CN204768734U - A production facility for preparing device and polyamide of polyamide - Google Patents

Abstract

The utility model provides a pre -polymerization device of preparation polyamide, heat including tubular reactor, three above being used for tubular reactor's heating jacket and one or more be used for to heating jacket provides the heat medium evaporimeter of heat medium. The utility model also provides a polyamide 5X's production facility. The utility model provides a pre -polymerization device heats, heat transfer efficiency is higher, and temperature control is more accurate, and the device operation is stable, and the convenience is maintained and is changed, effectively reduction in production cost. The utility model provides a polyamide 5X production facility is specific for polyamide 5X, can produce the polyamide 5X product of polytypic, can enlarge the production and application scope of polyamide 5X product.

Description

Plant for the preparation of polyamide and plant for the production of polyamide

technical field

The utility model relates to the field of polyamide, in particular to a device for preparing polyamide and polyamide production equipment comprising the device.

Background technique

In the prior art, polyamide polymerization methods can generally be classified into thermal polycondensation or interfacial polycondensation. For example: (BaconKe, A.W. Sisko, Differential thermal analysis of high polymers. III. Polyamides, Journal of Polymer Science Vol. 50 No. 153, No. 87-98, March 1961) records the heating polycondensation method, however, according to the report, the heating polycondensation method is compared with the interface In the polycondensation method, the polyamide produced has a low melting point and deteriorated heat resistance (J. Polym. Sci. 50, 87, 1961; Macromolecules, 30, 8540, 1998). However, the interfacial polycondensation process is very complicated and difficult to apply in industry. The above-mentioned processes are all short-range polymerization processes, no matter which process has certain defects, and the degree of polymerization of the prepared polyamide, especially polyamide 5X, is not high, and its industrial application is greatly restricted.

With the continuous development of the polymerization process, the continuous polymerization process came into being, which made up for the defects of short-range polymerization to a certain extent. At present, the main continuous polymerization process in the world mainly includes the following links: concentration→high pressure prepolymerization→flash evaporation→atmospheric pressure or vacuum polycondensation. As a world-renowned polyamide manufacturer, DuPont has improved the continuous polymerization process of polyamide 66. Its unique continuous polymerization process mainly includes the following links: high-pressure concentrated pre-polymerization→flash evaporation→normal compression polymerization.

In a continuous polymerization process, groups of equipment work together to apply heat to the reaction mixture and gradually remove water to drive the equilibrium of the reaction towards the polyamide until the polymer reaches the desired length range prior to extrusion Pellets, spun into fibers or processed into other shapes. The entire continuous polymerization process requires a large amount of heat to allow the condensation reaction to occur and remove water from the reaction mixture.

The continuous polymerization process of polyamide is very sensitive to temperature, and the existing polymerization reactors have limited ability to adjust the temperature, which leads to many problems. First, the heating rate is too high, leading to the formation of polyamide by-products as well as gels, which can clog the system, require reactor and other components to be shut down for cleaning, and contaminate the polyamide product. Second, when water vapor is formed in the reactor, it will increase the pressure in the reactor and form a mixture of water vapor and the reaction mixture, the increase in pressure causes the water vapor and the reaction mixture to travel along the reactor at a high speed, making it difficult to control the temperature of the reaction mixture, And complicates the separation of water vapor from the reaction mixture. The above-mentioned problems lead to the unsatisfactory polymerization effect of the polyamide reactor. In addition, most of the polymerization methods in the prior art are researches on polyamide 66. Polyamide 5X and polyamide 66 have different polymerization processes due to different polymerization raw materials.

For the prepolymerization step of the polyamide polymerization process, most of the existing devices or equipment are directed at the prepolymerization device of the polyamide 66 polymerization system, and are not suitable for polyamide 5X. For example, CN204051644U discloses a method for preparing polyamide The tubular reactor of amides, the temperature control effect of this tubular reactor is also not ideal. Therefore, designing a specific prepolymerization device or equipment for polyamide 5X products is one of the problems that need to be solved urgently.

