JP2805938B2 - Polyurethane / polyamide eccentric conjugate fiber and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a self-crimping conjugate fiber comprising a polyurethane and a polyamide. More specifically, excellent recovery stress properties, especially useful as a stocking and tricot material excellent in fit and transparency,
The present invention relates to an eccentric polyurethane / polyamide fiber.

[Prior art] Self-crimping conjugate fibers obtained by eccentrically compounding polyurethane and polycapramid can be used as a knitted fabric having excellent crimping properties and transparency, and are therefore highly used as materials for high-grade stockings. Has been evaluated.

Examples of the polyurethane component in the composite fiber include a polyol, a polyether composed of polyalkylene oxide, polytetrahydrofuran, and the like; a polylactone obtained by ring-opening polymerization of ε-caprolactone; an acid such as adipic acid and glutaric acid; ethylene glycol; Polyesters obtained by condensation polymerization from glycols such as glycols; or polyester carbonates, obtained by reacting these polyols with diisocyanates and conducting chain extension with low molecular weight diols, hydrazine or ethylenediamines. Elastic polyurethanes are known.

Among these elastic polyurethanes, an elastic polyurethane containing a polycarbonate-based polyurethane which is excellent in peel resistance from a polyamide component and relatively excellent in heat resistance is considered to be good (Japanese Patent Publication No. 57-34370, Japanese Patent Publication No. Kimiaki 55
No. -22570).

In these conventional elastic polyurethanes for composite fibers, polyurethanes composed of a polyol having a molecular weight of about 500 to 3,000 are used. Even in the case of using a copolymerized polyurethane in which different polyol units are used in combination, it is generally considered to be preferable to use the same polyol having the same number average molecular weight from the viewpoint of ease of the polyurethane polymerization reaction. Also, it has been generally practiced to increase the number average molecular weight of a polyester-based polyol having excellent elongation characteristics of the polymer itself.

For example, in the former of the above publication, the use of a mixed polyol of a polycarbonate having a number average molecular weight of 1500 and a polybutylene adipate having a number average molecular weight of 1500, and in the latter,
Polycarbonate with a number average molecular weight of 1000 and a number average molecular weight of 20
The use of mixed polyols with polycaprolactone of 00 is described.

[Problems to be Solved by the Invention] Even if an eccentric conjugate fiber is produced using the above-mentioned conventional polyurethane component, a considerably excellent coiled crimp can be obtained. There is a demand for a polyurethane / polyamide-based conjugate fiber that has a higher strength and a higher fit.

Accordingly, an object of the present invention is to provide a polyurethane / polyamide eccentric conjugate fiber which can enhance the recovery stress characteristics after crimping without impairing the excellent elongation / recovery characteristics of the polyurethane elastic body. .

[Means for Solving the Problems] To achieve the above object, a polyurethane-polyamide conjugate fiber according to claim 1 of the present invention is an eccentric conjugate fiber comprising a polyurethane component and a polyamide component, wherein the polyurethane component is The elastic polyurethane to be constituted contains at least two or more kinds of polyols having different number average molecular weights as a soft segment constitution polyol, and contains a polycarbonate ester polyol as a polyol having a higher number average molecular weight among the polyols, and A polyurethane / polyamide eccentric conjugate fiber, wherein the polyol has a number average molecular weight satisfying the following formulas (1) and (2) simultaneously.

_{1000 ≦ MW ≦ 3000 ... (1} ) 1.3 ≦ M W (A) / M W (B) ≦ 6 ... (2) ( provided that, _MW is the average of the construction polyol number average molecular weight of the elastic polyurethane, M _W (A ) Indicates the number average molecular weight of the polycarbonate polyol having the higher number average molecular weight,
Further, the number average molecular weight of M _W (B) low of number average molecular weight towards the polyol represents respectively. Further, in the method for producing an eccentric polyurethane / polyamide fiber according to claim 3 of the present invention, when the eccentric polyurethane / polyamide fiber according to claim 1 is produced by melt-spinning a polyurethane component and a polyamide component, 100% tensile stress of 125 as the polyurethane component
It is characterized by using an elastic polyurethane having a kgf / cm ² or more.

