CN111703042A

CN111703042A - Preparation method of carrier-free plastic filling master batch and product thereof

Info

Publication number: CN111703042A
Application number: CN202010614175.7A
Authority: CN
Inventors: 代少俊
Original assignee: Yancheng Institute of Technology
Current assignee: Suzhou Runbu New Material Co ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2020-09-25
Anticipated expiration: 2040-06-30
Also published as: CN111703042B

Abstract

The invention discloses a preparation method of carrier-free plastic filling master batch, which comprises the steps of adding attapulgite into deionized water, heating to 60-90 ℃, adding metaphosphoric acid, stirring, and performing ultrasonic treatment for 1-3 hours to obtain attapulgite dispersion liquid; adding an inorganic filler into the attapulgite dispersion liquid, mixing at 150-250 rpm for 1min, and then mixing at 800-2000 rpm for 5min to obtain a mixed material; and (3) putting the mixed material into an extruder for normal temperature extrusion, wherein the extrusion pressure is 2-5 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 2-4, and the extruded particles are dried at the temperature of 105-170 ℃ for 0.5-1.5 h to obtain the carrier-free plastic filling master batch. The attapulgite is used as the binder, and the prepared master batch has low hardness and is easy to disperse in plastics; the attapulgite can be used as a natural needle-shaped nano material and can also be used as a reinforcing filler to reinforce and toughen the plastic composite.

Description

Preparation method of carrier-free plastic filling master batch and product thereof

Technical Field

The invention belongs to the technical field of plastic processing, and particularly relates to a preparation method of carrier-free plastic filling master batch and a product thereof.

Background

The plastic filling master batch is applied to plastics, can reduce the raw material cost of plastic products, saves synthetic plastics, brings economic benefits for enterprises, and is favored by the plastic processing industry. The conventional plastic filling calcium master batch is prepared from plastic, a coupling agent, a lubricant, an inorganic filler and the like. At present, equipment such as a double-screw extruder or an internal mixer is usually adopted for producing the filling master batch, and the carrier-filled master batch is prepared by high-temperature melting plasticization and mixing, cooling and granulation, wherein the defects of the method are as follows: 1) the prepared filling master batch needs to be added with a certain amount of plastic as a carrier, the content of the inorganic filler is difficult to exceed 80%, and in order to enable the plastic and the inorganic filler to be uniformly dispersed and form particles, preheating, melting, plasticizing and mixing processes are needed, and then cooling granulation is carried out, so that energy is greatly wasted, the manufacturing cost of the product is increased, and the filling master batch is not suitable for future low-carbon and economic social requirements; 2) the preparation equipment and the process method of the master batch are only suitable for the filling master batch which uses plastic as a matrix carrier, so that the prepared filling master batch is only suitable for being added into a filling product compatible with a master batch matrix, and the universality of the filling master batch is poor. For example, conventional plastic masterbatch uses non-polar polyolefin as a carrier, has poor dispersibility in polar polymers such as polyester and nylon, and is easily decomposed at the processing temperature of polyester and nylon. Patent CN 106832399B adopts polypropylene alcohol as a dispersing agent and an adhesion agent to prepare a graphene composite polypropylene alcohol master batch, the content of inorganic filler in the master batch can reach more than 90%, although the master batch does not adopt conventional polyolefin as a carrier, the used polypropylene alcohol is also one of high molecules, the master batch is only suitable for polar high molecules such as polyester or nylon, and the universality is poor; and the content of the inorganic filler in the master batch still does not reach 100 percent.

The carrier-free master batch is a hotspot of the research of the prior plastic filling master batch, the carrier-free master batch refers to that no plastic is used, but an adhesive is used for bonding inorganic filler into granules, and the master batch has good universality because no plastic is used as a carrier. Patent CN102504334B discloses a method for preparing a talcum powder filling master batch with high content and wide universality by taking 3-5% (weight ratio) of water as a diluent and 1-3% (weight ratio) of sodium silicate as an adhesive and stirring at normal temperature and carrying out double-rod pressure granulation, but the chemical action exists between the adhesive and a filler, so that the obtained master batch has high hardness, and poor dispersibility in plastics is caused; the master batch also contains components which do not act on plastics, such as sodium silicate and the like, namely the filler content of the master batch is less than 100 percent.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.

