CN110184674B - A kind of skin-core porous composite fiber and preparation method thereof - Google Patents

Abstract

The invention relates to a skin-core type porous composite fiber and a preparation method thereof. The preparation method comprises the following steps: soaking a skin-core type composite fiber with a hole groove and containing dissolvable inorganic particles in a solvent to obtain the skin-core type porous composite fiber; The skin-core composite fiber with holes and grooves and containing soluble inorganic particles is obtained by melting the skin layer raw materials and the core layer raw materials and spinning them through a skin-core type spinneret. There are a plurality of intersecting spokes in the hole, and the spokes are mainly located in the core layer through hole, and one of the spokes is connected to the inner wall of the skin layer through hole; the solvent can only dissolve the skin-core composite fiber with hole grooves and containing soluble inorganic particles. Inorganic particles; the final skin-core composite fiber is a skin-core porous composite fiber, and holes are distributed in the core layer, and the average diameter of the holes is 100-5000 nm. The skin-core porous composite fiber prepared by the invention has the advantages of high specific surface area and can be applied to the fields of heat insulation, sound insulation and the like.

Description

A kind of skin-core porous composite fiber and preparation method thereof

technical field

The invention belongs to the technical field of composite fibers, and relates to a skin-core porous composite fiber and a preparation method thereof.

Background technique

At present, fibers are widely used in various fields such as textiles, medical care, safety protection, packaging, electronic appliances and environmental protection. With the progress of society and the continuous improvement of people's living standards, people's demand for functionalization and differentiation of fibers is increasing. Come higher.

Fiber materials are widely used, but the properties of fiber materials are simultaneously affected by specific surface area, surface energy and surface activity, which greatly reduces the application effect. The excellent properties of high specific surface area and surface energy, low relative density, and low mass brought by the porous structure make porous fibers perform well in the fields of sound insulation, heat insulation, filtration, drug delivery, biomaterials, and construction. The porous structure of porous fibers not only provides excellent special properties for fibers, but also brings disadvantages such as poor mechanical properties and narrow application fields.

The skin-core composite fiber is composed of two components of the skin layer and the core layer. The composite fiber has the respective performance advantages of the two components, giving more performance combinations and promoting the development of fiber differentiation. At present, the widely used skin-core composite fibers in the market are mainly hollow fibers, ultra-fine fibers, artificial wool and refractory fibers. Due to their strong flexibility and excellent mechanical properties, skin-core composite fibers are being widely used in various fields. .

The skin-core composite fiber can make the fiber have different functions through the different distribution of the two components on the cross-section of the composite fiber. If the skin-core porous composite fiber can be prepared, it is expected to solve the problem of poor mechanical properties of the current porous fiber.

Therefore, it is of great significance to study a skin-core porous composite fiber with better mechanical properties to expand the application field of porous fibers.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem in the prior art that the mechanical properties of porous fibers are poor and lead to a narrow application field, and provide a skin-core porous composite fiber and a preparation method thereof. The invention preserves the integrity of the skin structure of the skin-core composite fiber, and the skin acts as a mechanical support to ensure that the fiber has excellent mechanical properties. Fields of application of porous fibers.

For achieving the above object, the scheme that the present invention adopts is as follows:

A method for preparing a skin-core type porous composite fiber. The skin-core composite fiber of the particles is obtained by melting the skin-layer raw materials and the core-layer raw materials and spinning them through a skin-core type spinneret. The soluble inorganic particles at the silk temperature and the core layer polymer are composed of the core layer polymer. There are more than one intersecting spokes, the spokes are solid long bars, the length direction is perpendicular to the axial direction of the spinneret hole, the spokes are mainly located in the core layer through holes, and one of the spokes is connected to the inner wall of the skin layer through holes;

The solvent is a good solvent for dissolving inorganic particles, and a non-good solvent for the core layer polymer and the skin layer polymer;

Spokes are arranged in the spinneret holes, and the melt will form holes with the same number, size and position as the spokes when extruded from the spinneret holes. Since one of the spokes is connected to the inner wall of the cortex through-hole, the notch of a hole in the fiber will be formed. It is located on the surface of the skin-core composite fiber, and the solvent can enter the fiber from this position. Since the spokes intersect, the holes and grooves in the fiber are connected with each other, and the solvent can enter all the holes and grooves;