Utility model content

In order to overcome the defects of the prepolymerization device in the existing polyamide production process, an object of the utility model is to provide a device for preparing polyamide.

The second purpose of this utility model is to provide a kind of production equipment of polyamide 5X.

The device for preparing polyamide provided by the utility model is a prepolymerization device, which includes: a tubular reactor, more than three heating jackets for heating the tubular reactor, and one or more heating jackets for heating the tubular reactor. The heating jacket provides heat medium to the heat medium evaporator.

In the device described in the present utility model, the tube body of the tubular reactor includes a plurality of connected straight tube parts and bent tube parts, and the exhaust ports are evenly distributed on the tube body.

In the device described in the present invention, the length of the pipe body is 50-180m, the inner diameter is 30-80cm, and the length/inner diameter ratio is 60-600.

In the device described in the utility model, the number of the exhaust ports is 3-30, and the distance between two adjacent exhaust ports is 6-20 cm.

In the device described in the utility model, the number of the heating jackets is 3-9.

In the device described in the utility model, each of the heating jackets is independently connected with a heat medium evaporator.

The polyamide 5X production equipment provided by the utility model includes a raw material concentration device, a prepolymerization device, a decompression device, a water separation device and a polycondensation device connected in sequence, wherein the prepolymerization device is described in any one of the above technical solutions installation.

In the production equipment described in the utility model, the polyamide 5X is polyamide 56.

The pre-polymerization device provided by the utility model adopts multiple heating jackets, the heating and heat transfer efficiency is higher, the temperature control is more precise, the material can be heated evenly and steadily in the tubular reactor, and the pre-polymerization process can be prevented to the greatest extent. The production of medium gel reduces the loss of raw material diamine; the prepolymerization device of the present invention uses multiple heat medium evaporators to provide heat medium to the heating jacket, which can realize multi-terminal control of temperature. The prepolymerization device of the present utility model Stable operation, convenient maintenance and replacement, can effectively reduce production costs.

The polyamide 5X production equipment provided by the utility model adopts the prepolymerization device provided by the utility model, which ensures the prepolymerization production link, and is especially suitable for the precondensation process steps of polyamide 5X, and can produce polyamide 5X products of various types , can expand the production and application range of polyamide 5X products, and has very industrial value.

Description of drawings

Fig. 1 is the structural representation of the prepolymerization device described in the utility model;

Fig. 2 is the structural representation of the tubular reactor in the prepolymerization device described in the utility model;

Fig. 3 is the structural representation of polyamide 5X production equipment described in the utility model;

Wherein, reference signs are explained as follows: 0, salt forming device; 1, raw material concentration device; 2, prepolymerization device; 3, decompression device; 4, water separation device; 5, polycondensation device; 21, tubular reactor; 22. Heating jacket; 23. Heat medium evaporator; 211. Straight pipe part; 212. Bend pipe part; 213. Exhaust port; 214. Material inlet; 215. Material outlet.

Detailed ways

One aspect of the present utility model provides a kind of prepolymerization device for preparing polyamide, as shown in Figure 1, the prepolymerization device of the present utility model comprises tubular reactor 21, three or more are used for heating tubular reaction The heating jacket 22 of the device 21 and one or more heat medium evaporators 23 for supplying heat medium to the heating jacket 22.

When the above-mentioned prepolymerization device is in use, the heat medium evaporator 23 provides heat medium to the heating jacket 22, so that the heating jacket 22 heats the tubular reactor 21, and the monomer material undergoes polycondensation reaction in the tubular reactor 21 to form a prepolymerization reaction. Polymer.

As shown in Figure 2, in one embodiment of the prepolymerization device according to the present utility model, the tubular reactor 21 includes a material inlet 214, a material outlet 215 and a pipe body, and the pipe body then includes several connected straight pipe parts 211 and The bent pipe portion 212 has exhaust ports 213 evenly distributed on the pipe body. The monomer material enters the pipe body from the material inlet 214 and is transported therein. The heating jacket 22 heats the pipe body. The monomer material is polycondensed in the pipe body to form a prepolymer, and is discharged from the material outlet 215 into the downstream processing unit. The polycondensation process The gas generated in the gas is exhausted through the exhaust port 213.

