 3 carbon atoms, specifically polyethylene glycol, polypropylene glycol, etc.) and aliphatic carboxylic acids having 8 to 18 carbon atoms [aliphatic saturated carboxylic acids (caprylic acid, 2-ethylhexanoic acid, Pelargonic acid, capric acid, lauric acid, tridecanoic acid, isotridecanic acid, myristic acid, palmitic acid, stearic acid and isostearic acid, etc.) and animal and vegetable oil fatty acids (coconut oil fatty acid, palm oil fatty acid, hydrogenated castor oil fatty acid, hydrogenated beef tallow fatty acid, etc.) ) etc.].
Specifically, coconut oil fatty acid ester of polyethylene glycol (Mw: 200), lauric acid ester of polyethylene glycol (Mw: 400), capric acid ester of polyethylene glycol (Mw: 600), polyethylene glycol (Mw: 1000) 2-ethylhexanoic acid ester and coconut oil fatty acid ester of polypropylene glycol (Mw: 400).

The Mw of the polyalkylene glycol fatty acid ester (C1) can be measured using GPC under the following conditions.
<Mw measurement conditions>
Model: HLC-8120 [manufactured by Tosoh Corporation]
Column: TSK gel Super H4000
TSK gel Super H3000
TSK gel Super H2000
[All manufactured by Tosoh Corporation]
Column temperature: 40°C
Detector: RI
Solvent: Tetrahydrofuran Flow rate: 0.6 ml/min Sample concentration: 0.25% by weight
Injection volume: 10 μl
Standard: Polyoxyethylene glycol [manufactured by Tosoh Corporation; TSK STANDARDPOLYETHYLENE OXIDE] Data processing device: SC-8020 [manufactured by Tosoh Corporation]

Examples of the fatty acid ester (C2) of the polyhydric alcohol AO adduct include aliphatic polyhydric (di- to hexahydric) alcohols having 3 to 6 carbon atoms [aliphatic dihydric alcohols having 4 to 6 carbon atoms (1,4-butane diols, 1,6-hexanediol, neopentyl glycol, etc.), C 2-12 aliphatic tri- to hexahydric alcohols having 3-6 carbon atoms (glycerin, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, etc.)] AO (preferably the alkylene group has 2 to 4 carbon atoms) adduct, and aliphatic monocarboxylic acids having 8 to 24 carbon atoms [aliphatic saturated monocarboxylic acids (caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, lauric acid, tridecanoic acid, isotridecanic acid, myristic acid, oleic acid, palmitic acid, stearic acid and isostearic acid, etc.), animal and vegetable oil fatty acids (coconut oil fatty acid, palm oil fatty acid, hydrogenated castor oil fatty acid, hydrogenated beef tallow fatty acid, etc.) )] and the like.
The average added mole number of AO is preferably 1 to 80, more preferably 5 to 50, from the viewpoint of emulsifiability of the synthetic fiber treatment agent.
Specifically, 1,4-butanediol ethylene oxide (hereinafter abbreviated as EO) 20 mol adduct stearic acid mono or diester, neopentyl glycol EO 25 mol adduct hardened tallow fatty acid mono or diester, trimethylolpropane Lauric acid mono-, di- or triester of 24 mol EO adduct, mono-, di- or triester stearate of 24 mol EO trimethylolpropane adduct, coconut fatty acid mono-, di-, tri- or tetra-ester of 20 mol EO pentaerythritol adduct, Oleic acid mono-, di-, tri- or tetra-esters of sorbitan EO 20 mol adducts and palm oil fatty acid mono-, di-, tri- or tetra-esters of sorbitan EO 20 mol adducts are mentioned.
As (C2), fatty acid esters of trimethylolpropane-EO adducts and fatty acid esters of sorbitan-EO adducts are preferred from the viewpoint of emulsifiability of the synthetic fiber treatment agent.

The fatty acid ester (C2) of polyhydric alcohol AO adduct can be produced by various methods. For example, it can be produced by subjecting the polyhydric alcohol AO adduct and the fatty acid to an esterification reaction in the presence of a catalyst.
As the reaction conditions, a temperature of 165° C. to 170° C. and a degree of pressure reduction of 2.7 to 4 kPa are preferable because the acid value of (C2) is lowered and the fuming property is lowered. Further, it is preferable that the ratio of the carboxyl group in the fatty acid to the hydroxyl group in the polyhydric alcohol AO adduct (COOH/OH) is less than 1, because the acid value becomes lower and the smoke emission becomes lower.

