CN114085552A - Modified wollastonite, preparation method thereof and application thereof in fluororubber - Google Patents

Modified wollastonite, preparation method thereof and application thereof in fluororubber Download PDF

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CN114085552A
CN114085552A CN202111357347.8A CN202111357347A CN114085552A CN 114085552 A CN114085552 A CN 114085552A CN 202111357347 A CN202111357347 A CN 202111357347A CN 114085552 A CN114085552 A CN 114085552A
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wollastonite
coupling agent
silane coupling
slurry
preparation
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宋波
彭鹤松
李海滨
肖毓秀
陈超
王光硕
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Jiangxi Guangyuan Sales Co ltd
Lianzhou Guangyuan Calcium Carbonate Co ltd
Jiangxi Guangyuan Chemical Co Ltd
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Jiangxi Guangyuan Sales Co ltd
Lianzhou Guangyuan Calcium Carbonate Co ltd
Jiangxi Guangyuan Chemical Co Ltd
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Priority to CN202111357347.8A priority Critical patent/CN114085552A/en
Publication of CN114085552A publication Critical patent/CN114085552A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/28—Compounds of silicon
    • C09C1/30—Silicic acid
    • C09C1/3081—Treatment with organo-silicon compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
    • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/19—Oil-absorption capacity, e.g. DBP values
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/21—Attrition-index or crushing strength of granulates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
    • C01P2006/65—Chroma (C*)

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  • Pigments, Carbon Blacks, Or Wood Stains (AREA)

Abstract

The invention belongs to the technical field of wollastonite fillers, and particularly relates to modified wollastonite, a preparation method thereof and application thereof in fluororubber. The preparation method provided by the invention comprises the following steps: mixing wollastonite slurry and composite silane coupling agent hydrolysate, and performing surface modification treatment to obtain modified wollastonite, wherein the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent comprises an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, the mass percentage of wollastonite in the wollastonite slurry is less than or equal to 25%, and the mass ratio of the composite silane coupling agent to the wollastonite is more than or equal to 1.2%. The preparation method provided by the invention has good surface modification effect of the modified wollastonite and good reinforcement property when preparing the fluororubber, and the prepared fluororubber has excellent tensile strength and elongation at break.

Description

Modified wollastonite, preparation method thereof and application thereof in fluororubber
Technical Field
The invention belongs to the technical field of wollastonite fillers, and particularly relates to modified wollastonite, a preparation method thereof and application thereof in fluororubber.
Background
The fluororubber is a synthetic polymer elastomer having fluorine atoms in carbon atoms in the main chain or side chain. Due to the introduction of fluorine atoms, the rubber has excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance and atmospheric aging resistance, is widely applied in the fields of aerospace, aviation, automobiles, petroleum, household appliances and the like, and is a key material which cannot be replaced in national defense advanced industry.
Fluororubbers generally consist of raw rubber, a vulcanization system, an acid acceptor and a reinforcing system to form various practical formulas, wherein the reinforcing system generally uses modified wollastonite or diatomite as a semi-reinforcing agent, and the effect of the modified wollastonite is the best.
At present, modified wollastonite is modified by a modifying agent such as stearic acid, an aluminate coupling agent or a silane coupling agent in a dry method, but the modifying agent has poor coating effect and undesirable modifying effect, and the problem that the fluororubber produced by using the modified wollastonite obtained by the conventional dry method modification method as a semi-reinforcing agent of the fluororubber has poor tensile strength and elongation at break is solved.
Disclosure of Invention
In view of the above, the invention provides modified wollastonite and a preparation method and application thereof in fluororubber, the modified wollastonite provided by the invention has good surface modification effect, good compatibility with resin or rubber, good reinforcement during fluororubber preparation, and the prepared fluororubber has excellent tensile strength and elongation at break.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of modified wollastonite, which comprises the following steps:
mixing wollastonite slurry and composite silane coupling agent hydrolysate, and performing surface modification treatment to obtain modified wollastonite, wherein the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent comprises an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, amino in the ethoxy aminosilane coupling agent comprises a primary amino group and/or a secondary amino group, the mass percent of wollastonite in the wollastonite slurry is less than or equal to 25%, and the mass ratio of the composite silane coupling agent to wollastonite is more than or equal to 1.2%.
Preferably, the mass ratio of the ethoxyaminosilane coupling agent to the gamma- (2, 3-glycidoxy) propyl trimethoxy silane coupling agent is (5-6): 1.