In one embodiment of the prepolymerization device according to the present utility model, the prepolymerization device of the present utility model is applicable to common polyamide 6X series, such as nylon 66, etc., and also applicable to polyamide 5X series, such as polyamide 56 wait. In a preferred embodiment, the prepolymerization device of the present invention is especially suitable for the field of polyamide 5X production.

In one embodiment of the prepolymerization device according to the present invention, the tubular reactor can be a common type in the field of polymerization, preferably a horizontal or vertical reactor, more preferably a horizontal reactor.

In one embodiment of the prepolymerization device according to the present invention, the length of the pipe body is 50-180 m, the inner diameter is 30-80 cm, and the length/inner diameter ratio is 60-600.

In one embodiment of the prepolymerization device according to the present invention, the inner diameter of the pipe body may be uniform or variable. For example, the inner diameter can gradually expand from the material inlet of the tubular reactor to the material outlet of the tubular reactor, such as linearly or non-linearly. The inner diameter may also expand sufficiently so that, when using the reactor, a substantially constant pressure is maintained from the inlet to the outlet of the reactor, or the pressure decreases from the inlet to the outlet. In a preferred embodiment, the inner diameter of the tubular reactor body is constant.

In one embodiment of the prepolymerization device according to the present invention, the number of exhaust ports 213 is 3-30, and the distance between two adjacent exhaust ports is 6-20 cm.

In one embodiment of the prepolymerization device according to the present invention, the number of heating jackets may preferably be 3-9. In the existing prepolymerization device, the same heating jacket is mostly used for the whole tubular reactor. When the temperature of the heat medium in the heating jacket fluctuates or gets out of control, it will directly affect the temperature change of the tubular reactor. Therefore, the temperature of the tubular reactor It is difficult to realize multi-terminal control. The prepolymerization device of the utility model is equipped with multiple heating jackets, which can effectively overcome this defect and realize multi-terminal control of the heating temperature.

In one embodiment of the prepolymerization device according to the utility model, the setting form of the heating jacket is not limited, and can be: for example, the tubular reactor is divided into several sections, and each section is provided with a heating jacket separately; For example, a heating jacket (as shown in Figure 1) is installed separately on each straight pipe section of the tubular reactor. Compared with the curved pipe section, it is easier to install a heating jacket on the straight pipe section, which can simplify the operation difficulty , At the same time realize the role of multi-terminal temperature control.

In one embodiment of the prepolymerization device according to the present utility model, the heat medium used in the heating jacket can be an organic heat medium, and a gas-phase heat medium heating method in which the organic heat medium is superheated and liquid-phase transported and evaporated on the spot is adopted, and the gas-phase heat medium is heated Tubular reactor, the used heat medium condensate is recovered and sent back to the heat medium evaporator for recycling and heating.

In one embodiment of the pre-polymerization device according to the utility model, the quantity of the heat medium evaporator can be one or multiple, preferably multiple, and the heat medium evaporator can provide single or multiple heating pipe jackets Heat medium (as shown in Figure 1, where only one heat medium evaporator is marked as an example), in a preferred embodiment, each heating jacket is connected with a heat medium evaporator separately, so as to better realize the temperature control to improve the operational stability of the tubular reactor.

The second aspect of the present utility model provides a kind of production equipment of polyamide 5X, as shown in Figure 3, comprises the raw material concentrating device 1, prepolymerization device 2, decompression device 3, water separation device 4 and polycondensation device connected successively Device 5, wherein the pre-polymerization device 2 is the pre-polymerization device described in any one of the above technical solutions.

In one embodiment of the production equipment according to the present invention, the upstream of the raw material concentration device 1 may also be connected with a salt forming device 0 for forming the raw material polyamide salt, as shown in FIG. 3 .

The raw material concentration device, decompression device, moisture separation device and polycondensation device involved in the utility model can adopt any type in the existing polyamide production field. device used together.

