JP2566902B2 - Heat resistant urethane yarn manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastic yarn, and more particularly to a method for producing a polyurethane elastic yarn having excellent heat resistance by a melt spinning method.

[0002]

2. Description of the Related Art A method for producing a polyurethane elastic yarn is roughly classified into a spinning method, a dry spinning method, a wet spinning method and a melt spinning method. Among them, the melt spinning method is advantageous as an industrial manufacturing method because it has advantages that a solvent is not required, the spinning speed is high, and the equipment is compatible.

However, since the polyurethane elastic yarn obtained by the melt spinning method uses a melt-spinnable thermoplastic polyurethane, it has problems such as poor heat resistance and insufficient recovery from deformation at high temperatures. The following methods have been proposed to solve this problem. (1) A method of adding a polyfunctional compound at the time of polymerization. (2) A method of spinning directly from a polymerization system. (3) A method in which a semi-cured polymer is melt-spun and extruded at a fixed isocyanate temperature or extruded into a curing agent. (4) A method of performing heat treatment after spinning.

[0004]

Of the methods (1), if sufficient crosslinking is applied to improve heat resistance,
Since the melting temperature of the polymer becomes high, it becomes necessary to raise the spinning temperature, which has the drawback that spinning becomes unstable.
Regarding the method (2), it is difficult to control the polymerization reaction, and 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 obtained yarn is insufficient. The methods (3) and (4) are effective in terms of heat resistance of urethane elastic yarn and recovery from deformation at high temperatures, but the processing equipment becomes large and the cost is high as an industrial manufacturing method, which is disadvantageous. Can be said to be

In addition to the above, as a method for producing a polyurethane elastic yarn which is excellent in heat resistance by the melt spinning method, we have proposed the method described in Japanese Patent Publication No. 58-46573. As a result of earnest research based on the method submitted earlier by us,
Surprisingly, the inventors have found a method for producing a polyurethane elastic yarn having further excellent heat resistance. An object of the present invention is to provide a method for producing a urethane elastic yarn having excellent heat resistance in a stable and industrially advantageous manner by a melt spinning method.

[0006]

The method for producing a heat-resistant urethane yarn according to the present invention is such that when a thermoplastic polyurethane elastic material is melt-spun, it is polymerized from a bifunctional polyol component, a trifunctional polyol component and an isocyanate component. The ratio of the number of moles of the bifunctional polyol component to be used and the number of moles of the trifunctional polyol component (use mole number ratio) is 8/2 to 5/5.
And the ratio (R ratio) of the number of moles of OH groups of the polyol component to the number of moles of NCO groups of the isocyanate component is in the range of 2 to 4 It is characterized in that it is added to and mixed with the melted polyurethane and then spun.

2 constituting the prepolymer compound of the present invention
As the functional polyol component, a diol containing at least one selected from the group consisting of polytetramethylene glycol, polypropylene glycol, polybutylene adipate, polycaprolactone diol and polycarbonate diol can be preferably used. The molecular weight of this bifunctional polyol component is 400 or more, particularly 800 to 5000.
Is preferred.

On the other hand, as the trifunctional polyol component, polyether-based triol obtained by addition polymerization of alkylene oxide (eg, ethylene oxide, propylene oxide, etc.) in the presence of an initiator such as glycerin, trimethylolpropane, hexanetriol, or ethylene is used. Polycondensation polyester triol consisting of low molecular weight diols such as glycol, diethylene glycol and neopentylene glycol, the above low molecular weight triols (trimethylolpropane etc.) and low molecular weight dibasic acids (eg adipic acid, succinic acid, maleic acid etc.) , Eg Desmophe
n 600 ... Daltolac 9 ... I manufactured by Bayer
Manufactured by CI Co., Ltd., and polycaprolactone-based polyester triol obtained by polymerizing ε-caprolactone or the like in the presence of an organic compound such as tin, lead or manganese, or a metal chelate compound by using trimethylolpropane or the like, for example, Placcel 300 series. ... Daicel Chemical Industry Co., Ltd., OD-X-2125, OD-X-2155, etc .... Dainippon Ink and Chemicals Corp. can also be used suitably. this house,
The latter polycaprolactone-based polyester triol is particularly preferable. The molecular weight of this trifunctional polyol component is preferably 300 or more. Further, the bifunctional polyol component and the trifunctional polyol component can be freely selected and used in combination.

