JP2613858B2 - Manufacturing method of polyurethane elastic yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a method for producing a polyurethane elastic yarn. More specifically, the present invention relates to a method for preventing scale precipitation in a molten polymer flow channel by a melt spinning method, and excellently. The present invention relates to a method for producing a polyurethane elastic yarn having heat resistance and anti-sticking property.

<Prior Art> In general, wet spinning or dry spinning is used for the production of polyurethane elastic yarn, and there are relatively few cases in which melt spinning is used. This is because when a polyurethane elastic material is melt spun, it is generally difficult to stably operate the polyurethane elastic material for a long time due to poor thermal stability during melting, and the polyurethane elastic yarn obtained by melt spinning is heat resistant. This is considered to be due to the following disadvantages: poor recovery from deformation at high temperature, insufficient adhesion of fibers, and difficulty in unwinding the yarn.

Several methods have been proposed to improve the disadvantages of the melt spinning method. For example, Japanese Patent Publication No. 44-20247 proposes a method for improving heat resistance by adding a special polyfunctional compound during the synthesis of polyurethane. Japanese Patent Publication No. 43-7426 proposes a method of synthesizing a polyurethane using a polyfunctional polyol and melt-spinning the polyurethane.

On the other hand, as a method for preventing sticking in the melt spinning method, various studies have been made on various spinning oil agents or various additives. For example, amide wax during polymerization,
A method of adding silicon or the like has been adopted. Improvements have been attempted by blending modified silicon and active isocyanate blocking agents such as monoamines as spinning oils.

<Problems to be Solved by the Invention> However, a method of improving the heat resistance of polyurethane elastic yarn by giving a cross-linking to polyurethane with these polyfunctional compounds, when a sufficient degree of cross-linking is provided to improve the heat resistance, Since the melting temperature of the polymer increases, it becomes necessary to increase the spinning temperature. As a result, not only is thermal decomposition of the polyurethane likely to occur and spinning becomes unstable, but also scale is deposited in the molten polymer flow path, making long-term operation difficult.

On the other hand, among the methods for preventing sticking, regarding the additives during polymerization, the polymerization of polyurethane is alienated, the compatibility with the polymer is poor, and when the amount of addition is large, a slip phenomenon occurs on the screw of the extruder, and so-called erosion occurs. Cause a malfunction. In some cases, there is a further disadvantage that white powder is generated on a guide or the like in a post-process such as rewinding of a urethane yarn. Regarding the spinning oil, even if the anti-sticking ability can be improved, slippage occurs between the yarns, making it impossible to wind up. There is a problem that it is difficult.

As described above, a method for stably producing a polyurethane elastic yarn having excellent heat resistance and improved anti-sticking properties over a long period of time without depositing scale or the like in a polymer channel by a melt spinning method has been found. Absent.

<Problems to be Solved by the Invention> The present inventors have made intensive studies to improve the above-mentioned drawbacks, and as a result, have reached the present invention.

An object of the present invention is to provide a polyurethane elastic yarn having excellent heat resistance and improved anti-sticking property. Another object is to provide a method for producing such a polyurethane elastic yarn in a stable and industrially advantageous manner without depositing scale by a melt spinning method.

<Means for Solving the Problems> That is, in the method of the present invention, when melt-spinning a thermoplastic polyurethane elastic material, at least a diisocyanate is polymerized from a polyol component containing a silicone diol and a diisocyanate component and is reacted with an OH group of the polyol component. A method for producing a polyurethane elastic yarn, which comprises adding a prepolymer compound having a molar ratio of NCO groups in a range of 2 to 4 to a molten polyurethane, followed by spinning, followed by spinning.

Examples of the polyol component constituting the prepolymer compound of the present invention include bifunctional polyols such as polytetramethylene glycol, polypropylene glycol, polybutylene diol, polycaprolactone diol, and polycarbonate diol, and trifunctional polyols composed of caprolactam and trimethylolpropane. Can be suitably used. In addition to the polyols described above, primary alcoholic OH is added to both ends of dimethylpolysiloxane to impart non-adhesiveness to the obtained urethane yarn and to impart properties such as thermal oxidation stability and lubricity to the prepolymer compound. Silicol diols with groups are required.