The raw material concentration device that can be used in the production equipment of the present utility model can be a concentration kettle, in which the raw material is heated and evaporated to achieve the required concentration. The heating source can be a conventional external steam heat source, or a tubular reactor in the prepolymerization device. The exhausted superheated process steam heat source, the steam temperature is generally 220-280°C, and the concentration kettle generally adopts the shell-and-tube type concentration kettle. The raw material concentration device may further include a preheating device, which can preheat the raw material solution before concentration, and then carry out evaporation and concentration. The raw material concentration device can further include a condensation tower. The process steam generated by the concentration tank can be condensed to recycle heat energy, and the raw materials such as diamine entrained in the steam can also be condensed and returned to the concentration tank to reduce the concentration of raw materials. loss.

The decompression device that can be used in the production equipment of the utility model can be a horizontal flash evaporator, including a kettle body, and a serpentine material coil is arranged in the kettle body, and the inner diameter of the material coil increases sequentially from the inlet. The pre-polymerized material is pressurized at the inlet of the material coil (generally 20-25kg/cm ² ), and the material flows in the coil. Due to the gradual increase of the inner diameter and the resistance effect of the friction between the material and the coil wall , the pressure drops rapidly and drops to close to normal pressure at the outlet. The moisture in the material expands and vaporizes rapidly at high temperature due to the pressure drop. The material flows at a high speed in the form of a ring-shaped film on the inner wall of the coil, and the water vapor flows through the center of the coil. The polymer in the material at the outlet of the coil can reach 99%, and at the same time, the pressure energy is converted into kinetic energy, so that the mixture of material and water enters the subsequent water separation device at a high speed.

The water separation device that can be used in the production equipment of the present utility model can be any type in the art, including normal pressure or pressurized separation device. For example, the prepolymer entrained with a large amount of water vapor can directly enter the normal pressure separation device from the decompression device, and the water vapor is separated from the prepolymer in the device. The temperature of the separation step is preferably 250 ~ 320 ° C, more preferably 250～300℃. The kettle body of the separation device 4 can be heated by a gas-phase heat medium in which the organic heat medium is superheated and liquid-phase transported and evaporated on the spot. The superheated liquid phase heat medium heated from the heat medium furnace is transported to the flash evaporator at the heating site under a certain pressure for decompression flash evaporation, and the gas phase heat medium heated by the flash evaporates to heat the separator, and the used heat medium condensate passes through After the liquid trap is received by the medium condensate recovery tank, it is sent back to the heat medium heating furnace by the heat medium circulation pump for circulation heating. The extrusion cylinder of the separation device is heated by liquid-phase heat medium.

The polycondensation device that can be used in the production equipment of the utility model can be any type in the art, including normal pressure or pressurized separation device. For example, the liquid material (mainly prepolymer) treated by the water separation device enters the polycondensation device under the action of the supply pump of the polycondensation device, and the prepolymer undergoes further polymerization in the polycondensation tank of the polycondensation device to form a final poly things. The polymer produced in the polycondensation device can be transported to the casting head through the melt pump for extrusion granulation, or sent to the screw extruder for modified granulation, or sent to direct spinning. The kettle body of the polycondensation device can be heated by a gas-phase heat medium in which the organic heat medium is superheated and liquid-phase transported and evaporated on the spot. The superheated liquid-phase heat medium heated from the heat medium furnace is transported to the flash evaporator at the heating site under a certain pressure for flash evaporation, and the flash-evaporated gas-phase heat medium heats the kettle body of the polycondensation device, and the used heat medium condenses After being received by the medium condensate recovery tank through the liquid repellent, it is sent back to the heat medium heating furnace by the heat medium circulation pump for circulation heating. The extrusion cylinder of the polycondensation device can be heated by liquid phase heat medium.

The production method of the production equipment of the utility model is as follows: the polyamide 5X is prepared by using the polyamide salt solution as a starting material, and successively undergoes a raw material concentration step, a prepolymerization step, a decompression step, a water separation step and a polycondensation step.

In one embodiment, the mass percent concentration of the polyamide salt solution as the starting material may be more than 50%, preferably 50-65%.

