Inorganic nonmetal composite powder as well as preparation method and application thereof

Abstract

The invention provides inorganic nonmetal composite powder as well as a preparation method and application thereof, and belongs to the technical field of fine chemical engineering. The inorganic nonmetal composite powder is prepared by taking superfine needle-like wollastonite powder as a raw material and coating a layer of calcium silicate nanoparticles and a composite modifier on the surface of the superfine needle-like wollastonite by adopting a liquid phase deposition method. The inorganic nonmetal composite powder obtained by the invention is fine in particle size, large in specific surface area and low in oil absorption, and can improve the comprehensive mechanical property and glossiness of a PA6 composite material when being used in the PA6 composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of fine chemical engineering, and particularly relates to an inorganic non-metallic composite powder and a preparation method and application thereof. Background Art

[0002] Inorganic non-metallic composite powder is an inorganic filler with complex chemical composition, composed of more than two inorganic substances. According to its formation method, it can be divided into natural composite inorganic filler and artificial composite inorganic filler. Modern new polymer-based composites have put forward higher requirements for non-metallic mineral fillers. They not only need to be able to increase the amount and reduce the material cost, but also need to have the function of improving the performance of the filled material or reinforcing and strengthening. At present, the main technical ways to improve the performance of inorganic fillers include particle size refinement, chemical composition and crystal structure complication, and surface activation. Among them, compounding and surface modification of more than two inorganic fillers can complicate the bulk phase structure and surface activation of the filler system, and organically combine inorganic fillers with different particle shapes, chemical compositions and crystal structures. Complementing each other and cooperating with each other during filling can optimize the filling performance of inorganic fillers and better meet the requirements of high strength and high performance of composites, which is one of the main development directions of inorganic fillers in the future. However, different types of inorganic fillers have different effects on the mechanical, thermal, electrical and processing properties of filled polymer-based composites due to different particle shapes, chemical compositions, crystal structures and physicochemical properties.

[0003] Wollastonite is a chain-like metasilicate mineral, belonging to the triclinic system, with a fibrous and needle-like structure. Generally, it is acid-resistant, alkali-resistant, and chemically corrosion-resistant, with low oil absorption, low conductivity, and good insulation. It can be used as a reinforcing filler for resins to improve the performance of plastic composites. As a filler, it can be used as a reinforcing agent, which can significantly improve the tensile strength, flexural strength and hardness of the matrix material, and improve the thermal stability, dimensional stability and wear resistance of the matrix material. It is widely used in fields such as plastic modification. Although wollastonite has good filling and strengthening functions due to its needle-like structure and can improve the tensile strength and modulus of the filled material, it will cause the color of the filled material to become darker. Summary of the Invention

[0004] The purpose of the present invention is to provide an inorganic non-metallic composite powder, which has excellent filling performance and processing performance. When used in composites, it can meet the high strength and high mechanical properties required by the composites, and can also improve the gloss of the composites.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of an inorganic non-metallic composite powder, comprising the following steps:

[0007] The wollastonite ore is subjected to primary crushing, secondary crushing and dry grinding to obtain acicular wollastonite powder;

[0008] The acicular wollastonite powder, water, a composite grinding aid and a composite dispersant are mixed and subjected to wet grinding to obtain a wollastonite slurry;

[0009] Under stirring conditions, the wollastonite slurry, sodium silicate solution and calcium hydroxide are mixed for liquid-phase deposition coating to obtain a composite slurry;

[0010] The composite slurry is subjected to flash drying and depolymerization and dispersion in sequence to obtain a composite powder;

[0011] The composite powder is mixed with a composite modifier for surface modification to obtain an inorganic non-metallic composite powder.

[0012] Preferably, the silicon dioxide content of the wollastonite ore is ≥50 wt%; the rotation speed of the dry grinding is 450 - 550 r / min, and the time is 15 - 35 min; the particle size of the acicular wollastonite powder is 400 - 500 mesh.

[0013] Preferably, the mass ratio of the acicular wollastonite powder to water is 40 - 55:45 - 60;

[0014] The composite dispersant includes one or more of sodium lignosulfonate, sodium polyacrylate, polyvinyl alcohol, sodium pyrophosphate and sodium metaphosphate, and the mass of the composite dispersant is 6 - 10‰ of the mass of the acicular wollastonite powder;

[0015] The composite grinding aid includes one or more of polyhydric alcohol polymers, polyalkanolamines, triethanolamine, ethylene glycol and diethylene glycol, and the mass of the composite grinding aid is 5 - 9‰ of the mass of the acicular wollastonite powder.