The ratio of the number of moles of the bifunctional polyol component to the number of moles of the trifunctional polyol component (the ratio of the number of moles used) when polymerizing the prepolymer compound can be set arbitrarily, but it is 8/2.
-5/5 is preferable. If the amount of the trifunctional polyol component is too small, the heat resistance of the obtained yarn will be poor, and if the amount of the trifunctional polyol component is too large, the viscosity of the prepolymer will be high and problems will occur in operability such as handleability.

On the other hand, as the polyol in which both the bifunctional polyol component and the trifunctional polyol component exist from the initial polymerization system, a polycondensation type polyester polyol composed of the above-mentioned low molecular weight diol, triol, and dibasic acid, such as Desmophen 2200 ... Bayer, OD-
X-106, OD-X-2195, etc .... Preferred are those manufactured by Dainippon Ink and Chemicals, Inc.

As the isocyanate component constituting the prepolymer compound, tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate or a modified product thereof, isohonron diisocyanate, water-added p, p'-diphenylmethane diisocyanate is used. Etc. can be used. Diphenylmethane diisocyanate is preferred.

As a method of polymerizing a prepolymer from the above-mentioned polyol component and isocyanate component, the mixed polyol component is mixed with the molten isocyanate component so that the NCO group of the isocyanate component is in excess of the OH group of the polyol component, that is, R The reaction may be performed so that the ratio becomes 2 to 4. The ratio (R ratio) of the number of moles of NCO groups of the isocyanate component to the number of moles of OH groups of the polyol component is less than 2 1 or more (If less than 1, the number of reactants at the hydroxyl group end increases,
Even if this prepolymer is mixed into polyurethane, the cross-linking structure is small and the heat resistance does not increase.), The chain of the polyol component and the isocyanate component is too extended and the viscosity becomes high, making it difficult to handle. On the other hand, when it exceeds 4, the chain of the polyol component and the isocyanate component does not extend and the prepolymer having a short chain length increases too much, and the residual ratio of the unreacted isocyanate component also increases, and this prepolymer is mixed in the polyurethane. However, satisfactory heat resistance cannot be obtained. If defoaming becomes difficult due to an increase in the viscosity of the system during polymerization, a defoaming agent may be added to the system in advance.

The thermoplastic polyurethane elastomer used in the present invention comprises a known segmented polyurethane copolymer, and has a molecular weight of 500 to 6000 such as dihydroxypolyether, dihydroxypolyester, dihydroxypolylactone, dihydroxypolyesteramide, dihydroxy. Carbonates and block copolymers thereof, and organic diisocyanates having a molecular weight of 500 or less, such as p, p'-diphenylmethane diisocyanate, tolylene diisocyanate, hydrogenated p,
It is a polymer obtained by reacting p'-diphenylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate and the like with a chain extender such as water, hydrazine, diamine and glycol. Among these polymers, polyols such as polytetramethylene glycol or polycaprolactone diol, polycarbonate diol, polybutylene adipate, poly neopentylene adipate, polyhexamethylene adipate, polyhexamethylene / butylene adipate copolymer, polycarbonate / hexamethylene adipate copolymer A polyol containing at least one selected from the group consisting of a polymer, a polyneopentylene / hexamethylene adipate copolymer, is preferred. As the organic diisocyanate, p, p'-diphenylmethane diisocyanate is preferable. Glycol is particularly preferable as the chain extender, and 1,4-bis (β-hydroxyethoxy) benzene and 1,4 butanediol are preferable. As described above, in the present invention, a polymer synthesized without using a branching agent or a crosslinking agent is basically used as the thermoplastic polyurethane for the spinning material. Therefore, it is possible to keep the spinning temperature at a low level and suppress the thermal deterioration of polyurethane. Needless to say, a polymer containing a branched or crosslinked polymer that does not extremely raise the spinning temperature can be preferably used.

