KR100327913B1 - Process for preparing a elastic polyurethane mono filament yarn - Google Patents

Abstract

The present invention relates to a polyester polyol condensation-polymerized using a 4,4'-diphenylmethane diisocyanate compound, adipic acid and 3-methylpentane diol such that the weight average molecular weight is 1,500 to 2,000 g / mol, and bishydroxyethyl Polyurethane polymerized using benzene and then condensation-polymerized with 4,4'-diphenylmethane diisocyanate compound, adipic acid and 3-methylpentane diol to have a weight average molecular weight of 1,500 to 2,000 g / mol. A process for producing polyurethane mono-elastic yarn using ester polyol as a crosslinking agent and adding and mixing 15-25% of the crosslinking agent in a weight ratio to the melted polyurethane during melt spinning.

The present invention has the advantage of producing a polyurethane mono-elastic yarn with good heat radiation and excellent heat resistance and elastic recovery rate.

Description

Process for preparing a elastic polyurethane mono filament yarn

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

Polyurethane-based elastic yarns are excellent in elasticity and elastic recovery power has been widely used in stretch fabrics, such as stockings, women's underwear and swimwear.

The production of polyurethane elastic yarns includes wet spinning, dry spinning, melt spinning, and a polymerization reaction spinning method which is a unique method.

These methods have their own characteristics, but from an economical and industrial point of view, the melt spinning method is more advantageous than the other methods in consideration of the flexibility of the device, the compatibility and the simplicity of the spinning method. .

However, polyurethane-based elastic yarn is poor in heat resistance, so when mixed with other materials such as polyester fiber, when dyed at a high temperature at 130 ℃, physical properties such as elastic recovery power and strength is lowered, which leads to a lot of restrictions on the use.

Generally, elastic yarns produced by the dry method, the wet method, or the polymerization spinning method contain urethane and urea groups at the same time, and thus have excellent elastic recovery at high temperatures.

However, in the case of containing a urea group, since the melt spinning is not possible because it is not melted due to the physical secondary bonding of the urea period, there is no choice but to manufacture elastic yarns using a spinning method using a solvent.

Therefore, because this method uses a solvent, the spinning method is difficult and the investment cost for manufacturing equipment is high.

The manufacturing method of the elastic yarn by the melt spinning method is very advantageous from an industrial point of view because it does not use a solvent and the spinning method is simple.

However, polyurethane elastic yarns composed of polyurethane groups alone are not suitable for use at high temperatures because of their low thermal stability.

Conventional methods for improving the heat resistance of polyurethane elastic yarns include a polyol having three hydroxyl groups and mixing them with a polyol having two hydroxyl groups to polymerize the prepolymer, followed by a chain extension reaction using a chain extender having two hydroxyl groups. There is a method of obtaining a partially crosslinked polyurethane by melt spinning and melt spinning it (Japanese Patent Laid-Open No. 49-48677).

Another method is to obtain a partially crosslinked polyurethane using a polyol having three hydroxyl groups or a chain extender after prepolymer polymerization, and then melt spun it (Japanese Patent Application Laid-Open No. 43-7426, Japanese Patent Laid-Open). 7-70278).

Among the conventional methods described above, a method of introducing a chemical crosslink into a polyurethane using an organic compound having three hydroxyl groups has disadvantages in that the melt state is uneven during spinning and the melt viscosity becomes very high.

If the molten state is uneven, the uniformity of the spun yarn is reduced and workability is reduced.

In addition, when the melt viscosity is increased, the spinning temperature should be increased, but if the spinning temperature is raised to 240 ° C. or more, thermal decomposition of the polyurethane may occur, resulting in a decrease in molecular weight, thereby deteriorating final physical properties.

Another method of introducing a chemical crosslink into a polyurethane without using an organic compound having three hydroxyl groups is to form an intermediate polymer having terminal ends of isocyanate, and then using terminal treatment agents such as diol or diamine. The intermediate polymer is treated to treat residual isocyanate groups.

Method of producing a crosslinked polyurethane elastic yarn by melt spinning the treated intermediate polymer with a molten ejector to form a filament, then passing through a crosslinking treatment bath having a swelling agent and a crosslinking agent, and then performing a crosslinking reaction by heat treatment in a stream of nitrogen. There is (Japanese Patent Laid-Open No. 42-19499).

The method presented above is cumbersome in that the intermediate polymer is treated with an end treatment and then precipitated in water and the precipitated intermediate polymer is separated separately.