Preferably, the mass ratio of the composite silane coupling agent to water to the lower alcohol is (20-25): (7-9): 67-72).
Preferably, the heat preservation temperature of the surface modification treatment is 70-90 ℃, and the heat preservation time of the surface modification treatment is 20-30 min.
Preferably, the preparation method of the wollastonite slurry comprises the following steps:
grinding the wollastonite concentrate by using an airflow mill to obtain wollastonite coarse powder;
mixing the wollastonite coarse powder with water to obtain wollastonite coarse powder slurry;
and carrying out wet grinding on the wollastonite coarse powder slurry to obtain the wollastonite slurry, wherein the rotating speed of a stirring mill during the wet grinding is 1800-2200 rpm.
Preferably, the feeding speed of the wollastonite coarse powder slurry during the wet grinding is 6-8L/min.
Preferably, when the jet mill grinds, the pressure of air is 0.65-1.2 MPa, and the flow velocity of air is 40-45 m3And min, wherein the grinding power of the jet mill is 200-300 kW.
Preferably, the wet grinding has a packing rate of a grinding medium of 70 to 75%, the grinding medium is zirconia grinding beads, and the particle size of the zirconia grinding beads is 1.2 to 2 mm.
The invention provides modified wollastonite prepared by the preparation method in the technical scheme.
The invention provides application of the modified wollastonite in the technical scheme in fluororubber.
The invention provides a preparation method of modified wollastonite, which comprises the following steps: mixing wollastonite slurry and composite silane coupling agent hydrolysate, and performing surface modification treatment to obtain modified wollastonite, wherein the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent comprises an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, amino in the ethoxy aminosilane coupling agent comprises a primary amino group and/or a secondary amino group, the mass percent of wollastonite in the wollastonite slurry is less than or equal to 25%, and the mass ratio of the composite silane coupling agent to wollastonite is more than or equal to 1.2%. The preparation method provided by the invention adopts composite silane coupling agent hydrolysate to carry out surface modification treatment on the wollastonite, the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent comprises an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, amino in the ethoxy aminosilane coupling agent comprises a primary amino group and/or a secondary amino group, and the composite silane hydrolysate adopts the ethoxy aminosilane coupling agent containing the primary amino group and/or the secondary amino group as a raw material, so that the composite silane coupling agent hydrolysate is alkaline, one end of the silane coupling agent in the hydrolysate forms silanol which is subjected to hydrolytic condensation reaction with a hydroxyl group on the surface of the wollastonite, connecting an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent on the surface of the wollastonite so as to modify the surface of the wollastonite. According to the invention, the surface of the wollastonite can be fully modified by compounding the ethoxy aminosilane coupling agent and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent and controlling the mass ratio of the composite silane coupling agent to the wollastonite to be more than or equal to 1.2%. Meanwhile, the mass percent of wollastonite in the wollastonite slurry is controlled to be less than or equal to 25 percent, the viscosity of the wollastonite slurry is ensured to be small, wollastonite in the slurry is not easy to agglomerate, and when the wollastonite in the wollastonite slurry is subjected to surface modification with the composite silane coupling agent in the composite silane coupling agent hydrolysate, hydroxyl groups on the surface of the wollastonite can react with the silane coupling agent as many as possible, so that the modification effect is good. Therefore, the preparation method provided by the invention has the advantages that the modified wollastonite has good surface modification effect and good compatibility with resin or rubber, the reinforcing property is good when the fluororubber is prepared, and the prepared fluororubber has excellent tensile strength and elongation at break. The results of the examples show that the fluororubber prepared by using the modified wollastonite prepared by the invention as the Banban reinforcing agent has excellent mechanical properties, the tensile strength is more than or equal to 13.2MPa, and the elongation at break is more than or equal to 252%.
The preparation method provided by the invention has simple steps and is suitable for industrial production.
Drawings
Fig. 1 is a flow chart of a preparation process provided by an embodiment of the invention.
Detailed Description
The invention provides a preparation method of modified wollastonite, which comprises the following steps:
mixing wollastonite slurry and composite silane coupling agent hydrolysate, and performing surface modification treatment to obtain modified wollastonite, wherein the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent is an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, amino in the ethoxy aminosilane coupling agent comprises a primary amino group and/or a secondary amino group, the mass percentage of wollastonite in the wollastonite slurry is not more than 25%, and the mass ratio of the composite silane coupling agent to wollastonite is not less than 1.2%.
In the present invention, the starting materials are all commercially available products having the numerical values of those skilled in the art, unless otherwise specified.