The method for synthesizing the thermoplastic polyurethane used in the present invention is a so-called prepolymer method in which a polyol and an organic diisocyanate compound are preliminarily reacted with each other and then a chain extender is reacted, or a so-called reaction material is mixed at once. Either one-shot method can be adopted. While it is possible to use solvents or diluents during polymer synthesis, bulk polymerization is more preferred for producing polymer pellets for melt spinning. As a method of bulk polymerization, a method of continuously or semi-continuously collecting a polymer using an extruder, a method of obtaining a block-like, powder-like or flake-like polymer by a batch reaction are preferably used.

In the present invention, in addition to the completely thermoplastic polyurethane which is used in the field of molding of polyurethane elastic body and the polymer synthesis reaction is sufficiently completed, a so-called incomplete thermoplastic elastomer, that is, a very small amount of isocyanate is used. It is also possible to use the pellets in which the base remains to cause crosslinking after molding. However, since such pellets have a problem that they are easily deteriorated due to moisture, temperature, etc. during storage, it is convenient to use thermoplastic polyurethane whose reaction is completed.

The addition amount of the prepolymer compound of the present invention is
It is from 15 to 40% by weight based on the mixture of the thermoplastic polyurethane elastic body used for spinning and the prepolymer compound. The addition amount varies depending on the type of polyisocyanate compound used, but if the addition amount is small, the improvement in the thermal performance of the target urethane yarn is insufficient. On the other hand, if the amount added is too large, uneven mixing or deterioration of yarn quality is likely to occur, and spinning is unstable, which is not preferable.

The melt spinning of the present invention is preferably carried out by a spinning apparatus provided with a spinning head and a portion where a prepolymer compound is added and mixed to the portion where the thermoplastic polyurethane elastic material is melt extruded. As such a spinning device, a known device used for adding a modifier during spinning can be used. It is possible to use a kneading device having a rotating part in a portion where the prepolymer compound is added to and mixed with the molten polyurethane, but more preferable is to use a mixing device having a static kneading element. is there. A known mixing device having a static kneading element can be used. The shape and number of static kneading elements differ depending on the conditions of use, but they are selected so that the polyurethane elastic body and the prepolymer compound are sufficiently mixed before being discharged from the spinneret. It is essential to do so, and usually 20 to 90 elements are provided.

An example of the embodiment of the present invention will be described below. Pellets of thermoplastic polyurethane elastic material are supplied from the hopper and heated and melted by the extruder. Melting temperature is 19
The range of 0 to 230 ° C. is preferable. On the other hand, the prepolymer compound melts in the supply tank at a temperature below 100 ° C,
Degas in advance. If the melting temperature is too high, alteration of the prepolymer compound is likely to occur. Therefore, it is preferable that the melting temperature be low, and a temperature between room temperature and 100 ° C. is appropriately used. Weigh the molten prepolymer compound with a metering pump, filter with a filter if necessary,
It is added to the melted polyurethane at the association section provided at the tip of the extruder. The prepolymer compound and polyurethane are 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 apparatus for synthetic fiber spinning can be used, but it is preferable to design the spinning head to have a shape in which the retained portion of the mixture is as small as possible. If necessary, a filter layer provided in the spinning head removes foreign substances with a filter material such as wire mesh or glass beads, and then the mixture is discharged from a spinneret, air-cooled, oiled, and then wound up. The winding speed is usually 40
0 to 1500 m / min is used. Urethane yarn wound on a spinning bobbin may be inferior in strength immediately after spinning, but while it is left at room temperature (for example, 2 hours to 6 days).
The strength is improved, and the recovery property from elongation at high temperature is also improved. Further, by performing heat treatment by an appropriate method after spinning, improvement in yarn quality and thermal performance is promoted. The quality and thermal performance of the polyurethane elastic yarn spun in this way changes with time because the reaction of the prepolymer compound mixed with the thermoplastic polyurethane elastic body used as the spinning raw material is completed during spinning. It is presumed that, without spinning, it proceeds even after spinning. This reaction is considered to be the formation of a branched or crosslinked polymer by the allophanate bond between the polyurethane and the prepolymer compound.