Examples of the monohydric alcohol AO adduct (C3) include linear or branched alkyl monohydric alcohols having 4 to 26 carbon atoms (butanol, hexanol, octanol, 2-ethylhexanol, decanol, isodecanol, branched decanol, undecanol, isoundecanol, branched undecanol, dodecanol, isododecanol, branched dodecanol, tridecanol, isotridecanol, branched tridecanol, tetradecanol, branched tetradecanol, pentadecanol, hexadecanol, octadecanol, isooctane decanol, branched octadecanol, 2-octyldecanol, 2-decyldodecanol, 2-decyltetradecanol, 2-decylpentadecanol, 2-undecyltetradecanol and 2-undecylpentadecanol, etc. ) (wherein the alkylene group has 2 to 12 carbon atoms, preferably 2 to 4 carbon atoms in the alkylene group).
The number of moles of AO added is preferably 1 to 80, more preferably 5 to 50, from the viewpoint of emulsifiability of the synthetic fiber treatment agent.
Specifically, n-butanol EO 11 mol adduct, n-hexanol EO 9 mol adduct, n-octanol EO 11 mol adduct, 2-ethylhexanol EO 12 mol adduct, isodecyl alcohol EO 8 mol adduct , n-butanol EO 42 mol adduct, 2-ethylhexanol EO 40 mol adduct, isodecyl alcohol EO 38 mol adduct, dodecanol EO 12 mol adduct, branched dodecanol EO 5 mol adduct,
EO 13 mol adduct of tridecanol, branched tridecanol EO 5 mol adduct, tetradecanol EO 12 mol adduct, branched tetradecanol EO 5 mol adduct, octadecanol EO 13 mol adduct, branched octadecanol EO 12 mol Adducts, EO 15 mol adduct of 2-octyldecanol, EO 13 mol adduct of 2-decyltetradecanol, EO 13 mol adduct of 2-decylpentadecanol, EO 13 mol adduct of 2-undecyltetradecanol , EO 13 mol adduct of 2-undecylpentadecanol, n-butanol EO 11 mol/PO 8 mol random adduct, n-hexanol EO 9 mol/PO 7 mol random adduct, n-octanol EO 11 mol/PO 9 mol random adduct Adducts, EO 12 mol/BO 9 mol random adduct of 2-ethylhexanol, EO 8 mol/THF 6 mol random adduct of isodecyl alcohol, EO 42 mol/PO 32 mol random adduct of n-butanol, EO 40 mol of 2-ethylhexanol・PO 30 mol random adduct, isodecyl alcohol EO 38 mol/PO 28 mol random adduct, dodecanol EO 12 mol/PO 8 mol random adduct, tridecanol EO 13 mol/PO 7 mol random adduct, branched tridecanol EO 12 mol/PO 9 mol Random adduct, octadecanol EO 13 mol/PO 9 mol random adduct, branched octadecanol EO 12 mol/PO 7 mol random adduct, 2-octyldecanol EO 15 mol/PO 10 mol random adduct, 2-decyl tetra EO 13 mol/PO 9 mol random adduct of decanol, EO 13 mol/PO 9 mol random adduct of 2-decylpentadecanol, 2-undecyltetradecanol EO 13 mol/PO 9 mol random adduct, 2-undecyl penta 13 mol PO/9 mol EO random adduct of decanol, 17 mol PO/15 mol block adduct of n-butanol, 16 mol PO/14 mol EO adduct of n-hexanol, 15 mol PO/13 mol EO adduct of n-octanol , PO 15 mol/EO 13 mol block adduct of 2-ethylhexanol, PO 20 mol/EO 9 mol block adduct of 2-ethylhexanol, PO 15 mol/EO 12 mol block adduct of decyl alcohol, PO 18 mol/EO of isodecyl alcohol EO 7 mol block adduct, dodecanol EO 12 mol/PO 8 mol block adduct, tridecanol EO 13 mol/PO 7 mol block adduct, branched tridecanol EO 12 mol/PO 9 mol block adduct, octadecanol EO 13 mol/PO 9 mol block adduct Adducts, branched octadecanol EO 12 mol/PO 7 mol block adduct, 2-octyldecanol EO 15 mol/PO 10 mol block adduct, 2-decyltetradecanol EO 13 mol/PO 9 mol block adduct, 2- EO 13 mol/PO 9 mol block adduct of decylpentadecanol, EO 13 mol/PO 9 mol block adduct of 2-undecyltetradecanol, EO 13 mol/PO 9 mol block adduct of 2-undecylpentadecanol, and the like. be done.
(C3) is preferably a monohydric alcohol AO adduct having 6 to 20 carbon atoms from the viewpoint of emulsifiability of the synthetic fiber treatment agent, more preferably at least 1 mol or more of the AO to be added is EO. It is a monohydric alcohol AO adduct having 6 to 20 carbon atoms.