In one embodiment, in the raw material concentration step, a common shell-and-tube heat exchange device can be used for evaporation and concentration, wherein the tube-side pressure can be 0.005-0.35 MPa, preferably 0.05-0.35 MPa, and the tube-side temperature can be 60 ～200°C, preferably 80～160°C; the shell side pressure can be 0～2.0MPa, the shell side temperature can be below 250°C, preferably below 212°C; the mass percentage concentration of the polyamide salt solution obtained after concentration can be 50-80%, preferably 70-80%.

In one embodiment, in the pre-polymerization step, the pre-polymerization temperature can be 200-300°C, preferably 220-280°C, more preferably 230-260°C; the pre-polymerization pressure can be below 3.0 MPa, preferably 2.0 MPa MPa or less, more preferably 1.0 to 1.8 Mpa.

In one embodiment, the mass percentage content of the polymer obtained after the prepolymerization step may be 80-100%, preferably 85-95%.

In one embodiment, the decompression step can be carried out using a flash evaporator, the temperature and pressure in the flash evaporator are any conditions suitable for the flash separation of polyamide 5X and moisture, and the decompression temperature can be a temperature above the melting point of polyamide 5X , preferably 200 to 300°C, more preferably 230 to 260°C.

In one embodiment, the temperature in the water separation step may be 250-320°C, preferably 250-300°C.

In one embodiment, the polycondensation step is carried out under normal pressure or vacuum conditions, and an inert gas (such as nitrogen, etc.) is used to protect the polycondensation under normal pressure. 250mmHgA, the temperature of the polycondensation step can be 250-320°C, preferably 250-300°C.

In one embodiment of the production plant according to the invention, polyamide 5X is preferably polyamide 56.

The polyamide 5X described in the present invention refers to a series of polyamides formed by polycondensation reaction of 1,5-pentamethylenediamine and organic dibasic acid.

The polyamide production equipment described in the utility model is suitable for continuous polymerization process and intermittent polymerization process of polyamide, especially suitable for continuous polymerization process of polyamide.

The formic acid relative viscosity of the polyamide 5X prepared by the production equipment of the utility model is preferably 45-100, and the amino-terminal content is preferably 10-100 mol/ton, more preferably 20-60 mol/ton. And prone to side effects.

The polyamide 5X molecular weight distribution that the utility model production equipment makes is narrow, represents Mw/Mn with the polydispersity coefficient d of molecular weight distribution commonly used; Mw represents the weight-average relative molecular mass with weight as statistical weight:

${\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

Mn represents the number-average relative molecular mass with the number as the statistical weight:

${\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

The d value of the polyamide 5X prepared by the production equipment of the utility model is less than 2.5.

The polyamide 5X prepared by the production equipment provided by the utility model can be made into polyamide resins for various purposes together with other polymers and/or additives. Generally speaking, the amount of polyamide 5X can account for more than 80% of the mass of polyamide resin.

Additives can be any of antioxidants, heat-resistant stabilizers, weather-resistant agents, pigments, gloss enhancers, dyes, crystal nucleating agents, matting agents, plasticizers, antistatic agents, flame retardants, metals and metal salts one or a combination of several.

Wherein, the heat-resistant stabilizer can be any type existing in the art, including but not limited to hindered phenol-based compounds, hydroquinone-based compounds, thiazole-based compounds, phosphorus-based compounds (such as phenylphosphonic acid), based on Imidazole compounds (such as 2-mercaptobenzimidazole) and its substitution products, copper halides and iodine compounds, etc.

The weather resistance agent can be any type existing in the art, including but not limited to resorcinol, salicylate, benzotriazole, benzophenone, and hindered amine.

The pigment can be any type existing in the art, including but not limited to cadmium sulfide, phthalocyanine, and carbon black.

The gloss enhancer can be any type existing in the art, including but not limited to titanium oxide, calcium carbonate, and the like.

The dye can be any type existing in the art, including but not limited to nigre black, nigrosine and the like.

The crystal nucleating agent can be any type existing in the art, including but not limited to talc, silica, kaolin and clay.

The plasticizer can be any type existing in the art, including but not limited to octyl p-oxybenzoate and N-butylbenzenesulfonamide.

