WO2017086658A1 - Spandex with improved unwinding property and without occurrence of scum, and method for manufacturing same - Google Patents

Abstract

The present invention relates to spandex with improved unwinding properties and without the occurence of scum and a method for producing the same. More specifically, the present invention relates to spandex which is produced by adding polyethylene glycol to a polyurethane urea solution, which is a spinning solution, thereby effectively improving an irregular ballooning phenomenon and a tension spike phenomenon when unwinding spandex, having no adverse effect on other properties such as adhesion properties with hot melt and having unwinding properties without occurrence of scum, and a method for producing the same.

Description

Spandex without the improvement of nautical properties and scum generation, and manufacturing method thereof

The present invention relates to spandex without improving the unwinding property and the occurrence of scum, and to a method of manufacturing the same, more particularly, a polyethylene having a number average molecular weight of more than 3,000 to 11,000 in a polyurethaneurea solution, a spinning solution. By preparing spandex by injecting glycol, it is possible not only to effectively improve irregular ballooning and tension spike during dissolving spandex, but also to improve other physical properties such as adhesive properties with hot melt. The present invention relates to a spandex and a method for manufacturing the same, which have improved maritime properties and no scum, which can improve scum problems that may occur in rollers and guides during the diaper manufacturing process without a negative effect. .

Spandex maintains a high degree of rubber elasticity and is excellent in physical properties such as tensile stress and recoverability. Therefore, spandex is widely used in underwear, socks and sports clothing.

Such spandex is now being used as a functional fiber as its use is further expanded, and is being used for special purposes such as infants and elderly diapers or medical fibers.

Conventional medical spandex fiber has a higher interlaminar adhesion between fiber yarn and fiber yarn than general medical fiber, so it has poor maritime properties, resulting in many trimming and post-static processes in post-processing such as covering, canon and knitting work. There is a disadvantage that the tension of the non-uniform.

Therefore, in order to improve such a problem, it is common to introduce an anti-sticking agent into the polymer to improve its properties.

However, additives such as inorganic (Mg-st or Ca-st, Zn-st) compounds, which are conventionally used as anti-sticking agents, are not dissolved in the polymer solution and are dispersed, so that the material is evenly distributed on the dead surface. There is a problem that can not be, and when applied for the diaper manufacturing use has caused a problem in the maritime properties of the spandex.

In order to solve the problem of dissolvability of the spandex, KR 2011-0128884 A conventionally proposes an elastic fiber comprising polyurethane or polyurethaneurea and about 0.5% to 25% by weight of a soluble anti-sticking composition. . Here, cellulose (CAB) is used as an anti-sticking agent.

Furthermore, JP 2001-509847 A relates to spandex having low viscosity and a method for producing the same, and it is proposed to use an amide system such as ethylene bis-oleylamide / stearylamide containing nitrogen as an anti-sticking agent, and CN 001291079 C uses an antimicrobial agent such as zirconium phosphate, glass or zeolite as an anti-sticking agent for spantex.

However, although the anti-sticking agent applied to the existing spandex manufacturing to some extent prevents the adhesion between the fiber yarns, irregular ballooning and tension during the process of dissolving the spandex yarn during the diaper manufacturing process according to the addition of the inorganic material of the anti-sticking agent Tension spikes are not improving properly. In addition, even if the organic anti-sticking agent, the above problems are still not solved due to the drooping phenomenon, deterioration in adhesion with the hot melt and compatibility problems with the spandex polymer.

In addition, KR 2016-0080822 A, which was previously filed by the present applicant, did not affect the adhesion properties and physical properties of hot melt when polyethylene glycol having a molecular weight of 100 to 3,000 was used for the purpose of improving sealife properties. , Polyethylene glycol with molecular weight of 100-3,000 exists in unstable form in which liquid and solid such as semi-solid, cream or soft wax coexist at room temperature. There is a problem of burying and scum.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) KR 2011-0128884 A

(Patent Document 2) JP 2001-509847 A

(Patent Document 3) CN 001291079 C

(Patent Document 4) KR 2016-0080822 A

In order to solve the problems of the prior art as described above, the present invention efficiently improves irregular ballooning phenomenon and tension spike phenomenon appearing in the process of dissolving the spandex by using a new anti-sticking agent, diaper production without problems of other physical properties It is an object of the present invention to provide a spandex and a method of manufacturing the same, which does not generate scum in rollers and guides.

