CN106192034A - A kind of island spinning spinning pack and utilize its preparation method preparing ultrafine carbon fiber - Google Patents

Abstract

The invention discloses a sea-island spinning spinneret assembly and a method for preparing superfine carbon fibers by using the spinneret assembly, which relates to the preparation method of the spinneret assembly and the ultrafine fiber. It is to solve the technical problem of low strength of the existing carbon fiber. The island component spinning and spinning assembly includes the island component pool, the island component outlet tube, the sea component pool, the sea component outlet tube and the sea island synthesizer; the island component outlet tube extends into the sea component outlet tube And the center line coincides, and the silk outlet pipe of the island component and the silk outlet pipe of the sea component are placed in the sea-island synthesizer. The method of preparing ultra-fine carbon fiber: dissolve polyacrylonitrile and add it to the island component pool, add polymethyl methacrylate to the sea component pool, spin, enter the coagulation bath after being drawn in the air, and then carry out Stretching at room temperature and high temperature, then removing the sea component, and finally pre-oxidizing and carbonizing to obtain ultra-fine carbon fibers. The ultra-fine carbon fiber of the present invention has a tensile strength higher than 6.6GPa and a tensile modulus higher than 324GPa. Can be used in aerospace, automotive, construction and chemical fields.

Description

A sea-island spinning spinneret assembly and its preparation method for preparing ultra-fine carbon fibers

technical field

The invention relates to a spinning assembly and a preparation method of superfine fibers.

Background technique

Microfibers generally refer to fibers with a single fiber fineness below 0.55dtex. Compared with conventional fineness fibers, superfine fibers have unparalleled advantages. The smaller the single fiber fineness, the lower the bending strength of the fiber, the better the drapability, and the softer the fabric feels; at the same time, the finer the fiber, the larger the specific surface area, and a series of properties related to the fiber diameter, such as the adsorption of the fiber. will increase accordingly. At the same time, for some high-strength fibers that require high mechanical properties, the smaller the diameter of the fiber, that is, the smaller the single fiber fineness, the smaller the probability of fiber defects, and the better the mechanical properties of the fiber. The production methods of ultrafine fibers mainly include direct spinning method, composite spinning method, blended spinning method and electrospinning technology. Various spinning techniques can produce ultrafine fibers with a single fiber fineness below 0.55dtex. Among many spinning methods, composite spinning technology is favored by people, and sea-island spinning technology is an important spinning method in composite spinning. Sea-island composite fibers are also called hyperconjugate fibers or matrix fibril fibers. Sea-island fiber is a multi-component system. From the cross-section of the fiber, one component is surrounded by another component in a fine and dispersed state, as if there are many "islands" in the "sea". Its "island" component and "sea" component are continuous, dense and uniformly dispersed in the fiber axis. From the perspective of the whole fiber, it has the fineness of conventional fibers. But if you try to remove the "sea" component, you can get bundled superfine fiber bundles.

Carbon fiber is a high-performance fiber with a theoretical tensile strength of 180GPa and a tensile modulus of around 1000GPa. It has many uses in national defense and civilian fields. According to the source of carbon raw materials, it can be divided into polyacrylonitrile (PAN)-based carbon fibers, pitch-based carbon fibers, and the like. Among them, the high-performance carbon fiber produced based on PAN is one of the fastest-growing and most widely used high-performance fibers. However, the existing carbon fiber has a great loss of fiber mechanical properties due to the obvious skin-core structure, and the tensile strength of the actually obtained carbon fiber is less than one-twentieth of the theoretical value.

Contents of the invention

The present invention aims to solve the technical problem of low strength of existing carbon fibers, and provides a sea-island spinning spinneret assembly and a method for preparing superfine carbon fibers using the same.

The sea-island spinning and spinning assembly of the present invention comprises an island component pool, an island component outlet tube, a sea component pool, a sea component outlet tube, and a sea-island synthesizer; the island component outlet tube is arranged on the island component At the bottom of the pool, the sea component outlet tube is set at the bottom of the sea component pool, the island component outlet tube extends into the sea component outlet tube, and the center line of the island component outlet tube coincides with the sea component outlet tube , the upper part of the sea-island synthesizer is cylindrical, and the lower part is conical. The island component outlet tube and the sea component outlet tube are placed in the upper cylindrical chamber of the sea-island synthesizer, and the spinnerets are set at the bottom of the conical chamber of the sea-island synthesizer. hole.

