Nylon 6 micromolecule removal device

Abstract

The utility model relates to the technical field of nylon materials, and discloses a nylon 6 micromolecule removal device which comprises a removal container and a devolatilization assembly arranged in the removal container, the devolatilization assembly comprises a rotating shaft and a plurality of devolatilization pieces arranged on the rotating shaft in a sleeving mode, and a plurality of air holes communicated with the rotating shaft are formed in the devolatilization pieces; according to the device, the rotating shaft drives the removal part to rotate, the bottom of the removal part can be immersed in the melt, the part, immersed in the melt, of the removal part can be separated from the melt when the removal part rotates, the melt is made to adhere to the surface of the removal part, a layer of melt film is formed, and the devolatilization specific surface area of the melt is remarkably increased; the problem of solution accumulation in the removal process is avoided; according to the device, the air holes communicated with the rotating shaft are formed in the devolatilization piece, wet nitrogen blows a melt film tightly attached to the surface of the devolatilization piece into bubbles through the air holes, the devolatilization area is further increased, meanwhile, the wet nitrogen can conduct water extraction on small molecules of the melt film, the removal efficiency of small molecule impurities is remarkably improved, and the energy consumption and the water demand are remarkably reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of nylon materials, in particular to a nylon 6 small molecule removal device. Background Art

[0002] Nylon 6 fiber (PA6) is a synthetic fiber with excellent physical properties and textile processing properties. It is made by hydrolysis and polymerization of caprolactam. Since the conversion rate of caprolactam hydrolysis and polymerization is usually 90%, the polymer will also contain 10% of small molecular monomers, cyclic dimers and other small molecular impurities. These small molecular impurities will cause the spinning performance of nylon 6 fiber to be significantly reduced. Therefore, the small molecular monomers need to be removed.

[0003] At present, the method for removing small molecules of nylon 6 in the prior art is mainly a hydrothermal extraction method, such as a nylon 6 melt direct spinning method and device disclosed in Publication No. CN113463214B, in which hot water is used as an extractant to pre-remove small molecular impurities in the polymer, and then a fine devolatilization device is used to post-remove small molecular impurities in the polymer, so that the content of hot water extractables is ≤1.5 wt%, and the content of cyclic dimers is ≤0.3 wt%. However, this method consumes a large amount of water and energy, and has a high production cost. In addition, Publication No. CN215841705U also discloses a polymer melt pre-spinning devolatilization device, which forms a thin flow of the melt through the devolatilization holes on the devolatilization distribution plate, which can significantly increase the specific surface area of ​​the melt thin flow and enable gaseous monomers and oligomers to be separated from the melt surface. However, the device has the problem that the melt accumulates on the devolatilization distribution plate, resulting in a significant increase in the local viscosity of the melt and difficulty in uneven melt molding. Summary of the invention

[0004] In order to overcome the problems of large water demand, high energy consumption and increased local viscosity of melt accumulation in nylon 6 small molecule removal devices in the prior art, the utility model provides a nylon 6 small molecule removal device, which is composed of a removal container and a devolatilization component arranged in the removal container, the devolatilization component includes a rotating shaft and a devolatilization piece sleeved on the rotating shaft, and the devolatilization piece is provided with a pore connected to the rotating shaft. The device drives the devolatilization piece to rotate through the rotating shaft, and the rotating devolatilization piece drives the melt so that the melt can adhere to the surface of the devolatilization piece. The melt flows under the action of gravity and flows on the surface of the devolatilization piece. The film layer structure of the melt film formed has a larger specific surface area, which can significantly increase the removal area of ​​small molecular impurities, and the problem of excessive local viscosity and uneven molding of the melt accumulation will not occur during the removal process. At the same time, the wet nitrogen gas is led to the pores from the rotating shaft, and the melt film is blown into melt bubbles through the pores, further increasing the specific surface area of ​​the melt. At the same time, hydrothermal steam extracts the melt combined with the surface of the devolatilization part. When the bubbles are broken, the wet nitrogen after the small molecules are extracted will leave the melt, significantly improving the removal efficiency of small molecular impurities in the pre-removal process and significantly reducing energy consumption and water demand.