Examples of AO adducts (C4) of animal and vegetable oils having a hydroxyl group include AO of animal and vegetable oils having a hydroxyl group (hydrogenated castor oil, etc.) (the alkylene group has 2 to 12 carbon atoms, preferably an alkylene group. Examples thereof include adducts having 2 to 4 carbon atoms.
Specific examples include EO 10 mol adducts of hydrogenated castor oil and EO 25 mol adducts of hydrogenated castor oil.
(C4) is preferably an EO adduct of hydrogenated castor oil, more preferably an EO adduct of 10 to 50 mol of hydrogenated castor oil, from the viewpoint of emulsifiability of the synthetic fiber treatment agent.

As the emulsifier component (C), one type may be used, or two or more types may be used in combination. As the emulsifier component (C), a fatty acid ester (C5) of an AO adduct of an animal or vegetable oil having a hydroxyl group may be used. Examples of fatty acid esters (C5) of AO adducts of animal and vegetable oils having hydroxyl groups include esters (monoesters, diesters and triesters) of AO adducts of animal and vegetable oils having hydroxyl groups and aliphatic monocarboxylic acids. be done. Examples of AO adducts of animal and vegetable oils having hydroxyl groups include the same compounds as (C4) above. Examples of the aliphatic monocarboxylic acid include the aliphatic monocarboxylic acids having 8 to 24 carbon atoms exemplified in (C2) above. (C5) is preferably an oleic acid ester of an EO adduct of hydrogenated castor oil, more preferably a trioleate of an EO adduct of 10 to 50 moles of hydrogenated castor oil.
Of the emulsifier component (C), from the viewpoint of the emulsifiability of the treatment agent for synthetic fibers, the fatty acid ester (C2) of the polyhydric alcohol AO adduct, the monohydric alcohol AO adduct (C3), and the AO of animal and plant oils having hydroxyl groups are used. At least one selected from the group consisting of adducts (C4) is preferred, more preferably at least one selected from the group consisting of monohydric alcohol AO adducts (C3) and hydroxy-containing animal and vegetable oil AO adducts (C4) Seeds.

The content of the emulsifier component (C) is preferably 5 to 50% by weight, more preferably 5 to 50% by weight, based on the weight of the non-volatile component in the synthetic fiber treatment agent, from the viewpoint of improving the emulsifiability of the synthetic fiber treatment agent. is 18 to 48% by weight.

The treatment agent for synthetic fibers of the present invention may further contain an ester (D) of an aliphatic carboxylic acid and an aliphatic alcohol other than (A) and (C). When (D) is contained, smoothness can be imparted to the fibers, and friction generated between the drawing roller and the fibers during spinning can be further reduced.

Fatty acids constituting the ester (D) of an aliphatic carboxylic acid and an aliphatic alcohol include aliphatic monocarboxylic acids having 8 to 24 carbon atoms and aliphatic dicarboxylic acids having 4 to 24 carbon atoms.
Specific examples of aliphatic monocarboxylic acids having 8 to 24 carbon atoms include aliphatic saturated monocarboxylic acids having 8 to 24 carbon atoms (caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, lauric acid, tridecane acid, isotridecanic acid, myristic acid, palmitic acid, stearic acid and isostearic acid, etc.), aliphatic unsaturated monocarboxylic acids with 8 to 24 carbon atoms (oleic acid, elaidic acid, linoleic acid, linolenic acid, etc.), animal and vegetable oil fatty acids (Coconut oil fatty acid, palm oil fatty acid, castor oil fatty acid, hydrogenated castor oil fatty acid, beef tallow fatty acid, hydrogenated beef tallow fatty acid, lard fatty acid, etc.) and the like].
Examples of aliphatic dicarboxylic acids having 4 to 24 carbon atoms include saturated aliphatic dicarboxylic acids having 4 to 24 carbon atoms (such as succinic acid and adipic acid).

The following are examples of the aliphatic alcohol that constitutes the esterified product (D) of an aliphatic carboxylic acid and an aliphatic alcohol. For example, (x1) an aliphatic monohydric alcohol having 8 to 32 carbon atoms [aliphatic saturated monohydric alcohol (e.g., lauryl alcohol, palmityl alcohol, isostearyl alcohol, 2-decyltetradecanol, 2-octyldodecanol, etc.) ), aliphatic unsaturated monohydric alcohol (oleyl alcohol, etc.)]; (x2) aliphatic polyhydric (preferably dihydric to hexahydric) alcohol having 4 to 24 carbon atoms [aliphatic saturated dihydric alcohol (1,6- hexanediol and neopentyl glycol, etc.) and aliphatic saturated tri- to hexahydric alcohols (trimethylolpropane, pentaerythritol, sorbitol, etc.)] and the like.
From the viewpoint of smoothness, (D) is preferably an esterified product of an aliphatic carboxylic acid and an aliphatic mono- to tetrahydric alcohol, more preferably an esterified product of an aliphatic carboxylic acid and an aliphatic mono- to trihydric alcohol. is.

