JP6767574B2 - Color inhibitor for polyurethane, its manufacturing method, and polyurethane molded product - Google Patents

Description

The present invention relates to a color inhibitor for polyurethane, a method for producing the same, and a polyurethane molded product. More specifically, the present invention relates to a color inhibitor for polyurethane that can be used for polyurethane molded products such as polyurethane elastic fibers and polyurethane films.
This application claims priority based on Japanese Patent Application No. 2017-090558 filed in Japan on April 28, 2017, the contents of which are incorporated herein by reference.

The surface of polyurethane molded bodies such as polyurethane elastic fibers and polyurethane films is easily discolored or deteriorated by exhaust gas, heat, ultraviolet rays, chlorine bleach, chlorine sterilizing agents for pool sterilization, and the like.

For example, when dyeing a fabric using polyurethane elastic fibers, in order to improve the finish of the fabric by smoothing the dyeing and finishing work in the previous step, the fabric before dyeing and finishing (living machine (Kibata)) A smelting process is required to remove dirt such as textile oils adhering to the fabric and machine oil scattered from the knitting and weaving machines. If the refining process is inadequate, there is a risk that the oil-adhered portion will not be partially dyed when the fabric is dyed, resulting in a defect called whitening, which will greatly reduce the commercial value.

In the refining process, warm water containing a surfactant is usually used, but since fiber oils and machine oils are poorly water-soluble, it may be difficult to sufficiently remove them with normal water containing a surfactant. .. Therefore, when the degree of pollution is severe, a method of performing a refining step using an organic solvent such as perchlorethylene that dissolves these oils well is used. In addition, outerwear and jeans made of polyurethane elastic fibers, and rain gear and outdoor clothing made of polyurethane breathable waterproof film are used by consumers to remove edible oils, lipsticks, and sebum stains that occur in their daily lives when they wear clothes. When removing stains that are difficult to remove with household detergent alone, the stains may be sent for dry cleaning. The same clothing may be dry-cleaned and washed several times a year.

Organic solvents such as perchlorethylene used in the refining process and dry cleaning washing have extremely strong dissolving power, so not only pollutants but also stabilizers that are added in advance to polyurethane fibers for the purpose of improving durability, etc. Also elutes from the fibers and films, which may significantly reduce the consumption durability of clothing products.

The cause of the discoloration of the polyurethane elastic fiber is that the surface of the elastic fiber is discolored or deteriorated due to the attack on the thread surface of the polyurethane elastic fiber by NOx gas or ultraviolet rays existing in the atmosphere. Therefore, it is more effective that the color-preventing stabilizer is thickly distributed and present in the vicinity of the surface portion than in the central portion of the fiber or film.
For this reason, a color inhibitor for polyurethane having a relatively low molecular weight tertiary nitrogen group in which the color inhibitor added to the polyurethane polymer easily migrates from the inside of the fiber or film to the surface in a short period of time has been proposed. (Patent Documents 1 to 3).

However, the fibers and films wound around the paper tube are subject to friction as they pass through rollers, reeds, beam surfaces, knitting needles and guides in the process of being processed into fabric. At that time, if the anti-coloring agent is thickly present on the surface, it is scraped off from the surface by friction, and scum (thread residue) accumulates on the rollers, reeds, and knitting needles. In the case of polyurethane elastic fiber, this becomes resistance, tension unevenness of the fiber occurs, the surface of the knitted fabric becomes uneven, the quality of the fabric deteriorates, the commercial value of the fabric deteriorates, and the yarn is sharpened during knitting. It may cause troubles such as causing it.
Further, even in dry cleaning washing and repeated washing, if the coloring inhibitor has a relatively low molecular weight, the coloring inhibitor tends to fall off from the surface, and the coloring resistance performance deteriorates every time washing or dry cleaning is repeated. ..

On the other hand, when a color inhibitor composed of a relatively high molecular weight compound having a semicarbazide group at the end is used, the color inhibitor may be removed from the surface by a refining step, dry cleaning washing, repeated washing, or the like. It can be suppressed and its shortcomings can be compensated (Patent Document 4).

Special Fair 6-78483 Gazette Tokuhei 4-55223 Gazette Special Fair 5-68490 Gazette Special Fair 2-34985 Gazette

However, when the polyurethane composition disclosed in Patent Document 4 is used, the transfer speed from the urethane polymer to the surface is slow due to the high molecular weight, so that the immediate effect after spinning is poor, for example, before shipment. Unprocessed films and fibers wrapped around paper tubes during storage in the warehouse and undyed fabrics may be colored if exposed to the relatively high concentration of exhaust gas from the transport vehicles in the warehouse.

Further, in the compound having a terminal semicarbazide group, the stabilizer is easily removed by repeated washing, the stabilizing performance is not sufficient, and the fibers are discolored or brittle due to the chlorine bleach used in washing. There is a problem.
Furthermore, the dialkylhydrazine used in synthesizing compounds having a terminal semicarbazide group is expensive.

Furthermore, in the production process of the maleimide structure compound, the reaction of diamine on the maleic anhydride skeleton is often complicated and the reaction is incomplete, so that minute gels are likely to be generated. In that case, there is a problem that the filter is clogged in the spinning process or the yarn breaks in the spinning process.

The present invention has been made in view of the above circumstances, and is for polyurethane which has an immediate effect of preventing coloration and has a long-lasting effect of preventing coloration even after repeated washing and dry cleaning washing. It provides an anti-coloring agent, a method for producing the same, and a polyurethane molded product.

The present inventors have diligently studied a color-preventing agent capable of sufficiently exerting the color-preventing effect of a thin and thin polyurethane molded product such as a fiber or a film. As a result, by using a polyurethane compound having three characteristics of a specific chemical structure, a specific number average molecular weight, and a specific wide molecular weight distribution at the same time, it is possible to adjust the transfer rate of the anticoloring agent from the inside to the surface of the polyurethane molded product. , And completed the color inhibitor for polyurethane of the present invention.
That is, the present invention includes the following aspects.
[1] A coloring inhibitor for polyurethane composed of a polymer composition having a structural unit represented by the following general formula (3), wherein the number average molecular weight (Mn) of the polymer composition is 10,000 ≦ Mn ≦ 80,000. A color inhibitor for polyurethane, which has a molecular weight distribution degree (Mw / Mn) calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw) of 1.30 or more and 2.55 or less.
-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

[2] The organic diisocyanate (B) is a linear aliphatic diisocyanate, a branched chain aliphatic diisocyanate, a cyclic aliphatic diisocyanate, an aliphatic diisocyanate having an aromatic ring, or an aromatic. The anticoloring agent for polyurethane according to the above [1], which is a group diisocyanate.