The preferred embodiments of the present invention will be summarized and described below. (A) The bifunctional polyol component is a diol containing at least one selected from the group consisting of polytetramethylene glycol, polypropylene glycol, polybutylene adipate, polycaprolactone diol, and polycarbonate diol. the method of. (B) The method according to claim 1, wherein the trifunctional polyol component is a polycaprolactone-based polyester triol. (C) The method according to claim 1, wherein the isocyanate component is a diisocyanate compound. (D) The method according to claim 1, wherein the bifunctional polyol component has a molecular weight of 400 or more and the trifunctional polyol component has a molecular weight of 300 or more. (E) The method according to claim 1, wherein the diisocyanate component is p, p'-diphenylmethane diisocyanate. (F) The polyol used for the thermoplastic polyurethane elastic material has a number average molecular weight of 500 to 6000, such as polytetramethylene glycol or polycaprolactone diol, polycarbonate diol, polybutylene adipate, poly neopentylene adipate, polyhexamethylene adipate, poly At least one selected from the group consisting of hexamethylene / butylene adipate copolymer, polycarbonate / hexamethylene adipate copolymer, and polyneopentylene / hexamethylene adipate copolymer.
The method of claim 1 which is a polyol containing a seed. (G) The method according to claim 1, wherein the chain extender used for the thermoplastic polyurethane elastic material is glycol or triol having a molecular weight of 500 or less. (H) The method according to claim 1, wherein the organic diisocyanate used for the thermoplastic polyurethane elastic material is p, p'-diphenylmethane diisocyanate. The method according to claim 1, wherein the addition amount of (i) the prepolymer compound is 15 to 40% by weight based on the mixture of the thermoplastic polyurethane elastic body and the prepolymer compound. The method according to claim 1, wherein the mixing is carried out in an apparatus equipped with a static kneading element.

[0020]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. Examples 1 to 4, Comparative Example 1 The ratio of the number of moles of the bifunctional and trifunctional polyol components (the number of moles used) is 8/2, and the number of moles of OH groups of the polyol component and the number of moles of NCO groups of the isocyanate component are Ratio (R ratio) of 2.4, dehydrated hydroxyl value 89.7 (mg
・ KOH / g) bifunctional polycaprolactone diol 4
8.6 parts (mol number = 0.0389, OH group mol number = 0.
0778) and a hydroxyl value of 84.6 (mg · KOH / g) trifunctional polycaprolactone triol (Placcel 320 manufactured by Daicel Chemical Industries) 19.3 parts (mol number = 0.0)
097, OH group mol number = 0.0292) was dissolved in a polymerization kettle equipped with a stirrer at a temperature of 80 ° C to obtain 32.1 parts of p, p'-diphenylmethane diisocyanate (mol number =
0.1284, mol number of NCO group = 0.2568) and reacted for about 80 minutes to obtain a viscous prepolymer compound. Further, a vacuum was applied to this compound to perform a defoaming operation.

On the other hand, 63.4 parts of dehydrated polyhexamethylene adipate diol having a hydroxyl value of 56.1 and 1,4
-Butanediol (6.2 parts) was charged into a kneader equipped with a jacket, dissolved sufficiently while stirring, and then maintained at a temperature of 85 ° C, and 26.4 parts of p, p'-diphenylmethane diisocyanate was added and reacted. . The obtained reaction product was taken out from the kneader and molded into pellets by an extruder. This molded product had a relative viscosity of 2.30 in dimethylformamide at 25 ° C.

A kneading device having a prepolymer compound feeding device and a static kneading element 60 element (Kenix static mixer) using the pellets of the thermoplastic polyurethane elastic body thus obtained and the prepolymer compound as spinning raw materials. Melt spinning was performed by a spinning machine equipped with and. A 40 denier filament was spun at a winding speed of 500 m / min using a nozzle having a diameter of 0.5φ as a spinneret. Table 1 shows the results of spinning while changing the amount of the prepolymer compound added to the urethane yarn. The numerical relationships of the prepolymers of Example 1 are summarized in Table 2 in order to clarify the content of the present invention.