The molecular weight in the following text means a number average molecular weight.

The elastic polyurethane used as the polyurethane component in the present invention uses a polycarbonate-based polyol as at least a part of the soft segment-structured polyol, and the polyol having a high molecular weight needs to be a polycarbonate-based polyol. It is. The polyol having a lower molecular weight may be a polycarbonate-based polyol, or may be another polyol. As other polyols, polyester-based polyols, polyether-based polyols and the like are used. The polyester-based polyol may be a polylactone-based polyol.

As described above, the polyol having a higher molecular weight is required to be a polycarbonate-based polyol in order to sufficiently improve the recovery stress characteristics of the conjugate fiber. vice versa,
Polyols having a higher molecular weight is Polyols other than polycarbonate-based polyol, the molecular weight ratio [M _W
(A) / M _W (B)] is less than 1.0, the recovery stress characteristics of the conjugate fiber cannot be sufficiently improved.

This elastic polyurethane may be a copolymer and / or a mixture of polyurethanes containing polyols having different molecular weights. The content of the carbonate-based polyurethane in the polyurethane copolymer and / or the mixture is preferably 20% by weight or more from the viewpoint of adhesion to the polyamide component and the like.

The soft segment constituent polyol needs to be composed of at least two or more kinds of polyols having different molecular weights. In order to obtain a desired effect by making the molecular weights of these polyols different, a polyol having a larger molecular weight and a polyol having a smaller molecular weight are respectively:
It is desirable that the content be 20% by weight or more, more preferably 30% by weight or more of the total polyol. Further, a small amount of polyol having a structure ratio of less than 10% by weight may be substantially excluded. When three or more polyols having different molecular weights are used, the polyol having the largest molecular weight and the polyol having the smallest molecular weight need only satisfy the molecular weight conditions of the above formulas (1) and (2). .

Polyester and polyisocyanate may be used in a small amount (for example, 20% by weight or less, preferably 10% by weight or less) which does not impair properties such as peel resistance from polyamide, thermoplasticity, thermal stability, high elongation and elasticity. Such a polymer as the polyurethane component may be mixed with the above-mentioned elastic polyurethane.

This elastic polyurethane is required to have an average molecular weight (X _MW ) of the constituent polyols of 1,000 to 3,000.
If the average molecular weight (X _MW ) is less than 1,000, the elastic polyurethane has insufficient tensile stress and elongation properties, and a conjugate fiber excellent in elongation recovery stress cannot be obtained. If it exceeds 3,000, the elastic polyurethane has good elongation properties, but the obtained composite fibers have insufficient stress properties.

In addition, the molecular weight of the higher molecular weight polyol (M
_W (A)) and the molecular weight of the lower molecular weight polyol (M
_W (B)) and the molecular weight ratio of _{(M W (A) / M} W (B)) is 1.3
It needs to be 6. If the molecular weight ratio is less than 1.3, the effect of the combined use of different molecular weights is insufficient, so the stress characteristics of the elastic polyurethane are insufficient, and the effect of improving the recovery stress characteristics of the obtained composite fiber is insufficient. It is. More preferably, it is 1.5 or more. Conversely, if it exceeds 6, although the stress characteristics of the elastic polyurethane are excellent, phase separation within the elastic polyurethane is apt to occur, and the polymer viscosity fluctuation at the time of melting is remarkably large, making it difficult to perform melt spinning. It is not suitable because it tends to form mottle on the composite fiber. Further, for these stable fibers, the number is preferably 5 or less.

The molecular weight of the polyol is adjusted by adjusting the molecular weight of the polyol to be subjected to the polymerization reaction of the polyurethane.
It can be any level. The molecular weight of the polyol can be adjusted to a desired level by adjusting the degree of polymerization in the polyol production step by a usual method.