The invention mixes wollastonite slurry and compound silane coupling agent hydrolysate and carries out surface modification treatment to obtain modified wollastonite.
In the present invention, the mass percentage of wollastonite in the wollastonite slurry is not more than 25%, preferably 20 to 25%, and in the embodiment of the present invention, it may be 20%, 22%, or 25%.
In the present invention, the preparation method of the wollastonite slurry preferably comprises the following steps:
grinding the wollastonite concentrate by using an airflow mill to obtain wollastonite coarse powder;
mixing the wollastonite coarse powder with water to obtain wollastonite coarse powder slurry;
and carrying out wet grinding on the wollastonite coarse powder slurry to obtain the wollastonite slurry, wherein the rotating speed during the wet grinding is 1800-2200 rpm.
The invention preferably grinds the wollastonite concentrate through an air flow mill to obtain wollastonite coarse powder.
In the invention, the mass percent of the silicon dioxide in the wollastonite ore concentrate is preferably not less than 51 percent, and more preferably 51.75 percent. In the invention, the mass percent of calcium oxide in the wollastonite ore concentrate is preferably equal to or more than 44.5%, and more preferably 48.25%.
In the invention, the particle size of the wollastonite concentrate is preferably 1.7-5 mm, and more preferably 2-4 mm. The invention has no special requirement on the source of the wollastonite, and in the specific embodiment of the invention, the wollastonite concentrate is a long fiber wollastonite concentrate.
The wollastonite concentrate is preferably subjected to pretreatment, and in the invention, the pretreatment preferably comprises the following steps: and washing, drying, coarse crushing and screening the wollastonite in sequence. In the invention, the wollastonite is preferably mixed with water for washing, in the invention, the washing frequency is preferably 2, the invention has no special requirement on the specific implementation process of the washing, and the impurities on the surface of the wollastonite are removed by washing.
The washed wollastonite is preferably dried in the present invention, and the specific manner of drying is preferably drying in the air.
In the invention, the wollastonite after being dried is preferably coarsely crushed. In the present invention, the coarse crushing preferably comprises: and sequentially carrying out first section jaw crushing and second section jaw crushing. In the invention, when the jaw crusher is used for the first section of jaw crushing, the power of the jaw crusher is preferably 25-35 kW, more preferably 30kW, and the rotating speed of a main shaft of the jaw crusher is preferably 250-300 r/min, more preferably 275 r/min. In the invention, during the second-stage jaw crushing, the power of the jaw crusher is preferably 15-20 kW, more preferably 18.5kW, and the rotating speed of a main shaft of the jaw crusher is preferably 250-350 r/min, more preferably 300 r/min. The invention has no special requirements for the specific implementation process of the screening. The particle size of the wollastonite is controlled to be 1.7-5 mm through coarse crushing and screening.
In the invention, the pressure of air during the air flow grinding is preferably 0.65-1.2 MPa, and more preferably 0.7-1.1 MPa. In the invention, the flow velocity of the air is preferably 40-45 m3Min, more preferably 42 to 43m3And/min. In the invention, the power of the jet mill grinding is preferably 200-300 kW, and more preferably 250-280 kW.
In the invention, the particle size of the wollastonite coarse powder is preferably 38 to 45 μm.
The invention preferably prepares wollastonite coarse powder by processing the wollastonite concentrate through air current grinding, and controls the pressure of air during the air current grindingThe force is 0.65-1.2 MPa, and the flow rate of air is 40-45 m3And min, wherein the grinding power of the airflow mill is 200-300 kW, and the needle-shaped appearance of the wollastonite can be effectively maintained to obtain wollastonite coarse powder with the needle-shaped appearance.
After the wollastonite coarse powder is obtained, the wollastonite coarse powder and water are preferably mixed to obtain a wollastonite coarse powder slurry in the present invention.
In the invention, the mass percentage of the wollastonite coarse powder in the wollastonite coarse powder slurry is less than or equal to 25%, preferably 20-25%, and more preferably 21.5-23%.
In the present invention, the mixing of the wollastonite coarse powder and water is preferably carried out in a compounding tank. The invention has no special requirement on the concrete implementation process of mixing the wollastonite coarse powder and the water.
After the wollastonite coarse powder slurry is obtained, the wollastonite coarse powder slurry is preferably conveyed from the batching barrel to a buffer barrel by a diaphragm pump and stored.
After the wollastonite coarse powder slurry is obtained, the wollastonite coarse powder slurry is preferably subjected to wet grinding to obtain the wollastonite slurry, wherein the rotation speed during the wet grinding is 1800-2200 rpm.