Therefore, the invention aims to overcome the defects in the prior art and provide a preparation method and a product of plastic filling master batch with the inorganic filler content of 100 percent, proper hardness, good dispersibility and wide universality.

In order to solve the technical problems, the invention provides the following technical scheme: a preparation method of carrier-free plastic filling master batches comprises the steps of adding attapulgite into deionized water, heating to 60-90 ℃, adding metaphosphoric acid, stirring, and carrying out heating ultrasonic treatment for 1-3 hours to obtain an attapulgite dispersion liquid; adding an inorganic filler into the dispersion liquid attapulgite dispersion liquid, mixing at 150-250 rpm for 1min, and then mixing at 800-2000 rpm for 5min to obtain a mixed material; and (3) putting the mixed material into an extruder for normal temperature extrusion, wherein the extrusion pressure is 2-5 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 2-4, and the extruded particles are dried at the temperature of 105-170 ℃ for 0.5-1.5 h to obtain the carrier-free plastic filling master batch.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: and adding metaphosphoric acid and stirring, wherein the stirring speed is 800-2000 rpm, and the stirring time is 5-10 min.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: and carrying out ultrasonic treatment for 1-3 h, wherein the ultrasonic power is 1200-2000W, and the temperature is 60-90 ℃.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: the attapulgite has the characteristics that the wet sieve residue of a 200-mesh sieve is less than or equal to 2.5 percent, the dry sieve residue of a 100-mesh sieve is less than or equal to 2.0 percent, and the water content is less than or equal to 15 percent.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: and obtaining the attapulgite dispersion liquid, wherein the mass ratio of the attapulgite to the deionized water to the metaphosphoric acid in the attapulgite dispersion liquid is 40: 60-160: 0.5 to 1.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: the inorganic filler comprises one or more of calcium carbonate, titanium dioxide, wollastonite, magnesium hydroxide or aluminum hydroxide.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: the inorganic filler is characterized in that the shape is spherical, and the grain diameter is not less than 800 meshes.

As a preferred scheme of the preparation method of the carrier-free plastic filling master batch, the preparation method comprises the following steps: adding an inorganic filler into the attapulgite dispersion liquid, wherein the mass ratio of the inorganic filler to the attapulgite dispersion liquid is 100: 5 to 25.

The invention has the beneficial effects that:

(1) the invention adopts the attapulgite as the binder, does not add any macromolecular component, has the content of the inorganic filler reaching 100 percent, has good universality and low cost compared with the plastic carrier master batch, can be used for nonpolar plastics and polar macromolecules, and does not have the problem of pyrolysis.

(2) Compared with the master batch prepared by using sodium silicate as a binder, the attapulgite used in the invention has small binding power, low master batch hardness and good dispersibility in plastics, because the principle of binding the inorganic filler by the sodium silicate has chemical binding action besides dehydration binding action, the principle is as follows: na (Na)₂SiO+CO₂+HO＝H₂SiO₃+Na₂CO₃The silicic acid is dehydrated and newly precipitated under the action of water on the surface of the inorganic fillerColloidal SiO₂Binding the particles together; because the inorganic fillers are bonded together through chemical bonds, the obtained master batch has high hardness and is not easy to disperse in a plastic matrix, and the attapulgite prepared by the invention is used as a binder and has only dehydration and bonding effects and no chemical bonding effect.

(3) The carrier-free plastic filling master batch obtained in the invention has excellent performance and composite reinforcing and toughening effects on plastics, because the attapulgite is adopted in the invention, the attapulgite is a needle-shaped material with the diameter of 20-70 nm and the length of about 1 micron, the bonded inorganic filler is spherical particles, when the master batch is added into the plastics, when the plastics are subjected to external force, the rigid spherical particles cause the matrix plastics to be silvered and absorb energy, and thus the toughening effect is achieved; the needle-shaped particles are easy to be directionally arranged according to a certain direction in the processing process, so that the strength of the plastic in the directional direction is improved, and other master batches only have one filler and only have a single reinforcing or toughening effect.

