Preparation method and application of intercalation modified composite talcum powder

Abstract

The invention relates to the technical field of talc modification, in particular to a preparation method and application of intercalation modified composite talc powder, and the preparation method is characterized by comprising the following specific operation steps: 1) pretreating raw materials, and pickling muscovite powder with hydrochloric acid; drying the superfine talcum powder; 2) mixing: taking muscovite, adding absolute ethyl alcohol, stirring at a low speed, and wetting at normal temperature; (3) strong extrusion compounding: adding superfine talcum powder into white mica, heating and stirring at a high speed; 4) coating the surface, stirring at a low speed, cooling, adding a titanate coupling agent, keeping the temperature, stirring at a high speed, sampling, and carrying out suspension detection; and 5) cooling to obtain the intercalation modified composite talcum powder. The preparation method has the beneficial effects that the talcum powder is strongly coated on the surface of the mica, the toughening and nucleation advantages of the talcum powder are kept, and meanwhile, the diameter-thickness ratio of a sheet structure is extended, so that the specific functionality of the talcum powder achieves a combined amplification effect, the stability of a composite modified particle structure is kept, and the compatibility with resin can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of talc modification, and particularly to a preparation method and application of an intercalation-modified composite talc powder. Background Art

[0002] Inorganic mineral powders have a series of unique physical and chemical properties as plastic modifiers, such as high specific surface area, good thermal stability, and mechanical strength. Talc powder not only has excellent lubricity but also exhibits good heat resistance and electrical insulation. Due to the flaky structure and high aspect ratio of talc powder, it can significantly enhance the rigidity and hardness of materials. In addition, talc powder also has properties such as heat resistance, thermal stability, lubricity, and dispersibility. In PP engineering plastics, talc powder has the following properties: 1) Compared with talc powder with a delamination ratio of 4 - 5 and a delamination ratio of 2.5 - 3, the impact strength and flexural modulus of PP plastics are both increased by 3 - 5%. Therefore, the flaky structure of talc powder has an obvious effect on improving the properties of PP plastics. 2) The 2μm particles in talc powder play a major role in the toughness of plastics. 3) The 1μm particles in talc powder can act as an inorganic nucleating agent in PP and play a nucleating role.

[0003] Mica not only has quite good electrical insulation, heat resistance, and corrosion resistance, but also its light transmission performance exceeds that of other inorganic powders, and it also has the function of blocking infrared rays. Therefore, it has been widely used in greenhouse films. As an important inorganic mineral filler, mica powder plays an important role in various fields such as plastics by virtue of its excellent physical and chemical properties. Talc and sericite are widely distributed layered silicate minerals. Compared with other minerals with similar structures, they are usually crystallized finely and have good affinity with organic polymer materials. Therefore, they are often used as additives for plastic materials.

[0004] Before being used as plastic fillers, such minerals generally need to be ultra-finely pulverized and modified to increase their blendability and affinity with plastic materials. During the mechanical pulverization process, the minerals are easily agglomerated into secondary particles, making it difficult to achieve the expected particle size. Moreover, surface modification is also difficult to completely change the inherent hydrophilicity of the mineral surface. Therefore, the filling degree of natural minerals in plastic materials is very low, and after filling, it often leads to a decrease in the mechanical strength of plastic materials.

[0005] The Chinese invention patent with the application number 201410169429.3 discloses a talc, sericite and silicone oil intercalated composite material and its preparation method, which is a composite material formed by inserting polydimethylsiloxane between the crystal structure layers of minerals. The preparation method steps are as follows: 1) Activate and remove impurities from talc and sericite using inorganic acid and reducing agent; 2) Dehydrate and dry after acid activation; 3) Grind talc, sericite and silicone oil together to form an intercalated compound, and the obtained product is the talc, sericite and silicone oil intercalated composite material. The disadvantage of this scheme is that the blending and grinding belong to simple mixing. Compared with coupling agents, the molecular group bonds of silicone oil as a lubricant are not tightly connected. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of intercalation-modified composite talc powder. Mica with a peeling ratio of 10 - 12 is used as a carrier, and the talc powder is modified by utilizing the characteristics of being an inorganic powder with an obvious flaky structure, maintaining the advantages of toughness enhancement and nucleation of talc powder, and at the same time extending the aspect ratio of the flaky structure, so that the functional characteristics of talc powder are combined and amplified.