In the present invention, the wet grinding is preferably performed in a vertical stirring mill. In a specific embodiment of the invention, the volume of the vertical stirring mill is 3600L.
In the invention, the feeding speed of the wollastonite coarse powder slurry in the wet grinding is preferably 6-8L/min, and more preferably 6.2-7.5L/min. The wollastonite coarse powder slurry is preferably conveyed to the vertical stirring mill from the buffer barrel, and the wollastonite coarse powder slurry is preferably conveyed by a diaphragm pump, wherein the feeding speed of the diaphragm pump is preferably 10-15 Hz, and more preferably 11-13 Hz.
In the present invention, the rotation speed of the stirring mill during the wet grinding is preferably 1800 to 2200rpm, more preferably 1950 to 2150 rpm. In the invention, the grinding time is preferably 30-60 min, and more preferably 40-50 min.
In the present invention, the filling of the grinding mediaThe ratio is preferably 70 to 75%, more preferably 71.5 to 73%. In the invention, the grinding medium is preferably zirconia grinding beads, and the particle size of the zirconia grinding beads is preferably 1.2-2 mm, and more preferably 1.5-1.8 mm. In the present invention, the zirconia grinding beads have a true density of preferably 6g/cm3。
In the invention, the wollastonite in the wollastonite slurry is preferably ultrafine powder by controlling the feeding speed of the diaphragm pump to be preferably 10 to 15Hz and controlling the rotation speed of the stirring mill to be preferably 1800 to 2200rpm, and in the invention, the length-diameter ratio of the wollastonite in the wollastonite slurry is preferably (4 to 5):1, and the D50 is preferably 3.1 to 3.3 μm.
According to the invention, preferably, a diaphragm pump is adopted to convey the wollastonite slurry to the reaction kettle for surface modification treatment.
In the invention, the wollastonite slurry is preferably subjected to ultrasonic treatment and then mixed with the composite silane coupling agent hydrolysate.
In the invention, the ultrasonic power during ultrasonic treatment is preferably 25-30 kHz, and more preferably 28 kHz. In the invention, the ultrasonic time during ultrasonic treatment is preferably 3-5 min. In the invention, the temperature of the ultrasonic treatment is preferably 70-90 ℃.
Before the wollastonite slurry is mixed with the composite silane coupling agent hydrolysate, the wollastonite slurry is subjected to ultrasonic treatment, the ultrasonic power is controlled to be 25-30 kHz, the ultrasonic time is 3-5 min, the ultrasonic treatment temperature is 70-90 ℃, the wollastonite in the wollastonite slurry can be uniformly dispersed, and the wollastonite can be favorably reacted with the composite silane coupling agent hydrolysate.
In the invention, the composite silane coupling agent hydrolysate is obtained by hydrolyzing the composite silane coupling agent in a mixed solvent of water and low-carbon alcohol.
In the present invention, the complex silane coupling agent includes an ethoxyaminosilane coupling agent and a γ - (2, 3-glycidoxy) propyltrimethoxysilane coupling agent, and more preferably includes an ethoxyaminosilane coupling agent and a γ - (2, 3-glycidoxy) propyltrimethoxysilane coupling agent. In the present invention, the amino group in the ethoxyaminosilane coupling agent preferably includes a primary amino group and/or a secondary amino group.
In the invention, the mass ratio of the ethoxyaminosilane coupling agent to the gamma- (2, 3-glycidoxy) propyltrimethoxysilane coupling agent is preferably (5-6): 1, and more preferably (5.5-5.8): 1.
In the invention, the mass ratio of the composite silane coupling agent, water and lower alcohol is preferably (20-25): 7-9): 67-72, and more preferably (21.5-24): 7.5-8.5): 68-70.
In the invention, the compound silane hydrolysate comprises a raw material of an ethoxy aminosilane coupling agent containing a primary amino group and/or a secondary amino group, and the compound silane coupling agent hydrolysate can be alkaline, so that silanol is formed at one end of the silane coupling agent in the hydrolysate, and the silanol and hydroxyl groups on the surface of wollastonite undergo hydrolytic condensation reaction to modify the surface of the wollastonite.
In the present invention, the preparation method of the composite silane coupling agent hydrolysate preferably comprises the following steps:
premixing the ethoxy aminosilane coupling agent, water and low-carbon alcohol to obtain an aminosilane solution;
and finally mixing the aminosilane solution and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent for hydrolysis reaction to obtain the composite silane coupling agent hydrolysate.