Esters (D) of aliphatic carboxylic acids and aliphatic alcohols can be produced by various methods. For example, it can be produced by subjecting the above-mentioned aliphatic alcohol {(x1) and/or (x2)} and the above-mentioned aliphatic carboxylic acid to an esterification reaction.
As the reaction conditions, a temperature of 165° C. to 170° C. and a degree of pressure reduction of 2.7 to 4 kPa are preferable because the acid value of (D) is lowered and the fumes are further lowered. Also, if the ratio of the carboxyl group in the aliphatic carboxylic acid to the hydroxyl group in the aliphatic alcohol (COOH/OH) is less than 1, the acid value is lowered and the fumes are further lowered, which is preferable.

The total content of the ester (D) of an aliphatic carboxylic acid and an aliphatic alcohol and the compound (A) is, based on the weight of the non-volatile component in the synthetic fiber treatment agent, 30 from the viewpoint of reducing friction. ~90% by weight is preferred, and 35 to 85% by weight is more preferred.

The synthetic fiber treatment agent of the present invention may further contain a silicone oil (E). When (E) is contained, the friction generated between the drawing roller and the fibers can be further reduced.
Examples of (E) include straight silicones in which the substituent is only a methyl group or a phenyl group, modified silicones in which other substituents are introduced, and the like. Specifically, polydimethylsiloxane, polymethyloctylsiloxane and alkyl-modified silicone and the like.

The content of the silicone oil (E) is 0.01 to 10% by weight, based on the weight of the non-volatile component in the synthetic fiber treatment agent, from the viewpoint of reducing the friction generated between the drawing roller and the fiber. is preferred, and more preferably 0.05 to 2% by weight.

The synthetic fiber treatment agent of the present invention may contain other known components (G) within limits that do not impair its performance.
(G) includes pH adjusters (metal alkalis such as sodium hydroxide and potassium hydroxide, organic amines such as alkylamines and AO adducts of alkylamines, organic acids such as oleic acid, etc.), antistatic agents (fatty acid soap, etc.), surface modifiers (dimethylpolysiloxane, alkyl-modified silicone, etc.), ultraviolet absorbers, antioxidants (hindered phenolic antioxidants such as Irganox 245 and Irganox 565, etc.), viscosity modifiers, and appearance A regulator and the like can be mentioned.
The total content of other known components (G) is preferably 10% by weight or less based on the weight of the synthetic fiber treatment agent.

The pH of a 1% by weight water-diluted solution of the treatment agent for synthetic fibers of the present invention is preferably 5 to 9, more preferably 6 to 8, from the viewpoint of preventing corrosion of spinning equipment and fiber processing equipment.
In addition, pH in this invention is the value measured at 25 degreeC based on JISZ8802.

The kinematic viscosity at 25° C. of the treatment agent for synthetic fibers of the present invention is preferably 20 to 500 mm ² /s, more preferably 40 to 400 mm ² /s, from the viewpoint of preventing yarn breakage and fluff.
The viscosity of the treatment agent for synthetic fibers is a value measured with an Ubbelohde viscometer.

There are no particular restrictions on the method for producing the synthetic fiber treatment agent of the present invention, and various methods can be used. For example, compound (A) and compound (B), optionally emulsifier component (C), ester of aliphatic carboxylic acid and aliphatic alcohol (D), silicone oil (E) and other known components (G) can be obtained by uniformly mixing at room temperature (eg, 25° C.) or by heating (eg, 30 to 90° C.) if necessary. There are no particular restrictions on the order and method of blending each component.

The synthetic fiber treatment agent of the present invention reduces smoke emission during spinning and drawing to improve the work environment, and the tar formed on the drawing roller is soft, so it is easy to remove the tar, and is generated between the drawing roller and the fiber. Since it can reduce friction, it can be used as a treatment agent for synthetic fibers used in industrial materials.

