JPS6044406B2 - Method for producing colored polyurethane elastic yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing elastic polyurethane yarn, and more specifically to a method for producing colored polyurethane elastic yarn with excellent heat resistance by a melt spinning method.

Generally, a wet spinning method or a dry spinning method is used to produce polyurethane elastic yarns, and there are relatively few cases where a melt spinning method is used. This is because when melt-spinning a polyurethane elastomer, it is difficult to operate stably for a long time because the polyurethane elastomer generally has poor thermal stability when melted, and the polyurethane elastic yarn obtained by melt-spinning is not heat resistant. This is thought to be due to problems such as poor deformation and insufficient recovery from deformation at high temperatures. Several methods have been proposed to improve the thermal performance of urethane yarns obtained by melt spinning.

For example, Japanese Patent Publication No. 44-20247 proposes a method of adding a special polyfunctional compound during the synthesis of polyurethane.

Furthermore, Japanese Patent Publication No. 7426/1983 proposes a method of synthesizing polyurethane using a polyfunctional polyol and melt-spinning the obtained polymer. However, in the method of improving the heat resistance of polyurethane elastic yarn by imparting cross-linking to polyurethane using these polyfunctional compounds, the melting temperature of the polymer increases when sufficient cross-linking is imparted to improve the heat resistance. This creates the need to increase the

As a result, the polyurethane tends to thermally decompose, making spinning unstable, making it extremely difficult to carry out industrially. Further, as a method for producing polyurethane elastic yarn colored in an arbitrary color by a melt spinning method, there is a method in which a pigment is added during polymerization, but this method is not preferable because it contaminates the polymerization system with the pigment.

Similar problems arise when colored master chips are used. For this reason, in order to color urethane yarn, it is carried out to make a composite yarn through a process such as covering, and then dye it. In this case, the dyeability of the sheath thread and the urethane thread are generally different, and there are drawbacks such as the urethane thread is not colored or becomes too dark under the dyeing conditions for the sheath thread. As a countermeasure to these problems, methods have been proposed to improve dyeability, such as dyeing urethane threads with acid dyes, but these methods involve adding special compounds to the polymerization system and are not common.

An object of the present invention is to provide a polyurethane elastic yarn with excellent heat resistance, and another object is to provide a method for producing polyurethane elastic yarn of any color in a stable and industrially advantageous manner.

In the present invention, when melt-spinning a thermoplastic polyurethane elastomer, 5 to 50% of pigment is added to the molten polyurethane elastomer.
It is characterized in that the polyisocyanate compound contained therein is added, mixed, and then spun.

The thermoplastic polyurethane elastomer applied to the present invention is a known segmented polyurethane copolymer, and has a molecular weight of 500.
~6000 polyols such as dihydroxy polyether, dihydroxy polyester, dihydroxy polylactone, dihydroxy polyester amide, dihydroxy polycarbonate, block copolymers thereof, etc., and organic diisocyanates having a molecular weight of 500 or less, such as P,P''-diphenylmethane diisocyanate, tolylene diisocyanate. , hydrogenated P,P''-diphenylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,5-naphthylene diisocyanate, etc., and a chain extender having a molecular weight of 500 or less, such as water, hydrazine, diamine, glycol, etc. It is a polymer obtained by the reaction of Among these polymers, particularly good are those using polytetramethylene glycol, polycaprolactone, or polybutylene adipate as the polyol. Further, as the organic diisocyanate, P,P''-diphenylmethane diisocyanate is preferable.As the chain extender, glycol is preferable, and P,P''-bishydroxyethoxybenzene and 1,4-butanediol are particularly preferable. As described above, in the present invention, a polymer synthesized without using a branching agent or a crosslinking agent can be used as the thermoplastic polyurethane elastomer of the spinning raw material.

Therefore, the spinning temperature can be kept at a low level, and thermal deterioration of polyurethane can be suppressed. Of course,
Polymers containing branching or crosslinking to the extent that the spinning temperature is not excessively high can also be suitably used. The polyisocyanate compound used in the present invention is a compound having at least two isocyanate groups in the molecule, and is a compound obtained by reacting a diisocyanate compound with a polyhydric alcohol such as a polyol, glycol, or triol.