When the skin-core composite fiber with holes and soluble inorganic particles is soaked in a solvent, the solvent enters the fiber through the holes and grooves, and can dissolve the skin with holes and soluble inorganic particles under heating or non-heating conditions. The inorganic particles in the core layer of the core composite fiber do not damage the skin layer; after the dissolvable particles in the core layer are dissolved, a skin-core composite fiber with a porous core layer with evenly distributed pores can be obtained. It can ensure certain mechanical properties of the composite fiber. The existence of porous structure makes the fiber have the advantages of light weight, heat insulation, heat preservation, noise reduction, etc., and the distribution of the fiber skin-core polymer can make the fiber have a three-dimensional crimped structure.

As a preferred solution:

In the above-mentioned preparation method of the skin-core porous composite fiber, the cross-sections of the spinneret hole and the core layer through hole are circular, and the diameters are respectively 5-150 μm and 1-100 μm.

The above-mentioned preparation method of a skin-core porous composite fiber, the number of spokes is 3 to 5, the spokes intersect at one point, and the whole is radially distributed, and the intersection points are square, circular, triangular, prismatic, Y-shaped Or * type, the equivalent diameter is 0.1～50μm, the length of the spoke is 0.5～50μm from the intersection of the spoke to the end of the spoke, the width of the spoke is the dimension perpendicular to the length direction of the spoke in the spinneret cross-section is 0.1～10μm .

In the above-mentioned preparation method of the skin-core porous composite fiber, the skin through holes are tangent to the core through holes, one spoke is connected to the inner wall of the skin through holes at the tangent point, and the other spokes are integrally located in the core through holes.

The above-mentioned preparation method of a skin-core porous composite fiber, the core layer raw material is prepared by melt-blending the core layer polymer and the soluble inorganic particles; the core layer polymer and the soluble inorganic particles in the core layer raw material The mass ratio of particles is 99:1 to 70:30.

In the above-mentioned preparation method of a skin-core porous composite fiber, before spinning, each component is vacuum-dried at a temperature of 80-180° C. for 10-20 hours;

During spinning, the mass ratio of the raw materials of the skin layer and the raw materials of the core layer is 7:3 to 3:7;

Spinning process parameters are: spinning temperature is 200～350℃, spinning temperature fluctuation range is ±1℃, spinning pressure is 6～50MPa, draft ratio is 1～5 times, spinning speed is 1000～6000m/ min.

In the above-mentioned preparation method of the skin-core porous composite fiber, the soaking temperature is 25-100° C., and the time is 2-24 hours.

The above-mentioned preparation method of a skin-core porous composite fiber, the material of the skin layer polymer and the core layer polymer are different; the skin layer polymer is polyethylene, polyphenylene sulfide, polyester, polylactic acid, polyacrylonitrile and More than one kind of polyamide; core layer polymer is more than one kind of polypropylene, polyester, polyacrylonitrile, polyamide and polyvinylidene fluoride; soluble inorganic particles are sodium chloride, potassium chloride, chlorine more than one of ammonium sulfate, ammonium sulfate, potassium sulfate and sodium sulfate; the solvent is water.

The skin-core porous composite fiber prepared by the method for preparing a skin-core porous composite fiber according to any one of the above is a skin-core composite fiber, and holes are distributed in the core layer.

The above-mentioned skin-core porous composite fiber has an average diameter of 100-5000 nm of pores, a breaking strength of the skin-core porous composite fiber 2.2-4.0 cN/dtex, and a breaking elongation of 15%-60%.

