JPH08158155A - Polyurethane elastic fiber - Google Patents

Abstract

PURPOSE: To obtain a polyurethane elastic fiber comprising a high molecular polyol, an organic polyisocyanate, and a low molecular polyol, having specific urethane bonds, and excellent in heat resistance and elastic recovery. CONSTITUTION: A polyurethane elastomer comprising a high molecular polyol such as polytetramethylene ether glycol, polyethylene adipate or polyesterpolycarbonatepolyol, an organic polyisocyanate, and a low molecular polyol such as 1,2,5-bis(2-hydroxyethoxycarbonyl) hydroquinone, having a branched structure, and having urethane bonds wherein 0.1-50% of the urethane bonds comprise aromatic hydroxyl groups and aromatic isocyanate groups, is melt-spun to obtain the objective polyurethane elastic fiber. The elastic fiber has the heat resistance of the formula in a value of <=50%, and exhibits characteristics little in deformation and excellent in heat resistance. The heat resistance is determined by heating an elastic fiber (40d) under an elongation of 100% at +60 deg.C (dry heating) for 1min., measuring the length of a specimen when cooled and relaxed, and subsequently applying the measured result to the equality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastic fiber having excellent elastic recovery and heat resistance, and more specifically, it has a branched structure and has a total urethane bond of
The present invention relates to a polyurethane elastic fiber produced by spinning a polyurethane elastomer in which 0.1 to 50% is a urethane bond composed of an aromatic hydroxyl group and an aromatic isocyanate group.

[0002]

2. Description of the Related Art Conventionally, polymer polyols, organic polyisocyanates and low molecular weight polyols have often been used for producing polyurethane elastic fibers, and the elasticity of polyurethane elastic fibers produced from these is often used. The recoverability and heat resistance were not always satisfactory, and their weaknesses meant that they had to be restricted in their applications.

Therefore, attempts have been made to obtain polyurethane having excellent heat resistance and elastic recovery, for example, Japanese Patent Publication No. 63-53287, Japanese Patent Publication No. 63-53288, and Japanese Patent Laid-Open No. 3-213515. However, the performance cannot be said to be satisfactory. In other words, these attempts are aimed at improving performance by cross-linking consisting of allophanate bonds and burette bonds, but the heat resistance of these bonds is insufficient, and therefore the heat resistance of the polyurethane containing these bonds is also sufficient. It cannot be said that.

On the other hand, a rubber crosslinked by vulcanization or the like, which is different from the polyurethane elastic body in nature, is excellent in heat resistance and elastic recovery due to its chemical bond crosslink having high heat resistance. However, it is very difficult to mold such a chemically crosslinked polymer, especially to form elastic fibers.

[0005]

Accordingly, the object of the present invention is to provide a polyurethane having excellent heat resistance and elastic recovery as high as that of chemically crosslinked rubber from high molecular weight polyol, organic polyisocyanate and low molecular weight polyol. To provide elastic fibers.

[0006]

That is, the present invention provides an elastic fiber produced by spinning a polyurethane elastomer comprising a high molecular weight polyol, an organic polyisocyanate, and a low molecular weight polyol. The polyurethane elastomer forming the elastic fiber has a branched structure,
In addition, 0.1 to 50% of all urethane bonds are urethane bonds composed of aromatic hydroxyl groups and aromatic isocyanate groups, and the heat resistance of the elastic fiber represented by the following formula is 50%.
The present invention relates to a polyurethane elastic fiber characterized by the following. Heat resistance (%) = {(length after heating-initial length) / initial length}
× 100 Elastic fiber (40 denier) at 100 ℃ under 100% elongation
Heat for 1 minute with (dry heat), measure the sample length (length after heating) when relaxing after cooling, and determine the heat resistance from the above formula.

The polymer polyol used in the present invention includes a polyether polyol represented by polytetramethylene ether glycol, a polyester polyol represented by polyethylene adipate, and a polycaprolactone polyol. Polyester polyester carbonate exemplified by a reaction product of polyester glycol such as polycaprolactone and alkylene carbonate.
And ethylene carbonate are reacted with polyhydric alcohol such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and the resulting reaction mixture is then treated with adipic acid and azelaine. Acid, those reacted with an organic dicarboxylic acid such as sebacic acid, and 1,
4-butanediol, 1,6-hexanediol, 2,
A polyhydroxyl compound such as 2-dimethyl-1,3-propanediol, 1,8-octanediol and the like;
Examples thereof include polycarbonate carbonate obtained by transesterification with an aryl carbonate, for example, diphenyl carbonate. These may be used alone or in combination of two or more.

