JPS5844764B2 - Manufacturing method of polyurethane elastic yarn - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing polyurethane elastic yarn.

When compared with the dry spinning method and wet spinning method, which are commonly used for spinning polyurethane elastic yarns, the melt spinning method has the following advantages:
It has advantages such as no need for a solvent and a high spinning speed.

However, polyurethane elastomer generally has poor melt stability, making it extremely difficult to melt-spun, and even if melt-spinning is carried out, the resulting polyurethane elastic yarn has a relatively low softening point, making it difficult to deform at high temperatures. It has the disadvantage that recovery is insufficient.

Several methods have been proposed to improve the thermal performance of polyurethane elastic yarns obtained by melt spinning.

■ A method of using a chain extender with a high melting point to increase the softening point of the heart segment (for example, Japanese Patent Publication No. 43-26
Publication No. 317).

■ A method of imparting crosslinks using a polyfunctional chain extender (for example, Japanese Patent Publication No. 44-20247) C■ A method of imparting crosslinks using a polyfunctional polyol (for example, Japanese Patent Publication No. 43-7426) C■ From a polymerization system A method in which the polymerization or crosslinking reaction is completed after directly spinning the fiber into a filament (
For example, Japanese Patent Publication No. 43-22340).

■ After spinning the polyurethane elastic yarn and heat-treating it, it is treated with a cross-linking agent to provide cross-linking (for example, Japanese Patent Publication No. 42-2
(No. 3971, No. 47-13789) These methods use a special chain extender, and all of these methods attempt to branch or crosslink polyurethane, and none of them have been found to be effective. However, if we attempt to provide sufficient crosslinking to improve heat resistance, the stability of spinning may become poor, or a reaction may need to be carried out in a post-treatment process of the filament. At present, no industrially advantageous method for producing polyurethane elastic threads with excellent heat resistance has been established.

An object of the present invention is to provide a polyurethane elastic yarn with excellent recovery characteristics at high temperatures.

Another object of the present invention is to provide a method for industrially easily and inexpensively producing polyurethane elastic yarns having excellent melt spinnability and excellent recovery characteristics at high temperatures.

The method of the present invention uses an organic diisocyanate, a molecular weight of 700 to
3,000 polyester having hydroxyl groups at both ends, an aromatic diol, and an organic compound having at least 3 hydroxyl groups in one molecule, and 1. OO~1.10 and the polyester is 65~75
After uniformly mixing the weight-mixed polyurethane raw materials in a reactor equipped with a stirring mechanism and a heating mechanism, the mixture was heated to 60°C to 120°C.
The polyurethane elasticity is obtained by reacting at a temperature of ℃, the contents are taken out from the reactor after turning into powder, the powdered reactant is melt-extruded to form chips, and the resulting chips are then melt-spun. It is characterized in that the yarn is heat treated at 100 to 150°C under a constant length.

Examples of the organic diisocyanate compound used in the present invention include 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate-1-14,4'-dicyclohexylmethane diisocyanate , toluylene diisocyanate, hexamethylene diisocyanate, P-phenylene diisocyanate, xylylene diisocyanate, m-phenylene diisocyanate, 4,4'-isopropylidene-dicyclohexyl isocyanate, etc., and two or more of these may be used as a mixture. 4,4'-diphenylmethane diisocyanate is particularly good.

The polyester used in the present invention is a polyester having hydroxyl groups at both ends of the molecule, which is normally used in the synthesis of polyurethane. Polyesters obtained by polycondensation of dibasic acids such as adipic acid, succinic acid, sepatic acid, terephthalic acid, and inphthalic acid, or polyesters obtained by ring-opening polymerization of lactones, such as polyε-caprolactone and polyβ - Propiolactone etc., but polyethylene adipate is preferred.

The polyester can be mixed with a polyether commonly used in the synthesis of polyurethane in an amount of 20% (by weight) or less, but if the amount of polyether exceeds this amount, the heat resistance of the resulting polyurethane elastic yarn will decrease. It is not preferable because it is inferior in quality.

