A PP-based talcum powder masterbatch, its preparation method and application

Abstract

The present invention relates to a PP-based talc masterbatch and a preparation method and application thereof, and belongs to the technical field of development and application of talc masterbatch. The PP-based talc masterbatch provided by the present invention comprises the following components by mass: 15-25 parts of metallocene PP, 75-85 parts of talc co-modified by silane coupling agent and hydroxy silicone oil, 0.3-0.6 parts of antioxidant, 0.2-0.5 parts of lubricant, and 0.2-0.5 parts of PE wax. The PP-based talc masterbatch of the present invention can solve the problem that the PP-based talc masterbatch on the market is prone to yellowing and whiteness decreases in the process, improves the problem that the talc masterbatch has a greater impact on the impact strength of modified PP composites, satisfies the application of the PP-based talc masterbatch in some PP products with higher white quality requirements, and enables the PP products to maintain higher impact performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of the development and application of talcum powder masterbatch, and particularly relates to a PP-based talcum powder masterbatch, a preparation method thereof and an application thereof. Background Art

[0002] Talcum powder is often used in the processing industry of polypropylene (PP) modified plastics. The PP-based talcum powder masterbatch is a highly concentrated talcum powder masterbatch based on PP as a carrier. When applied in PP modification production, it can solve the problems of talcum powder bridging and uneven feeding caused by the direct addition method of talcum powder. In addition, it not only improves the production efficiency of PP modified plastics, but also facilitates packaging and transportation, and reduces the dust pollution in the production workshop.

[0003] The preparation method of PP-based talc masterbatch usually involves first using a Banbury mixer to mix fluffy talc, PP carrier, and additives into a rubber block premix, allowing the talc to be fully wetted and dispersed in the PP carrier. Then, the rubber block premix is fed into a single-screw extruder through a conical twin feeder, and extrusion granulation is carried out at a certain rotational speed and temperature to obtain the PP-based talc masterbatch. However, in industrial production, to improve production efficiency, large-sized Banbury mixers are usually configured. Large-sized Banbury mixers use pressure mixing to carry out intensive mixing of materials. Since talc is very fluffy and has a large bulk volume, simply heating through the bottom of the Banbury mixer tank cannot efficiently heat up the materials. It is necessary to use a pressure cover to compact and mix the materials to achieve material heating and plasticization. The PP carrier is frictionally sheared during the compaction and mixing process and is prone to thermal oxidation under high-pressure heating. Coupled with the fact that pressure mixing cannot exhaust gas in a timely manner, the entire kettle of materials turns yellow. This results in poor color quality of the prepared talc masterbatch, a significant decrease in whiteness, and limits the application of talc masterbatch in products with high whiteness quality. To improve the quality problem of easy yellowing during the preparation of PP-based talc masterbatch, some technical solutions shorten the mixing time during the production of PP-based talc masterbatch, and stop mixing before the materials are fully plasticized. This preparation method controls the degree of material plasticization through the mixing time, but the effect is not satisfactory. The materials are not fully mixed and plasticized, resulting in uneven feeding and unstable production during extrusion granulation. The prepared talc masterbatch has a high crushing rate and an uneven appearance. In addition, after talc and talc masterbatch modify PP materials, while the rigidity is improved, the impact performance of the materials also drops significantly. Especially after adding talc to high-impact PP, the impact strength often drops from a relatively high value to a relatively low value. In the industry, to address this problem, a third-component toughening agent is usually added to the talc-modified PP composite for toughening modification. However, the toughening agent is expensive and has a significant impact on the rigidity of the talc-modified PP composite. Patent CN113861554A discloses a high-gloss, well-dispersed polypropylene talc masterbatch and its preparation method, using homopolymer low-melt-index polypropylene and metallocene low-isotactic polypropylene as carriers. However, the melt index of metallocene low-isotactic polypropylene (the melt index is 2000 - 2500 g / 10min) is too high, and the whiteness of the PP carrier talc masterbatch prepared by pressure mixing is not guaranteed, and the impact strength of the talc masterbatch on PP is not considered.

[0004] Therefore, it is of great significance to develop a PP-based talc masterbatch with high whiteness and excellent impact resistance for PP modified materials. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art, and provide a PP-based talc masterbatch, its preparation method, and its application.