Utilize the method for preparing superfine carbon fiber by island-in-the-sea spinning and spinning assembly, carry out according to the following steps:

1. Build a sea-island spinning system, in which the spinneret assembly is the above-mentioned sea-island spinning spinneret assembly;

2. Dissolve polyacrylonitrile (PAN) with dimethyl sulfoxide to prepare an island component solution with a PAN concentration of 0.10 to 0.15 g/ml, and add it to the island component pool in the sea-island spinning spinneret assembly. Polymethyl methacrylate (PMMA) is added to the sea component tank, and the discharge rate of the island component is 0.8-2cm ³ /min per hole, and the ratio of the discharge rate of the sea component to the island component is 1:( 1～3), spin under the condition that spinning speed is 80～200m/min, obtain wet spinning;

3. The wet-spun yarn spun through the spinneret is drawn in the air at a draft ratio of 3 to 5, and then enters a low-temperature methanol coagulation bath, where it is solidified into a fiber filament, and then is heated in a low-temperature methanol coagulation bath. Soak in water for 2 to 3 days to replace the solvent in the fiber to obtain the primary sea-island fiber, then draw the primary sea-island fiber in the air at room temperature with a draft ratio of 1.1 to 1.5, and then draw it in the air at a temperature of 110 to 200 ° C Multi-stage high-temperature drawing with a draw ratio of 7 to 9 under the same conditions to obtain ultrafine sea-island fibers;

Four, reciprocating the superfine island-in-the-sea fiber through the peeling agent to remove the sea component to obtain the superfine PAN precursor; wherein the peeling agent is acetone or nitromethane;

5. Pre-oxidize the superfine PAN precursor obtained in step 3 at a temperature of 150-350° C., and then carbonize at a temperature of 380-1400° C. to obtain superfine carbon fibers.

The present invention utilizes sea-island spinning and spinneret components, and adopts dry-jet wet spinning technology to spin. The so-called dry-jet wet spinning means that the material coming out of the spinneret is first drafted through the air section, and then enters the coagulation bath to solidify into filaments. The output of the spinning assembly affects the shear rate at the nozzle of the spinning solution, the spinning speed affects the spinning stress on the single fiber, and the draw ratio affects the orientation of the polymer. Adjust the process parameters during spinning, such as output volume, spinning speed, draft ratio, etc. to achieve the best working condition. The total value of the draft ratio of the fiber from the output is 23.1 to 67.5, and the single fiber fineness is spun For ultra-fine PAN precursors less than 0.01dtex, the output volume and spinning speed, that is, the exit shear rate and spinning stress have a complementary relationship. Only when the two reach the best balance, the spinning state is the best. The spun ultrafine PAN precursor is carbonized to obtain ultrafine carbon fibers with a single fiber diameter below the micron level.

The ultra-fine carbon fiber of the present invention, due to the influence of its small size, makes the fiber have less surface defects, and the skin-core structure disappears, so that the internal and external properties of the central axis of the fiber are consistent, and at the same time has the characteristics of large specific surface area, which can improve its strength and modulus , the tensile strength of the ultrafine carbon fiber prepared by the present invention is higher than 6.6GPa, and the tensile modulus is higher than 324GPa. It can be used in many fields such as aerospace, automobile, construction, chemical industry and so on.

Description of drawings

Fig. 1 is the structural representation of the sea-island spinning and spinning assembly of the present invention; Among the figure 1 is the island component tank, 2 is the island component outlet pipe, 3 is the sea component pool, 4 is the sea component outlet wire pipe, 5 It is an island synthesizer, and 6 is a spinneret hole.

Fig. 2 is the flow diagram of the island component when the sea-island spinning spinneret assembly is spinning;

Fig. 3 is the scanning electron micrograph of the superfine island-in-the-sea fiber prepared in embodiment 1;

Fig. 4 is the physical photograph of the carbon fiber prepared in embodiment 1.

detailed description

Specific embodiment one: (referring to accompanying drawing 1) the sea-island spinning and spinning assembly of the present embodiment, comprises island component pool 1, island component silk outlet tube 2, sea component pool 3, sea component silk outlet tube 4 , sea-island synthesizer 5; the island component outlet wire pipe 2 is arranged at the bottom of the island component pool 1, the sea component outlet wire pipe 4 is arranged at the bottom of the sea component pool 3, and the island component outlet wire pipe 2 extends into the sea component In the outlet pipe 4, the center line of the island component outlet pipe 2 coincides with the center line of the sea component outlet pipe 4, the upper part of the sea-island synthesizer 5 is cylindrical, and the lower part is conical, and the island component outlet pipe 2 is in line with the sea group. The branching wire pipe 4 is placed in the cylindrical chamber on the upper part of the sea-island synthesizer 5, and the spinneret hole 6 is arranged at the bottom of the conical chamber of the sea-island synthesizer.