In the present invention, those containing 5 to 50% pigment are used. The amount of the pigment-containing polyisocyanate compound added is preferably 3 to 3 weight percent, particularly preferably 5 to 2 weight percent, based on the mixture of the polyisocyanate compound and thermoplastic polyurethane.

The amount added varies depending on the type of polyisocyanate compound used, but if the amount added is small, the desired improvement in the thermal performance of the urethane thread will be insufficient. Moreover, if the amount added is too large, non-uniform mixing or deterioration of yarn quality during spinning may easily occur, making spinning unstable, which is not preferable. The pigment is preferably a pigment that has heat resistance at the melting temperature of polyurethane and does not react with polyisocyanate compounds, such as titanium oxide, carbon black, zinc white,
Inorganic pigments such as barium sulfate, calcium carbonate, lithopone, cadmium yellow, yellow lead, titanium yellow, chromium permillion, amper, red iron oxide, cobalt blue, cobalt violet, chromium oxide green, ultramarine blue, etc.
Copper phthalocyanine blue, copper phthalocyanine green,
Organic pigments such as azo pigments and quinacridine pigments are used.

In particular, fine powder pigments with an average particle diameter of 10 μm or less are preferably used.

The pigment can be added to the polyurethane elastomer by using colored master chips, but it is preferable to add the pigment after it has been incorporated into the polyisocyanate compound in advance.

The method of incorporating a pigment into a polyisocyanate compound is as follows:
It is possible to add and disperse the pigment after synthesizing the polyisocyanate compound, but since polyisocyanate compounds are easily deteriorated by moisture in the air, it is preferable to disperse them before synthesizing the polyisocyanate compound. It is.

For example, a pigment is added to a polyol, sufficiently dispersed using a stirring device such as a homomixer, coarse particles are removed by filtration or sedimentation if necessary, and then reacted with an organic diisocyanate compound to synthesize a polyisocyanate compound. The content of the pigment is preferably 0.15 to 1%, particularly preferably 0.5%, based on the mixture of the thermoplastic polyurethane elastomer, the polyisocyanate compound, and the pigment.
~6% by weight.

If the content is too large, the fluidity of the polyisocyanate compound decreases, making handling difficult.

Moreover, if the content is small, coloring will be insufficient. The melt spinning of the present invention is preferably carried out using a spinning device equipped with a section for melt-extruding the thermoplastic polyurethane elastomer, a section for adding and mixing the polyisocyanate compound, and a spinning head. As such a spinning device, a known device used for adding a modifier during spinning can be used. Although it is possible to use a kneading device having a rotating part for adding and mixing the polyisocyanate compound to the molten polyurethane, it is more preferable to use a mixing device having a stationary kneading element. That's true.

A known mixing device having a static kneading element can be used. The shape and number of elements of the static kneading element vary depending on the conditions of use, but they are selected so that sufficient mixing of the polyurethane elastomer and polyisocyanate compound is completed before they are discharged from the spinneret. That is essential. An example of an embodiment of the present invention will be described below.