[0006] The present invention is realized through the following technical solutions:

[0007] In a first aspect, the present invention provides a PP-based talc masterbatch, comprising the following components, by weight: 15-25 parts of metallocene PP, 75-85 parts of talc co-modified with a silane coupling agent and hydroxy silicone oil, 0.3-0.6 parts of an antioxidant, 0.2-0.5 parts of a lubricant, and 0.2-0.5 parts of PE wax.

[0008] The PP-based talc masterbatch provided by the present invention can solve the problem that the PP-based talc masterbatch currently on the market is prone to yellowing and whiteness reduction during the production process, improve the problem that the talc masterbatch has a significant impact on the impact strength of the modified PP composite material, meet the application of the PP-based talc masterbatch in some PP products with high white quality requirements, and enable the PP products to maintain high impact performance.

[0009] The PP-based talc masterbatch of the present invention uses metallocene PP as a carrier. The metallocene PP has a narrow molecular weight distribution, a low melting point, good processability, high impact resistance, both softness and heat resistance, and high thermal stability. With the metallocene PP as a carrier, antioxidants and lubricants are added, and banburying can be performed at a lower temperature, significantly delaying and improving the yellowing tendency of the material, and preparing a PP-based talc masterbatch with high whiteness and high talc content.

[0010] The present invention further performs co-grafting modification of the preferred talc with a silane coupling agent and hydroxy silicone oil. The silanol groups on the surface of the silane coupling agent can undergo a condensation reaction with the hydroxy groups on the surface of the talc or combine with the original siloxane hydroxy groups on the surface, thereby removing moisture from the surface of the talc and forming siloxane bonds with the oxygen atoms therein, thereby significantly improving the affinity between the talc and PP. The specific chemical grafting process is achieved through the following two steps: first, the silane coupling agent is hydrolyzed to form silanol, which then condenses with the hydroxyl group on the surface of talc for grafting; for example, the ethoxy group (-OCH2CH3) of KH550 is hydrolyzed under heating conditions to form silanol (-Si-OH), NH2(CH2)3Si(OCH2CH3)3+3H2O→NH2(CH2)3Si(OH)3 (γ-aminopropyltrihydroxysilane)+3CH3CH2OH, and the hydrolyzed silanol (-Si-OH) then condenses with the hydroxyl group (-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds, and removes water molecules: NH2(CH2)3Si(OH)3+HO–[talc surface]→NH2(CH2)3Si-O-[talc surface]+H2O.

[0011] The hydroxyl groups on the surface of hydroxy silicone oil and talcum powder can also undergo similar chemical reactions. The terminal hydroxyl groups of hydroxy silicone oil and the hydroxyl groups on the surface of talcum powder undergo a condensation reaction under heating conditions to form silicon-oxygen bonds, grafting the non-polar siloxane structure onto the surface of talcum powder to form activated talcum powder, improving the dispersibility and wettability of talcum powder in the PP matrix. In addition, the siloxane structure has a compatibilizing and lubricating toughening effect, which can improve the problem that talcum powder has a greater impact on the impact performance of PP. The specific chemical grafting process is as follows:

[0012] Talcum powder (Mg3Si4O 10 (OH)2) has silanol groups (-Si-OH) and magnesium hydroxide groups (-Mg-OH) on its surface, and these hydroxyl groups are the active sites for the reaction. The terminal hydroxyl groups of hydroxy silicone oil and the hydroxyl groups (-Si-OH or -Mg-OH) on the surface of talcum powder undergo dehydration condensation to form Si-O-Si or Si-O-Mg covalent bonds and release water molecules. Through -Si-OH (talcum powder) + HO-[Si(CH3)2O] n -H → -Si-O-[Si(CH3)2O] n -O-Si- + H2O, or -Mg-OH (talcum powder) + HO-[Si(CH3)2O] n -H → -Mg-O-[Si(CH3)2O] n -O-Mg- + H2O reaction.