[0016] Preferably, the rotation speed of the wet grinding is 2500 - 2800 r / min, the time is 1.5 - 2.5 h, and the temperature is 75 - 85°C; the solid content of the wollastonite slurry is 40 - 55 wt%, and the particle size of the materials of the wollastonite slurry is 6000 mesh.

[0017] Preferably, the mass concentration of the sodium silicate solution is 35 - 40%, the mass ratio of the acicular wollastonite powder to the mass of the sodium silicate solution is 100:35 - 45, and the mass ratio of the mass of the sodium silicate solution to the mass of calcium hydroxide is 2.6 - 3.0:1;

[0018] During the liquid-phase deposition coating, the pH of the wollastonite slurry is 10 - 12, the temperature of the liquid-phase deposition coating is 25°C; the rotation speed of the stirring is 250 - 350 r / min, and the time > 1 h.

[0019] Preferably, the inlet air temperature of the hot air in the flash drying is 250 - 300 °C, and the time is 8 - 15 min; the particle size of the composite powder obtained after depolymerization and dispersion is 2.0 - 3.0 μm.

[0020] Preferably, the composite modifier includes a silane coupling agent, a surfactant, and an aluminate coupling agent. The mass of the composite modifier is 10 - 15‰ of the mass of the acicular wollastonite powder; the temperature of the surface modification is 40 - 80 °C, and the time is 30 - 50 min.

[0021] Preferably, the silane coupling agent includes one or more of γ-methacryloxypropyltrimethoxysilane, n-octyltriethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane. The mass of the silane coupling agent is 5 - 7‰ of the mass of the acicular wollastonite powder;

[0022] The surfactant includes one or more of higher fatty alcohol polyoxyethylene ether, quaternary ammonium salt, and polyethylene glycol. The mass of the surfactant is 2 - 4‰ of the mass of the acicular wollastonite powder;

[0023] The aluminate coupling agent includes one or more of isopropyl distearoyl aluminate and isooctanol polyoxyethylene ether phosphate. The mass of the aluminate coupling agent is 3 - 5‰ of the mass of the acicular wollastonite powder.

[0024] The present invention provides an inorganic non-metallic composite powder prepared by the above preparation method.

[0025] The present invention provides the application of the above inorganic non-metallic composite powder in plastic products.

[0026] The beneficial effects of the present invention:

[0027] The present invention uses wollastonite ore as a raw material to prepare acicular wollastonite powder; by using the liquid phase deposition method, a uniform and stable layer of calcium silicate nanoparticles and a composite modifier are coated on the surface of the acicular wollastonite powder to obtain an inorganic non-metallic composite powder with fine particle size, large specific surface area, and low oil absorption, which has excellent filling performance and processing performance. As a filling material for PA6 composites, it can meet the high strength and high mechanical properties of the composites, and at the same time can improve the color of the wollastonite-filled composites.

[0028] The present invention modifies the composite powder with a composite modifier. The calcium atoms exposed in the surface structure of the composite powder combine with the hydroxyl groups that have lost hydrogen atoms in the composite modifier to form Si-O-Ca bonds, firmly adsorbing the composite modifier on the surface of the composite powder, improving the fluidity, dispersibility of the composite powder and its compatibility with the composite material during the subsequent processing, thereby improving the mechanical properties of the PA6 composite material.

[0029] In the present invention, a layer of calcium silicate nanoparticles is coated on the surface of the acicular wollastonite powder. On the one hand, the surface of the wollastonite becomes smoother, reducing light scattering, making the surface reflection of the material more uniform and the color more bright. On the other hand, after being coated with calcium silicate nanoparticles, the color of the wollastonite itself is covered, reducing its influence on the color of the composite material. Moreover, the chemical stability of the wollastonite is improved, reducing the color change caused by chemical reactions during processing or use. Detailed implementation mode

[0030] The present invention provides a method for preparing an inorganic non-metallic composite powder, comprising the following steps:

[0031] The wollastonite ore is subjected to primary crushing, secondary crushing and dry grinding to obtain acicular wollastonite powder;

[0032] The acicular wollastonite powder, water, composite grinding aid and composite dispersant are mixed and wet grinding is carried out to obtain a wollastonite slurry;

[0033] Under the condition of stirring, the wollastonite slurry, sodium silicate solution and calcium hydroxide are mixed for liquid-phase deposition coating to obtain a composite slurry;

[0034] The composite slurry is subjected to flash drying and depolymerization and dispersion in sequence to obtain a composite powder;

[0035] The composite powder is mixed with a composite modifier for surface modification to obtain an inorganic non-metallic composite powder.