[3] The color inhibitor for polyurethane according to the above [1] or [2], wherein R ³ in the general formula (3) is an alkyl group having 3 to 7 carbon atoms.

[4] The color inhibitor for polyurethane according to any one of the above [1] to [3], wherein i in the general formula (3) is 1 and j is 1.

[5] A polyurethane compound (C1) having a structural unit represented by the following general formula (3) and a number average molecular weight of the polyurethane compound (C1) having a structural unit represented by the following general formula (3). A method for producing a color inhibitor for polyurethane, which is mixed with a polyurethane compound (C2) having a number average molecular weight (Mn) smaller than (Mn).

-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

[6] A polyurethane molded product containing the polyurethane coloring inhibitor according to any one of the above [1] to [4] and a polyurethane polymer.

[7] The polyurethane molded product according to the above [6], wherein the polyurethane molded product is a polyurethane elastic fiber or a polyurethane film.
[8] The use of a polymer composition having a structural unit represented by the following general formula (3) as a color inhibitor in the production of a polyurethane molded product.
The number average molecular weight (Mn) of the polymer composition is 10,000 ≦ Mn ≦ 80,000, and the molecular weight distribution degree (Mw / Mn) calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw) is Use as a color inhibitor, 1.30 or more and 2.55 or less.
-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). It is a group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

The color-preventing agent for polyurethane of the present invention has an immediate effect of color-prevention, and the color-preventing effect is long-lasting even after repeated washing and dry-cleaning washing.

[Anticoloring agent for polyurethane]
The color inhibitor for polyurethane of the present invention comprises a polymer composition having a structural unit represented by the following general formula (3), and the number average molecular weight (Mn) of the polymer composition is 10,000 ≦ Mn ≦ 80,000. Moreover, the molecular weight distribution degree (Mw / Mn) calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw) is 1.30 or more and 2.55 or less.

-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

As represented by the general formula (3), the polymer constituting the color inhibitor for polyurethane of the present invention has a tertiary nitrogen group in the repeating constituent unit, and therefore has an excellent color preventing effect. Further, since the polymer is a linear polyurethane compound, it has good affinity with the polyurethane polymer when mixed with the polyurethane polymer for a polyurethane molded product.

The number average molecular weight (Mn) of the polymer composition is 10,000 ≦ Mn ≦ 80,000, preferably 15,000 ≦ Mn ≦ 70,000, and more preferably 18,000 ≦ Mn ≦ 60,000. When the number average molecular weight (Mn) of the polymer composition is less than 10,000, the color inhibitor for polyurethane is likely to come off during dry cleaning of the polyurethane elastic fiber using the color inhibitor composed of the polymer composition, and the color inhibitor for polyurethane is more than 80,000. If it is large, it becomes difficult for the color-preventing agent to migrate from the molded body to the surface of the molded body, and the anti-coloring effect is reduced.

The lower limit of the molecular weight distribution (Mw / Mn) of the polymer composition is 1.30 or more, preferably 1.32 or more, more preferably 1.35 or more, and 1.40 or more. It may be 1.45 or more, and the upper limit value is 2.55 or less, preferably 2.20 or less, and more preferably 2.00 or less, 1,90. It may be less than or equal to 1,80 or less, and may be 1,70 or less.

Since the polymer composition has a specific number average molecular weight (Mn) and a relatively large molecular weight distribution (Mw / Mn), it is compared with a polymer component having a relatively small molecular weight in the polymer composition. A polymer component having a large molecular weight coexists. When the polymer composition is used as a color inhibitor for polyurethane, the polymer component having a relatively small molecular weight in the polymer composition rapidly precipitates on the surface from the object, resulting in immediate coloring. It can have a preventive effect. Further, the polymer component having a relatively large molecular weight in the polymer composition has extraction resistance to an organic solvent, stays in the object, and gently migrates to the surface of polyurethane. Therefore, the color-preventing agent for polyurethane made of the polymer composition can maintain the color-preventing effect for a long period of time even after repeated washing and dry-cleaning washing.

When the molecular weight distribution (Mw / Mn) of the polymer composition is less than 1.30, the anti-coloring effect becomes insufficient, and when the molecular weight distribution (Mw / Mn) is larger than 2.55, coloring is performed. Since the transfer speed of the inhibitor from the molded body to the surface of the molded body varies, the anticoloring effect becomes insufficient. In this case, it is possible to make up for this defect by increasing the amount added, but not only is it not economical, but the elastic recovery property of the polyurethane elastic fiber at the time of elongation, which is a characteristic, is lowered.

The polymer constituting the color inhibitor for polyurethane of the present invention is represented by the following general formula (1) obtained by reacting an alkylamine having 1 to 10 carbon atoms or a derivative thereof with an alkylene oxide having 2 to 5 carbon atoms. It is obtained by reacting the tertiary nitrogen-containing diol (A) to be produced with the organic diisocyanate (B) represented by the following general formula (2).

H- (OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- H ... (1)
OCNR ⁴ NCO ・ ・ ・ (2)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B) . The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

In the polymer composition constituting the color inhibitor for polyurethane of the present invention, it is preferable that the polymer in which i and j in the general formula (1) are 1 is the main component. Since the alkylene oxide is reacted, a polymer in which i and / or j is 2 may be contained, a polymer in which i and / or j is 3 may be contained, and i and / or j may be contained. A polymer having j of 4 may be contained. "The polymer is the main component" means that 50% by mass or more of the composition is the polymer.