In addition, the method of passing the spun polyurethane filament through the crosslinking agent treatment bath has a very complicated device, and since the solvent is used as a swelling agent in the crosslinker treatment bath, the solvent must be removed later.

In addition, since the crosslinking agent is mainly present on the surface of the filament, the crosslinking reaction between the filaments proceeds by the reaction between the crosslinking agents present on the surface of the filament, so that the dissolution property of the filament after winding is poor.

The present invention mainly comprises allophanate groups through a method of crosslinking reaction in a polyurethane filament by adding and mixing an intermediate polymer having an isocyanate group as a crosslinking agent to a melt-extruding polyurethane and radioactive and An object of the present invention is to provide a method for producing a polyurethane monoelastic yarn having excellent heat resistance.

In the present invention, a polyester polyol is reacted with a diisocyanate to obtain a polyurethane intermediate polymer, and then a chain extension reaction is performed using an alkane diol compound as a chain extender to prepare a polyurethane.

In addition, the polyester polyol is reacted with diisocyanate to obtain an intermediate polymer having an isocyanate group, which is used as a crosslinking agent.

By adding and mixing the crosslinking agent to the melted polyurethane during melt spinning, an allophanate group is mainly used to obtain a polyurethane monoelastic yarn having excellent spinning and heat resistance.

In more detail, the present invention is prepared by reacting 1 mol of a linear high molecular weight diol compound having a weight average molecular weight of 1,500 to 2,500 g / mol with 2 mol of an aliphatic or aromatic diisocyanate compound to obtain a prepolymer having an isocyanate terminal. Aliphatic or aromatic or alicyclic diols or mixtures of these compounds having a weight average molecular weight of 400 or less are added to the intermediate polymer, and 1 mole of hydroxyl groups are added to the prepolymer relative to the isocyanate group of the prepolymer until the viscosity of the polymerization system reaches equilibrium. To produce a high molecular weight polyurethane polymer.

The polyurethane polymer thus obtained is made into chips of uniform size using a pelletizer.

After reacting 1 mol of a linear high molecular weight diol compound having a weight average molecular weight of 1,500 to 2,500 g / mol with 2 mol of an aliphatic or aromatic diisocyanate compound to obtain a prepolymer having an isocyanate terminal, the high molecular weight polyurethane polymer obtained above was prepared. In the process of melt spinning, a predetermined amount of mixed prepolymer whose end is isocyanate is mixed, followed by melt spinning, followed by heat treatment at 90 ° C. for 24 hours to prepare allophanate group, and to prepare polyurethane elastic yarn having excellent heat resistance. .

In the present invention, the amount of the crosslinking agent added is preferably 15 to 25% by weight based on the polyurethane polymer.

If the amount of the crosslinking agent is less than 15%, the degree of improvement of heat resistance is insignificant, and if the amount of the crosslinking agent is more than 25%, the melt viscosity is too low to wind up and the nozzle needs to be frequently replaced.

As the diisocyanate compound used in the present invention, p-phenylene diisocyanate, m-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,4-tetramethylene diisocyanate, 1,10 Compounds such as decamethane diisocyanate, 1,5-tetrahydroxy naphthalene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-diphenylene diisocyanate, 4,4'-diphenylmethane diisocyanate Among these compounds, 4,4'-diphenylmethane diisocyanate compound is most preferable in consideration of the reactivity with the diol compound and the physical properties of the elastomer.

There are two kinds of polyols used in the present invention, polyether polyols having a weight average molecular weight of 1,500 to 2,500 g / mol and polyester polyols.

Polyether polyols include polyethylene oxide glycol, polypropylene oxide, polytetramethylene oxide glycol, polypentamethylene oxide glycol, polyhexamethylene oxide glycol, polyheptamethylene oxide glycol, polyoctamethylene oxide glycol, polynanomethylene oxide glycol and poly Decamethylene oxide glycol or glycol mixtures or copolymers thereof, and the like.

Examples of the linear polyester polyol having a hydroxyl group at the terminal include glycol components such as ethylene glycol, propylene glycol, butanediol, 3-methylpentanediol, hexanediol and bisoxymethyl cyclohexane, and acid components such as adipic acid, terephthalic acid and isophthalic acid. It is a polyester produced by condensation polymerization.

In the case of producing an intermediate polymer containing a polyurethane bond, any of the above polyether type or polyester type may be used as the hydroxyl group material, or a mixed or copolymer type of dimer may be used.

Pyrolysis of polyether polyols occurs because the polyether polyols, diisocyanates and polyurethanes polymerized with diol chain extenders have to be spun at temperatures of 200 ° C. or higher.

