JPH03241013A - Heat-resistant conjugate elastic yarn having improved light-resistance - Google Patents

Abstract

PURPOSE:To obtain the subject elastic yarn having excellent light resistance, mechanical properties and thermal properties and suitable for industrial production by using a non-yellowing thermoplastic polyurethane elastomer as the sheath and a reaction product of a thermoplastic polyurethane elastomer and a polyisocyanate compound as the core component. CONSTITUTION:The objective elastic yarn is composed of a sheath consisting of a non-yellowing thermoplastic polyurethane elastomer and a core consisting of a reaction product of a thermoplastic polyurethane elastomer, a bifunctional polyol component a trifunctional polyol component and an isocyanate component having an isocyanate NCO content of 2-15wt.%. The color fading measured after 40hr irradiation test in conformity with JIS L-0842 is higher than class 4, the yarn does not melt and break within 1min when maintained in air of 190 deg.C in a state stretched by 30%, the recovery is >=3% when relaxed at room temperature and the 40% creep temperature in the temperature-elongation creep curve is >=130 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyurethane elastic conjugate fiber that has excellent light resistance and improved mechanical and thermal properties.

(Prior Art) Polyurethane elastic threads have been used for various purposes due to their excellent properties. However, from the viewpoint of mechanical strength and heat resistance, these skeletons contain diisocyanates containing aromatic groups, such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI).
Although it is superior in the above points, it has the drawbacks of large discoloration when exposed to light and significant deterioration of mechanical properties.

Conventional countermeasures for this problem include: ■ Improvements using additives: For example, improvements by adding benzotriazole-based UV absorbers, hindered amine-based UV stabilizers, etc.; ■ Improvements in the polymer skeleton: For example, from non-yellowing diisocyanates such as hexamethylene diisocyanate. (1) Improvement by composite: For example, a method using a non-yellowing polyurethane on the sheath component side and a polyurethane having a normal aromatic ring on the core component side (for example, Japanese Patent Publication No. 7167/1983); Alternatively, a method using polyolefin on the sheath component side (
Various approaches have been taken, such as Japanese Patent Laid-Open No. 61-194221).

(Problems to be Solved by the Invention) However, although the improvement using additives (2) is effective in short-term light tests, it becomes almost ineffective when the test conditions become severe, and there is a limit. In direction (2), only dry, wet, or melt spinning using this polymer results in unsatisfactory results in terms of strength, recovery properties, heat resistance, etc.

Also, among the items in ■, the former yarn has good yellowing, but
The mechanical strength is insufficient at about 0.6 g/d, and the method of obtaining this yarn is a coating method or dry/wet spinning, which is disadvantageous in terms of productivity.

On the other hand, the latter has the disadvantage of insufficient heat resistance.

An object of the present invention is to provide a new polyurethane composite elastic yarn that has excellent light resistance, excellent mechanical properties and thermal properties, and is also advantageous for industrial production.

(Means for Solving the Problems) In view of the current situation, the inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, have arrived at the present invention.

That is, the heat-resistant composite elastic yarn with improved light resistance according to the present invention has a thermoplastic and non-yellowing polyurethane elastomer as a sheath, and a reaction between the thermoplastic polyurethane elastomer and a polyisocyanate compound. The polyisocyanate compound is a polymer of a bifunctional polyol component, a trifunctional polyol component, and an isocyanate component, and the isocyanate NCO content in the polymer is in the range of 2 to 15% by weight. characterized by something.

In a preferred embodiment, the heat-resistant composite elastic yarn of the present invention conforms to JIS
The discoloration and fading after a 40-hour irradiation test with L-0842 was grade 4 or higher, and the thread was 19% stretched when stretched by 30%.
It does not melt and break within 1 minute when placed in an air atmosphere at 0°C, and the recovery rate when the chain yarn is relaxed to room temperature is 3% or more, and it also has a temperature-elongation creep property. In the curve, the temperature at 40% creep is 130°C or higher.

The present invention will be explained in detail below.

The thermoplastic and non-yellowing polyurethane elastomer used in the sheath component of the present invention includes diisocyanate components such as tetramethylene diisocyanate, hexamethylene diisocyanate (HMDI), derivatives of HMDI, dodecamethylene diisocyanate, xylylene diisocyanate, etc. Isocyanate, water added MDI.