(4) The master batch obtained in the invention only uses two materials: the attapulgite clay is not only a binder but also a reinforcing agent, namely all components in the master batch have effects on plastics, the content of the filler reaches 100 percent, and the equipment and the process used in the master batch preparation process are simple, the method is mature, the implementation is convenient, and the popularization is easy.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The attapulgite and the commercially available colloidal attapulgite in the invention have the wet sieve residue of 200 meshes of less than or equal to 2.5 percent, the dry sieve residue of 100 meshes of less than or equal to 2.0 percent and the water content of less than or equal to 15 percent; other raw materials, which are not specifically described, are all commercially available.

Example 1

(1) Adding 40 parts by mass of attapulgite into 60 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

(2)100 parts by mass of 2000 mesh calcium carbonate was added with 15 parts by mass of the attapulgite dispersion, and the mixture was mixed at a low speed of 200rpm for 1min and then at a high speed of 900rpm for 5 min.

(3) And (3) putting the calcium carbonate subjected to stirring and mixing treatment into an extruder for normal-temperature extrusion, wherein the extrusion pressure is 2 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 2-3, and the extruded particles are dried for 1 hour at 150 ℃ to obtain the calcium carbonate master batch product.

Example 2

(1) Adding 40 parts by mass of attapulgite into 90 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

(2)100 parts by mass of 2000 mesh calcium carbonate was added to 15 parts by mass of the attapulgite dispersion, and the mixture was mixed at a low speed of 200rpm for 1min and then at a high speed of 900rpm for 5 min.

(3) And (3) putting the inorganic filler subjected to stirring and mixing treatment into an extruder for normal-temperature extrusion, wherein the extrusion pressure is 2 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 2-3, and the extruded particles are dried for 1 hour at 150 ℃ to obtain the calcium carbonate master batch product.

Example 3

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

(3) And (3) putting the inorganic filler subjected to stirring and mixing treatment into an extruder for normal-temperature extrusion, wherein the extrusion pressure is 2 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 3-4, and the extruded particles are dried for 1 hour at 150 ℃ to obtain the calcium carbonate master batch product.

Example 4

(1) Adding 40 parts by mass of attapulgite into 150 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

Example 5

(2) To 100 parts by mass of 2000 mesh calcium carbonate, 25 parts by mass of the attapulgite dispersion was added, and the mixture was mixed at a low speed of 200rpm for 1min and then at a high speed of 900rpm for 5 min.

0, 2, 4, 6, 8 and 10 parts of the master batch prepared in example 5 were added to 100 parts of polypropylene, respectively, and subjected to extrusion granulation by twin screw: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The surface of the sample was smooth, and the tensile strength and impact strength were measured, and the results are shown in Table 1.

TABLE 1

As can be seen from Table 1, when the amount of the master batch was 4 parts per 100 parts of polypropylene, the tensile strength and impact strength of the resulting specimens were optimized and higher than those without the master batch. The master batch obtained by the invention has excellent performance, and can exert the effect of increasing the tensile strength of the attapulgite and the effect of increasing the impact strength of the calcium carbonate under the condition of proper addition proportion, namely the attapulgite and the calcium carbonate have synergistic effect of enhancing and toughening.

Example 6

(2)100 parts by mass of 2000 mesh calcium carbonate was added with 5 parts by mass of the attapulgite dispersion, and the mixture was mixed at a low speed of 200rpm for 1min and then at a high speed of 100rpm for 5 min.

(3) And (3) putting the inorganic filler subjected to stirring and mixing treatment into an extruder for normal-temperature extrusion, wherein the extrusion pressure is 4 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 3-4, and the extruded particles are dried at 150 ℃ for 1.5 hours to obtain the calcium carbonate master batch product.

Adding 4 parts of the master batch product prepared in the embodiment 1-6 into 100 parts of polypropylene respectively, and performing twin-screw extrusion granulation: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The tensile strength and impact strength were measured and the results are shown in Table 2.

