JPH0411011A - Production of heat-resistant urethane yarn - Google Patents

Abstract

PURPOSE:To obtain the subject yarn having excellent heat-resistance and mechanical properties and useful for swimming wear, etc., by adding a specific polyisocyanate compound to molten polyurethane and spinning the mixture. CONSTITUTION:The objective thermoplastic polyurethane elastomer yarn can be produced by adding (A) preferably 10-25wt.% of a polyisocyanate compound produced by reacting (i) a bifunctional polyol component (e.g. polytetramethylene glycol), (ii) a trifunctional polyol component (e.g. a reaction product of glycerol, etc., with ethylene oxide, etc., having a molecular weight of preferably 300-3,000) and (iii) an isocyanate component (e.g. p,p'-diphenylmethane diisocyanate) wherein the molar ratio of the NCO group of the isocyanate component to the OH group of the polyol component is 1.5-2.0 to (B) a molten polyurethane and spinning the mixture in molten state.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to polyurethane elastic yarn,
Specifically, the present invention relates to a method for producing polyurethane elastic yarn with excellent heat resistance using a melt spinning method.

(Prior Art) There are three methods for producing polyurethane elastomers, which are broadly classified according to the spinning method: dry spinning, wet spinning, and melt spinning. Among these, the melt spinning method does not require the use of solvents,
It also has advantages such as high spinning speed and compatibility of equipment, and is advantageous as an industrial manufacturing method.

However, since the polyurethane elastomer obtained by the melt-spinning method uses thermoplastic polyurethane that can be melt-spun, it has problems such as poor heat resistance and insufficient recovery from deformation at high temperatures.

In order to solve this problem, the following methods have been proposed.

(1) A method of adding a polyfunctional compound during polymerization (2) A method of spinning directly from the polymerization system (3) A method of melt-spinning a semi-cured polymer and extruding it at a fixed isocyanate temperature or into the hardened side (4) After spinning Method of Heat Treatment (Problem to be Solved by the Invention) Regarding method (1) above, the melting temperature of the polymer increases if sufficient crosslinking is applied to improve heat resistance, so the spinning temperature is increased. This has the disadvantage that spinning becomes unstable.

Regarding method (2), it is difficult to control the polymerization reaction, there are problems such as retention and thermal stability in the process from the polymerization system to the spinning system, and the heat resistance of the resulting yarn is insufficient.

Methods (3) and (4) are effective in terms of the heat resistance of the urethane elastic yarn and its recovery from deformation at high temperatures, but the processing equipment is large and the cost is high for industrial manufacturing methods. This can be said to be disadvantageous.

In addition, we have developed a method for producing polyurethane elastic yarn with excellent heat resistance using the melt spinning method.
This is proposed in Publication No. 73.

In view of the current situation, the present inventors have made intensive studies to achieve the above object, and as a result have arrived at the present invention.The object of the present invention is to:
It is an object of the present invention to provide a method for producing elastic yarn with excellent heat resistance using a melt spinning method. Another object is to provide a stable and industrially advantageous manufacturing method for such polyurethane elastic yarns.

(Means for Solving the Problems) That is, the method for producing a heat-resistant urethane elastic yarn of the present invention involves the reaction of a bifunctional polyol component, a trifunctional polyol component, and an isocyanate component when melt-spinning a thermoplastic polyurethane elastomer. and the molar ratio (R) of the NCO groups of the isocyanate component to the OH groups of the polyol component.
is 1.5 or more and less than 2, is added to and mixed with molten polyurethane, and then subjected to moving yarn.

The diisocyanate components used in the thermoplastic polyurethane elastomer used in the present invention are p, p' diphenylmethane diisocyanate (hereinafter abbreviated as MDI), toluene diisocyanate (TDI), tetramethylene diisocyanate, hexamethylene diisocyanate (HMDI),
the HMD I derivative dodecamethylene diisocyanate;
Examples include xylylene diisocyanate, hydrogenated MDI, hydrogenated TDT, etc. Among these, MDI is preferable.The polyol component includes polytetramethylene glycol, polypropylene glycol, polycarbonate diol, polycaprolactone diol, and polyol component having a molecular weight of 500 to 5000. Neopenticine adipate 5 Using a diol containing at least one member selected from the group consisting of polyhexamethylene/butylene adipate copolymer, polycarbonate/hexamethylene adipate copolymer, and polyneopenticine/hexamethylene adipate copolymer. Polyols that have a Glycols are particularly preferred as the chain extender component, and include ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, bishydroxyethoxyhenzene, and the like.

