Polyurethane Elastic Yarn and Manufacturing Method Thereof

Abstract

To provide a polyurethane elastic yarn that is superior in unwinding properties and adhesive properties in respect to a hot melt adhesive agent, and to provide a manufacturing method thereof. A polyurethane elastic yarn wherein the main structural component of the polyurethane is a polymer diol or diisocyanate; and includes a polymer that includes, as the main structural unit, a structural unit that uses an aromatic olefin and/or an aliphatic diolefin as a monomer, and is partially hydrogenated or completely hydrogenated.

Claims

1: A polyurethane elastic yarn including: a hydrocarbon resin (A) that has a structure wherein a polymer that includes, as the main structural units, structural units that use an aromatic olefin and/or an aliphatic diolefin as a monomer, is partially hydrogenated or completely hydrogenated; and a polyurethane.

2: A polyurethane elastic yarn as set forth in claim 1, wherein: the hydrocarbon resin (A) has a structure wherein the polymer that includes structural units that use an aromatic olefin as a monomer is partially hydrogenated or completely hydrogenated, and the aromatic olefin is indene and/or methyl styrene.

3: A polyurethane elastic yarn as set forth in claim 1, wherein: the hydrocarbon resin (A) has a structure wherein the polymer that includes structural units that use an aliphatic diolefin as a monomer is partially hydrogenated or completely hydrogenated, and the aliphatic diolefin is isoprene and/or an isomer thereof.

4: A polyurethane elastic yarn as set forth in claim 1, wherein: the thermal softening point of the hydrocarbon resin (A) is no less than 70° C. and no greater than 140° C.

5: A polyurethane elastic yarn as set forth in claim 1, wherein: the hydrocarbon resin (A) is included at no less than 0.1 mass % and no greater than 10 mass %.

6: A polyurethane elastic yarn as set forth in claim 1, wherein: the hydrocarbon resin (A) is dissolved at no less than 10 mass % at 20° C. in respect to a hydrocarbon oil (b), and is insoluble in DMAc and/or DMF.

7: A method for manufacturing a polyurethane elastic yarn wherein: after a hydrocarbon resin (a) that has a structure wherein a polymer that includes, as the main structural units, structural units that use an aromatic olefin and/or an aliphatic diolefin as a monomer is partially hydrogenated or completely hydrogenated is dissolved in a hydrocarbon oil (b), the hydrocarbon resin (a) is added so as to be in a range of no less than 0.1 mass % and no greater than 10 mass % in respect to a polyurethane solid content in a polyurethane spinning solution, and solution spun.

8: A method for manufacturing a polyurethane elastic yarn as set forth in claim 7, wherein: after the hydrocarbon resin (a) is dissolved at a concentration of no less than 5% in the hydrocarbon oil (b), it is added to a polyurethane spinning solution, and solution spun.

Description

EXAMPLES

[0106] While the present invention will be explained in more detail using examples, the present invention is not limited to these forms. The methods for evaluating the various types of characteristics in the present invention will be explained below first.

[0107] Tensile Strength and Elongation of the Polyurethane Elastic Yarn

[0108] An Instron model 4502 pull tester was used to measure the strength and elongation, at the moment of breaking, of samples of the polyurethane elastic yarn.

[0109] Specifically, elongation to 300%, with a pulling speed of 50 cm/min, of a sample yarn with a sample length of 5 cm (L1) was repeated five times. This length was then maintained for 30 seconds. On the sixth time, the sample yarn was stretched until breaking. The tension at the moment of breaking was defined as (G3), and the sample length at the moment of breaking was defined as (L3). The characteristics described above are given through the following formulas:

[00001]$\mathrm{Breaking}\mathrm{strength}=\left(G3\right)$$\mathrm{Breaking}\mathrm{elongation}=100\times \left\{\left(L3\right)-\left(L1\right)\right\}/\left(L1\right)$

[0110] Note that the pulling test was performed five times, and the mean was calculated.

Unwinding Performance of the Polyurethane Elastic Yarn

[0111] After a 4.5 kg wound yarn body of the polyurethane elastic yarn was stored for 14 days in a 35° C., 65% RH ambient, the wound yarn body was unwound to the position that is 1 cm from the winding cone, and the wound yarn body, after unwinding, was placed so that the surface thereof was in contact with a textured roller (a), and the polyurethane elastic yarn was fed out, at the roller surface speed of 30 m/min, while rotating the roller. The polyurethane elastic yarn that was fed out was caused to travel once around a textured roller (b) having the same diameter, placed at a location 100 cm away, where the surface speed of the roller (b) was varied gradually, to find the speed of the roller (b) wherein the polyurethane elastic yarn is fed out smoothly from the roller (a) without the polyurethane elastic yarn being lifted up on the wound yarn body, where the speed ratio (b)/(a) of the rollers was defined as the unwinding performance of the polyurethane elastic yarn. Smaller values for unwinding performance indicate better separation of the polyurethane elastic yarn.