Beneficial effects:

(1) In a method for preparing a skin-core porous composite fiber of the present invention, the dissolvable inorganic particles in the core layer are selected from easily soluble and non-polluting inorganic substances such as sodium chloride, and such inorganic substances can be easily dissolved in pure water. Dissolving, the process is simple, the cost is low, and the dissolution rate of the particles in the fiber core layer can be controlled by adjusting the dissolution time and temperature;

(2) A preparation method of a skin-core porous composite fiber of the present invention, by forming a porous structure in the core layer part, compared with the traditional fiber, the skin-core porous composite fiber has a larger surface area, and the structure of the skin layer It can also ensure the mechanical properties of the fiber;

(3) A kind of skin-core porous composite fiber prepared by the method of the present invention has excellent three-dimensional crimping performance macroscopically due to the existence of thermal shrinkage and stress difference between the two components;

(4) A skin-core porous composite fiber prepared by the method of the present invention has wide application fields, and can be used for disposable filter materials, sound insulation, heat insulation materials, and the like.

Description of drawings

Fig. 1 is a cross-sectional view of a sheath-core composite fiber with a slot and containing sodium chloride;

Figure 2 is a cross-sectional view of a skin-core porous composite fiber;

3 is a cross-sectional view of a spinneret hole of a skin-core spinneret;

Among them, 1-skin layer, 2-core layer, 3-sodium chloride, 4-hole slot, 5-hole slot center, 6-hole, 7-spoke, 8-skin through hole, 9-core through hole.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of core layer raw materials: put polypropylene and sodium chloride with a mass ratio of 99:1 into an internal mixer or twin screw for melt blending, and mix evenly to obtain core layer raw materials;

(2) prepare the sheath-core composite fiber with perforated grooves and containing sodium chloride: put the skin layer raw material polyethylene and the core layer raw material into the melt composite spinning machine, and obtain by spinning through the sheath-core type spinneret after melting; The cross section of the skin-core composite fiber with hole grooves and containing sodium chloride is shown in Figure 1. The skin-core composite fiber is a skin-core structure, the skin layer 1 wraps the core layer 2, the sodium chloride 3 is distributed in the core layer 2, and the pores The groove 4 is mainly located in the core layer 2, and the center 5 part of the hole groove is a hollow circle; The mass ratio of the core layer raw materials is 7:3; the spinning process parameters are: the spinning temperature is 200°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 6MPa, the draft ratio is 1 times, and the spinning speed is is 1000m/min;

As shown in Figure 3, the cross-section of the spinneret hole of the skin-core spinneret is circular, with a diameter of 5 μm. The parts of the spinneret hole for the skin layer raw materials and the core layer raw materials to pass through are the skin layer through holes 8 and the core layer respectively. The through hole 9, the through hole 8 of the skin layer and the through hole 9 of the core layer are tangent, the cross section of the through hole 9 of the core layer is circular, the diameter is 1 μm, there are 3 spokes in the spinneret hole, and the spoke 7 is a solid long strip, The length direction is perpendicular to the axis of the spinneret hole, the spokes are mainly located in the core layer through hole 9, and one spoke is connected to the inner wall of the skin layer through hole 8 at the tangent point between the skin layer through hole 8 and the core layer through hole 9, and the other spokes are integral It is located in the through hole 9 of the core layer; the spokes intersect at one point, and the overall distribution is radial, the intersection is square, the equivalent diameter is 0.1 μm, the width of each spoke is 0.1 μm, and the length is 0.5 μm;

(3) Dissolving the fiber core layer to prepare the skin-core porous composite fiber: soak the prepared skin-core composite fiber with a hole groove and containing sodium chloride in water, and use the fiber hole groove to immerse the water into the fiber. Soak for 24 hours at a temperature of 25°C to dissolve the sodium chloride in the core layer. After the sodium chloride in the core layer is dissolved, a skin-core composite fiber with a porous core layer with evenly distributed pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber. As shown in Figure 2, there are holes 6 distributed in the core layer, the average diameter of the holes is 100nm, and the breaking strength of the skin-core porous composite fiber is 2.2cN /dtex, elongation at break 15%.