The polyester applied to the present invention has a molecular weight of 700 to 30
00, preferably 750-2500.

If the molecular weight is less than 700, the Young's modulus of the resulting polyurethane thread will be too high, and if it is larger than 3000, the resulting polyurethane thread will be too soft, and in either case, the object of the present invention cannot be achieved.

The polyester is used in an amount of 60 to 75 weight φ, preferably 65 to 73 weight φ, based on the polyurethane raw material.

The aromatic diol applied to the present invention is used as a so-called chain extender and usually has a molecular weight of 500 or less, and in particular, P-phenylenedi-β-oxyethyl ether,
Bishydroxyethylbenzene is preferred.

When an aliphatic diol is used as a chain extender, the product does not turn into powder in the reactor and is sticky, making it difficult to stir and take out. It is insufficient.

The organic compound having at least three hydroxyl groups in one molecule used in the present invention acts as a crosslinking agent, such as glycerin, trimethylolpropane, 1,3.6-hexandriol, 1,3 , 7-heptanetriol, 3heptane-1,2,6,7-tetrol, pentaerythritol, and glycerin.

Low polymerization degree polyethylene glycol, polypropylene glycol, or copolymers thereof using sorbitol or the like as an initiator may also be used.

Further, as the organic compound, one having a molecular weight of 500 or less is usually used, and trimethylolpropane is particularly preferred.

Therefore, in the present invention, it is important that the organic compound (crosslinking agent) having at least three hydroxyl groups per molecular weight and the aromatic diol be used in a ratio that satisfies the following formula.

This value is defined as the degree of crosslinking (DC).

If the degree of crosslinking (DC) is less than 0.02, the crosslinking density will be insufficient.

The heat resistance of 22 urethane yarn is poor, while the degree of crosslinking (DC)
When exceeds 0.07, the melt viscosity becomes significantly high, so it is necessary to increase the spinning temperature, thermal decomposition is likely to occur during spinning, and it becomes difficult to perform stable melt spinning.

In the present invention, the amount of organic diisocyanate in the reaction mixture must satisfy the following formula.

If this value is less than 1.00, the polymerization of polyurethane will not proceed sufficiently and only polyurethane threads with poor physical properties will be obtained.

Moreover, when this value is larger than 1.10, a heterogeneous reaction tends to occur in the polymerization machine, and in either case, the object of the present invention cannot be achieved.

The preferred range of the value of R is 1.02 to 1.07.

The polymerization reaction in the present invention is carried out in a reactor equipped with a stirring mechanism and a heating mechanism, but a reactor with a particularly strong stirring mechanism is preferable. Examples of such a reactor include a kneader with a warner set, There are kneaders with a set of screws, and kneaders with a set of warners are particularly suitable.

In the present invention, the polyurethane raw materials are reacted after being uniformly mixed in the above-mentioned reactor, and the reaction temperature is usually 60 to 150°C.
, preferably 80 to 120°C.

The polyurethane raw materials may be added separately into the reactor;
Alternatively, after producing the isocyanate group-terminated prepolymer, the remaining chain extender and crosslinking agent may be added.

The reaction time varies depending on the raw material composition, reaction temperature, etc., but is usually 1.
It is about 0-180 minutes.

As the reaction progresses, the reaction system changes from a liquid state to a paste state, and further from a solid state to a powder state.

When the reaction product becomes a powder, it is taken out of the system, melted and extruded using, for example, an extruder, which is used in the production of ordinary synthetic fiber raw material chips, and then cut into chips.

In this case, it may be extruded into a sheet and then cut to form chips.

Melt extrusion is usually carried out at a temperature below 230°C.

In the method of the present invention, by employing the polymer composition, reactor, and reaction temperature as described above, the reactant can be easily converted into a powdery polymer in the reactor.

The polyurethane produced in this way is chipped by a melting method, and when melt-spinning is performed, there is no significant increase in the spinning filtration pressure, there is no tendency to cause knotted yarn, and uniform urethane yarn can be obtained.

