CN113981550B

CN113981550B - Method and apparatus for adding liquid/solid additives at specific locations of melt blown fibers

Info

Publication number: CN113981550B
Application number: CN202111283372.6A
Authority: CN
Inventors: 不公告发明人
Original assignee: Shanghai Yingjia Technology Co ltd
Current assignee: Shanghai Yingjia Technology Co ltd
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2022-09-20
Anticipated expiration: 2040-09-01
Also published as: CN111996606B; CN111996606A; CN113981550A

Abstract

The invention discloses a method and equipment for adding a liquid/solid additive at a specific position of a fiber in a melt-blown non-woven process, and relates to the field of chemical fiber manufacturing. The additive is added when the high polymer is extruded from the melt-blowing nozzle and is not or is being drawn into filaments by high-speed airflow or passes through a distribution plate pipeline, so that the additive migrates from the outer surface of the fiber to the surface layer or the tip of the fiber or enters the surface layer or the tip of the fiber through the distribution plate in the process that the high polymer melt is drawn by the high-speed airflow to form the fiber of an outer annular additive structure or a tip additive structure. By adding the additive in a gathering way in a specific area, the influence of the additive on spinning forming and the strength performance of the material is reduced, the cost is reduced, and meanwhile, the effect brought by the additive is obviously improved.

Description

Method and apparatus for adding liquid/solid additives at specific locations of melt blown fibers

The application is a divisional application of Chinese patent application No. 202010906288.4, having an application date of 09/01/2020 and entitled "method and apparatus for adding liquid/solid additives in melt-blown nonwoven process".

Technical Field

The invention relates to the field of chemical fiber manufacturing, in particular to a method and equipment for adding liquid/solid additives at specific positions of melt-blown fibers.

Background

The melt blowing method is a production technique in which a high polymer melt is blown by a high-speed high-temperature air flow to cause a melt stream to be extremely stretched to form ultrafine fibers, then the ultrafine fibers are condensed on a porous roller or a web forming curtain to form a web, and the web is reinforced by self-bonding or thermal bonding to form a nonwoven fabric. The product produced by the melt-blown non-woven fabric has the advantages of high filtering efficiency, low resistance, softness, self-adhesion of fiber webs without adding a binder and the like, and is widely applied to air filtration (medium-efficiency and sub-high-efficiency filtration and the like), personal protection (N95 or KN95 grade dust masks, and spun-bonded fabrics which are compounded into isolation clothes or protective clothes and the like), liquid filtration and battery diaphragms, industrial wiping cloth, heat-insulating materials and the like.

To compensate for the performance deficiencies of the individual polymers, bicomponent or multicomponent spinning techniques have also been applied in the production of melt blown nonwovens to improve the elasticity, softness, cohesion, strength, durability, etc. of the materials. Conventional bicomponent or multicomponent meltblowing equipment and processes are complex and typically have two or more feed systems. A relatively thin metal distribution plate made by using an etching process is described in US 005551588. The use of multiple metal distribution plates as described in the patents in the spinning cell allows the polymer of each component to enter the melt blowing spinneret through corresponding inlet orifices from separate passages; the spinneret described in this patent is relatively inexpensive to manufacture and can be periodically discarded without periodic cleaning. Patent CN100451204C describes a nonwoven fabric made of side-by-side bicomponent meltblown composite fibers with more bulk, softness, air permeability and heat retention, polymer a being PP (30-70%) and polymer B being PET (70% -30%). Patent CN101591837A describes a side-by-side type bicomponent melt-blown material, polymer A is PP (20-80%) modified by tourmaline, polymer B is PET (80-20%), and the bicomponent material is subjected to high-voltage corona discharge electret to prepare the bicomponent melt-blown durable electret non-woven material.