Antistatic agent can be any type existing in the art, including but not limited to alkyl sulfate type anionic antioxidant, quaternary ammonium salt type cationic antistatic agent, nonionic antistatic agent (such as polyoxyethylene sorbose Alcohol monostearate) and betaine-based amphoteric antistatic agents, etc.

Flame retardants can be of any type available in the art, including but not limited to melamine cyanurate, hydroxides (such as magnesium hydroxide or aluminum hydroxide), ammonium polyphosphate, brominated polystyrene, brominated polystyrene Phenyl ethers, brominated polycarbonates, brominated epoxies, combinations of any bromine-based flame retardant with antimony trioxide, etc.

Other polymers include but are not limited to the following polymers: (1) Other polymers may contain structural units derived from the following components: aliphatic carboxylic acids (such as oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid , suberic acid, azelaic acid, etc.), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid, etc.) or aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl Dicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenylethane dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, etc.).

(2) Other polymers may contain structural units derived from the following components: aliphatic diamines other than 1,5-pentanediamine (such as ethylenediamine, 1,3-diaminopropane, 1,4- Diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-Diaminoundecane, 1,12-Diaminododecane, 1,13-Diaminotridecane, 1,14-Diaminotetradecane, 1,15-Diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane or 2-methyl-1,5-pentanediamine), cycloaliphatic diamines (such as cyclohexanediamine or bis-(4-aminohexyl)methane), or aromatic diamines (such as xylylenediamine).

(3) Other polymers may contain structural units derived from the following components: aromatic, aliphatic or alicyclic diol compounds (such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 1 ,4-cyclohexanedimethanol, neopentyl glycol, hydroquinone, resorcinol, dihydroxybiphenyl, naphthalene diol, anthracene diol, phenanthrene diol, 2,2-bis(4-hydroxyphenyl) propane, 4,4'-dihydroxydiphenyl ether or bisphenol S).

(4) Other polymers may contain a structural unit derived from an aromatic compound having a hydroxyl group and a carboxylic acid, an aliphatic compound, or an alicyclic hydroxycarboxylic acid compound. Among them, alicyclic hydroxycarboxylic acids include but are not limited to lactic acid, 3-hydroxypropionate, 3-hydroxybutyrate, 3-hydroxybutyrate-valerate, hydroxybenzoic acid, hydroxynaphthalenecarboxylic acid, hydroxyanthracene Carboxylic acid, hydroxyphenanthrene carboxylic acid, (hydroxyphenyl) vinyl carboxylic acid.

(5) Other polymers may contain structural units derived from amino acids (such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, or p-aminomethylbenzoic acid) or Lactams (such as ε-caprolactam or ε-laurolactam).

(6) Other polymers can be comonomers that can be copolymerized with 1,5-pentanediamine and aliphatic long carbon chain dibasic acids, including but not limited to amino acids, lactams, aromatic dicarboxylic acids, Aliphatic dicarboxylic acid, cycloaliphatic dicarboxylic acid, aromatic diol, aliphatic diol, cycloaliphatic diol, aromatic diamine, aliphatic diamine, cycloaliphatic diamine, aromatic hydroxycarboxylic acid , aliphatic hydroxycarboxylic acids, alicyclic hydroxycarboxylic acids, and respective derivatives of the aforementioned comonomers. Wherein, the respective derivatives of the above-mentioned comonomers include the products of the reaction of any two of the above-mentioned comonomers, for example, the product of the reaction of an amino group of a certain diamine with a carboxyl group of a certain dicarboxylic acid to form a salt.

The utility model is described in detail below through the embodiments, so that the features and advantages of the utility model are clearer. However, it should be pointed out that the examples are used to understand the concept of the present utility model, and the scope of the present utility model is not limited only to the examples listed herein.

If not otherwise specified, the concentrations described in the present invention are all mass percent concentrations.

The polyamide starting material used in the examples was an aqueous solution of a polyamide salt formed from bio-based 1,5-pentanediamine and an aliphatic dibasic acid.