[0013] In the present invention, through the synergistic compatibilizing effect of silane coupling agent and hydroxy silicone oil, surface graft modification is carried out on talcum powder, significantly improving the dispersibility and interfacial compatibility of talcum powder in PP, accelerating infiltration and dispersion in the PP carrier, shortening the mixing time, indirectly improving the yellowing effect of the material, and also improving the impact strength retention rate of talcum powder in the modified PP composite.

[0014] Preferably, the melting point of the metallocene PP is 150°C - 160°C, and the melt index is 20 g / 10 min - 100 g / 10 min.

[0015] Specifically, the melting point of the metallocene PP in the present invention is obtained by testing using the DSC method, and the melt index is obtained by testing under the conditions of 230°C / 2.16 kg in accordance with GB / T3682.1 - 2018.

[0016] The present invention preferably uses metallocene PP with a melting point range of 150°C - 160°C to prepare talcum powder masterbatch, which can reduce the mixing and plasticizing temperature, reduce the yellowing of talcum powder masterbatch caused by too high temperature. Metallocene PP has good impact resistance, a narrower molecular weight distribution than ordinary PP, and higher thermal stability. With the antioxidant system, it has high thermal stability during the manufacturing process and has a very small tendency to turn yellow. And because of its low processing temperature, it can give the PP-based talcum powder masterbatch a wider processing temperature window, making the mixing and dispersion effect of the material better.

[0017] Preferably, the silane coupling agent and hydroxyl silicone oil co-modified talc powder are obtained by mixing and reacting talc powder, silane coupling agent and hydroxyl silicone oil; the addition amount of the silane coupling agent is 0.5%-1% of the mass of the talc powder; the addition amount of the hydroxyl silicone oil is 0.3%-1% of the mass of the talc powder.

[0018] Preferably, the particle size D90 of the talc powder is 8μm-15μm (which can be tested by a laser particle size analyzer), the whiteness ≥90 (tested by a whiteness meter according to GB / T 5950-2008), the silicon dioxide content ≥59% (tested by the chemical analysis method of talc powder according to GB / T15343-2020), and the calcium oxide content ≤4% (tested by the chemical analysis method of talc powder according to GB / T15343-2020).

[0019] Since the higher the test value of the whiteness of the talc powder is as it is ground finer, the present invention finds that talc powder with a particle size within the above range and a whiteness ≥90, and the silicon dioxide and calcium oxide contents within the above range can endow the PP-based talc masterbatch of the present invention with higher performance and whiteness.

[0020] Preferably, the silane coupling agent includes an amino silane coupling agent.

[0021] In a specific embodiment of the present invention, the silane coupling agent can be γ-aminopropyltriethoxysilane (KH550).

[0022] Preferably, the hydroxyl silicone oil includes a dihydroxy-terminated siloxane.

[0023] Preferably, the hydroxyl silicone oil includes at least one of a low-viscosity hydroxyl silicone oil and a medium-high-viscosity hydroxyl silicone oil; the viscosity of the low-viscosity hydroxyl silicone oil is 25-100mPa·s, and the viscosity of the medium-high-viscosity hydroxyl silicone oil is 750-3000mPa·s.

[0024] More preferably, the hydroxyl silicone oil includes a low-viscosity hydroxyl silicone oil and a medium-high-viscosity hydroxyl silicone oil, and the mass ratio of the low-viscosity hydroxyl silicone oil to the medium-high-viscosity hydroxyl silicone oil is (0.3-0.5):(0.3-0.5).

[0025] Specifically, the silane coupling agent and hydroxyl silicone oil co-modified talc powder are obtained by mixing and reacting talc powder, silane coupling agent, low-viscosity hydroxyl silicone oil and medium-high-viscosity hydroxyl silicone oil; the addition amount of the silane coupling agent is 0.5%-1% of the mass of the talc powder; the addition amount of the low-viscosity hydroxyl silicone oil is 0.3%-5% of the mass of the talc powder; the addition amount of the medium-high-viscosity hydroxyl silicone oil is 0.3%-5% of the mass of the talc powder.