In the tertiary nitrogen-containing diol (A), R ¹ and R ² are alkylene groups having 2 to 5 carbon atoms, and R ³ is an alkyl group having 1 to 10 carbon atoms. If the number of carbon atoms is larger than these, a sufficient anti-coloring effect cannot be obtained.

In the tertiary nitrogen-containing diol (A), R ³ may be an alkyl group having 3 to 10 carbon atoms, an alkyl group having 3 to 7 carbon atoms, or an alkyl group having 4 to 10 carbon atoms. It may be an alkyl group or an alkyl group having 4 to 7 carbon atoms.

Preferred tertiary nitrogen-containing diols (A) are N-butyl-bis (2-hydroxyethyl) amines (ie, Nn-butyl-N, N-diethanolamine), N-t-. Pentyl-bis (2-hydroxypropyl) amine, N-butyl-bis (2-hydroxypropyl) amine, N-butyl-bis (2-hydroxybutyl) amine, N, N-bis (2-hydroxyethyl) -isobutyl Amine, N, N-bis (2-hydroxypropyl) -isobutylamine, N, N-bis (2-hydroxybutyl) -isobutylamine, N, N-bis (2-hydroxyethyl) -t-butylamine, N, N-bis (2-hydroxypropyl) -t-butylamine, N, N-bis (2-hydroxybutyl) -t-butylamine, N, N-bis (2-hydroxyethyl) -1,1-dimethylpropylamine, N, N-bis (2-hydroxypropyl) -1,1-dimethylpropylamine (ie, N-t-pentyl-N, N-dipropanolamine), N, N-bis (2-hydroxybutyl) )-1,1-Dimethylpropylamine and the like. These may be used alone or in admixture of a plurality of types.

The organic diisocyanate (B) may be a linear aliphatic diisocyanate, a branched chain aliphatic diisocyanate, or a cyclic aliphatic diisocyanate. It may be an aliphatic diisocyanate having an aromatic ring, or it may be an aromatic diisocyanate.

Preferred examples of the linear aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and the like, and preferred branched chain aliphatic diisocyanate. As a cyclic aliphatic diisocyanate, preferably, 3-methylhexane-1,6-diisocyanate, 3-3'-dimethylpentane-1,5-diisocyanate and the like can be mentioned, and preferably 1 , 3-Cyclohexylene-diisocyanate, 1,4-cyclohexylene-diisocyanate, isophorone diisocyanate, 4-4'-methylenedicyclohexyl-diisocyanate, etc., and aliphatic diisocyanate having an aromatic ring. As the nart, preferably, m-xylylene diisocyanate, p-xylylene diisocyanate, α, α, α', α'-tetramethyl-p-xylylene diisocyanate and the like can be mentioned, and as aromatic diisocyanate. , Preferably 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, trilen-2,6-diisocyanate, trilen-2,4- Examples include diisocyanate. These may be used alone or in admixture of a plurality of types.

The organic diisocyanate (B) is preferably a linear aliphatic diisocyanate, a branched chain aliphatic diisocyanate, or a cyclic aliphatic diisocyanate from the viewpoint of anticoloring performance.

[Manufacturing method of color inhibitor for polyurethane]
The color inhibitor for polyurethane and the polymer composition have a polyurethane compound (C1) having a structural unit represented by the following general formula (3) and a structural unit represented by the following general formula (3). It can be produced by mixing a polyurethane compound (C2) having a number average molecular weight (Mn) smaller than the number average molecular weight (Mn) of the polyurethane compound (C1).
More specifically, the color inhibitor for polyurethane and the polymer composition are a tertiary nitrogen-containing diol (A) represented by the following general formula (1) and an organic diisosia represented by the following general formula (2). Polyurethane compound (C1) having a structural unit represented by the following general formula (3) is synthesized by polymerizing with nat (B), and also contains tertiary nitrogen represented by the following general formula (1). The polyurethane compound (C1) has a structural unit represented by the following general formula (3) by polymerizing the diol (A) and the organic diisocyanate (B) represented by the following general formula (2). It can be produced by synthesizing a polyurethane compound (C2) having a number average molecular weight (Mn) smaller than the number average molecular weight (Mn) of the above, and mixing the polyurethane compound (C1) with the polyurethane compound (C2). it can.

H- (OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- H ... (1)
OCNR ⁴ NCO ・ ・ ・ (2)
-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.)

When synthesizing the polyurethane compound (C1), the charged molar ratio ((A) / (B)) of the tertiary nitrogen-containing diol (A) and the organic diisocyanate (B) is 1.00 to 1 It may be .100, 1.002 to 1.080, 1.004 to 1.060, 1.006 to 1.040, and 1.008. It may be ~ 1.020. The closer the charged molar ratio ((A) / (B)) is to 1.000, the easier it is to synthesize the high molecular weight polyurethane compound (C1).

The number average molecular weight (Mn) of the polyurethane compound (C1) may be 30,000 ≦ Mn ≦ 200,000, 40,000 ≦ Mn ≦ 150,000, or 50,000 ≦ Mn ≦ 100,000.

The molecular weight distribution (Mw / Mn) of the polyurethane compound (C1) may be 1.00 or more and 1.45 or less, 1.080 or more and 1.40 or less, and 1.16 or more and 1 It may be .35 or less, and may be 1.24 or more and 1.30 or less.

The molar ratio ((A) / (B)) of the tertiary nitrogen-containing diol (A) and the organic diisocyanate (B) when synthesizing the polyurethane compound (C2) is 1.104 to 1. It may be .250, 1.108 to 1.240, 1.112 to 1.230, 1.116 to 1.220, 1.120. It may be ~ 1.210. The larger the charged molar ratio ((A) / (B)) is larger than 1.000, the lower the molecular weight of the polyurethane compound (C2).

The number average molecular weight (Mn) of the polyurethane compound (C2) may be 4000 ≦ Mn ≦ 40,000, 6000 ≦ Mn ≦ 30,000, or 8000 ≦ Mn ≦ 20,000.

The molecular weight distribution (Mw / Mn) of the polyurethane compound (C2) may be 1.00 or more and 1.45 or less, 1.080 or more and 1.40 or less, and 1.16 or more and 1 It may be .35 or less, and may be 1.24 or more and 1.30 or less.