[0005] The specific technical scheme of the present invention is:

[0006] A nylon 6 small molecule removal device comprises a removal container and a devolatilization component arranged in the removal container, wherein the devolatilization component comprises a rotating shaft and a plurality of devolatilization parts sleeved on the rotating shaft, wherein the devolatilization parts are provided with a plurality of pores connected to the rotating shaft.

[0007] The utility model provides a nylon 6 small molecule removal device, which is composed of one or more removal units. The removal unit comprises a removal container and a removal component arranged in the removal container. The removal component comprises a rotating shaft and a plurality of removal parts sleeved on the rotating shaft. The removal parts are provided with a plurality of pores connected with the rotating shaft. The device can significantly improve the removal efficiency of small molecule impurities in the nylon 6 polymer during the pre-removal treatment, and can significantly reduce energy consumption and water demand, and can make the content of hot water extractables of the nylon 6 polymer ≤3 wt%, and in the process of stripping, there will be no problem of melt accumulation, local viscosity increase and melt non-forming; the device first drives the stripping piece to rotate through the rotating shaft, the bottom of the stripping piece will be immersed in the melt, and when the stripping piece rotates, the part immersed in the melt will separate from the melt and make the melt adhere to the surface of the stripping piece, and the part not immersed in the melt will continue to be immersed in the melt as the stripping piece rotates, and separate from the melt again as the rotation makes the melt adhere to the surface of the stripping piece, the melt adhered to the surface of the stripping piece flows under the action of gravity, and the excess melt will separate from the surface of the stripping piece and finally form a layer of melt film on the surface of the stripping piece, forming a melt film The devolatilization specific surface area is significantly increased while the problem of melt accumulation during the stripping process does not occur; in addition, since one side of the melt film is in close contact with the surface of the stripping piece, only the side of the melt film that is not in close contact with the surface of the stripping piece can devolatilize small molecules. Therefore, in order to further increase the devolatilization area, the utility model is provided with an air hole connected to the rotating shaft on the devolatilization piece, and the wet nitrogen entrained with hydrothermal steam is passed into the air hole from the rotating shaft, and the wet nitrogen then blows the melt film in close contact with the surface of the devolatilization piece into bubbles through the air hole. When the melt film forms bubbles, the devolatilization area is further increased. At the same time, the hydrothermal steam in the wet nitrogen can extract water from the melt film, thereby significantly improving the removal efficiency of small molecule impurities.

[0008] Preferably, the pore size is 0.1-10 mm, and the spacing between the pore and its adjacent pore is 0.2-20 mm; by setting the pore size and spacing, the size of the bubbles formed can be controlled to ensure that the specific surface area of ​​the bubbles formed is optimal, and the hydrothermal extraction process is optimal, ensuring that the removal efficiency of small molecule impurities is optimal.

[0009] Preferably, the cross section of the devolatilizer is a circular ring, a pore channel is provided inside the devolatilizer, the pore channel is connected to the rotating shaft, and a plurality of devolatilization holes are provided on the outer edge of the devolatilizer; the devolatilizer is set as a circular ring, which can ensure that the excess melt on the devolatilizer can be better separated from the devolatilizer when flowing, and ensure that the excess melt will not stay on the devolatilizer for a long time. The outer edge of the devolatilizer still has a plurality of devolatilization holes to further increase the devolatilization specific surface area of ​​the melt film, so that the side of the melt film in contact with the surface of the devolatilizer can also be devolatilized with small molecules.

[0010] Preferably, the diameter of the devolatilization hole is 4-5 mm, and the interval between the devolatilization hole and its adjacent devolatilization hole is 9-10 mm.

[0011] Preferably, the interval between the devolatilizer and its adjacent devolatilizer is 5-10 cm.

[0012] Preferably, a support body is further provided on the devolatilization component, and the support body communicates with the air hole and the rotating shaft.

[0013] Preferably, a channel is provided in the support body, and the channel connects the air hole and the rotating shaft.

[0014] Preferably, a shaft hole is provided in the shaft, and the shaft hole is connected to a wet nitrogen device.

[0015] Preferably, the stripping container comprises a shell, a driving member arranged on the shell, an exhaust hole arranged on the top of the shell, a melt inlet arranged on the bottom of the shell, and a melt outlet arranged on the bottom of the shell, and the driving member is detachably connected to the rotating shaft. The driving member on the stripping container is used to drive the rotating shaft to rotate, and the exhaust hole is used to discharge the small molecular impurities after the devolatilization.