The powdered polymer taken out from the reactor is cured at a temperature of 80 to 120°C, if necessary, and made into chips by a melting method.

When making chips, light stabilizers, antioxidants,
A lubricant etc. can be added.

As the light stabilizer, benzotriazole compounds such as 2(2', hydroxymeth, 5' ditertiary amyl phenyl) benzotriazole (trade name: Chiga, Geigy Co., Ltd., Tinupin 328) are suitable.

In addition, as antioxidants, sterically hindered phenol compounds such as tetrasky (methylene-3,5-ditertiary-butyl-4-hydroxyhydrocinnamate) are used.
Methane (product name Ciba Geigy Irganox 10)
10) etc. are suitable.

As the lubricant, amide wax such as N,N' ethylenebisoleylamide, etc. is suitable for preventing urethane-based sticking.

If such a lubricant is added to the polymerization reactor, it has the effect of reducing contamination of the reactor, and it can also be added before polymerization.

Melt spinning is performed using the polyurethane chips obtained in this way, and a spinning machine used for ordinary synthetic fiber spinning can be used for melt spinning, and the spinning speed is 400 to 1100.
m/'l1unffi is suitable.

In addition, the spinning temperature is usually 230°C or lower, and 200 to 225°C.
is preferred.

It is preferable to apply an oil to the spun urethane thread to prevent sticking before winding it up.

As the oil agent, an aqueous solution of polysiloxane modified with alkylene oxide is particularly suitable.

The heat treatment of the polyurethane elastic yarn in the present invention is carried out with a constant length.

The constant length in the present invention means a substantially constant length, and includes expansion or contraction of 9 times or less.

When stretched, the elongation of the resulting urethane thread decreases, and when it is shrunk, the elongation becomes too high, which is not preferable.

The temperature of the heat treatment is 100 to 150°C, preferably 1
The temperature is 10-140°C.

If the heat treatment temperature is lower than 100°C, the heat resistance of the urethane thread will be insufficient, and if it exceeds 150°C, the urethane thread will deteriorate and cause sticking, both of which are not preferred.

The time for performing the heat treatment of the present invention is usually 10 minutes or more, particularly preferably 30 minutes or more.

The heat treatment of the present invention can be carried out by any method within the range that satisfies the above conditions, but for example, it can be suitably carried out by leaving the urethane yarn wound into a bobbin shape in a hot air heating tank. I can do it.

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

All parts in the examples are by weight unless otherwise specified.

Example 1 P-
9 parts of phenylene-di-β-oxyethyl ether and 0.1 part of trimethylolpropane were added and mixed, and 100'
After heating and dissolving at C, dehydration and drying treatment was performed at this temperature for 1 hour under the conditions of 3-7 mmH&.

The mixture thus dehydrated and dried was injected into a Nigu under a N2 stream, stirred, and the liquid temperature of the mixture reached 8.
When the temperature became constant at 5°C, 20.9 parts of 4,4'-diphenylmethane diisocyanate was added.
The contents became a powdery solid in about 20 minutes.

The composition in this case corresponds to R=1.02 and DC=2.4.

The powdered product thus obtained was heated for 1 hour under a N2 stream.
After curing at a temperature of 00°C for 24 hours, melt extrusion was performed using a screw extruder at 210°C for a residence time of 30 seconds to form chips.

Further, this chip was melt-spun at a temperature of 214° C. using a spinning machine having a nozzle of 1 mmφ at the tip, and the discharged filament was wound up at a speed of 600 ml/$71.

11 with this polyurethane elastic thread wound up on the bobbin.
Dry heat treatment was performed at 0°C for 1 hour.

Table 1 shows the performance of the polyurethane elastic yarn before and after heat treatment.

The elastic recovery rate is a value obtained when a 100% elongated state is maintained at 20°C for 24 hours and at 110°C for 10 minutes.

Using the cured powdered polymer of Example 1, melt spinning was carried out under the same conditions except that the temperature was 220°C. It was not possible to obtain extremely stable spinning operability.