The number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) of the polyurethane compound (C1) and the polyurethane compound (C2) are measured in advance, and the desired number average is adjusted by appropriately adjusting the mixing ratio. The molecular weight (Mn) and the molecular weight distribution (Mw / Mn) can be set. Then, by mixing two or more kinds of polyurethane compounds having a tertiary nitrogen group with different number average molecular weights and giving them a wide molecular weight distribution, there is an immediate effect of color prevention and color prevention for a long period of time. It is possible to obtain an antioxidant for polyurethane having a long-lasting effect.

The color inhibitor for polyurethane, which has a structural unit represented by the general formula (3) and is composed of a polymer composition having a large molecular weight distribution (Mw / Mn), is a number average molecular weight (Mn) of the polyurethane compound (C1). ) Is adjusted to be relatively large as described above, the number average molecular weight (Mn) of the polyurethane compound (C2) is adjusted to be relatively small as described above, and each is produced in different production batches and then mixed. Can be easily manufactured with.
The synthesis of the polyurethane compound (C1) and the synthesis of the polyurethane compound (C2) may be carried out first. That is, the polyurethane compound (C2) may be synthesized after the polyurethane compound (C1) is synthesized, or the polyurethane compound (C1) may be synthesized after the polyurethane compound (C2) is synthesized.

[Polyurethane molded product]
The polyurethane molded product of the present invention contains the above-mentioned color inhibitor for polyurethane and a polyurethane polymer.

As represented by the general formula (3), the polymer constituting the color inhibitor for polyurethane is a linear polyurethane compound having tertiary nitrogen in the repeating constituent unit, and is therefore mixed with the polyurethane polymer. In addition, the affinity with the polyurethane polymer is also good. Further, since the process for producing the polymer constituting the color inhibitor for polyurethane is simple and easy to produce, and the generation of gelled substances is small, when the color inhibitor for polyurethane and the polyurethane polymer are mixed. Difficult to separate phases.

In the polyurethane molded product, the content ratio of the solid content of the color inhibitor for polyurethane to 100 parts by mass of the polyurethane polymer may be 0.01 parts by mass or more as a lower limit value, and 0.05 parts by mass. It may be 0 parts by mass or more, 0.20 parts by mass or more, and the upper limit value may be 10 parts by mass or less, or 8 parts by mass or less. It may be 1 part by mass or less, or 0.5 part by mass or less. The effect is exhibited by containing an amount of the lower limit value or more and the upper limit value or less.

In the present specification, the polyurethane polymer may be a polyurethane urea polymer used for a general polyurethane molded body such as a polyurethane elastic fiber or a polyurethane film, or may be a polymer composed only of polyurethane. However, polymers having a structural unit represented by the general formula (3) are excluded.

As for the method for producing a polyurethane polymer, known polyurethane-forming reaction techniques such as a prepolymer method and a one-shot method can be used. For example, a high molecular weight polyol and diisocyanate are reacted under the condition of excess diisocyanate to synthesize a urethane prepolymer having an isocyanate group at the terminal, and then this urethane prepolymer is subjected to a chain extension reaction with a low molecular weight diol. This can be done to obtain a polyurethane compound.

The polyurethane urea polymer can be obtained by reacting, for example, a polymer polyol, a diisocyanate, a diamine, and a terminal terminator having a monofunctional active hydrogen atom.

Examples of the diisocyanate used for producing the polyurethane polymer include aromatic diisocyanate compounds, and may be an aliphatic or alicyclic diisocyanate compound.

In the polyurethane molded product of the present invention, the polymer having the structural unit represented by the general formula (3) in the color inhibitor for polyurethane and the type of diisocyanate used in the production of each of the polyurethane polymers are the same. It may be very different, and the diisocyanate exemplified as the organic diisocyanate (B) can be used.

The diisocyanate used in the production of the polyurethane polymer may be a linear aliphatic diisocyanate, a branched chain aliphatic diisocyanate, or a cyclic aliphatic diisocyanate from the viewpoint of anticoloring performance. From the viewpoint of heat resistance of polyurethane molded products such as polyurethane elastic fibers and polyurethane films, aromatic diisocyanates are preferable.

As the polyurethane polymer used here, for example, a known technique is used in which a polymer glycol and a diisocyanate compound are reacted to synthesize a urethane intermediate polymer to be a soft segment, and then a hard segment is polymerized with a chain extender. be able to. When a diol compound is used as the chain extender, a polyurethane polymer having a hard segment having a urethane bond can be obtained, and when a diamine compound is used, a polyurethane urea polymer having a hard segment having a urea bond can be obtained.

Examples of the polymer glycol include polyether diols such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, and polyoxypentamethylene glycol, or adipic acid, sebatic acid, maleic acid, itaconic acid, and azelaic acid. , One or more dibasic acids such as malonic acid and ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,4-butane Obtained from one or more glycols such as diols, 1,3-butanediol, hexamethylene glycol, diethylene glycol, 1,10-decanediol, 1,3-dimethylolcyclohexane, 1,4-dimethylolcyclohexane and the like. Polylactone diol, or polyesteramide diol, polyester ether diol, polylactone diol such as poly-ε-caprolactone diol, polyvalerolactone diol, polycarbonate diol, polyacrylic diol, polythioether diol, polythioesterdiol, or these diols. Examples thereof include copolymers and mixtures thereof, and these may be used alone or in admixture of a plurality of types.

Examples of the isocyanate compound include methylene-bis (4-phenylisocyanate), methylene-bis (3-methyl-4-phenylisocyanate), 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate. Nate, m-xylylene diisocyanate, p-xylylene diisocyanate, α, α, α', α'-tetramethyl-xylylene diisocyanate, m-phenylenedi isocyanate, p-phenylenedi isocyanate, 4 , 4'-dimethyl-1,3-xylylene diisocyanate, 1-alkylphenylene-2,4-diisocyanate, 1-alkylphenylene-2,6-diisocyanate, 3- (α-isocyanate ethyl) Phenylisocyanate, 2,6-diethylphenylene-1,4-diisocyanate, diphenyl-dimethylmethane-4,4-diisocyanate, diphenyl ether-4,4'-diisocyanate, naphthylene-1,5-di Isocyanate, 1,6-hexamethylene diisocyanate, methylene-bis (4-cyclohexyl isocyanate), 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, trimethylene diisocyanate, Examples thereof include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc., and these can be used alone or in combination of two or more.