The synthetic fiber manufacturing method of the present invention is a manufacturing method including a step of attaching the synthetic fiber treatment agent of the present invention to the synthetic fiber in an amount of 0.1 to 3% by weight based on the weight of the synthetic fiber. .
As a method for attaching the treatment agent for synthetic fibers to the synthetic fibers, a known method or the like can be used, and the treatment agent can be applied before the spinning process, the drawing process, or the winding process using a roller or a guide lubricating device.
The adhesion rate of the synthetic fiber treatment agent of the present invention to synthetic fibers is preferably 0.5 to 1% by weight, based on the weight of the synthetic fibers before treatment, from the viewpoint of spinning properties and post-processing properties.

As a method for producing the synthetic fiber of the present invention, a mineral oil solution containing the synthetic fiber treatment agent of the present invention at a concentration of 15 to 90% by weight in mineral oil (F) is prepared, and the solution is applied to the synthetic fiber. As a treatment agent for synthetic fibers, it is preferably deposited in an amount of 0.1 to 3% by weight.

As the mineral oil (F), a mineral oil having a kinematic viscosity at 25°C of 10 to 3,000 mm ² /s (for example, a refined spindle oil having a kinematic viscosity at 25°C of 200 mm ² /s, a kinematic viscosity at 25°C of is 100 mm ² /s, etc.).
The content of the synthetic fiber treatment agent in the mineral oil solution is preferably 15 to 90% by weight, based on the weight of the mineral oil solution, from the viewpoint of operability during spinning.

The method for producing a synthetic fiber of the present invention can further include a step of hot drawing. The temperature for hot drawing is preferably 210 to 260° C. from the viewpoint of sufficiently transferring heat to the fiber and from the viewpoint of optimizing the yarn physical properties (strength, elongation, heat shrinkage, etc.).

In the present invention, synthetic fibers used in industrial materials are preferred as synthetic fibers, and more preferred are nylon fibers for air bags, fibers for seat belts and fibers for tire cords.

Synthetic fibers (industrial materials) treated with the synthetic fiber treatment agent of the present invention can be used for applications such as seat belts, tire cords and airbags.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. Below, parts mean parts by weight.

<Production Example 1: Production of (A1-1)>
89 g (0.5 mol) of thiodipropionic acid, 186 g (1.0 mol) of lauryl alcohol, and paratoluenesulfonic acid as an esterification catalyst were added to a 1-liter four-necked flask equipped with a stirrer and a thermocouple. 5 g and 0.4 g of a 50% by weight hypophosphorous acid aqueous solution as an anti-coloring agent were charged, and the temperature was gradually raised to 165° C. in a nitrogen atmosphere, and the esterification reaction was performed for 10 hours at a reduced pressure of 2.7 kPa. . After cooling to 95° C., 1.5 g of aluminum silicate (manufactured by Kyowa Chemical Industry Co., Ltd., “Kyoward 700SL”) was added and stirred for 30 minutes. Thereafter, diatomaceous earth was spread on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a diester of lauryl alcohol and thiodipropionic acid (A1-1). The acid value of (A1-1) was 1.5 mgKOH/g.

<Production Example 2: Production of (A1-2)>
A diester of myristyl alcohol and thiodipropionic acid (A1- 2) was obtained. The acid value of (A1-2) was 1.5 mgKOH/g.

<Production Example 3: Production of (A2-1)>
2-decyltetradecanol and thiodiene were prepared in the same manner as in Production Example 1, except that "186 g (1.0 mol) of lauryl alcohol" was replaced with "367 g (1.0 mol) of 2-decyltetradecanol". A diester (A2-1) with propionic acid was obtained. The acid value of (A2-1) was 1.5 mgKOH/g.

<Production Example 4: Production of (A2-2)>
Diester of octacosanol and thiodipropionic acid (A2-2) in the same manner as in Production Example 1 except that "186 g (1.0 mol) of lauryl alcohol" is replaced with "410 g (1.0 mol) of octacosanol" got The acid value of (A2-2) was 1.5 mgKOH/g.

<Production Example 5: Production of (B-1)>
In Production Example 1, 318 g (1.0 mol) of lauryl alcohol EO 3 mol adduct and thiodipropion were used in place of lauryl alcohol 186 g (1.0 mol). A diester (B-1) with an acid was obtained. The acid value of (B-1) was 1.5 mgKOH/g.

<Production Example 6: Production of (B-2)>
A diester (B-2) of a 3 mol adduct of myristyl alcohol EO and thiodipropionic acid was obtained in the same manner as in Production Example 5, except that 270 g of myristyl was used instead of 186 g of lauryl alcohol.