[0023]

[Table 1]

[0024]

[Table 2]

The yarn quality and heat set recovery rate in Table 1 are values measured after the bobbin of the spun urethane yarn was left at room temperature for 5 days. The heat set recovery rate at 190 ° C. is the recovery rate when heat-treating a 30% stretched urethane yarn at 190 ° C. for 1 minute. From Table 1, when the prepolymer compound is not added, it cannot be measured because it melts during the measurement, but by adding the prepolymer compound and spinning, the heat set recovery rate becomes large, and therefore the heat resistance is improved. I understand that

Examples 5 to 9 and Comparative Examples 2 to 4 Using the same thermoplastic polyurethane elastic body as in Example 1,
For the prepolymer compound, the molar ratio of the two polyol components used and the R ratio including the isocyanate component are shown in Table 3.
The spinning was carried out in the same manner as in Example 1 except that the above was changed. The amount of prepolymer added was fixed at 18%.

[0027]

[Table 3]

It can be seen from Table 3 that when the amount of the trifunctional polyol added is increased, the heat set recovery rate is large and the heat resistance is improved, but the recovery rate is small when the trifunctional polyol is 0%. Further, when the R ratio was 1.8, the viscosity of the obtained prepolymer was high and it was difficult to handle it in the subsequent steps. On the contrary, when the R ratio was 4.2, the heat resistance decreased.

From the point of view of practicality, the above is summarized as follows: (1) The fabric knitted with the yarn to which the prepolymer compound is not added as in Comparative Example 1 is commonly used in the stocking processing step from 125 to 130. When stretched at a temperature of ℃, the fabric was sagging, resulting in a fabric with no elasticity and poor quality and physical properties. At a processing temperature of 180 to 190 ° C., which is commonly used for swimsuits and foundations, thread breakage occurred and it was completely impractical. (2) The fabric knitted with the yarn (heat set recovery rate at 190 ° C. = 27%) made by using only the bifunctional polyol as the polyol component for the prepolymer as shown in Comparative Example 2 125 commonly used in processing
At a temperature of up to 130 ° C., there was no settling of the fabric due to heat during processing, and a good product with the original elasticity of the urethane yarn was obtained. However, 180-1 used for swimwear and foundation applications that require extremely high dimensional stability
When this fabric was exposed to a high processing temperature of 90 ° C., the fabric had a large settling, was not elastic, and had poor quality and physical properties. (3) A fabric knitted with a polyurethane yarn (in the case of Example 1, a heat set recovery rate at 190 ° C. = 30%) to which a prepolymer using both the bifunctional and trifunctional polyol components of the present invention is added, Even when it is used for clothing and foundation applications that require a high degree of dimensional stability, it is
A product that withstands high temperatures of 0 to 190 ° C and has excellent elasticity even after processing was obtained.

[0030]

INDUSTRIAL APPLICABILITY The yarn obtained by the present invention is not only advantageous as an industrial production method as compared with other spinning methods (for example, dry spinning method), but also excellent in heat resistance because it is produced by the melt spinning method. Therefore, it can be applied to various applications, such as socks, swimwear, foundations, and other fields where heat resistance is particularly required.

Claims (1)

(57) [Claims] 1. When melt-spinning a thermoplastic polyurethane elastic yarn, it is polymerized from a bifunctional polyol component, a trifunctional polyol component and an isocyanate component, and the number of moles of the bifunctional polyol component and the trifunctional polyol component used at that time are polymerized. Mole ratio of Is in the range of 8/2 to 5/5, and the ratio of the number of moles of OH groups contained in the polyol component to the number of moles of NCO groups contained in the isocyanate component. A method for producing a heat-resistant urethane yarn, which comprises adding 15 to 40% by weight of a prepolymer compound having a ratio of 2 to 4 to a melted polyurethane and mixing and spinning the mixture.