Organic diisocyanates which are the other prepolymer constituents include p, p'-diphenylmethane diisocyanate, toluylene diisocyanate, hydrogenated p, p'-diphenylmethane diisocyanate, tetramethylene diisocyanate, 1,5-naphthalenediisoyanate, and isophorone. Diisocyanate and the like can be used. Preferably, p, p'-diphenylmethane diisocyanate is used. The above organic diisocyanate component NC
Ratio R = y / x between y mole of O group and x mole of polyol component OH group
May be in the range of 2 ≦ R ≦ 4 in order to leave a free diisocyanate component in order to increase the heat resistance of the obtained yarn and to give much to the allophanate crosslinking reaction in the yarn. Preferably, it should be appropriately selected depending on the molecular weight of the polyol, but R is preferably in the range of 2.1 to 3.0.

The weight ratio of the silicone diol in the entire polyol component is based on the total weight of the polyurethane and the prepolymer.
It is preferably at least 0.02% by weight. If the amount is less than 0.5% by weight, the effects of the present invention of preventing sticking and preventing precipitation of scale will be insufficient.

The thermoplastic polyurethane elastic body applied to the present invention includes a known segment polyurethane copolymer,
A polyol having a molecular weight of 500 to 6000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polylactone, dihydroxy polyester amide, dihydroxy carbonate, and a block copolymer thereof; and an organic diisocyanate 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, iriphorone diisocyanate, p, 5-naphthalene diisocyanate, and a chain extender such as It is a polymer obtained by reaction with water, hydrazine, diamine, glycol and the like. Of these polymers, particularly preferred are polytetramethylene ether glycol or polycaprolactone polyester diol, polyhexamethylene adipate diol, polycarbonate diol, polyhexamethylene / butylene adipate copolymerized diol, and polycarbonate / hexamethylene copolymer. It is a polymer using a diol or the like. As organic diisocyanates, p,
p'-Diphenylmethane diisocyanate is preferred. Glycol is particularly preferred as a chain extender.
4-bis (β-hydroxyethoxy) benzene and 1,4
Butanediol is preferred.

As described above, in the present invention, a polymer synthesized without using a branching agent or a cross-linking agent is used as a thermoplastic polyurethane as a spinning raw material in principle. For this reason, the spinning temperature can be kept at a low level, and the thermal deterioration of the polyurethane can be suppressed. Of course, a polymer containing branching or cross-linking to such an extent that the spinning temperature is not extremely increased can also be suitably used.

As a method for synthesizing a thermoplastic polyurethane elastic material used in the present invention, a so-called prepolymer method in which a polyol and an organic diisocyanate compound are reacted in advance and then a chain extender is reacted, and a so-called prepolymer method in which all of the reaction raw materials are mixed at a time, Either one-shot method can be adopted. Although it is possible to use a solvent or a diluent during the synthesis of the polymer, it is more preferable to carry out bulk polymerization in order to produce polymer pellets for melt spinning. As the bulk polymerization method, a method of continuously or semi-continuously collecting a polymer using an extruder, a method of obtaining a powdery or flake-like polymer by a batch reaction, and the like are suitably used.

In the present invention, a polyurethane in which a polymer synthesis reaction has been sufficiently completed can be used as a spinning raw material. In the field of molded polyurethane elastomers, there is known a method of using a so-called incomplete thermoplastic elastomer, that is, a pellet in which an active group such as an isocyanate group partially remains to cause crosslinking after molding. However, there is a problem that such pellets are liable to be deteriorated due to humidity, temperature and the like during storage. In the present invention, it is possible to use such an incomplete thermoplastic elastomer, but a thermoplastic polyurethane which has been completely reacted for the above-mentioned reason is preferably used.

In the present invention, the amount of the prepolymer compound to be added is preferably 3 to 40% by weight based on the mixture of the thermoplastic polyurethane elastic material to be spun and the prepolymer compound.
Particularly preferably, it is 15 to 30% by weight. The amount added depends on the molecular weight of the prepolymer compound used, the amount of free diisocyanate, etc., but if the amount is small, the improvement of the thermal performance of the target urethane yarn is insufficient, and If the amount is too large, mixing is not uniform, and winding during spinning becomes impossible, which is not preferable.

The melt spinning of the present invention is preferably carried out by a spinning apparatus having a portion for extruding a thermoplastic polyurethane elastic body, a portion for adding and mixing a prepolymer compound, and a spinning head. As such a spinning device,
Known devices used for adding a modifier during spinning can be used.