Further, the molecular weight of the soft segment constituent polyol,
It can be determined by gel permeation chromatography (GPC) using a molecular weight calibration method based on polystyrene, using tetrahydrofuran as a solvent, and measuring with a type 244 gel permeation chromatograph (WATERS).

The average value (X _MW ) of the number average molecular weight of the constituent polyols of the elastic polyurethane is calculated by the following equation.

(Wherein, M _Wi is the number average molecular weight of each polyol, I r _i is. Represents the weight composition ratio of the polyol) to the polyurethane component of the composite fibers identified in claims 1, prior to melt spinning It is preferable to use an elastic polyurethane having a 100% tensile stress of 125 kgf / cm ² or more at the stage of the polyurethane component. By setting the 100% tensile stress of the elastic polyurethane before the melt spinning to 125 kgf / cm ² or more, the recovery stress characteristics of the conjugate fiber can be sufficiently improved.

As the polycarbonate-based polyol, 4,4 '
Aromatic polycarbonate from dioxydiphenyl-2,2'-propane (bisphenol A), and aliphatic polycarbonate obtained by reacting an aliphatic dihydric alcohol with phosgene. The molecular weight of these polyols is about 1,000 to 5,000, and even 20
It is preferably at least 00.

Examples of the polyether polyol include poly (oxyethylene) glycol, poly (oxypropylene) glycol, poly (tetramethylene) glycol, and the like. Examples of the polyester-based polyol include acids such as adipic acid, glutaric acid and sebacic acid, and ethylene glycol, 1,4-butylene glycol, 1,3- or 2,3-butanediol, and 2,5-hexanediol. Molecular weight obtained by condensation reaction from
A polyester of about 0 to 3,000 is exemplified.

Further, as a diisocyanate for obtaining an elastic polyurethane, diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate,
Examples include isophorone diisocyanate and lysine diisocyanate. Examples of the chain extender include low molecular weight diol, hydrazine, ethylenediamine, bis-β-hexanone and the like. -NCO terminal group and -O in polymerization raw material
The molar ratio with the H terminal group (-NCO / -OH) may be about 1.00 to 1.10.

These polymerization raw materials can be polymerized by an ordinary polyurethane polymerization method such as a one-shot method or a prepolymer method, or further mixed with a polymer or an additive to obtain an elastic polyurethane.

Furthermore, the hardness of the elastic polyurethane is generally preferably higher, and preferably has a Shore hardness A of at least 90 in order to achieve the object of the present invention. Further, it is practically difficult to make this hardness too high, and therefore, about 75 in Shore hardness D is the practical upper limit. The Shore hardness A is a value measured by the method A described in JIS K6301, and the Shore hardness D is a value measured by the method described in ASTM2240.

In order to suppress the viscosity variation during melt spinning when the hardness of the elastic polyurethane is increased, it is effective to control the degree of polymerization of the polyurethane to an appropriate range according to the polyurethane composition, and generally, 3500 to 35,000 poise It is preferable to have a melt viscosity of the order.

On the other hand, the polyamide component used in the present invention may be a melt-spinnable polyamide such as nylon 6, nylon 66, nylon 6,10, or a copolymerized polyamide thereof. In order to obtain a composite fiber with good physical properties such as abrasion,
It is preferable to use a polyamide having a melting point of 200 ° C. or higher. However, a polyamide having an excessively high melting point is not preferable for complex spinning with polyurethane, and it is practically preferable that the melting point is at most about 300 ° C. Among them, a polyamide having a melting point of 210 ° C. or more is preferable,
In particular, a polyamide substantially consisting of nylon 6 or nylon 66 is preferred. The degree of polymerization only needs to have a relative viscosity ηr of a degree used for clothing fibers, and for example, a sulfuric acid relative viscosity of about 2.0 to 2.8. The polyamide component may contain usual additives such as a heat-resistant agent, a light-resistant agent, and a matting agent.