Example 2

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) prepare core layer raw material: put polyester and potassium chloride in a mass ratio of 90:10 into an internal mixer or twin screw for melt blending, and mix evenly to obtain core layer raw material;

(2) Preparation of sheath-core composite fibers with perforated grooves and potassium chloride: the skin layer raw material polyphenylene sulfide and the core layer raw materials are put into a melt composite spinning machine, and after melting, they are spun through a sheath-core type spinneret. Obtained; before spinning, the components of the skin layer and the core layer were vacuum-dried for 10 hours at a temperature of 160 °C; during spinning, the mass ratio of the skin layer raw materials and the core layer raw materials was 7:3; the spinning process parameters were: The spinning temperature is 350°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 20MPa, the draft ratio is 2 times, and the spinning speed is 2000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular, with a diameter of 45 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 30μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axial direction of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection is circular, the equivalent diameter is 5μm, the width of each spoke is 2μm, and the length is 6μm;

(3) Dissolving the fiber core layer to prepare the skin-core type porous composite fiber: soak the prepared skin-core type composite fiber with hole grooves and potassium chloride in water, and use the fiber hole groove to immerse the water into the fiber. Soak for 10 hours at 50°C to dissolve potassium chloride in the core layer. After the potassium chloride in the core layer is dissolved, a skin-core composite fiber with a porous core layer with evenly distributed pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber, and holes are distributed in the core layer, the average diameter of the holes is 500nm, the breaking strength of the skin-core porous composite fiber is 3.5cN/dtex, and the elongation at break is 3.5cN/dtex. was 36%.

Example 3

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of core layer raw materials: put polyacrylonitrile and ammonium chloride in a mass ratio of 70:30 into an internal mixer or twin-screw for melt blending, and mix evenly to obtain core layer raw materials;

(2) prepare the sheath-core composite fiber with perforated grooves and containing ammonium chloride: put the skin layer raw material polyester and the core layer raw material into the melt composite spinning machine, and obtain by spinning through the sheath-core type spinneret after melting; Before spinning, the components of the skin layer and the core layer were vacuum-dried at a temperature of 180°C for 12 hours; during spinning, the mass ratio of the skin layer raw materials and the core layer raw materials was 3:7; the spinning process parameters were: spinning The temperature is 280°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 20MPa, the draft ratio is 2.5 times, and the spinning speed is 6000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 150 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 100μm, there are 4 spokes in the spinneret hole, the spokes are solid long, and the length direction is perpendicular to the axis of the spinneret hole. Located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point between the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radially distributed , the intersection is a triangle, the equivalent diameter is 50 μm, the width of each spoke is 10 μm, and the length is 50 μm;

(3) Preparation of skin-core porous composite fibers by dissolving the fiber core layer: soaking the prepared skin-core composite fibers with hole grooves and containing ammonium chloride in water, and using the fiber hole grooves to immerse water into the inside of the fibers. Soaking for 8 hours at a temperature of 100°C dissolves the ammonium chloride in the core layer. After the ammonium chloride in the core layer is dissolved, a skin-core composite fiber with a porous core layer with evenly distributed pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber. There are holes distributed in the core layer, and the average diameter of the holes is 5000nm. The breaking strength of the skin-core porous composite fiber is 1.8cN/dtex, and the elongation at break is 60%.

Example 4

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of core layer raw materials: put polypropylene and ammonium sulfate with a mass ratio of 80:20 into an internal mixer or twin-screw for melt blending, and mix evenly to obtain core layer raw materials;

(2) Preparation of skin-core composite fiber with hole grooves and containing ammonium sulfate: the skin layer raw material polylactic acid and the core layer raw material are put into a melt composite spinning machine, and after melting, they are obtained by spinning through a skin-core type spinneret; Before spinning, the components of the skin layer and the core layer were vacuum-dried at a temperature of 100 °C for 12 hours; during spinning, the mass ratio of polylactic acid and core layer raw materials was 5:5; the spinning process parameters were: spinning temperature is 250°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 50MPa, the draft ratio is 3 times, and the spinning speed is 3000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 50 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole respectively. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 50μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axial direction of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection is prismatic, the equivalent diameter is 20μm, the width of each spoke is 5μm, and the length is 2μm;

(3) Preparation of skin-core porous composite fibers by dissolving the fiber core layer: soak the prepared skin-core composite fibers with holes and ammonium sulfate in water, and use the fiber holes to soak water into the fibers. After soaking for 2 hours at the temperature of ℃, the ammonium sulfate in the core layer is dissolved. After the ammonium sulfate in the core layer is dissolved, a skin-core composite fiber with a porous core layer with uniform pores can be obtained.