TABLE 2

As is apparent from Table 2, when 15 parts of the attapulgite dispersion was added to 100 parts of calcium carbonate (example 2-4), the impact strength of polypropylene increased and the tensile strength decreased as the concentration of attapulgite in the attapulgite dispersion decreased. The proportion of the attapulgite added into the master batch is reduced and the proportion of the calcium carbonate is increased due to the reduction of the concentration of the attapulgite; the attapulgite is needle-shaped particles, and is easy to be directionally arranged according to a certain direction in the processing process, so that the tensile strength of the polypropylene plastic is improved. In examples 4 to 6, the attapulgite dispersion liquid was uniform in concentration, but the addition amounts were different, and the final master batch was different in the addition amount of attapulgite, and example 5 had the highest proportion of attapulgite and the highest tensile strength of polypropylene; the attapulgite of example 6 had the lowest proportion and the lowest tensile strength. In example 1, the highest concentration of the attapulgite dispersion did not give the best dispersibility, and therefore the tensile strength and impact strength were also reduced compared to example 2.

Example 7

(1) Adding 0, 2, 4, 6, 8 and 10 parts of commercially available polypropylene carrier calcium carbonate master batch (purchased from Nantong Ruihai plastics science and technology Co., Ltd., white master batch RC-633) into 100 parts of polypropylene, and performing extrusion granulation by adopting a double screw: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The tensile strength and impact strength were measured and the results are shown in Table 3.

TABLE 3

(2) Adding 0, 2, 4, 6, 8 and 10 parts of sodium silicate bonded calcium carbonate master batch (master batch prepared by the scheme in CN 102504334B) into 100 parts of polypropylene, and performing twin-screw extrusion granulation: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The tensile strength and impact strength were measured and the results are shown in Table 4.

TABLE 4

As can be seen from Table 4, the use of the polypropylene carrier masterbatch improves the impact strength to a certain extent, but reduces the tensile strength; table 4 shows that the tensile strength and impact strength are reduced when the calcium carbonate master batch is bonded with sodium silicate. And the surface of the product is not smooth, which indicates that the filler is not well dispersed in the product.

Example 8

On the basis of example 5, the influence of the mass ratio of calcium carbonate to the attapulgite dispersion on the properties of the prepared master batch product was investigated, and the other conditions were the same as those in example 5. The experimental design is as follows:

test 1: 100 parts by mass of calcium carbonate and 5 parts by mass of attapulgite dispersion liquid;

test 2: 100 parts by mass of calcium carbonate and 10 parts by mass of attapulgite dispersion liquid;

test 3: 100 parts by mass of calcium carbonate and 20 parts by mass of attapulgite dispersion liquid;

test 4: 100 parts by mass of calcium carbonate and 30 parts by mass of attapulgite dispersion.

Adding 4 parts of the master batch products obtained in the tests 1-4 into 100 parts of polypropylene respectively, and performing extrusion granulation by adopting a double screw: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The tensile strength and impact strength were measured and the results are shown in Table 5.

TABLE 5

As can be seen from Table 5, when the attapulgite dispersion liquid is 5 to 20 parts by mass, the polypropylene tensile strength is increased due to the increase of the proportion of the needle-like attapulgite which plays a reinforcing role in the master batch; the impact strength decreases. However, when the content of the attapulgite dispersion reaches 30 parts by mass, the dispersibility of the resulting master batch in polypropylene begins to decrease due to a high proportion of attapulgite and a high cohesive force, and the tensile strength and the impact strength both decrease.

Example 9

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of sodium pyrophosphate, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

Example 10

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 1 part by mass of sodium pyrophosphate, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

Adding 4 parts of the master batch prepared in examples 9 and 10 to 100 parts of polypropylene respectively, and performing twin-screw extrusion granulation: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The surface of the sample was smooth, and the tensile strength and impact strength were measured, and the results are shown in Table 6.