This result shows that the process of melt-extruding powdered polymer and molding it into chips is essential for achieving stable spinning operability.

Example 2 The same operation as in Example 1 was performed using the composition shown in Table 2, and a powdery reaction product was obtained in a reaction time of 30 minutes.

Then, except for changing the melt extrusion temperature and spinning temperature,
Table 3 shows the performance of the obtained polyurethane elastic yarn, which was subjected to heat treatment under the same conditions as in Example 1.

Example 3 54 parts of polyethylene adipate with a molecular weight of 2000 and 6 parts of polytetramethylene glycol with a molecular weight of 2000, 15.7 parts of bis-hydroxyethylbenzene and 1,2.6 parts of bis-hydroxyethylbenzene
- Add and mix 0.1 part of hexandriol, 120
After being completely melted by heating at ℃, dehydration and drying treatment was carried out for 1 hour under conditions of 3 to 7 m□g at this temperature.

Next, the above molten mixture was poured into a kneader under a N2 gas flow, stirred, and when the S liquid temperature became constant at 100°C, 24.2 parts of 4,4-diphenylmethane diisocyanate was added, and the mixture was stirred for about 40 minutes. The contents became a powdery solid.

The composition in this case corresponds to R=1.04 and DC=1.8.

The powdered product thus obtained was dried for 1 hour under a N2 stream.
After curing at a temperature of 00° C. for 48 hours, melt extrusion was performed using a screw extruder at 200° C. with a residence time of 1 minute to form chips.

Using this chip, spinning and heat treatment were carried out in the same manner as in Example 1, except that the spinning temperature was changed to 203°C.

Table 4 shows the performance of the obtained polyurethane elastic yarn.

Example 4 The same operation as in Example 1 was carried out using the composition shown in Table 5, and a powdery reactive composition was obtained in a reaction time of 30 minutes.

Next, heat treatment was performed under the same conditions as in Example 1 except that the melt extrusion temperature and spinning temperature were changed.

The performance of the obtained polyurethane elastic yarn is shown in Table 6.

Claims (1)

[Scope of Claims] 1 consisting of an organic diisocyanate, a polyester having a molecular weight of 700 to 3000 and having hydroxyl groups at both ends, an aromatic diol, and an organic compound having at least 3 hydroxyl groups in one molecule, and 1 .00 to 1.10 and the polyester is 60 to 75
The weight-mixed polyurethane raw materials are homogeneously mixed in a reactor equipped with a stirring mechanism and a heating mechanism, and reacted. When the reaction product becomes powder, the product is taken out of the reaction system and then melt-extruded. A spun yarn obtained by molding a chip and then melt-spinning the chip is 100 to 150
A method for producing polyurethane elastic yarn, characterized by subjecting it to constant-length normal heat treatment at °C. 2. The method according to claim 1, wherein the organic diisocyanate is 4,4'-diphenylmethane diisocyanate. 3. The method according to claim 1, wherein the polyester is polyethylene adipate. 4. The method according to claim 1, wherein the aromatic diol has a molecular weight of 500 or less. 5. The method according to claim 1, wherein the aromatic diol is P-phenylene-di-β-oxynal ether and/or bis-hydroxyethylbenzene. 6. The method according to claim 1, wherein the organic compound has a molecular weight of 500 or less. 1. The method according to claim 1, wherein the organic compound is trimethylolpropane. 8. The method according to claim 1, wherein DC is 0.005 to 0.05. 9 Claim 1 in which R is 1.02 to 1.07
The method described in section. 10. The method according to claim 1, wherein the polyester is mixed in a weight ratio of 65 to 73. 11. The method according to claim 1, wherein the reaction temperature is 60 to 120°C. 12. The method according to claim 1, wherein the melt extrusion temperature is 230° C. or lower. 13. The method according to claim 1, wherein the melt spinning temperature is 230°C or lower. 14. The method according to claim 1, wherein the heat treatment temperature is 110 to 140°C.