<Production Example 7: Production of (C2-1)>
183 g (0.64 mol) of stearic acid, 347 g (0.29 mol) of trimethylolpropane EO 24 mol adduct, paratoluene sulfone esterification catalyst were added to a 1 liter four-necked flask equipped with a stirrer and thermocouple. 0.5 g of acid and 0.4 g of 50% by weight hypophosphorous acid aqueous solution as an anti-coloring agent were added, and the temperature was gradually raised to 165° C. under a nitrogen atmosphere for 10 hours at a reduced pressure of 2.7 kPa to conduct an esterification reaction. did After cooling to 95° C., 1.5 g of magnesium silicate (manufactured by Kyowa Chemical Industry Co., Ltd., “Kyoward 600S”) was added and stirred for 30 minutes. Thereafter, diatomaceous earth was spread on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a diester (C2-1) of trimethylolpropane EO 24 mol adduct and stearic acid. The acid value of (C2-1) was 1.5 mgKOH/g.

<Production Example 8: Production of (C3-1)>
46 g (0.35 mol) of 2-ethylhexyl alcohol and 1.6 g of potassium hydroxide as a catalyst were charged into a dry AOA reactor, and after nitrogen substitution under reduced pressure, the temperature was raised to 100° C. and the degree of pressure reduction was 2.7 kPa. for 90 minutes. After dehydration, the temperature was raised to 160° C., and 284 g (4.9 mol) of propylene oxide was gradually added and the reaction was carried out at a pressure of 0.5 MPa (G). After aging until pressure equilibrium was reached, 194 g (4.4 mol) of ethylene oxide was gradually introduced and the reaction was carried out at a pressure of 0.5 MPa (G). 0.8 g of magnesium silicate (“Kyoward 600S” manufactured by Kyowa Chemical Industry Co., Ltd.) was added and stirred at 80° C. for 30 minutes. Thereafter, diatomaceous earth was spread on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a 2-ethylhexyl alcohol adduct (C3-1) of PO 14 mol EO 12.5 mol.

<Production Example 9: Production of (C4-1)>
280 g (0.3 mol) of hardened castor oil and 3.4 g of potassium hydroxide, which is a catalyst, were charged into a dried AOA reaction tank, and after nitrogen substitution under reduced pressure, the temperature was raised to 100 ° C. and the pressure was reduced to 90 at a pressure of 2.7 kPa. Dehydrated for 1 minute. After dehydration, the temperature was raised to 160° C., and 335 g (7.6 mol) of ethylene oxide was gradually added and the reaction was carried out at a pressure of 0.5 MPa (G). After aging until pressure equilibrium was reached, 1.6 g of magnesium silicate (“Kyoward 600S” manufactured by Kyowa Chemical Industry Co., Ltd.) was added and stirred at 80° C. for 30 minutes. Thereafter, diatomaceous earth was spread on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a hardened castor oil EO 25 mol adduct (C4-1).

<Production Example 10: Production of (C4-2)>
A hydrogenated castor oil EO 10 mol adduct (C4-2) was obtained in the same manner as in Production Example 6, except that 335 g (7.6 mol) of ethylene oxide was replaced with 132 g (3.0 mol) of ethylene oxide. rice field.

<Production Example 11: Production of (C5-1)>
254 g (0.9 mol) of oleic acid, 544 g (0.3 mol) of hydrogenated castor oil EO 20 mol adduct, para-toluene sulfone, an esterification catalyst, were added to a 1 liter four-necked flask equipped with a stirrer and thermocouple. 0.5 g of acid and 0.4 g of 50% by weight hypophosphorous acid aqueous solution as an anti-coloring agent were added, and the temperature was gradually raised to 165° C. under a nitrogen atmosphere for 10 hours at a reduced pressure of 2.7 kPa to conduct an esterification reaction. did After cooling to 95° C., 1.5 g of magnesium silicate (manufactured by Kyowa Chemical Industry Co., Ltd., “Kyoward 600S”) was added and stirred for 30 minutes. Thereafter, diatomaceous earth was laid on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a hydrogenated castor oil EO 20 mol adduct trioleate (C5-1).

<Production Example 12: Production of (D1-1)>
193 g (0.68 mol) of stearic acid, 220 g (0.74 mol) of 2-octyldodecanol, and p-toluenesulfonic acid as an esterification catalyst were placed in a 1-liter four-necked flask equipped with a stirrer and a thermocouple. 0.5 g and 0.4 g of a 50% by weight hypophosphorous acid aqueous solution as an anti-coloring agent were charged, the temperature was gradually raised to 165° C. under a nitrogen atmosphere, and the esterification reaction was performed for 10 hours at a reduced pressure of 2.7 kPa. rice field. After cooling to 95° C., 1.0 g of magnesium silicate (“Kyoward 600S” manufactured by Kyowa Chemical Industry Co., Ltd.) was added and stirred for 30 minutes. Thereafter, diatomaceous earth was spread on a filter paper (filter paper No. 1, manufactured by Advantech) to a thickness of 5 mm, and filtered to obtain a stearic acid ester of 2-octyldodecanol (D1-1). The acid value of (D1-1) was 1.5 mgKOH/g.