Pellets of thermoplastic polyurethane elastomer are fed from a hopper and heated and melted by an extruder. Melting temperature is 190~
A range of 2300C is preferred. On the other hand, the polyisocyanate compound containing the pigment was heated to 100°C in the supply tank.
Melt at the following temperature and defoam in advance. If the melting temperature is too high, it tends to cause deterioration of the polyisocyanate compound, so it is preferable that it be as low as possible within the melting range.
Temperatures between 0.degree. and C. are suitably used. The molten polyisocyanate compound is metered by a metering pump, passed through a filter if necessary, and added to the molten polyurethane at a meeting point provided at the tip of the extruder. The polyisocyanate compound and polyurethane are kneaded using a kneading device having a static kneading element. This mixture is metered by a metering pump and introduced into the spinning head. As the spinning head, a conventional synthetic fiber spinning device may be used, but it is preferable to design the spinning head in a shape that minimizes the retention area of the mixture as much as possible. If necessary, a layer of wire mesh, glass beads, etc. is provided in the spinning head. After foreign matter is removed by a machine, the mixture is discharged from the nozzle, cooled in air, coated with oil, and then rolled up. The winding speed is usually 300 to 1500 w1. /Mi
n is used. Urethane yarn wound onto a spinning bobbin may have poor strength immediately after spinning, but its strength improves while it is left at room temperature, and its recovery characteristics from elongation at high temperatures also improve. Further, by applying heat treatment by an appropriate method after spinning, improvement of yarn quality and thermal performance is promoted. The polyurethane elastic yarn colored in any color obtained by the method of the present invention can be used in combination with other fiber materials to manufacture foundations, socks, swimwear, clothing, and various other types of stretch clothing. It has a remarkable effect on eliminating the phenomenon of white peeling during stretching (the color of the entire fabric appears to change because the urethane thread appears on the surface of the fabric), which occurs due to the difference in color from other fiber materials. Ta.

The present invention will be explained below with reference to Examples.

Parts in the examples represent parts by weight unless otherwise specified.
The yarn quality (strength, elongation, 300% stress) of the urethane thread was measured using a constant speed extension type tensile tester with a sample length of 5 cm and a tensile speed of 10.
Measured at 00%/Min. The elongation recovery rate is the recovery rate after 100% elongation using a constant speed elongation type tensile tester, immediately after removing the load and leaving it for 5 minutes, and represents the elastic performance of the urethane yarn. The 130° C. heat setting rate is the setting rate when a 100% elongated sample is left in a thermostatic chamber at 13 Cf'C.

The smaller this value is, the better the heat resistance is. Example 1 850 parts of polytetramethylene glycol with a molecular weight of 850 was added to 80
’C, rutile-type titanium dioxide (Fuji Titanium T
R84O) 4(1) parts and silicone oil (as a dispersant)
Toray Silicone SH-194) 1 was added and stirred for 3 hours using a homomixer to disperse the mixture.

After removing moisture from this mixture under reduced pressure, 500 parts of P,P''-diphenylmethane diisocyanate was added and heated for 3 more times at 80'C with gentle stirring in a nitrogen stream to obtain a reaction mixture. A polyisocyanate compound (4) is used. On the other hand, polytetramethylene glycol with a molecular weight of 1000 is used as a soft segment, P,P''-diphenylmethane diisocyanate is used as a diisocyanate compound, and P,P''-bishydroxyethoxybenzene is used as a chain extender. Polymerized thermoplastic polyurethane chips were obtained. These polyurethane chips and polyisocyanate compound (4) were used as spinning raw materials, and spun using a spinning machine equipped with a kneading device having a polyisocyanate compound metering device and a static kneading element. A nozzle with a diameter of 1 mm was used as the spinneret, and the winding speed was 5007 mm.
Four filaments of 70 denier were spun as TL/Min. Table 1 shows the yarn quality of urethane yarns obtained by spinning with varying amounts of the polyisocyanate compound (4) added. From Table 1, if a polyisocyanate compound containing a pigment is not added, no colored yarn will be obtained and the heat resistance will be poor, but by adding a polyisocyanate compound and spinning, the heat resistance will improve and a white full dull yarn will be obtained. It turns out that is obtained.

When the amount of titanium oxide added when synthesizing the polyisocyanate compound of this example was 580y, the fluidity of the reaction mixture was significantly lost, making it extremely difficult to meter and feed it to the spinning system.

Example 2 A polyisocyanate compound (B) was synthesized using carbon black instead of titanium dioxide in Example 1, and a thermoplastic polyurethane polymerized from polyε-caprolactone diol, P,P''-diphenylmethane diisocyanate, and butane diol. It was supplied to the spinning system.