[0112] Note that the unwinding performance test was performed using two wound yarn packages, and the mean thereof was calculated.

Hot Melt Adhesive Performance

[0113] A hot melt adhesive agent having, as the main component, a hydrogenated styrene-butadiene styrene copolymer, melted in a pot at 150° C. was coated, at stipulated proportions for individual polyurethane elastic yarns (0.03 g/m, 0.07 g/m) using a comb gun while eight lines of polyurethane elastic yarn were caused to move, in a single direction with uniform spacing therebetween, tensioned by a person prescribed draft (draft 3.0) over a nonwoven fabric made from polypropylene with a width of 15 cm, traveling at a speed of 130 m/min, after which another nonwoven fabric made from polypropylene was laid thereover from above, and contact bonded, and wound, to produce a stretchable sheet.

[0114] The stretchable sheet thus obtained was secured to a flat plate made of wood, and in a state wherein the nonwoven fabric was completely stretched, razor blade was used to cut, from above the stretchable sheet, a total of 16 locations, being 30 cm from the end on both ends of each of the eight polyurethane elastic yarns on the nonwoven fabric. This tension plate was stored at 40° C., 80% RH, and the contraction of the polyurethane elastic yarn that was secured by the hot melt adhesive agent onto the polypropylene nonwoven fabric, that is, the yarn length (L4) after slipping in, as the original length, and the length (L5), between the two cut portions, were measured at elapsed storage times of two hours and eight hours. Note that the measurements were carried out for a total of 24 elastic fibers, and the mean hot melt adhesive maintenance rates for the 24 fibers was calculated.

[00002]$\mathrm{Hot}\mathrm{melt}\mathrm{adhesive}\mathrm{maintenance}\mathrm{rate}\left(\%\right)=100\times \left(L4\right)/\left(L5\right)$

Preparation of Solution (A1)

[0115] A solution (A1) was prepared by dissolving 20 mass % of a hydrocarbon resin manufactured by Arakawa Chemical Company (“ARKON (registered trademark)” P-90, thermal softening point=90° C.) in mineral oil wherein the proportion of components having a carbon number of no less than 30 was 2%, for 100 seconds at 35° C., using a Redwood viscometer.

Preparation of Solution (A2)

[0116] A solution (A2) was prepared by dissolving 40 mass % of a hydrocarbon resin manufactured by JXTE Energy (“T-REZ (registered trademark)” RA100, thermal softening point=99° C.) in mineral oil wherein the proportion of components having a carbon number of no less than 30 was 1%, for 80 seconds at 35° C., using a Redwood viscometer.

Preparation of Solution (A3)

[0117] A solution (A3) was prepared by dissolving 40 mass % of a hydrocarbon resin manufactured by JXTE Energy (“T-REZ (registered trademark)” RA1115, thermal softening point =114° C.) in mineral oil wherein the proportion of components having a carbon number of no less than 30 was 1%, for 80 seconds at 35° C., using a Redwood viscometer.

Preparation of Solution (A4)

[0118] A solution (A4) was prepared by dissolving 20 mass % of a hydrocarbon resin manufactured by Arakawa Chemical Company (“ARKON (registered trademark)” M-135, thermal softening point =135° C.) in mineral oil wherein the proportion of components having a carbon number of no less than 30 was 2%, for 100 seconds at 35° C., using a Redwood viscometer.

TABLE-US-00001 TABLE 1 Hydrocarbon Resin (a) Hydrocarbon Oil (b) Softening Point: Softening Point: Softening Point: Softening Point: Viscosity: Viscosity: 90° C. 99° C. 115° C. 135° 100 sec 80 sec Arkon (R) P-90 T-REZ RA 100 T-REZ RC 115 Arkon (R) M-135 @35° C. @35° C. Solution (A1) 40 60 Solution (A2) 40 60 Solution (A3) 40 60 Solution (A4) 20 80

Example 1

[0119] MDI and PTMG with a number-average molecular weight of 1800 were loaded into a container so that the mole ratio was MDI/PTMG=1.58/1, and reacted at 90° C., and the reaction product obtained was dissolved in N,N-dimethylacetoamide (DMAc). Next a DMAc solution that includes ethylenediamine and diethylamine was added to the solution in which the aforementioned reaction product was dissolved, to prepare a polyurethane urea solution wherein the solid content in the polymer was 35 mass %.