In order to achieve the object of the present invention as described above, the improvement in the dissolvability and the generation of scum according to the present invention is characterized in that it comprises a polyethylene glycol polymer represented by the following formula (1).

[Formula 1]

The polyethylene glycol polymer of Formula 1 has a number average molecular weight of more than 3,000 to less than 11,000.

In addition, the method for producing a spandex without improving the sea resolution and the occurrence of scum according to the present invention is a method for producing a spandex comprising a polyurethane prepolymer solution, polyurethane solution, polyurethane urea spinning solution, polyurethaneurea room Characterized in that it comprises a polyethylene glycol polymer represented by the following formula (1) as a slurry in the use solution in the form of a slurry.

 [Formula 1]

The polyethylene glycol polymer of Formula 1 has a number average molecular weight of more than 3,000 to less than 11,000.

The present invention is a polyethylene glycol polymer having a number average molecular weight of more than 3,000 to less than 11,000 in the form of a slurry in a spandex fiber spinning stock solution as an anti-sticking agent, conventionally added inorganic anti-sticking agents (Mg-st, Ca-st, Zn-st) In addition, it is possible to effectively improve irregular ballooning and tension spikes during spandex yarn disintegration during the diaper manufacturing process, and does not adversely affect the adhesive properties with hot melt necessary for diaper manufacturing.

In addition, by applying polyethylene glycol having a number average molecular weight of more than 3,000 to less than 11,000, problems exist in an unstable form in which a liquid and a solid such as semi-solid, cream or soft wax coexist at room temperature, and polyethylene glycol intermolecular attraction Due to the deterioration, it is possible to manufacture a spandex having improved maritime properties by eliminating the problem of smearing on rollers or guides in the diaper manufacturing process and appearing as a scum.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the installation for manufacturing the sample for creep evaluation in Experimental example 1 which concerns on this invention.

2 is an evaluation criteria graph showing OETO maritime evaluation in Experimental Example 3 according to the present invention.

Figure 3 is a photograph showing the structure diagram and scum occurrence position of the OETO maritime device in Experimental Example 4 according to the present invention.

4 (a) and 4 (b) are photographs showing when scum is generated in the OETO maritime apparatus in Experimental Example 4 according to the present invention.

5 (a) and 5 (b) are photographs showing when scum did not occur in the OETO maritime apparatus in Experimental Example 4 according to the present invention.

Hereinafter, described in more detail as an embodiment of the present invention as follows.

Spandex without disintegration improvement and scum generation of the present invention includes a polyethylene glycol polymer represented by the following Formula 1 as an anti-sticking agent.

[Formula 1]

The polyethylene glycol polymer of Formula 1 preferably has a number average molecular weight of more than 3,000 to less than 11,000.

The polyethylen glycol polymer is preferably included in 0.1 to 20% by weight based on the weight of the polyurethane urea solution solids.

Hereinafter, the embodiment of the method for producing a spandex without improving the sea resolution and scum generation according to the present invention will be described in more detail.

According to the present invention, a method for preparing a spandex without improving the disintegration property and generating a scum is a method for preparing a spandex, which comprises preparing a conventional polyurethane prepolymer solution, a polyurethane solution, and a polyurethaneurea spinning solution, wherein the spinning source is poly In the urethane urea solution, a polyethylene glycol polymer represented by the following formula (1) is used as an anti-sticking agent.

[Formula 1]

The polyethylene glycol polymer of Formula 1 has a number average molecular weight of more than 3,000 to 11,000.

According to a preferred embodiment of the present invention, a polyethylene glycol polymer having a number average molecular weight of more than 3,000 to less than 11,000 represented by Formula 1 above is added to a polyurethane urea solution used as a spinning stock solution in the preparation of spandex in the form of a slurry. Problems such as irregular ballooning and tension spike phenomenon do not occur.

If the number average molecular weight of the polyethylene glycol polymer is 3,000 or less, it exists in an unstable form in which a liquid and a solid such as semi-solid, cream or soft wax coexist at room temperature. Scum appears in the roller or guide due to the manufacturing process, and if the number average molecular weight exceeds 11,000, it does not dissolve uniformly in the solvent when preparing the slurry. You may not.