[0036] Preferably, in the present invention, the wollastonite raw ore is washed and then subjected to primary crushing in a jaw crusher and a hammer crusher to obtain wollastonite coarse particles; the wollastonite coarse particles are put into a bin through an automatic feeding machine for secondary crushing to obtain wollastonite fine particles; the wollastonite fine particles are conveyed by a belt to a 2.2m * 7.2m all-ceramic inner-lined ball mill for dry grinding, and the grinding medium is alumina ceramic grinding balls to obtain acicular wollastonite powder.

[0037] In the present invention, the silicon dioxide content of the wollastonite ore is preferably ≥ 50 wt%.

[0038] In the present invention, the diameter of the wollastonite coarse particles is preferably 5 - 10 cm, more preferably 6 - 9 cm; the diameter of the wollastonite fine particles is preferably 8 - 12 mm, more preferably 9 - 11 mm.

[0039] In the present invention, the rotation speed of the dry grinding is preferably 450 - 550 r / min, more preferably 480 - 520 r / min, and the time is 15 - 35 min, more preferably 20 - 30 min.

[0040] In the present invention, the particle size of the acicular wollastonite powder is preferably 400 - 500 mesh, and more preferably 400 mesh; the acicular wollastonite represents good quality wollastonite, having characteristics such as high strength, wear resistance, and good reinforcing property.

[0041] In the present invention, it is preferred to mix the acicular wollastonite powder with water, add a composite dispersant to make it fully dispersed and uniform, pump it into a 3600L vertical stirred ball mill, add a composite grinding aid, and conduct wet grinding to obtain a wollastonite slurry.

[0042] In the present invention, the mass ratio of the acicular wollastonite powder to water is preferably 40 - 55:45 - 60, and more preferably 45 - 50:50 - 55.

[0043] In the present invention, the composite dispersant preferably includes one or more of sodium lignosulfonate, sodium polyacrylate, polyvinyl alcohol, sodium pyrophosphate, and sodium metaphosphate, and more preferably includes one or more of sodium polyacrylate, sodium pyrophosphate, and sodium metaphosphate; when the composite dispersant includes two or more of sodium lignosulfonate, sodium polyacrylate, polyvinyl alcohol, sodium pyrophosphate, and sodium metaphosphate, the present invention does not make special limitations on the mass ratio between the composite dispersants; the mass of the composite dispersant is preferably 6 - 10‰ of the mass of the acicular wollastonite powder, more preferably 7 - 9‰, and even more preferably 7.5 - 8.5‰.

[0044] In the present invention, the composite grinding aid preferably includes one or more of polyhydric alcohol polymers, polyalkanolamines, triethanolamine, ethylene glycol, and diethylene glycol, and more preferably includes one or more of ethylene glycol, polyhydric alcohol polymers, and polyalkanolamines; the polyhydric alcohol polymer (PP) and polyalkanolamine (PAA) are purchased from Beijing Zhongbo Polymer Technology Co., Ltd.; when the composite grinding aid includes two or more of polyhydric alcohol polymers, polyalkanolamines, triethanolamine, ethylene glycol, and diethylene glycol, the present invention does not make special limitations on the mass ratio between the composite grinding aids; the mass of the composite grinding aid is preferably 5 - 9‰ of the mass of the acicular wollastonite powder, more preferably 6 - 8‰, and even more preferably 6.5 - 7.5‰; in the present invention, the composite dispersant and the composite grinding aid are combined with the surface of wollastonite by electrostatic action or chemical bonding, and by changing the physical and chemical properties of the particle surface, the grinding efficiency and product quality are improved.

[0045] In the present invention, the rotation speed of the wet grinding is preferably 2500 - 2800 r / min, more preferably 2650 - 2750 r / min, the time is preferably 1.5 - 2.5 h, more preferably 2 - 2.5 h, and the temperature is preferably 75 - 85°C, more preferably 78 - 82°C.

[0046] In the present invention, the solid content of the wollastonite slurry is preferably 40-55 wt%, more preferably 45-50 wt%, and the particle size of the materials of the wollastonite slurry is preferably 6000 mesh.

[0047] In the present invention, it is preferred to transfer the wollastonite slurry into a slurry storage tank, and under the condition of stirring, add a sodium silicate solution and calcium hydroxide to carry out liquid-phase deposition coating to obtain a composite slurry.

[0048] In the present invention, the mass concentration of the sodium silicate solution is preferably 35-40%, more preferably 36-38%; the mass ratio of the acicular wollastonite powder to the mass of the sodium silicate solution is preferably 100:35-45, more preferably 100:38-42; the mass ratio of the mass of the sodium silicate solution to the mass of calcium hydroxide is preferably 2.6-3.0:1, more preferably 2.7-2.9:1.