The final obtained skin-core porous composite fiber is a skin-core composite fiber, and holes are distributed in the core layer, the average diameter of the holes is 1000nm, the breaking strength of the skin-core porous composite fiber is 3.6cN/dtex, and the elongation at break is 3.6cN/dtex 30%.

Example 5

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) prepare core layer raw material: put polyamide and potassium sulfate with a mass ratio of 70:30 into an internal mixer or twin-screw for melt blending, and mix uniformly to obtain core layer raw material;

(2) Preparation of sheath-core composite fibers with perforated grooves and potassium sulfate: the mixture of polypropylene, polylactic acid and polyester with a skin layer raw material molar ratio of 1:1:1 and the core layer raw materials are put into melt composite spinning In the machine, it is obtained by spinning through a skin-core spinneret after melting; before spinning, the components of the skin layer and core layer are vacuum-dried at a temperature of 100 ° C for 18 hours; during spinning, the skin layer raw materials and the core layer raw materials The mass ratio is 3:7; the spinning process parameters are: the spinning temperature is 250°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 10MPa, the draft ratio is 4 times, and the spinning speed is 2000m/ min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 150 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 60μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axial direction of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection is Y-shaped, the equivalent diameter is 20μm, the width of each spoke is 5μm, and the length is 10μm;

(3) Preparation of skin-core porous composite fibers by dissolving the fiber core layer: soaking the prepared skin-core composite fibers with perforated grooves and potassium sulfate in water, and using the fiber perforated grooves to immerse water into the fibers, at 80 °C After soaking for 8 hours at the temperature of ℃, the potassium sulfate in the core layer is dissolved. After the potassium sulfate in the core layer is dissolved, a skin-core composite fiber with a porous core layer with uniform pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber, the core layer is distributed with holes, the average diameter of the holes is 2000nm, the breaking strength of the skin-core porous composite fiber is 3.2cN/dtex, and the elongation at break is 3.2cN/dtex. was 28%.

Example 6

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of core layer raw materials: Put polyvinylidene fluoride and a mixture of potassium sulfate and sodium sulfate with a mass ratio of 1:1 into an internal mixer or twin screw according to a mass ratio of 95:5 for melt blending, and mix evenly to obtain the core layer raw material;

(2) Preparation of sheath-core composite fiber with perforated grooves and containing potassium sulfate and sodium sulfate: the skin layer raw material polyamide and the core layer raw material are put into the melt composite spinning machine, and they are spun through the sheath-core type spinneret after melting. Obtained; before spinning, the components of the skin layer and the core layer were vacuum-dried at a temperature of 120 ° C for 12 hours; during spinning, the mass ratio of the raw materials of the polyamide and the core layer was 7:3; the spinning process parameters were: The spinning temperature is 250°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 20MPa, the draft ratio is 5 times, and the spinning speed is 3000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 50 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole respectively. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 20μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axis of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection point is * type, the equivalent diameter is 20μm, the width of each spoke is 5μm, and the length is 10μm;

(3) Dissolving the fiber core layer to prepare the skin-core type porous composite fiber: soak the prepared skin-core type composite fiber with a hole groove and containing potassium sulfate and sodium sulfate in water, and use the fiber hole groove to immerse the water inside the fiber , soaked at 70 ℃ for 2 hours to dissolve potassium sulfate and sodium sulfate in the core layer. After the potassium sulfate and sodium sulfate in the core layer are dissolved, a skin-core composite fiber with a porous core layer with uniform pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber. There are holes distributed in the core layer, and the average diameter of the holes is 500 nm. The breaking strength of the skin-core porous composite fiber is 3.6cN/dtex, and the elongation at break was 52%.