As described above, in the present invention, as a thermoplastic polyurethane as a spinning raw material, a polymer synthesized without using a branching agent or a crosslinking agent is used in principle. For this reason, it is possible to keep the spinning temperature at a low level, and thermal deterioration of polyurethane can be suppressed.Of course, it is also preferable to use polymers containing branching or crosslinking that do not cause the spinning temperature to become extremely high. I can do it.

The thermoplastic polyurethane used in the present invention can be synthesized by the so-called prepolymer method, in which a polyol and an organic diisocyanate compound are reacted in advance, and then reacted with a chain extender, or the so-called one-shot method, in which all reaction raw materials are mixed at once. Either of these can be adopted. Although it is possible to use a solvent or diluent during polymer synthesis, bulk polymerization is more suitable for producing polymer pellets for melt spinning. As a method for bulk polymerization, a method of continuously or semi-continuously collecting a polymer using an extruder, or a method of obtaining a block, powder, or flake polymer by a batch reaction is preferably used.

In the present invention, in addition to completely thermoplastic polyurethane, which is used in the field of polyurethane elastomer molded products, and in which the polymer synthesis reaction has been fully completed, so-called incomplete thermoplastic elastomer, that is, pellets in which very few isocyanate groups remain, are used. It is also possible to cause crosslinking after molding. However, since such pellets have the problem of being susceptible to deterioration due to humidity, temperature, etc. during storage, it is convenient to use thermoplastic polyurethane that has undergone a complete reaction.

Next, the isocyanate component used in the polyisocyanate compound of the present invention is an organic diisocyanate used in the polymerization of thermoplastic polyurethane, such as p, p'-diphenylmethane diisocyanate (MDI), ) lylene diisocyanate (TDI), 1,5-naphthyl diisocyanate, Diisocyanate and the like can be suitably used. Alternatively, a trimer of organic diisocyanate isocyanate, trimethylolpropane, and the above diisocyanate are reacted,
Those having three NC0Is at the terminals, and di- to trifunctional isocyanates such as carbodiimide-modified isocyanates can be suitably used. Mixtures of these are also preferred, and the difunctional polyol components include polytetramethylene glycol, polypropylene glycol,
Polybutylene adipate, polycaprolactone diol.

Diols containing at least one diol such as polycarbonate diol can be suitably used. The molecular weight of this bifunctional compound is preferably 400 or more, particularly 800 to 5000, from the viewpoint of physical properties and handling of the compound.

Trifunctional polyol components include glycerin and Trino F.
- an alkylene oxide (e.g. ethylene oxide,
peropylene oxide, etc.), or polycaprolactone triols, which are polymerized with ε-caprolactone etc. using trimethylolpropane as an initiator (for example, PLACCEL300).
Series: manufactured by Daicel Chemical Industries, Ltd., etc.) can also be suitably used. The molecular weight of this trifunctional polyol is 30
A range of 0 to 3000 is preferred.

The usage ratio of the above-mentioned bifunctional and trifunctional polyol components is arbitrary, but the average functionality is 2.02 to 3.0, especially 2.0.
A range of 5 to 2.50 is preferred, where the average functionality (
F) is a value calculated by: F-2X (mole fraction of difunctional component) + 3x (mole fraction of trifunctional component). If the trifunctional polyol component is too small, the resulting yarn will have poor heat resistance, and if the trifunctional polyol component is too large, the viscosity of the polymerization system will become high, causing problems in handleability and other operability, which is not preferable.

Examples of synthetic polyols having an average functionality in the range of 2.02 to 3.0 include low molecular weight diol components (e.g. ethylene glycol, propylene glycol, diethylene glycol) and the above low molecular weight triols (e.g. hexane triol, triol). methylolpropane-5-glycerin, etc.) and a low molecular weight dibasic acid (e.g., adipic acid, succinic acid, maleic acid, etc.) with a molecular weight of 1000 to 40.
00 polycondensation polyester polyol (for example, Des
mophen 2200 (manufactured by Bayer AG, etc.) can be suitably used.