[0007] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0008] Technical solution one: A preparation method of intercalation-modified composite talc powder, characterized in that the specific operation steps are as follows: 1) Raw material pretreatment, wash muscovite powder with hydrochloric acid to remove impurities between layers. After pickling, wash with clear water until pH > 6.5, and dry to a moisture content < 0.5%; dry ultrafine talc powder to a moisture content < 0.5%; 2) Mixing, add anhydrous ethanol to the pickled muscovite powder and perform low-speed stirring in a high-speed mixer, and wet at room temperature for at least 20 minutes; 3) Strong extrusion and compounding, add the wet muscovite powder obtained in step 2) to ultrafine talc powder, heat up to 160 - 165 °C, and stir at high speed for 30 - 60 minutes; 4) Surface coating, stir at low speed and gradually cool down to between 110 - 120 °C, add titanate coupling agent, maintain the temperature, and then stir at high speed for 15 - 30 minutes, and take samples for suspension detection; 5) Cooling and temperature reduction, stir at low speed and naturally cool down to below 40 °C to obtain intercalation-modified composite talc powder.

[0009] Further, the muscovite powder is ground and classified from natural silicate minerals, with the molecular formula KAl2(Al2Si3O 10 )(OH,F)2, the peeling ratio is 10 - 12, the particle size is 2500 mesh, the whiteness is 94 - 96, with a flaky structure, and the true density is 2.7 - 2.9 g.c / m 3 , and the Mohs hardness is 1.

[0010] Further, the nominal maximum particle size of the ultrafine talc powder is d98 = 2.0 μm, d50 = 0.7 μm, with a flaky structure. The chemical formula of talc is Mg3[Si4O 10 (OH)2, the true density is 2.7 - 2.9 g / cm 3 , the Mohs hardness is 1 - 3, and the whiteness is 94 - 96.

[0011] Further, the concentration of the hydrochloric acid is 0.7 mol / L.

[0012] Further, in step 1), the pickling temperature is 80 - 90 °C and the pickling time is 1 - 3 hours.

[0013] Further, in step 1), the drying temperature is 105 - 120 °C.

[0014] Further, in step 3), the suspension rate of the suspension detection ≥ 70% is qualified.

[0015] Further, the speed range of the low-speed stirring is 100 - 150 revolutions per minute, and the speed range of the high-speed stirring is 1200 - 1500 revolutions per minute.

[0016] Further, the weight ratio of muscovite, ultrafine talc powder, absolute ethanol, and titanate coupling agent is: 10 - 30 parts of muscovite, 10 - 30 parts of ultrafine talc powder, 10 - 30 parts of absolute ethanol, and 1 - 2 parts of titanate coupling agent.

[0017] Technical solution two: An application of an intercalation-modified composite talc powder, characterized in that when producing PP plastic products, the weight ratio of each component is: 80 parts of polypropylene, 20 parts of modified composite talc powder, and 1 part of calcium stearate.

[0018] In the technical solution of the present invention, the working principle is that first, the surface of the talc powder is coated to modify the muscovite, and then the titanate coupling agent is coated to complete the intercalation modification of the muscovite. The titanate coupling agent is a chemical substance, mainly used to improve the interfacial interaction between inorganic fillers and organic polymers, thereby improving the performance and processability of the materials. Titanates have both coupling and other special properties; R'- is a long carbon chain alkyl group, which is relatively soft and can be bent and entangled with organic polymers, improving the compatibility between organic and inorganic substances and enhancing the impact strength of the materials; Y is a hydroxyl group, amino group, epoxy group, or group containing a double bond, etc. These groups are connected to the end of the titanate molecule and can react with organic substances to bind together. Applied in the plastic industry, it can activate the filler, thereby increasing the filling amount, reducing the resin usage, lowering the product cost, improving the processing performance, increasing the gloss of the product, and improving the quality.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1) Mica is used as the carrier. Taking advantage of the fact that mica and talc powder are both inorganic powders with obvious flaky structures, the talc powder is modified to maintain the toughening and nucleating advantages of the talc powder, while extending the aspect ratio of the flaky structure, so that the functional characteristics of the talc powder are combined and amplified.