The above-mentioned polyurethane and polyamide may be basically made into eccentric conjugate fibers by spinning in the same manner as conventional melt-spinning of polyamide and polyurethane. For example, after each polymer (composition) is supplied to a normal melt composite spinning machine and melted separately, composite spinning is performed using a composite spinneret heated to about 230 to 290 ° C., and a normal spinning method is performed. What is necessary is just to produce a latently crimpable conjugate fiber by crystallizing the polyamide component.

The composite structure may be any eccentric composite structure that provides a potential crimp that can exhibit a coiled crimp by crimp development treatment, and examples thereof include an eccentric core-sheath composite structure and a sand-by-side bonded composite structure. No. The composite ratio also depends on the composite structure, but is generally 80/20 to 2
It may be about 0/80. Further, it is preferable that the polymer occupying the outer peripheral surface of the fiber is a polyamide or that the ratio thereof is large.

Polyurethane obtained by melt composite spinning
The polyamide eccentric conjugate fiber is crimped by a usual method, and can exhibit elastic properties as a coiled crimped fiber.

[Action] In the elastic polyurethane, it is considered that the hard segment crystal part gives strength to the polymer and the soft segment amorphous part gives the polymer elongation. Therefore, it is effective to optimize the conditions such as the polymer composition ratio, the polyol and the chain extender component in order to give sufficiently high properties in both elongation and strength.

The molecular weight and type of the polyol constituting the soft segment affect the properties of the obtained elastic polyurethane. For example, in general, the lower the molecular weight of the polyamide, the higher the stress and the lower the elongation of the elastic polyurethane. On the contrary, the higher the molecular weight of the polyamide, the lower the stress and the higher the elastic polyurethane. Therefore, it is difficult to obtain an elastic polyurethane having high stress and elongation by simply adjusting the molecular weight of the constituent polyol to one level.

By increasing the molecular weight of the polycarbonate polyol unit, high elongation characteristics can be obtained.In addition, since the polycarbonate polyol has a higher stress level than other polyol units, the molecular weight is increased. Can obtain stress characteristics that are practically satisfactory, so that both the elongation characteristics and the stress characteristics can be satisfied. Furthermore, by lowering the molecular weight of the other polyol units, robust recovery properties can be provided.

As a result, an elastic polyurethane having excellent elongation properties, recovery properties and recovery stress properties can be obtained. Then, when this is made into a latently crimpable conjugate fiber eccentrically composited with a polyamide component, and this is crimped to produce a coiled crimped fiber, excellent elastic properties are exhibited.
For example, as compared with a conventional polyurethane / polyamide composite crimped fiber made of polyurethane, it has a higher elongation recovery stress, the recovery stress and the elongation stress of the obtained knitted fabric product are greatly increased, and the fit property is greatly improved.

[Examples]-Example 1 A 1: 1 (weight ratio) mixed polyol of polycarbonate and polycaprolactone was used, and 1,4-
Butylene glycol was polymerized by a normal one-shot method using diphenylmethane diisocyanate as a diisocyanate to obtain a polyurethane polymer.
After the obtained polymer was pulverized, it was melt-extruded with an extruder and pelletized.

In the above polymerization, -NCO terminal group and -O
The molar ratio to the H terminal group (-NCO / -OH) was 1.04. The polycarbonate and polycaprolactone used as the polymerization raw material polyols each have a molecular weight of 10
Those different from 00, 2000, and 3000 were used in combination as shown in Table 1.

Each of the obtained elastic polyurethanes had a Shore hardness A of 95. And its tensile stress (100%
Tensile stress and elongation were measured by conventional methods, and the results are shown in Table 1.

These elastic polyurethanes and 98% sulfuric acid polycapamide having a relative viscosity of 2.40 were separately melted at 230 ° C and 260 ° C, respectively, and supplied to a composite spinning machine. Spinning out composite to core-sheath shape,
It was cooled and lubricated by a usual method, and was wound at 600 m / min.
Then, it was stretched 4.0 times with a stretching machine to obtain a latently crimpable composite filament yarn of 18 denier and 2 filaments.