[0016] Preferably, the removal container is a horizontal reaction container, and the devolatilizer is vertically arranged in the horizontal reaction container.

[0017] Compared with the prior art, this application has the following technical effects:

[0018] 1. The device drives the stripping piece to rotate through a rotating shaft, and the bottom of the stripping piece will be immersed in the melt. When the stripping piece rotates, the part immersed in the melt will separate from the melt and make the melt adhere to the surface of the stripping piece and form a layer of melt film, which can significantly increase the devolatilization specific surface area of ​​the melt, and at the same time, there will be no problem of melt accumulation during the stripping process;

[0019] 2. The device is provided with an air hole connected to the rotating shaft on the devolatilization component, and wet nitrogen carrying hydrothermal steam is passed into the air hole from the rotating shaft. The wet nitrogen then blows the melt film close to the surface of the devolatilization component into bubbles through the air hole. When the melt film forms bubbles, the devolatilization area is further increased. At the same time, the hydrothermal steam in the wet nitrogen can extract water from the melt film, significantly improving the removal efficiency of small molecular impurities. The device uses wet nitrogen, and the energy consumption and water demand are significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a partial cross-sectional view of the nylon 6 small molecule removal device of the utility model.

[0021] Figure 2 It is a cross-sectional view of the devolatilizer and the rotating shaft of the utility model.

[0022] Figure 3It is a schematic diagram of the composition of Example 4 of the present utility model.

[0023] Figure 4 It is a schematic diagram of the composition of Example 5 of the present utility model.

[0024] In the figure, a stripping container 1, a shell 101, a driving member 102, an exhaust hole 103, a melt inlet 104, a melt outlet 105, a devolatilization component 2, a rotating shaft 201, a rotating shaft channel 211, a devolatilization member 202, an air hole 221, an air hole channel 222, a devolatilization hole 223, a support body 203, a channel 231, a hydrothermal stripping group 3 and a post-stripping group 4. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments.

[0026] Embodiment 1:

[0027] like Figure 1 As shown, a nylon 6 small molecule removal device comprises a removal container 1 and a devolatilization assembly 2 arranged in the removal container, the removal container is a horizontal reaction container, the removal container comprises a shell 101, a driving member 102 arranged on the shell, an exhaust hole 103 arranged on the top of the shell, a melt inlet 104 arranged on the bottom of the shell, and a melt outlet 105 arranged on the bottom of the shell, and the driving member is a driving motor;

[0028] like Figure 2 As shown, the devolatilization assembly includes a rotating shaft 201 and four devolatilization parts 202 sleeved on the rotating shaft, the interval between the devolatilization parts is 10 cm, the rotating shaft is a hollow rotating shaft with a rotating shaft channel inside, one end of the rotating shaft is detachably connected to a driving motor, the driving motor drives the rotating shaft to rotate, and the other end of the rotating shaft is connected to a wet nitrogen device, and the wet nitrogen device can pass wet nitrogen into the rotating shaft airway;

[0029] Four devolatilizers are arranged at intervals on the rotating shaft. The devolatilizer is in a circular ring shape. Three support bodies are arranged on the inner ring of the devolatilizer. The support bodies are sleeved on the rotating shaft. A channel is arranged in the support body. The channel is connected with the rotating shaft air channel. After the wet nitrogen enters the rotating shaft air channel, it can continue to pass into the channel. The devolatilizer is provided with a plurality of pores 221 and a plurality of devolatilizer holes 223 arranged along the annular ring surface. The inner diameter of the devolatilizer hole is 5 mm, and the interval between adjacent devolatilizer holes is 10 mm. A pore channel 222 is arranged inside the devolatilizer. The pore channel connects the pores and the pores. The wet nitrogen in the pore channel enters the pore channel and is released from the pores. The pore diameter of the pore is 2 mm, and the interval between adjacent pores is 4 mm.