<Production Example 13: Production of (G2-1)>
A dry AOA reactor was charged with 81 g (0.3 mol) of beef tallow alkylamine and 3.4 g of potassium hydroxide as a catalyst. Dehydration was performed for 90 minutes. After dehydration, the temperature was raised to 160° C., and 198 g (4.5 mol) of ethylene oxide was gradually added and the reaction was carried out at a pressure of 0.5 MPa (G). Aging was carried out until pressure equilibrium was reached to obtain a beef tallow alkylamine EO 15 mol adduct (G2-1).

<Examples 1 to 8 and Comparative Examples 1 to 4>
Each component was blended in the blending weight parts shown in Table 1 to prepare synthetic fiber treatment agents of Examples 1 to 8 and Comparative Examples 1 to 4.

In addition, each component in Table 1 is as follows.
(A1-1): Diester of lauryl alcohol and thiodipropionic acid obtained in Production Example 1 (A1-2): Diester of myristyl alcohol and thiodipropionic acid obtained in Production Example 2 (A2-1): Diester (A2-2) of 2-decyltetradecanol and thiodipropionic acid obtained in Production Example 3: Diester (B-1) of octacosanol and thiodipropionic acid obtained in Production Example 4: Production Example 5 Diester (B-2) of the EO 3 mol adduct of lauryl alcohol obtained in Preparation Example 6 and thiodipropionic acid (C2-1): Diester of the 3 mol EO adduct of myristyl alcohol obtained in Production Example 6 and thiodipropionic acid Diester (C2-2) of trimethylolpropane EO 24 mol adduct obtained in Example 7 and stearic acid: sorbitan trioleate EO 20 mol adduct (manufactured by Sanyo Chemical Industries, Ltd., "Sandet OS-200A")
(C3-1): 2-ethylhexyl alcohol PO 14 mol EO 12.5 mol adduct obtained in Production Example 8 (C4-1): Hydrogenated castor oil EO 25 mol adduct obtained in Production Example 9 (C4-2): Production Hydrogenated castor oil EO 10 mol adduct obtained in Example 10 (C5-1): Hydrogenated castor oil EO 20 mol adduct trioleate obtained in Production Example 11 (D1-1): 2-octyldodecanol obtained in Production Example 12 Stearic acid ester (E1-1): dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd. "KF-96-20CS")
(E1-2): Alkyl aralkyl polyether-modified silicone ("DOW CORNING TORAY SF-8419 FLUID" manufactured by Dow Toray Industries, Inc.)
(G1-1): Irganox 245
(G2-1): Beef tallow alkylamine EO 15 mol adduct obtained in Production Example 13

Using the synthetic fiber treatment agents of Examples 1 to 9 and Comparative Examples 1 to 4 shown in Table 1, smoke generation properties, oil film strength, tar hardness and heating tension fluctuation of the synthetic fiber treatment agents were evaluated. Table 1 shows the results.

<Smoke emission evaluation method>
0.2 g of synthetic fiber treatment agent is weighed into an aluminum cap (diameter 40 mm, depth 7 mm), and heated at 250 ° C for 5 minutes with a dust tester manufactured by Shibata Science Co., Ltd. The amount of dust is measured by Shibata Science Co., Ltd. ) was recorded as the number of counts (CPM) with a digital dust meter AP-632T. It should be noted that the lower the value, the better the smoke emission. Moreover, if it is less than 15000 CPM, it is a level at which it can be judged that there is almost no smoke.

<Oil film strength evaluation method>
A test yarn in which the adjusted synthetic fiber treatment agent was attached to a commercially available nylon airbag yarn (470 dtx) so that the synthetic fiber treatment agent (pure content) was 1.0% by weight was subjected to a temperature of 250 ° C. The friction body (surface matte chrome plating, diameter 5 cm) is contacted with an initial load of 1000 g, a thread speed of 0.5 m / min, and a contact angle of 180 °, and the load (g) after contact is measured with a Toray high-load friction measuring instrument. bottom. A lower value means less friction and better oil film strength.