Example 7

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of core layer raw materials: put the mixture of polyvinylidene fluoride and polyethylene with a molar ratio of 1:1 and sodium sulfate into an internal mixer or twin screw according to a mass ratio of 95:5 for melt blending, and mix evenly to obtain the core layer raw material;

(2) Preparation of a sheath-core composite fiber with perforated grooves and containing sodium sulfate: the mixture of polyamide and polyester with a skin layer raw material molar ratio of 1:1 and the core layer raw materials are put into a melt composite spinning machine, and after melting It is obtained by spinning through a skin-core spinneret; before spinning, the skin layer is vacuum-dried at a temperature of 120 °C for 12 hours, and the core layer is vacuum-dried at a temperature of 80 °C for 12 hours; during spinning, the skin layer raw material The mass ratio of the raw material to the core layer is 7:3; the spinning process parameters are: the spinning temperature is 210°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 20MPa, the draft ratio is 2.5 times, and the spinning The speed is 3000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 50 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole respectively. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 20μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axis of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection point is * type, the equivalent diameter is 20μm, the width of each spoke is 5μm, and the length is 10μm;

(3) Dissolving the fiber core layer to prepare the skin-core porous composite fiber: soak the prepared skin-core composite fiber with a hole groove and containing sodium sulfate in water, and use the fiber hole groove to immerse the water into the fiber. After soaking for 24 hours at a temperature of ℃, the sodium sulfate in the core layer is dissolved. After the sodium sulfate in the core layer is dissolved, a skin-core composite fiber with a porous core layer with uniform pores can be obtained.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber, and holes are distributed in the core layer, the average diameter of the holes is 800nm, the breaking strength of the skin-core porous composite fiber is 2.5cN/dtex, and the breaking elongation is is 50%.

Example 8

A preparation method of a skin-core porous composite fiber, the main steps are as follows:

(1) Preparation of raw materials for the core layer: a mixture of polyvinylidene fluoride, polyamide and polypropylene with a molar ratio of 1:1:1 and a mixture of sodium sulfate, ammonium sulfate and ammonium chloride with a mass ratio of 1:1:1 The mixture is put into an internal mixer or twin-screw according to the mass ratio of 95:5 for melt blending, and the core layer raw materials are obtained by mixing evenly;

(2) Preparation of a sheath-core composite fiber with perforated grooves and containing sodium sulfate, ammonium sulfate and ammonium chloride: the skin layer raw material polyamide and the core layer raw material are put into the melt composite spinning machine, and after melting, the sheath-core type is sprayed through the core layer. It is obtained by spinning the silk plate; before spinning, the components of the skin layer and the core layer are vacuum-dried at a temperature of 100 ° C for 12 hours; during spinning, the mass ratio of the raw materials of the polyamide and the core layer is 7:3; spinning The process parameters are: the spinning temperature is 210°C, the spinning temperature fluctuation range is ±1°C, the spinning pressure is 20MPa, the draft ratio is 5 times, and the spinning speed is 3000m/min;

The cross-section of the spinneret hole of the skin-core type spinneret is circular and the diameter is 50 μm. The parts of the spinneret hole for the skin layer raw material and the core layer raw material to pass through are respectively the skin layer through hole and the core layer through hole, the skin layer through hole and the core layer through hole respectively. The core layer through hole is tangent, the cross section of the core layer through hole is circular, the diameter is 20μm, there are 5 spokes in the spinneret hole, the spokes are solid long bars, the length direction is perpendicular to the axis of the spinneret hole, the spokes Mainly located in the core layer through hole, one of the spokes is connected to the inner wall of the skin layer through hole at the tangent point of the skin layer through hole and the core layer through hole, and the other spokes are located in the core layer through hole as a whole; the spokes intersect at one point, and the whole is radial Distribution, the intersection point is * type, the equivalent diameter is 20μm, the width of each spoke is 5μm, and the length is 10μm;

(3) Preparation of skin-core porous composite fiber by dissolving the fiber core layer: soaking the prepared skin-core composite fiber with hole grooves and containing sodium sulfate, ammonium sulfate and ammonium chloride in water, and using the fiber hole groove to make the water Immerse into the fiber and soak for 15 hours at a temperature of 50 °C to dissolve sodium sulfate, ammonium sulfate and ammonium chloride in the core layer. After the sodium sulfate, ammonium sulfate and ammonium chloride in the core layer are dissolved, uniform pores can be obtained. Skin-core composite fiber with distributed porous core layer.

The finally obtained skin-core porous composite fiber is a skin-core composite fiber, and holes are distributed in the core layer, the average diameter of the holes is 1500nm, the breaking strength of the skin-core porous composite fiber is 4.0cN/dtex, and the elongation at break is 4.0cN/dtex is 45%.