[0030] Example 2

[0031] like Figure 1As shown, a nylon 6 small molecule removal device comprises a removal container 1 and a devolatilization assembly 2 arranged in the removal container, the removal container is a horizontal reaction container, the removal container comprises a shell 101, a driving member 102 arranged on the shell, an exhaust hole 103 arranged on the top of the shell, a melt inlet 104 arranged on the bottom of the shell, and a melt outlet 105 arranged on the bottom of the shell, and the driving member is a driving motor;

[0032] like Figure 2 As shown, the devolatilization assembly includes a rotating shaft 201 and four devolatilization parts 202 sleeved on the rotating shaft, the interval between the devolatilization parts is 5 cm, the rotating shaft is a hollow rotating shaft with a rotating shaft channel inside, one end of the rotating shaft is detachably connected to a driving motor, the driving motor drives the rotating shaft to rotate, and the other end of the rotating shaft is connected to a wet nitrogen device, and the wet nitrogen device can pass wet nitrogen into the rotating shaft airway;

[0033] Four devolatilizers are arranged at intervals on the rotating shaft. The devolatilizer is in a circular ring shape. Three support bodies are arranged on the inner ring of the devolatilizer. The support bodies are sleeved on the rotating shaft. A channel is arranged in the support body. The channel is connected with the rotating shaft air channel. After the wet nitrogen enters the rotating shaft air channel, it can continue to pass into the channel. The devolatilizer is provided with a plurality of pores 221 and a plurality of devolatilizer holes 223 arranged along the annular ring surface. The inner diameter of the devolatilizer hole is 4 mm, and the interval between adjacent devolatilizer holes is 9 mm. A pore channel 222 is arranged inside the devolatilizer. The pore channel connects the pores and the pores. The wet nitrogen in the pore channel enters the pore channel and is released from the pores. The pore diameter of the pore is 0.1 mm, and the interval between adjacent pores is 0.2 mm.

[0034] Example 3

[0035] like Figure 1 As shown, a nylon 6 small molecule removal device comprises a removal container 1 and a devolatilization assembly 2 arranged in the removal container, the removal container is a horizontal reaction container, the removal container comprises a shell 101, a driving member 102 arranged on the shell, an exhaust hole 103 arranged on the top of the shell, a melt inlet 104 arranged on the bottom of the shell, and a melt outlet 105 arranged on the bottom of the shell, and the driving member is a driving motor;

[0036] like Figure 2 As shown, the devolatilization assembly includes a rotating shaft 201 and four devolatilization parts 202 sleeved on the rotating shaft, the interval between the devolatilization parts is 6 cm, the rotating shaft is a hollow rotating shaft with a rotating shaft channel inside, one end of the rotating shaft is detachably connected to a driving motor, the driving motor drives the rotating shaft to rotate, and the other end of the rotating shaft is connected to a wet nitrogen device, and the wet nitrogen device can pass wet nitrogen into the rotating shaft airway;

[0037] Four devolatilizers are arranged at intervals on the rotating shaft. The devolatilizer is in a circular ring shape. Three support bodies are arranged on the inner ring of the devolatilizer. The support bodies are sleeved on the rotating shaft. A channel is arranged in the support body. The channel is connected with the rotating shaft air channel. After the wet nitrogen enters the rotating shaft air channel, it can continue to pass into the channel. The devolatilizer is provided with a plurality of pores 221 and a plurality of devolatilizer holes 223 arranged along the annular ring surface. The inner diameter of the devolatilizer hole is 5 mm, and the interval between adjacent devolatilizer holes is 10 mm. A pore channel 222 is arranged inside the devolatilizer. The pore channel connects the pores and the pores. The wet nitrogen in the pore channel enters the pore channel and is released from the pores. The pore diameter of the pore is 5 mm, and the interval between adjacent pores is 10 mm.

[0038] Embodiment 4:

[0039] like Figure 1 As shown, a nylon 6 small molecule removal device comprises a removal container 1 and a devolatilization assembly 2 arranged in the removal container, the removal container is a horizontal reaction container, the removal container comprises a shell 101, a driving member 102 arranged on the shell, an exhaust hole 103 arranged on the top of the shell, a melt inlet 104 arranged on the bottom of the shell, and a melt outlet 105 arranged on the bottom of the shell, and the driving member is a driving motor;