The polyol component is polytetramethylene glycol, polypropylene glycol, polycarbonate diol, polycaprolactone diol, polyhexamethylene glycol, etc., and the chain extender component is ethylene glycol, propylene glycol,
Examples include those consisting of three components such as tetramethylene glycol, hexamethylene glycol, and bishydroxyethoxybenzene. Examples of suitable polymers include "Vandex T-R3080" (manufactured by Dainippon Ink and Chemicals) and "Miractran E 785".
There are PSDI ('' (manufactured by Nippon Miractran), etc.).

It is also suitable that the non-yellowing polyurethane elastomer, which is the sheath component, contains additives such as antioxidants, lubricants, antibacterial agents, and antifungal agents.

On the other hand, in the thermoplastic polyurethane elastomer used as one of the core components of the present invention, it is important that the diisocyanate component is an aromatic diisocyanate in order to provide mechanical and thermal properties, such as MDI, TDI
, 1,5-naphthylene diisocyanate, phenylene diisocyanate, etc., and p,p'-diphenylmethane diisocyanate is particularly preferred. As the other two components, the polyol component and the chain extender component, compounds used for the above-mentioned non-yellowing polyurethane elastomer can be suitably used.

As the bifunctional polyol component constituting the polyisocyanate compound which is one of the reaction components of the core component, diols containing at least one of polytetramethylene glycol, polypropylene glycol, polybutylene adipate, polycaprolactone diol, polycarbonate diol, etc. are preferably used. can.

The molecular weight of this bifunctional substance is 400 or more, especially 500-
3000 is preferable in view of the physical properties of the compound obtained and handling.

On the other hand, as the trifunctional polyol component, polyether triol obtained by addition polymerization of alkylene oxide (e.g. ethylene oxide, propylene oxide, etc.) in the presence of an initiator such as glycerin, trimethylolpropane, hexanetriol, etc., or trimethylolpropane, etc. A polycaprolactone triol prepared by polymerizing ε-caprolactone etc. as an initiator [for example, Plaxel (PL
ACCEL) 300 series: manufactured by Daicel Chemical Industries, Ltd.] etc. can also be suitably used.

The usage ratio of the above-mentioned bifunctional and trifunctional polyol components is arbitrary, but 97/3 to 20/80, especially 9515 to 50
A range of 150 is preferred. If this trifunctional polyol component is too small, the heat resistance of the yarn obtained will be poor, and if the content is too large, the viscosity of the polymerization system will become high, causing problems in handling and other operability. So I don't like it.

Other examples of bifunctional and trifunctional polyols include low molecular weight diol components (e.g. ethylene glycol, propylene glycol, diethylene glycol), and the above low molecular weight triols (e.g. hexanetriol, trimethylolpropane, glycerin, etc.) and low molecular weight diol components (e.g. ethylene glycol, propylene glycol, diethylene glycol), etc. A polycondensation polyester polyol (for example, Desmophen 2200, manufactured by Bayer AG) consisting of a dibasic acid (for example, adipic acid, succinic acid, maleic acid, etc.) can be suitably used.

Next, the isocyanate component constituting the polyisocyanate compound is not a non-yellowing type diisocyanate among organic diisocyanates, but an aromatic diisocyanate, such as p, p' diphenylmethane diisocyanate, tolylene diisocyanate, (1), 5-naphthylene diisocyanate, etc. Isocyanates and the like can be suitably used. Among these, p,p'-diphenylmethane diisocyanate is preferred.

A known method can be used to polymerize a polyisocyanate compound from the above polyol component and isocyanate component. It is sufficient if the reaction is carried out in such a manner that the amount is % by weight. At this time, if the viscosity of the system increases and defoaming becomes difficult, a defoaming agent may be added to the system in advance.

The amount of the polyisocyanate compound added in the core component of the present invention is 5 to 40% by weight based on the mixture of the polyisocyanate compound and the thermoplastic polyurethane elastomer to be subjected to spinning. 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. Also,
If the amount added is too large, the spinning may become unstable due to non-uniform mixing, and the mechanical properties of the yarn may be unsatisfactory, which is not preferable.

The structure of the core-sheath core components has been described above, and next, the composite ratio of the core-sheath components will be described. The composite ratio of this core-sheath component is 75/25 or more, especially 85/15 to 95 in terms of fiber cross-sectional area ratio.
A range of 15 is preferred. When the ratio of the sheath component is 25% or more, the resulting yarn has improved elastic recovery properties, recovery properties from high temperatures,
Heat resistance is insufficient, and on the other hand, if the core component exceeds 95%, the sheath component is likely to tear and the core component is likely to be exposed on the yarn surface, which is undesirable since it has an adverse effect on spinnability and light resistance.