[0026] The research of the present invention finds that the compounding of low-viscosity hydroxy silicone oil and medium-high-viscosity hydroxy silicone oil can further improve the effect of the material. The low-viscosity hydroxy silicone oil has a low molecular weight, short chain segments, and high reaction activity, but the coating effect on talcum powder is not as good as that of medium-high-viscosity hydroxy silicone oil. For medium-high-viscosity hydroxy silicone oil, the siloxane chain segments are longer, the reaction activity is lower than that of low-viscosity hydroxy silicone oil, but it has better flexibility and a better coating effect on talcum powder. Grafting it onto talcum powder can significantly improve the problem that talcum powder has a greater impact on the impact performance of modified PP composites, and the impact strength retention rate is relatively high when applied to modified PP composites.

[0027] Preferably, the silane coupling agent and hydroxy silicone oil are preheated and then mixed and reacted with the talcum powder; preheating can improve the reaction activity and the effect of graft-modified talcum powder is more significant.

[0028] Preferably, the antioxidant includes at least one of thioester antioxidants, hindered phenol antioxidants, and phosphite antioxidants.

[0029] More preferably, the antioxidant includes 40%-60% of thioester antioxidants, 10%-30% of hindered phenol antioxidants, and 20%-40% of phosphite antioxidants by mass percentage.

[0030] The compounding of thioester antioxidants, hindered phenol antioxidants, and phosphite antioxidants can give full play to the synergistic effect among the three, greatly improve the antioxidant efficiency, and significantly improve the yellowing resistance of PP-based talcum powder masterbatch.

[0031] In a specific embodiment of the present invention, the antioxidant includes 50% of thioester antioxidants, 20% of hindered phenol antioxidants, and 30% of phosphite antioxidants by mass percentage.

[0032] Preferably, the lubricant includes stearate; specifically, the stearate includes at least one of calcium stearate, zinc stearate, and magnesium stearate.

[0033] Preferably, the molecular weight of the PE wax is 1000-3000.

[0034] In a second aspect, the present invention provides a method for preparing the PP-based talcum powder masterbatch, including the following steps:

[0035] (1) Mix metallocene PP, antioxidant, lubricant, and PE wax evenly according to the said mass parts to obtain a mixture;

[0036] (2) First add the co-modified talcum powder of silane coupling agent and hydroxy silicone oil into a kneader, and then add the mixture obtained in step (1), and knead to obtain a pre-mixed rubber block;

[0037] (3) Extrude and pelletize the obtained rubber block premix in step (2) to obtain the PP-based talcum powder masterbatch.

[0038] The preparation method of the PP-based talcum powder masterbatch of the present invention is simple and applicable to industrial production.

[0039] Preferably, in the step (3), the process settings of the single-screw extruder are as follows: the feeding section, zone 1: 150 °C - 160 °C, zone 2: 165 °C - 170 °C, zone 3: 165 °C - 170 °C, zone 4: 165 °C - 170 °C, zone 5: 165 °C - 170 °C, zone 6 (die head): 170 °C - 180 °C, and the rotation speed of the extruder is 30 - 50 revolutions per minute.

[0040] Thirdly, the present invention provides the application of the PP-based talcum powder masterbatch in the preparation of household appliances, automobiles, electronic and electrical appliances.

[0041] When the PP-based talcum powder masterbatch of the present invention is applied to PP, it can endow PP products with high whiteness and high impact strength, has a broad application scenario, and can be applied to fields such as household appliances, automobiles, electronic and electrical appliances, etc.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. High whiteness: The high-performance PP-based talcum powder masterbatch of the present invention adopts the surface graft modification technology of talcum powder, and through graft modification, active talcum powder is made. It can be quickly plasticized and dispersed in the carrier during internal mixing, shortening the plasticizing processing time of the material and reducing the possibility of yellowing. In addition, metallocene PP with a low processing temperature is used as the carrier, which has a narrow molecular weight distribution and high thermal stability, and can provide a relatively wide temperature processing window. After compounding with an efficient antioxidant system, the tendency of yellowing during the internal mixing process is extremely small. Therefore, the PP-based talcum powder masterbatch prepared by the technical solution of the present invention has high whiteness, which is basically equivalent to the whiteness of the PP composite prepared by the original method of adding talcum powder powder.