According to the invention, the ethoxy aminosilane coupling agent, water and low-carbon alcohol are preferably premixed to obtain an aminosilane solution. In a specific embodiment of the present invention, the lower alcohol is specifically ethanol. In the invention, the premixing is preferably carried out at room temperature, the premixing is preferably carried out under the condition of stirring, and the stirring time is preferably 25-30 min. In the present invention, the order of premixing the ethoxyaminosilane coupling agent, water, and lower alcohol is preferably that the water and the lower alcohol are mixed to obtain a mixed solvent, and the mixed solvent is mixed with the ethoxyaminosilane coupling agent.
After obtaining the aminosilane solution, the aminosilane solution and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent are finally mixed for hydrolysis reaction to obtain the composite silane coupling agent hydrolysate. In the present invention, the final mixing is preferably performed at room temperature, the final mixing is preferably performed under stirring, in the present invention, the hydrolysis reaction is preferably performed at room temperature, the hydrolysis reaction is preferably performed under stirring, and after the final mixing, the stirring time of the hydrolysis reaction is preferably 3 to 4 hours.
In the invention, the mass ratio of the composite silane coupling agent to the wollastonite is more than or equal to 1.2%, and preferably 1.2-2.5%.
The invention has no special requirements on the specific implementation process of mixing the wollastonite slurry and the composite silane coupling agent hydrolysate.
In the invention, the heat preservation temperature of the surface modification treatment is preferably 70-90 ℃, and more preferably 75-85 ℃. In the invention, the heat preservation time of the surface modification treatment is preferably 20-30 min, and more preferably 23-25 min. In the present invention, the surface modification treatment is preferably performed under stirring conditions, and the rotation speed of the stirring is preferably 200 to 400rpm, and more preferably 250 to 300 rpm. In an embodiment of the present invention, the volume of the reaction vessel for surface modification treatment is preferably 1000L.
In the invention, after the surface modification treatment, modified wollastonite slurry is obtained, and after the surface modification treatment, the invention preferably further comprises post-treatment of the modified wollastonite slurry. In the present invention, the post-treatment preferably comprises: drying, dispersing, grading and packaging in sequence. In the invention, the drying is preferably spray drying, and the feeding temperature during the spray drying is preferably 205-220 ℃, and more preferably 210-215 ℃. In the invention, the discharge temperature during spray drying is preferably 95-105 ℃, and more preferably 100 ℃.
The invention preferably breaks up, grades and packages the dried solid product, and has no special requirements on the specific implementation process of the breaking up, grading and packaging.
The invention provides modified wollastonite prepared by the preparation method in the technical scheme. In the invention, the D50 of the modified wollastonite is preferably 3.18 to 3.27 μm. The length-diameter ratio of the modified wollastonite is preferably (4.3-5): 1.
The invention provides application of the modified wollastonite in the technical scheme in fluororubber.
In the present invention, the modified wollastonite is preferably used as a semi-reinforcing agent for the fluororubber.
In the invention, the mass ratio of the modified wollastonite to the fluororubber raw rubber is preferably (1-2): 10, and preferably 3: 20.
The invention has no special requirements on the composition formula of the fluororubber.
The invention has no special requirements on the preparation method of the fluororubber.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
According to the process flow shown in figure 1, high-purity long-fiber wollastonite concentrate with the silicon dioxide content of more than 51 percent and the calcium oxide content of more than 44.5 percent is selected, washed with water and dried, and then sequentially crushed by a first section of jaw crusher, wherein the power of the jaw crusher is 30kW, and the rotating speed of a main shaft of the jaw crusher is 275 r/min; and (3) carrying out second-stage jaw crushing, wherein the power of a jaw crusher is 18.5kW, the rotating speed of a main shaft of the jaw crusher is 300r/min, and then sieving by using a sieve of 5-10 meshes to obtain long fiber wollastonite concentrate particles with the particle size of 1.7-5 mm.
Delivering wollastonite fine ore particles into an air flow mill for grinding, wherein the pressure of air is 1.2MPa, and the flow rate of the air is 41.5m3And/min, wherein the grinding power of the jet mill is 250kW, and long fiber wollastonite coarse powder with the particle size of 38-45 microns is obtained.
