CN1274770A - Manufacturing method of high performance polyurethane elastic fiber - Google Patents

Abstract

The invention relates to a method for preparing high-performance polyurethane elastic fiber, which comprises polymerizing a special formula by a double screw extruder to prepare a high-performance polyurethane elastomer, drying and carrying out solid state polymerization to reach the melt spinning standard, and carrying out melt spinning to obtain the elastic fiber.

Description

Manufacturing method of high performance polyurethane elastic fiber

The invention is a method for producing polyurethane elastomers and elastic fibers suitable for melt spinning, especially a method for continuously producing polyurethane elastomers with special formulas, which can make the produced elastomers suitable for melt spinning Manufacturing process, so that the elastic fiber produced has better hydrolysis resistance, heat resistance and weather resistance than ordinary polyurethane fiber. It belongs to the technical field of man-made fibers.

Polyurethane Elastomer (PU) is the most widely used thermoplastic elastomer, generally known as TPU, which has both the thermoplastic processing properties of plastic materials and the elasticity of rubber materials, so it is widely used in Injection molding, extrusion molding, compression molding, blow molding and other processing, its products include various pipe fittings, parts, sports equipment, electronic parts and fiber products.

At present, the traditional elastic fiber, the most famous one is the dry process of DuPont Company. These methods must first synthesize polyurethane elastomer, then make it into a solution, squeeze it out of the spinneret, and then blow it away with heated nitrogen. Solvent, leaving the elastic body to form elastic fibers, this method is harmful to the human body and the environment because it involves the volatilization of solvents [such as: dimethylformamide (DMF) or dimethylacetamide (DMAC)] Cause harm, make it need to invest huge funds to carry out the recovery of solvent, cause the elastic fiber cost that utilizes this kind of method to be too high, be unfavorable for popularization and application and competition in the market.

In recent years, the technology of producing elastic fiber by melt spinning has been developed in Japan. It is different from DuPont's dry production method. The elastic fiber production process using the melt method does not have the problem of solvent recovery, which can make the production cost lower. Low, but due to the poor heat resistance of general polyurethane elastomers, their physical properties will be greatly reduced after high-temperature melt spinning, and the elastic fibers made will also be heated, dyed and finished in the subsequent processing procedures Such steps must accept changes such as high temperature and hydrolysis, which makes the melt spinning method developed by Japan subject to many restrictions in use, and its physical and chemical properties are lower than those produced by DuPont's dry method. spandex.

The main purpose of the present invention is to provide a continuous process for producing high-performance polyurethane elastic fibers, which is to carry out pre-polymerization in a reaction tank, and then use a twin-screw extruder to process the pre-polymer and chain extender. And additives, etc., are reacted and extruded, and water, unreacted substances and low polymers are removed by high vacuum. The product is pelletized through the outlet of the twin-screw extruder, and the completed polyurethane elastomer can be used after drying. Carry out the processing operation of melt spinning.

The invention discloses a method for producing high-performance polyurethane elastic fiber, wherein the formula used in the production of polyurethane elastomer is to carry out pre-polymerization reaction with polyester diol and diisocyanate, and then combine the pre-polymerization reaction product with chain extension The agent is fed into the twin-screw extruder by a metering gear pump for reaction and extrusion to produce a polyurethane elastomer with high-performance physical and chemical properties, so as to make polyurethane elastic fiber by melt spinning.

Among them, the polyester diol system is used in combination of A and B;

The ingredients of category A are poly(tetramethylene adipate)glycol or poly(ε-caprolactone)glycol;

The components of class B are polyester diols produced by the reaction of high-purity 36-carbon dimer acid and diol; the molecular weight of polyester diols of class A and B is 500g/mole-3000g/mole, of which The chemical structure of the 36-carbon dimer acid of type B polyester diol is:

The present invention adopts two kinds of polyester diols of A and B to be mixed and used, and the molar ratio of mixing is 95:5～5:95.

Wherein, the temperature of the pre-polymerization reaction is 60-80° C., the reaction time is 0.5-2 hours, and nitrogen gas is filled into the pre-polymerization reaction tank during the reaction.

The formula ratio is roughly:

Polyester diol: chain extender: MDI = 1:1:2～1:10:11; the principle is that the number of moles of polyester diol + chain extender is equal to the mole of MDI (diisocyanate) ear count.