[0044] 2. High performance: The high-performance PP-based talcum powder masterbatch of the present invention uses silane coupling agent and hydroxyl silicone oil to graft-modify talcum powder, making talcum powder into active talcum powder. It is not only easy to infiltrate and disperse in PP, but also enhances the interfacial properties with the PP substrate, improves the ability to resist impact damage at the interface with PP, plays a role in compatibilization and lubricating toughening. The prepared PP-based talcum powder masterbatch not only has a significant effect on increasing the rigidity of PP, but also significantly improves the problem that talcum powder has a greater impact on the impact strength of PP, and improves the impact strength retention rate of the PP composite. Specific Embodiments

[0045] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0047] Examples 1-6

[0048] The composition of the PP-based talcum powder masterbatch described in the embodiments of the present invention is shown in Table 1.

[0049] The preparation method of the PP-based talcum powder masterbatch includes the following steps:

[0050] (1) First, use a low-speed mixer to stir metallocene PP, antioxidant, lubricant, and PE wax according to the mass parts shown in Table 1. The stirring speed is 50 revolutions per minute, and the stirring time is 5 minutes. After stirring, a mixture is obtained for feeding into the bottom of the internal mixer.

[0051] (2) According to the process sequence of first feeding talcum powder and then feeding PP, first open the feeding pipeline inlet valve of talcum powder to feed modified talcum powder, and then open the feeding pipeline inlet valve of PP to feed the mixture obtained in step (1). Set the temperature at the bottom of the internal mixer to 170 °C, start the main engine of the internal mixer, the speed is 40 revolutions per minute, start the pressure cover to press down the material for kneading. During the kneading process of the material, pay attention to observing the material temperature display on the control panel, and control the stop time of the internal mixing by the rise of the material temperature to a certain value. In addition, the pressure cover is lifted for exhaust and repeated pressing 6 times during the whole internal mixing process, with an interval of 1.5 minutes each time. The material is compacted, plasticized, and kneaded into a rubber block premix under the action of the pressure cover. Stop kneading and discharging when the material temperature display rises to 175 °C to obtain a rubber block premix.

[0052] (3) Pour the rubber block premix obtained in step (2) into the hopper of the elevator, start the elevator to send the rubber block premix into the hopper of the conical twin-screw feeder. The premix is fed into the single-screw extruder through the conical twin-screw feeder, extruded through the die at a certain speed by the single-screw extruder, cut into pellets by a hot cutter and air-cooled, and then transported and sieved by a multi-stage blower to send the product into the finished product warehouse, thus obtaining the PP-based talcum powder masterbatch.

[0053] The process settings of the single-screw extruder are as follows: Zone 1 of the feeding section is 150 °C, Zone 2 is 165 °C, Zone 3 is 165 °C, Zone 4 is 165 °C, Zone 5 is 165 °C, Zone 6 of the die head is 170 °C, and the speed of the extruder is 40 revolutions per minute.

[0054] Comparative Examples 1-5

[0055] The differences between Comparative Examples 1-5 and the Examples lie only in the types and ratios of components, as shown in Table 1.

[0056] Among the components of each Example and Comparative Example,

[0057] The metallocene PP is LG Chem MH1700, with a melting point (tested by DSC method) of 150 °C and a melt index of 40 g / 10 min (GB / T3682.1-2018, 230 °C / 2.16 kg);

[0058] The common PP is homopolymer PP, Shanghai Secco S2040, with a melting point (tested by DSC method) of 165 °C and a melt index of 40 g / 10 min (GB / T3682.1-2018, 230 °C / 2.16 kg);

[0059] The modified talc powder 1 is obtained by mixing and reacting talc powder A, silane coupling agent, low-viscosity hydroxyl silicone oil, and medium-high-viscosity hydroxyl silicone oil; the addition amount of the silane coupling agent is 0.7% of the mass of talc powder A; the addition amount of the low-viscosity hydroxyl silicone oil is 0.5% of the mass of talc powder A; the addition amount of the medium-high-viscosity hydroxyl silicone oil is 0.5% of the mass of talc powder A; the grade of talc powder A is AH-1250N6, the particle size D90 is 10 μm, the whiteness is 92, the silica content is 60%, the calcium oxide content is 3%, produced by Guangxi Huamei Talc Development Co., Ltd.; the silane coupling agent is amino silane coupling agent KH550, sourced from the market; the low-viscosity hydroxyl silicone oil is Dow Corning PMX-0156, with a viscosity of 100 mPa·s; the medium-high-viscosity hydroxyl silicone oil is Shandong Jueneng Chemical Co., Ltd. JN203-2000, with a viscosity of 2000 mPa·s;