Adding water and long fiber wollastonite coarse powder into a slurry preparation barrel to prepare silica fume with the wollastonite percentage of 20 percentA stone meal slurry. Conveying wollastonite coarse powder slurry into a buffer barrel by using a No. 1 diaphragm pump, and conveying the wollastonite coarse powder slurry into a vertical stirring mill by using a No. 2 diaphragm pump for wet grinding; the feeding frequency of the No. 2 diaphragm pump is 15Hz, the rotating speed of the stirring mill is 1800rpm, the grinding time is 45min, the volume of the vertical stirring mill is 3600L, the filling rate of the zirconia grinding beads in the stirring mill is 70 percent, and the real density of the zirconia grinding beads is 6.0g/cm3And the diameter is 1.2 mm. Grinding to obtain the superfine acicular wollastonite slurry.
And stirring and premixing the ethoxy aminosilane coupling agent containing the primary amino group and the secondary amino group, water and ethanol for 25min to obtain an aminosilane solution, and stirring and finally mixing the aminosilane solution and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent for 4h to obtain the composite silane coupling agent hydrolysate. Wherein, the mass percent of the ethoxy aminosilane coupling agent containing primary amino group and secondary amino group is 16.7%, the mass percent of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent is 3.3%, the mass percent of water is 7%, and the mass percent of ethanol is 73% at the end of the composite silane coupling agent hydrolysate.
Conveying the wollastonite slurry into a reaction kettle through a No. 3 diaphragm pump, heating to 70 ℃, performing ultrasonic dispersion treatment for 3min with the ultrasonic power of 28kHz, adding composite silane coupling agent hydrolysate which is 6 percent of the mass of wollastonite powder in the wollastonite slurry to perform surface modification treatment, performing surface modification treatment at the constant temperature of 70 ℃ for 20min, and finally obtaining the superfine needle-shaped modified wollastonite slurry, wherein the rotating speed of blades of the reaction kettle is 100 rpm. And (3) spray-drying the superfine needle-like modified wollastonite slurry, wherein the feeding temperature during spray-drying is 220 ℃, the discharging temperature is 105 ℃, obtaining a solid product, and then scattering, grading and packaging the solid product to obtain the superfine needle-like modified wollastonite product. The D50 of the superfine needle-like modified wollastonite product measured by a Malvern laser particle size analyzer 3000E is 3.27 mu m.
Example 2
According to the process flow shown in figure 1, high-purity long-fiber wollastonite concentrate with the silicon dioxide content of more than 51 percent and the calcium oxide content of more than 44.5 percent is selected, washed with water and dried, and then sequentially crushed by a first section of jaw crusher, wherein the power of the jaw crusher is 30kW, and the rotating speed of a main shaft of the jaw crusher is 275 r/min; and (3) carrying out second-stage jaw crushing, wherein the power of a jaw crusher is 18.5kW, the rotating speed of a main shaft of the jaw crusher is 300r/min, and then sieving by using a sieve of 5-10 meshes to obtain long fiber wollastonite concentrate particles with the particle size of 1.7-5 mm.
Delivering wollastonite fine ore particles into an air flow mill for grinding, wherein the pressure of air is 1.2MPa, and the flow rate of the air is 41.5m3And/min, wherein the grinding power of the jet mill is 250kW, and long fiber wollastonite coarse powder with the particle size of 38-45 microns is obtained.
Adding water and long fiber wollastonite coarse powder into a pulp preparation barrel to prepare wollastonite coarse powder pulp with the wollastonite percentage of 22 percent. Conveying wollastonite coarse powder slurry into a buffer barrel by using a No. 1 diaphragm pump, and conveying the wollastonite coarse powder slurry into a vertical stirring mill by using a No. 2 diaphragm pump for wet grinding; the feeding frequency of the No. 2 diaphragm pump is 17Hz, the rotating speed of the stirring mill is 1950rpm, the grinding time is 45min, the volume of the vertical stirring mill is 3600L, the filling rate of the zirconia grinding beads in the stirring mill is 72 percent, and the real density of the zirconia grinding beads is 6.0g/cm3And the diameter is 2 mm. Grinding to obtain the superfine acicular wollastonite slurry.
And stirring and premixing the ethoxy aminosilane coupling agent containing the primary amino group and the secondary amino group, water and ethanol for 25min to obtain an aminosilane solution, and stirring and finally mixing the aminosilane solution and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent for 3.6h to obtain the composite silane coupling agent hydrolysate. Wherein, the mass percent of the ethoxy aminosilane coupling agent containing primary amino group and secondary amino group is 16.9%, the mass percent of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent is 3.1%, the mass percent of water is 8%, and the mass percent of ethanol is 7273%.