The polyisocyanate compound can be polymerized from the polyol component and the isocyanate component by a known method, but in this case, the molar ratio R of the NGO group of the isocyanate component to the OH group of the polyol component is 1.5 or more and less than 2. It is necessary to react so that

The amount of the daughter polyisocyanate compound added is preferably 5 to 40% by weight, particularly preferably 10 to 25% by weight, based on the total amount of the thermoplastic polyurethane elastomer to be subjected to spinning and the polyisocyanate compound. . This ratio may be determined to satisfy the desired physical properties of the yarn.
For example, it is preferable to appropriately determine the amount based on the molecular weight of the polyisocyanate compound used, the amount of free isocyanate, etc. However, if this amount is too large, the mixing may become uneven, making spinning impossible, or the mechanical properties of the resulting yarn may deteriorate. This is not preferable because it tends to cause deterioration, and if the amount added is small, the desired improvement in the thermal performance of the urethane thread will be insufficient.

The production of the yarn of the present invention is preferably carried out using, for example, a melt-spinning apparatus 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 the mixing part, for example, a static kneader is preferable because it is a simple device. As this static kneader, known ones such as a static mixer manufactured by K-EX Co., Ltd. and a high mixer manufactured by Toshisha Co., Ltd. can be suitably used.

The shape and number of elements of this mixer will vary depending on the conditions of use, but should be selected so that sufficient mixing of the polyurethane elastomer and polyisocyanate compound is completed before they are discharged from the spinneret. This is important, and usually 20 to 90 elements are provided.

An example of an embodiment of the present invention will be described below.

A pellet of thermoplastic polyurethane elastomer is supplied from a hombur and heated and melted in an extruder. Melting temperature is 190-2
A range of 30°C is preferred. On the other hand, the polyisocyanate compound melts at a temperature below 100°C in the supply tank,
The polyisocyanate compound is defoamed in advance. If the melting temperature is too high, the polyisocyanate compound tends to deteriorate, so it is preferably as low as possible within the melting range, and a temperature between room temperature and 100° C. is appropriately used. The molten polyisocyanate compound is metered by a metering pump, filtered if necessary by a filter, 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 stationary kneading element.

This mixture is metered by a metering pump and introduced into the spinning head. It is preferable to design the spinning throat in a shape that minimizes the retention area of the mixture as much as possible. If necessary, after removing foreign matter with a filter layer provided in the spinning head using a filter medium such as a wire mesh or glass beads, the mixture is is discharged from the mouthpiece, cooled in air, coated with oil, and then rolled up. The I-chip speed is usually 400 to 1500 m/
minutes are used.

Urethane yarn wound onto a spinning bobbin may have poor strength immediately after spinning, but if it is left at room temperature (for example, 2
The strength is improved within 6 days) and the recovery properties from elongation at high temperatures are also improved. Further, by applying heat treatment by an appropriate method after spinning, improvement of yarn quality and thermal properties is promoted. The reason why the yarn quality and thermal performance of the urethane elastic yarn spun as described above change over time is that the reaction between the thermoplastic polyurethane elastomer used as a spinning raw material and the mixed polyisocyanate compound occurs during spinning. It is presumed that this is because the process continues even after spinning without being completed. This reaction is considered to be the formation of a branched or crosslinked polymer due to allophanate bonds between the polyurethane and the polyisocyanate compound.

Below, preferred embodiments of the present invention will be summarized and described.
.

(1) The method according to claim 1, wherein the organic diisocyanate used in the polyisocyanate compound is p,p-diphenylmethane diisocyanate.

(2) As the polyol constituting the polyisocyanate compound, the bifunctional polyol component has a molecular weight of 500 to 50
00 polytetramethylene glycol, polypropylene glycol, polybutylene adipate, polycaprolactone diol.

2. The method according to claim 1, wherein the diol contains at least one selected from the group consisting of polycarbonate diols, and the trifunctional polyol component is a polycaprolactone-based polyester triol having a molecular weight of 300 to 3,000.

(3) Average functionality of polyol component is 2.02 to 3.0
The method according to claim 1.