In addition, it is preferable that the polyethylene glycol polymer is added in the form of slurry in the spinning stock solution, since the polyurethane urea spinning is caused because it causes a change in the basic physical properties of the polymer when it is added during the polymerization of the polyurethane prepolymer solution to obtain the polyurethane solution. It is intended to express only the anti-sticking properties by adding the slurry in the form of a stock solution.

In this case, the slurry state may be prepared and used in a solution state dissolved in DMAc.

According to a preferred embodiment of the present invention, the polyethylene glycol polymer used as an anti-sticking agent may be added in an amount of 0.1 to 20% by weight based on the weight of the solid content of the polyurethaneurea spinning solution.

When less than 0.1% by weight can not be expected to prevent inter-stick adhesion due to an increase in seaweed tension, when exceeding 20% by weight there is a problem in the adhesiveness with the hot melt is undesirable.

The present invention is a spandex having a new maritime properties prepared as described above, is very suitable for application as a medical or hygine spandex.

In the case of manufacturing the spandex by the method according to the present invention, not only the adhesive property is excellent but also the sea tension is uniform, thus preventing irregular ballooning phenomenon and improving the tension spike phenomenon and preventing the occurrence of scum.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example

Example 1

601.1 g of diphenylmethane-4,4′-diisocyanate and 2664.5 g of polytetramethylene ether glycol (molecular weight 1,800) are reacted with stirring at 90 ° C. for 95 minutes in a nitrogen gas stream, and a polyurethane prepolymer having an isocyanate at both terminals Was prepared.

After cooling the prepolymer to room temperature, 4,811 g of dimethylacetamide was added and dissolved to obtain a polyurethane prepolymer solution.

Subsequently, 43.3 g of ethylenediamine, 1,2-propyldiamine, and 13.4 g of diethylamine were dissolved in 829 g of dimethylacetamide and added to the prepolymer solution at 9 ° C. or lower to obtain a polyurethane solution. 1% by weight of antioxidant triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate as an additive to the solid content of the polymer, and 1% by weight titanium dioxide as a light-resistant agent % Was added and the spinning stock solution was obtained. The spinning stock solution was prepared using 2 wt% of polyethylene glycol (number average molecular weight 4,000) as an anti-sticking agent in the form of a slurry in the spinning stock solution.

In a dry spinning process, the spinning temperature was set at 260 ° C. or higher and the winding speed was wound at 500 m / min.

Example 2

Spandex fibers were prepared in the same manner as in Example 1, except that 5 wt% of a polyethylene glycol polymer (number average molecular weight 4,000) as an anti-sticking agent was added to the spinning dope.

Example 3

Spandex fibers were prepared in the same manner as in Example 1, except that 10 wt% of a polyethylene glycol polymer (number average molecular weight 4,000) as an anti-sticking agent was added to the spinning dope.

Example 4

Spandex fibers were prepared in the same manner as in Example 1, except that 20 wt% of a polyethylene glycol polymer (number average molecular weight 4,000) as an anti-sticking agent was added to the spinning dope.

Example 5

Spandex fibers were prepared in the same manner as in Example 1, except that 2 wt% of a polyethylene glycol polymer (number average molecular weight 3,500) as an anti-sticking agent was added to the spinning dope.

Example 6

Spandex fibers were prepared in the same manner as in Example 1, except that 2 wt% of a polyethylene glycol polymer (number average molecular weight 10,000) as an anti-sticking agent was added to the spinning dope.

Comparative example

Comparative Example 1

Spandex fibers were prepared in the same manner as in Example 1, except that 25 wt% of a polyethylene glycol polymer (number average molecular weight 4,000) as an anti-sticking agent was added to the spinning dope.

Comparative Example 2

Spandex fibers were prepared in the same manner as in Example 1, except that 2 wt% of a polyethylene glycol polymer (number average molecular weight 2,500) as an anti-sticking agent was added to the spinning stock solution.

Comparative Example 3

Spandex fibers were prepared in the same manner as in Example 1, except that 2 wt% of a polyethylene glycol polymer (number average molecular weight 2,800) as an anti-sticking agent was added to the spinning stock solution.