Examples of the diamine compound used as the chain extender include hydrazine, ethylenediamine, 1,2 propylene diamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, diamine compounds such as diamines having a urea group, and the like. , These can be used alone or in combination of two or more.

Examples of the diol compound used for the chain extender include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, and 1, , 3-Butandiol, Hexamethylene Glycol, Diethylene Glycol, 1,10-Decandiol, 1,3-Dimethylol Cyclohexane, 1,4-Dimethylol Cyclohexane, etc., which may be used alone or in admixture. Can also be used.

The polyurethane molded product of the present invention may be a polyurethane elastic fiber or a polyurethane film.

The polyurethane elastic fiber of the present invention can be produced by spinning a raw material solution containing the polyurethane color inhibitor and the polyurethane polymer.

As represented by the general formula (3), the polymer constituting the color inhibitor for polyurethane is a linear polyurethane compound having tertiary nitrogen in the repeating constituent unit, and therefore has an affinity with the polyurethane polymer. It has good properties, less gelation is generated, and phase separation is difficult. Therefore, in the spinning process, the spinning stability is excellent, the occurrence of migration to the fiber surface is small, the generation of scum is suppressed, that is, the generation of yarn residue is small, and the yarn breakage is also small.

Further, since the polymer composition has a specific number average molecular weight (Mn) and a relatively large molecular weight distribution (Mw / Mn), the polymer component having a relatively small molecular weight is contained in the polymer composition. And a polymer component having a relatively large molecular weight coexist. Therefore, among the color-preventing agents for polyurethanes composed of the polymer composition, those having a small molecular weight exhibit an immediate anti-coloring effect and have a large molecular weight. Has extraction resistance even after refining with an organic solvent during dough processing, repeated washing and dry cleaning of dough products, and slowly migrates to the surface of the polymer, preventing coloring over a long period of time. The sustainability of the effect can be achieved.

Dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide, N-methylpyrrolidone, etc. are used as solvents when spinning polyurethane elastic fibers using a long-chain polyurethane polymer as a raw material or when forming a film. Although mentioned, DMAc or DMF is preferable. The concentration of the long-chain polyurethane polymer is 20 to 50% by mass, particularly 30 to 40% by mass, based on the total mass of the raw material solution, which is suitable for the dry spinning method using a solvent. When molding into a film, a dry method or a wet method is preferable.

When the color inhibitor for polyurethane of the present invention is added to a polyurethane polymer, it can be easily added by various methods. For example, the polyurethane can be mixed before, during or after the polymerization, before the spinning or molding process. Further, in the polyurethane molded product of the present invention, the number average molecular weight (Mn) of the polyurethane compound (C1) is adjusted to be relatively large as described above, and the number average molecular weight (Mn) of the polyurethane compound (C2) is adjusted as described above. As a result, the polyurethane compound (C1) and the polyurethane compound (C2) are individually mixed with the polyurethane polymer after being adjusted to be relatively small so as to be produced in different production batches. It may also contain a color inhibitor for polyurethane and the polyurethane polymer.

Normally, when diol is used as the chain extender, the polyurethane elastic fiber is spun by a melt spinning method, a dry spinning method, a wet spinning method, or the like, and when diamine is used as the chain extender, the polyurethane elastic fiber is a dry spinning method. Is spun by. In the present invention, the spinning method is not particularly limited, but a dry spinning method using a solvent is preferable.

Further, a heat stabilizer, an antioxidant, an ultraviolet inhibitor, a thermal discoloration inhibitor, and a chlorine agent for sterilizing pool water such as hydrotalcite, funtite, and zinc oxide, which are known organic or inorganic compounds useful for polyurethane polymers. A polyurethane stabilizer or the like may be added to the compound. The polyurethane elastic fiber of the present invention may contain various stabilizers, pigments and the like, if necessary, as long as the effects of the present invention are not impaired. For example, benzotriazole-based and benzophenone-based agents such as BASF's "Chinubin (registered trademark)", "Irganox (registered trademark)" phenol-based antioxidant, and Sumitomo Chemical Co., Ltd. "Sumilyzer (registered trademark)". Phosphoric chemicals such as P-16, various hindered amine chemicals, inorganic pigments such as titanium oxide and carbon black, fluorine-based resin powder or silicone-based resin powder, metal soap such as magnesium stearate, and silver and zinc. And bactericides and deodorants containing these compounds, lubricants such as silicones and mineral oils, various antistatic agents such as barium sulfate, cerium oxide, betaine and phosphoric acid, etc. are added and react with polymers. It can be mentioned that it exists. Then, in order to further enhance the durability to light and various types of nitric oxide, a known nitric oxide trapping agent effective for polyurethane polymers, for example, HN-150 manufactured by Japan Finechem Co., Ltd., a thermal oxidation stabilizer, etc. A light stabilizer, for example, a light stabilizer such as "Sumisorb (registered trademark)" 300 manufactured by Sumitomo Chemical Co., Ltd. and Stub UV62 manufactured by Sabo Co., Ltd. may be additionally contained.

The polyurethane polymer composition thus obtained can be molded into a fibrous form or a film form by a conventionally known molding method.

When spinning the polyurethane elastic fiber, a known oil for polyurethane elastic fiber may be attached from the outside using an oiling device. In addition to ether-modified silicone, the oil component used here includes polyester-modified silicone, polyether-modified silicone, polyamino-modified silicone, polyorganosiloxane, mineral oil, talc, silica, mineral fine particles such as colloidal alumina, and magnesium stearate. And various substances such as higher fatty acid metal salt powder such as calcium stearate, higher aliphatic carboxylic acid, higher aliphatic alcohol, and wax solid at room temperature such as paraffin polyethylene may be used in combination.