In this embodiment, during spinning, the island component in the island component pool is input to the sea-island synthesizer through the island component outlet tube, and at the same time, the sea component in the sea component pool is input to the sea-island synthesizer through the sea component outlet tube. In the sea island synthesizer, the sea component is coated on the outside of the island component and sprayed out through the spinneret hole. This structure can make the island components continuous, and the liquid flows of the island components have no mutual influence and no adhesion, so that the island components are continuous and uniform, as shown in FIG. 2 .

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the number of wire outlet tubes of the island component is 7-37. Others are the same as in the first embodiment.

Embodiment 3: The method for preparing ultra-fine carbon fibers using the sea-island spinning and spinning assembly described in Embodiment 1 is carried out in the following steps:

1. Build a sea-island spinning system, in which the spinneret assembly is the above-mentioned sea-island spinning spinneret assembly;

2. Dissolve polyacrylonitrile (PAN) with dimethyl sulfoxide to prepare an island component solution with a PAN concentration of 0.10 to 0.15 g/ml, and add it to the island component pool in the sea-island spinning spinneret assembly. Polymethyl methacrylate (PMMA) is added to the sea component tank, and the discharge rate of the island component is 0.8-2cm ³ /min per hole, and the ratio of the discharge rate of the sea component to the island component is 1:( 1～3), spin under the condition that spinning speed is 80～200m/min, obtain wet spinning;

3. The wet-spun yarn spun through the spinneret is drawn in the air at a draft ratio of 3 to 5, and then enters a low-temperature methanol coagulation bath, where it is solidified into a fiber filament, and then is heated in a low-temperature methanol coagulation bath. Soak in water for 2 to 3 days to replace the solvent in the fiber to obtain the primary sea-island fiber, then draw the primary sea-island fiber in the air at room temperature with a draft ratio of 1.1 to 1.5, and then draw it in the air at a temperature of 110 to 200 ° C Multi-stage high-temperature drawing with a draw ratio of 7 to 9 under the same conditions to obtain ultrafine sea-island fibers;

Four, reciprocating the superfine island-in-the-sea fiber through the peeling agent to remove the sea component to obtain the superfine PAN precursor; wherein the peeling agent is acetone or nitromethane;

5. Pre-oxidize the superfine PAN precursor obtained in step 3 at a temperature of 150-350° C., and then carbonize at a temperature of 380-1400° C. to obtain superfine carbon fibers.

Embodiment 4: This embodiment differs from Embodiment 3 in that the island component solution with a PAN concentration of 0.12 g/ml in Step 2 is different. Others are the same as in the third embodiment.

Embodiment 5: The difference between this embodiment and Embodiment 3 or 4 is that the output of PAN in step 2 is 1 cm ³ /min, the ratio of the output of the sea component to the island component is 1:2, and the spinning The wire speed was 80 m/min. Others are the same as the third or fourth specific embodiment.

Specific embodiment six: the difference between this embodiment and one of the specific embodiments three to five is that the output of PAN in step 2 is 1.5cm ³ /min, and the ratio of the output of the sea component to the island component is 1: 2.5. The spinning speed is 120m/min. Others are the same as one of the third to fifth specific embodiments.

Embodiment 7: This embodiment differs from Embodiment 3 to Embodiment 6 in that the temperature of the low-temperature methanol coagulation bath in step 3 is -15°C to 0°C. Others are the same as one of the third to sixth specific embodiments.

Embodiment 8: The difference between this embodiment and one of Embodiments 3 to 7 is that the multi-stage high-temperature drafting in step 4 is three-stage to five-stage drafting. Others are the same as one of the third to seventh embodiments.

Embodiment 9: This embodiment differs from Embodiment 3 to Embodiment 8 in that the pre-oxidation temperature in step 5 is 200-250°C, and the carbonization temperature is 400-800°C. Others are the same as one of the third to eighth specific embodiments.

Verify beneficial effect of the present invention with following example:

Embodiment 1: In this embodiment, the method for preparing ultra-fine carbon fibers by sea-island spinning and spinning assembly is carried out in the following steps:

1. Build a sea-island spinning system, in which the spinner assembly is a sea-island spinning spinneret, and the sea-island spinning spinneret consists of an island component pool 1, an island component outlet tube 2, a sea component pool 3, and a sea group It is composed of a separating wire pipe 4 and a sea-island synthesizer 5; the island component wire outlet pipe 2 is arranged at the bottom of the island component pool 1, the sea component outlet wire pipe 4 is arranged at the bottom of the sea component pool 3, and the island component outlet wire 2 The pipe extends into the sea component outlet pipe 4, the center line of the island component outlet pipe 2 coincides with the sea component outlet pipe 4, the top of the island synthesizer 5 is cylindrical, and the bottom is conical, and the island component outlet The silk pipe 2 and the sea component outlet silk pipe 4 are placed in the cylindrical chamber on the upper part of the sea-island synthesizer, and the spinneret hole 6 is set at the bottom of the conical chamber of the sea-island synthesizer. The diameter of the outlet pipe of the island component is 0.3mm, the diameter of the outlet pipe of the sea component is 1.2mm, and the diameter of the spinneret hole is 0.25mm. There are 20 island component outlet tubes and 20 corresponding sea component outlet tubes in each sea-island spinneret, and two sea-island spinneret assemblies are assembled on one spinneret.

2. Dissolve polyacrylonitrile (PAN) with dimethyl sulfoxide to prepare an island component solution with a PAN concentration of 15g/100ml, add it to the island component pool in the sea-island spinning spinneret assembly, and add PMMA to the In the sea component pool, the island component output is 1.5cm ³ /min, the ratio of the sea component to the island component output is 1:2, and the spinning speed is 100m/min for spinning to obtain wet spinning;

3. The wet-spun yarn spun through the spinneret is drawn in the air at a draft ratio of 5, and then enters a low-temperature methanol coagulation bath with a temperature of -5°C, and is coagulated into fiber filaments in the coagulation bath. Then soak in low-temperature methanol for 3 days to replace the solvent in the fiber to obtain the primary island-in-the-sea fiber. The fiber is drawn in the air at room temperature with a draft ratio of 1.2, and then the primary draft is performed at 110°C. The draw ratio is 1.5, and then the secondary drawing is carried out under the condition of 140°C, the draw ratio is 2.2, and finally the third stage drawing is carried out under the condition of 180°C, the draw ratio is 3, and the superfine sea-island fiber is obtained;

4. Pass the ultra-fine island-in-the-sea fiber back and forth through the nitromethane peeling agent to remove the sea component and obtain the ultra-fine PAN precursor;

5. Pre-oxidize the ultrafine PAN precursor obtained in step 2 at a temperature of 250° C., and then carbonize at a temperature of 500° C. to obtain ultrafine carbon fibers.

The scanning electron microscope photo of the ultrafine sea-island fiber prepared in Step 3 of this embodiment is shown in Figure 3. It can be seen from Figure 3 that the "core" PAN of the ultrafine sea-island fiber is not bonded to the "skin" PMMA, and the skin-core structure is easy Separation, which is formed due to the large draft ratio of the fiber, and the spinnability is very good. It can also be seen from Figure 3 that the diameter of the fiber is about 60 microns.

The physical photo of the composite fiber prepared in this example is shown in Figure 4. Due to the easy separation of PAN and PMMA, it is feasible to prepare ultrafine fibers. Under the occupancy and protection of PMMA, the preparation of ultrafine PAN can be achieved. Realized, so that the fiber skin-core structure disappears, making the inner and outer properties of the fiber central axis consistent, which can improve its strength and modulus. The tensile strength of the ultrafine carbon fiber prepared in this embodiment is 6.8GPa, and the tensile modulus is 326GPa.

Embodiment 2: In this embodiment, the method for preparing ultra-fine carbon fibers by sea-island spinning and spinning assembly is carried out in the following steps:

1. Set up the sea-island spinning system identical to that of Example 1;

2. Dissolve polyacrylonitrile (PAN) with dimethyl sulfoxide to prepare an island component solution with a PAN concentration of 12g/100ml, add it to the island component pool in the sea-island spinning spinneret assembly, and add PMMA to the island component pool In the sea component pool, the island component output is 2cm ³ /min, the ratio of the sea component to the island component output is 1:3, and the spinning speed is 200m/min for spinning to obtain wet spinning Silk;

3. The wet-spun yarn spun through the spinneret is drawn in the air at a draft ratio of 3, and then enters a low-temperature methanol coagulation bath with a temperature of -10°C, and is coagulated into a fiber filament in the coagulation bath. Then soak in low-temperature methanol for 3 days to replace the solvent in the fiber to obtain the primary island-in-the-sea fiber. The fiber is drawn in the air at room temperature with a draft ratio of 1.2, and then the primary draft is performed at 110°C. The draw ratio is 1.1, and then the secondary drawing is carried out under the condition of 140°C, the draw ratio is 2.5, and finally the third stage drawing is carried out under the condition of 180°C, the draw ratio is 3.5, and the superfine sea-island fiber is obtained;

4. Pass the ultra-fine sea-island fiber back and forth through the acetone peeling agent to remove the sea component and obtain the ultra-fine PAN precursor;

5. Pre-oxidize the ultrafine PAN precursor obtained in step 2 at a temperature of 300° C., and then carbonize at a temperature of 700° C. to obtain ultrafine carbon fibers.