[1,5-pentanediamine]

1,5-Pentanediamine (referred to as pentamethylenediamine, also known as 1.,5-diaminopentane), also known as cadaverine, is a kind of polyamine, which is a nitrogen-containing compound with biological activity widely existing in organisms. The base is produced by the decarboxylation reaction of lysine under the action of decarboxylase when the protein is spoiled. Industrially, pentamethylenediamine can also be obtained by chemical methods, for example, after boiling the absolute ethanol solution of glutaronitrile, sodium metal is added at a faster speed, after the reaction is completed, water is added, and the ethanol is distilled out, and the remaining reactants are heated It can be obtained by steam distillation, acidification and neutralization, and distillation. In recent years, it has been found that pentamethylenediamine can be obtained by a biological method in which lysine decarboxylase (L-lysinedecarboxylase, EC4.1.1.18) in Hafnia.Alvei acts on lysine. The 1,5-pentanediamine in the embodiment of the present invention can be prepared by biological method or chemical method, and can contain organic carbon from renewable sources that meets the standard of ASTM D6866.

[Aliphatic dibasic acid]

Aliphatic dibasic acids, including adipic acid and aliphatic long carbon chain dibasic acids. Aliphatic long carbon chain dibasic acids can also be prepared by biological or chemical methods, and can also contain bio-based organic carbon that meets the standard of ASTM D6866.

The aliphatic long carbon chain dibasic acid can be sebacic acid, undecane dibasic acid, dodecane dibasic acid, thirteen carbon dibasic acid, tetradecane dibasic acid, pentadecane dibasic acid, hexadecanoic acid Any one or a combination of carbon dibasic acid, heptadecandioic acid, octadecanedioic acid and Δ9-1,18-octadecene dibasic acid, preferably sebacic acid or decadioic acid Two carbon dibasic acids.

The continuous production process of polyamide is as follows:

(1) Preparation of polyamide salt solution

Under the protection of nitrogen, the high-concentration 1,5-pentanediamine is diluted with degassed deionized water to a certain concentration solution (30%-50%). The aliphatic dibasic acid and the diluted 1,5-pentanediamine are continuously added to the reactor at the same time, and the cooling water removes the heat of reaction during the neutralization reaction in time. During the neutralization process, the pH value of the solution is constantly detected, so that the mol ratio of the diamine/diacid in the reactor is slightly lower than 1. After stabilization, the resulting salt solution is transferred to the reactor in series behind (can be connected in series) multiple units, but generally not more than 3 units), use diamine aqueous solution to further neutralize step by step and adjust the molar ratio of diamine/diacid and the mass concentration of salt, and control the flow of diamine aqueous solution with the data of pH detection. Finally, a saline solution with a mass percent concentration of 50-65% is prepared and stored in a salt storage tank for use.

(2) Concentration device and its reaction

Use 5X polyamide salt solution with a mass percentage concentration of 50-65% as the starting material, filter through a filter, and send it to the metering tank in batches. A certain amount of common additives of different specifications can be added to the metering tank (generally not more than 5% of the polyamide salt quality) to make a polyamide salt mixed solution, which is sent into the second intermediate tank under the metering tank after stirring and mixing evenly. The polyamide salt mixture in the second intermediate tank is continuously supplied to the concentration device by the salt supply pump through the salt filter and the salt preheater. In the concentration device, the concentration of the polyamide salt solution is concentrated from 50-65% to 70-80%.

(3) Prepolymerization device and its reaction

The concentrate in the concentration unit is pumped to the prepolymerization unit with the reactor supply pump.

The prepolymerization reaction occurs gradually with the continuous flow of polyamide salt solution in the tubular reactor under controllable high temperature and high pressure. During this period, the pressure of the reactor is automatically controlled, and the tubular reactor is divided into more than three sections for independent heating. 90% (concentration suitable for polymerization reaction), the last section is mainly for pre-polymerization, and the polymer content in the exported material can reach 85-95%.

(4) Decompression device and its reaction

The prepolymer produced by the tubular reactor is continuously sent to the pressure reducer (flasher) with a pressure reducer pump. The material quickly passes through the pressure reducer, and the pressure is continuously reduced to close to the atmospheric pressure, so the dissolved water in the prepolymer is quickly vaporized from the prepolymer to form a mixture of material and water.