As a result, the molecular weight and the heat resistance of the final elastic yarn are lowered because the molecular weight of the wound elastic yarn is lowered.

Therefore, in the present invention, polyester polyol was used in consideration of physical properties, heat resistance, radioactivity, etc. of the final polyurethane filament to minimize molecular weight decrease due to thermal decomposition of the polyether polyol.

The polyester polyol is a polyester polyol condensation-polymerized at a weight average molecular weight of 1,500 to 2,500 g / mol using adipic acid and 1,4-butanediol.

Prepolymers in which a high molecular weight diol compound and a diisocyanate compound are combined can obtain a polymer having an appropriate molecular weight by using a low molecular weight diamine and a diol compound as a chain extender. When the diamine compound is used as a chain extender, the chain-extended polymer is subjected to heat. Since it is not melted by the melt spinning method, it is impossible to manufacture the elastic yarn.

Therefore, as mentioned above, the polymer using the diamine chain extender can produce elastic yarn by dry spinning or wet spinning.

However, since the melting temperature of the polymer obtained by using the diol compound as the chain extender is 200 ° C. or lower, the elastic yarn can be produced by the melt spinning method.

Diol compounds used as chain extenders include ethylene glycol, propylene glycol, butanediol, pentanediol, 3-methylpentanediol, hexanediol, bishydroxy ethylbenzene, and the like. Bishydroxy ethylbenzene was used in consideration of physical properties and heat resistance.

Since bishydroxy ethylbenzene contains a benzene ring, the molecular chain is rigid compared to the aliphatic diol compound, which is advantageous in terms of improving physical properties and heat resistance.

The prepolymer used as the crosslinking agent in the present invention can be prepared by the reaction of the diisocyanate group with the polyol, considering the compatibility with the polyurethane to prepare a crosslinking agent using a polyester polyol.

As the polyol, various polyols mentioned above may be used, but in the present invention, a polyester polyol condensation-polymerized at 1,500 to 2,500 g / mol using adipic acid and 3-methylpentanediol was used.

As the diisocyanate used as the crosslinking agent in the present invention, it is most preferable to use a 4,4'-diphenylmethane diisocyanate compound in consideration of compatibility with, and reactivity with, polyurethane.

The present invention will be described in more detail. First, 2 moles of the diisocyanate compound and 1 mole of polyester polyol are mixed, and then the temperature of the reaction system is raised to 80 ° C. until the viscosity of the polymerization system reaches equilibrium.

After completion of the first reaction, the temperature of the reaction system is lowered to room temperature, and a diol chain extender is gradually added.

After addition of the diol chain extender, the temperature of the reaction system is raised to 200 ° C.

After the secondary reaction proceeds until the viscosity of the reaction system reaches the equilibrium, the polymer is brought into a chip state by using a pelletizer.

The crosslinking agent is first mixed with 2 moles of the diisocyanate compound and 1 mole of polyester polyol, and then the temperature of the reaction system is raised to 80 ° C. until the viscosity of the polymerization system reaches equilibrium.

After completion of the reaction, the temperature of the reaction system is lowered to room temperature and stored under a cool dark nitrogen stream.

After drying the polymerized polyurethane chip for 12 hours at 100 ° C. under a nitrogen stream, the polyurethane was melted in a melt injection molding machine, and then the prepolymer used as a crosslinking agent was added and mixed with the melted polyurethane, followed by spinning by melt spinning. By heat-treating at 90 ° C. for 24 hours in a nitrogen gas atmosphere, an allopinate group is mainly used to prepare a polyurethane elastic yarn having excellent radioactivity, physical properties, and heat resistance.

Polyurethane elastic yarn of 30 denier was prepared by the above method, and various physical properties and heat resistance were measured.

Tensile strength, elongation, and elastic recovery rate shown in the Examples were evaluated according to KSK 0219, and the heat resistance was evaluated as a heat-resistant temperature by maintaining the temperature at 30% elongation for 1 minute at a temperature of 40% or more.

The degradability was evaluated by measuring the tension to dissolve the wound polyurethane elastic yarn at a rate of 250 times per minute.

Example 1

To 500 g of 4,4'-diphenylmethane diisocyanate compound, 900 g of a polyester polyol condensation-polymerized using adipic acid and 3-methylpentanediol to have a weight average molecular weight of 1,800 g / mol was added, and then the temperature was raised to 80 ° C. The mixture was heated to react until the viscosity of the reaction system reached equilibrium, thereby preparing an interpolymer having an isocyanate terminal.