[0021] 2) After the composite modification treatment, 2μm and 1μm talc powder particles enter the interlayer of mica with the help of a coupling agent to form an intercalation substitution modification. Larger-sized talc powder is coated on the surface of mica to form a surface coating modification. The coupling agent is coated as a whole, which not only maintains the stability of the composite modified particle structure but also enhances the compatibility with the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the electron microscope photograph of the mica raw material in the embodiment of the present invention;

[0023] Figure 2 is the electron microscope photograph of the talc powder raw material in the embodiment of the present invention;

[0024] Figure 3 is the electron microscope photograph of the intercalation modified composite talc powder obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other specific embodiments can also be obtained based on these specific embodiments.

[0027] Generally, the components of the embodiments of the present invention described and shown in the specific embodiments here can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention.

[0028] In the following embodiments, the mica powder used is ground and classified from natural silicate minerals, with the molecular formula of KAl2(Al2Si3O 10 )(OH,F)2, the delamination ratio is 10 - 12, the particle size is 2500 mesh, the whiteness is 94 - 96, with a flaky structure, and the true density is 2.7 - 2.9 g.c / m3 , the Mohs hardness is 1. The nominal maximum particle size of the ultrafine talc powder is d98 = 2.0 μm, d50 = 0.7 μm, and it has a flaky structure. The chemical formula of talc is Mg3[Si4O 10 (OH)2, and the true density is 2.7 - 2.9 g.c / m 3 , the Mohs hardness is 1 - 3, and the whiteness is 94 - 96. The concentration of hydrochloric acid is 0.7 mol / L. The ultrafine talc powder is dried at 105°C for 1.5 hours until the moisture content is <0.5%, and it is reserved for use. The muscovite powder is pickled with hydrochloric acid to remove the interlayer impurities. The pickling temperature is 80 - 90°C, and the pickling time is 1 - 3 hours. After pickling, it is washed with clear water until the pH > 6.5, and then dried until the moisture content is <0.5%, and it is reserved for use.

[0029] Example 1

[0030] A preparation method of intercalation-modified composite talc powder, and the specific operation steps are as follows:

[0031] 1) Pretreatment of raw materials: The muscovite powder is pickled to remove the interlayer impurities, washed with clear water and then dried; the ultrafine talc powder is dried;

[0032] 2) Primary mixing: Take 1000 g of pickled muscovite, add 2500 g of anhydrous ethanol, and carry out low-speed stirring at normal temperature for 20 minutes in a high-speed mixer. The speed range of the low-speed stirring is 150 revolutions per minute;

[0033] 3) Strong extrusion and compounding: Add 2000 g of ultrafine talc powder to the high-speed mixer, heat up to 160 - 165°C, and carry out high-speed stirring for 30 minutes. The fine talc powder first coats on the surface of the muscovite, and then is coated as a whole with a coupling agent to achieve intercalation modification. The speed range of the high-speed stirring is 1500 revolutions per minute;

[0034] 4) Surface coating: Carry out low-speed stirring and gradually cool down to between 110 - 120°C, add 150 parts of titanate coupling agent, and keep stirring at high speed for 15 minutes. The speed range of the high-speed stirring is 1200 revolutions per minute. Take a sample for suspension detection. When the suspension rate reaches more than 70%, the reaction ends;

[0035] 5) Low-speed stirring: Gradually cool down to below 40°C to obtain the intercalation-modified composite talc powder.

[0036] After the composite modification treatment, for the 2um and 1um talc powder particles, the coupling agent enters into the interlayers of the muscovite to form intercalation substitution modification, and the talc powder coats on the surface of the muscovite to form surface coating modification. The overall coating of the coupling agent not only maintains the stability of the structure of this composite modified particle, but also enhances the compatibility with the resin. The electron microscope photo of the obtained intercalation-modified composite talc powder is shown in Figure 3 .

[0037] Example 2

[0038] A preparation method of intercalated modified composite talc powder, the specific operation steps are as follows:

[0039] 1) Pretreatment of raw materials: The muscovite powder is pickled to remove the interlayer impurities, washed with clear water and then dried; the ultrafine talc powder is dried.

[0040] 2) Primary mixing: Take 1000 g of pickled muscovite, add 3000 g of anhydrous ethanol, and carry out low-speed stirring at normal temperature for 20 minutes in a high-speed mixer. The speed range of low-speed stirring is 150 revolutions per minute.