As the organic diisocyanate,
4,4'-diphenylmethane diisocyanate, 1,5
-Naphthalene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate,
Aromatic diisocyanates such as 2,6-tolylene diisocyanate, hexamethylene diisocyanate, 1,4-
Aliphatic diisocyanates such as cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate can be mentioned. These may be used alone or in a mixture of two or more, but 0.1 to 50% of all urethane bonds of the polyurethane obtained by using these are aromatic hydroxyl group and aromatic It must be a urethane bond composed of an isocyanate group.

As the low molecular weight polyol, a compound represented by Chemical formula 1 or the like can be used.

[0010]

Embedded image (In the chemical formula 1, Ar is selected from trivalent or higher monocyclic aromatic groups, condensed polycyclic aromatic groups, and non-condensed polycyclic aromatic groups in which aromatic groups are directly or linked to each other by a bonding member. Represents a heterocyclic group, and the aromatic group as used herein includes a heterocyclic aromatic group,
Substituents such as an alkyl group, an alkoxy group, and a halogen group may be attached. X ₁ and X ₂ may be the same or different, and are a direct bond, —O—, —S—, —C.
Represents a binding member such as OO-, -OCO-, -OCOO-, -CO-. Z ₁ and Z ₂ may be the same or different and are —O—, —S—, —COO—, —OCO—, —O.
Represents a bonding member such as COO- and -CO-. Y ₁ , Y ₂ , Y
₃ , Y ₄ may be the same or different and each represents an alkylene group having 1 to 6 carbon atoms. n and m may be the same or different and represent an integer of 0 to 3. R represents a hydroxyl group directly bonded to the aromatic ring. a represents an integer of 1 or more. )

Specific examples of the compound are 2,5-
Examples thereof include bis (2-hydroxyethoxycarbonyl) hydroquinone, 3,5-bis (2-hydroxyethoxycarbonyl) phenol, and 4,4′-bis (2-hydroxyethoxy) -2,2′-dihydroxy-diphenylmethane. Other examples include 2- (4-hydroxyphenyl) -1,4-butanediol and the like.

These compounds are ethylene glycol, propylene glycol, 1,4-butanediol and 1,6.
-Hexanediol, hydroxyethylhydroquinone, cyclohexanedimethanol, bis (2-hydroxyethyl) terephthalate, bis (2-hydroxyethyl) isophthalate, bis (2-hydroxyethyl) phthalate, and o, o'-dihydroxy. Diphenylmethane, o, p'-dihydroxydiphenylmethane, p,
ethylene oxide, propylene oxide of p′-dihydroxydiphenylmethane, and mixtures thereof,
It may be used in combination with an adduct such as butylene oxide. However, it is necessary that 0.1 to 50% of all urethane bonds of the polyurethane obtained by using these are urethane bonds composed of an aromatic hydroxyl group and an aromatic isocyanate group.

The ratio of the high molecular weight polyol and the low molecular weight polyol in the present invention can be variously changed depending on the respective molecular weights and desired physical properties of the polyurethane. Further, the number of isocyanate groups (NCO / OH) of the organic polyisocyanate is 0.80 with respect to the total number of hydroxyl groups (including aromatic hydroxyl groups) of both.
The range of to 1.25 is desirable, and 0.95 is preferable.
More preferably, it is 1.15. If this ratio is too small, the branched structure becomes insufficient and the heat resistance and the elastic recovery property are reduced, which is not preferable.
This is not preferable because it lowers productivity.

In the present invention, since the trifunctional or higher functional low molecular weight polyol as shown in Chemical formula 1 is used, the obtained polyurethane elastomer has a structure in which the hard segment portion is crosslinked. Generally, a polyurethane elastomer restrains a soft segment by the cohesive force of hydrogen bond of a hard segment and develops rubber-like properties. However, if the cohesive force of this hard segment is cross-linking by a stronger chemical bond, it is elastic. Recoverability and heat resistance are improved. This crosslinking point in the present invention is mainly a urethane bond, and this bond has a higher heat resistance than an allophanate bond or a burette bond, and as a result, the polyurethane elastomer obtained according to the present invention also has a high heat resistance.