After the temperature of the prepolymer was lowered to room temperature, 166 g of bishydroxy ethylbenzene was slowly added to the prepolymer at a rate of 5 g / min and mixed.

After the addition of bishydroxy ethylbenzene, the temperature of the reaction system was raised to 200 ° C., and the secondary reaction was carried out until the viscosity of the reaction system reached equilibrium, thereby polymerizing a high molecular weight polyurethane, and then using a pelletizer Is made into a uniform chip.

The crosslinking agent was first mixed with 250 g of 4,4'-diphenylmethane diisocyanate compound and 900 g of polyester polyol condensation-polymerized at 1,800 g / mol by weight of adipic acid and 3-methylpentane diol, and then The temperature is raised to 80 ° C. and reacted until the viscosity of the polymerization system reaches equilibrium.

After completion of the reaction, the temperature of the reaction system is lowered to room temperature and stored under a cool dark nitrogen stream.

The polyurethane chip obtained by the above method was dried at 100 ° C. under nitrogen stream for 12 hours, and then the polyurethane was melted in the melt injection machine. Then, 15% of the prepolymer used as a crosslinking agent was added to the melted polyurethane in a weight ratio. After spinning by melt spinning method to prepare 30 denier polyurethane elastic yarn, heat treatment for 24 hours at 80 ℃ under nitrogen gas atmosphere mainly made of allophanate group, polyurethane elastic yarn with excellent radioactivity, physical properties and heat resistance Was prepared, and the physical properties and heat resistance measurement results are shown in Table 1.

Comparative Example 1

A polyurethane elastic yarn was prepared in the same manner as in Example 1 except that the crosslinking agent was added 8%. The physical properties and the heat resistance measurement results are shown in Table 1.

Comparative Example 2

A polyurethane elastic yarn was prepared in the same manner as in Example 1 except that the crosslinking agent was added 26%. The physical properties and the heat resistance measurement results are shown in Table 1.

Comparative Example 3

Polyurethane elastic yarns were prepared in the same manner as in Example 1 except that the crosslinking agent was prepared using polytetramethylene glycol, and physical properties and heat resistance measurement results are shown in Table 1.

Comparative Example 4

Except for using 1,4-butanediol without using bishydroxy ethylbenzene in the diol compound that is a chain extender during the polyurethane polymerization, and the same as in Example 1, the physical properties and heat resistance measurement results are shown in Table 1.

Comparative Example 5

Except that a crosslinking agent was prepared using a 2,4-toluene diisocyanate compound instead of 4,4'-diphenylmethane diisocyanate as a diisocyanate compound, it was the same as in Example 1, and the physical properties and heat resistance measurement results are shown in Table 1. .

<Table 1>

Tensile strength (g / d) Elongation (%) Elastic recovery rate (%) Heat resistance temperature (℃) Radioactive Maritime Example 1 1.55 610 96 190 ◎ ◎ Comparative Example 1 1.24 580 85 150 ◎ ◎ Comparative Example 2 1.68 650 96 200 × △ Comparative Example 3 1.35 580 95 170 △ × Comparative Example 4 1.43 620 94 180 ◎ ○ Comparative Example 5 1.38 560 91 160 ○ ○

◎: very good, ○: good, △: normal, ×: bad

According to the present invention, a polyurethane mono-elastic yarn having a high elastic recovery rate, a high heat resistance temperature and excellent disintegration properties can be produced by using a melt spinning method with a simple manufacturing process.

Claims (4)

A 4,4'-diphenylmethane diisocyanate compound, a polyester polyol obtained by condensation of adipic acid and 3-methylpentanediol, and bis hydroxyethylbenzene were polymerized to make a polyurethane, and a 4,4'- It is prepared by polymerizing a diphenyl methane diisocyanate compound and a polyester polyol obtained by condensation polymerization of adipic acid and 3-methylpentanediol to form a crosslinking agent, and then adding and mixing the crosslinking agent to the polyurethane melt, followed by melt spinning. Polyurethane monoelastic yarn production method characterized in that. The method according to claim 1, wherein the polyester polyol used for polyurethane polymerization has a weight average molecular weight of 1,500 to 2,500 g / mol. The method according to claim 1, wherein the polyester polyol used at the time of polymerization of the crosslinking agent has a weight average molecular weight of 1,500 to 2,500 g / mol. The method according to claim 1, wherein the amount of the crosslinking agent added is 15 to 25% of the total weight of the polyurethane.