(4) The polyol used in the thermoplastic polyurethane elastomer is polytetramethylene glycol having a number average molecular weight of 500 to 5,000, polycaprolactone diol, polybutylene adipate, polyhexamethylene adipate, polycarbonate diol, polyneopenticine adipate . At least one selected from the group consisting of polyhexamethylene/butylene adipate copolymer, polycarbonate/hexamethylene adipate copolymer, 1 bolineopentylene hexamethylene adipate copolymer.
2. The method of claim 1, wherein the polyol is a species-containing polyol.

(5) The method according to claim 1, wherein the chain extension side used in the thermoplastic polyurethane elastomer is a glycol or triol with a molecular weight of 500 or less.

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

(7) Is the proportion of polyisocyanate compound thermoplastic? The method according to claim 1, wherein the amount is 5 to 40% by weight based on the total weight of the tan and the polyisocyanate compound.

(8) The method according to claim 1, wherein the mixing is carried out using a device equipped with a static kneading element.

C) Effects of the present invention) The production method of the present invention is essentially a melt spinning method, and has advantages over industrial production, such as no need for solvent recovery and a fast winding speed. Furthermore, since the urethane yarn obtained by the present invention has excellent heat resistance and mechanical properties, it can be suitably used in various applications (for example, swimwear, foundations, sonx, etc.).

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 <Polyisocyanate compound> The molar ratio of bifunctional/trifunctional polyol component was 8/2 (
64.2 parts of dehydrated polybutylene adipate with a molecular weight of 1520 and a dehydrated trifunctional polycaprolactone triol with a molecular weight of 860 (manufactured by Daicel Chemical Industries, Ltd.: average functionality = 2.20) and R = 1.84.
9.1 parts of PLACCEL 308) were reacted with 26.7 parts of p,p/diphenylmethane diisocyanate at a temperature of 80°C in a polymerization kettle equipped with a stirrer,
A viscous polyisocyanate compound (A) was obtained.

In a similar manner, the 2/3 functional molar ratio of the polyol component was changed as shown in Table 1, and p was adjusted so that R = 1.84.
p'-diphenylmethane diisocyanate was reacted to obtain polyisocyanate compounds (B, C).

<Thermoplastic polyurethane elastomer> Molecule i! 66.9 parts of polyhexamethylene adipate diol of 2030 and 6.3 parts of 1,4-butanediol were placed in a jacketed kneader, and after sufficiently melting with stirring, the mixture was kept at a temperature of 85°C. p,
p/-diphenylmethane diisocyanate 26.8
part was added and reacted. The obtained reaction product was taken out from the kneader and molded into a pellet shape using an extruder. This molded article had a relative viscosity of 2.16 in dimethylformamide at 25°C.

The beleft of the thermoplastic polyurethane elastomer obtained in this manner and the polyisocyanate compounds (A, B, C) are used as spinning raw materials, and a polyisocyanate compound supply device and a static kneading element 25 element (static kneading element manufactured by Kenix Co., Ltd.) are used as spinning materials. Melt spinning was performed using a spinning machine equipped with a kneading device (mixer). The mixed melt has a diameter of 0
．． Guided to a 5mm spinning nozzle, winding speed 600m/
A 40 denier filament urethane elastic yarn was obtained in minutes.

Table 1 shows the results of spinning with the amount of polyisocyanate compound added to polyurethane at 18%. This is the value. The heat cent recovery rate at 190°C is the recovery rate when 30% elongated (1) is heat treated at 190°C for 1 minute and then relaxed to room temperature, and was calculated using the following formula.

The larger this value is, the better the heat resistance is.

From Table 1, it can be seen that by increasing the molar ratio of the 2/3 functional component in the polyol component, the heat set recovery rate also increases and the heat resistance is improved.

On the contrary, it can be seen that the polyisocyanate compound reacted only with a difunctional polyol without adding a trifunctional polyol component has very poor heat resistance.

Claims (1)

[Claims] (1) When melt-spinning a thermoplastic polyurethane elastomer, the bifunctional polyol component, the trifunctional polyol component, and the isocyanate component are reacted, and the molar ratio of the NCO group of the isocyanate component to the OH group of the polyol component is 1. A method for producing heat-resistant urethane yarn, which comprises adding and mixing a polyisocyanate compound having a molecular weight of .5 or more and less than 2 to molten polyurethane, followed by spinning.