The polyurethane elastomer of the present invention has a crosslinking point in the hard segment portion by a urethane bond, and this crosslinking point bond is preferably a urethane bond composed of an aromatic hydroxyl group and an aromatic isocyanate group from the viewpoint of moldability. .

In the polyurethane elastomer of the present invention, it is preferable that 0.1 to 50% of all urethane bonds are urethane bonds composed of aromatic hydroxyl groups and aromatic isocyanate groups. If this is too small, sufficient elastic recovery and heat resistance cannot be obtained. On the other hand, if it is too large, the moldability becomes poor, which is not preferable.

The polyurethane elastomer of the present invention is manufactured by using a known urethanization technique such as a melting method or a solution method, but it is preferable to manufacture it by a melting method in consideration of cost, working environment and the like. For example, a high-molecular polyol and a low-molecular-weight polyol compound are preheated to about 40 to 100 ° C., and then the isocyanate group of the organic polyisocyanate is used with respect to the total number of hydroxyl groups (including aromatic hydroxyl groups) of the mixture.
After adding an amount of organic polyisocyanate in an amount such that the number of base groups is 0.95 to 1.15 and stirring vigorously for a short time,
The polyurethane is obtained by leaving it under nitrogen at about 50 to 180 ° C. A method of obtaining polyurethane via a urethane prepolymer can also be used. If necessary, other trifunctional components such as triol and triisocyanate may be used in combination.

In the production of polyurethane, a catalyst which is usually used in the production of polyurethane,
Optional components such as activators, defoamers, lubricants, stabilizers such as UV absorbers and anti-yellowing agents, pigments, antistatic agents, surface treatment agents, flame retardants, mildew-proofing agents, and reinforcing agents as needed. Can be used.

The polyurethane elastic fiber of the present invention can be produced by a spinning method such as melt spinning, dry spinning, and wet spinning. From the viewpoints of cost, fiber homogeneity, etc., melt spinning is desirable.

The spinning apparatus and spinning conditions used for melt spinning the polyurethane elastomer of the present invention may vary depending on the content of the polyurethane, the intended fiber thickness, the polymerization method, etc. The polymer is supplied to the extrusion type spinning device, and the spinning temperature is 180 to 240.
It is preferable to carry out spinning at a temperature of 1000 ° C. and a spinning speed of 1000 m / min or less, particularly 600 m / min or less. The apparent draft rate is 50 or more, preferably 100 or more. The spinning tension when the spun yarn is wound on the bobbin by the winding machine is 0.1 g / d or less, preferably 0.05 g / d or less.

[0021] Further, the wound-up yarn is hard-treated under low humidity.
It is preferable to perform heat treatment in the vicinity of the glass transition temperature of the hard segment so that the phase separation of the hard segment and the soft segment is sufficiently advanced. Generally, polyurethane elastic fibers having a thickness of about 5 to 100 denier // filament can be obtained by these methods. The polyurethane elastic fibers used in the present invention have a denier in the range of 15 to 100. Is suitable, and preferably 40 to 80. These elastic fibers are used in the state of covering yarn or bare yarn.

The polyurethane elastic fiber of the present invention has a heat resistance of 50% or less represented by the following formula. When the value is larger than 50%, permanent deformation due to heat during post-processing is large, which leads to insufficient power in products. Heat resistance (%) = {(length after heating-initial length) / initial length}
× 100 Elastic fiber (40 denier) at 100 ℃ under 100% elongation
After heating for 1 minute (dry heat) and cooling and then relaxing, measure the sample length and determine the heat resistance from the above formula.

[0023]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. Moreover, the part in an Example represents a weight part. Further, in the following examples, logarithmic viscosity, heat resistance and elastic recovery rate were measured by the following methods.

<< Measurement of Logarithmic Viscosity >> Elastic Fiber 0.0750
g was dissolved in 25 ml of a 0.05N-dibutylamine / N, N-dimethylacetamide solvent, 10 ml of this polymer solution was placed in an Ostwald viscometer, and the number of seconds dropped was measured in a thermostat at 30 ° C. The logarithmic viscosity (η _inh ) was obtained from the above. η _inh = {ln (t / t ₀ )} / C t: polymer solution drop time (sec) t ₀ : solvent drop time (sec) C: polymer solution concentration (g / dl) or more The logarithmic viscosity of the elastic fiber was measured by the method.