Various liquid and solid additives are widely used in the production of melt blown nonwoven materials. The common additives can be classified into color master batch particles and functional additives (antibacterial agent, toughening agent, electrostatic electret additive, flame retardant and the like) according to functions. However, most functional additives, such as antibacterial agents and electrostatic electret additives, are expensive, and if the functional additives, such as antibacterial agents or electrostatic electret additives, are required to achieve the functions, the amount of the functional additives added in the melt-blown material is large, so that the manufacturing cost of the material is high. Meanwhile, the use of the additive has a great influence on spinning forming, so that the spinning process is more complicated, and the use of part of the additive can reduce the mechanical property of the material, so that the strength, the ageing resistance and the like of the material are influenced. More importantly, part of additives, such as antibacterial agents and oil-resistant additives, can exert the effect only by adhering to the surface of the fiber, and the internal addition does not improve the efficiency of the material but influences the mechanical property, electrostatic stability and other effects of the material; with current spinning processes, additives tend to aggregate inside the fiber.

Chinese patent application 201811248557.1 discloses a method for processing photoaging-resistant polypropylene melt-blown non-woven fabric, which comprises the following steps: the polypropylene melt-blown non-woven fabric fiber adopts a skin-core composite structure, wherein the core layer component is pure polypropylene slices, the skin layer structure is mixed with a light reflecting agent and a light absorbing agent in polypropylene slice master batches for forming the skin layer, and finally, the light aging resistant polypropylene melt-blown non-woven fabric fiber with the skin-core structure and the additives concentrated in the fiber skin layer is prepared. The processing method of the skin-core structure is adopted, so that the additive is distributed on the surface layer of the fiber, and the adverse effect of adding foreign particles on the structure and the performance of the fiber body is reduced. Meanwhile, the use amount of the additive is reduced, the content of the additive on the fiber surface layer is greatly increased, and the absorption and reflection effects of the additive on light on the fiber surface layer are maximized. The formation of this structure requires two sets of feeding systems: one set of molten polypropylene required to provide the core structure to the spinning system and one set of molten polypropylene mixed with a light reflecting and absorbing agent required to provide the sheath structure to the spinning system. The whole process flow is complicated, the occupied area of the machine is large, the improvement on the existing melt-blown spinning equipment is not easy, and the popularization difficulty is high. And the preparation method of the patent can only prepare the fiber material with the sheath-core structure, the control of the two feeding systems is improper, the gap between the sheath and the core is easy to cause, and the loss of the mechanical strength performance is obvious.

In view of the above, the present invention provides a method and an apparatus for adding liquid/solid additives in a melt-blown nonwoven process, which solves the problem of the additive affecting the cost and the mechanical properties of the material, and can be directly realized in the melt-blowing process without being limited by the fiber structure.

Disclosure of Invention

The invention aims to provide a method and equipment for adding liquid/solid additives in a melt-blown non-woven process, which reduce the influence of the additives on spinning forming and the mechanical properties of materials by aggregating and adding the additives in a specific area, reduce the cost and simultaneously obviously improve the effect brought by the additives.

In order to realize the purpose of the invention, the technical scheme of the invention is as follows:

in a first aspect, the present invention provides a method for adding liquid/solid additives to a melt-blown nonwoven process, wherein the additives are added when the high polymer is extruded from a melt-blowing nozzle and is not being or is being drawn into filaments by a high-velocity gas stream or before the high polymer enters a distribution plate, so that the additive high polymer melt migrates from the outer surface of the fiber to the surface layer or tip of the fiber during being drawn by the high-velocity gas stream or enters the surface layer or tip of the fiber through the distribution plate to form fibers with an outer annular additive structure or tip additive structure.

Specifically, the high polymer may be various thermoplastic high polymers, and may be one polymer or a combination of multiple polymers, such as polypropylene (PP), Polyethylene (PE), Polyester (PET), Polycarbonate (PC), polybutylene terephthalate (PBT), Polyamide (PA), Thermoplastic Polyurethane (TPU), Polyphenylene Sulfide (PPs), polylactic acid (PLA), polyamide 6(NL6), Polyamide Ester (PEA), Polychlorotrifluoroethylene (PCTFE), and the like.

Specifically, the additive may be various liquid additives and solid additives, and may be one additive or a combination of additives such as an antibacterial agent, an electrostatic electret additive, an antioxidant, a flame retardant, an oil-repellent additive, a toughening agent, a surfactant, a dye, and the like; preferably an antibacterial agent or an electrostatic electret additive.

Preferably, the mass fraction of the additive in the fiber is 0.05-3%.