It is also possible to use a kneading device having a rotating part in the portion where the prepolymer compound is added and mixed with the polyurethane in a molten state, but it is more preferable to use a mixing device having a static kneading element. . A well-known mixing device having a stationary kneading element can be used. The shape and number of stationary kneading elements vary depending on the conditions used, but are selected so that the polyurethane elastic prepolymer compound is sufficiently mixed before being discharged from the spinneret. It is important.

 Hereinafter, an example of an embodiment of the present invention will be described.

Pellets of thermoplastic polyurethane elastic material are supplied from a popper and heated and melted by an extruder. Melting temperature is 190-2
A range of 30 ° C. is preferred. On the other hand, the prepolymer compound is melted in the supply tank at a temperature of 100 ° C. or less, and defoamed in advance. If the melting temperature is too high, the prepolymer compound is liable to be deteriorated, so that the melting temperature is preferably as low as possible, and a temperature between room temperature and 100 ° C. is appropriately used. The molten prepolymer compound is measured by a measuring pump,
If necessary, filter with a filter. The weighed prepolymer compound is added to the polyurethane melted at an associated portion provided at the extruder tip, and kneaded by 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, an ordinary synthetic fiber spinning apparatus can be used, but it is preferable that the spinning head is designed to have a shape in which the mixture stays as little as possible. If necessary, after removing foreign matter with a filter such as a wire mesh or glass beads in a filter layer provided in the spinning head, the mixture is discharged from a die, air-cooled, applied with an oil agent, and wound up. A winding speed of usually 400 to 1500 m / min is used. The urethane yarn wound on the spinning bobbin is
Although the strength may be inferior immediately after spinning, the strength is improved when left at room temperature, and the recovery characteristics from elongation at high temperatures are also improved.

 Preferred embodiments of the method of the present invention will be described below.

(A) The method according to claim 1, wherein the polyol component constituting the prepolymer compound contains a bifunctional and / or trifunctional polyol.

(B) The method according to claim 1, wherein the silicone diol in the polyol component constituting the prepolymer compound has a primary alcoholic hydroxyl group at both ends of dimethylsiloxane.

(C) The method according to claim 1, wherein the diisocyanate component forming the prepolymer compound is p, p'-diphenylmethane diisocyanate.

(D) 50 polyols forming thermoplastic polyurethane
Polytetramethylene glycol, polycaprolactone diol, polybutylene adipate diol, polyhexamethylene adipate diol, polycarbonate diol, polyhexamethylene / butylene adipate copolymer diol, polyhexamethylene / carbonate copolymer having a number average molecular weight of 0 to 6000 The method according to claim 1, which is a polyol containing at least one member selected from the group consisting of diols.

The method according to claim 1, wherein (e) the chain extender forming the thermoplastic polyurethane elastic body is glycol or triol having a molecular weight of 500 or less.

(F) The method according to claim 1, wherein the organic diisocyanate forming the thermoplastic polyurethane elastomer is p, p'-diphenylmethane diisocyanate.

2. The method according to claim 1, wherein the amount of the prepolymer compound added is 3 to 40% by weight based on the total weight of the thermoplastic polyurethane elastomer and the polymer.

2. The method according to claim 1, wherein the mixing is performed by an apparatus provided with a stationary kneading element.

<Effects of the Invention> According to the method of the present invention, precipitation of scale in the mixed polymer flow path is prevented, trouble does not occur in the spinning operation for a long period of time, and the wound yarn has a large sticking. It has the great advantage of being improved in width. Further, the yarn obtained by the method of the present invention has excellent heat resistance only by being left at room temperature, so that it can be applied to various uses such as socks, swimsuits, foundations and the like, in particular, fields where heat resistance is required. is there.

(Examples) Hereinafter, the present invention will be described with reference to examples.

Example 1 5548 parts of dehydrated polyhexamethylene adipate diol having a hydroxyl value of 102 (all parts below mean parts by weight)
499 parts of 1,4-bis (β-hydroxyethoxy) benzene was charged into a jacketed kneader, melted sufficiently with stirring, maintained at a temperature of 85 ° C., and 1953 parts of p, p′-diphenylmethane diisocyanate was added thereto. The reaction was performed.
The obtained reaction product was taken out of the kneader, and formed into pellets by an extruder, and the mixture was heated at 25 ° C.
Thus, a thermoplastic polyurethane having a concentration of 1 g / dl and a relative viscosity of 2.31 was measured. On the other hand, 56 parts of holica prolactodiol having a hydroxyl value of 132, 1 part of silicone diol having a hydroxyl value of 112 (X-22-160AS manufactured by Shin-Etsu Chemical Co., Ltd.), and R of 2.5 parts
P, p'-diphenylmethane diisocyanate to be 7
43 parts was reacted at 80 ° C. for 30 minutes to obtain a viscous prepolymer compound. The compound was further degassed by applying a vacuum.