Comparative Example 4

Spandex fibers were prepared in the same manner as in Example 1, except that 2 wt% of a polyethylene glycol polymer (number average molecular weight 12,000) as an anti-sticking agent was added to the spinning dope.

Comparative Example 5

Spandex fibers were prepared in the same manner as in Example 1, except that 1% by weight of magnesium stearate was added instead of 2% by weight of the polyethylene glycol polymer (number average molecular weight 4,000) as an anti-sticking agent in the spinning solution.

Comparative Example 6

Spandex fibers were prepared in the same manner as in Example 1, except that 0.5 wt% of the silicone emulsion in the spinning stock was added without adding the anti-sticking additive in the spinning stock.

Comparative Example 7

Spandex fibers were prepared in the same manner as in Example 1, except that 0.5 wt% of the silicone emulsion was applied to the solids of the yarn without adding an anti-tack additive in the spinning stock solution.

Comparative Example 8

Spandex fibers were prepared in the same manner as in Example 1, except that the anti-tack agent was not added to the spinning dope.

Experimental Example

Experimental Example 1

In order to evaluate the physical properties of the spandex fibers prepared in Examples and Comparative Examples to evaluate the creep properties (Creep) property of the adhesive properties as follows.

To this end, laminates were prepared using nonwoven fabric and spandex fibers.

In this case, a manufacturing facility uses a pilot coater of Nordson, and the method is as follows. (See Figure 1)

(1) Nonwoven fabrics 1 and 2 are fed and spandex yarns are fed side by side in the center.

(2) The elongation at the time of supplying spandex yarn is 250%, and the hot melt adhesive of Henkel Co., Ltd. is supplied by spiral spray method and Nip roller is used. Squeeze through and bond with nonwoven fabric. At this time, the amount of glue (Glue) is 60 mg / m.

(3) The production speed of the sample is 100 m / min.

The creep evaluation is carried out by the following procedure by the evaluation method of Japanese U company using the manufactured laminate.

(1) The laminate part is stretched to the maximum and fixed to a plastic plate 30 cm wide and 50 cm long.

(2) Mark both left and right 100 mm (total 200 mm) parts with the oil pen on the center.

(3) Cut the marked part with a sharp knife and measure the length without spandex. The creep property (%), which is an adhesive property, was calculated by the following equation.

The adhesion of the spandex fibers prepared in Examples 1 to 6 and Comparative Examples 1 to 8 was evaluated as described above, and is shown in Table 1 below.

	Example						Comparative example
Item	One	2	3	4	5	6	One	2	3	4	5	6	7	8
Adhesive property (%)	78.5	76.1	75.9	74.9	78.3	80.5	63.4	70.1	69.8	80.9	77.3	56.3	54.3	81.5

The results in Table 1 are obtained using the pilot coater of FIG. 1, and may be slightly different from the results during the diaper manufacturing process.

The pilot coater is slower than the actual diaper manufacturing process, and the adhesive method was also evaluated using a specific spray among various methods of the diaper manufacturing process.

Referring to Table 1, 2 to 20% by weight of the polyethylene glycol polymer having a number average molecular weight of 4,000 (Examples 1 to 4) and 2% by weight of the polyethylene glycol polymer having a number average molecular weight of 3,500 and 10,000 were added thereto. In the case (Examples 5 to 6), excellent adhesion properties are shown in comparison with Comparative Example 1 in which 25 wt% of polyethylene glycol polymer is added and Comparative Examples 6 and 7 in which silicone emulsion is applied without adding an anti-sticking agent. Could confirm that.

However, when the silicone emulsion is not applied as in Comparative Example 8, the creep is not different, and when polyethylene glycol having a molecular weight of 2,500 or 2,800 is added (Comparative Examples 2 to 3), it is confirmed that the adhesion characteristics of the low level are fine. Could.

Experimental Example 2

In order to determine the degree of uniformity of the maritime properties in addition to the adhesive strength for the spandex fibers prepared in the above Examples and Comparative Examples was evaluated as follows.

The maritime characteristic evaluation method is evaluated by installing a guide to fix the yarn at a distance of 30 cm from the fixed bobbin holder, and installing a sensor for measuring tension and a winding device with adjustable speed.