Claims (10)

1. a preparation method of skin-core type porous composite fiber, it is characterized in that: the skin-core type composite fiber with hole groove and containing soluble inorganic particles is soaked in a solvent to make skin-core type porous composite fiber; The skin-core composite fiber with holes and grooves and containing soluble inorganic particles is obtained by melting the skin-layer raw materials and the core-layer raw materials and spinning them through a skin-core spinneret. The raw material is mainly composed of dissolvable inorganic particles with a decomposition temperature higher than the spinning temperature and a core layer polymer. The part of the spinneret hole of the skin-core spinneret for the skin layer raw material and the core layer raw material to pass through is the skin layer through hole and the core layer respectively. Layer through holes, there are more than one intersecting spokes in the spinneret holes, the spokes are solid long bars, the length direction is perpendicular to the axial direction of the spinneret holes, the spokes are mainly located in the core layer through holes, and one of the spokes is connected to the skin layer through holes. the inner wall of the hole; The solvent is a good solvent for dissolving inorganic particles and a poor solvent for the core polymer and the skin polymer. 2 . The method for preparing a skin-core porous composite fiber according to claim 1 , wherein the cross-sections of the spinneret hole and the core layer through hole are circular, and the diameters are respectively 5-150 μm and 1-100 μm. 3 . . 3 . The method for preparing a skin-core porous composite fiber according to claim 2 , wherein the number of spokes is 3 to 5, the spokes intersect at one point, and the whole is radially distributed, and the length of the spokes is from The dimension of the spoke intersection point radiating to the spoke terminal is 0.5-50 μm, and the width of the spoke, that is, the dimension perpendicular to the length direction of the spoke in the cross-section of the spinneret is 0.1-10 μm. 4. the preparation method of a kind of skin-core porous composite fiber according to claim 3, it is characterized in that, the skin layer through hole and the core layer through hole are tangent, a spoke is connected to the inner wall of the skin layer through hole at the tangent point, the other The spokes are integrally located in the core through-holes. 5. The preparation method of a skin-core porous composite fiber according to claim 1, wherein the core layer raw material is obtained by melt-blending the core layer polymer and the dissolvable inorganic particles; the core layer raw material is obtained by melt blending; The mass ratio of the polymer in the core layer to the soluble inorganic particles is 99:1 to 70:30. 6 . The method for preparing a skin-core porous composite fiber according to claim 1 , wherein, before spinning, each component is vacuum-dried for 10-20 hours at a temperature of 80-180° C. 7 . During spinning, the mass ratio of the raw materials of the skin layer and the raw materials of the core layer is 7:3 to 3:7; Spinning process parameters are: spinning temperature is 200～350℃, spinning temperature fluctuation range is ±1℃, spinning pressure is 6～50MPa, draft ratio is 1～5 times, spinning speed is 1000～6000m/ min. 7 . The method for preparing a skin-core porous composite fiber according to claim 1 , wherein the temperature of the soaking treatment is 25-100° C. and the time is 2-24 hours. 8 . 8. the preparation method of a kind of skin-core type porous composite fiber according to claim 1, is characterized in that, the material of skin layer polymer and core layer polymer is different; One or more of ester, polylactic acid, polyacrylonitrile and polyamide; core layer polymer is one or more of polypropylene, polyester, polyacrylonitrile, polyamide and polyvinylidene fluoride; soluble inorganic particles are One or more of sodium chloride, potassium chloride, ammonium chloride, ammonium sulfate, potassium sulfate and sodium sulfate; the solvent is water. 9. The skin-core porous composite fiber obtained by the method for preparing a skin-core porous composite fiber according to any one of claims 1 to 8 is characterized in that: it is a skin-core composite fiber, and the core layer is Holes are distributed. 10 . The skin-core porous composite fiber according to claim 9 , wherein the average diameter of the pores is 100-5000 nm, the breaking strength of the skin-core porous composite fiber is 2.2-4.0 cN/dtex, and the elongation at break is 2.2 to 4.0 cN/dtex. 11 . 15% to 60%.

Images