Using the thus obtained prepolymer compound and thermoplastic polyurethane pellets as a spinning raw material, spinning was performed by a spinning machine equipped with a prepolymer compound supply press-in device and a kneading device having a static kneading element. 0.5mm diameter noise is used as the spinneret and the winding speed is 500
40 denier monofilament was spun at m / min. As the spinning oil, 8% of SPK-124 manufactured by Takemoto Yushi Co., Ltd. (comprising 5% of modified silicon mainly composed of mineral oil)
Granted. Table 1 shows the results obtained by changing the amount of the prepolymer compound to be added to the thermoplastic polyurethane and further depending on the presence or absence of the silicone diol in the prepolymer.

The yarn quality, heat resistance, and unwinding coefficient in Table 1 are values measured after the spun urethane yarn bobbin was allowed to stand at room temperature for 5 days.

The 190 ° C heat set recovery rate is the recovery rate when a 30% stretched urethane yarn is heat-set at 190 ° C for 1 minute. The larger the value, the better the heat resistance.

The unwinding coefficient is defined as the smallest unwound yarn that is unwound without being wound around the bobbin when the yarn is unwound while rolling the bobbin of the urethane yarn on a drive roller at a speed of 50 m / min. The draft rate of the yarn at the take-up speed.
It shows that the effect of preventing the thread from sticking is larger as the value is closer to.

For the scale deposition, the pressure at the outlet of the extruder and the pressure before the metering gear pump of the spinning head were measured, and it was judged that the scale was deposited when the pressure difference between them, that is, the pressure loss started to increase. Therefore, the longer the number of days from the start of the spinning operation until the pressure loss starts to increase, the larger the effect of preventing scale deposition.

When no prepolymer compound is added from Table 1,
Although the unwinding property is good and the scale does not break out, the essential heat resistance is so poor that the yarn is melted and cut during the measurement and the measurement becomes impossible. However, it can be seen that the heat set recovery rate is increased and the heat resistance is improved by adding the prepolymer compound and spinning. Also, the larger the amount added,
The heat resistance improvement effect also increased.

However, conversely, the sticking between the yarns increased as the amount of addition increased, and it became difficult to unwind the yarns. On the other hand, when the prepolymer compound containing the silicone diol was added, sticking was greatly improved, and there was no problem in unwinding the yarn even if the amount of the prepolymer compound was large. Regarding the precipitation of scale, when a prepolymer compound containing no silicon diol component was added, it was precipitated in about 25 to 28 days, but in the case of the prepolymer compound of the present invention, it did not precipitate even after 2 months,
Operability has been greatly improved. Therefore, it was found that by adding the prepolymer compound containing the silicon diol component of the present invention and spinning, the effects of improving heat resistance, preventing sticking, and preventing scale deposition were increased.

Example 2 Except for changing the R ratio, the same thermoplastic polyurethane and the same composition as in Example 1 were used, using the same prepolymer compound.
Spinning was performed in the same manner as in Example 1. The amount of the prepolymer compound added was fixed at 15% by weight. This result is
It is shown in the table.

Table 2 shows that when the prepolymer compound of the present invention is spun, the operability of the yarn in terms of unwinding property and scale precipitation is greatly improved. However, there is no free diisocyanate component in the prepolymer compound.
1 and 2-2 with free diisocyanate
It can be seen that the heat resistance is significantly different from the yarn of 2-4, and the heat resistance increases as the R ratio increases.

Claims (1)

(57) [Claims] When a thermoplastic polyurethane elastic material is melt-spun, at least a polyol component containing silicone diol and a diisocyanate component are polymerized, and the molar ratio of NCO groups of the diisocyanate component to OH groups of the polyol component is 2 to 4. A method for producing a polyurethane elastic yarn, comprising adding and mixing a prepolymer compound in the range of (1) to a molten polyurethane, followed by spinning.