[0060] The preparation method of the modified talc powder 1 specifically includes the following steps: Pour the silane coupling agent into a container and preheat it in an 80 °C constant temperature oven for 2 hours. Use the same method to preheat the low-viscosity hydroxyl silicone oil in an 80 °C constant temperature oven for 2 hours. Additionally, use the same method to preheat the medium-high-viscosity hydroxyl silicone oil in a 120 °C constant temperature oven for 2 hours; then put talc powder A into a high-speed mixer according to the production ratio, and pour the preheated silane coupling agent, low-viscosity hydroxyl silicone oil, and medium-high-viscosity hydroxyl silicone oil into it according to the ratio. Start the high-speed mixer, set the mixing temperature to 120 °C, the rotation speed to 900 revolutions per minute, and the mixing time to 8 minutes. The talc powder undergoes a chemical reaction with the above modifiers at high speed. After mixing, the modified talc powder 1 is obtained;

[0061] The modified talcum powder 2 is obtained by mixing and reacting talcum powder A, silane coupling agent, and low-viscosity hydroxy silicone oil; the addition amount of the silane coupling agent is 0.7% of the mass of talcum powder A; the addition amount of the low-viscosity hydroxy silicone oil is 0.5% of the mass of talcum powder A. The specific preparation method refers to that of modified talcum powder 1. That is, the difference between the modified talcum powder 2 and the modified talcum powder 1 is only that it is only graft-modified by the silane coupling agent and the low-viscosity hydroxy silicone oil, without modification by medium- and high-viscosity hydroxy silicone oil;

[0062] The modified talcum powder 3 is obtained by mixing and reacting talcum powder A, silane coupling agent, and medium- and high-viscosity hydroxy silicone oil; the addition amount of the silane coupling agent is 0.7% of the mass of talcum powder A; the addition amount of the medium- and high-viscosity hydroxy silicone oil is 0.5% of the mass of talcum powder A. The specific preparation method refers to that of modified talcum powder 1. That is, the difference between the modified talcum powder 3 and the modified talcum powder 1 is only that it is only graft-modified by the silane coupling agent and the medium- and high-viscosity hydroxy silicone oil, without modification by low-viscosity hydroxy silicone oil;

[0063] The modified talcum powder 4 is obtained by mixing and reacting talcum powder A and silane coupling agent; the addition amount of the silane coupling agent is 0.7% of the mass of talcum powder A. The specific preparation method refers to that of modified talcum powder 1. That is, the difference between the modified talcum powder 4 and the modified talcum powder 1 is only that it is only graft-modified by the silane coupling agent, without modification by low-viscosity hydroxy silicone oil and medium- and high-viscosity hydroxy silicone oil;

[0064] The modified talcum powder 5 is obtained by mixing and reacting talcum powder A, low-viscosity hydroxy silicone oil, and medium- and high-viscosity hydroxy silicone oil; the addition amount of the low-viscosity hydroxy silicone oil is 0.5% of the mass of talcum powder A; the addition amount of the medium- and high-viscosity hydroxy silicone oil is 0.5% of the mass of talcum powder A. The specific preparation method refers to that of modified talcum powder 1. That is, the difference between the modified talcum powder 5 and the modified talcum powder 1 is only that it is only graft-modified by low-viscosity and medium- and high-viscosity hydroxy silicone oil, without modification by silane coupling agent;

[0065] The talcum powder B is of model SL92-10, with a particle size D90 of 10 μm, a whiteness of 92, a silicon dioxide content of 57%, and a calcium oxide content of 5%. It is produced by Guangxi Huamei Talcum Powder Development Co., Ltd. That is, the difference between the talcum powder B and the talcum powder A is only that its silicon dioxide content is lower than that of talcum powder A, and its calcium oxide content is higher than that of talcum powder A;

[0066] The antioxidant A is a mixture of antioxidant TH-412S (thioester auxiliary antioxidant), antioxidant 1010 (hindered phenol antioxidant), and antioxidant 168 (phosphite ester), and the compounding ratio is 50%:20%:30% in sequence;

[0067] The antioxidant B is a mixture of antioxidant 1010 (hindered phenol antioxidant) and antioxidant 168 (phosphite), and the compounding ratio is 50%:50% in sequence;

[0068] The lubricant is calcium stearate, commercially available;

[0069] The PE wax has a number average molecular weight of 2000 and is commercially available;

[0070] Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are the same kind.