[0120] Following this, a condensation polymer of p-cresol and divinylbenzene (“Metachlor (registered trademark)” 2390, manufactured by DuPont Corporation, as an oxidation inhibiting agent, and 2-[4,6-bis (2,4-dimethyl phenyl)-1,3,5-triazine-2-yl]-5-(octyloxy) phenol (“Cyasorb (registered trademark)” 1164, manufactured by Cytec Corporation), as an ultraviolet radiation absorbing agent, were mixed with a 3:2 mass ratio, to prepare the DMAc solution (concentration: 35 mass %), and this was used as the additive solution (35 mass %).

[0121] The polyurethane urea solution and the additive solution were mixed at a proportion of 98 mass %:2 mass %, to produce the polyurethane spinning solution (X1).

[0122] Solution (A1) was mixed so as to be 10 mass % in respect to the solid content of the polyurethane spinning solution (X1), to prepare a spinning solution (Y1). A polyurethane elastic yarn (580 decitex, 56 filament) (Z1) was manufactured through dry spinning this spinning solution (Y1) with a winding speed of 500 m/min, to produce a 4.5 kg wound yarn body.

Example 2

[0123] As the treating agent when winding the polyurethane elastic yarn, a treating agent (B1) of 25% polydimethyl siloxane, 73% mineral oil, and 2% St-Mg was prepared.

[0124] A 4.5 kg wound yarn body was produced in the same manner as in Example 1, aside from winding up while applying the treating agent (B1), at 1% dry mass, to the polyurethane elastic yarn during winding.

Examples 3-6, Reference Examples 1-4

[0125] 4.5 kg wound yarn bodies were produced from polyurethane elastic yarns in the same manner as in Example 1 or Example 2, with the exception of varying the types and/or inclusion proportions of the components as shown in Table 1.

Examples 7-8, and Reference Examples 5-6

[0126] 4.5 kg wound yarn bodies of polyethylene elastic yarns were produced similarly to the other examples and reference examples, except for changing the gauge to 310 decitex (32 filament) as shown in Table 1.

[0127] The results of the various evaluations on the yarns produced are shown in Table 1. The polyurethane elastic yarns of Examples 1 through 8 demonstrated adequate performance in all evaluations. On the other hand, in Reference Examples 1-6, the results were not satisfactory in both the unwinding performance and the hot melt adhesive performance.

Reference Example 7

[0128] Preparing Solution (A5)

[0129] While an attempt was made to dissolve 20 mass % of a hydrocarbon resin, manufactured by Arakawa Chemical Company (“ARKON (registered trademark)” P-90, thermal softening point: 135° C.) in mineral oil wherein the proportion of components with a carbon number of no less than 30 was 38%, for 250 seconds at 35° C. using a Redwood viscometer, complete dissolution was not possible, and thus this could not be added to the polyurethane solution.

TABLE-US-00002 TABLE 2 Polyurethane Elastic Yarn Hydrocarbon Resin (A) Hot Melt Adhesive Treatment Hydrocarbon Softening Amount Retention Rate Fracture Breaking Agent Resin Point added After After Releaseability Elongation Strength (dtex) (B1) Solution Type (° C.) (%) 2 hours 8 hours (—) (%) (cN) Embodiment 1 580 None (A1) Arkon P-90 90 5 92 87 2.0 521 340 Embodiment 2 580 1% (A1) Arkon P-90 90 5 93 88 1.7 525 342 Embodiment 3 580 None (A2) T-REZ RA100 99 8 93 87 2.2 501 322 Embodiment 4 580 1% (A2) T-REZ RA100 99 8 94 89 1.6 509 328 Embodiment 5 580 None (A3) T-REZ RC115 115 0.8 92 84 2.1 533 349 Embodiment 6 580 1% (A3) T-REZ RC115 115 0.8 92 83 1.9 530 344 Embodiment 7 310 None (A4) Arkon M-135 135 2 97 93 2.2 508 190 Embodiment 8 310 1% (A4) Arkon M-135 135 2 98 93 1.9 513 194 Reference 580 None — Not used — 0 84 61 2.8 522 335 Example 1 Reference 580 1% — Not used — 0 80 55 2.3 528 341 Example 2 Reference 580 None — Not used — 0 83 60 2.7 511 339 Example 3 Reference 580 1% — Not used — 0 82 51 2.3 506 333 Example 4 Reference 310 None — Not used — 0 97 90 3.0 511 192 Example 5 Reference 310 1% — Not used — 0 94 87 2.5 497 188 Example 6

INDUSTRIAL APPLICABILITY

[0130] The polyurethane elastic yarn according to the present invention had superior adhesive properties in respect to the hot melt adhesive agent, and can be used suitably in sanitary products such as disposable diapers, sanitary napkins, and the like, with superior comfort and fit. Moreover there is superior productivity, with no broken yarns in manufacturing sanitary products, such as disposable diapers, sanitary napkins, and the like, at high speeds, due to the superior unwinding properties.