[0049] In the present invention, the rotation speed of the stirring is preferably 250-350 r / min, more preferably 280-330 r / min, and the time is preferably >1 h, more preferably 1.5 h.

[0050] In the present invention, during the liquid-phase deposition coating, the pH of the wollastonite slurry is preferably 10-12, more preferably 12; the temperature of the liquid-phase deposition coating is preferably 25 °C.

[0051] In the present invention, it is preferred to pump the composite slurry into a flash dryer, and carry out flash drying with clean hot air. The dried powder enters a deflocculating and dispersing machine through a spiral auger feeder for deflocculation and dispersion, and is collected by a cloth bag to obtain a composite powder.

[0052] In the present invention, in the flash drying, the inlet air temperature of the hot air is preferably 250-300 °C, more preferably 260-280 °C, and the time is preferably 8-15 min, more preferably 10-12 min.

[0053] In the present invention, the particle size of the composite powder obtained after deflocculation and dispersion is preferably 2.0-3.0 μm. Deflocculation and dispersion are to disperse the agglomerated powder and maintain the particle size of the primary particles.

[0054] In the present invention, it is preferred to transport the composite powder to a surface modifier, add a composite modifier, and carry out surface modification treatment to obtain an inorganic non-metallic composite powder.

[0055] In the present invention, the composite modifier preferably includes a silane coupling agent, a surfactant, and an aluminate coupling agent. The mass of the composite modifier is preferably 10 to 15‰ of the mass of the acicular wollastonite powder, and more preferably 11 to 13‰. Adding the composite modifier to modify the composite powder, the calcium atoms exposed in the surface structure of the composite powder will combine with the hydroxyl groups that have lost hydrogen atoms in the composite modifier to form Si-O-Ca bonds, thereby firmly adsorbing the composite modifier on the surface of the composite powder, improving the fluidity, dispersibility, and compatibility of the composite powder with the composite material, and further improving the mechanical properties of the plastic product.

[0056] In the present invention, the silane coupling agent preferably includes one or more of γ-methacryloxypropyltrimethoxysilane, n-octyltriethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane. More preferably, it includes one or more of γ-methacryloxypropyltrimethoxysilane and n-octyltriethoxysilane. The n-octyltriethoxysilane is purchased from Hubei Xinmingtai Chemical Co., Ltd., with the model GR-SI351, and the γ-(2,3-epoxypropoxy)propyltrimethoxysilane is purchased from Dow Corning, with the model Z-6011.

[0057] When the silane coupling agent includes multiple ones of γ-methacryloxypropyltrimethoxysilane, n-octyltriethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, the present invention does not make special limitations on the mass ratio between the silane coupling agents. The mass of the silane coupling agent is preferably 5 to 7‰ of the mass of the acicular wollastonite powder, and more preferably 5.5 to 6.5‰.

[0058] In the present invention, the surfactant preferably includes one or more of higher fatty alcohol polyoxyethylene ether, quaternary ammonium salt, and polyethylene glycol. More preferably, it includes higher fatty alcohol polyoxyethylene ether. When the surfactant includes multiple ones of higher fatty alcohol polyoxyethylene ether, quaternary ammonium salt, and polyethylene glycol, the present invention does not make special limitations on the mass ratio between the surfactants. The mass of the surfactant is preferably 2 to 4‰ of the mass of the acicular wollastonite powder, and more preferably 2.5 to 3.5‰.

[0059] In the present invention, the aluminate coupling agent preferably includes one or more of isopropyl distearoyl aluminate and isooctyl alcohol polyoxyethylene ether phosphate. More preferably, it includes isooctyl alcohol polyoxyethylene ether phosphate. The isopropyl distearoyl aluminate is preferably purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd., with the model GR-AL18, and the isooctyl alcohol polyoxyethylene ether phosphate is preferably purchased from Shandong Suihua Biotechnology Co., Ltd., with the model AEP(OEP-98).

[0060] When the aluminate coupling agent preferably includes isopropyl distearoyl aluminate and isooctyl polyoxyethylene ether phosphate, the present invention does not specifically limit the mass ratio between the aluminate coupling agents; the mass of the aluminate coupling agent is preferably 3 to 5‰ of the mass of the acicular wollastonite powder, and more preferably 3.5 to 4.5‰.

[0061] In the present invention, the temperature of the surface modification is preferably 40 to 80°C, more preferably 50 to 60°C, the time is preferably 30 to 50 min, and more preferably 45 to 50 min.