[0071] Table 1 Content of each component in the materials of the examples and comparative examples (parts)

[0072]

[0073] The PP-based talc masterbatch prepared in the examples and comparative examples and the talc masterbatch of control products 1 and 2 are added to PP (Yanshan Petrochemical K7726) resin at a ratio of 25%, mixed evenly, and the talc-modified PP composite is prepared by a twin-screw extruder; the control product 1 is: talc masterbatch 1, PP carrier, talc content 80%, talc particle size D90 equal to 10 μm, silicon dioxide content 60%, origin Guangxi; the control product 2 is: talc masterbatch 2, PP carrier, talc content 80%; talc particle size D90 equal to 9 μm, silicon dioxide content 61%, origin Suzhou.

[0074] Then, the talc A (grade AH-1250N6) selected in the examples is added to PP (Yanshan Petrochemical K7726) by the powder addition method at a ratio of 20%, and the talc-modified PP composite is prepared by the same processing technology, as the powder method-modified PP composite.

[0075] The prepared talc-modified PP composites and pure PP resin (Yanshan Petrochemical K7726) are used to injection mold color plates, bending test specimens and impact test specimens by an injection molding machine. After the test specimens are placed in a constant temperature room at 23°C for 24 hours for conditioning, they are tested to characterize the application effect of each talc masterbatch in modified PP. The color Lab values of the color plates of each sample are detected by a color difference meter, where the color L value is used to characterize whiteness, and the higher the L value, the higher the whiteness; the color b value is used to characterize the yellow phase, and the higher the b value, the yellower it is, and the lower the b value, the bluer it is. The bending performance is detected by a universal tensile machine according to GB / T9341-2008, and the bending modulus index can characterize the rigidity of the material. The cantilever beam notched impact strength at room temperature (23°C) of each sample is detected by a pendulum impact testing machine according to GB / T1843-2008.

[0076] The test results are shown in Table 2.

[0077] Table 2 Performance test results of the composite materials of the examples, comparative examples and reference samples

[0078]

[0079] As can be seen from Table 2, the talc masterbatch prepared in Examples 1-3 has a high L value and a low b value when applied in PP, indicating better white quality and a very small yellowing trend of the background color. It is basically equivalent to the color quality of the modified PP composite material prepared by the method of adding talc powder, indicating that the white quality of the talc masterbatch of the present invention has almost no decrease compared with the original talc; Examples 4-5 are modified talc by compounding a single-viscosity hydroxy silicone oil and a silane coupling agent, and the impact strength retention rate of the prepared PP composite material is lower than that of Examples 1-3; in Example 6, the antioxidant is a compound of antioxidant 1010 and antioxidant 168, and the yellowing trend during the manufacturing process is higher than that of the antioxidant systems in Examples 1-5.

[0080] In Comparative Example 1, ordinary PP is used as the carrier, and its melting point is higher than that of metallocene PP. From melting to the completion of internal mixing of the material, its processing temperature window is narrower than that of metallocene PP, and the mixing and dispersion effects of the material are inferior to those of metallocene PP. The talc masterbatch prepared is applied to the talc PP composite material, and the b value of the color is higher than that of the example, and the impact strength is lower than that of the example.

[0081] Comparative Example 2 uses the same talc as the example, but the talc is not surface-grafted and modified. The yellowing trend of the material during the manufacturing process is higher than that of the modified talc. In addition, the impact strength of the modified PP composite material without surface grafting modification is relatively low.

[0082] Comparative Example 3 uses ordinary talc, which has a low silicon dioxide content and a high calcium oxide content, and is not surface-grafted and modified. The yellowing trend of the material is higher than that of the example and Comparative Example 2, and the impact strength of the modified PP composite material without surface grafting modification is lower than that of the example and Comparative Example 2.