The antibacterial agent includes, but is not limited to, inorganic antibacterial agents, organic antibacterial agents, natural antibacterial agents; inorganic antibacterial agents such as metal ions such as silver, copper, and zinc, metal compounds such as zinc oxide, copper oxide, ammonium dihydrogen phosphate, and lithium carbonate, and porous materials on which metal ions are supported; organic antibacterial agents such as acylanilines, imidazoles, thiazoles, isothiazolone derivatives, quaternary ammonium salts, biguanides, phenols and the like; the natural antibacterial agent is selected from chitin, mustard, oleum ricini, horseradish, chitosan, insect antibacterial protein, Chinese juniper, folium Artemisiae Argyi, Aloe, Glycyrrhrizae radix, herba Houttuyniae, folium Camelliae sinensis, pericarpium Granati, Chalcanthitum, Realgar, etc.

The electrostatic electret additives include, but are not limited to, high dielectric constant inorganic additives, auxiliary nucleating agents, antioxidants, anti-oil additives, and the like; the high dielectric constant inorganic additive such as alumina, magnesia, barium oxide, etc.; such as carbon black, kaolin, titanium dioxide, carboxylates, magnesium stearate, and the like.

Examples of the antioxidant include hindered phenol type antioxidants, hydroxylamine type antioxidants, bisphenol type antioxidants, ultraviolet absorbing type antioxidants and the like.

Such as fluorine-containing oil repellent additives and the like.

The flame retardant includes, but is not limited to, halogen-based flame retardants, phosphorus-based flame retardants, aluminum hydroxide, magnesium hydroxide, and the like.

Specifically, the outer ring-shaped additive structure refers to that the additive is gathered on the outer ring of the fiber with a circular or oval cross section, as shown in the attached figure 1.

Specifically, the tip additive structure means that the additive is concentrated at the convex end of the fiber having a convex end in cross section, preferably the convex end of the profile section, as shown in fig. 2.

Specifically, the addition method includes a direct method and a distribution plate method.

The direct method comprises the following specific steps:

(1) adopting a single-component melt-blowing system to melt the slices of the high polymer at high temperature in a feeding bin, and extruding the high polymer melt through an extruding device and a metering device;

(2) the high polymer melt sequentially passes through a die head device, a distribution plate and a melt-blown nozzle to extrude melt trickle, and additives are discharged from an additive box body through a single pipeline and are attached to the melt trickle;

(3) by air drawing, the melt trickle attached with the additive forms micron-sized or submicron-sized fiber bundles, and the fiber bundles are gathered on a web forming roller or a web forming curtain to form the melt-blown non-woven fabric.

Preferably, in the step (2), the additive box body is provided with an atomizing device, and the additive is atomized and attached to the melt trickle from an outlet pipe of the additive box body.

In the method, the additive is added when the high polymer is extruded from the melt-blowing nozzle and is not or is being drawn into filaments by the high-speed airflow, so that the additive migrates from the outer surface of the fiber to the surface layer or the tip of the fiber during the process that the high polymer melt is drawn by the high-speed airflow, and the fiber with an outer annular additive structure or a tip additive structure is formed, and the migration process of the additive is shown in figures 3-6.

The distribution plate method comprises the following specific steps:

(1) the liquid supply system of a single-component melt-blowing machine is combined with the spinning system of a double-component or multi-component melt-blowing machine, the slices of the high polymer are melted at high temperature in a feeding bin, and the high polymer melt is extruded by an extruding device and a metering device;

(2) the high polymer melt sequentially passes through a die head device and a distribution plate of a bi-component or multi-component system, additives enter a distribution plate pipeline from an additive box body through a single pipeline, are converged with the high polymer and enter a specified position of a bi-component or multi-component spinning head, and melt trickle is extruded from a melt-blown nozzle; the designated position corresponding to the additive is an outer ring or a protruding tip of the fiber;

(3) and forming the melt fine flow into micron-sized or submicron-sized fiber bundles through air drawing, and gathering the fiber bundles on a web forming roller or a web forming curtain to form the melt-blown non-woven fabric.

Preferably, in the step (2), the distribution plate comprises a distribution plate of a two-component or multi-component system and a needle of the two-component or multi-component system.