[0040] like Figure 2 As shown, the devolatilization assembly includes a rotating shaft 201 and four devolatilization parts 202 sleeved on the rotating shaft, the interval between the devolatilization parts is 10 cm, the rotating shaft is a hollow rotating shaft with a rotating shaft channel inside, one end of the rotating shaft is detachably connected to a driving motor, the driving motor drives the rotating shaft to rotate, and the other end of the rotating shaft is connected to a wet nitrogen device, and the wet nitrogen device can pass wet nitrogen into the rotating shaft airway;

[0041] Four devolatilizers are arranged at intervals on the rotating shaft. The devolatilizer is in a circular ring shape. Three support bodies are arranged on the inner ring of the devolatilizer. The support bodies are sleeved on the rotating shaft. A channel is arranged in the support body. The channel is connected with the rotating shaft air channel. After the wet nitrogen enters the rotating shaft air channel, it can continue to pass into the channel. The devolatilizer is provided with a plurality of pores 221 and a plurality of devolatilizer holes 223 arranged along the annular ring surface. The inner diameter of the devolatilizer hole is 5 mm, and the interval between adjacent devolatilizer holes is 10 mm. A pore channel 222 is arranged inside the devolatilizer. The pore channel connects the pores and the pores. The wet nitrogen in the pore channel enters the pore channel and is released from the pores. The pore diameter of the pore is 10 mm, and the interval between adjacent pores is 20 mm.

[0042] Embodiment 5:

[0043] like Figure 1As shown, a nylon 6 small molecule removal device comprises a removal container 1 and a devolatilization assembly 2 arranged in the removal container, the removal container is a horizontal reaction container, the removal container comprises a shell 101, a driving member 102 arranged on the shell, an exhaust hole 103 arranged on the top of the shell, a melt inlet 104 arranged on the bottom of the shell, and a melt outlet 105 arranged on the bottom of the shell, and the driving member is a driving motor;

[0044] like Figure 2 As shown, the devolatilization assembly includes a rotating shaft 201 and four devolatilization parts 202 sleeved on the rotating shaft, the interval between the devolatilization parts is 8 cm, the rotating shaft is a hollow rotating shaft with a rotating shaft channel inside, one end of the rotating shaft is detachably connected to a driving motor, the driving motor drives the rotating shaft to rotate, and the other end of the rotating shaft is connected to a wet nitrogen device, and the wet nitrogen device can pass wet nitrogen into the rotating shaft airway;

[0045] Four devolatilizers are arranged at intervals on the rotating shaft. The devolatilizer is in a circular ring shape. Three support bodies are arranged on the inner ring of the devolatilizer. The support bodies are sleeved on the rotating shaft. A channel is arranged in the support body. The channel is connected with the air channel of the rotating shaft. After the wet nitrogen enters the air channel of the rotating shaft, it can continue to pass into the channel. The devolatilizer is provided with a plurality of pores 221 and a plurality of devolatilizer holes 223 arranged along the annular ring surface. The inner diameter of the devolatilizer hole is 5 mm, and the interval between adjacent devolatilizer holes is 10 mm. A pore channel 222 is arranged inside the devolatilizer. The pore channel connects the pores and the pores. The wet nitrogen in the pore channel enters the pore channel and is released from the pores. The pore diameter of the pore is 8 mm, and the interval between adjacent pores is 16 mm.

[0046] Embodiment 6:

[0047] like Figure 3 As shown, the nylon 6 small molecule removal device in Example 1 is connected in series, the nylon 6 small molecule removal device at the front end is used as the hydrothermal removal group 3, and the nylon 6 small molecule removal device at the rear end is used as the post-removal group 4. The removal process includes the following steps: the nylon 6 melt is introduced from the melt inlet of the hydrothermal removal group, 10wt% wet nitrogen is introduced from the wet nitrogen device into the rotating shaft, the driving motor is started, the driving motor drives the rotating shaft to rotate, the rotating shaft drives the devolatilization part to rotate, the wet nitrogen in the rotating shaft enters the support body and the pore channel in turn and then sprays out from the pores, the removed small molecule impurities are discharged from the exhaust hole and collected, the nylon 6 melt with small molecule impurities removed is discharged from the melt outlet and enters the post-removal group, the post-removal group does not pass wet nitrogen, and the other conditions are the same as the hydrothermal removal group. After the post-removal is completed, the nylon 6 melt enters the subsequent process device.