The tension measuring apparatus used for this evaluation apparatus is measured using the electronic tension meter of ROTHSCHILD. Maximum, minimum, average, and deviation values were measured and the results are shown in Table 2 below.

In this evaluation result, the difference between the maximum value and the minimum value and the average value are assured, and the lower the deviation value, the better the degree of uniformity of the maritime characteristics.

	Example						Comparative example
Item	One	2	3	4	5	6	One	2	3	4	5	6	7	8
Max. (G)	2.58	2.14	2.31	2.09	2.44	2.69	0.69	2.89	2.29	4.45	8.15	2.34	2.89	60.88
Min. (G)	0.31	0.22	0.33	0.20	0.39	0.41	0.02	0.25	0.22	1.73	0.47	0.25	0.34	10.54
Ave. (g)	0.71	0.64	0.72	0.62	0.76	0.69	0.12	0.70	0.72	2.73	1.07	0.69	0.73	29.25
Dev. (G)	0.56	0.41	0.52	0.40	0.46	0.49	0.02	0.45	0.42	1.67	0.94	0.44	0.47	8.19

Referring to Table 2, even when a polyethylene glycol polymer having a molecular weight of 4,000 (Examples 1 to 4) and a polyethylene glycol polymer having molecular weights of 3,500 and 10,000 (Examples 5 and 6) were applied to maritime tension. The level was similar to that in the case where the silicone emulsion was added to the spinning stock solution or applied to the yarn (Comparative Examples 6 and 7) without adding the anti-sticking agent of the present invention.

And when compared with the case where an inorganic anti-sticking agent was used (comparative example 5), the maximum value showed the low level.

Moreover, it turned out that it shows the outstanding maritime tension value compared with the case where no additive is added (comparative example 8).

However, when 25% by weight of a polyethylene glycol polymer having a molecular weight of 4,000 was added (Comparative Example 1), there was a problem in that the adhesive strength between yarns was too low because the sea tension was too low.

Experimental Example 3

Over-end-take-off (OETO) dissolution evaluation was performed on the spandex fibers prepared according to the above Examples and Comparative Examples.

This OETO maritime assessment was conducted in the following way.

When the Spandex fiber winding body is dismantled by OETO method, the following three types of sea sand are generated according to the magnitude of the force between the centrifugal force applied to the yarn and the adhesive force formed between the yarn and the yarn.

(A) Centrifugal force> Cohesion between yarns: irregular ballooning

(B) Centrifugal force 점착 cohesion between yarn: yarn without irregular ballooning or extremely weak

(C) Centrifugal force <cohesion between yarn: yarn incapable of trimming

For this nautical evaluation, the reference numeral in FIG. 2 means the following state.

Reference numeral 1 denotes a fixed guide: the seal is moved by the OETO method and moves straight from this point.

Reference numeral 2 is the firing point of the winding body: the point where the thread is first dismissed from the winding body under tension.

Reference numeral 3 denotes an angle formed by a line connecting a fixed guide and a winding body center and a sea thread when in an ideal sea form.

Reference numeral 4 denotes an angle corresponding to 1/2 of the reference numeral 3 outside the ideal solution angle.

Reference numeral 5 denotes a type 1 nautical morphology: an ideal nautical state in which the yarn is linearly dismantled along the angle of reference numeral 3.

Reference numeral 6 denotes a type 2 nautical morphology: the yarn follows the trajectory formed by the angle of reference 3, but with slight shaking.

Reference numeral 7 indicates a level 3 nautical form: the fact that a weak ballooning has occurred due to the fact that the track deviates from the trajectory of the reference number 3, but the trajectory of the reference number 4 does not deviate, indicates that there is no possibility of connecting to the thread.

Reference No. 8 shows a grade 4 maritime form: the balloon balloon is larger, leaving the trajectory of reference No. 4, and more likely to be connected to the thread according to the surrounding situation.