Preferably, in the step (2), when the additive is a solid additive, the state is a nano powder.

Preferably, in the step (2), the additive is atomized or melted and then enters the distribution plate pipeline.

Preferably, in step (2), the outer ring is: an outer ring of fibers having a circular or elliptical cross-section as shown in figure 1. Further preferred is a core-shell structure fiber, wherein the cross-sectional area ratio of the core-shell component is 1-9: 1.

Preferably, the convex tip in step (2) refers to: the protruding ends of the fibers having a protruding end in cross-section are further preferably protruding ends of a lobed cross-section, as shown in fig. 2.

In this process, the high polymer passes through the distribution plate conduits and enters the conduits of the core and shell portions, respectively, which may be bi-or multi-component. In the conduits of the shell portion, additives are added such that the additives pass through the distribution plate into the fiber skin or tip, forming fibers of an outer annular additive structure or a tip additive structure.

The invention further provides equipment used in the direct method, wherein the equipment is a single-component melt-blowing system, an outlet pipe of an additive box body is arranged at the outlet of a melt-blowing nozzle, and the additive box body is preferably provided with an atomizing device.

Furthermore, the invention provides an apparatus for use in the above-described dispensing plate method, which apparatus combines a liquid supply system of a single-component melt-blowing machine with a spinning system of a two-component or multi-component melt-blowing machine, and which employs a two-component or multi-component dispensing plate, and in which an outlet pipe of an additive cartridge, preferably equipped with an atomizing device, is connected to a line of the dispensing plate.

Finally, the invention provides a fiber prepared according to the above-described preparation method or using the above-described apparatus.

Compared with the prior art, the invention has the following beneficial effects:

(1) the additive is only aggregated in a specific area, so that the influence of the additive on the spinning forming and material strength performance is reduced, and the aggregation of the additive in the center of the cross section of the fiber is avoided;

(2) the additive is utilized to the maximum extent, the waste of the additive in an invalid area is avoided, the additive effect is improved, the using amount of the additive is reduced, and the process cost is reduced;

(3) the method can add independent additive box bodies and pipelines in the traditional single-component melt-blowing system, can also adopt a mode of combining a liquid supply system of a single-component melt-blowing machine and a spinning system of a double-component melt-blowing machine, is not limited by equipment, and is easy to implement.

Drawings

FIG. 1 is a schematic diagram of the structure of the outer ring-shaped additive of the present invention;

FIG. 2 is a schematic view of a tip additive structure of the present invention;

FIG. 3 is a schematic illustration of solid additive migration for the outer ring structure of the present invention;

FIG. 4 is a schematic diagram of the migration of liquid additives in the outer ring structure of the present invention;

FIG. 5 is a schematic illustration of the tip structure solid state additive migration of the present invention;

FIG. 6 is a schematic view of the tip structure liquid additive migration of the present invention;

FIG. 7 is a schematic diagram of the direct process apparatus of the present invention;

FIG. 8 is a schematic view of an apparatus for use in the distribution plate process of the present invention.

Detailed Description

The present invention will be further explained with reference to specific embodiments in order to make the technical means, the original characteristics, the achieved objects and the effects of the present invention easy to understand, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments are possible. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative efforts belong to the protection scope of the present invention.

The experimental methods in the following examples are conventional methods unless otherwise specified, and materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

With the apparatus shown in FIG. 7, which is a single component meltblowing system, an outlet pipe 516 for an additive cartridge 515, which is equipped with a high-pressure atomizing device, is provided at the meltblowing nozzle 007.

The direct method is adopted to prepare the melt-blown non-woven fabric, as shown in figure 7:

(1) carrying out high-temperature melting on polypropylene high-molecular polymer slices with melt index MFI of 1500-1600 g/10 min (the melting point is 173 ℃) in a feeding bin 001 at the temperature of 275 +/-10 ℃, and extruding a polypropylene melt through a screw extruder 002 and a gear metering pump 004;

(2) the high polymer melt sequentially passes through a clothes hanger type die head device 005, a distribution plate 006 and a melt-blowing nozzle 007, when the high polymer is extruded from the melt-blowing nozzle with the diameter of 250 micrometers, nano silver particles (the particle size ranges from 1 nm to 20nm)014 in a powder structure are discharged from an additive box body 515 of an atomization device with high-pressure gas assistance and are attached to a polypropylene melt trickle 011 through a single pipeline 516;