[0083] In Comparative Example 4, only a single silane coupling agent is used to modify talc. The talc masterbatch prepared is applied to the modified PP composite material, and the impact strength of the material is inferior to that of the talc masterbatch prepared by co-modifying talc with a silane coupling agent and a hydroxy silicone oil.

[0084] In Comparative Example 5, only hydroxy silicone oil is used to modify talc. The talc masterbatch prepared is applied to the modified PP composite material, and the impact strength of the material is also inferior to that of the talc masterbatch prepared by co-modifying talc with a silane coupling agent and a hydroxy silicone oil.

[0085] Reference samples 1 and 2 are two typical PP-based talc masterbatches on the market. Compared with the talc masterbatch prepared by the present invention, their color quality is average, and the impact strength retention rate when applied to the modified PP composite material is relatively low.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PP-based talcum powder masterbatch, characterized in that, By mass parts, it includes the following components: 15 - 25 parts of metallocene PP, 75 - 85 parts of talc powder co - modified by silane coupling agent and hydroxy silicone oil, 0.3 - 0.6 parts of antioxidant, 0.2 - 0.5 parts of lubricant, 0.2 - 0.5 parts of PE wax; the particle size D90 of the talc powder is 8μm - 15μm, the whiteness ≥ 90, the silicon dioxide content ≥ 59%, and the calcium oxide content ≤ 4%; the melting point of the metallocene PP is 150℃ - 160℃; the talc powder co - modified by silane coupling agent and hydroxy silicone oil is obtained by mixing and reacting talc powder, silane coupling agent and hydroxy silicone oil; the addition amount of the silane coupling agent is 0.5% - 1% of the mass of the talc powder; the addition amount of the hydroxy silicone oil is 0.3% - 1% of the mass of the talc powder.

2. The PP-based talcum powder masterbatch according to claim 1, wherein The melt index of the metallocene PP is 20g / 10min - 100g / 10min.

3. The PP-based talcum powder masterbatch according to claim 1, characterized in that, The silane coupling agent includes amino silane coupling agent; and / or, the hydroxy silicone oil includes bis - hydroxy - terminated siloxane.

4. The PP-based talcum powder masterbatch according to claim 1, characterized in that, The hydroxy silicone oil includes at least one of low - viscosity hydroxy silicone oil and medium - high - viscosity hydroxy silicone oil. The viscosity of the low - viscosity hydroxy silicone oil is 25 - 100mPa·s; the viscosity of the medium - high - viscosity hydroxy silicone oil is 750 - 3000mPa·s.

5. The PP-based talcum powder masterbatch according to claim 1, characterized in that, The hydroxy silicone oil includes low - viscosity hydroxy silicone oil and medium - high - viscosity hydroxy silicone oil, and the mass ratio of the low - viscosity hydroxy silicone oil to the medium - high - viscosity hydroxy silicone oil is (0.3 - 0.5):(0.3 - 0.5).

6. The PP-based talcum powder masterbatch according to claim 1, wherein The antioxidant includes at least one of thioester antioxidants, hindered phenol antioxidants, and phosphite antioxidants; and / or, the lubricant includes stearate; and / or, the molecular weight of the PE wax is 1000 - 3000.

7. The PP-based talcum powder masterbatch according to claim 1, wherein The antioxidant, by mass percentage, includes 40% - 60% of thioester antioxidants, 10% - 30% of hindered phenol antioxidants, and 20% - 40% of phosphite antioxidants.

8. A method for preparing the PP-based talcum powder masterbatch according to any one of claims 1-7, characterized in that, It includes the following steps: (1) Mix metallocene PP, antioxidant, lubricant, and PE wax evenly according to the said mass parts to obtain a mixture. (2) First add the talc powder co - modified by silane coupling agent and hydroxy silicone oil into a kneader, and then add the mixture obtained in step (1), and knead to obtain a pre - mixed rubber block. (3) Extrude and pelletize the pre - mixed rubber block obtained in step (2) through a single - screw extruder to obtain the PP - based talc masterbatch.

9. The application of the PP - based talc masterbatch according to any one of claims 1 - 7 in the preparation of household appliances, automobiles, and electronic and electrical appliances.

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