This composite filament yarn is knitted into a stocking knitted fabric by a usual method, heat-set with 110 ° C pressurized steam to produce a stocking product, and its elongation recovery stress characteristics are measured. The results are shown in Table 1.

 The measurement of the above physical properties was performed by the following methods.

Stocking crimping characteristics: TOM constant elongation type tensile tester
Using a model -100E (manufactured by Shinko Tsushin Kogyo Co., Ltd.), the length of the stocking sample when extended by applying a load of 2 kg was L1, the stocking sample was folded in two, and the tensile tester was used. Draw a hysteresis curve of stress strain that elongates to 75% of 2 and recovers immediately. From this hysteresis curve, the stress value (g) at the time of elongating 75% of L1 / 2
And the stress value (g) at the time of recovery to the length of 60% elongation of L1 / 2 from the curve at the time of recovery.
The values obtained in Table 1 were expressed as 75% elongation stress and 60% recovery stress, respectively. These values are indices indicating the fit of the stocking, and the higher the value, the better the fit. The fit is a relative evaluation result obtained by a wearing test, and is shown on the basis of ◎: extremely good, ：: good, Δ: slightly poor, and ×: poor.

As is clear from the results in Table 1, when the molecular weight ratio of the polyol is within the range specified in the present invention (Nos. A to C)
Has excellent stress characteristics and elongation characteristics, and can be made into a stocking product having excellent fitting properties, and also has excellent appearance, feeling, fit and durability when worn.

In contrast, when the molecular weight ratio of the polyol is small (N
oD to G) were poorly-fitting stocking products.

[Effect of the Invention] Since the polyurethane-polyamide conjugate fiber according to the present invention uses an elastic polyurethane obtained by combining polyols having different molecular weights under specific conditions as the polyurethane component,
Both the elongation and the stress of the polyurethane component are excellent, and as a result, the recovery stress characteristics of the coiled crimped fiber after the onset of crimping can be significantly improved, and therefore, a stretch knitted fabric product with even more improved fit. be able to.

The conjugate fiber according to the present invention can be widely used for textile products requiring high fit, but is particularly useful for stockings and stretchable tricot products.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-B 57-34370 (JP, B2) JP-B 55-22570 (JP, B2) JP-B 55-36725 (JP, B2) (58) Field (Int.Cl. ⁶ , DB name) D01F 8 / 12,8 / 16

Claims (3)

(57) [Claims] 1. An eccentric conjugate fiber comprising a polyurethane component and a polyamide component, wherein the elastic polyurethane constituting the polyurethane component contains, as a soft segment-forming polyol, at least two or more kinds of polyols having different number average molecular weights. A polyurethane characterized by containing a polycarbonate-based polyol as a polyol having a higher number average molecular weight among the polyols, and a number average molecular weight of the polyol simultaneously satisfying the following formulas (1) and (2). -Polyamide eccentric composite fiber. _{1000 ≦ MW ≦ 3000 ... (1} ) 1.3 ≦ M W (A) / M W (B) ≦ 6 ... (2) ( provided that, _MW is the average of the construction polyol number average molecular weight of the elastic polyurethane, M _W (A ) Indicates the number average molecular weight of the polycarbonate polyol having the higher number average molecular weight,
Further, the number average molecular weight of M _W (B) low of number average molecular weight towards the polyol represents respectively. ) 2. The eccentric polyurethane / polyamide fiber according to claim 1, wherein said elastic polyurethane has a Shore hardness A of 90 or more. 3. A polyurethane / polyamide eccentric conjugate fiber according to claim 1, wherein said polyurethane component has a 100% tensile stress of 125 kgf / cm ² or more when the polyurethane component and the polyamide component are melt-spun. A method for producing an eccentric polyurethane / polyamide fiber, comprising using an elastic polyurethane.