(3) the high-speed airflow 013 is heated to 180 +/-20 ℃ through the air heater 003 and enters the spinning unit 008 through the airflow channel and the air plate 012, the airflow draws and stretches the polypropylene melt stream 517 attached with the nano-silver particle additive 014 to form fibers 518 with the average diameter of 2-4 microns, and the fibers 518 are gathered on the net curtain 010 to form the meltblown nonwoven fabric with annular round fibers.

The nano particles can be added through a direct gas atomization device similar to a fluidized bed or an indirect atomization device which disperses the nano particles in water or other solvents and then atomizes and dries the solution, and the mass percent of the additive in the fiber 518 is controlled to be 0.05 percent by adjusting the adding speed of the atomization device.

Example 2

The apparatus shown in fig. 8, which is a combination of a liquid supply system of a single-component melt-blowing machine and a spinning system of a double-component melt-blowing machine, employs a core-shell double-component distribution plate 006, and an outlet pipe 716 of an additive cartridge 715 is connected to a pipeline of the distribution plate.

A melt-blown nonwoven was prepared using a distributor plate process, as shown in fig. 8:

(1) the high-temperature melt method comprises the following steps of (1) carrying out high-temperature melting on polypropylene high-molecular polymer slices with melt index MFI of 1500-1600 g/10 min (the melting point is 173 ℃), and extruding a polypropylene melt through a screw extruder 002 and a gear metering pump 004 in a feeding bin 001 at the temperature of 275 +/-10 ℃;

(2) the spinning unit 008 adopts a core-shell bi-component distribution plate design and a needle head design, the polypropylene melt passes through the coat hanger type die head device 005 and the distribution plate 006 in sequence, enters a designated position through the needle head after the distribution plate pipeline is converged with the additive, and enters the melt-blown nozzle 007; the diameter of the opening of the core-shell bi-component needle is 300 microns, the diameter of the core part of the needle is 210 microns, and the cross-sectional area ratio of the core-shell components is 1: 1. The molten polypropylene polymer flows into the inner core part of the bi-component needle head through the distribution plate 006, the additive magnesium stearate 014 is melted at high temperature and then enters a distribution plate pipeline from the additive box 715 through the single pipeline 716, and is converged with the molten polypropylene high polymer 011 to enter the shell of the bi-component spinning head with the core-shell structure, and a mixed melt trickle 717 is extruded from the melt-blowing nozzle 007;

(3) the high-speed airflow 013 is heated to 200 +/-20 ℃ by an air heater 003 and enters the spinning unit 008 through an airflow channel and an air plate 012; the air stream pulls and stretches the polypropylene melt stream 717 with the magnesium stearate 014 attached, forming fibers 718 with an average diameter of 3-6 microns, and the fibers 718 coalesce into the web 010 forming a meltblown nonwoven with round fibers having an additive ring structure.

By adjusting the addition rate, the mass percent of the additive in the fiber 718 is controlled to be 1%.

Example 3

With the apparatus shown in FIG. 7, which is a monocomponent meltblowing system, an outlet pipe 516 of an additive cartridge 515, which is equipped with a high-pressure atomizing device, is provided at the meltblowing nozzle 007.

(2) the high polymer melt sequentially passes through a clothes hanger type die head device 005, a distribution plate 006 and a melt-blowing nozzle 007, when the high polymer is extruded from a trilobal melt-blowing nozzle (the peripheral diameter formed by the three-blade tip of the nozzle is 300 microns, and the diameter formed by the bottom end of the three blades is about 150 microns), nano silver particles (the particle size ranges from 1 nm to 20nm)014 in a powder structure are discharged from an additive box body 515 of an atomizing device provided with high-pressure gas assistance and are attached to a polypropylene melt trickle 011 through a single pipeline 516;

(3) the high-speed airflow 013 is heated to 180 +/-20 ℃ through the air heater 003, enters the spinning unit 008 through the airflow channel and the air plate 012, and draws and stretches the polypropylene melt trickle 517 attached with the nano silver particle additive 014, and most of nano silver particles migrate to the tail end of the fiber in the drawing process to form a trilobal fiber 518 with the peripheral diameter of 1-4 microns, wherein the tail end of the fiber is provided with an additive gathering band. The fibers 518 are gathered into a web 010 to form a meltblown nonwoven having polymeric trilobal fibers with end additives.