The pipeline between the pressure reducer pump and the pressure reducer can also be equipped with an additive inlet, and the type and amount of additives can be determined according to the use of the PA5X resin, such as the suspension of the matting agent _TiO2 , etc., through the additive inlet , It can be continuously and quantitatively injected into the prepolymer at this stage, and finally forms a mixture of materials, moisture and additives after decompression by a decompression device.

(5) Separation device and its reaction

The material continuously enters the water separator after passing through the pressure reducer. In the separator, the moisture vaporized from the pressure reducer is removed to further increase the degree of polymerization of the prepolymer.

(6) Final polymerization device and its reaction

Use a total pump to send the materials passing through the separator into the final polymerization device (final polymerization tank). In the final polymerization device, the residual water in the polymer and the water produced by further polymerization are removed under negative pressure conditions to obtain suitable granulation or Modified or direct spun high quality polymers. In order to prevent the oxidation of the materials in the separator and the final polymerization tank, it is preferable to adopt nitrogen sealing.

Following is the embodiment that prepares PA56:

Example 1

Configuration pH is the polyamide 56 salt solution of 65% concentration of 7.95, carries out polymerization by the processing condition of table 1 by the production equipment described in the utility model, and final polymerization tank pressure 210mmHgA, obtains the slice that relative viscosity is 68.9, and its terminal amino content is 40.4.

Example 2

Configuration pH is the polyamide 56 salt solution of 65% concentration of 8.05, carries out polymerization by the processing condition of embodiment 1 by the production equipment described in the utility model, but the pressure of final polymerization kettle is adjusted to 180mmHgA strongly, and output is higher than embodiment 1 was increased by 20%, and the chips with a relative viscosity of 69.7 and an amino-terminal content of 40.1 were obtained.

Example 3

Except that the pressure in the final polymerization tank was changed to 216mmHgA, other conditions were the same as in Example 2, and the output was also the same. The obtained slices had a relative viscosity of 56.1 and a terminal amino group content of 42.6.

Table 1

The above embodiments are only explanations of the technical solutions, and do not constitute limitations on the technology of the present utility model. According to professional knowledge, those skilled in the art can realize polyamide resins with different end group contents and relative viscosities by adjusting the ratio of raw materials and process conditions in the preparation process.

Unless otherwise specified, the terms used in the present invention are the meanings commonly understood by those skilled in the art.

The embodiments described in the utility model are only for exemplary purposes, and are not intended to limit the protection scope of the utility model. Those skilled in the art can make various other replacements, changes and improvements within the scope of the utility model. Therefore, The present invention is not limited to the above-described embodiments, but only by the claims.

Claims (8)

1. A device for preparing polyamide, characterized in that, the device is a prepolymerization device, comprising a tubular reactor, more than three heating jackets for heating the tubular reactor and one or A plurality of heat medium evaporators for supplying heat medium to the heating jacket. 2 . The device according to claim 1 , wherein the tube body of the tubular reactor includes several connected straight tube sections and bent tube sections, and exhaust ports are uniformly distributed on the tube body. 3 . 3 . The device according to claim 2 , wherein the length of the pipe body is 50-180 m, the inner diameter is 30-80 cm, and the length/inner diameter ratio is 60-600. 4 . 4 . The device according to claim 2 , wherein the number of the exhaust ports is 3-30, and the distance between two adjacent exhaust ports is 6-20 cm. 5. The device according to any one of claims 1-4, characterized in that, the number of the heating jackets is 3-9. 6. The device according to claim 5, characterized in that, each of the heating jackets is individually connected with a heat medium evaporator. 7. A kind of production equipment of polyamide 5X, it is characterized in that, comprises the raw material concentrating device, prepolymerization device, decompression device, water separation device and polycondensation device connected successively, wherein, described prepolymerization device is claim 1- 6. The device of any one of the claims. 8. The production equipment according to claim 7, characterized in that the polyamide 5X is polyamide 56.