The chain extenders are diols, which can be divided into two parts, A and B;

Part A is 1.4-butanediol, 1.6-hexanediol or 1.2-ethanediol,

Part B is an aromatic binary group, and its chemical structure is:

Its m, n are integers 1, 2, 3, 4, 5, and m+n=2-10.

Wherein, the mixing molar ratio of A and B diols used in combination is 95:5˜5:95.

The drying temperature of the polyurethane elastomer is usually heated to 70-100°C with dew point -60°C absolute dry air for drying.

The advantage of the present invention is: the present invention uses multiple materials and process settings to effectively improve the general formula for producing polyurethane elasticity. The characteristics of the formula and process are as follows:

1. Polyurethane soft segment partly made of polyester diol, which is made by reacting high-purity 36-carbon dimer acid with diol, can improve the heat resistance and hydrolysis resistance of the elastomer.

2. Diols composed of aromatic structures are used as chain extenders for polyurethanes, which can increase the heat resistance and melting point of elastomers.

3. Polyurethane elastomer is produced by continuous twin-screw reaction extrusion, and the ratio of hard segment to soft segment can be adjusted arbitrarily, so that the quality of the product is stable.

4. Melt-spinning according to the specially formulated elastomer can have excellent heat resistance, hydrolysis resistance and weather resistance.

The present invention uses a unique formula to produce high-performance polyurethane elastomers, and further applies the polyurethane elastomers to the production of elastic fibers. The process used is simple and the product properties are stable; especially its unique formula can produce Excellent innovation effect.

The present invention has the following drawings:

Fig. 1 is the manufacturing flow chart of the relevant polyurethane elastomer of the present invention.

Fig. 2 is a schematic diagram of the manufacturing equipment of the polyurethane elastomer related to the present invention.

Fig. 3 is a flow chart of the manufacture of polyurethane elastic fibers related to the present invention.

Fig. 4 is a schematic diagram of the manufacturing equipment of the polyurethane elastic fiber related to the present invention.

The numbers in the figure are as follows:

1. Diisocyanate preheating tank 2. Polyester diol preheating tank

3. Additive preheating tank 4. Prepolymerization reaction tank

5. Pre-polymer intermediate tank 6. Chain extender preheating tank

7. Middle tank of chain extender 8. Metering gear pump

9. Metering gear pump 10. Metering gear pump

11. Metering gear pump 12. Metering gear pump

13. Raw material export 14. Twin-screw extruder

15. Vacuum extraction outlet 16. Cooling water tank

17. Granulator 18. Elastomer drying tank

19. Elastic body middle groove 20. Extrusion machine

21. Spinning group 22. Cooling bellows

23. Spinning tube 24. The first intermediate wheel

25. Second intermediate wheel 26. Coiler

Hereby give preferred embodiment and cooperate accompanying drawing to describe in detail as follows:

The present invention is a kind of manufacturing method about polyurethane elastomer and elastic fiber, please refer to each accompanying drawing, and the manufacturing process of the present invention will be explained item by item:

A: Diisocyanate preheating

Please refer to Fig. 2, shown in Fig. 2, the diisocyanate (diisocyanate) composition that the present invention adopts is Methylene bis-(phenylisocynate), is called for short MDI, and its purity is about 97%, and fusing point is 42-44 ℃, and general department preserves In the freezer below 0°C, in order to ensure its safety, MDI needs to be dissolved in the diisocyanate preheating tank 1 at 50°C during use, but the temperature during dissolution should not be higher than 65°C, and at the same time The retention time of its molten state should not exceed one hour, so as to prevent the polymerization reaction of MDI itself.

B: Polyester diol is heated and vacuumed to remove water

The polyester glycol that the present invention adopts can be divided into A, B two kinds; Wherein, the composition of A class is poly (tetramethylene adipate) glycol or poly (ε-caprolactone) glycol; Polyester diol produced by the reaction of carbon dimer acid and diol; A and B types of polyester diols have a molecular weight of 500g/mole-3000g/mole, of which B type has a 36-carbon structure, which can provide Elastomer high and low temperature stability, hydrolysis resistance, weather resistance and oxidation stability.