The nano particles can be added through a direct gas atomization device similar to a fluidized bed or an indirect atomization device which disperses the nano particles in water or other solvents and then atomizes and dries the solution, and the mass percent of the additive in the fiber 518 is controlled to be 0.15 percent by adjusting the adding speed of the atomization device.

Example 4

(1) the high-temperature melt method comprises the following steps of (1) carrying out high-temperature melting on a polypropylene high polymer slice with the melt index MFI of 1500-1600 g/10 min (the melting point is 173 ℃), and extruding a polypropylene melt through a screw extruder 002 and a gear metering pump 004 in a feeding bin 001 at the temperature of 275 +/-10 ℃;

(2) the spinning unit 008 adopts a trilobal component distribution plate design and a needle head design, the polypropylene melt passes through the hanger-type die head device 005 and the distribution plate 006 in sequence, and enters a specified position through the needle head after the distribution plate pipeline is converged with the additive, and then enters the melt-blowing nozzle 007; the tip of the nozzle tri-lobe forms a perimeter diameter of 300 microns and the base of the tri-lobe forms a diameter of about 150 microns. The molten polypropylene polymer flows into the central part of the trilobal component through the distribution plate 006, the magnesium stearate serving as the electrostatic electret additive enters a distribution plate pipeline from the additive box body 715 through a separate pipeline 716 and is merged with the molten polypropylene high polymer 011 into a convex part of the trilobal component, and a mixed melt trickle 717 is extruded from the melt-blowing nozzle 007;

(3) the high-speed airflow 013 is heated to 200 +/-20 ℃ by an air heater 003 and enters the spinning unit 008 through an airflow channel and an air plate 012; the air stream pulls and stretches the polypropylene melt stream 717 with the attached electrostatic electret additive 014 to form fibers 718 having an average diameter of 3-6 microns, and the fibers 718 coalesce into the web 010 to form a meltblown nonwoven with additive tipped coalesced trilobal fibers.

By adjusting the addition rate, the mass percent of the additive in the fiber 718 is controlled to be 0.5%.

Comparative example 1

An apparatus as shown in fig. 7, but without the additive cartridges and conduits, was used, which was a single component melt blowing system.

The direct method is adopted to prepare the melt-blown non-woven fabric, as shown in figure 7: (1) mixing the slices of polypropylene high molecular polymer with melt index MFI of 1500-1600 g/10 min (melting point of 173 ℃) and nano silver particles (particle size range is 1-20nm) in a powder structure according to a ratio of 99.95: 0.05, mixing in a feeding bin 001, melting at 275 +/-10 ℃, and extruding a polypropylene melt through a screw extruder 002 and a gear metering pump 004;

(3) the high-speed airflow 013 is heated to 180 +/-20 ℃ through the air heater 003 and enters the spinning unit 008 through the airflow channel and the air plate 012, the airflow draws and stretches the polypropylene melt trickle 517 attached with the nano-silver particle additive 014 to form fibers 518 with the average diameter of 2-4 microns, and the fibers 518 are gathered on the mesh screen 010 to form the melt-blown nonwoven fabric of round fibers.

Comparative example 2

(1) mixing the polypropylene high molecular polymer slices with the melt index MFI of 1500-1600 g/10 min (the melting point is 173 ℃) and magnesium stearate according to the proportion of 99: 1 in the feeding bin 001, melting at 275 +/-10 ℃, and extruding a polypropylene melt through a screw extruder 002 and a gear metering pump 004;

(3) the high-speed air current 013 is heated to 180 +/-20 ℃ through the air heater 003 and enters the spinning unit 008 through the air current channel and the air plate 012, the air current draws and stretches the polypropylene melt trickle 517 attached with the magnesium stearate additive 014 to form fibers 518 with the average diameter of 2-4 microns, and the fibers 518 are gathered on the mesh screen 010 to form the melt-blown nonwoven fabric with round fibers.