Next, a method for manufacturing the yarn of the present invention will be explained.

By means of a melt composite spinning apparatus comprising a part for melt extruding a thermoplastic polyurethane elastomer, a part for adding and mixing a polyisocyanate compound, a part for melt extruding a sheath component, and a spinning head having a known core-sheath type composite spinneret. It is suitable to carry out. A known device can be used to add the polyisocyanate compound during spinning. Although it is possible to use a kneading device with a rotating part in the part where the polyisocyanate compound is added to and mixed with the molten polyurethane, it is more preferable to use a mixing device with a stationary kneading element. be. As the mixing device having a stationary kneading element, a known mixing device can be used. The shape and number of elements of the stationary kneading element will vary depending on the conditions of use, but should be selected so that sufficient mixing of the thermoplastic polyurethane elastomer and the polyisocyanate compound is completed before they are discharged from the composite spinneret. It is important that
Usually 20 to 90 elements are provided.

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

Pellets of thermoplastic polyurethane elastomer are supplied from a hopper 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 is
It is melted at a temperature of 0°C or lower and defoamed beforehand. If the melting temperature is too high, the quality of the polyisocyanate compound is likely to change, so a temperature as low as possible within the melting range is desirable, and a temperature between room temperature and 100° C. is appropriately used. Measuring the molten polyisocyanate compound using a metering pump,
If necessary, it is filtered through 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 that the spinning head is designed to have a shape that has as few retention areas as possible for the mixture. If necessary, after removing foreign substances using a filtering layer such as a wire mesh or glass beads in a filtration layer provided in the spinning head, the mixture is joined to a thermoplastic and non-yellowing polyurethane elastic body as a sheath component in a core-sheath shape, It is then discharged from the nozzle, cooled in the air, coated with oil, and then rolled up. The winding speed is usually 4.
00 to 1500 m/min is used.

The heat-resistant elastic yarn wound onto the spinning bobbin may have poor strength immediately after spinning, but if left at room temperature (for example, 2
(hours to 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 heat-resistant 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.

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

(a) The organic diisocyanate used in the thermoplastic polyurethane elastomer and the polyisocyanate compound is p, p
- The composite elastic yarn according to claim 1, which is diphenylmethane diisocyanate.

(b) The bifunctional polyol component constituting the polyisocyanate compound contains at least one member selected from the group consisting of polytetramethylene glycol, polypropylene glycol, polybutylene adipate, polycaprolactone diol, and polycarbonate diol with a molecular weight of 500 to 5000. 2. The composite elastic yarn according to claim 1, which is a diol and the trifunctional polyol component is a polyester triol consisting of ε-caprolactone and trimethylolpropane.

(c) The molar ratio of the above-mentioned bifunctional polyol and trifunctional polyol component constituting the polyisocyanate compound is 97
2. The composite elastic yarn according to claim 1, wherein the composite elastic yarn has a particle diameter of /3 to 20/80.

(d) The proportion of the polyisocyanate compound in the core component is
Claim 1: The amount is 5 to 40% by weight based on the total weight of the core components.
Composite elastic yarn as described.

(e) The composite elastic yarn according to claim 1, wherein the core-sheath cross-sectional area ratio is 80/20 to 9515.

(f) The composite elastic yarn according to claim 1, wherein the adhesiveness between the core component and the sheath component is enhanced by a polyisocyanate compound in the core component.

(g) The composite elastic yarn according to claim 1, wherein the core-sheath sections are concentric or eccentric.

(Effects of the Invention) In the yarn of the present invention, the sheath component is a non-yellowing polyurethane elastomer and the core component is a crosslinked polyurethane elastomer, so it has excellent light resistance as well as thermal and mechanical properties. Very good. That is, in a preferred embodiment of the yarn of the present invention, - Light resistance: Discoloration and fading after a 40-hour irradiation test according to JIS L-0842 is grade 4 or higher.

・Heat resistance■ 190℃ recovery rate: 190℃ with the thread stretched by 30%
When placed in a hot air circulation type dryer, it does not melt and break within 1 minute, and the recovery rate when the chain yarn is relaxed to room temperature is about 3% or more. However, the recovery rate is defined as follows.

■Creep temperature: Load 10■/d, heating rate 70°C/
In the temperature-elongation creep curve below min, the temperature at 40% creep is about 150°C or higher.

- Mechanical properties: Strength is approximately 1.0 g/d or more in a tensile test according to JIS L-1013.

・Adhesion: No sticking and good unwinding properties.