Conveying the wollastonite slurry into a reaction kettle through a No. 3 diaphragm pump, heating to 80 ℃, performing ultrasonic dispersion treatment for 4min with the ultrasonic power of 28kHz, adding composite silane coupling agent hydrolysate which is 7 percent of the mass of wollastonite powder in the wollastonite slurry to perform surface modification treatment, performing surface modification treatment at the constant temperature of 80 ℃ for 30min, and finally obtaining the superfine needle-shaped modified wollastonite slurry, wherein the rotating speed of blades of the reaction kettle is 150 rpm. And (3) spray-drying the superfine needle-like modified wollastonite slurry, wherein the feeding temperature during spray-drying is 220 ℃, the discharging temperature is 105 ℃, obtaining a solid product, and then scattering, grading and packaging the solid product to obtain the superfine needle-like modified wollastonite product. The D50 of the superfine needle-like modified wollastonite product measured by a Malvern laser particle size analyzer 3000E is 3.23 mu m.
Example 3
According to the process flow shown in figure 1, high-purity long-fiber wollastonite concentrate with the silicon dioxide content of more than 51 percent and the calcium oxide content of more than 44.5 percent is selected, washed with water and dried, and then sequentially crushed by a first section of jaw crusher, wherein the power of the jaw crusher is 30kW, and the rotating speed of a main shaft of the jaw crusher is 275 r/min; and (3) carrying out second-stage jaw crushing, wherein the power of a jaw crusher is 18.5kW, the rotating speed of a main shaft of the jaw crusher is 300r/min, and then sieving by using a sieve of 5-10 meshes to obtain long fiber wollastonite concentrate particles with the particle size of 1.7-5 mm.
Delivering wollastonite fine ore particles into an air flow mill for grinding, wherein the pressure of air is 1.2MPa, and the flow rate of the air is 41.5m3And/min, wherein the grinding power of the jet mill is 250kW, and long fiber wollastonite coarse powder with the particle size of 38-45 microns is obtained.
Adding water and long fiber wollastonite coarse powder into a pulp preparation barrel to prepare wollastonite coarse powder pulp with the wollastonite percentage of 25 percent. Conveying wollastonite coarse powder slurry into a buffer barrel by using a No. 1 diaphragm pump, and conveying the wollastonite coarse powder slurry into a vertical stirring mill by using a No. 2 diaphragm pump for wet grinding; the feeding frequency of the No. 2 diaphragm pump is 15Hz, the rotating speed of the stirring mill is 2150rpm, the grinding time is 45min, the volume of the vertical stirring mill is 3600L, the filling rate of the zirconia grinding beads in the stirring mill is 75 percent, and the real density of the zirconia grinding beads is 6.0g/cm3And the diameter is 1.5 mm. Grinding to obtain the superfine acicular wollastonite slurry.
And stirring and premixing the ethoxy aminosilane coupling agent containing the primary amino group and the secondary amino group, water and ethanol for 25min to obtain an aminosilane solution, and stirring and finally mixing the aminosilane solution and the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent for 3h to obtain the composite silane coupling agent hydrolysate. Wherein, the mass percent of the ethoxy aminosilane coupling agent containing primary amino group and secondary amino group is 17.2%, the mass percent of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent is 2.8%, the mass percent of water is 9%, and the mass percent of ethanol is 71% at the end of the composite silane coupling agent hydrolysate.
Conveying the wollastonite slurry into a reaction kettle through a No. 3 diaphragm pump, heating to 90 ℃, performing ultrasonic dispersion treatment for 5min with the ultrasonic power of 28kHz, adding composite silane coupling agent hydrolysate accounting for 8 percent of the mass of wollastonite powder in the wollastonite slurry to perform surface modification treatment, performing surface modification treatment at the constant temperature of 90 ℃ for 40min, and finally obtaining the superfine needle-shaped modified wollastonite slurry, wherein the rotating speed of blades of the reaction kettle is 300 rpm. And (3) spray-drying the superfine needle-like modified wollastonite slurry, wherein the feeding temperature during spray-drying is 220 ℃, the discharging temperature is 105 ℃, obtaining a solid product, and then scattering, grading and packaging the solid product to obtain the superfine needle-like modified wollastonite product. The D50 of the superfine needle-like modified wollastonite product measured by a Malvern laser particle size analyzer 3000E is 3.18 mu m.
Test example 1
The modified wollastonite powder products prepared in examples 1-3 are subjected to related index detection according to JC/T535-2007, and the related indexes and the test results are shown in Table 1.