The polyurethane elastic fiber thus obtained may be used as a bare yarn as it is in practical use, and other fibers such as polyamide fiber, wool, cotton, recycled fiber, polyester fiber and the like are conventionally known. It can also be coated with a fiber and used as a coated elastic fiber. In particular, it is preferably used in combination with a fiber material selected from the group consisting of nylon, ester, acrylic, natural fiber and cellulose derivative.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. Various evaluations were performed under the following conditions.

[Infrared absorption spectrum analysis]
The analysis of the infrared absorption spectrum in the examples was measured under the following measurement conditions.
Equipment: Shimadzu IRAfitity-IS type detector: MIRacle 10
Sample stand: ATR prism plate (diamond / ZnSe)

[Measurement of molecular weight]
The GPC analysis of various polyurethane compounds and the polymer composition obtained by mixing these polyurethane compounds was measured under the following measurement conditions, and the polystyrene-equivalent number average molecular weight (Mn) and weight average molecular weight (Mn) Mw) and molecular weight distribution (Mw / Mn) were determined.
Sample concentration: 0.1% by mass (DMF solution)
Injection volume: 50 μL
Liquid transfer pump: LC-20AD manufactured by Shimadzu Corporation
Column oven: Same as above CTO-20A
Detector: Same as above RID-20A
Eluent: DMF (LiBr 5 mM / L)
Flow rate: 1 mL / min
Column temperature: 40 ° C
Column: Showa Denko (registered trademark) GPC KD-804 (inner diameter 8 mm x length 300 mm) + KD-803 (inner diameter 8 mm x length 300 mm)

[Synthesis of high molecular weight polyurethane compound (A-1)]
A solution of 162.6 parts by mass of Nn-butyl-N, N-diethanolamine (Mw161), 222 parts by mass of isophorone diisocyanate (Mw222) and 381 parts by mass of dry dimethylacetamide in dry nitrogen gas at room temperature. Under stirring, 0.1 part by mass of dibutyltin dilaurate was added as a catalyst, and after stirring for 2 hours, the temperature inside the system was raised to 70 ° C., and the reaction was further carried out for 6 hours, and the reaction solution was unreacted in the infrared absorption spectrum. After confirming that the absorption of the isocyanate group at 2270 cm- ¹ had disappeared, the reaction was terminated.
The results of analysis of the molecular weight of the synthetic compound (A-1) by GPC are that the polystyrene equivalent number average molecular weight (Mn) is 52400, the weight average molecular weight (Mw) is 65918, and the molecular weight distribution (Mw / Mn) is 1.258. Met.

[Synthesis of high molecular weight polyurethane compounds (A-2) to (A-4)]
Table 1 shows the charged molar ratio and the molecular weight measurement results of various high molecular weight polyurethane compounds (A-2, A-3, A-4) synthesized in the same manner.

[Synthesis of low molecular weight polyurethane compound (B-1)]
A solution of 185.2 parts by mass of Nn-butyl-N, N-diethanolamine (Mw161), 222 parts by mass of isophorone diisocyanate (Mw222) and 407.2 parts by mass of dry dimethylacetamide in dry nitrogen gas. Under stirring at room temperature, 0.1 part by mass of dibutyltin dilaurate was added as a catalyst, and after stirring for 2 hours, the temperature inside the system was raised to 70 ° C., and the reaction was further carried out for 5 hours. The reaction was terminated after confirming that the absorption of the unreacted isocyanate group at 2270 cm- ¹ had disappeared.
The results of analysis of the molecular weight of this synthetic compound (B-1) by GPC show that the polystyrene equivalent number average molecular weight Mn is 18,052, the weight average molecular weight (Mw) is 22,310, and the molecular weight distribution (Mw / Mn) is 1. It was .236.

[Synthesis of low molecular weight polyurethane compounds (B-2) to (B-4)]
Table 1 shows various low molecular weight polyurethane compounds (B-2, B-3, B-4) synthesized in the same manner.

[Manufacturing example of color inhibitor for polyurethane]
(Polyurethane color inhibitor (AB-1) to (AB-11))
The above high molecular weight polyurethane compounds (A-1) to (A-4) and low molecular weight polyurethane compounds (B-1) to (B-4) are mixed at the mixed mass ratio shown in Table 2 and shown in Table 2. Anticolorants (AB-1) to (AB-11) for polyurethane having a molecular weight distribution of (Mw / Mn) were prepared. The results of molecular weight analysis by GPC are shown in Table 2.

(Polyurethane anticoloring agents (C-1) to (C-10))
The above high molecular weight polyurethane compounds (A-1) to (A-4) and low molecular weight polyurethane compounds (B-1) to (B-4) are mixed at the mixed mass ratio shown in Table 2 and shown in Table 2. Anticolorants (C-1) to (C-10) for polyurethane having a molecular weight distribution of (Mw / Mn) were prepared.
The results of molecular weight analysis by GPC are shown in Table 2.

(Coloring inhibitor for polyurethane (C-11))
A polyurethane compound (polyurethane color inhibitor (C-11)) was synthesized as follows in accordance with Example 1 of JP-A-6-78483.
100 parts by mass of N, N-bis (2-hydroxypropyl) -1,1-dimethylpropylamine and 79.3 parts by mass of N-butyl-bis (2-hydroxyethyl) amine and 198.7 parts by mass of isocyanate A solution of diisocyanate and 378 parts by mass of N, N-dimethylacetamide was stirred in dry nitrogen gas at room temperature, 0.15 parts by mass of dibutyltin dilaurate was added as a catalyst, and after stirring for 1 hour, the system was added. The temperature is increased to 70 ° C., and the reaction is carried out for another 5 hours. After confirming on the infrared absorption spectrum that the absorption of the unreacted isocyanate group at 2270 cm- ¹ has disappeared in the reaction solution, the reaction is terminated.
As shown in Table 2, the results of analysis of the molecular weight of this synthetic compound (C-11) by GPC are that the polystyrene-equivalent number average molecular weight Mn is 26,723, the weight average molecular weight (Mw) is 34,072, and the molecular weight distribution degree. (Mw / Mn) was 1.275. The present synthetic compound (C-11) was used as a color inhibitor for polyurethane (C-11).