The results of the OETO maritime evaluation as described above are shown in Table 3 below.

division

Example

Comparative example

One

2

3

4

5

6

One

2

3

4

5

6

7

8

Maritime Class

1 ~ 2 grade

1 ~ 2 grade

1 ~ 2 grade

1 ~ 2 grade

1 ~ 2 grade

1 ~ 2 grade

3 ~ 4 grade

2-3 grade

2-3 grade

3 ~ 4 grade

3 ~ 4 grade

1 ~ 2 grade

1 ~ 2 grade

Maritime impossibility

Looking at the results of Table 3, it was confirmed that the Example according to the present invention exhibits excellent maritime characteristics compared to Comparative Examples (1 to 5, 8). However, when 0.5 wt% of the silicone emulsion in the spinning stock solutions of Comparative Examples 6 and 7 were applied or 0.5 wt% of the solids of the yarn, it was judged that there was no problem in the OETO maritime characteristics.

Experimental Example 4

The scum generation phenomenon was evaluated using an OETO (Over-end-take-off) dissolving facility for the spandex fibers prepared according to the Examples and Comparative Examples.

The OETO maritime system is composed of the tension control roller and sensor part of BTSR, and the frame, roller and guide device manufactured by Hyosung Co., Ltd.

Evaluation of scum occurrence using this facility was carried out as follows.

The spandex fiber winding body is dismantled using the OETO method, and the occurrence of scum on the tension control roller surface and the primary and secondary guides is evaluated.

In FIG. 2, reference numeral 1 denotes a roller for controlling the supply tension of spandex yarn during OETO maritime, reference numeral 2 denotes a first guide to be passed first, and reference numeral 3 denotes a second guide to be passed second.

The sea speed was 250 m / min, the sea time was 6 hours, and the tension was 40 g. The scum occurrence evaluation results are shown in Table 4.

Table 1 (1) is the tension control roller surface, (2) is the primary guide, (3) is the secondary guide, when scum occurs as shown in Fig. 4 (○), when scum does not occur as shown in FIG. It is written as (X).

Classification of scum occurrence

(○): When the yield of scum generated on the roller and the guide is 0.01 g or more as shown in Fig. 4, the value is recorded and denoted by ○.

(X): When the yield of scum generating minutes on a roller and a guide is 0.01 g or less like FIG. 5, it marks with x.

division

Example

Comparative example

One

2

3

4

5

6

One

2

3

4

5

6

7

8

(One)

X

X

X

X

X

X

O (0.34 g)

O (0.45 g)

O (0.29 g)

X

X

X

X

X

(2)

X

X

X

X

X

X

O (0.32 g)

O (0.41 g)

O (0.22 g)

X

X

X

X

X

(3)

X

X

X

X

X

X

O (0.28 g)

O (0.39 g)

O (0.24 g)

X

X

X

X

X

Looking at the results of Table 4, in the case of the Example according to the present invention it was confirmed that scum does not occur compared to Comparative Examples 1 and 2-3. By deferring Experimental Examples 1 and 2, it can be confirmed that creep property, sea tension, OETO sea property, and scum generation problems are improved.

Claims (6)

1. Spandex without the improvement of nautical properties and generation of scum characterized in that it comprises a polyethylene glycol polymer represented by the formula (1).

   [Formula 1]

   

   The polyethylene glycol polymer of Formula 1 has a number average molecular weight of more than 3,000 to less than 11,000.
2. The method of claim 1,

   Polyethylene glycol polymer is characterized in that it comprises 0.1 to 20% by weight based on the weight of the polyurethaneurea spinning solution solids, characterized in that the Spandex without scum improvement.
3. The method of claim 1,

   The spandex is a hygienic (hygine) or medical, characterized in that the improvement of the maritime properties and the occurrence of scum spandex.
4. In the method for producing a spandex comprising preparing a polyurethane prepolymer solution, polyurethane solution, polyurethane urea spinning solution,

   Method for producing a spandex without the improvement of nautical properties, characterized in that it comprises a polyethylene glycol polymer represented by the following formula (1) as a slurry in the polyurethane urea spinning solution in the form of a slurry.

   [Formula 1]

   

   The polyethylene glycol polymer of Formula 1 has a number average molecular weight of more than 3,000 to less than 11,000.
5. The method of claim 4, wherein

   Polyethyleneglycol polymer is a method for producing a spandex without improving nautical properties and scum characterized in that it comprises 0.1 to 20% by weight based on the weight of the polyurethane urea spinning solution solids.
6. The method of claim 4, wherein

   The slurry is prepared by using a solution dissolved in dimethylacetamide (DMAc; Dimethylacetamide), characterized in that to improve the dissolution properties and the production of spandex without scum.

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