Among them, the chemical structure of the 36-carbon diester is:

The present invention adopts two types of polyester diols A and B to be mixed, and the molar ratio of the mixture is 95:5 to 5:95, which can be selected according to the needs of customers, because polyester diols often absorb moisture , so before use, it is necessary to preheat the water removal tank 2 to dissolve the polyester diol. It needs to be heated to above 100°C, and the absorbed water should be removed by vacuum for use.

C: additive preheating

In order to make the reaction progress quickly, the present invention achieves the goal quickly and stabilizes the properties of the product in the future. In particular, catalysts, heat stabilizers and antioxidants are added to the reactants, and the required reactants are all dissolved in the additive preheating tank 3 for later use. .

D: Prepolymerization

The diisocyanates, polyester diols and additives used in the present invention are metered into the pre-polymerization reaction tank 4 through a metering gear pump to carry out pre-polymerization. 0.5 to 2 hours. During the reaction, nitrogen gas is used to fill the pre-polymerization tank 4 to prevent oxidation.

E: Pre-polymer middle tank

The prepolymer polymerized through the prepolymerization reaction is sent to the polymer intermediate tank 5 at one time, and the prepolymerization reaction tank 4 can carry out another batch of reactions.

F: chain extender preheating

The chain extender that the present invention adopts is diols, can be divided into A, B two parts; A part is 1.4-butanediol, 1.6-hexanediol or 1.2-ethylene glycol, and the chemical structure of B part is:

Its m, n are integers 1, 2, 3, 4, 5, and the structure of m+n=2~10B part is an aromatic binary group, which provides excellent heat resistance properties of the polymer. This polymerization reaction adopts A and B Two kinds of diols are used in mixture, one of which is selected from A and B, and the molar ratio is 95:5~5:95, which can be selected according to customer needs. The diol needs to be placed in the chain extender preheating tank 6 Heat in medium to mix evenly, and raise the temperature to 80°C for later use.

G: chain extender middle tank

The chain extender mixed evenly with the chain extender is transferred to the chain extender intermediate tank 7 for standby, while the chain extender preheating tank 6 can be prepared for the next batch.

H: Twin-screw extruder setting

The present invention adopts a continuous polymerization reaction, and the control of the product properties is completely in accordance with the pre-calculated ratio, and the required raw materials are measured and reacted, for example: the molar ratio of MDI and polyester diol in the pre-polymerization reaction or the pre-polymer and The molar ratio of the chain extender can be precisely controlled by metering gear pumps 8, 9, 10, 11, 12.

The formula ratio that the present invention adopts is roughly:

Polyester diol: chain extender: MDI = 1:1:2～1:10:11; the molar ratio is used above, and the principle is that the molar number of polyester diol + chain extender is equal to that of MDI However, in order to achieve high molecular weight, the molar error caused by each metering gear pump 8, 9, 10, 11, and 12 must not exceed 1%, otherwise it will cause low molecular weight and poor quality.

The reactants in the middle tank of the above E and G steps are sent to the raw material inlet 13 of the twin-screw extruder 14 through a precise metering gear pump, and the temperature of the twin-screw extruder 14 is set to There are slight differences depending on different formulations. The temperature setting range is 170-240°C. The time required for the reaction and extrusion can be controlled by the screw speed. The reaction time for the extrusion of the reactants is 1 to 10 minutes. The gas (carbon dioxide or water vapor) and small molecular weight non-reactive substances produced during the process can be extracted from the vacuum extraction outlet 15, so that the product can be perfectly bubble-free, and sent out from the twin-screw extruder 14 outlet.

I: Elastomer is extruded and cooled to pelletize

In the present invention, the product sent out from the twin-screw extruder 14 is rapidly cooled by the cooling water tank 16, and pelletized by the pelletizer 17, so that polyurethane elastomer products with unique formula and excellent physical and chemical properties can be produced.

J: Elastomer dry

Please refer to Figure 3 and Figure 4. Since the glass transition point of polyurethane elastomer is lower than room temperature, the drying temperature should not be set too high. Usually, it is carried out by heating to 70-100°C with absolutely dry air with a dew point of -60°C. Drying, when the dry hot air passes through the polyurethane elastomer, the polyurethane elastomer can be stirred by the agitator in the elastomer drying tank 18, so that the dry hot air can quickly take away the moisture, and at the same time, after 4 to 20 hours of continuous drying, Polyurethane elastomer can undergo solid-state polymerization reaction, so that the molecular weight of polyurethane elastomer can reach the standard of melt spinning.