Table 2 shows the yarn quality after the obtained urethane yarn was heat treated at 100 DEG C. for 30 minutes. From Table 2, if a polyisocyanate compound containing a pigment is not added, no colored yarn will be obtained and the heat resistance will be poor, but by adding a polyisocyanate compound and spinning, the heat resistance will improve and colored polyurethane It can be seen that thread is obtained. When the urethane thread obtained in Example 2-3 was knitted into the waist area instead of the rubber thread for panty pants, good physical properties were obtained, and the rubber thread was particularly noticeable when stretched after dyeing black. There was a feature that there was no 3 Example 3 Polytetramethylene glycol with a molecular weight of 2000, P,
P″-bishydroxyethoxybenzene and P,P″
A polyurethane chip made of -diphenylmethane diisocyanate and containing 30% (by weight) polytetramethylene glycol was synthesized.

Pigments shown in Table 3 are added to this polyurethane chip,
The mixture was melt-mixed using an extruder to obtain master chips. This master chip and a chip to which no pigment was added were mixed at a ratio of 1:10 to obtain a spinning chip. On the other hand, 8 (4) parts of polytetramethylene glycol with a molecular weight of 850 and 500 parts of P,P''-diphenylmethane diisocyanate were heated at 80°C for 30 minutes.
After reacting for a minute, a viscous polyisocyanate compound was obtained. The isocyanate group content of this product was 6.20%, and the molecular weight calculated from this was 1355. Using the spinning tip and polyisocyanate compound thus obtained, spinning was carried out using an extruder equipped with a polyisocyanate compound supply device and a static kneading element.

0.2 gourd cut as a spinneret. A flat yarn of 140 denier was spun using a 0 m slit type nozzle at a winding speed of 5007 TL/Min. Table 3 shows the results of spinning with different types of master chips. The fabric was knitted into the fabric and dyed flesh-colored with an acid dye, resulting in a panty-taste fitting with good elasticity and no white spots.

Claims (1)

[Scope of Claims] 1. A method for producing colored polyurethane elastic yarn, which comprises adding a polyisocyanate compound and a pigment to the melted polyurethane elastic body, mixing and spinning the mixture when melt-spinning the thermoplastic polyurethane elastic body. . 2. The polyol forming the thermoplastic polyurethane elastomer is at least one selected from the group consisting of polytetramethylene glycol or polycaprolactone polyester, polybutylene adipate, polyhexamethylene adipate, and polycarbonate having a number average molecular weight of 500 to 6000. 2. The method of claim 1, wherein the polyol comprises: 3. The method according to claim 1, wherein the chain extender forming the thermoplastic polyurethane elastomer is a glycol or triol having a molecular weight of 500 or less. 4. The method according to claim 1, wherein the organic diisocyanate forming the thermoplastic polyurethane elastomer is P,P'-diphenylmethane diisocyanate. 5. The method according to claim 1, wherein the polyisocyanate compound has a molecular weight of 800 or more. 6. The method according to claim 1, wherein the polyisocyanate compound is a diisocyanate compound. 7 The diisocyanate compound has a molecular weight of 300 to 2500
Claim 6, which is an isocyanate-terminated compound obtained by adding P,P'-diphenylmethane diisocyanate to both ends of at least one polyol selected from the group consisting of polyether, polyester, polyester amide, and polycarbonate. Method. 8. The method according to claim 1, wherein the amount of the polyisocyanate compound added is 3 to 30% by weight based on the mixture of the thermoplastic polyurethane elastomer, the polyisocyanate compound, and the pigment. 9. The method according to claim 1, wherein the pigment is an inorganic or organic pigment with an average particle diameter of 10 μm or less. 10 The pigment content is 0 for the mixture of the thermoplastic polyurethane elastomer, the polyisocyanate compound, and the pigment.
．． A method according to claim 1, wherein the amount is 15 to 10% by weight. 11. The method according to claim 1, wherein the pigment is mixed in advance with the polyisocyanate compound. 12. The method according to claim 1, wherein the mixing is carried out in an apparatus equipped with a static kneading element.