[0041] 3) Strong extrusion compounding: Add 2500 g of ultrafine talc powder to the high-speed mixer, heat up to 160 - 165 °C, and carry out high-speed stirring for 30 minutes. The fine talc powder is first coated on the surface of muscovite, and then coated with a coupling agent as a whole to achieve intercalation modification. The speed range of high-speed stirring is 1500 revolutions per minute.

[0042] 4) Surface coating: Carry out low-speed stirring and gradually cool down to between 110 - 120 °C, add 100 parts of titanate coupling agent, keep the temperature and carry out high-speed stirring for 15 minutes. The speed range of high-speed stirring is 1200 revolutions per minute. Take a sample for suspension detection. When the suspension rate reaches more than 70%, the reaction ends.

[0043] 5) Low-speed stirring: Gradually cool down to below 40 °C to obtain the intercalated modified composite talc powder.

[0044] Example 3

[0045] A preparation method of intercalated modified composite talc powder, the specific operation steps are as follows:

[0046] 1) Pretreatment of raw materials: The muscovite powder is pickled to remove the interlayer impurities, washed with clear water and then dried; the ultrafine talc powder is dried.

[0047] 2) Primary mixing: Take 1000 g of pickled muscovite, add 1000 g of anhydrous ethanol, and carry out low-speed stirring at normal temperature for 20 minutes in a high-speed mixer. The speed range of low-speed stirring is 150 revolutions per minute.

[0048] 3) Strong extrusion compounding: Add 1000 g of ultrafine talc powder to the high-speed mixer, heat up to 160 - 165 °C, and carry out high-speed stirring for 30 minutes. The fine talc powder is first coated on the surface of muscovite, and then coated with a coupling agent as a whole to achieve intercalation modification. The speed range of high-speed stirring is 1500 revolutions per minute.

[0049] 4) Surface coating: Stir at low speed and gradually cool down to between 110 - 120 °C. Add 200 parts of titanate coupling agent, and keep stirring at high speed for 15 minutes. The high-speed stirring speed ranges from 1200 revolutions per minute. Take samples for suspension detection. When the suspension rate reaches over 70%, the reaction ends.

[0050] 5) Stir at low speed and gradually cool down to below 40 °C to obtain the intercalation-modified composite talc powder.

[0051] The following are the performance verification experiments on the intercalation-modified composite talc powder obtained from Examples 1 - 3.

[0052] 1. Main raw materials

[0053] Polypropylene (PP), K7726H, from North Huajin Chemical Industry Co., Ltd.; Talc powder (Talc), SD - 9409, from Liaoning Xinda Talc Group; Muscovite powder, BF777, from Qingdao Xinfenghang Chemical Co., Ltd.; Titanate coupling agent, JL - 0025, from Nanjing Jinlaiwang Plastic Technology Co., Ltd.; Calcium stearate, BS - 3818, from Huamingtai Chemical Co., Ltd.

[0054] 2. Main equipment

[0055] Universal testing machine, UTM - 1423, from Chengde Jinjian Testing Instrument Co., Ltd.; Simply supported beam impact testing machine, XJJ - 5, from Chengde Jinjian Testing Instrument Co., Ltd.; Cantilever beam impact testing machine, XJU - 5.5, from Chengde Jinjian Testing Instrument Co., Ltd.; Twin-screw extruder, LNSD - 51, from Jiangsu Hongyunxiang Rubber and Plastic Machinery Co., Ltd.; Plastic injection molding machine, SA900II / 260, from Haitian Plastic Machinery Group Co., Ltd.; High-speed stirrer, GRN - 20, from Fuxin Xinke Machinery Manufacturing Co., Ltd.; Electrothermal blast drying oven, XCB - 300, from Chengde Jinjian Testing Instrument Co., Ltd.

[0056] 3. Test process and test method

[0057] Prepare PP plastic products by mixing the intercalation-modified composite talc powder, polypropylene, and calcium stearate obtained from Examples 1 - 3 in a ratio of 20:80:1. Use different specifications of talc powder, polypropylene, and calcium stearate applied in a ratio of 20:80:1 as the control group. Granulate and dry them respectively using a twin-screw extruder, and then use an injection molding machine and a mold for injection molding to obtain test specimens of standard size. The specimens are stored in a constant temperature and humidity chamber for 24 hours before testing. The injection molding process adopts a multi-stage injection molding control process. The main process parameters are: plasticizing temperature, 200 °C; screw speed, 50 r·min-1; injection pressure, 45%; injection time, 30% for the first stage, 50% for the middle stage, 30% for the last stage; holding pressure, 30%; holding time, 8 s; cooling time, 10 s.