TABLE 1 Performance test data for modified wollastonite powder products produced in examples 1 to 3
Figure BDA0003357790090000111
Figure BDA0003357790090000121
As can be seen from Table 1, the modified wollastonite powder product prepared by the present invention has uniform particle size distribution, fine particle size and needle-like structure, and all properties are in a good level.
Application example
The modified wollastonite powder product prepared in the embodiment 1 to 3 is applied to fluororubber. The basic formulation of the fluororubbers is shown in Table 2. The preparation method of the fluororubber comprises the following steps: mixing raw fluororubber, an acid-receiving agent, high-activity magnesium oxide, modified wollastonite, Carl wax, a vulcanizing agent, an accelerator and a release agent, controlling the roll temperature to be 40-60 ℃ during mixing, and then carrying out secondary vulcanization, wherein the primary vulcanization temperature is 170 ℃, the primary vulcanization time is 10min, the secondary vulcanization temperature is 230 ℃, and the vulcanization time is 24 h.
TABLE 2 formulation of fluororubbers
Figure BDA0003357790090000122
Test example 2
The hardness and mechanical property of the fluororubbers prepared by the corresponding examples are detected according to GB/T531.1-2008 and GB/T528-2009. The test results are shown in table 3. Wherein: and (3) testing conditions are as follows: the test temperature was 177 ℃ and the test time was 600 Sec.
TABLE 3 data for the measurement of the properties of fluororubbers produced using the modified wollastonite powders of examples 1 to 3 as fillers
Figure BDA0003357790090000131
Note: TS2 is: the time corresponding to the curve rising from the lowest torque by 0.2Nm from the beginning of the experiment is min; TC10 is: glue burning time; TC90 is: the positive vulcanization time of the process; (ML) Minimum is: a lowest torque; (MH) Maximum is: the maximum torque.
As can be seen from Table 3, the superfine needle-like modified wollastonite produced in this example can meet the performance index requirements of fluororubber. The fluororubber prepared by using the modified wollastonite prepared by the invention as the Banban reinforcing agent has excellent mechanical property, the tensile strength is more than or equal to 13.2MPa, and the elongation is more than or equal to 252%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A preparation method of modified wollastonite is characterized by comprising the following steps:
mixing wollastonite slurry and composite silane coupling agent hydrolysate, and performing surface modification treatment to obtain modified wollastonite, wherein the composite silane coupling agent hydrolysate is obtained by hydrolyzing a composite silane coupling agent in a mixed solvent of water and low-carbon alcohol, the composite silane coupling agent comprises an ethoxy aminosilane coupling agent and a gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, amino in the ethoxy aminosilane coupling agent comprises a primary amino group and/or a secondary amino group, the mass percent of wollastonite in the wollastonite slurry is less than or equal to 25%, and the mass ratio of the composite silane coupling agent to wollastonite is more than or equal to 1.2%.
2. The preparation method according to claim 1, wherein the mass ratio of the ethoxyaminosilane coupling agent to the gamma- (2, 3-glycidoxy) propyltrimethoxysilane coupling agent is (5-6): 1.
3. The method according to claim 1 or 2, wherein the mass ratio of the composite silane coupling agent to water to the lower alcohol is (20-25): (7-9): (67-72).
4. The method according to claim 1, wherein the surface modification treatment is carried out at a temperature of 70 to 90 ℃ for 20 to 30 min.
5. The preparation method of claim 1, wherein the preparation method of the wollastonite slurry comprises the following steps:
grinding the wollastonite concentrate by using an airflow mill to obtain wollastonite coarse powder;
mixing the wollastonite coarse powder with water to obtain wollastonite coarse powder slurry;
and carrying out wet grinding on the wollastonite coarse powder slurry to obtain the wollastonite slurry, wherein the rotating speed of a stirring mill during the wet grinding is 1800-2200 rpm.
6. The preparation method of claim 5, wherein the feeding speed of the wollastonite coarse powder slurry during the wet grinding is 6-8L/min.
7. The method according to claim 5, wherein the air pressure is 0.65 to 1.2MPa and the air flow rate is 40 to 45m during the air jet milling3And min, wherein the grinding power of the jet mill is 200-300 kW.
8. The method according to claim 6, wherein the wet grinding has a packing ratio of 70 to 75% for a grinding medium, the grinding medium is zirconia grinding beads having a particle size of 1.2 to 2 mm.
9. Modified wollastonite produced by the production method according to any one of claims 1 to 8.
10. Use of the modified wollastonite of claim 9 in fluororubbers.
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CN115010994A (en) * 2022-05-13 2022-09-06 江西广源化工有限责任公司 Modified superfine wollastonite powder and its prepn and application

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