・Adhesiveness of core/sheath components: Adhesion is good because the reaction occurs at the interface between the core/sheath components.

・Productivity: Advantageous for industrial production as it is obtained by melt spinning method.

It has excellent properties such as

As described above, since it has excellent not only light resistance but also heat resistance, it can be applied to, for example, fields such as socks, swimwear, foundations, and brassiere.

(Examples) The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Core component - Thermoplastic polyurethane elastomer 9855 parts of dehydrated polytetramethylene glycol with a hydroxyl value of 58.0 and 993 parts of 1,4-butanediol were placed in a jacketed kneader and thoroughly dissolved with stirring. After that, it was kept at a temperature of 85℃, and p, p'
-4152 parts of diphenylmethane diisocyanate were reacted. The obtained reaction product was taken out from the kneader and molded into pellets using an extruder. This molded body has a relative viscosity of 2.1 in dimethylformamide at 25°C.
It was 6.

■The bifunctional/trifunctional molar ratio of the polyisocyanate compound polyol component is 75/25.
9152 parts of dehydrated polybutylene adipate with a hydroxyl value of 89.4 and 1352 parts of dehydrated trifunctional polycaprolactone triol (manufactured by Dainippon Ink Industries, Ltd.: Plaxel 350) with a hydroxyl value of 3027 were placed in a polymerization pot equipped with a stirrer. The mixture was reacted with 5496 parts of p, p'-diphenylmethane diisocyanate at a temperature of 80° C. to obtain a viscous polyisocyanate compound. NCO of this thing
The content was 5.8%.

Thermoplastic non-yellowing polyurethane elastic material with a hardness of 90 “T”
-R3080'' (manufactured by Dainippon Ink Co., Ltd.) was used.

When the thermoplastic polyurethane elastomer, which is one of the components of the core component, is melted, a polyisocyanate compound is injected using a known supply device, and the core component is kneaded to form a core component using a mixing device having 15 stationary kneading elements. On the other hand, the above-mentioned sheath component is melted using an extruder to form a concentric core-sheath composite cap (
Nozzle diameter 0.5mm) and winding speed 700m/
A composite elastic yarn of 40 denier filaments was obtained in minutes.

In this case, the core-sheath cross-sectional area ratio was 92/8.

Table 1 shows the results of spinning with varying amounts of the polyisocyanate compound added to the core component. In addition, when the amount of the polyisocyanate compound in the core component was spun to 45%, there was no spinnability and it was impossible to wind up the yarn (Comparative Example 2)
.

Physical properties such as first surface yarn quality and heat resistance are values measured after a bobbin of spun urethane yarn was left at room temperature for 5 days. Note that the larger the 190° C. recovery rate and creep temperature, the better the heat resistance.

From Table 1, it can be seen that when no polyisocyanate compound is added, it melts during the measurement and cannot be measured, but by adding a polyisocyanate compound and spinning,
It can be seen that the recovery rate at 90° C. is increased, and the creep temperature is also increased, so that the heat resistance is significantly improved. On the other hand, it can be seen that the light resistance is also good.

Example 2 In Example 1, a polyisocyanate compound (NCO
The amount of 4.8%) added to the core component was fixed at 19%, the core-sheath composite ratio was fixed at 87/13, and the ratio of difunctional and trifunctional acids in the polyol component was as shown in Table 2. Spinning was carried out in the same manner as in Example 1, except that the material was changed to The results are shown in Table 2.

Claims (1)

[Claims] 1. The sheath is a thermoplastic and non-yellowing polyurethane elastomer, the core is a reaction product of a thermoplastic polyurethane elastomer and a polyisocyanate compound, and the polyisocyanate compound is a bifunctional polyurethane compound. A polymer of a polyol component, a trifunctional polyol component, and an isocyanate component, and the isocyanate NCO content in the polymer is 2 to 1.
A heat-resistant composite elastic yarn with improved light resistance, characterized in that the light resistance is in the range of 5% by weight. 2. The heat-resistant composite elastic yarn according to claim 1, which exhibits discoloration and fading of grade 4 or higher after a 40-hour irradiation test according to JISL-0842. 3. When the thread is stretched by 30% and placed in an air atmosphere at 190°C, it does not melt and break within 1 minute, and when the thread is relaxed to room temperature, the recovery rate is 3% or more. The heat-resistant composite elastic yarn according to claim 1. 4. The heat-resistant composite elastic yarn according to claim 1, wherein the temperature at 40% creep in the temperature-elongation creep curve is 130°C or higher.