K: Extruder setting

According to the difference in the composition of polyurethane elastomers, the melting point of polyurethane elastomers is 165-200°C, so the temperature of the extruder 20 is set at 190-230°C, the pressure is set at 50-200kg/cm, and the speed is set at 2-50rpm , set according to the spinning specifications, and the residence time of the polyurethane elastomer in the extruder 20 is preferably no more than 15 minutes, and the best situation is no more than 5 minutes, which can prevent the cracking reaction of the polyurethane elastomer at high temperature .

L: spinning path setting

The length of the spinning path can be adjusted as required, but the cooling air temperature of the required cooling air box 22 is preferably 20-25.

M: Intermediate speed setting

The rotational speed ratio of the first intermediate wheel 24 and the second intermediate wheel 25 is 1:1 to 1:3, so that the stretched fiber has a forward effect, which can increase the crystallinity and strength of the polyurethane elastic fiber.

N: Finished coiling

Since the high-performance polyurethane elastomer produced by the present invention has a relatively high viscosity and melting point, it is very suitable for high-speed spinning, and its running and coiling speed can reach 1000-2500m/min, which can effectively increase the yield and reduce the cost. Polyurethane elastomer can only run at low speed (300-500m/min), and the production capacity is quite low; therefore, the present invention makes polyurethane elastic fiber with the produced polyurethane elastomer, which not only has low manufacturing cost, but also has obvious physical and chemical properties of the product Polyurethane elastic fiber produced beyond the traditional process.

Claims (10)

1. A method for producing high-performance polyurethane elastic fiber, characterized in that: the formula used in the manufacture of polyurethane elastomer wherein is to carry out pre-polymerization with polyester diol and diisocyanate, and then pre-polymerize The product and the chain extender are sent into the twin-screw extruder by a metering gear pump for reaction and extrusion to produce a polyurethane elastomer with high-performance physical and chemical properties, so as to make polyurethane elastic fiber by melt spinning. 2. A kind of manufacture method of high-performance polyurethane elastic fiber according to claim 1, is characterized in that: the polyester diol system adopts A, B two kinds of mixed use; The ingredients of category A are poly(tetramethylene adipate)glycol or poly(ε-caprolactone)glycol; Type B components are polyester diols made by reacting high-purity 36-carbon dimer acid with diols. 3. A method for producing high-performance polyurethane elastic fibers according to claim 2, wherein the molecular weights of the two types of polyester diols A and B are 500g/mole-3000g/mole. 4. A kind of manufacture method of high-performance polyurethane elastic fiber according to claim 2, is characterized in that: wherein the chemical structure of the 36 carbon dimer acid of B type polyester diol is: 5. A method for producing high-performance polyurethane elastic fibers according to claim 2, wherein the molar ratio of mixing the two types of polyester diols A and B is 95:5 to 5: 95. 6. A method for producing high-performance polyurethane elastic fibers according to claim 1, wherein the temperature of the pre-polymerization reaction is 60-80°C, the reaction time is 0.5-2 hours, and the reaction is carried out with nitrogen gas Fill into the pre-polymerization reaction tank. 7. A method for manufacturing high-performance polyurethane elastic fibers according to claim 1, wherein the formula ratio is: Polyester diol: chain extender: MDI = 1:1:2～1:10:11; the principle is that the number of moles of polyester diol + chain extender is equal to that of MDI (diisocyanate) ear count. 8. A method for producing high-performance polyurethane elastic fibers according to claim 1 or 2, wherein the chain extender is glycols, which can be divided into two parts, A and B; Part A is 1.4-butanediol, 1.6-hexanediol or 1.2-ethanediol, Part B is an aromatic binary group, and its chemical structure is:

Its m, n are integers 1, 2, 3, 4, 5, and m+n=2-10. 9 . A method for producing high-performance polyurethane elastic fibers according to claim 8 , wherein the molar ratio of A and B diols mixed is 95:5-5:95. 10. A method for producing high-performance polyurethane elastic fibers according to claim 1, wherein the drying temperature of the polyurethane elastomer is usually heated to 70-100°C with dew point -60°C absolute dry air .

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