<< Measurement of heat resistance >> Elastic fiber (40 denier
(1) was heated for 1 minute at 160 ° C. (dry heat) under 100% elongation, and after cooling, the sample length when relaxed was measured, and the heat resistance was determined from the following equation. Heat resistance (%) = {(length after heating-initial length) / initial length}
× 100 Since the polyurethane elastic fiber having excellent heat resistance is unlikely to be permanently deformed by heating under elongation, the heat resistance defined by the above formula has a small value.

<< Measurement of Elastic Recovery Rate >> Elastic fiber (40 denier) was stretched 300%, relaxed, and then stretched 300% to measure the stress at 150% extension, and at the first 150% extension. The ratio of to the stress was calculated from the following equation. Elastic recovery rate (%) = (stress at the second 150% elongation /
Stress at the first 150% elongation) × 100 Since polyurethane elastic fibers having excellent elastic recovery are less likely to suffer structural destruction due to expansion, the elastic recovery rate defined by the above formula has a large value.

Examples 1 and 2 100 parts of polybutylene adipate (abbreviated as PBA) having hydroxyl groups at both ends and a number average molecular weight of 2000, 2,5-bis (2-hydroxyethoxycarbonyl) hydroquinone (abbreviated as compound 1) ) 1.43 parts, bis (2-hydroxyethyl) terephthalate (abbreviated as BHET) 24.1
Polyurethane elastomer obtained by the one-shot method from 3 parts and 41.1 parts of diphenylmethane diisocyanate (abbreviated as MDI) (NCO / OH = 1.06) was melt-spun to obtain 40 denier / 4 filaments. An elastic fiber was obtained.
The yarn without heat treatment was subjected to measurement as Example 1, and the yarn that was heat treated at 120 ° C. for 16 hours was used as Example 2.

Example 3-PBA 100 parts, Compound 1 2.86 parts, 1,4-butanediol (abbreviated as BD) 8.1 parts, MDI 42.
The same experiment as in Example 1 was carried out except that the polymerization was carried out using 4 parts (NCO / OH = 1.06) (only the yarn after heat treatment).

Example 4-PBA 100 parts, 3,5-bis (2-hydroxyethoxycarbonyl) phenol (abbreviated as compound 2) 2.7
Part, BHET 22.86 part, MDI 41.1 part (N
The same experiment as in Example 1 was carried out except that the polymerization was carried out using CO / OH = 1.06) (only the yarn after heat treatment).

-Comparative Example 1-PBA 100 parts, BHET 25.4 parts, MDI 3
The same experiment as in Example 1 was carried out except that the polymerization was carried out using 9.75 parts (NCO / OH = 1.06) (only the yarn after heat treatment).

Comparative Example 2-PBA 100 parts, 1,3,5-tris (2-hydroxyethoxycarbonyl) benzene (abbreviated as compound 3)
3.42 parts, BHET 22.86 parts, MDI 41.1
The same polymerization as in Example 1 was carried out using parts (NCO / OH = 1.06). However, in the latter stage of polymerization, gelation occurs,
Handling became difficult. The gelled polymer could not be melt spun. The results of each example are shown in Table 1.

[0032]

[Table 1] In the table, * indicates the proportion of urethane bonds composed of aromatic hydroxyl groups and aromatic isocyanate groups, out of all urethane bonds.

[0033]

According to the present invention, there is provided an elastic fiber produced by melt spinning a polyurethane elastomer comprising a high molecular weight polyol, an organic polyisocyanate and a low molecular weight polyol, the polyurethane elastomer and the elastic fiber. Has a branched structure, and 0.1 to 50% of all urethane bonds is a urethane bond composed of an aromatic hydroxyl group and an aromatic isocyanate group, a polyurethane elastic fiber excellent in heat resistance and elastic recovery is obtained. Obtainable.

Claims (1)

[Claims] 1. An elastic fiber produced by spinning a polyurethane elastomer comprising a high molecular weight polyol, an organic polyisocyanate, and a low molecular weight polyol, wherein the polyurethane elastomer constituting the elastic fiber is Has a branched structure, and among all urethane bonds,
0.1 to 50% is a urethane bond composed of an aromatic hydroxyl group and an aromatic isocyanate group, and the heat resistance of the elastic fiber represented by the following formula is 50% or less. Heat resistance (%) = {(length after heating-initial length) / initial length}
× 100 Elastic fiber (40 denier) at 100 ℃ under 100% elongation
After heating for 1 minute (dry heat) and cooling and then relaxing, measure the sample length and determine the heat resistance from the above formula.