[Manufacturing of undiluted polyurethane urea]
400 parts by mass of polytetramethylene ether diol having a number average molecular weight of 1,800 and 91.7 parts by mass of 4,4'-diphenylmethane diisocyanate were reacted in a dry nitrogen atmosphere at 80 ° C. for 3 hours under stirring. Urethane prepolymers having isocyanate groups at both ends were obtained. After cooling this to room temperature, 720 parts by mass of DMAc was added and dissolved to prepare a urethane prepolymer solution. On the other hand, 8.11 parts by mass of ethylenediamine and 1.37 parts by mass of diethylamine were dissolved in 390 parts by mass of DMAc, and this was added to the urethane prepolymer solution at room temperature with vigorous stirring to obtain a viscosity of 370 Pa · s (30 ° C.). Polyurethane urea stock solution (A) (concentration 31.1% by mass) was obtained.

1 part by mass% of 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-t-butylbenzoyl) isocyanurate with respect to 100 parts by mass of the polyurethane urea solid content of the polyurethane urea stock solution (A). (Product name Songnox (registered trademark) 1790 manufactured by Songwon Co., Ltd.) was mixed uniformly with stirring to prepare a stock solution (PUUB) for polyurethane urea spinning.

[Production example of polyurethane elastic fiber]
(Example 1)
It was obtained by uniformly stirring and mixing 3.0 parts by mass of the solid content of the polyurethane coloring inhibitor (AB-1) in Table 2 with 100 parts by mass of the solid content of the above-mentioned undiluted solution for polyurethane urea spinning (PUUB). After defoaming the undiluted solution for spinning, 16 spinning caps (each cap has 4 pores.
) Was pushed out into hot air at about 230 ° C. to evaporate the DMAc solvent. Dried yarn is falsely twisted, oiled with dimethylsilicon as the main component is applied on an oiling roller via a god de trawler, wound on a paper tube at a speed of 700 m / min, and treated with 44 decitex / 4 filament polyurethane. Elastic fibers were obtained.

(Examples 2 to 11)
The same as in Example 1 except that the color inhibitor for polyurethane (AB-1) used in Example 1 was changed to the color inhibitor for polyurethane (AB-2) to (AB-11). Polyurethane elastic fibers of 2 to 11 44 decitex / 4 filaments were obtained.

(Comparative Example 1)
Comparison was carried out in the same manner as in Example 1 except that the polyurethane urea spinning stock solution (PUUB) was used as the spinning stock solution without using the polyurethane coloring inhibitor (AB-1) used in Example 1. Polyurethane elastic fibers of 44 decitex / 4 filaments of Example 1 were obtained.

(Comparative Examples 2 to 12)
Comparative Example in the same manner as in Example 1 except that the color inhibitor for polyurethane (AB-1) used in Example 1 was changed to the color inhibitor for polyurethane (C-1) to (C-11). Polyurethane elastic fibers of 2 to 12 44 decitex / 4 filaments were obtained.

[Evaluation of polyurethane elastic fiber]
The polyurethane elastic fibers thus produced were evaluated in various ways according to the following methods.

(Spinning stability)
Table 3 shows the results of spinning for 40 hours using the undiluted solution for spinning produced by the method described above and measuring the number of yarn breaks (times / hour). The smaller the number of thread breaks, the more stable the productivity.

(Amount of scum)
After leaving the 44 decitex / 4 filament polyurethane elastic fiber in an atmosphere of 45 ° C. and 65% RH for 30 days, the paper tube is placed on a satin roller, and the elastic fiber is rotated at a roller surface speed of 40 m / min. Is sent out. The sent out elastic fibers are wound on a satin roller of the same diameter installed at a distance of 50 cm. A razor blade was set up at an intermediate point 25 cm from the elastic yarn to be fed so that the yarn angle was 115 degrees, and the surface speed on the winding roller was set to 70 m / min. After running the elastic fiber on the razor blade for 1 hour, visually judge the amount of white scum adhering to the razor blade (manufactured by NT Co., Ltd .: NT-L type blade part number L-300) from 1st grade to 5th grade. Did. The results are shown in Table 3.
Grade 5: No adhesion to the razor blade.
Grade 4: There is a slight adhesion to the razor blade.
Grade 3: There is some adhesion to the razor blade.
Level 2: Slightly attached to the razor blade.
Grade 1: There is a large amount of deposits on the razor blade.

(Thread strength of polyurethane elastic fiber)
The obtained 44-decitex / 4-filament polyurethane elastic fiber was subjected to a tensile tester (manufactured by Orientec Co., Ltd .: UTM-3-100 type) at 20 ° C. under a 65% RH atmosphere and 1000 at a thread sample length of 5 cm. The breaking strength (that is, the yarn strength) was measured under the condition of the strain rate of% / min. The results are shown in Table 3.

(The number of seconds for thermal cutting)
The time (seconds) from pressing a 44-decitex / 4-filament polyurethane elastic fiber against a hot body at 190 ° C. under 50% elongation to cutting was measured. The results are shown in Table 3.

(Washing process (thread process A))
One week after the end of spinning, a 44-decitex / 4-filament polyurethane elastic fiber yarn was boiled for 1 hour under 50% elongation, and then 1.0 g / L of a surfactant (Kao Corporation One Pack Attack Highly Active Bio EX) was added. It was carried out by a method of washing at 40 ° C. for 40 minutes, washing with water, and drying at 45 ° C. for 15 minutes in a washing solution dissolved in the above concentration.

(Strength retention rate after light resistance test)
A light resistance test was carried out on the polyurethane elastic fiber after the washing treatment (thread treatment A), and the strength retention rate was evaluated by measuring the thread strength before and after the light resistance test. In the light resistance test, the polyurethane elastic fiber was irradiated with ultraviolet rays for 25 hours using a fade meter (U48AU-B type manufactured by Suga Test Instruments Co., Ltd.). Fracture using a tensile tester (manufactured by Orientec Co., Ltd .: UTM-3-100 type) under the conditions of a yarn sample length of 5 cm and a strain rate of 1000% / min at 20 ° C. and a 65% RH atmosphere. The strength (ie, yarn strength) was measured. Here, the strength retention rate was calculated by the following equation.
Strong retention rate (%) = (thread strength after UV irradiation / thread strength before UV irradiation) x 100
The results are shown in Table 3.