[0062] The present invention provides an inorganic non-metallic composite powder prepared by the above preparation method.

[0063] In the present invention, a layer of calcium silicate nanoparticles and a composite modifier are coated on the surface of the acicular wollastonite powder to obtain the inorganic non-metallic composite powder. The particle size of the acicular wollastonite powder is preferably 2.0 to 3.0 μm, and the particle size of the calcium silicate nanoparticles is preferably 60 to 80 nm, more preferably 65 to 75 nm.

[0064] In the present invention, the mass ratio of the acicular wollastonite powder to the calcium silicate nanoparticles is preferably 1:0.5 to 0.8, and more preferably 1:0.6 to 0.7.

[0065] The present invention provides the application of the above inorganic non-metallic composite powder in PA6 composite materials.

[0066] The following combines examples to detail the technical solutions provided by the present invention, but they cannot be understood as limiting the protection scope of the present invention.

[0067] The n-octyltriethoxysilane used in Examples 1 to 3 of the present invention was purchased from Hubei Xinmingtai Chemical Co., Ltd., and the model was GR-SI351;

[0068] The isooctyl polyoxyethylene ether phosphate used was purchased from Shandong Suihua Biotechnology Co., Ltd., and the model was AEP (OEP-98).

[0069] Example 1

[0070] The wollastonite raw ore with a silica content of 50.25 wt% was washed and then put into a jaw crusher and a hammer crusher, and was first crushed into wollastonite coarse particles with a diameter of 8 cm, and then secondarily crushed into wollastonite fine particles of 12 mm. Then it was transported to a 2.2 m * 7.2 m all-ceramic-lined ball mill for dry grinding. The grinding medium was alumina ceramic grinding balls, and the rotation speed was 500 r / min. After dry grinding for 20 min, acicular wollastonite powder with a particle size of 400 mesh was obtained;

[0071] 10 tons of acicular wollastonite powder is mixed with water to form a 40 wt% slurry, and sodium polyacrylate dispersant accounting for 2‰ of the mass of the acicular wollastonite powder, sodium pyrophosphate dispersant accounting for 2‰ of the mass of the acicular wollastonite powder, and sodium metaphosphate dispersant accounting for 3‰ of the mass of the acicular wollastonite powder are added. Then it is pumped into a 3600L vertical stirring ball mill, and ethylene glycol grinding aid accounting for 2‰ of the mass of the acicular wollastonite powder, polymeric polyol grinding aid accounting for 2‰ of the mass of the acicular wollastonite powder, and polymeric alkanolamine grinding aid accounting for 2‰ of the mass of the acicular wollastonite powder are added. Ensure that the slurry temperature is between 78 and 82 °C, and wet grinding is carried out at a rotational speed of 2500 r / min for 1.8 h to obtain wollastonite slurry with a particle size of 6000 mesh;

[0072] The wollastonite slurry is transferred to a slurry storage tank, stirred at a speed of 250 r / min for 1.5 h, and the pH of the wollastonite slurry is controlled at 12. Under stirring conditions, sodium silicate solution (mass concentration of 36%) and calcium hydroxide are added. The mass of the sodium silicate solution is 38% of the mass of the acicular wollastonite powder, and the mass ratio of the sodium silicate solution to the mass of calcium hydroxide is 2.7:1 for liquid-phase deposition coating to obtain a composite slurry;

[0073] The composite slurry is pumped into a flash dryer, and flash drying is carried out with clean hot air. The inlet air temperature of the hot air is 260 °C for 15 min. The dried powder enters a depolymerization and dispersion machine through a screw feeder for depolymerization and dispersion, and is collected by a cloth bag to obtain a composite powder with a particle size of 2.0 - 3.0 μm;

[0074] The composite powder is transported to a surface modifier, and γ-methacryloxypropyltrimethoxysilane accounting for 2‰ of the mass of the composite powder, n-octyltriethoxysilane accounting for 3‰ of the mass of the composite powder, higher fatty alcohol polyoxyethylene ether accounting for 3‰ of the mass of the composite powder, and isooctyl alcohol polyoxyethylene ether phosphate accounting for 3‰ of the mass of the composite powder are added. Surface modification is carried out at 60 °C for 45 min to obtain an inorganic non-metallic composite powder, where the particle size of calcium silicate nanoparticles is 65 nm, and the mass ratio of acicular wollastonite powder to calcium silicate nanoparticles is 1:0.6.