[0058] Spline production standard: GBT17037.1-2019 Plastics - Preparation of specimens for injection moulding of thermoplastic materials - Part 1: General principles and preparation of multipurpose and bar specimens.

[0059] The test standards in the experiment are: GB / T1040-2006 Determination of tensile properties of plastics; GB / T1043.1-2008 Determination of Charpy impact properties; GB / T1843-2008 Determination of Izod impact strength; GB / T9341-2008 Determination of flexural properties of plastics.

[0060] Results and Discussion

[0061] The performance comparison data of the intercalation - modified composite talc powder obtained from Examples 1 - 3 of the present invention with fine talc powder and muscovite powder filled alone in modified polypropylene, as well as the performance data comparison of simple blend filling of talc powder and muscovite powder in polypropylene, are shown in Table 1.

[0062] Table 1

[0063]

[0064] It can be seen from Table 1 that the rigidity index, flexural modulus and tensile strength of the polypropylene specimens obtained from Examples 1 - 3 are generally 10 - 15% higher than those of Comparative Examples 1 - 3. The intercalation - modified composite talc powder product of the present invention can form a good barrier layer protection in marine heavy - duty anti - corrosion primers, effectively improving the salt - fog resistance and weather resistance of the coatings.

[0065] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing intercalated modified composite talc, characterized in that: The specific steps are as follows: 1) Raw material pretreatment: muscovite powder is pickled with hydrochloric acid to remove interlayer impurities. After pickling, it is washed with clean water until the pH value is greater than 6.5, and dried to a moisture content of less than 0.5%; ultrafine talc powder is dried to a moisture content of less than 0.5%; 2) Mixing: add anhydrous ethanol to the acid-washed muscovite powder, stir at a low speed in a high-speed mixer, and wet at room temperature for at least 20 minutes; 3) Strong extrusion compounding, adding the wetted muscovite powder obtained in step 2) to the ultrafine talc powder, heating to 160-165° C., and stirring at high speed for 30-60 minutes; 4) Surface coating, stirring at low speed and gradually cooling to between 110-120°C, adding titanate coupling agent, maintaining the temperature, stirring at high speed for 15-30 minutes, and taking samples for suspension detection; 5) Cooling and stirring at a low speed to naturally cool down to below 40° C. to obtain intercalated modified composite talc powder.

2. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The muscovite powder is obtained by grinding and grading natural silicate minerals, and its molecular formula is KAl2(Al2Si3O 10 )(OH,F)2, peeling ratio is 10-12, particle size is 2500 mesh, whiteness is 94-96, flaky structure, true density is 2.7-2.9gc / m 3 , Mohs hardness is 1.

3. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The nominal maximum particle size of the ultrafine talc powder is d98=2.0 μm, d50=0.7 μm, and the talc has a flaky structure. The molecular formula of talc is Mg3[Si4O 10 ](OH)2, true density 2.7-2.9gc / m 3 , Mohs hardness is 1-3, and whiteness is 94-96.

4. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The concentration of the hydrochloric acid is 0.7 mol / L.

5. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: In the step 1), the pickling temperature is 80-90° C. and the pickling time is 1-3 hours.

6. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The drying temperature in step 1) is 105-120°C.

7. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The suspension rate of the suspension test in step 3) is qualified if it is ≥ 70%.

8. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The speed range of the low-speed stirring is 100-150 rpm, and the speed range of the high-speed stirring is 1200-1500 rpm.

9. The method for preparing an intercalated modified composite talc according to claim 1, characterized in that: The weight proportions of the muscovite, ultrafine talc, anhydrous ethanol and titanate coupling agent are: 10-30 parts of muscovite, 10-30 parts of ultrafine talc, 10-30 parts of anhydrous ethanol and 1-2 parts of titanate coupling agent.

10. The use of any one of the intercalation-modified composite talc powders according to claims 1-9, characterized in that: When producing PP plastic products, the weight ratio of each component is: 80 parts of polypropylene, 20 parts of modified composite talc, and 1 part of calcium fatty acid.

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