(NOx gas coloration degree)
The degree of coloring with NOx gas was evaluated for the yarn wound with the polyurethane elastic fiber after the washing treatment (thread treatment A).
A strong test of 5 units was performed according to JIS L 0855-2005. The degree of coloring was visually discriminated by dividing into 5 ranks of 1st grade ... brown, 2nd grade ... tan, 3rd grade ... yellow, 4th grade ... pale yellow, 5th grade ... uncolored. .. However, when the hue is in the middle of each grade, it is displayed by subtracting 0.5 grade from the upper grade. The results are shown in Table 3.

(Combustion gas coloration)
The degree of coloration due to combustion gas was evaluated according to AATCC-23 for the yarn wound with polyurethane elastic fibers after the washing treatment (thread treatment A).
The degree of coloration after exposure to the combustion gas was visually determined by dividing it into 5 ranks of 1st grade ... tan, 2nd grade ... yellow, 3rd grade ... pale yellow, 4th grade ... slightly yellow, 5th grade ... uncolored. However, when the hue is in the middle of each grade, it is displayed by subtracting 0.5 grade from the upper grade. The results are shown in Table 3.

(Chlorine bleach coloring degree)
The yarn wound with polyurethane elastic fibers after washing treatment (thread treatment A) is boiled in ion-exchanged water for 1 hour, and then a chlorine-based clothing bleach manufactured by Kao Corporation (trade name: Highter (trade name: Highter). (Registered trademark)) 10 mL was immersed in a solution mixed with 1 L of water for 10 hours under the condition of 25 ° C., washed in running water for 1 hour, dried at room temperature, and then the degree of coloring was evaluated. The degree of coloring is visually discriminated by dividing into 5 ranks: 1st grade ... reddish brown, 2nd grade ... red, 3rd grade ... light red, 4th grade ... slightly colored, 5th grade ... uncolored. And displayed. However, when the hue is in the middle of each grade, it is displayed by subtracting 0.5 grade from the upper grade. The results are shown in Table 3.

(Washing treatment (thread treatment A) followed by dry cleaning treatment (thread treatment B))
The polyurethane elastic fibers of Examples 1 to 11 and Comparative Examples 1 to 12 were subjected to the washing treatment (thread treatment A), and subsequently immersed in a perchlorethylene solution at 50 ° C. for 2 hours under 50% elongation. Then, it was dried at 45 ° C. for 15 minutes (dry cleaning treatment (thread treatment B)). The bath ratio for immersion in the perchlorethylene solution was 1: 1000.
With respect to the polyurethane elastic fiber subjected to this dry cleaning treatment (thread treatment B), the NOx gas coloring degree, the combustion gas coloring degree, and the chlorine bleach coloring degree were evaluated in the same manner as in the above-mentioned example.
The results are shown in Table 4.

(After thread treatment A and thread treatment B, leave for 60 days (thread treatment C))
The polyurethane elastic fibers subjected to the washing treatment (thread treatment A) and the dry cleaning treatment (thread treatment B) were left to stand for 60 days (thread treatment C) at 20 ° C. in a 65% RH atmosphere.
The NOx gas coloration degree, the combustion gas coloration degree, and the chlorine bleach coloration degree of the polyurethane elastic fiber left to stand for 60 days (thread treatment C) were evaluated in the same manner as in the above example. The results are shown in Table 4.

It has been confirmed that the color-preventing agent for polyurethane of the present invention has an immediate effect of color-preventing and has a long-lasting color-preventing effect even after repeated washing and dry-cleaning washing.

According to the present invention, it is possible to provide a coloring inhibitor for polyurethane which has an immediate effect of preventing coloring and has a long-lasting effect of preventing coloring even after repeated washing or dry cleaning washing.
In the present invention, the polymer composition having the structural unit represented by the general formula (3) can be used as a color inhibitor in the production of a polyurethane molded product.

Claims (7)

A color inhibitor for polyurethane composed of a polymer composition having a structural unit represented by the following general formula (3), wherein the number average molecular weight (Mn) of the polymer composition is 10,000 ≦ Mn ≦ 80,000. , A color inhibitor for polyurethane having a molecular weight distribution (Mw / Mn) calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw) of 1.30 or more and 2.55 or less.
-[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B) . It is a group, i is an integer of 1 to 4, and j is an integer of 1 to 4.) The organic diisocyanate (B) is a linear aliphatic diisocyanate, a branched chain aliphatic diisocyanate, a cyclic aliphatic diisocyanate, an aliphatic diisocyanate having an aromatic ring, or an aromatic diisocyanate. The anticoloring agent for polyurethane according to claim 1, which is a nalto. The color inhibitor for polyurethane according to claim 1 or 2, wherein R ³ in the general formula (3) is an alkyl group having 3 to 7 carbon atoms. The color inhibitor for polyurethane according to any one of claims 1 to 3, wherein i is 1 and j is 1 in the general formula (3). A polyurethane compound (C1) having a structural unit represented by the following general formula (3) and a number average molecular weight (Mn) of the polyurethane compound (C1) having a structural unit represented by the following general formula (3). A method for producing a color inhibitor for polyurethane, which is mixed with a polyurethane compound (C2) having a smaller number average molecular weight (Mn). -[(OR ¹ ) _i- N (R ³ )-(R ^2- O) _j- CONHR ⁴ NHCO]-... (3)
(In the formula, R ¹ and R ² are independently alkylene groups having 2 to 5 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is the residue of the organic diisocyanate (B). The group, i is an integer of 1 to 4, and j is an integer of 1 to 4.) A polyurethane molded product containing the polyurethane color inhibitor according to any one of claims 1 to 4 and a polyurethane polymer. The polyurethane molded product according to claim 6, wherein the polyurethane molded product is a polyurethane elastic fiber or a polyurethane film.