[0075] Example 2

[0076] The wollastonite raw ore with a silica content of 50.13 wt% is washed and then put into a jaw crusher and a hammer crusher for primary crushing into wollastonite coarse particles with a diameter of 10 cm, and then secondary crushed into wollastonite fine particles of 11 mm, and then transported to a 2.2 m * 7.2 m all-ceramic lined ball mill for dry grinding. The grinding medium is alumina ceramic grinding balls, and the rotational speed is 500 r / min for dry grinding. After 25 min of grinding, acicular wollastonite powder with a particle size of 400 mesh is obtained;

[0077] Mix 10 tons of acicular wollastonite powder with water to form a 45 wt% slurry. Add sodium polyacrylate dispersant at 3‰ of the mass of the acicular wollastonite powder, sodium pyrophosphate dispersant at 2‰ of the mass of the acicular wollastonite powder, and sodium metaphosphate dispersant at 3‰ of the mass of the acicular wollastonite powder. Pump it into a 3600L vertical stirring ball mill, and add ethylene glycol grinding aid at 3‰ of the mass of the acicular wollastonite powder, polymeric polyol grinding aid at 2‰ of the mass of the acicular wollastonite powder, and polymeric alkanolamine grinding aid at 2‰ of the mass of the acicular wollastonite powder. Ensure that the slurry temperature is between 78 and 82 °C, and carry out wet grinding at a rotational speed of 2500 r / min for 2 h to obtain wollastonite slurry with a particle size of 6000 mesh.

[0078] Transfer the wollastonite slurry to a slurry storage tank, stir at a speed of 250 r / min for 1.5 h, control the pH of the wollastonite slurry to 12, and under stirring conditions, add sodium silicate solution (mass concentration of 37%) and calcium hydroxide. The mass of the sodium silicate solution is 40% of the mass of the acicular wollastonite powder, and the mass ratio of the sodium silicate solution to the mass of calcium hydroxide is 2.8:1 to carry out liquid-phase deposition coating to obtain a composite slurry.

[0079] Pump the composite slurry into a flash dryer, and carry out flash drying with clean hot air. The inlet air temperature of the hot air is 270 °C for 12 min. Feed the dried powder into a depolymerization and dispersion machine through a spiral auger feeder for depolymerization and dispersion, and collect it through a cloth bag to obtain a composite powder with a particle size of 2.0 - 3.0 μm.

[0080] Transport the composite powder to a surface modifier, add γ-methacryloxypropyltrimethoxysilane at 3‰ of the mass of the composite powder, n-octyltriethoxysilane at 3‰ of the mass of the composite powder, higher fatty alcohol polyoxyethylene ether at 2‰ of the mass of the composite powder, and isooctyl polyoxyethylene ether phosphate at 4‰ of the mass of the composite powder, and carry out surface modification at 60 °C for 45 min to obtain an inorganic non-metallic composite powder, where the particle size of calcium silicate nanoparticles is 70 nm, and the mass ratio of acicular wollastonite powder to calcium silicate nanoparticles is 1:0.7.

[0081] Example 3

[0082] After washing the wollastonite raw ore with a silica content of 50.18 wt%, put it into a jaw crusher and a hammer crusher, and crush it into wollastonite coarse particles with a diameter of 10 cm for the first time, and then crush it into wollastonite fine particles of 10 mm for the second time. Then transport it to a fully ceramic-lined ball mill of 2.2 m * 7.2 m for dry grinding. The grinding medium is alumina ceramic grinding balls, and the rotational speed is 500 r / min for dry grinding. After grinding for 30 min, obtain acicular wollastonite powder with a particle size of 400 mesh.

[0083] Mix 10 tons of acicular wollastonite powder with water to form a 50 wt% slurry, add a sodium polyacrylate dispersant accounting for 2‰ of the mass of the acicular wollastonite powder, a sodium pyrophosphate dispersant accounting for 4‰ of the mass of the acicular wollastonite powder, and a sodium metaphosphate dispersant accounting for 3‰ of the mass of the acicular wollastonite powder. Pump it into a 3600L vertical stirring ball mill, add an ethylene glycol grinding aid accounting for 3‰ of the mass of the acicular wollastonite powder, a polymeric polyol grinding aid accounting for 3‰ of the mass of the acicular wollastonite powder, and a polymeric alkanolamine grinding aid accounting for 2‰ of the mass of the acicular wollastonite powder. Ensure that the slurry temperature is between 78 and 82°C, and carry out wet grinding at a rotational speed of 2500 r / min for 2.2 h to obtain a wollastonite slurry with a particle size of 6000 mesh.