<Tar hardness evaluation method>
・Sample preparation 0.5 g of synthetic fiber treatment agent is weighed out in a SUS petri dish (50 mm in diameter, 10 mm in depth), and dried at 250 ° C. with an explosion-proof air circulation dryer SAFETY OVEN SPHH-101 manufactured by Espec Co., Ltd., damper 25. % for 24 hours.
・Hardness measurement The hardness of the heat-degraded synthetic fiber treatment agent is determined according to JIS K 5600-5-4: 1999 “General test method for paint-Part 5: Mechanical properties of coating film-Section 4: Scratch hardness (pencil method )” was measured by the handwriting method.
The hardness of the heat-degraded product of the prepared synthetic fiber treatment agent was measured. It should be noted that the lower the hardness, the better the removability of heat-degraded products of the treatment agent.

As is clear from Table 1, the synthetic fiber treatment agents of Comparative Examples 1 to 4, in which the weight ratio {(A1)/(A2)} is outside the range of the present invention, or contain only one of (A1) or (A2) has poor smoke emission and either tar hardness (Comparative Examples 1 and 4) or F/M friction tension (Comparative Examples 2 and 3), and is not satisfactory in high temperature processing of 250 ° C. I understand. On the other hand, when the synthetic fiber treatment agent of the present invention (Examples 1 to 9) is used, all of the smoke emission, tar hardness and F/M friction tension of the synthetic fiber treatment agent are improved in the treatment at a high temperature of 250 ° C. It turns out that it is a value which does not have any problem in evaluation. Therefore, the treatment agent for synthetic fibers of the present invention produces little smoke even when treated at high temperatures, and the tar that accumulates on the drawing rollers is soft, making it easy to remove the tar. It can be seen that it is a treatment agent for synthetic fibers with a small .

The treatment agent for synthetic fibers of the present invention emits little smoke, the tar accumulated on the drawing roller is soft, so it is easy to remove the tar, and the friction generated between the drawing roller and the fiber is small. Even if the stretching speed is increased and the temperature of the heated body such as the stretching roller is increased, the removal of heat-degraded substances from the treatment agent is excellent. , and can be suitably used in the spinning and drawing processes of nylon fibers for straight oil-feeding airbags.

Claims (5)

A synthetic fiber treatment agent containing a compound (A) represented by the following general formula (1), wherein R ¹ and R ² in all compounds (A) contained in the synthetic fiber treatment agent each have a carbon number The weight ratio of the compound (A1) which is a residue of a monoalcohol having 11 to 15 carbon atoms and the compound (A2) which is a residue of a monoalcohol having 24 to 28 carbon atoms in each of R ¹ and R ² {(A1)/( A2)} is 0.001 to 0.1,
Based on the weight of the synthetic fiber treatment agent, the content of the compound (A1) is 0.1 wt% to 5.4 wt%, and the content of the compound (A2) is 9.9 wt% to 59 wt%. 0% by weight synthetic fiber treatment agent.
R ¹ O—CO—(CH ₂ ) _m —S—(CH ₂ ) _n —CO—OR ² (1)
[In the general formula (1), R ¹ and R ² are each independently a residue obtained by removing a hydroxyl group from a monoalcohol (a) having 1 to 32 carbon atoms, and m and n are each independently 1 to 10 represents an integer of ] The treatment agent for synthetic fibers according to claim 1, further comprising a compound (B) represented by the following general formula (2).
R ³ O—(R ⁴ O) _p —CO—(CH ₂ ) _q —S—(CH ₂ ) _r —CO—(OR ⁵ ) _s —OR ⁶ (2)
[In the general formula (2), R ³ and R ⁶ are each independently a residue obtained by removing a hydroxyl group from a monoalcohol (a) having 1 to 32 carbon atoms, and R ⁴ and R ⁵ are each independently a carbon represents an alkylene group having a number of 2 to 4, p and s each independently represents an integer of 0 to 20, R ⁴ and R ⁵ when there are 2 or more may be the same or different, and the sum of p and s is It is an integer of 1-40, and q and r each independently represent an integer of 1-10. ] Fatty acid ester of polyalkylene glycol (C1), fatty acid ester of polyhydric alcohol alkylene oxide adduct (C2), monohydric alcohol alkylene oxide adduct (C3) and alkylene oxide adduct of animal and vegetable oil having hydroxyl group (C4) The treatment agent for synthetic fibers according to claim 1 or 2, containing at least one compound (C) selected from the group consisting of: The synthetic fiber treatment agent according to any one of claims 1 to 3, wherein the content of the compound (A) is 10 to 60% by weight based on the weight of nonvolatile components in the synthetic fiber treatment agent. . A method for producing synthetic fibers, comprising the step of applying the synthetic fiber treatment agent according to any one of claims 1 to 4 in an amount of 0.1 to 3% by weight based on the weight of the synthetic fibers.