[0048] Embodiment 7:

[0049] like Figure 4As shown, the nylon 6 small molecule removal device in Example 1 is used for parallel and series combination, the two nylon 6 small molecule removal devices at the front end are connected in parallel as a hydrothermal removal group 3, and the nylon 6 small molecule removal device at the rear end is used as a rear removal group 4, the front end hydrothermal removal group 3 and the rear end rear removal group 4 are connected in series, and the removal process includes the following steps: the two parallel nylon 6 small molecule removal devices are used to remove small molecule impurities in the nylon 6 melt separately, the nylon 6 melt is introduced into the melt inlet of the hydrothermal removal group, and 10wt% wet nitrogen is introduced into the melt inlet of the hydrothermal removal group. The wet nitrogen device is introduced into the rotating shaft, and the driving motor is started. The driving motor drives the rotating shaft to rotate, and the rotating shaft drives the devolatilization part to rotate. The wet nitrogen in the rotating shaft enters the support body and the pore channel in turn and is ejected from the pores. The removed small molecular impurities are discharged from the exhaust holes and then collected uniformly. The nylon 6 melt with small molecular impurities removed is discharged from the melt outlets of the two parallel nylon 6 small molecule removal devices and enters the post-removal group together. No wet nitrogen is passed through the post-removal group, and the other conditions are the same as those of the hydrothermal removal group. After the post-removal is completed, the nylon 6 melt enters the subsequent process device.

[0050] By testing the small molecules of nylon 6 polyester prepared in Example 6 and Example 7, it was found that the content of hot water extractables in the nylon 6 polyester prepared in Example 4 and Example 5 was less than 3%. It can be seen that the nylon 6 small molecule removal device provided in the present application can reduce the content of hot water extractable small molecules in the nylon 6 polyester melt to less than 3% in the pretreatment stage, which can reduce the subsequent fine removal efficiency of nylon 6 small molecules. In addition, the present application uses wet nitrogen for removal, which significantly reduces energy consumption and water demand.

Claims

1. A nylon 6 small molecule removal device, characterized in that: The invention comprises a stripping container (1) and a stripping assembly (2) arranged in the stripping container, wherein the stripping assembly comprises a rotating shaft (201), a plurality of stripping parts (202) sleeved on the rotating shaft, the stripping parts are provided with a plurality of air holes (221) connected to the rotating shaft, the cross section of the stripping parts is a circular ring, an air hole channel (222) is provided inside the stripping parts, the air hole channel is connected to the rotating shaft, a plurality of stripping holes (223) are also provided on the outer edge of the stripping parts, the stripping parts are further provided with a support body (203), the support body is connected to the air holes and the rotating shaft, a hole channel (231) is provided inside the support body, the hole channel is connected to the air holes and the rotating shaft, a rotating shaft hole channel (211) is provided inside the rotating shaft, and the rotating shaft hole channel is connected to a wet nitrogen device.

2. A nylon 6 small molecule removal device according to claim 1, characterized in that: The pores have a diameter of 0.1 to 10 mm.

3. A nylon 6 small molecule removal device according to claim 1, characterized in that: The interval between the pore and its adjacent pore is 0.2-20 mm.

4. A nylon 6 small molecule removal device according to claim 1, characterized in that: The aperture of the devolatilization hole is 4-5 mm.

5. A nylon 6 small molecule removal device according to claim 1, characterized in that: The interval between the devolatilization hole and its adjacent devolatilization hole is 9-10 mm.

6. A nylon 6 small molecule removal device according to claim 1, characterized in that: The interval between the devolatilizer and the adjacent devolatilizer is 5-10 cm.

7. A nylon 6 small molecule removal device according to claim 1, characterized in that: The removal container comprises a shell (101), a driving member (102) arranged on the shell, an exhaust hole (103) arranged on the top of the shell, a melt inlet (104) arranged on the bottom of the shell, and a melt outlet (105) arranged on the bottom of the shell.

8. A nylon 6 small molecule removal device according to claim 7, characterized in that: The driving member is detachably connected to the rotating shaft.

9. The nylon 6 small molecule removal device according to claim 1, characterized in that: The removal container is a horizontal reaction container, and the devolatilizer is vertically arranged in the horizontal reaction container.

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