[0084] Transfer the wollastonite slurry into a slurry storage tank, stir at a speed of 250 r / min for 1.5 h, control the pH of the wollastonite slurry to 12, and under stirring conditions, add a sodium silicate solution (mass concentration of 38%) and calcium hydroxide. The mass of the sodium silicate solution is 42% of the mass of the acicular wollastonite powder, and the mass ratio of the sodium silicate solution to calcium hydroxide is 2.9:1 to carry out liquid-phase deposition coating to obtain a composite slurry.

[0085] Pump the composite slurry into a flash dryer, and carry out flash drying with clean hot air. The inlet air temperature of the hot air is 280°C for 10 min. Feed the dried powder into a depolymerization and dispersion machine through a screw feeder for depolymerization and dispersion, and collect it through a cloth bag to obtain a composite powder with a particle size of 2.0 - 3.0 μm.

[0086] Transport the composite powder to a surface modifier, add γ-methacryloxypropyltrimethoxysilane accounting for 4‰ of the mass of the composite powder, n-octyltriethoxysilane accounting for 3‰ of the mass of the composite powder, a higher fatty alcohol polyoxyethylene ether accounting for 3‰ of the mass of the composite powder, and isooctyl polyoxyethylene ether phosphate accounting for 3‰ of the mass of the composite powder, and carry out surface modification at 60°C for 45 min to obtain an inorganic non-metallic composite powder, where the particle size of calcium silicate nanoparticles is 75 nm, and the mass ratio of acicular wollastonite powder to calcium silicate nanoparticles is 1:0.8.

[0087] Characterization and performance testing

[0088] 1. According to JC / T535 - 2007, conduct relevant index detection on the inorganic non-metallic composite powders prepared in Examples 1 - 3, and the results are shown in Table 1.

[0089] Table 1 Index detection results of the inorganic non-metallic composite powders obtained in Examples 1 - 3

[0090]

[0091]

[0092] As can be seen from Table 1, when comparing the inorganic non-metallic composite powders prepared in Examples 1 to 3, the larger the addition amounts of the composite grinding aid and the composite dispersant, the finer the particle size and the larger the specific surface area of the composite powder; the larger the addition amount of the composite modifier, the lower the oil absorption of the composite powder.

[0093] 2. (1) Respectively fill the inorganic non-metallic composite powders of Examples 1 to 3 into PA6 composites according to the following preparation method to obtain Samples 1 to 3;

[0094] Preparation method:

[0095] Put 60 parts of PA6, 5 parts of polyethylene wax, 1.5 parts of paraffin wax, and 30 parts of the inorganic non-metallic composite powder prepared in Examples 1 to 3 into a high-speed stirring mixer and mix and stir for 1 min to obtain a mixed material;

[0096] Use a co-rotating twin-screw extruder to granulate the obtained mixed material. The temperatures of each zone of the extruder are: 220 - 250 °C, the given rotational speed of the main machine: 310 r / min; the feeding rotational speed: 350 r / min; the material temperature: 230 °C; the head pressure: 0.8 MPa; the pelletizing rotational speed: 100 r / min;

[0097] After mixing and extrusion granulation, injection molding is carried out on an injection molding machine. The temperature of the injection molding machine is set to 250 °C, the injection pressure is 4 MPa, the holding pressure time is 4 s, the cooling time is 1 s, and the hydraulic oil temperature is 25 °C.

[0098] (2) Additionally provide Comparative Sample 1.

[0099] The difference between the preparation process of Comparative Sample 1 and Samples 1 to 3 is only that:

[0100] PA6 is 90 parts;

[0101] Do not add the inorganic non-metallic composite powder prepared in Examples 1 to 3;

[0102] Obtain Comparative Sample 1.

[0103] (3) Respectively measure the mechanical properties and glossiness of the obtained Samples 1 to 3 and Comparative Sample 1 according to the following measurement method, and the results are shown in Table 2.

[0104] Measurement method:

[0105] Use a universal testing machine to measure the tensile strength of the sample according to the GB / T1040 - 92 standard. The size of the test specimen is 150 mm × 20 mm × 4 mm, and the tensile speed is 5 mm / min;

[0106] Measure the flexural strength and flexural modulus of the sample according to the GB / T9341 - 2000 standard. The size of the test specimen is 80 mm × 10 mm × 4 mm, and the test speed is 2 mm / min;

[0107] The notched impact strength of the sample was tested using an electronic simply supported beam impact testing machine in accordance with the GB / T 1043-93 standard. The dimensions of the specimen were 80 mm × 10 mm × 4 mm, and the V-notch dimensions were (2 ± 0.1) mm × 4 mm.