TABLE 6

	Example 5	Example 9	Example 10
				Tensile Strength (MPa)	31.7	29.2	29.8
Impact Strength (kJ/m)²)	15.7	14.4	14.9

It can be seen from table 6 that, when the attapulgite treating agent is replaced by sodium pyrophosphate, the performance of the prepared calcium carbonate master batch is reduced, the prepared attapulgite has different bonding properties possibly due to the combination of different treating agents and ultrasonic action, meanwhile, the attapulgite has a unique microstructure after being specifically treated by the invention, the diameter of the attapulgite is 20-70 nm, the length of the attapulgite is 0.8-1 micron needle-shaped, and the attapulgite is easy to be directionally arranged according to a certain direction in the plastic processing process, so that the strength of plastic in the directional direction is improved, and simultaneously, the attapulgite with the unique microstructure is combined with spherical particles of inorganic filler possibly due to the fact that crystal bundles in the attapulgite are randomly staggered in the space structure, the microstructure among the crystal bundles is loose, and the attapulgite with the unique microstructure is combined with the spherical particles of the inorganic filler, so that the effect of synergistically increasing the strength of the plastic is achieved. When other treating agents are adopted, the performance of the prepared calcium carbonate master batch is reduced.

Example 11

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 5min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 0.5 h to obtain the attapulgite dispersion.

Example 12

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 0.5 h to obtain the attapulgite dispersion.

Example 13

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 2000W and 90 ℃ for 2 hours to obtain the attapulgite dispersion.

Example 14

(1) Adding 40 parts by mass of attapulgite into 120 parts by mass of deionized water, heating to 80 ℃, adding 0.6 part by mass of metaphosphoric acid, stirring at 2000rpm for 10min, and carrying out ultrasonic treatment at 1000W and 90 ℃ for 1 hour to obtain the attapulgite dispersion.

Adding 4 parts of the master batch prepared in the embodiment 11-14 into 100 parts of polypropylene respectively, and performing twin-screw extrusion granulation: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The surface of the sample was smooth, and the tensile strength and impact strength were measured, and the results are shown in Table 7.

TABLE 7

It can be seen from table 7 that the performance of the prepared calcium carbonate master batch is reduced due to the excessively long or short ultrasonic time and stirring time, the prepared attapulgite has different bonding properties due to different dispersion processes, and meanwhile, the attapulgite has a unique microstructure after being subjected to the specific treatment of the invention, the attapulgite has a diameter of 20-70 nm and a length of 0.8-1 micron needle shape, and is easy to be directionally arranged in a certain direction in the plastic processing process, so that the strength of the plastic in the directional direction is improved, and meanwhile, the attapulgite with the unique microstructure is combined with spherical particles of the inorganic filler due to the fact that crystal bundles in the attapulgite are randomly and alternately arranged in the space structure of the attapulgite, the microstructure among the crystal bundles is loose, and the spherical particles of the inorganic filler are combined, so that the effect of synergistically increasing the strength of the plastic is achieved. When the dispersion treatment mode is adopted, the difference may exist in the microstructure of the attapulgite, and the performance of the prepared calcium carbonate master batch is reduced.

Example 15

Adding 4 parts of 2000-mesh calcium carbonate into 100 parts of polypropylene respectively, and performing extrusion granulation by adopting a double screw: the processing temperature is 160-190 ℃; injecting to obtain a sample band, wherein the injection temperature is 190-200 ℃. The tensile strength and impact strength were measured and the results are shown in Table 8.

TABLE 8

	Example 5	Example 15
			Tensile Strength (MPa)	31.7	29.2
Impact Strength (kJ/m)²)	15.7	13.4

It can be seen from table 8 that when attapulgite is not added, only 2000 mesh calcium carbonate is added, the tensile strength and impact strength of the prepared sample strip are reduced, and it is possible that the attapulgite has a unique microstructure after being subjected to the specific treatment of the present invention, the attapulgite has a diameter of 20 to 70nm and a needle shape with a length of 0.8 to 1 μm, and is easily oriented in a certain direction during the plastic processing process, so as to improve the strength of the plastic in the orientation direction.