The tensile strength of the ultrafine carbon fiber prepared in this embodiment is 6.7GPa, and the tensile modulus is 325GPa.

Claims (9)

1. an island spinning spinning pack, it is characterised in that this assembly includes that component pond, island (1), island component go out fiber tube (2), sea Component pond (3), sea component go out fiber tube (4), island synthesizer (5)；Island component goes out fiber tube (2) and is arranged on bottom, component pond, island (1), Sea component goes out fiber tube (4) and is arranged on bottom, sea component pond (3), and island component goes out fiber tube (2) and stretches into sea component and go out in fiber tube (4), island Component goes out fiber tube (2) and goes out the centrage of fiber tube (4) with sea component and overlap, and island synthesizer (5) top is cylindrical, and bottom is circle Taper, island component goes out fiber tube (2) and goes out in the cylindrical cavity that fiber tube (4) is placed in island synthesizer (5) top with sea component, closes on island The bottom of the conical cavity grown up to be a useful person arranges spinneret orifice (6).

A kind of island spinning spinning pack the most according to claim 1, it is characterised in that it is 7 that island component goes out the quantity of fiber tube ～37.

3. utilize the method that the island spinning spinning pack described in claim 1 prepares ultrafine carbon fiber, it is characterised in that the party Method sequentially includes the following steps:

One, building island spinning system, spinning pack therein is the island spinning spinning pack described in claim 1；

Two, by polyacrylonitrile dmso solution, it is prepared as the island component solution that PAN concentration is 0.10～0.15g/ml, Join in the component pond, island in island spinning spinning pack, polymethyl methacrylate is joined in sea component pond, on island Component load is single hole 0.8～2cm³/ min, sea component are 1:(1～3 with the ratio of island component load), spinning speed be 80 ～spinning under conditions of 200m/min, obtain wet spinning silk；

Three, through spinning nozzle spun wet spinning silk, in atmosphere, after the draw ratio with 3～5 carries out drawing-off, enter low-temp methanol and coagulate Gu in Yu, solidificating fiber silk in coagulating bath, afterwards in low-temp methanol soak 2～3 days to displace the solvent in fiber, Obtain primary sea-island fibre, be 1.1～1.5 to carry out room temperature drawing-off with draw ratio the most in atmosphere by this primary sea-island fibre, then It is 7～9 to carry out multistage high temperature drawing-off with draw ratio under conditions of temperature is 110～200 DEG C, obtains ultra-fine sea-island fibre；

Four, ultra-fine sea-island fibre is reciprocated through decorticating agent, to remove sea component, obtain ultra-fine PAN precursor；Wherein said is de- Skin agent is acetone or nitromethane；

Five, the ultra-fine PAN precursor that step 3 is obtained pre-oxidizes, the most again in temperature under conditions of temperature is 150～350 DEG C It is carbonization under conditions of 380～1400 DEG C, obtains ultrafine carbon fiber.

The method utilizing island spinning spinning pack to prepare ultrafine carbon fiber the most according to claim 3, it is characterised in that In step 2, PAN concentration is the island component solution of 0.12g/ml.

5., according to utilizing, described in claim 3 or 4, the method that island spinning spinning pack prepares ultrafine carbon fiber, its feature exists In step 2, the load of PAN is 1cm³/ min, sea component and the ratio of island component load are 1:2, spinning speed is 80m/ min。

6., according to utilizing, described in claim 3 or 4, the method that island spinning spinning pack prepares ultrafine carbon fiber, its feature exists In step 2, in step 2, the load of PAN is 1.5cm³/ min, sea component are 1:2.5 with the ratio of island component load, spin Silk speed is 120m/min.

7., according to utilizing, described in claim 3 or 4, the method that island spinning spinning pack prepares ultrafine carbon fiber, its feature exists The temperature of the low-temp methanol coagulating bath in step 3 is-15～0 DEG C.

8., according to utilizing, described in claim 3 or 4, the method that island spinning spinning pack prepares ultrafine carbon fiber, its feature exists In step 4, multistage high temperature drawing-off is the drawing-off of three to Pyatyi.

9., according to utilizing, described in claim 3 or 4, the method that island spinning spinning pack prepares ultrafine carbon fiber, its feature exists In step 5, the temperature of pre-oxidation is 200～250 DEG C, and the temperature of carbonization is 400～800 DEG C.