[0108] The gloss of the sample was tested using a glossmeter at a measurement angle of 60° in accordance with the GB / T 13891 standard. The dimensions of the specimen were 80 mm × 10 mm × 4 mm.

[0109] Table 2 Mechanical properties and gloss data of Samples 1-3 and Comparative Sample 1

[0110]

[0111] As can be seen from Table 2, compared with the pure PA6 composite material without the inorganic non-metallic composite powder of the present invention, the inorganic non-metallic composite powder prepared by the present invention can improve the comprehensive mechanical properties and gloss of the composite material when used in the PA6 composite material.

[0112] As can be seen from the above examples, the present invention provides an inorganic non-metallic composite material with fine particle size, large specific surface area and low oil absorption, which has excellent filling performance and processing performance. When used in the PA6 composite material, it can improve the mechanical properties and gloss of the material.

[0113] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an inorganic non-metallic composite powder, characterized in that, It includes the following steps: Crush wollastonite ore through primary crushing, secondary crushing and dry grinding to obtain acicular wollastonite powder; Mix the acicular wollastonite powder, water, composite dispersant and composite grinding aid, and perform wet grinding to obtain wollastonite slurry; Under stirring conditions, mix the wollastonite slurry, sodium silicate solution and calcium hydroxide, and perform liquid-phase deposition coating to obtain composite slurry; Flash dry and depolymerize and disperse the composite slurry in sequence to obtain composite powder; Mix the composite powder with a composite modifier and perform surface modification to obtain inorganic non-metallic composite powder.

2. The preparation method according to claim 1, wherein The wollastonite ore contains ≥50wt% of silicon dioxide; the rotation speed of the dry grinding is 450 - 550r / min, the time is 15 - 35min; the particle size of the acicular wollastonite powder is 400 - 500 mesh.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the acicular wollastonite powder to water is 40 - 55:45 - 60; The composite dispersant includes one or more of sodium lignosulfonate, sodium polyacrylate, polyvinyl alcohol, sodium pyrophosphate and sodium metaphosphate, and the mass of the composite dispersant is 6 - 10‰ of the mass of the acicular wollastonite powder; The composite grinding aid includes one or more of polyhydric alcohol polymers, polyhydric alcohol amines, triethanolamine, ethylene glycol and diethylene glycol, and the mass of the composite grinding aid is 5 - 9‰ of the mass of the acicular wollastonite powder.

4. The preparation method according to claim 1, characterized in that, The rotation speed of the wet grinding is 2500 - 2800r / min, the time is 1.5 - 2.5h, and the temperature is 75 - 85℃; the solid content of the wollastonite slurry is 40 - 55wt%, and the particle size of the materials in the wollastonite slurry is 6000 mesh.

5. The preparation method according to claim 1, characterized in that, The mass concentration of the sodium silicate solution is 35 - 40%, the mass ratio of the acicular wollastonite powder to the mass of the sodium silicate solution is 100:35 - 45, and the mass ratio of the mass of the sodium silicate solution to the mass of calcium hydroxide is 2.6 - 3.0:1; During the liquid-phase deposition coating, the pH of the wollastonite slurry is 10 - 12, the temperature of the liquid-phase deposition coating is 25℃; the rotation speed of the stirring is 250 - 350r / min, and the time >1h.

6. The preparation method according to claim 1, wherein In the flash drying, the inlet air temperature of the hot air is 250 - 300℃, and the time is 8 - 15min; the particle size of the composite powder obtained after depolymerization and dispersion is 2.0 - 3.0μm.

7. The preparation method according to claim 1, characterized in that, The composite modifier includes silane coupling agent, surfactant and aluminate coupling agent, and the mass of the composite modifier is 10 - 15‰ of the mass of the acicular wollastonite powder; the temperature of the surface modification is 40 - 80℃, and the time is 30 - 50min.

8. The preparation method according to claim 7, characterized in that, The silane coupling agent includes one or more of γ-methacryloxypropyltrimethoxysilane, n-octyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and the mass of the silane coupling agent is 5 - 7‰ of the mass of the acicular wollastonite powder; The surfactant includes one or more of higher fatty alcohol polyoxyethylene ether, quaternary ammonium salt and polyethylene glycol, and the mass of the surfactant is 2 - 4‰ of the mass of the acicular wollastonite powder; The aluminate coupling agent includes one or more of isopropyl distearoyl aluminate and isooctyl polyoxyethylene ether phosphate, and the mass of the aluminate coupling agent is 3-5‰ of the mass of the acicular wollastonite powder.

9. The inorganic non-metallic composite powder prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the inorganic non-metallic composite powder according to claim 9 in plastic products.

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