The attapulgite treated by the method has a unique microstructure, the diameter of the attapulgite is 20-70 nm, the length of the attapulgite is 0.8-1 micron needle-shaped, and the attapulgite is easy to be directionally arranged according to a certain direction in the plastic processing process, so that the strength of plastic in the directional direction is improved, and meanwhile, the attapulgite with the unique microstructure is combined with spherical particles of inorganic filler in combination with a spherical particle inorganic filler probably because crystal bundles in the attapulgite are randomly and alternately arranged in a spatial structure and the microstructure among the crystal bundles is loose, so that the effect of synergistically increasing the strength of the plastic is achieved.

The invention has the advantages that the spherical particles of the inorganic filler with the size of not less than 800 meshes and the rigid spherical particles cause the matrix plastic to be silvered to absorb energy, thereby playing a toughening effect and avoiding the defect that other master batches only play a single reinforcing or toughening effect due to only one filler.

The invention adopts the attapulgite as the binder, does not add any macromolecular component, has the content of the inorganic filler reaching 100 percent, has good universality and low cost compared with the plastic carrier master batch, can be used for nonpolar plastics and polar macromolecules, and does not have the problem of pyrolysis.

Compared with the master batch prepared by using sodium silicate as a binder, the attapulgite used in the invention has small binding power, low master batch hardness and good dispersibility in plastics, because the principle of binding the inorganic filler by the sodium silicate has chemical binding action besides dehydration binding action, the principle is as follows: na (Na)₂SiO+CO₂+HO＝H₂SiO₃+Na₂CO₃The silicic acid and the water on the surface of the inorganic filler are reacted to dehydrate newly precipitated colloid SiO₂Binding the particles together; because the inorganic fillers are bonded together through chemical bonds, the obtained master batch has high hardness and is not easy to disperse in a plastic matrix, and the attapulgite prepared by the invention is used as a binder and has only dehydration and bonding effects and no chemical bonding effect.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. A preparation method of carrier-free plastic filling master batch is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

adding attapulgite into deionized water, heating to 60-90 ℃, adding metaphosphoric acid, stirring, and performing ultrasonic treatment for 1-3 h to obtain an attapulgite dispersion liquid;

adding an inorganic filler into the attapulgite dispersion liquid, mixing at 150-250 rpm for 1min, and then mixing at 800-2000 rpm for 5min to obtain a mixed material;

and (3) putting the mixed material into an extruder for normal temperature extrusion, wherein the extrusion pressure is 2-5 MPa, the diameter of the extruded particles is controlled to be 1-3mm, the length-diameter ratio is controlled to be 2-4, and the extruded particles are dried at the temperature of 105-170 ℃ for 0.5-1.5 h to obtain the carrier-free plastic filling master batch.

2. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: and adding metaphosphoric acid and stirring, wherein the stirring speed is 800-2000 rpm, and the stirring time is 5-10 min.

3. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: and carrying out ultrasonic treatment for 1-3 h, wherein the ultrasonic power is 1200-2000W, and the temperature is 60-90 ℃.

4. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: the attapulgite is characterized in that the wet sieve residue of a 200-mesh sieve is less than or equal to 2.5 percent, the dry sieve residue of a 100-mesh sieve is less than or equal to 2.0 percent, and the water content is less than or equal to 15 percent.

5. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: and obtaining the attapulgite dispersion liquid, wherein the mass ratio of the attapulgite to the deionized water to the metaphosphoric acid in the attapulgite dispersion liquid is 40: 60-160: 0.5 to 1.

6. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: the inorganic filler comprises one or more of calcium carbonate, titanium dioxide, wollastonite, magnesium hydroxide or aluminum hydroxide.

7. The method for preparing the carrier-free plastic filling masterbatch according to claim 6, wherein the method comprises the following steps: the inorganic filler is characterized in that the shape is spherical, and the grain diameter is not less than 800 meshes.

8. The method for preparing the carrier-free plastic filling masterbatch according to claim 1, wherein the method comprises the following steps: adding an inorganic filler into the attapulgite dispersion liquid, wherein the mass ratio of the inorganic filler to the attapulgite dispersion liquid is 100: 5 to 25.