Comparative example 3

Unlike example 2, a meltblown nonwoven fabric was prepared according to the method described in chinese patent application 201811248557.1, and the cross-sectional area ratio of the core/shell component, the type of additive and the amount of additive were the same as in example 2.

Comparative example 4

Unlike example 1, a conventional meltblown nonwoven fabric was prepared without any additives.

And (4) checking the result:

1. tensile Strength test

The test method comprises the following steps: the process described in the examples and comparative examples, respectively, was followed to produce a grammage of 75g/m ² The melt-blown nonwoven fabric is heated by a hot rollerAnd (6) performing qualitative treatment, and testing the strength of the fiber. The test results and methods are shown in table 1:

table 1.

The results in Table 1 show that the nonwoven fabrics prepared in examples 1 to 4 have less loss of tensile strength in both the transverse and longitudinal directions than the nonwoven fabric of comparative example 4 to which no additive is added; comparative examples 1-2 the nonwoven fabric prepared using the conventional addition method had a relatively large loss of tensile strength, and comparative example 3 had a large loss of longitudinal tensile properties due to the nonwoven fabric of the core-sheath structure.

2. Electret effect test

The test method comprises the following steps: the obtained melt-blown nonwoven fabric was subjected to electrostatic electret treatment (charging voltage 50kV, electrode filament distance 8cm from the plate) using a corona discharge method. According to the GB2626 reference method, TSI 8130A is used as a test instrument, sodium chloride aerosol with the mass median diameter of 0.26 micron is used as a measuring medium, and the filtration efficiency of a test material at the flow rate of 85L/min is tested. The test results are shown in table 2:

table 2.

Group of	Gram weight (g/m) ² )	Filtration efficiency (%)	Air pressure drop (Pa)
				Example 2	24.6	98.5	42
Example 4	26.1	97.6	38
				Comparative example 2	27.2	92.4	43
Comparative example 3	26.8	95.2	42

As can be seen from Table 2, the nonwoven fabric of fibers with aggregated outer rings and aggregated ends prepared by the method has greatly improved filtration efficiency, compared with the common addition method, the filtration efficiency is improved from 92.4 percent to 98.5 percent, and the nonwoven fabric is superior to the nonwoven fabric with a sheath-core structure, the dosage of additives can be reduced, and the cost is saved.

3. Test of antibacterial Effect

The test method comprises the following steps: the second part was evaluated using the antibacterial properties of GB/T20944.2-2007 textiles: the absorption method is used for testing, and the test results are shown in table 3:

table 3.

	Staphylococcus aureus	Escherichia coli
			Group of	Bacteriostatic ratio (%)	Bacteriostatic ratio (%)
Example 1	>99	>99
			Example 3	>99	>99
Comparative example 1	90-95	90-95

As can be seen from Table 3, the nonwoven fabric of the fibers with the aggregated outer rings and the aggregated tail ends, prepared by the invention, has a greatly improved bacteriostatic rate compared with the common nonwoven fabric, and has bacteriostatic rates on staphylococcus aureus and escherichia coli of more than 99%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method for adding liquid or solid additives in a melt-blown non-woven process is characterized in that the additives are added when high polymers are extruded from a melt-blown spray head through a distribution plate pipeline, so that the additives enter the surface layer or the tail end of fibers through the distribution plate to form fibers of an outer annular additive structure or a tail end additive structure;

the method comprises the following specific steps:

2. The addition method according to claim 1, wherein the mass fraction of the additive in the fiber is 0.05 to 3%.

3. The addition method according to claim 1, wherein the outer annular additive structure means that the additive is gathered in an outer ring of fibers having a circular or elliptical cross section.

4. The addition method as described in claim 1, wherein the tip additive structure means that the additive is concentrated at the convex end of the fiber having the convex end in the cross section.

5. The apparatus used in the method of claim 1, wherein the apparatus is a combination of a liquid supply system of a single-component melt blowing machine and a spinning system of a two-component or multi-component melt blowing machine, and a two-component or multi-component distribution plate is used, and an outlet pipe of the additive cartridge is connected to a pipeline of the distribution plate.